Electrode foil unwinding device

Abstract

To provide an electrode foil unwinding device facilitating joining and cutting of new and old electrode foils and carrying-in / out of a roll accompanying replacement of an electrode foil roll when the remaining amount of a sheet-like electrode foil becomes small.SOLUTION: The electrode foil unwinding device 3 comprises a support part 4 for holding a roll 2 of the electrode foil 1 horizontally rotatably and detachably, and a guide part 5 for changing the traveling direction of the electrode foil by winding the electrode foil over the support part, wherein a foil cutting table 20 having a plate shape having a length equal to or more than the width of the electrode foil and temporarily fixing the electrode foil to the front face by bringing the foil into contact with the front face, and a rotating mechanism 23 for rotating the foil cutting table between a retreat position between the roll held by the support part and the electrode foil whose traveling direction is changed by the guide part, and a predetermined working position on the rear side opposite to the front side in the traveling direction of the electrode foil passed through the guide part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an apparatus for continuously unwinding rolled electrode foil onto which electrode material is applied when manufacturing an electrode sheet by applying the electrode material that constitutes a secondary battery, and in particular to an electrode foil unwinding apparatus equipped with a mechanism for connecting the electrode foil on an old roll with the electrode foil on a new roll when replacing the roll. [Background technology]

[0002] When continuously unwinding (releasing) a rolled film- or sheet-like material (hereinafter referred to as sheet material) to continuously produce, for example, electrode sheets for secondary batteries, the amount of sheet material that can be wound on a roll is limited, so the roll must be replaced. Patent Document 1 describes an apparatus configured to replace the roll from which the sheet material is to be unwound when continuously producing electrode sheets.

[0003] To briefly explain the configuration of this device, a pair of roll body holding units, cutting means, and attachment means are provided. The roll body holding units are configured to hold a roll around which the separator is wound horizontally and rotatably, and the pair of roll body holding units are arranged close to each other with their rotation axes horizontal. A guide roller is provided above the middle of these roll body holding units to wrap the separator unwound upward from the roll and change its running direction to horizontal.

[0004] The attachment means is a means for attaching the leading end of the separator unwound from the roll and holding it at a predetermined high position, and is located below the guide roller. The pair of attachment means are located opposite each other on either side of the separator stretched between the roll and the guide roller, sandwiching the separator being unwound and a newly unwound separator to join them. Cutting means are located below each attachment means and are configured to cut any separator stretched between the roll and the guide roller that is running low. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-15115 Summary of the Invention [Problem to be solved by the invention]

[0006] The device described in Patent Document 1 automates the joining and cutting of old and new separators when the roll that supplies the separator is replaced. Therefore, the device described in Patent Document 1 needs to have a new roll on standby during the so-called running period, when the separator is continuously unwound to produce an electrode sheet. To achieve this, the device described in Patent Document 1 is provided with two sets of roll body holders, cutting means, and attachment means, one for the old roll and one for the new roll. Additionally, two sets of actuators and control units that operate the attachment means and cutting means are provided.

[0007] Conventional devices that automate the joining and cutting of sheet materials have had problems such as an increase in the number of components, making the device larger overall, and requiring a large amount of space. In particular, the device described in Patent Document 1 is configured so that two rolls are arranged parallel to each other, meaning that the rolls are loaded and unloaded in opposite directions. This requires space for roll replacement, and can complicate roll handling.

[0008] The present invention has been made against the background of the above circumstances, and aims to provide an electrode foil unwinding device that facilitates joining and cutting of old and new electrode foil and easy transport of the roll when the remaining amount of sheet-like electrode foil is low and the electrode foil roll needs to be replaced. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the present invention provides an electrode foil unwinding device comprising: a support section that holds a roll of electrode foil in a horizontally rotatable and detachable manner; and a guide section that wraps the electrode foil above the support section to change the running direction of the electrode foil; a foil cutting table that is plate-shaped and has a length equal to or greater than the width of the electrode foil and that contacts the electrode foil with its front surface to temporarily secure the electrode foil to the front surface; and a rotation mechanism that rotates the foil cutting table to a retracted position between the roll held by the support section and the electrode foil whose running direction has been changed by the guide section, and to a predetermined working position that is lower than the retracted position and is on the rear side of the roll held by the support section, opposite to the front side in the running direction of the electrode foil that has passed through the guide section.

[0010] In the present invention, the rotation mechanism may include arm members provided on both sides of the roll held by the support portion and having both end portions of the foil cutting table attached thereto, and a receiving portion that rotatably supports the arm members so that the foil cutting table rotates between the retracted position and the working position on the outer periphery of the roll.

[0011] In the present invention, the foil cutting table may be provided on the front surface with either a magnet for clamping the electrode foil or a magnetic body to which the magnet is attracted.

[0012] In the present invention, the foil cutting table may have a groove formed in the center in the width direction along the longitudinal direction. [Effects of the Invention]

[0013] According to the present invention, when the foil cutting table is rotated from the retracted position to the working position by the rotation mechanism, the foil cutting table pushes the electrode foil stretched between the roll and the guide unit from its back side (rear side) into the working position. In this case, the electrode foil is wrapped around the foil cutting table. The electrode foil is temporarily attached to the foil cutting table by being in close contact with the front of the foil cutting table, so that the electrode foil can be cut on the foil cutting table to separate the temporarily attached portion from the portion remaining wound on the roll. By rotating the foil cutting table to the retracted position in this state, the working position side of the roll is released, so the roll can be removed from the support unit and a new roll can be fed into and held by the support unit. In other words, the old roll can be replaced with a new one.

[0014] A predetermined length of electrode foil is unwound from the new roll, and the foil cutter table is then rotated to the working position. The so-called rear end of the electrode foil unwound from the old roll is held by the foil cutter table and lowered to the working position. The leading end of the electrode foil unwound from the new roll is then placed on the foil cutter table over the rear end of the electrode foil from the old roll, aligning and joining the two ends. After that, the electrode foil is released from its temporary attachment to the foil cutter table, and the foil cutter table is rotated to the waiting position, completing the roll change.

[0015] Since this work is performed behind the guide section in the direction in which the electrode foil travels, sufficient work space is ensured, making the work easy, and the roll can be removed (carried out) from the support section and carried in from the same direction, making the work easy. Furthermore, since there is no need to ensure space for cutting, joining, etc. of the electrode foil along the path along which the electrode foil unwound from the roll travels, the length of the line in which the electrode foil is processed can be shortened, and even if defective portions of the electrode foil due to cutting and joining are discarded when the roll is replaced, the discarded length can be kept as short as possible, thereby improving material yield. [Brief explanation of the drawings]

[0016] [Figure 1]1 is a schematic diagram for explaining a processing line including an unwinding device according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the unwinding device, with some parts omitted, taken along a plane perpendicular to the central axis of the roll, showing the state in which the electrode foil is being unwound. [Figure 3] FIG. 1 is a front view schematically illustrating an example of a stand. [Figure 4] FIG. 2 is a partially omitted front view of an example of a foil cutting table. [Figure 5] FIG. 2 is a front view schematically illustrating an example of a rotation mechanism. [Figure 6] 3 is a cross-sectional view similar to FIG. 2, showing the foil cutting table lowered to the working position. [Figure 7] 3 is a cross-sectional view similar to FIG. 2, showing the electrode foil temporarily fixed to the front surface of the foil cutting table. [Figure 8] 3 is a cross-sectional view similar to FIG. 2, illustrating a state in which the electrode foil is wound around a roll with only a small amount remaining. [Figure 9] 3 is a cross-sectional view similar to FIG. 2, illustrating a state in which the foil cutting table temporarily fastening the rear end portion of the electrode foil remaining on the line has been rotated to a standby position. [Figure 10] 3 is a cross-sectional view similar to FIG. 2, illustrating the state in which the ends of the electrode foil of the new roll and the electrode foil of the old roll are temporarily fastened on a foil cutting table lowered to the working position. FIG. [Figure 11] 3 is a cross-sectional view similar to FIG. 2, illustrating a state in which the foil cutting table has been returned to the retreated position and the electrode foil is being allowed to run. DETAILED DESCRIPTION OF THE INVENTION

[0017] Next, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the embodiment described below is merely an example of how the present invention can be implemented, and is not intended to limit the present invention.

[0018] The unwinding device in an embodiment of the present invention is a device that continuously unwinds (pays out) electrode foil, which is coated with an electrode active material and used as an electrode for a secondary battery, from a roll. Figure 1 shows a schematic diagram of the process. Electrode foil 1 is a metal sheet or film, such as aluminum, several tens of micrometers thick and 1 meter or more wide, and is wound into a roll 2. Unwinding device 3 includes a roll stand (support unit) 4 that supports roll 2, and a guide roller (guide unit) 5 that wraps around electrode foil 1 unwound upward from roll 2 and changes its running direction (feed direction).

[0019] A first processing unit 6 is disposed adjacent to the front side (right side in FIG. 1 ) in the running direction of the unwound electrode foil 1. This first processing unit 6 is a unit that performs, for example, pre-coating treatment on the electrode foil 1, such as a process of applying predetermined marks at regular intervals to the electrode foil 1. Next to this is a second processing unit 7. This second processing unit 7 is a unit that, for example, applies an electrode active material at a predetermined pitch to the continuously running electrode foil 1. Between this second processing unit 7 and the first processing unit 6, a workspace is provided for an operator 8 who manages the coating process.

[0020] The mechanism for supporting the roll 2 in the unwinding device 3 will now be described. The roll stand 4 is configured to rotatably support the roll 2 and to detachably support the roll 2. An example of the roll stand 4 is shown schematically in Figures 2 and 3. The roll 2 is formed by winding multiple layers of electrode foil 1 around a roll core 9 that is hollow at least at both ends in the axial direction, and the roll stand 4 has a pair of left and right support parts 10 that hold the roll core 9.

[0021] Each support section 10 has a movable table 12 that moves back and forth on a machine base section 11 in the axial direction of the roll 2. A support shaft 13 that is inserted into the end of the roll core 9 is provided on the movable table 12. More specifically, the machine base sections 11 located on both sides in the axial direction of the roll 2 are provided with linear guides 14 that face the axial direction of the roll 2, and a slider 15 rests on the linear guide 14. Above the slider 15, another linear guide 16 is provided that faces the axial direction of the roll 2, and the movable table 12 rests on the other linear guide 16.

[0022] The actuator 17 that moves the movable table 12 back and forth is a hydraulically or pneumatically operated cylinder, and although not shown in Figure 3, it is arranged on the machine base 11 to the side of the movable table 12, facing the direction of back and forth movement of the movable table 12. The movable part (e.g., a rod) of the actuator 17 is connected to the movable table 12. Therefore, the roll stand 4 is configured so that by moving the support shafts 13 together with the movable table 12 backward in a direction that widens the gap between them, the support shafts 13 come out of the roll core 9, the roll 2 is removed from the unwinding device 3, and a new roll 2 is fed between the support shafts 13 and held there.

[0023] The direction of removal (discharge) and feed (intake) of the roll 2 is a horizontal direction perpendicular to the central axis of the support shaft 13, and more specifically, the roll 2 is discharged and carried in toward the rear side in the running direction of the electrode foil 1, or toward the opposite side from the first processing unit 6. In other words, in the direction in which the unwinding device 3, first processing unit 6, and second processing unit 7 are arranged, the roll 2 is carried in and out on the so-called open space side at the rear.

[0024] One of the left and right movable bases 12 is equipped with a motor 18 that rotates the support shaft 13. The motor 18 applies torque to the support shaft 13 to rotate the roll 2 supported by the support shaft 13, and is designed to prevent excessive tension from being applied to the electrode foil 1 being unwound. The motor 18 may be provided coaxially with the support shaft 13 to directly drive the support shaft 13, or it may be mounted on the movable base 12 in a direction perpendicular to the axis of the support shaft 13 by interposing a reduction mechanism between the motor and the support shaft 13.

[0025] A first guide roller 5 is disposed horizontally at a position higher than the roll 2 on the open space side where the roll 2 is loaded and unloaded. A second guide roller 5 is disposed horizontally on the opposite side of the first guide roller 5 from the open side (the forward side in the running direction of the electrode foil 1). A third guide roller 5 is disposed horizontally below the second guide roller 5. The electrode foil 1 is wrapped around the first and second guide rollers 5 from above. Therefore, the electrode foil 1 unwound from the upper side of the roll 2 is changed in direction and fed horizontally by the first and second guide rollers 5, then changes its feeding direction (running direction) downward from the second guide roller 5, wrapped around the third guide roller 5 from below, and fed horizontally again. These first to third guide rollers 5 are attached to a machine frame 19 that is integrated with the machine base 11 described above.

[0026] In order to replace a roll (old roll) 2 with a low amount of electrode foil 1 remaining with a new roll (new roll) 2 and continue the above-mentioned coating and other processes, a foil cutter 20 is provided that is used to cut the electrode foil 1 from the old roll 2 and connect the electrode foil 1 to the new roll 2. The foil cutter 20 is a member used to cut the electrode foil 1, temporarily fasten the cut ends, and join the old and new electrode foils 1, and in the embodiment described here, is a member in the shape of a long, narrow rectangular plate. An example is shown in Figure 4.

[0027] The foil cutter table 20 is longer than the width of the electrode foil 1 (axial length of the roll 2) and is wide enough to allow the so-called rear end of the electrode foil 1 already unwound toward the first processing unit 6 and the front end of the electrode foil 1 newly unwound from the roll 2 to be brought close to each other and temporarily secured. A longitudinal groove 21 is formed in the center of the front surface of the foil cutter table 20. This groove 21 allows the front end of a cutter (not shown) to fit into it and facilitates smooth cutter movement when the electrode foil 1, which is held in close contact with the front surface of the foil cutter table 20, is cut with the cutter. The electrode foil 1 may be temporarily secured by any suitable means, such as adhesive or clips. In the example described here, the electrode foil 1 is clamped and secured by magnets. That is, a magnetic material 22 or a magnet 22 is provided on the entire or part of the front surface of the foil cutter table 20.

[0028] The foil cutting table 20 is used when replacing the roll 2, and is otherwise configured to wait in a retracted position so as not to interfere with the unwinding of the electrode foil 1 or the loading and unloading of the roll 2. An example of a rotation mechanism 23 that moves the foil cutting table 20 between the retracted position and a working position where the electrode foil 1 is cut and joined (spliced) is shown schematically in Figures 5 and 2.

[0029] Similar to the movable base 12, the rotation mechanisms 23 are arranged on both sides of the roll 2 in the axial direction. Each of these rotation mechanisms 23 includes an arm member 24 to which both longitudinal ends of the foil cutter table 20 are fixed. In the example shown in FIG. 2, the arm member 24 is configured as a fan-shaped frame overall, and the foil cutter table 20 is attached to the end of the arc-shaped outer periphery with its front facing outward (the core of the fan-shaped portion faces away from it). The core of the fan-shaped arm member 24 is supported by a frame 26 so that it can rotate around an axis 25 parallel to the support shaft 13. The axis 25, which serves as the center of rotation, is located above and in front of the support shaft 13 (on the open space side). The distance from the axis 25 to the foil cutter table 20 is such that the foil cutter table 20 is located on the outer periphery of an unused roll 2 with the largest diameter. The axis 25 corresponds to the receiving portion in this embodiment of the present invention.

[0030] The foil cutter table 20 is in a retracted position approximately directly above the shaft 25, and the working position is reached by rotating the arm member 24 to rotate the foil cutter table 20 to approximately the same height as the shaft 25. In this working position, the foil cutter table 20 is attached to the arm member 24 so that its front faces away from the roll 2 (toward the open space). A pusher 27 is provided to apply the force of the arm member 24 to push the foil cutter table 20 up to the retracted position. In the example shown in FIG. 2 , this pusher 27 may be a gas cylinder configured to push a rod inserted into the cylinder with gas pressure. The pusher 27 is provided so as to connect a position on the frame 26 that is offset from the shaft 25 toward the open space and a position on the arm member 24 that is near the foil cutter table 20. The frame 26 may be provided with an appropriate stopper (not shown) to fix the arm member 24 when the foil cutter table 20 is in the retracted position and when it is in the working position.

[0031] Next, the cutting and connection of the electrode foil 1 that accompanies replacement of the roll 2 will be described. Figure 2 shows a state in which the amount of electrode foil 1 remaining on the roll 2 has decreased, and the electrode foil 1 unwound from the roll 2 is stretched between the roll 2 and the guide roller 5 above it. The foil cutter 20 is in a retracted position, and is located on the back side of the electrode foil 1 stretched between the roll 2 and the guide roller 5 above it (the surface that faces outward in the radial direction when wound around the roll 2).

[0032] To replace the roll 2, first, the rotation of the roll 2 and the running of the electrode foil 1 are stopped. Then, the foil cutting table 20 is rotated to the working position. For example, a stopper (not shown) provided on the frame 26 is removed and the arm member 24 is rotated to pull the foil cutting table 20 down to the working position. This operation is performed by an operator standing on the open space side and manually pulling the foil cutting table 20. Therefore, it is preferable to provide an appropriate handle on the foil cutting table 20 or the arm member 24.

[0033] Figure 6 shows the foil cutter table 20 pulled down to the working position. As mentioned above, the retracted position of the foil cutter table 20 is on the rear side of the electrode foil 1, whereas the working position is closer to the open space than the roll 2, so the foil cutter table 20 rotates to cross the electrode foil 1 stretched between the roll 2 and the guide roller 5. As a result, the electrode foil 1 is hooked onto the foil cutter table 20 and guided toward the working position as shown in Figure 6, where it is stretched from the roll 2 to the foil cutter table 20 at the working position and over the guide roller 5. In this case, the roll 2 is rotated to give slack to the electrode foil 1.

[0034] Next, the electrode foil 1 floating above the front of the foil cutting table 20 at the work position is brought into close contact with the front of the foil cutting table 20 and temporarily fixed. This state is shown schematically in Figure 7. As mentioned above, the front of the foil cutting table 20 is provided with a magnet 22 or a magnetic body 22, so if a magnet 22 is used, a magnetic plate, or if a magnetic body 22, a magnet, is brought close to the front of the foil cutting table 20 and attracted by magnetic force. The attracting positions (temporarily fixing positions) are preferably on both the top and bottom sides of the groove 21 in the foil cutting table 20.

[0035] In this state, the temporarily fixed electrode foil 1 is cut with an appropriate cutter (not shown). In this case, the cutting edge of the cutter is inserted into groove 21 and moved along groove 21. Therefore, the cutter is linearly guided by groove 21, and the cutting edge of the cutter is inside groove 21 and does not get caught, so electrode foil 1 can be easily cut linearly across its entire width.

[0036] The portion of the cut electrode foil 1 that faces the roll 2 is released from the temporary fastening. Specifically, the magnet or magnetic material below the groove 21 is removed. In this state, the support shaft 13 is rotated in the reverse direction by the motor 18, thereby winding the electrode foil 1 onto the roll 2. This state is shown schematically in FIG. 8.

[0037] Next, as shown in Figure 9, the foil cutter table 20 is rotated to the retracted position. This opens up the open space side of the unwinding device 3, allowing the roll 2 to be replaced. First, an appropriate cart (not shown) is inserted from the open space side under the roll 2 supported by the support shaft 13 to support the roll 2 from below. In this state, the left and right movable tables 12 are moved backward to remove the support shaft 13 from the roll core 9 of the roll 2. The roll 2 placed on the cart is then pulled out together with the cart toward the open space. Next, a new roll 2, which is prepared on another cart, is fed between the support shafts 13 from the open space side. In this state, the left and right movable tables 12 are moved forward to insert the respective support shafts 13 into the roll core 9, and the new roll 2 is held by the support shafts 13.

[0038] A predetermined length of electrode foil 1 is unwound from the new roll 2, and in this state, the foil cutter table 20 is lowered to the working position. This state is shown schematically in Figure 10. The so-called rear end of the electrode foil 1 unwound from the previous roll 2 is temporarily fastened to the foil cutter table 20, so the so-called leading end of the electrode foil 1 being unwound from the new roll 2 is brought into close contact with the front of the foil cutter table 20 and temporarily fastened by magnetic force so as to align with the rear end. That is, a magnet 22 or magnetic body 22 is placed on the electrode foil 1 and magnetically attracted to the front of the foil cutter table 20. In this case, it is difficult to accurately align the ends of the new and old electrode foils 1. Therefore, the ends can be easily aligned by overlapping them and cutting the overlapped ends in a straight line with an appropriate cutter.

[0039] Then, on the foil cutting table 20, an appropriate tape material 28 is applied to the ends of the old and new electrode foils 1 to connect them together. The electrode foil 1 is then temporarily released from the foil cutting table 20, and the foil cutting table 20 is rotated to its retracted position. For example, if a stopper provided on the frame 26 is removed, the arm member 24 is pushed by the pusher 27 and rotates, moving the foil cutting table 20 to its retracted position. This completes the connection between the old and new electrode foils 1, and the electrode foil 1 is then unwound from the new roll 2 by running the electrode foil 1. As shown in FIG. 11 , the electrode foil 1 is stretched between the new roll 2 and the first guide roller 5 above it.

[0040] The electrode foil 1 connected by tape material 28 is run without any processing, removed from the production line, and discarded because the connected portion does not become a product and there is a possibility that it will become a defective product due to being stopped for a long time from unwinding device 3 to second processing unit 7. The discarded length is the running length from unwinding device 3 to second processing unit 7 or a length with a predetermined margin added. In the above-described embodiment of the present invention, cutting and joining of electrode foil 1 is performed in an area that is originally wide, on the open space side of unwinding device 3, so there is no need to provide a space for this in the line from unwinding device 3 to second processing unit 7. As a result, the so-called line length can be shortened and the amount of electrode foil 1 discarded when roll 2 is replaced can be reduced, improving material yield.

[0041] Furthermore, since the roll 2 can be both carried in and out from the open space of the unwinding device 3, it is possible to reduce the installation space required for the unwinding device 3 and the entire production line including it, thereby reducing the manufacturing costs of electrodes for secondary batteries or secondary batteries.

[0042] The present invention is not limited to the above-described embodiment, and therefore the shapes and positions of the various components do not have to be those shown in the drawings, and may be modified as appropriate as long as the intended functions of the present invention are achieved. Furthermore, while the drawings show a configuration in which the surface facing outward in the radial direction when wound around a roll serves as the back surface of the electrode foil, the unwinding direction may be reversed, and the surface facing inward in the radial direction when wound around a roll may serve as the back surface of the electrode foil. [Explanation of symbols]

[0043] 1 Electrode foil 2 rolls 3 Unwinding device 4 roll stands 5 Guide roller 6 1st processing section 7 2nd processing section 8. Workers 9 Roll core 10 Support part 11 Machine base section 12 Movable platform 13 Support shaft 14 Linear guide 15 Slider 16 Linear guide 17 Actuators 18 Motor 19 Machine frame 20 Foil cutting table 21 Groove 22 Magnetic materials (magnets) 23 Rotation mechanism 24 Arm member 25 axes 26 frames 27 Pusher 28 Tape material

Claims

1. An electrode foil unwinding device comprising: a support part that holds a roll of electrode foil in a horizontally rotatable and detachable manner; and a guide part that wraps the electrode foil above the support part to change the running direction of the electrode foil, a foil cutting table having a plate shape with a length equal to or greater than the width of the electrode foil, the foil cutting table contacting the front surface of the electrode foil to temporarily fix the electrode foil to the front surface; a rotation mechanism that rotates the foil cutting table to a retracted position between the roll held by the support section and the electrode foil whose running direction has been changed by the guide section, and to a predetermined working position that is lower than the retracted position and is on the rear side, opposite to the front side, of the roll held by the support section in the running direction of the electrode foil that has passed through the guide section; An electrode foil unwinding device comprising:

2. The electrode foil unwinding device according to claim 1, The rotation mechanism includes: Arm members are provided on both sides of the roll held by the support portion and have both end portions of the foil cutting table attached thereto; a receiving portion that rotatably supports the arm member so that the foil cutting table can rotate between the retreat position and the working position on the outer circumferential side of the roll; An electrode foil unwinding device comprising:

3. The electrode foil unwinding device according to claim 1 or 2, The foil cutting table has, on the front surface thereof, either a magnet for clamping the electrode foil or a magnetic body to which the magnet is attracted. An electrode foil unwinding device characterized by the above.

4. The electrode foil unwinding device according to claim 1 or 2, The foil cutting table has a groove formed in the center in the width direction along the longitudinal direction. An electrode foil unwinding device characterized by the above.

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