How to change the bobbin

Abstract

The present invention relates to a bobbin replacement method for automatically connecting an electrode sheet to a new bobbin via a control unit. Specifically, the bobbin replacement method of the present invention includes a first winding step of winding an electrode sheet onto a first bobbin, a step of preparing a second bobbin having double-sided tape and a marking sticker attached to one side thereof and positioned a predetermined distance away from the electrode sheet, a position adjusting step of rotating the second bobbin to adjust a stop position of the second bobbin, an attaching step of moving the second bobbin so that the double-sided tape is attached to the electrode sheet, a cutting step of cutting the electrode sheet extending between the first bobbin and the second bobbin around which the electrode sheet is wound, and a second winding step of rotating the second bobbin to wind the electrode sheet onto the second bobbin, wherein in the position adjusting step, the control unit controls the stop position of the second bobbin based on the position of the marking sticker.

Description

[Technical Field]

[0001] The present invention relates to a bobbin replacement method, and more specifically to a bobbin replacement method that can efficiently automate the replacement of bobbins that wind electrode sheets.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0132331, dated October 5, 2023, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] An unwinder and a rewinder are used when transporting an electrode sheet in a roll-to-roll state for manufacturing a secondary battery. The electrode sheet roll is chucked and coupled to the unwinder and the rewinder, and the electrode sheet is transported in a roll-to-roll state between the unwinder and the rewinder and undergoes predetermined processing.

[0004] The electrode sheet roll chucked by the unwinder and rewinder has a structure in which the electrodes are wound around a bobbin. If the electrode sheet is wound directly onto the bobbin, the wound electrode portion will be lost, even though it is usable. Therefore, instead of directly connecting the electrode sheet to the bobbin, a vinyl base film or the like is first wound around the bobbin, and then the electrode sheet is connected onto the wound base film.

[0005] In this case, transparent double-sided tape can be used to attach the electrode sheet to the base film, but because double-sided tape is transparent and cannot be recognized by visual sensors, a problem occurs in that the process is delayed until the position of the double-sided tape is confirmed using a conventional visual sensor.

[0006] Due to the above problems, the position of the double-sided tape is checked by the worker himself, but this method is very troublesome and reduces the process efficiency. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Korean Patent Publication No. 10-2020-0136198 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, the present invention has been devised to solve the above-mentioned problems, and an object of the present invention is to provide a method that can automatically attach an electrode sheet to a new bobbin during the process of winding the electrode sheet.

[0009] Another object of the present invention is to provide a method for efficiently attaching an electrode sheet to a new bobbin during the process of connecting the electrode sheet to a new bobbin.

[0010] Other objects and advantages of the present invention can be understood from the following description and more clearly understood from the embodiments of the present invention. Also, it will be easily understood that the objects and advantages of the present invention can be realized by the means and combinations thereof as claimed in the claims. [Means for solving the problem]

[0011] According to the present invention, there is provided a bobbin replacement method for automatically connecting an electrode sheet to a new bobbin via a control unit. The bobbin replacement method includes: a first winding step of winding an electrode sheet onto a first bobbin; a step of preparing a second bobbin having double-sided tape and a marking sticker attached to one side thereof and positioned a predetermined distance away from the electrode sheet; a position adjusting step of rotating the second bobbin to adjust a stop position of the second bobbin; an attaching step of moving the second bobbin so that the double-sided tape is attached to the electrode sheet; a cutting step of cutting the electrode sheet extending between the first bobbin on which the electrode sheet is wound and the second bobbin; and a second winding step of rotating the second bobbin to wind the electrode sheet onto the second bobbin, wherein in the position adjusting step, the control unit controls the stop position of the second bobbin based on the position of the marking sticker.

[0012] A base film may be provided on the edge of the second bobbin, and the double-sided tape may be placed on the base film.

[0013] The substrate film can include polyethylene terephthalate.

[0014] The second bobbin may include a marking sticker on one side, and the marking sticker may be attached at a position corresponding to the double-sided tape.

[0015] The marking sticker can be positioned on the side of the double-sided tape with respect to the longitudinal direction of the second bobbin.

[0016] The marking sticker may be located at least at one of the upper and lower portions of the double-sided tape in the width direction of the second bobbin.

[0017] The marking sticker can be positioned so that it overlaps the double-sided tape.

[0018] The marking sticker may be in the form of either a dot or a line.

[0019] The control unit can recognize the marking sticker corresponding to the position of the double-sided tape via the color sensor.

[0020] The double-sided tape is configured to be colorless and substantially transparent in the visible light range, the marking sticker is configured to be colored, and the color sensor can recognize the color of the marking sticker.

[0021] The control unit recognizes the position of the double-sided tape based on the position of the marking sticker, and in the position adjusting step, the control unit can rotate the second bobbin so that the double-sided tape faces one side of the electrode sheet.

[0022] The control unit can control the rotation of the second bobbin to stop when the double-sided tape is positioned opposite the electrode sheet, and move the stopped second bobbin toward the electrode sheet so that the double-sided tape is attached to the electrode sheet.

[0023] The control unit can control the cutting unit having a blade at an end to cut the electrode sheet adjacent to the second bobbin in the width direction.

[0024] The second bobbin may be configured to be rotatable about a rotation axis and to move toward and away from the electrode sheet. [Effects of the Invention]

[0025] According to the present invention, the process of connecting an electrode sheet to a new bobbin during winding can be automated, thereby improving process efficiency and reducing the amount of electrode sheet wasted during the process of connecting the electrode sheet to the bobbin. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a perspective view of an electrode sheet being wound around a bobbin and a winding unit according to a first embodiment of the present invention. FIG. [Figure 2]3 is a flowchart illustrating a bobbin replacement method according to the present invention. [Figure 3] FIG. 10 is a schematic diagram showing a simplified process flow from the position adjusting step to the cutting step. [Figure 4] FIG. 10 is a perspective view of the second bobbin rotating in the position adjustment step. [Figure 5] FIG. 1 is a perspective view of a cutting unit of the present invention. [Figure 6] 6 is a perspective view of a winding unit illustrating a process of cutting an electrode sheet with the cutting unit of FIG. 5. FIG. [Figure 7] FIG. 10 is a perspective view of a second bobbin according to a second embodiment of the present invention. [Figure 8] FIG. 10 is a perspective view of a second bobbin according to a third embodiment of the present invention. [Figure 9] FIG. 10 is a perspective view of a second bobbin according to a fourth embodiment of the present invention. [Figure 10] FIG. 10 is a perspective view of a second bobbin according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. As a premise, the terms and words used in this specification and claims are not to be construed as being limited to their general or dictionary meanings, but are to be construed as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the terms in order to best describe his / her own invention.

[0028] Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and therefore there may be various equivalents and modifications that can replace them at the time of this application.

[0029] Furthermore, in the description of the present invention, if it is determined that a specific description of related publicly known configurations or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0030] The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and therefore the shapes and sizes of components in the drawings may be exaggerated, omitted, or illustrated schematically for clearer explanation. Therefore, the sizes and proportions of each component do not completely reflect the actual sizes and proportions.

[0031] The present invention relates to a bobbin replacement method, and more specifically to a bobbin replacement method that can efficiently automate the replacement of bobbins that wind electrode sheets.

[0032] 1 to 6 relate to a winding unit and a bobbin replacement method according to a first embodiment of the present invention, and FIGS. 7 to 10 relate to winding units according to second to fifth embodiments of the present invention, respectively.

[0033] The empty bobbin and the bobbin replacement method using the same of the present invention will be described in detail below with reference to the accompanying drawings. For reference, the directions of front, back, up, down, left, and right used in the following description to specify relative positions are intended to aid in understanding the invention, and unless otherwise specified, the directions shown in the drawings shall be used as the basis.

[0034] Here, the longitudinal direction of the electrode sheet corresponds to the direction in which the electrode sheet moves, and the width direction of the electrode sheet corresponds to the direction perpendicular to the longitudinal direction of the electrode sheet.

[0035] Furthermore, the width direction of the bobbin refers to the longitudinal direction of the electrode sheet, and the longitudinal direction of the bobbin refers to the width direction of the electrode sheet.

[0036] (First embodiment) <Rewinding unit 1> FIG. 1 is a perspective view of an electrode sheet S being wound around a bobbin and a winding unit 1 according to a first embodiment of the present invention.

[0037] The winding unit 1 includes a bobbin for winding the electrode sheet S, a color sensor 60 for detecting the position of the bobbin, and a cutting unit 70 for cutting the electrode sheet S in the width direction of the electrode sheet S.

[0038] The bobbins include a first bobbin 10 that takes up the electrode sheet S in advance as shown in FIG. 1, and a second bobbin 20 that stands by to take over from the first bobbin 10 and continue to take up the electrode sheet S when the amount of electrode sheet S taken up on the first bobbin 10 exceeds a certain amount.

[0039] The bobbin includes double sided tape 40 and a marking sticker 50 on one side.

[0040] The double-sided tape 40 is used to attach the electrode sheet S, and one side is attached to the edge of the bobbin, while the other side remains exposed to the outside before being attached to the electrode sheet S.

[0041] The double-sided tape 40 is made of a vinyl film with adhesive or pressure-sensitive adhesive applied to both sides.

[0042] The double-sided tape 40 is colorless. More specifically, the double-sided tape 40 is colorless and substantially transparent in the visible light range.

[0043] The marking sticker 50 is included in a position corresponding to the double-sided tape 40 and is made of a color.

[0044] The winding unit 1 of the present invention may further include a base film 30 that wraps around the edge of the bobbin. The base film 30 is used to protect the electrode sheet S or to replace a portion of the electrode sheet S that may be discarded due to damage during processing.

[0045] Specifically, the base film 30 is attached to the surface of the bobbin so as to be in close contact with the surface, and the double-sided tape 40 and the marking sticker 50 are attached to the base film 30 attached to the bobbin.

[0046] The substrate film 30 is made of a plastic material, and may include, for example, a polyethylene terephthalate material.

[0047] The bobbins are configured to be not only rotatable around the rotation axis A but also movable in the horizontal and vertical directions. Therefore, it is possible to adjust the position of the first bobbin 10 that winds up the electrode sheet S, and also to adjust the position of the second bobbin 20 that is on standby.

[0048] The color sensor 60 is a sensor that can recognize a specific color, and preferably recognizes the color of the marking sticker 50 included in the bobbin.

[0049] The color sensor 60 is disposed adjacent to the second bobbin 20 at a position that does not interfere with the transfer of the electrode sheet S or the movement of the bobbin. At this time, the color sensor 60 is disposed so as to face the direction of the second bobbin 20 as shown in FIG.

[0050] The cutting unit 70 is used to cut and separate the electrode sheet S wound around the first bobbin 10 from the electrode sheet S attached to the second bobbin 20 .

[0051] More specific details regarding the cutting unit 70 will be explained later in the cutting step of the bobbin replacement method.

[0052] The operation of the winding unit 1 of the present invention is controlled via a control unit, which can control the rotation and movement of the bobbin.

[0053] The control unit receives information in advance regarding the first bobbin 10 to be wound, the path of the electrode sheet S to be wound, the second bobbin 20 waiting on the electrode sheet S, and the attachment positions of the double-sided tape 40 and marking sticker 50 on the second bobbin 20, and controls the operation of the bobbins based on this information, replacing the first bobbin 10 with the second bobbin 20.

[0054] The control unit receives the position information of the marking sticker 50 recognized by the color sensor 60. The control unit can then estimate the position of the double-sided tape 40 based on the position of the marking sticker 50.

[0055] Specifically, the control unit estimates the position of the double-sided tape 40 inversely via the position information of the marking sticker 50 sent from the color sensor 60 based on the position information of the marking sticker 50 and the double-sided tape 40 that has been input in advance.

[0056] As a result, the control unit controls the rotation of the second bobbin 20 so that the finally calculated double-sided tape 40 is positioned opposite the surface of the electrode sheet S wound around the first bobbin 10.

[0057] <How to change the bobbin> The bobbin replacement method of the present invention is characterized in that all steps are automatically performed under the control of a control unit so that the replacement operation can be performed accurately when connecting the electrode sheet S to a new bobbin.

[0058] FIG. 2 is a flowchart showing the bobbin replacement method of the present invention, and FIG. 3 is a schematic diagram showing a simplified process flow from the position adjusting step to the cutting step.

[0059] Referring to FIG. 2, the bobbin replacement method of the present invention can be divided into a bobbin preparation step, an empty bobbin preparation step, a position adjustment step, an attachment step, a cutting step, and a winding step.

[0060] <(S1) First winding step> This is a step in which the electrode sheet S is wound onto the first bobbin 10.

[0061] The electrode sheet S is transported in one direction toward the first bobbin 10.

[0062] The first bobbin 10 rotates in one direction around a rotation axis A, and the electrode sheet S connected to the first bobbin 10 is wound up under tension due to the rotation of the first bobbin 10.

[0063] The first bobbin 10 is rotated by a separately connected motor, and the transport speed and winding speed of the electrode sheet can be adjusted according to the output of the motor.

[0064] <(S2) Second bobbin 20 preparation step> This is a step of preparing a second bobbin 20 having a double-sided tape 40 and a marking sticker 50 attached to one side thereof and disposed at a predetermined distance from the electrode sheet S.

[0065] The second bobbin 20 includes a double-sided tape 40 and a marking sticker 50 on one side, as shown in FIG.

[0066] The second bobbin 20 is rotatable about a rotation axis A and configured to be movable to the electrode sheet S wound on the first bobbin 10. That is, the second bobbin 20 is configured to be able to move forward and backward facing the electrode sheet S. At this time, the second bobbin 20 is provided so that the rotation axis A is horizontal to the rotation axis A of the first bobbin 10.

[0067] Since the second bobbin 20 must operate independently of the first bobbin 10, the second bobbin 20 is rotated by a motor separate from the motor connected to the first bobbin 10.

[0068] In some embodiments, the edge of the second bobbin 20 may be provided with a base film 30 , and the double-sided tape 40 and the marking sticker 50 may be placed on the base film 30 .

[0069] The base film 30 is made of a plastic material, for example, polyethylene terephthalate.

[0070] As shown in FIG. 1, the second bobbin 20 included in the winding unit 1 according to the first embodiment of the present invention has a marking sticker 50 positioned next to the side of the double-sided tape 40, with the longitudinal direction of the second bobbin 20 as the reference.

[0071] In some embodiments, the marking sticker 50 may be in the form of a dot, as shown in FIG.

[0072] Also, in this step or the previous step, a color sensor 60 capable of recognizing the marking sticker 50 on the second bobbin 20 may be arranged and prepared.

[0073] The color sensor 60 is fixedly disposed in the space between the first bobbin 10 and the second bobbin 20 so as to face the direction of the second bobbin 20. More specifically, the color sensor 60 is disposed so that the double-sided tape 40 on the second bobbin 20 can be positioned exactly opposite the electrode sheet S when the color sensor 60 recognizes the marking sticker 50. Therefore, the double-sided tape 40 attached to the second bobbin 20 faces the electrode sheet S when the color sensor 60 recognizes the marking sticker 50.

[0074] <(S3) Position adjustment step> This is a step of rotating the second bobbin 20 and adjusting the stop position of the second bobbin 20.

[0075] The control unit of the present invention causes the second bobbin 20 to spin freely so that the color sensor 60 can recognize the marking sticker 50 on the second bobbin 20, as shown in FIG.

[0076] FIG. 4 is a perspective view of the second bobbin 20 rotating in the position adjustment step.

[0077] Based on the previously input positional relationship between the marking sticker 50 and the double-sided tape 40 and the positional information of the electrode sheet S, the control unit rotates the second bobbin 20 so that the double-sided tape 40 faces the surface of the electrode sheet S. Thereafter, as shown in FIGS. 2 and 4, the control unit stops the rotation of the second bobbin 20 when the color sensor 60 recognizes the marking sticker 50. In other words, when the second bobbin 20 stops, the double-sided tape 40 on the second bobbin 20 faces the upper surface of the electrode sheet S.

[0078] <(S4) Adhesion step> This is a step of moving the second bobbin 20 so that the double-sided tape 40 is attached to the electrode sheet S.

[0079] As shown in FIG. 3, the control unit moves the second bobbin 20 linearly toward the electrode sheet S while maintaining the state in which the double-sided tape 40 faces the electrode sheet S.

[0080] Therefore, the double-sided tape 40 on the second bobbin 20 is attached to the electrode sheet S in a state where it is interposed between the second bobbin 20 and the surface of the electrode sheet S.

[0081] One side of the electrode sheet S attached to the double-sided tape 40 is fixed to the second bobbin 20 by the double-sided tape 40 .

[0082] <(S5) Cutting Step> This is a step of cutting the electrode sheet S that extends between the first bobbin 10 and the second bobbin 20 on which the electrode sheet S is wound.

[0083] The cutting is performed by a cutting unit 70 which includes a blade 71 at its end.

[0084] More specifically, the control unit controls the cutting unit 70 having a blade 71 at its end to cut the electrode sheet S adjacent to the second bobbin 20 in the width direction.

[0085] The cutting unit 70 may be in the form of a plate that stands vertically with respect to the surface of the electrode sheet S.

[0086] FIG. 5 is a perspective view of a cutting unit 70 that can be used in some embodiments, and FIG. 6 is a perspective view of the winding unit 1 illustrating the process of cutting the electrode sheet S with the cutting unit 70 of FIG.

[0087] The cutting unit 70 has a blade 71 formed at its lower end as shown in FIG. 5, and moves vertically up and down, so that it can cut the electrode sheet S passing underneath as shown in FIGS.

[0088] The cutting proceeds along the width direction of the electrode sheet S, and the electrode sheet S connected to the first bobbin 10 is completely separated from the electrode sheet S connected to the second bobbin 20 by the cutting.

[0089] However, the cutting unit 70 is not limited to the shape shown in Figures 5 and 6, and any shape that can cut the electrode sheet S in the width direction of the electrode sheet S can be used. For example, the cutting unit 70 can be a rotating circular blade 71.

[0090] <(S6) Second winding step> This is a step in which the second bobbin 20 is rotated and the electrode sheet S is wound onto the second bobbin 20.

[0091] According to FIG. 3, the first bobbin 10 on which a certain amount of electrode sheet S has been wound is separated and moved to another process, and the remaining electrode sheet S is wound onto the second bobbin 20 again as the second bobbin 20 rotates.

[0092] (Second to fifth embodiments) <Rewinding unit 1> The marking sticker 50 included in the winding unit 1 of the present invention can be provided in various positions, not just the side of the second bobbin 20. That is, as long as the control unit of the present invention recognizes the positional relationship between the double-sided tape 40 and the marking sticker 50, the position of the marking sticker 50 can be adjusted in various ways.

[0093] That is, the marking sticker 50 may be located at least one of the upper and lower parts of the double-sided tape 40 based on the width direction of the second bobbin 20, or may be located so as to overlap the double-sided tape 40.

[0094] Moreover, the marking sticker 50 may be provided in a linear shape, unlike the marking sticker 50 included in the winding unit 1 according to the first embodiment.

[0095] FIG. 7 is a perspective view of a second bobbin 20 according to a second embodiment of the present invention.

[0096] The marking sticker 50 provided on the second bobbin 20 is located below the double-sided tape 40 with respect to the width direction of the second bobbin 20 .

[0097] In this case, the color sensor 60 is disposed on the same horizontal line on the front or rear surface of the second bobbin 20, and can recognize the marking sticker 50. In other words, the degree of freedom in arranging the color sensor 60 can be further increased.

[0098] FIG. 8 is a perspective view of a second bobbin 20 according to a third embodiment of the present invention.

[0099] According to FIG. 8, the marking sticker 50 is positioned so as to overlap the double-sided tape 40 .

[0100] In this case, there is no need to perform two processes of attaching the double-sided tape 40 and the marking sticker 50 to the second bobbin 20 or the base film 30, respectively, and the double-sided tape 40 with the marking sticker 50 attached thereto is attached at once.

[0101] That is, the double-sided tape 40 with the marking sticker 50 attached thereto has the effect of simplifying the process and improving efficiency.

[0102] FIG. 9 is a perspective view of a second bobbin 20 according to a fourth embodiment of the present invention.

[0103] 9, the marking sticker 50 is provided linearly on the side of the double-sided tape 40. Specifically, the marking sticker 50 extends in the rotational direction of the second bobbin 20, i.e., along the circumferential direction of the second bobbin 20.

[0104] The marking sticker 50 has the effect of increasing the accuracy of recognition by the color sensor 60 by providing a wider area that the color sensor 60 can recognize.

[0105] FIG. 10 is a perspective view of a second bobbin 20 according to a fifth embodiment of the present invention.

[0106] According to FIG. 10, the marking sticker 50 extends along the width direction of the second bobbin 20 below the double-sided tape 40 .

[0107] In this case, there is an advantage that the effects of the marking sticker 50 according to the second embodiment and the fourth embodiment can be obtained at the same time.

[0108] The present invention has been described in more detail above with reference to the drawings, embodiments, etc. However, the configurations described in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore, at the time of filing this application, there may be various equivalents and modifications that can replace them. [Explanation of symbols]

[0109] 1: Winding unit 10: First bobbin 20: Second bobbin 30: Base film 40: Double-sided tape 50: Marking sticker 60: Color sensor 70: Cutting unit 71: Blade S: Electrode sheet A: Rotation axis

Claims

1. A bobbin replacement method for automatically connecting an electrode sheet to a new bobbin via a control unit, a first winding step of winding the electrode sheet onto a first bobbin; preparing a second bobbin having a double-sided tape and a marking sticker attached to one side thereof and spaced a predetermined distance from the electrode sheet; a position adjusting step of rotating the second bobbin and adjusting a stop position of the second bobbin; a attaching step of moving the second bobbin so that the double-sided tape is attached to the electrode sheet; a cutting step of cutting the electrode sheet extending between the first bobbin around which the electrode sheet is wound and the second bobbin; a second winding step of rotating the second bobbin and winding the electrode sheet onto the second bobbin, In the position adjusting step, the control unit controls the stop position of the second bobbin based on the position of the marking sticker.

2. a base film is provided on an edge of the second bobbin; The bobbin replacement method according to claim 1 , wherein the double-sided tape is disposed on the base film.

3. The bobbin replacement method according to claim 2 , wherein the base film comprises polyethylene terephthalate.

4. the second bobbin includes a marking sticker on one side; The bobbin replacement method according to claim 1 , wherein the marking sticker is attached to a position corresponding to the double-sided tape.

5. The bobbin replacement method according to claim 4 , wherein the marking sticker is located on a side of the double-sided tape with respect to the longitudinal direction of the second bobbin.

6. The bobbin replacement method according to claim 4 , wherein the marking sticker is located at least one of an upper part and a lower part of the double-sided tape in a width direction of the second bobbin.

7. The bobbin replacement method according to claim 4 , wherein the marking sticker is positioned so as to overlap the double-sided tape.

8. The bobbin replacement method according to claim 4, wherein the marking sticker is in the form of one of a dot and a line.

9. The bobbin replacement method according to claim 4 , wherein the control unit recognizes a marking sticker corresponding to the position of the double-sided tape via a color sensor.

10. The double-sided tape is colorless and transparent in the visible light range, The marking sticker is made of color, The bobbin replacement method according to claim 9 , wherein the color sensor recognizes the color of the marking sticker.

11. the control unit recognizes the position of the double-sided tape based on the position of the marking sticker, The bobbin replacement method according to claim 9 , wherein in the position adjusting step, the control unit rotates the second bobbin so that the double-sided tape faces the surface of the electrode sheet.

12. 12. The bobbin replacement method of claim 11, wherein the control unit stops the rotation of the second bobbin when the double-sided tape faces the electrode sheet, and controls the stopped second bobbin to move toward the electrode sheet so that the double-sided tape is attached to the electrode sheet.

13. The bobbin replacement method according to claim 1 , wherein the control unit controls a cutting unit having a blade at an end to cut the electrode sheet adjacent to the second bobbin in the width direction.

14. The bobbin replacement method according to claim 1 , wherein the second bobbin is rotatable about a rotation axis and configured to move toward and away from the electrode sheet.

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