JP6209900B2 - Sheet electrode manufacturing method and rolling device control method - Google Patents

Description

The present invention relates to a method for producing a sheet-like electrode and a method for controlling a rolling device used for producing the sheet-like electrode .

  When rolling an active material on the surface of a sheet-like electrode using a rolling roller, the surface of the sheet-like electrode may be damaged by the active material adhering to the surface of the rolling roller. We are cleaning. For example, there is known a cleaning device that scrapes off toner adhering to the surface of an image carrier using a rubber blade (see, for example, Patent Document 1).

JP-A-4-249285

  When rolling an active material on the surface of a sheet-like electrode using a rolling roller, if the surface of the sheet-like electrode is damaged by the active material adhering to the surface of the rolling roller, the rolling accuracy may be lowered. In this case, if the surface of the rolling roller is cleaned using a blade such as the above technique, even if the blade is made of rubber, the function of the blade must be hardened. There is a problem that precise film thickness control of the member may be difficult.

The problem to be solved by the present invention is to provide a sheet-like electrode manufacturing method and a rolling device control method capable of improving the rolling accuracy.

  The present invention removes the active material from the defective coating portion of the electrode member by the pair of removing rollers provided upstream of the pair of rolling rollers, and the rolling roller passes when the defective coating portion passes the rolling roller. The above-mentioned problem is solved by moving them in directions away from each other.

  According to the present invention, the active material is removed from the defective coating portion of the electrode member by the removing roller, and the rolling roller moves in a direction away from each other at the defective coating portion, so that the active material adheres to the rolling roller. This can suppress rolling and improve rolling accuracy.

FIG. 1 is an overall conceptual diagram showing a rolling device in an embodiment of the present invention. 2 (A) and 2 (B) are diagrams showing electrode members in the present embodiment, FIG. 2 (A) is a perspective view, and FIG. 2 (B) is IIB-IIB in FIG. 2 (A). It is sectional drawing along a line. 3 (A) and 3 (B) are enlarged views of a portion III in FIG. 1, and FIG. 3 (A) is a view showing a state before the removal roller removes a defective coating portion of the active material. (B) is a figure which shows after the removal roller removed the coating defect part of the active material. FIG. 4 is a flowchart at the time of rolling of the rolling device in the embodiment of the present invention. 5 (A) to FIG. 5 (C) are enlarged views of a portion V in FIG. 1, and FIG. 5 (A) is a diagram illustrating a portion before the active material coating failure passes through the rolling roller. 5 (B) is a view when a poorly coated area of the active material passes through the rolling roller, and FIG. 5 (C) is a view after the poorly coated area of the active material passes through the rolling roller.

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

  FIG. 1 is an overall conceptual diagram showing a rolling device 1 in the present embodiment, and FIGS. 2A and 2B are diagrams showing an electrode member 10 in the present embodiment. FIG. 4B is an enlarged view of a portion III in FIG. 1 before and after the removal roller 41 removes a coating failure portion 121 (described later) of the active material layer 12, and FIG. 4 is a flowchart at the time of rolling of the rolling device 1 in the present embodiment. 5 (A) to 5 (C) are enlarged views of a portion V in FIG. 1 when a coating failure portion 101 (described later) of the active material layer 12 passes through the rolling rollers 61 and 62.

  As shown in FIG. 1, the rolling device 1 according to the present embodiment includes a feed roller 2, a preheating unit 3, a removal unit 4, a detection unit 5, a rolling unit 6, a winding roller 7, and a control unit 8. And.

  The electrode member 10 is a member used as an electrode of a lithium ion secondary battery or the like, and includes a current collector 11 and an active material layer 12 as shown in FIG. The current collector 11 has a long strip shape, and is formed from an aluminum foil, a copper foil, or the like.

  The active material layer 12 is composed of a paste obtained by dispersing a powder of an electrode active material (positive electrode active material or negative electrode active material) with a conductive agent, a thickener, and a binder using a dispersion medium. Examples of the positive electrode active material include lithium cobaltate, lithium nickelate, and lithium manganate. Moreover, as a negative electrode active material, graphite, carbon, a lithium aluminum alloy, a tin oxide, etc. can be illustrated.

  The active material layer 12 is formed by applying the paste on both surfaces of the current collector 11 and then drying the paste. As shown in FIGS. 2 (A) and 2 (B), the active material layer 12 is collected. It is formed at predetermined intervals in the longitudinal direction of the electric body 11. The thickness D of the active material layer 12 is 70 μm to 200 μm, but the thickness of the active material layer 12 is not particularly limited.

  As shown in FIG. 1, the feed roller 2 is provided upstream of the preheating unit 3. The paste in which the electrode active material is dispersed is applied to both sides of the current collector 11 on the feed roller 2. The electrode member 10 in a dry state is wound in a roll shape. The electrode member 10 is continuously supplied to the preheating unit 3, the removing unit 4, the detecting unit 5, and the rolling unit 6 by rotating the feed roller 2 counterclockwise in the drawing. In the present embodiment, “upstream side” and “downstream side” are based on the transport direction of the electrode member 10 during rolling.

  The preheating unit 3 heats the electrode member 10 before rolling so as to reach a temperature near the melting point temperature (for example, 80 ° C. to 130 ° C.) of the active material layer 12, and the removal rollers 41 and 42 are poorly coated by the heating. The first preheating roller 31 and the second preheating roller 32 are provided as shown in FIG. A heat transfer heater and a temperature sensor (not shown) are arranged inside the first and second preheating rollers 31 and 32, and the surface temperature of the first and second preheating rollers 31 and 32 is kept constant. It is possible to keep. The electrode member 10 is conveyed while the first and second preheating rollers 31 and 32 are rotated, and the electrode member 10 is heated while the peripheral surfaces of the preheating rollers 31 and 32 are in contact with the electrode member 10. The

  The removal portion 4 is a portion where the active material layer 12 is easily peeled off from the current collector 11 because the coating of the active material layer 12 is not sufficient in the electrode member 10 (hereinafter also referred to as a poor coating portion 101). ) From the active material layer 12, which has a function of removing in advance a portion 121 (hereinafter also referred to as a coating failure portion 121) that is poorly coated. The removal unit 4 is provided between the preheating unit 3 and the detection unit 5, and includes a first removal roller 41 and a second removal roller 42. In addition, the 1st and 2nd removal rollers 41 and 42 in this embodiment are equivalent to an example of a pair of removal roller of this invention.

  As shown in FIGS. 1 and 3A, the first removal roller 41 is provided so as to be in contact with the upper surface of the electrode member 10 while rotating clockwise in the drawing along the conveying speed of the electrode member 10. It has been. On the other hand, the second removal roller 42 is provided so as to come into contact with the lower surface of the electrode member 10 while rotating counterclockwise in the drawing along the conveying speed of the electrode member 10. The first and second removal rollers 41 and 42 are arranged to face each other with the electrode member 10 interposed therebetween.

  Although not particularly shown, the first and second removal rollers 41 and 42 have an axial center position adjusting mechanism, and the distance between the rotating shaft centers of the rollers can be adjusted by the mechanism. Yes. Then, by adjusting the distance between the axial centers of the first and second removal rollers 41 and 42, a predetermined pressing force is applied to the electrode member 10 passing between the removal rollers 41 and 42 from above and below. It is possible to add.

  Due to this pressing force, the defective coating portion 121 (see FIG. 3A) generated on the upper side in FIG. 1 of the electrode member 10 adheres to the peripheral surface of the first removal roller 41 and is removed from the electrode member 10. (See FIG. 3B). Similarly, when the defective coating portion 121 occurs on the lower side of the electrode member 10 in FIG. 1, the defective coating portion 121 adheres to the peripheral surface of the second removal roller 42 in a similar manner from the electrode member 10. Removed. The pressing force by the first and second removal rollers 41 and 42 is preferably 4% to 8% of the pressing force when the rolling rollers 61 and 63 press the electrode member 10, and is preferably 4% to 4%. More preferably, it is 5%. In this case, the accuracy of removing the defective coating portion 121 from the electrode member 10 is improved.

  Inside the first and second removal rollers 41 and 42, a heat transfer heater and a temperature sensor (not shown) are arranged, and the surface temperature of the first and second removal rollers 41 and 42 is kept constant. It is possible to keep. Thereby, the temperature of the said removal rollers 41 and 42 is maintained at the same temperature (for example, 80 to 130 degreeC) as the 1st and 2nd preheating rollers 31 and 32. Note that the temperature of the first and second removal rollers 41 and 42 may be set to be about 20 ° C. higher than the temperature of the preheating rollers 31 and 32.

  The diameters of the first and second removal rollers 41 and 42 are preferably 150 mm to 200 mm. In this case, when the electrode member 10 passes between the first and second removal rollers 41 and 42, it is possible to ensure a long contact time between the removal rollers 41 and 42 and the electrode member 10, It becomes easy to keep the temperature of the surface of the removal rollers 41 and 42 uniform. As a result, the efficiency of heating the electrode member 10 is improved and the coating failure portion 121 is likely to adhere to the peripheral surfaces of the removal rollers 41 and 42, so that the accuracy of removing the coating failure portion 121 is further improved. .

  Further, the surface roughness (Rmax) of the first and second removal rollers 41 and 42 is preferably 0.1 s to 0.5 s. In this case, the coating failure portion 121 is more likely to adhere to the peripheral surfaces of the removal rollers 41 and 42, and the accuracy of removing the coating failure portion 121 is further improved.

  On the right side of the first removal roller 41 in FIG. 1, a blade 411 having substantially the same width as the first removal roller 41 and arranged along the axial direction of the removal roller 41 is provided. Yes. When the first removal roller 41 rotates in a state where the tip of the blade 411 is in contact with the peripheral surface of the first removal roller 41, the defective coating portion 121 attached to the peripheral surface of the first removal roller 41. It is possible to scrape off. Then, the poorly coated portion 121 that has been scraped off is collected by the collection unit 412. The positions where the blade 411 and the collection unit 412 are provided are not particularly limited.

  On the left side of the second removal roller 42 in FIG. 1, similarly, a blade 421 having substantially the same width as the second removal roller 42 and arranged along the axial direction of the removal roller 42. Is provided. The coating failure adhered to the peripheral surface of the second removal roller 42 by rotating the second removal roller 42 with the tip of the blade 421 in contact with the peripheral surface of the second removal roller 42. The part 121 can be scraped off. The poor coating portion 121 that has been scraped off is collected by the collection unit 422. Note that the positions where the blade 421 and the collection unit 422 are provided are not particularly limited.

  Further, a camera 413 is provided above the first removal roller 41 in FIG. 1, and the camera 413 captures an image of the defective coating portion 121 attached to the peripheral surface of the first removal roller 41. Similarly, a camera 423 is also provided below the second removal roller 42 in FIG. 1, and the camera 423 captures an image of the defective coating portion 121 attached to the peripheral surface of the second removal roller 42. These cameras 413 and 423 are cameras provided with imaging elements such as CCD elements and CMOS elements, for example, and imaging data from the cameras 413 and 423 are sent to the control unit 8. Then, the control unit 8 performs image processing on the imaged data, and detects the defective coating portion 121. Instead of the cameras 413 and 423, the defective coating portion 121 may be detected by an optical sensor or the like. Further, the positions where the cameras 413 and 423 are provided are not particularly limited.

  The detection unit 5 has a function of detecting a poor coating portion 101 of the electrode member 10. As shown in FIG. 1, the detection unit 5 is provided between the removal unit 4 and the rolling unit 6. For example, the detection unit 5 includes a first camera 51 and a second camera provided with an image sensor such as a CCD element or a CMOS element. The camera 52 is provided.

  The first camera 51 is disposed on the upper side in FIG. 1, images the upper surface of the electrode member 10, and sends the image data to the control unit 8. The control unit 8 detects the defective coating portion 101 based on the imaging data. Specifically, the trace of the coating failure portion 121 removed by the first removal roller 41 (coating failure portion 101) has the color of the current collector 11 (aluminum, copper, etc.). On the other hand, the color of the other coating part (part in which the active material layer 12 is normally formed) is black or light black. Image processing using RGB values and HSV values is performed on the image data captured by the first camera 51, and the defective coating portion 101 is detected by recognizing the difference in color tone.

  The second camera 52 is disposed on the lower side in FIG. 1, images the lower surface of the electrode member 10 in the same manner as the first camera 51, and sends the image data to the control unit 8. Then, the controller 8 detects the coating failure portion 101.

  The rolling unit 6 has a function of rolling the electrode member 10, and includes a first rolling roller 61 and a second rolling roller 62 disposed so as to face each other via the electrode member 10, A drive mechanism 63 and a second drive mechanism 64 are provided. The first drive mechanism 63 includes a drive unit 631 and a support unit 632, and the second drive mechanism 64 includes a drive unit 641 and a support unit 642.

  Inside the first and second rolling rollers 61 and 62, a heat transfer heater and a temperature sensor (not shown) are arranged, and the surface temperature of the first and second rolling rollers 61 and 62 is kept constant. It is possible to keep. Thereby, the temperature of the said rolling rollers 61 and 62 is maintained at the same temperature as the 1st and 2nd preheating rollers 31 and 32 (for example, 80 to 130 degreeC). Note that the temperature of the first and second rolling rollers 61 and 62 may be set to be about 20 ° C. higher than the temperature of the preheating rollers 31 and 32.

  The first rolling roller 61 is provided on the upper side in FIG. 1, and its axis is supported by the support portion 632 of the first drive mechanism 63. The first drive mechanism 63 can move the support unit 632 up and down by a motor or the like (not shown) built in the drive unit 631 in response to a command from the control unit 8. By the vertical movement of the support portion 632, the first rolling roller 61 can move in a direction approaching or separating from the second rolling roller 62.

  The second rolling roller 62 is provided on the lower side in FIG. 1, and its axis is supported by the support portion 642 of the second drive mechanism 64. The second drive mechanism 64 can also move the support unit 642 up and down by a motor or the like (not shown) built in the drive unit 641 in response to a command from the control unit 8. In addition, the second rolling roller 62 can also move in a direction approaching or separating from the first rolling roller 61 by the vertical movement of the support portion 642.

  The first and second drive mechanisms 63 and 64 press and roll the electrode member 10 passing between the first and second rolling rollers 61 and 62 with a predetermined pressure. The pressing force at this time is appropriately adjusted depending on the thickness of the electrode member 10 or the type and thickness of the active material layer 12. For example, the pressing force may be set so that the thickness of the electrode member 10 after rolling is 60% to 70% with respect to the thickness of the electrode member 10 before rolling. Not. In addition, the 1st and 2nd rolling rollers 61 and 62 in this embodiment are equivalent to an example of a pair of rolling roller of this invention.

  The winding roller 7 is provided on the downstream side of the rolling unit 6 and winds up the rolled electrode member 10 in a roll shape. By rotating the winding roller 7 counterclockwise in FIG. 1, the rolled electrode member 10 is continuously collected. In this embodiment, the rolled electrode member 10 is cooled by natural cooling, but the rolled electrode member 10 is cooled by providing a cooler or the like between the rolling unit 6 and the winding roller 7. May be.

  The detection unit 5 and the rolling unit 6 described above are controlled by the control unit 8. The control unit 8 has a function of executing a program stored in a ROM or the like by a CPU, and is composed of, for example, a computer. Hereinafter, the control performed by the control unit 8 will be described with reference to FIG.

  The active material layer 12 of the electrode member 10 delivered from the delivery roller 2 is heated to a predetermined temperature when passing through the preheating part 3 (S101), and then the defective coating part 121 is removed by the removal part 4 ( S102).

  At this time, if it is not confirmed from the imaging data by the cameras 413, 423 that the poor coating portion 121 is attached to the peripheral surface of the first or second removal roller 41, 42 (in the case of No in S103), The control unit 8 performs control so that the first and second rolling rollers 61 and 62 are in a state of being close to each other (rolling state) (S104). Then, the rolled electrode member 10 is wound around the winding roller 7.

  On the other hand, when it is confirmed from the image data obtained by the cameras 413 and 423 that the defective coating portion 121 is attached to the peripheral surface of the first or second removing roller 41 or 42 (Yes in S103), the blade The defective coating portion 21 is scraped off by 411 or the blade 421 (S105).

  Next, when the control unit 8 detects the location where the defective coating portion 121 in the electrode member 10 has been peeled off (the poor coating portion 101), based on the data captured by the first or second camera 51 or 52 of the detection unit 5. (S106), control is performed so that the first and second rolling rollers 61 and 62 move in directions away from each other (S107).

  In this case, for example, as shown in FIGS. 5 (A) to 5 (C), the control unit 8 has a poor coating portion 101 only on one surface of the electrode member 10 (only the upper surface in the example in the figure) Only the rolling roller on one side (first rolling roller 61 in FIG. 5B) is moved away from the rolling roller on the other side (second rolling roller 62 in FIG. 5B). You may control, and you may control to move both the 1st and 2nd rolling rollers 61 and 62 so that it may mutually space apart. In the present embodiment, as shown in the example shown in FIG. 5B, when the coating failure portion 101 passes through the rolling rollers 61 and 62, the rolling roller 61 (the rolling roller 61 in the example of FIG. 5B). ) And the electrode member 10 are controlled so as to move out of contact with each other, but the rolling rollers 61 and 62 may be in contact with the electrode member 10.

  Next, when the control unit 8 confirms that the defective coating portion 101 does not exist based on the imaging data by the first or second camera 51 or 52 of the detection unit 5 (Yes in S108), the first and second The rolling rollers 61 and 62 are controlled so as to be close to each other (rolling state) (S104).

  On the other hand, while it is confirmed by the imaging data by the first or second camera 51, 52 of the detection unit 5 that the coating failure portion 101 exists (No in S108), the first and second The control unit 8 controls so that the rolling rollers 61 and 62 remain separated from each other (S107). Thereafter, when it is confirmed from the image data obtained by the cameras 51 and 52 that the defective coating portion 101 no longer exists due to the conveyance of the electrode member 10 (when it becomes Yes in S108), the control unit 8 performs the first and first operations. The two rolling rollers 61 and 62 are controlled so as to be close to each other (rolling state) (S104).

  After the rolling of the electrode member 10 by the rolling apparatus 1 is finished, the electrode member 10 is formed and heated in a heating furnace (not shown), thereby alleviating uneven distortion existing in the electrode member 10. Subsequently, the said electrode member 10 is cut | judged so that it may become a desired shape, and a sheet-like electrode member is completed.

  Next, the operation of this embodiment will be described.

  In the present embodiment, the removal portion 4 removes in advance the poor coating portion 121 from a location where the active material layer 12 is insufficiently formed in the electrode member 10 (the poor coating portion 101). Further, when the poor coating portion 101 passes, the pair of rolling rollers 61 and 62 are moved in directions away from each other. Thereby, at the time of rolling by the rolling rollers 61 and 62, the defective coating portion 121 adheres to the peripheral surface of the rolling rollers 61 and 62, and the newly conveyed electrode member 10 is damaged by the deposits. Can be suppressed. For this reason, the precision of rolling by the rolling device 1 can be improved.

  Further, since it is not necessary to clean the rolling rollers 61 and 62 in order to remove the adhesion of the defective coating portion 121, it is possible to improve the rolling yield and to improve the circumference of the rolling rollers 61 and 62 that may occur during the cleaning. Surface damage can also be suppressed.

  In the present embodiment, the preheating unit 3 that preheats the active material layer 12 of the electrode member 10 is provided on the upstream side of the first and second removal rollers 41 and 42. Thereby, when the defective coating part 121 is removed by the removal rollers 41 and 42, the defective coating part 121 is easily removed from the electrode member 10, and the rolling accuracy by the rolling device 1 can be further improved.

  Moreover, the diameter of the 1st and 2nd removal rollers 41 and 42 in this embodiment is 150 mm-200 mm. For this reason, when the electrode member 10 passes between the first and second removal rollers 41 and 42, it is possible to ensure a long contact time between the removal rollers 41 and 42 and the electrode member 10, and to remove the electrode member 10. It becomes easy to keep the temperature of the surfaces of the rollers 41 and 42 uniform. As a result, the efficiency of heating the electrode member 10 is improved, and the defective coating portion 121 is likely to adhere to the peripheral surfaces of the removal rollers 41 and 42, so that the accuracy of removing the defective coating portion 121 is further improved. .

  Moreover, in this embodiment, when the poor coating part 101 of the electrode member 10 passes through the rolling part 6, the rolling rollers 61 and 62 and the electrode member 10 are not in contact with each other. Move. Thereby, the damage of the peripheral surface of the said rolling rollers 61 and 62 by the edge 102 (refer FIG.5 (A)-FIG.5 (C)) of the said coating poor part 101 contacting the rolling rollers 61 and 62 is suppressed. Thus, the rolling accuracy by the rolling device 1 can be further improved.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Rolling apparatus 10 ... Electrode member 101 ... Coated defective part 11 ... Current collector 12 ... Active material layer 121 ... Coated defective part 3 ... Preheating part 4. ..Removal part 41 ... first removal roller 42 ... second removal roller 5 ... detection part 6 ... rolling part 61 ... first rolling roller 62 ... second Rolling roller 8 ... Control unit

Claims (4)

  An electrode member having a current collector and an active material coated on the current collector is a method for producing a sheet-like electrode that is rolled while being heated by a pair of rolling rollers,
  By the pair of removal rollers, the active material is removed from the defective coating portion of the electrode member,
  After removing the active material, detect the poor coating site,
  A method for manufacturing a sheet-like electrode, wherein after detecting the coating failure site, the rolling roller moves in a direction away from each other when the coating failure site passes through the rolling roller.   It is a manufacturing method of the sheet-like electrode according to claim 1,
  A method for producing a sheet-like electrode in which the electrode member is preheated before removing the active material.   It is a manufacturing method of the sheet-like electrode according to claim 1 or 2,
  A manufacturing method of a sheet-like electrode in which the rolling roller is moved to a position where the rolling roller and the electrode member are not in contact with each other when the poor coating portion passes through the rolling roller.   A pair of rolling rollers for rolling while heating an electrode member having a current collector and an active material coated on the current collector;
  A pair of removal rollers provided upstream of the rolling roller;
  A detection unit;
  A control unit that controls the rolling roller based on information from the detection unit,
  By the removal roller, the active material is removed from the coating failure site in the electrode member,
  After removing the active material, the detection unit detects the coating failure site,
  A control method for a rolling apparatus, wherein after detecting the coating failure site, the control unit moves the rolling roller in a direction away from each other when the coating failure site passes through the rolling roller.

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