Winding device

Abstract

Provided is a winding device capable of more surely preventing an unintended change in the circumferential length of a winding core due to a winding fastening force, and miniaturizing the winding core. This winding core includes: a fixed core piece 81; a movable core piece 82; a screw shaft 83 having a first screw part 83a and a second screw part 83b opposite to the first screw part 83a; a first block 84 which is provided on an outer periphery of the first screw part 83a and can move by means of rotation of the screw shaft 83; and a second block 85 which is provided on an outer periphery of the second screw part 83b and can move in a direction opposite to the direction in which the first block 84 moves by means of rotation of the screw shaft 83. The first block 84 is provided with a first inclined surface 84a, and the second block 85 is provided with a second inclined surface 85a opposite to the first inclined surface 84a. The movable core piece 82 is pressed against both the inclined surfaces 84a, 85a. By moving both blocks 84, 85 by means of the rotation of the screw shaft 83, the circumferential length of the winding core is changed.

Description

Winding device

[0001] The present invention relates to a winding device for obtaining a wound element to be built into, for example, a secondary battery or the like.

[0002] For example, a wound element used in a secondary battery such as a lithium ion battery is manufactured by winding a positive electrode sheet coated with a positive electrode active material and a negative electrode sheet coated with a negative electrode active material, which are stacked together with a separator sheet made of an insulating material interposed therebetween.

[0003] In a winding device for manufacturing a wound element, the electrode sheets and separator sheets are supplied from a roll of raw material and transported along separate transport paths to a rotatable winding core. The electrode sheets and separator sheets are then wound in a superimposed state around the winding core, and finally, the end of the separator sheet is secured with a predetermined fixing tape to obtain a wound element. The winding core may, for example, be one that extends in the direction of its rotation axis and includes multiple core pieces arranged in a direction perpendicular to the rotation axis.

[0004] The thickness of the electrode sheet supplied to the winding core may vary slightly along the longitudinal direction of the electrode sheet, and such variations in electrode sheet thickness may cause defects in the resulting wound element. For example, the resulting wound element may have a predetermined tab positioned outside its intended circumferential position. Examples of the tab include welded tabs welded to non-active material-applied portions of the electrode sheet and notched tabs formed by intermittently notching the widthwise ends of the electrode sheet.

[0005] In order to deal with the above-described variations in the thickness of the electrode sheet, a technique of providing a circumferential length changing means to a winding device has been proposed in recent years (see, for example, Patent Document 1). The circumferential length changing means changes the length of the portion of the winding core around which the electrode sheet and separator sheet are wound along the direction of rotation of the winding core (the circumferential length of the winding core). The circumferential length changing means is provided on the base end side of the winding core, and changes the circumferential length of the winding core by moving a second core piece (movable core piece) relative to a first core piece (fixed core piece) and adjusting the size of a slit formed between the two core pieces.

[0006] Also, a method is known in which a piezoelectric actuator is used as an actuator for moving a movable core piece (see, for example, Patent Document 2). The piezoelectric actuator is a stacked piezoelectric actuator having a plurality of predetermined piezoelectric elements and is provided inside the winding core. When power is supplied, the piezoelectric actuator expands and contracts along the radial direction of the winding core, thereby changing the circumferential length of the winding core.

[0007] Furthermore, a winding core with a variable circumferential length has been proposed that has a rotatable cam shaft formed with two cam portions whose distance from the rotation shaft to the outer circumferential surface is not constant, and a movable core piece is pressed against each of the two cam portions (see, for example, Patent Document 3, etc.). In this winding core, the movable core piece moves when the cam shaft is rotated, and as a result, the circumferential length of the winding core is changed.

[0008] Japanese Patent Application Laid-Open No. 2016-1624 Japanese Patent No. 6031206 Japanese Patent Application Laid-Open No. 2018-206571

[0009] In the technology described in Patent Document 1, the movable core piece is supported only at the base end of the winding core where the circumferential length changing means is located. Therefore, when a winding tightening force is applied to the movable core piece as the electrode sheet and separator sheet are wound, the movable core piece may be deformed (such as bent or twisted), and the circumferential length of the winding core may not be kept constant.

[0010] Furthermore, in the technology described in Patent Document 2, in order to ensure a sufficient reciprocating movement amount (stroke amount) of the movable core piece, it is necessary to provide an amplification mechanism in the piezo actuator. However, providing an amplification mechanism increases the size of the piezo actuator. This necessitates a relatively large winding core, making it difficult to reduce the size of the winding core.

[0011] Furthermore, because the piezoelectric actuator discharges a certain amount over time, even if it is desired to maintain the circumferential length of the winding core, it is necessary to constantly supply power to the piezoelectric actuator, which can lead to a decrease in productivity.

[0012] In addition, in the technology described in Patent Document 3, the pressing force from the movable core piece and the winding force are applied to both cam portions, which may cause the cam shaft to twist when rotated, which may interfere with the adjustment of the circumferential length of the winding core.

[0013] The present invention has been made in consideration of the above circumstances, and its object is to provide a winding device that can more reliably prevent unintended changes in the circumferential length of the winding core due to the winding tightening force, and that can also enable the winding core to be made smaller.

[0014] The following describes each of the means suitable for achieving the above object, with specific effects of the corresponding means added as necessary.

[0015] Means 1. A winding device that supplies a strip-shaped electrode sheet having an active material on its surface and a strip-shaped separator sheet made of an insulating material from a predetermined supply mechanism to a rotatable winding core, and winds the electrode sheet and the separator sheet while overlapping them as the winding core rotates around a predetermined rotation axis, wherein the winding core comprises: a fixed core piece extending in the direction of the rotation axis; a movable core piece arranged side by side with the fixed core piece in a direction perpendicular to the rotation axis and movable relative to the fixed core piece; a rotatable screw shaft that is rod-shaped extending in the direction of the rotation axis and has on its outer periphery a first screw portion with a male screw shape and a second screw portion with a male screw shape that is threaded in the opposite direction to the first screw portion; a first block that is arranged on the outer periphery of the first screw portion and is movable along the extension direction of the screw shaft as the screw shaft rotates; and a second block that is arranged on the outer periphery of the second screw portion and is movable along the extension direction of the screw shaft as the screw shaft rotates in a direction opposite to the movement direction of the first block. a pressing means for pressing the movable core piece against the first block and the second block, wherein at least one of the portion of the first block against which the movable core piece is pressed and the portion of the movable core piece against which the first block is pressed has a first inclined surface that gradually approaches the central axis of the screw shaft from one end to the other, while at least one of the portion of the second block against which the movable core piece is pressed and the portion of the movable core piece against which the second block is pressed has a second inclined surface that gradually moves away from the central axis of the screw shaft from one end to the other, and wherein the winding device is configured such that by moving the first block and the second block by rotating the screw shaft, the movable core piece is moved relative to the fixed core piece, and the length of the portion of the winding core around which the electrode sheet and the separator sheet are wound along the rotation direction of the winding core can be changed.

[0016] According to the above-mentioned means 1, by moving the movable core piece relative to the fixed core piece, it is possible to change the length along the rotation direction of the portion of the winding core around which the electrode sheet or the like is wound (hereinafter referred to as the "circumferential length of the winding core"). By changing the circumferential length of the winding core, it is possible, for example, to more reliably position the tab in a target range along the circumferential direction of the wound element.

[0017] Furthermore, according to the above-mentioned means 1, the circumferential length of the winding core can be changed by moving both blocks by rotating one screw shaft. Therefore, the circumferential length of the winding core can be changed with a relatively simple configuration, and the winding core can be made smaller.

[0018] Furthermore, the movable core piece is pressed against both blocks, and the first and second inclined surfaces are inclined in opposite directions. Therefore, even when a winding force is applied to the winding core as the electrode sheet or the like is wound, the movable core piece does not slide along the inclined surfaces, and the movable core piece can be supported in a very stable state. This more reliably prevents deformation (such as bending or twisting) of the movable core piece, and more reliably maintains a constant circumferential length of the winding core.

[0019] In addition, because the movable core piece is pressed against both blocks, the circumferential length of the winding core does not change unless the screw shaft rotates. In other words, according to the above-mentioned means 1, the circumferential length of the winding core hardly changes over time. Therefore, there is no need to carry out a special process to maintain the circumferential length of the winding core constant, such as supplying power to a specified component (for example, a piezoelectric actuator) as needed, thereby improving productivity.

[0020] Furthermore, since the movable core piece is supported by both blocks, twisting of the screw shaft when rotated is less likely to occur, which more reliably prevents problems with adjusting the circumferential length of the winding core.

[0021] In addition, because both blocks are moved by rotating the screw shaft, it is easier to move both blocks by minute distances, which allows for more precise adjustment of the circumferential length of the core.

[0022] Means 2. The winding device according to Means 1, wherein the first inclined surface is provided on the first block, and the second inclined surface is provided on the second block, and the movable core piece has a first contact surface that comes into surface contact with the first inclined surface and a second contact surface that comes into surface contact with the second inclined surface.

[0023] According to the above-mentioned means 2, the movable core piece is in surface contact with both blocks. Therefore, compared to a configuration in which the two blocks and the movable core piece are in point or line contact, the contact pressure applied to both blocks and the movable core piece can be reduced. Therefore, wear of both blocks and the movable core piece due to the movement of both blocks can be more reliably prevented. This allows for a longer lifespan of the device. Furthermore, since wear prevention can suppress the generation of wear powder, adhesion of wear powder to the electrode sheet, etc. can be effectively suppressed, which ultimately improves the quality of the wound element.

[0024] Means 3. The winding device according to Means 1, wherein the portions of the first block and the second block that are on the back side of the portions that come into contact with the movable core piece are in contact with the fixed core piece and are supported by the fixed core piece.

[0025] According to the above-mentioned means 3, both blocks that receive the force from the movable core piece can be supported by the fixed core piece, so that the circumferential length of the winding core can be more reliably kept constant.

[0026] Furthermore, the load applied to the screw shaft from one side of the movable core via both blocks can be effectively reduced, and deformation (such as bending) and damage to the screw shaft can be more reliably prevented, which can further extend the life of the device and reduce costs related to maintenance, etc.

[0027] Means 4. The winding device according to Means 1, wherein the pressing means comprises a pair of first leaf spring components provided at positions sandwiching the first block and having the function of mainly pressing the movable core piece against the first block, and a pair of second leaf spring components provided at positions sandwiching the second block and having the function of mainly pressing the movable core piece against the second block.

[0028] According to the above-mentioned means 4, the movable core piece can be pressed against both blocks in a more stable state. Furthermore, since the pressing means can be realized using simple parts, it is possible to suppress increases in costs related to the manufacturing and maintenance of the device and to further reduce the size of the winding core.

[0029] Means 5. The winding device according to Means 1, characterized in that it comprises a clamping unit that can be switched between a state in which the screw shaft is gripped and the rotation of the screw shaft is restricted, and a state in which the grip of the screw shaft is released and the rotation of the screw shaft is permitted.

[0030] According to the above-mentioned means 5, the rotation of the screw shaft can be more reliably restricted by the clamp portion, thereby more reliably keeping the circumferential length of the winding core constant.

[0031] Means 6. The winding device according to Means 1, wherein the first block is provided on one end side of the longitudinal center of the screw shaft, and the second block is provided on the other end side of the longitudinal center of the screw shaft.

[0032] According to the above-mentioned means 6, the movable core piece can be supported in a more stable state, and therefore, deformation (such as bending or twisting) of the movable core piece can be more reliably prevented.

[0033] Means 7. The winding device according to Means 1, characterized in that it has an actuator having an operating part that operates by supplying power, and also has an adjustment unit that is arranged outside the winding core, the operating part and the screw shaft each have a magnet gear, and the magnet gear is configured to transmit power from the operating part to the screw shaft in a non-contact state between the operating part and the screw shaft, thereby allowing the screw shaft to rotate.

[0034] According to the above-mentioned means 7, power can be transmitted from the operating unit to the screw shaft without contact between the operating unit and the screw shaft. This prevents the generation of wear powder when the screw shaft is rotated to adjust the circumferential length of the winding core, and ultimately more reliably prevents adverse effects of wear powder (such as device malfunctions and deterioration in the quality of the wound element due to adhesion of wear powder).

[0035] Furthermore, since there is no need to connect the operating unit and the screw shaft with a connecting part such as a belt, the circumferential length of the core can be adjusted more easily.

[0036] Means 8. The winding device according to Means 7, wherein the winding core comprises a first component part and a second component part, each of which has the fixed core piece, the movable core piece, the screw shaft, the first block, the second block, and the pressing means, and which are arranged so that the fixed core pieces face each other with a predetermined slit between them, and the adjustment unit is used in common for rotating the screw shaft in the first component part and for rotating the screw shaft in the second component part.

[0037] According to the above-mentioned means 8, the screw shafts in both components can be rotated by one adjustment unit, which makes it possible to more reliably reduce the size and simplify the device.

[0038] Means 9. The winding device according to Means 1, characterized in comprising: an input means for inputting information relating to the thickness of the electrode sheet; and a perimeter control means for controlling the relative position of the movable core piece with respect to the fixed core piece based on the information input from the input means, thereby adjusting the length of the portion of the winding core around which the electrode sheet and the separator sheet are wound, along the direction of rotation of the winding core.

[0039] Examples of input means include a means for measuring the actual thickness of the electrode sheet and then inputting information relating to that thickness into the circumference control means, and a means for reading information relating to the thickness of the electrode sheet from a barcode or IC tag attached to the original roll of the electrode sheet and containing that information, and then inputting the read information into the circumference control means.

[0040] According to the above-mentioned means 9, the circumferential length of the winding core can be automatically adjusted by the circumferential length control means based on the information relating to the thickness of the electrode sheet input by the input means. This makes it easier to adjust the circumferential length of the winding core, and allows the circumferential length to be set appropriately according to the thickness of the electrode sheet.

[0041] The technical features of the above means may be combined as appropriate. For example, the technical feature of the above means 2 may be combined with at least one of the technical features of the above means 3 to 9.

[0042] 8 is a schematic perspective view showing the general configuration of a battery element. FIG. 8 is a schematic configuration view of a winding device. FIG. 8 is a schematic configuration view of a winding section. FIG. 8 is a schematic configuration view of a winding section when a separator sheet is placed in a slit. FIG. 8 is a schematic configuration view of a winding section when a separator sheet is cut. FIG. 8 is a schematic configuration view of a winding section when winding of an electrode sheet or the like is completed. FIG. 8 is a schematic cross-sectional view of a winding core. FIG. 8 is a schematic perspective view of a first core piece. FIG. 8 is a schematic perspective view of a first core piece with most of the movable core piece omitted. FIG. 8 is a schematic plan view of a first core piece with most of the movable core piece omitted. A cross-sectional view taken along line J-J in FIG. 8. A cross-sectional view taken along line K-K in FIG. 8. A schematic perspective view of an adjustment unit and a circumferential length information acquisition device. A schematic front view showing the winding core, adjustment unit, etc. when adjusting the circumferential length of the winding core.

[0043] An embodiment will be described below with reference to the drawings. First, the structure of a lithium ion battery element as a wound element obtained by a winding device will be described.

[0044] As shown in FIG. 1 , a lithium-ion battery element 1 (hereinafter simply referred to as the "battery element 1") is manufactured by winding a positive electrode sheet 4 and a negative electrode sheet 5 in a superimposed state with two separator sheets 2 and 3 interposed therebetween. Note that a single folded separator sheet may be used instead of the two separator sheets 2 and 3. For ease of explanation, the separator sheets 2 and 3 and the electrode sheets 4 and 5 may be referred to as "various sheets 2 to 5" below. In this embodiment, the positive electrode sheet 4 and the negative electrode sheet 5 each correspond to an "electrode sheet."

[0045] The separator sheets 2 and 3 are each strip-shaped and have the same width, and are made of an insulating material such as polypropylene (PP) to prevent the different electrode sheets 4 and 5 from coming into contact with each other and causing a short circuit.

[0046] The electrode sheets 4, 5 are made of thin metal sheets and have approximately the same width as the separator sheets 2, 3. An active material is applied to both the front and back surfaces of the electrode sheets 4, 5. The positive electrode sheet 4 is, for example, an aluminum foil sheet, and a positive electrode active material (e.g., lithium manganate particles) is applied to both the front and back surfaces at a predetermined interval. The negative electrode sheet 5 is, for example, a copper foil sheet, and a negative electrode active material (e.g., activated carbon) is applied to both the front and back surfaces at a predetermined interval.

[0047] Additionally, in this embodiment, the lengths of the electrode sheets 4, 5 constituting one battery element 1 are each set to a predetermined fixed value. In this embodiment, the length of the negative electrode sheet 5 for one element is set to be slightly longer than the length of the positive electrode sheet 4 for one element so that the negative electrode sheet 5 can more reliably cover the positive electrode sheet 4.

[0048] A positive electrode tab 4a is welded to a portion of the positive electrode sheet 4 where no active material is applied, and a negative electrode tab 5a is welded to a portion of the negative electrode sheet 5 where no active material is applied. The positive electrode tab 4a protrudes from one widthwise edge of the positive electrode sheet 4, and the negative electrode tab 5a protrudes from the other widthwise edge of the negative electrode sheet 5. Ideally, the electrode tabs 4a, 5a are aligned in a row (as shown in FIG. 1 ). On the other hand, if the thickness of the wound electrode sheets 4, 5 is greater or smaller than a reference value, the positions of the electrode tabs 4a, 5a may be misaligned in the resulting battery element 1. The electrode tabs 4a, 5a may be formed between the intermittent notches in the widthwise ends of the electrode sheets 4, 5 (so-called notch tabs), for example.

[0049] To obtain a lithium-ion battery, the wound battery element 1 is placed in a cylindrical metallic battery container (case) (not shown), and the electrode tabs 4 a, 5 a are bundled together. The bundled positive electrode tabs 4 a are connected to a positive electrode terminal part (not shown), and the bundled negative electrode tabs 5 a are connected to a negative electrode terminal part (not shown), and both terminal parts are disposed so as to close both end openings of the battery container, thereby obtaining a lithium-ion battery.

[0050] Next, a winding device 10 for manufacturing the battery element 1 will be described. As shown in FIG. 2 , the winding device 10 includes a winding unit 11 for winding the various sheets 2 to 5, a positive electrode sheet supply mechanism 31 for supplying the positive electrode sheet 4 to the winding unit 11, a negative electrode sheet supply mechanism 41 for supplying the negative electrode sheet 5 to the winding unit 11, separator supply mechanisms 51 and 61 for supplying the separator sheets 2 and 3 to the winding unit 11, respectively, and a control device 91. In this embodiment, the control device 91 constitutes a "perimeter control means." The operation of various mechanisms within the winding device 10, such as the winding unit 11 and the supply mechanisms 31, 41, 51, and 61, is controlled by the control device 91.

[0051] The positive electrode sheet supply mechanism 31 includes a positive electrode sheet raw material 32 in which the positive electrode sheet 4 is wound in a roll shape. The positive electrode sheet raw material 32 is supported so as to be freely rotatable, and the positive electrode sheet 4 is pulled out from the positive electrode sheet raw material 32 as needed.

[0052] The thickness of the positive electrode sheet 4 constituting the positive electrode sheet raw roll 32 may vary for each lot of the positive electrode sheet raw roll 32 due to differences in the coating thickness of the active material, etc. Furthermore, the thickness may vary at different locations on the positive electrode sheet 4 constituting one positive electrode sheet raw roll 32. These points also apply to the negative electrode sheet 5.

[0053] The positive electrode sheet supply mechanism 31 includes a sheet insertion mechanism 71 , a sheet cutting cutter 72 , a tension applying mechanism 73 , a buffer mechanism 75 , and a thickness measuring mechanism 77 .

[0054] The sheet insertion mechanism 71 is for holding the positive electrode sheet 4 and feeding it to the winding unit 11 .

[0055] The sheet cutting cutter 72 is used to cut the positive electrode sheet 4. The cutting of the positive electrode sheet 4 is performed while the positive electrode sheet 4 is being gripped by the sheet insertion mechanism 71. The sheet cutting cutter 72 can be separated from the conveyance path of the positive electrode sheet 4 so as not to interfere with the supply of the positive electrode sheet 4 by the sheet insertion mechanism 71.

[0056] The tension applying mechanism 73 is provided with a plurality of rollers (e.g., dancer rollers) for applying tension to the positive electrode sheet 4. The operation of these rollers is controlled by a control device 91, thereby making it possible to adjust the tension applied by the tension applying mechanism 73 to the positive electrode sheet 4. In this embodiment, the tension applying mechanism 73 is configured to always apply a constant tension to the positive electrode sheet 4.

[0057] The buffer mechanism 75 is for storing the positive electrode sheet 4 having a length that constitutes at least one battery element 1 between the sheet cutting cutter 72 and the thickness measuring mechanism 77 .

[0058] The thickness measurement mechanism 77 measures the thickness of the positive electrode sheet 4 and includes a first measuring roller 77c and a second measuring roller 77d. The measuring rollers 77c and 77d are driven rollers that have the same diameter and are freely rotatable. They rotate as the positive electrode sheet 4 is conveyed. Information regarding the rotation amounts of the measuring rollers 77c and 77d is input to the control device 91. The thickness of the positive electrode sheet 4 can be measured based on the difference between the rotation amount of the first measuring roller 77c, which contacts the inner circumferential surface (curved inner surface) of the positive electrode sheet 4, and the rotation amount of the second measuring roller 77d, which contacts the outer circumferential surface (curved outer surface) of the positive electrode sheet 4. The difference between these rotation amounts increases as the positive electrode sheet 4 becomes thicker and decreases as the positive electrode sheet 4 becomes thinner. In this embodiment, the thickness measurement mechanism 77, which inputs information regarding the rotation amounts of the measuring rollers 77c and 77d (i.e., information regarding the thickness of the positive electrode sheet 4) to the control device 91, constitutes an "input means."

[0059] The negative electrode sheet supply mechanism 41 is provided, at its most upstream side, with a negative electrode sheet raw material 42 formed by winding the negative electrode sheet 5 in a roll shape. The negative electrode sheet raw material 42 is rotatably supported, and the negative electrode sheet 5 is drawn out from there as appropriate.

[0060] Further, in the middle of the conveyance path for the negative electrode sheet 5 from the negative electrode sheet raw roll 42 to the winding unit 11, a sheet insertion mechanism 71, a sheet cutting cutter 72, a tension applying mechanism 73, a buffer mechanism 75, a thickness measuring mechanism 77, and the like are provided, similar to the conveyance path for the positive electrode sheet 4. These are the same as those provided in the conveyance path for the positive electrode sheet 4, except that they function for the negative electrode sheet 5.

[0061] On the other hand, the separator supply mechanisms 51, 61 are provided with separator rolls 52, 62, each of which is formed by winding the separator sheets 2, 3 in a roll shape. The separator rolls 52, 62 are supported so as to be freely rotatable, and the separator sheets 2, 3 are pulled out from them as appropriate.

[0062] Furthermore, the separator supply mechanisms 51 and 61 are provided with a tension applying mechanism 73, similar to the electrode sheet supply mechanisms 31 and 41. This is similar to the one provided in the positive electrode sheet supply mechanism 31, except that it functions to apply tension to the separator sheets 2 and 3.

[0063] Next, the configuration of the winding unit 11 will be described. As shown in Fig. 3, the winding unit 11 includes a turret 12 consisting of two opposing disk-shaped tables rotatably mounted by a drive mechanism (not shown), two winding cores 13 and 14 spaced 180° apart in the rotational direction of the turret 12, two support rollers 15a and 15b positioned approximately 90° apart from the winding cores 13 and 14 in the rotational direction of the turret 12, a separator cutter 16, a pressure roller 17 for pressing down the various sheets 2 to 5 just before winding is completed, a tape application mechanism 18 for applying a predetermined fixing tape, an adjustment unit 19, and a circumference information acquisition device 20. The winding unit 11 also includes a removal device (not shown) for removing the battery element 1 from the winding cores 13 and 14, located around a removal position P2 (described later).

[0064] The winding cores 13 and 14 are configured to rotate around their own central axes as the rotation axis by a drive mechanism (not shown). The amount of rotation of the winding cores 13 and 14 can be detected by an encoder (not shown), and information relating to the amount of rotation is input from the encoder to the control device 91.

[0065] The winding cores 13, 14 are provided so as to be able to protrude into and retract from one of the tables constituting the turret 12 along the axial direction of the turret 12 (the depth direction of the paper in FIG. 3). When the winding cores 13, 14 protrude from one of the tables, their leading ends are inserted into a receiving tube portion 12a (see FIG. 14) provided on the other table, and the winding cores are supported in a rotatable state by both tables.

[0066] Furthermore, the winding cores 13, 14 are configured to be rotatable between a winding position P1 and a removal position P2 by rotation of the turret 12. The winding position P1 is the position where the winding cores 13, 14 are positioned when winding the various sheets 2 to 5. The removal position P2 is the position where the winding cores 13, 14 are positioned when removing the various sheets 2 to 5 (i.e., the battery element 1) after winding or when changing the circumferential length of the winding cores 13, 14. The circumferential length of the winding cores 13, 14 refers to "the length of the portion of the winding cores 13, 14 around which the various sheets 2 to 5 are wound, along the direction of rotation of the winding cores 13, 14."

[0067] The support rollers 15a and 15b are for hooking and supporting the various sheets 2 to 5 between the cores 13 and 14 that have moved to the removal position P2 and the supply mechanisms 31, 41, 51, and 61.

[0068] The separator cutter 16 is for cutting the separator sheets 2 and 3. The pressure roller 17 is for pressing down the wound various sheets 2 to 5. The tape application mechanism 18 is for applying fixing tape to the end portions of the separator sheets 2 and 3 after winding is completed.

[0069] The adjustment unit 19 is a device for changing the circumferential length of the winding cores 13, 14. The circumference information acquisition device 20 is a device for acquiring information regarding the circumferential length of the winding cores 13, 14. The configurations of the adjustment unit 19 and the circumference information acquisition device 20 will be described later.

[0070] Next, the detailed configuration of the winding cores 13, 14 in this embodiment will be described. As shown in FIG. 7 , the winding core 13 (14) is configured so that its outer peripheral surface, i.e., the portion around which the various sheets 2 to 5 are wound, forms a circular shape in a cross section perpendicular to its central axis (axis of rotation). The winding core 13 (14) includes a first core piece 131 (141) and a second core piece 132 (142). In this embodiment, the first core piece 131 (14) corresponds to the "first component" and the second core piece 132 (142) corresponds to the "second component." Note that FIG. 7 shows the first core piece 131 (141) and the second core piece 132 (142) in a particularly simplified state. The actual first core piece 131 (141) and the like include various components as shown in FIGS. 8 and 9 .

[0071] The first core piece 131 (141) and the second core piece 132 (142) extend along the rotation axis direction of the winding core 13 (14) and are arranged side by side in a direction perpendicular to the rotation axis. The first core piece 131 (141) and the second core piece 132 (142) are arranged so that the fixed core pieces 81 (described later) face each other via a predetermined slit 133 (143).

[0072] Furthermore, support portions 134 (144) are connected in series to one end of the first core piece 131 (141) (see Figure 8, not shown in Figure 9 etc.). Each support portion 134 (144) is a portion that supports the first core piece 131 (141), and in particular supports the fixed core piece 81 described below. Note that similar support portions 134 (144) are also connected in series to one end of the second core piece 132 (142). The configuration of the support portions 134, 144 can be changed as appropriate as long as they can firmly support the winding cores 13, 14.

[0073] In addition, the other end of the first core piece 131 (141) is provided with a supported portion 135 (145) that is inserted into the receiving tube portion 12a of the turret 12 to support the winding core 13 (14) by the turret 12 (see Figures 8 and 14; not shown in Figure 9, etc.). The supported portion 135 (145) is attached particularly to the other end of the fixed core piece 81, which will be described later. A similar supported portion 135 (145) is also attached to the other end of the second core piece 132 (142).

[0074] In the winding device 10 configured as described above, the various sheets 2 to 5 are wound as follows. With the separator sheets 2 and 3 stretched across the support rollers 15a and 15b, one of the winding cores 13 and 14 positioned at winding position P1 is caused to protrude from one of the tables in the turret 12, thereby placing the separator sheets 2 and 3 in the slits 133 and 143 of the winding core 13 and 14 (see FIG. 4). Then, by rotating the one of the winding cores 13 and 14 a predetermined number of times, a predetermined amount of the separator sheets 2 and 3 is wound around the winding core 13 and 14.

[0075] Next, the electrode sheets 4 and 5 are sequentially supplied to one of the winding cores 13 (14) by a sheet insertion mechanism 71, and then the winding core 13 (14) is rotated to wind the various sheets 2 to 5. Then, when a predetermined length of the various sheets 2 to 5 has been wound, the rotation of one of the winding cores 13 (14) is temporarily stopped, and the electrode sheets 4 and 5 are cut by a sheet cutting cutter 72.

[0076] Thereafter, the rotation of the turret 12 moves one of the winding cores 13 (14) around which the various sheets 2 to 5 are wound to a removal position P2. This leaves the separator sheets 2 and 3 stretched across the support rollers 15a (15b) and the like. The rotation of the turret 12 also moves the other winding core 14 (13) to a winding position P1. The next winding of the various sheets 2 to 5 is performed on this winding core 14 (13).

[0077] Next, a pressure roller 17 is brought close to one of the winding cores 13 (14) arranged at the removal position P2, and the various sheets 2 to 5 are pressed down by the pressure roller 17, and the separator sheets 2, 3 are cut by the separator cutter 16 (see FIG. 5). After that, the one of the winding cores 13 (14) is rotated to completely wind up the various sheets 2 to 5, and the fixing tape is applied to the end portions of the separator sheets 2, 3 by the tape application mechanism 18. This results in a battery element 1 that has been subjected to a winding stop process (see FIG. 6). The obtained battery element 1 is removed from the winding core 13 (14) by the removal device.

[0078] Next, we will explain the more detailed configuration of the first core piece 131, 141 and the second core piece 132, 142. In this embodiment, the first core piece 131, 141 and the second core piece 132, 142 have the same configuration, so below we will explain the configuration of the first core piece 131 (141).

[0079] As shown in Figures 8 to 12, the first core piece 131 (141) comprises a fixed core piece 81, a movable core piece 82, a screw shaft 83, a first block 84, a second block 85, a pressing mechanism 86, and a clamp 87. In this embodiment, the pressing mechanism 86 constitutes the "pressing means," and the clamp 87 constitutes the "clamp portion." Figures 9 and 10 are views showing the first core piece 131 (141) in a state where most of the movable core piece 82 is omitted. Also, Figure 11 is a cross-sectional view taken along line J-J in Figure 8, and Figure 12 is a cross-sectional view taken along line K-K in Figure 8.

[0080] The fixed core piece 81 has a rod shape extending in the direction of the rotation axis of the winding cores 13 and 14 as a whole, and includes a base portion 811 and a bush portion 812 .

[0081] The base portion 811 is the base (foundation) of the first core piece 131 (141) and is generally flat except for both ends. The flat surface of the base portion 811 located on the second core piece 132 (142) side forms the slit 133 (143) between itself and the fixed core piece 81 of the second core piece 132 (142).

[0082] A groove 811a for arranging the screw shaft 83 and both blocks 84, 85 is formed in the widthwise center of the base 811. The groove 811a extends in the direction of the rotation axis of the winding core 13 (14), and the portion of the base 811 where the groove 811a is formed serves to guide the movement of both blocks 84, 85, prevent the rotation of both blocks 84, 85, and the like.

[0083] Furthermore, a restricting protrusion 811b is formed in the center of the base portion 811 along the direction of the rotation axis of the winding core 13 (14). The restricting protrusion 811b has a role of restricting the relative movement of the movable core piece 82 with respect to the fixed core piece 81 along the width direction of the fixed core piece 81.

[0084] The bushings 812 are intended to support the screw shaft 83 in a state that allows it to rotate smoothly. One bushing 812 is provided on each end of the base 811 along the direction of the rotation axis of the winding core 13 (14). The number and arrangement of the bushings 812 may be changed as appropriate depending on the length of the winding core 13 (14) (particularly the length of the screw shaft 83).

[0085] The movable core piece 82 is generally rod-shaped and extends in the direction of the rotation axis of the winding cores 13, 14, and is arranged side by side with respect to the fixed core piece 81 in a direction perpendicular to the rotation axis of the winding core 13 (14). The movable core piece 82 includes a wound portion 821 and a regulating cylindrical portion 822.

[0086] The wound portion 821 has a curved outer surface and is a portion that constitutes the outer peripheral surface of the winding core 13 (14). In other words, the wound portion 821 is a portion around which the various sheets 2 to 5 are wound. The wound portion 821 is provided so as to cover the base portion 811, and at least the portion of the wound portion 821 around which the various sheets 2 to 5 are wound has a sufficient thickness and rigidity. Furthermore, a first contact surface 821a and a second contact surface 821b (see FIG. 11 ) are provided on the surface of the wound portion 821 that faces the base portion 811.

[0087] The first contact surface 821a is a surface that is pressed against the first block 84, and the second contact surface 821b is a surface that is pressed against the second block 85. The first contact surface 821a is shaped to gradually approach the central axis CL of the screw shaft 83 from one end to the other end, while the second contact surface 821b is shaped to gradually move away from the central axis CL of the screw shaft 83 from one end to the other end.

[0088] The restricting tube portion 822 is cylindrical and protrudes from the surface of the wound portion 821 that faces the base portion 811. The restricting protrusion 811b is inserted into the restricting tube portion 822.

[0089] The screw shaft 83 is rod-shaped and extends in the direction of the rotation axis of the winding core 13 (14), and is disposed between the core pieces 81, 82 (particularly between the base portion 811 and the wound portion 821). A first screw portion 83a and a second screw portion 83b, each having a male screw shape, are formed on the outer periphery of the screw shaft 83 at intervals along the longitudinal direction of the screw shaft 83 (see FIG. 11 ; not shown in FIG. 9 , etc.). The first screw portion 83a is formed on the outer periphery closer to one end than the longitudinal center of the screw shaft 83, while the second screw portion 83b is formed on the outer periphery closer to the other end than the longitudinal center of the screw shaft 83. The second screw portion 83b has a male screw shape that is threaded in the opposite direction to the first screw portion 83a. The pitches of the screw portions 83a, 83b are the same.

[0090] The other end of the screw shaft 83 protrudes outside the movable core piece 82, and a cylindrical magnet gear 83c is provided at the other end of the screw shaft 83. The magnet gear 83c has an outer periphery on which north and south poles are alternately arranged in the circumferential direction. When the screw shaft 83 is rotated, power is transmitted to the magnet gear 83c from the adjustment unit 19 (particularly, an operating unit 191a, which will be described later).

[0091] The first block 84 and the second block 85 move in the direction of the rotation axis of the winding core 13 (14) as the screw shaft 83 rotates, thereby changing the relative position of the movable core piece 82 with respect to the fixed core piece 81 along a direction perpendicular to the rotation axis (the direction of the white arrow in Figures 8 and 11).

[0092] The first block 84 has a female thread (not shown) that can be threaded with the first threaded portion 83a, and is provided on the outer periphery of the first threaded portion 83a. Therefore, the first block 84 is provided on one end of the threaded shaft 83 relative to its longitudinal center. On the other hand, the second block 85 has a female thread (not shown) that can be threaded with the second threaded portion 83b, and is provided on the outer periphery of the second threaded portion 83b. Therefore, the second block 85 is provided on the other end of the threaded shaft 83 relative to its longitudinal center. When the threaded shaft 83 is rotated, the first block 84 and the second block 85 move the same distance in opposite directions along the extension direction of the threaded shaft 83.

[0093] Furthermore, the first block 84 has a first inclined surface 84a that gradually approaches the center axis CL of the threaded shaft 83 from one end to the other, and a first contact surface 821a of the movable core piece 82 is in surface contact with the first inclined surface 84a (see FIG. 11). Furthermore, the second block 85 has a second inclined surface 85a that gradually moves away from the center axis CL of the threaded shaft 83 from one end to the other, and the second contact surface 821b of the movable core piece 82 is in surface contact with the second inclined surface 85a (see FIG. 11). The inclination angles of the first inclined surface 84a and the second inclined surface 85a are the same.

[0094] In this embodiment, the first block 84 and the second block 85 are configured by two blocks of the same shape. That is, one of the two blocks of the same shape is disposed on the outer periphery of the first threaded portion 83 a to configure the first block 84, and the other of the two blocks is disposed on the outer periphery of the second threaded portion 83 b in the opposite direction to the first block to configure the second block 85.

[0095] In addition, the portions of the first block 84 and the second block 85 that are on the back side of the portions that come into contact with the movable core piece 82 come into contact with the fixed core piece 81 (base portion 811), and are thereby supported by the fixed core piece 81 (base portion 811). As a result, the load applied to both blocks 84 and 85 from the movable core piece 82 side is transmitted only to the fixed core piece 81, or distributed to both the fixed core piece 81 and the screw shaft 83.

[0096] The pressing mechanism 86 is a mechanism for pressing the movable core piece 82 against the first block 84 and the second block 85. The pressing mechanism 86 includes a first leaf spring component 86a, a second leaf spring component 86b, and a locked component 86c.

[0097] The first plate spring parts 86a are provided as a pair at positions sandwiching the first block 84, and the central parts are fixed to the fixed core piece 81 (base part 811) using a predetermined screw, etc. The first plate spring parts 86a mainly have the function of pressing the movable core piece 82 against the first block 84.

[0098] On the other hand, the second leaf spring components 86b are provided as a pair at positions sandwiching the second block 85, with the central portion fixed to the fixed core piece 81 (base portion 811). The second leaf spring component 86b mainly functions to press the movable core piece 82 against the second block 85. The leaf spring components 86a and 86b may be formed of a single leaf spring or multiple stacked leaf springs.

[0099] The locked parts 86c are fixed to the movable core piece 82, and a total of eight are provided, one pair at each position corresponding to both ends of the first leaf spring part 86a and the second leaf spring part 86b. The ends of the leaf spring parts 86a and 86b are locked to the locked parts 86c, and the biasing force (force trying to return to a flat shape) generated by the leaf spring parts 86a and 86b applies a force to the movable core piece 82 in a direction pressing it toward the fixed core piece 81. As a result, the movable core piece 82 is pressed against both blocks 84 and 85.

[0100] The clamp 87 is fixed to the other end of the fixed core piece 81 and is a component for switching between a state in which rotation of the screw shaft 83 is restricted and a state in which rotation of the screw shaft 83 is permitted. The clamp 87 has a predetermined spring 87a, and the biasing force of the spring 87a basically enables the clamp 87 to maintain a state in which the screw shaft 83 is gripped and rotation of the screw shaft 83 is restricted (i.e., a closed state). However, the clamp 87 has a predetermined lever portion 87b, and by pressing the lever portion 87b, the clamp 87 can release the grip on the screw shaft 83 and enter a state in which rotation of the screw shaft 83 is permitted (i.e., an open state).

[0101] Next, the adjustment unit 19 will be described. Only one adjustment unit 19 is provided outside the winding cores 13, 14 (i.e., separate from the winding cores 13, 14), corresponding to the winding core 13 (14) positioned at the removal position P2. The adjustment unit 19 can be moved back and forth by a driving means (not shown) between an approach position where it approaches the winding core 13 (14) positioned at the removal position P2, and a retracted position where it is separated from the winding core 13 (14) (see FIG. 3). As shown in FIG. 13, the adjustment unit 19 includes an actuator 191 that functions as a power source for rotating the screw shaft 83, and a lever pusher 192 for pressing the lever portion 87b.

[0102] The actuator 191 is configured with, for example, a servo motor or the like, and is electrically connected to a power supply (not shown). The actuator 191 includes an operating part 191a that can rotate when power is supplied from the power supply, and a magnet gear 191b fixed to the operating part 191a. The magnet gear 191b has a configuration similar to that of the magnet gear 83c, and rotates together with the operating part 191a.

[0103] The lever pusher 192 is rod-shaped, and presses the lever portion 87b with its tip when the adjustment unit 19 is placed in the approach position.

[0104] When changing the circumferential length of the winding core 13 (14), the adjustment unit 19 moves from the retracted position to the approach position, thereby pressing the lever portion 87b with the lever pusher 192 and positioning the magnet gear 191b to the side of the magnet gear 83c on the winding core 13 (14) side (see FIG. 14). In other words, by moving from the retracted position to the approach position, the adjustment unit 19 makes the screw shaft 83 rotatable and enables power to be transmitted from the operating portion 191a to the screw shaft 83.

[0105] Next, the circumference information acquisition device 20 will be described. The circumference information acquisition device 20 is configured to obtain information regarding the circumference of the winding core 13 (14) by detecting the actual position of the movable core piece 82 when changing the circumference of the winding core 13 (14). The circumference information acquisition device 20 can be moved back and forth by a driving means (not shown) between an approach position where it approaches the winding core 13 (14) positioned at the removal position P2 and a retracted position where it is separated from the winding core 13 (14) (see FIG. 3). The circumference information acquisition device 20 is positioned at the approach position when acquiring information regarding the position of the movable core piece 82. The circumference information acquisition device 20 includes a light-emitting unit 20b and a light-receiving unit 20c (see FIG. 14). Two pairs of the light-emitting unit 20b and the light-receiving unit 20c are provided at an interval along the longitudinal direction of the winding core 13 (14).

[0106] The light-emitting unit 20b is provided at a position opposite to the light-receiving unit 20c, and irradiates a laser beam LA of a predetermined width toward the light-receiving unit 20c. When the circumference information acquisition device 20 is placed at the approach position, a portion of the irradiated laser beam LA is blocked by the movable core piece 82, and the width of the laser beam that reaches the light-receiving unit 20c varies depending on the position of the movable core piece 82.

[0107] The light receiving unit 20c includes a predetermined light receiving element that receives the laser beam LA emitted from the light projecting unit 20b and detects information relating to the width of the received laser beam LA. In this embodiment, the information relating to the width of the received laser beam LA corresponds to the circumferential length of the winding cores 13, 14. The circumferential length information acquiring device 20 outputs a received light amount signal corresponding to the width of the laser beam LA received by the light receiving unit 20c to the control device 91.

[0108] Next, we will explain the configuration of the control device 91. The control device 91 is made up of a computer system including a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a ROM (Read Only Memory) that stores various programs and fixed value data, a RAM (Random Access Memory) that temporarily stores various data when various arithmetic processing is executed, and peripheral circuits for these.

[0109] The control device 91 controls the timing of starting and stopping the supply of the electrode sheets 4, 5 to the winding unit 11, the rotation of the winding cores 13, 14, the operation of the adjustment unit 19 and the circumference information acquisition device 20, and the power supply to the actuator 191. For example, the control device 91 is configured to receive information on the payout amounts of the electrode sheets 4, 5 from an encoder (not shown), and stops the payout (supply) of the electrode sheets 4, 5 when the payout amounts of the electrode sheets 4, 5 each reach a predetermined value.

[0110] Based on the input information regarding the rotation amounts of the measuring rollers 77c, 77d, the control device 91 measures the thickness of the entire longitudinal area of ​​the electrode sheets 4, 5 for one element that passes between the measuring rollers 77c, 77d from the start to the end of feeding of the electrode sheets 4, 5. This electrode sheet 4, 5 for one element that passes between the measuring rollers 77c, 77d is the one to be wound next. A table showing the correspondence between the difference in the rotation amounts of the measuring rollers 77c, 77d and the thickness of the electrode sheets 4, 5 is stored in advance in the control device 91, and the thickness of the electrode sheets 4, 5 can be obtained by referring to this table.

[0111] In addition, the control device 91 is capable of acquiring the position of the movable core piece 82 based on the received light amount signal input from the circumference information acquisition device 20 .

[0112] Furthermore, the control device 91 controls the winding cores 13 (14), the adjustment unit 19, the circumference information acquisition device 20, etc. so as to change the circumference of the winding cores 13 (14) in accordance with the measured thickness of the electrode sheets 4 (5) (in this embodiment, the average value of the thickness of the electrode sheets 4 (5)). More specifically, the control device 91 first calculates the target position of the movable core piece 82 in accordance with the measured thickness of the electrode sheets 4 (5) (in this embodiment, the average value of the thickness of the electrode sheets 4 (5)) based on a target circumference calculation formula stored in advance.

[0113] The target position is the position of the movable core piece 82 that is considered optimal for suppressing misalignment of the electrode tabs 4a, 5a in relation to the electrode sheets 4, 5 whose thicknesses have been measured. By positioning each of the movable core pieces 82 of the first core piece 131 (141) and the second core piece 132 (142) at their respective target positions, the circumferential length of the winding core 13 (14) becomes the circumferential length (target circumferential length) that is considered optimal for suppressing misalignment of the electrode tabs 4a, 5a. If the measured thicknesses of the electrode sheets 4, 5 are relatively large, the target circumferential lengths of the winding cores 13, 14 are set to be relatively small. On the other hand, if the measured thicknesses of the electrode sheets 4, 5 are relatively small, the target circumferential lengths of the winding cores 13, 14 are set to be relatively large. Note that the target circumferential length is applied to one of the winding cores 13, 14 that is used to wind the electrode sheets 4, 5 whose thicknesses have been measured.

[0114] Next, the control device 91 adjusts the positions of the movable core segments 82 in the first core segment 131 (141) and the second core segment 132 (142) based on the calculated target positions. That is, the control device 91 first inserts the end of the winding core 13 (14) arranged at the removal position P2 into the receiving tube portion 12a, thereby stably supporting the winding core 13 (14). Then, the control device 91 rotates the winding core 13 (14) so ​​that the first core segment 131 (141) is in a predetermined position (in this embodiment, a state in which the first core segment 131 (141) is positioned below the second core segment 132 (142)).

[0115] Next, the adjustment unit 19 and the circumference information acquisition device 20 are moved to the close position (see FIG. 14). This allows power to be transmitted from the operating part 191a to the screw shaft 83 via the magnet gears 83c and 191b, with the operating part 191a and the screw shaft 83 in a non-contact state. Furthermore, the lever part 87b is pressed by the lever pusher 192, allowing rotation of the screw shaft 83. Furthermore, the control device 91 can acquire the position of the movable core piece 82 using the circumference information acquisition device 20.

[0116] The control device 91 then acquires the position of the movable core piece 82 using the circumference information acquisition device 20, and supplies power to the actuator 191 until the position reaches the target position. More specifically, by supplying power to the actuator 191, power is transmitted from the operating unit 191a to the screw shaft 83 via the magnet gears 83c and 191b, causing the screw shaft 83 to rotate. As the screw shaft 83 rotates, the first block 84 and the second block 85 gradually move in opposite directions. As a result, the relative position of the movable core piece 82 with respect to the fixed core piece 81 is adjusted, and the movable core piece 82 is finally positioned at the target position. After adjusting the position of the movable core piece 82, the adjustment unit 19 and the circumference information acquisition device 20 return to their original retracted positions.

[0117] Furthermore, following the position adjustment of the movable core piece 82 in the first core piece 131 (141), a similar position adjustment is performed in the second core piece 132 (142). That is, after rotating the winding cores 13 and 14 by 180°, the position adjustment of the movable core piece 82 described above is performed for the second core piece 132 (142). By adjusting the positions of the movable core pieces 82 in the first core piece 131 (141) and the second core piece 132 (142), the circumferential length of the winding core 13 (14) becomes the target circumferential length.

[0118] As described above in detail, according to this embodiment, the circumferential length of the winding cores 13, 14 can be changed by moving the movable core piece 82 relative to the fixed core piece 81. This makes it possible, for example, to more reliably position the tabs 4 a, 5 a within a target range along the circumferential direction of the battery element 1.

[0119] Furthermore, the circumferential lengths of the winding cores 13, 14 can be changed by moving both blocks 84, 85 through the rotation of one screw shaft 83. Therefore, the circumferential lengths of the winding cores 13, 14 can be changed with a relatively simple configuration, and the winding cores 13, 14 can be made smaller.

[0120] Furthermore, the movable core piece 82 is pressed against both blocks 84, 85, and the inclination directions of the first inclined surface 84a and the second inclined surface 85a are opposite. Therefore, even when a winding force is applied to the winding cores 13, 14 as the various sheets 2 to 5 are wound, the movable core piece 82 does not slide along the inclined surfaces 84a, 85a, and the movable core piece 82 can be supported in a very stable state. Therefore, deformation (such as bending or twisting) of the movable core piece 82 can be more reliably prevented, and the circumferential lengths of the winding cores 13, 14 can be more reliably maintained constant.

[0121] In addition, because the movable core piece 82 is pressed against both blocks 84, 85, the circumferential lengths of the winding cores 13, 14 do not change unless the screw shaft 83 rotates. Therefore, in this embodiment, the circumferential lengths of the winding cores 13, 14 do not change over time. This eliminates the need to perform special steps to maintain the circumferential lengths of the winding cores 13, 14 constant, such as supplying power to certain components as needed, thereby improving productivity.

[0122] Furthermore, since the movable core piece 82 is supported by both blocks 84, 85, it is possible to make it more difficult for the screw shaft 83 to twist when the screw shaft 83 is rotated. This makes it possible to more reliably prevent problems from occurring in adjusting the circumferential lengths of the winding cores 13, 14.

[0123] In addition, because the blocks 84 and 85 are moved by the rotation of the screw shaft 83, it is easier to move the blocks 84 and 85 by minute distances, which allows the circumferential lengths of the cores 13 and 14 to be adjusted more precisely.

[0124] Furthermore, in this embodiment, since the movable core piece 82 is in surface contact with both blocks 84, 85, the contact pressure applied to both blocks 84, 85 and the movable core piece 82 can be reduced compared to a configuration in which the blocks 84, 85 and the movable core piece 82 are in point or line contact. This more reliably prevents wear of both blocks 84, 85 and the movable core piece 82 due to movement of the blocks 84, 85. This allows for a longer lifespan of the winding device 10. Furthermore, since wear prevention can suppress the generation of wear powder, adhesion of wear powder to the various sheets 2 to 5 can be effectively suppressed, thereby improving the quality of the battery element 1.

[0125] Furthermore, the portions of both blocks 84, 85 that are behind the portions that contact the movable core piece 82 contact the fixed core piece 81 and are supported by the fixed core piece 81. Therefore, both blocks 84, 85 that receive force from the movable core piece 82 can be more reliably supported, and ultimately the circumferential lengths of the winding cores 13, 14 can be more reliably kept constant. Furthermore, the load applied to the screw shaft 83 from the movable core piece 82 side via both blocks 84, 85 can be effectively reduced, so deformation (such as bending) and damage to the screw shaft 83 can be more reliably prevented. As a result, the life of the winding device 10 can be further extended and costs related to maintenance can be reduced.

[0126] In addition, the pressing mechanism 86 can more stably press the movable core piece 82 against both blocks 84, 85. Furthermore, since the pressing mechanism 86 is composed of simple parts, it is possible to suppress increases in costs related to the manufacturing and maintenance of the winding device 10 and further reduce the size of the winding cores 13, 14.

[0127] Additionally, the clamp 87 can more reliably restrict rotation of the screw shaft 83, so that the circumferential lengths of the cores 13, 14 can be kept constant even more reliably.

[0128] Furthermore, the first block 84 is provided on one end side of the longitudinal center of the screw shaft 83, and the second block 85 is provided on the other end side of the longitudinal center of the screw shaft 83. Therefore, the movable core piece 82 can be supported in a more stable state, and deformation (such as bending or twisting) of the movable core piece 82 can be more reliably prevented.

[0129] Furthermore, by using the magnet gears 83c and 191b, power can be transmitted from the operating unit 191a to the screw shaft 83 without contact between the operating unit 191a and the screw shaft 83. This prevents wear powder from being generated when the screw shaft 83 is rotated to adjust the circumferential length of the winding cores 13 and 14, thereby more reliably preventing adverse effects of wear powder (such as device malfunctions and deterioration in the quality of the battery element 1 due to adhesion of wear powder). In addition, because there is no need to connect the operating unit 191a and the screw shaft 83 with a connecting part such as a belt, adjustment of the circumferential length of the winding cores 13 and 14 can be made more easily.

[0130] In addition, the adjustment unit 19 is used in common for rotating the screw shaft 83 in the first core piece 131 (141) and for rotating the screw shaft 83 in the second core piece 132 (142). Therefore, the winding device 10 can be more reliably made smaller and simpler.

[0131] Furthermore, the control device 91 can automatically adjust the circumferential lengths of the winding cores 13, 14 based on information relating to the thickness of the electrode sheets 4, 5 input by the thickness measurement mechanism 77. This makes it easier to adjust the circumferential lengths of the winding cores 13, 14, and allows them to be set to appropriate circumferential lengths according to the thicknesses of the electrode sheets 4, 5.

[0132] The present invention is not limited to the above-described embodiment, and may be implemented as follows: Of course, other applications and modifications not exemplified below are also possible.

[0133] (a) In the above embodiment, the first block 84 is provided with the first inclined surface 84a, but the first inclined surface may be provided on the portion of the movable core piece 82 that is pressed against the first block 84. For example, the first block 84 may be a rectangular block without the first inclined surface 84a, or a block whose contact portion with the movable core piece 82 is formed by a rotatable roller, and the first inclined surface of the movable core piece 82 (for example, an inclined surface having the same shape as the first contact surface 821a in the above embodiment) may be configured to be pressed against the first block 84. The second inclined surface 85a may also be configured in a similar manner.

[0134] Furthermore, the first inclined surface may be provided on both the first block 84 and the movable core piece 82 , and the second inclined surface may be provided on both the second block 85 and the movable core piece 82 .

[0135] (b) In the above embodiment, the thickness measurement mechanism 77 serving as the "input means" is composed of measurement rollers 77c, 77d that sandwich the electrode sheets 4, 5, and acquires information about the amount of rotation of the measurement rollers 77c, 77d as information about the thickness of the electrode sheets 4, 5. In contrast, the thickness measurement mechanism may include a roller whose position varies depending on the thickness of the electrode sheets 4, 5, and a sensor capable of measuring the position of the roller (for example, a displacement sensor that irradiates the roller with a laser), and acquire information about the thickness of the electrode sheets 4, 5 based on the measurement results from the sensor.

[0136] Furthermore, the "input means" may be a means for inputting information relating to the thickness of the electrode sheets 4, 5 measured in advance into the control device 91 (for example, a reading device for reading information relating to the thickness of the electrode sheets 4, 5 from a barcode or IC tag attached to the original roll of the electrode sheets 4, 5 and carrying the information). Of course, the "input means" may also be a device for manually inputting numerical information (for example, a keyboard or a touch panel).

[0137] (c) In the above embodiment, the adjustment unit 19 and the circumference information acquisition device 20 are provided separately, but they may also be integrated.

[0138] (d) In the above embodiment, the first core piece 131 (141) and the second core piece 132 (142) each have a function related to changing the circumferential length of the winding core 13 (14) (i.e., a function to adjust the relative position of the movable core piece 82 with respect to the fixed core piece 81), but it is also possible to configure only one of the first core piece 131 (141) and the second core piece 132 (142) to have this function.

[0139] (e) In the above embodiment, the winding cores 13 and 14 have a circular cross section, but the shape of the winding cores may be changed as appropriate. For example, the winding cores may be configured to have an oval or flattened cross section perpendicular to the rotation axis of the winding cores.

[0140] (f) In the above embodiment, the pressing mechanism 86 having the leaf spring parts 86a, 86b and the like is given as the "pressing means." However, the "pressing means" may also be, for example, a magnet.

[0141] (g) In the above embodiment, when the circumferential length of the winding core 13 (14) is changed, the position of the movable core piece 82 is acquired and power is supplied to the actuator 191 until this position becomes the target position. However, it is also possible to acquire the position of the movable core piece 82 in advance before changing the circumferential length of the winding core 13 (14), calculate the required movement amount of the movable core piece 82 based on this acquired position, and supply power to the actuator 191 so that the movable core piece 82 moves by this required movement amount.

[0142] (h) In the above embodiment, the winding unit 11 is configured to include two winding cores 13, 14, but it may also be configured to include one winding core or three or more winding cores.

[0143] (i) In the above embodiment, the battery element 1 of a lithium ion battery is manufactured by the winding device 10, but the wound element manufactured by the winding device 10 is not limited to this, and for example, the wound element of an electrolytic capacitor may be manufactured.

[0144] (j) The materials of the separator sheets 2, 3 and the electrode sheets 4, 5 are not limited to those in the above embodiment and may be changed as appropriate. Of course, the active material applied to the electrode sheets 4, 5 may also be changed.

[0145] (k) In the above embodiment, the circumferential length of the winding core 13 (14) is changed for the purpose of aligning the electrode tabs 4 a, 5 a, but it may be changed for other purposes. For example, the circumferential length of the winding core 13 (14) may be changed to accommodate changes in the size of the battery element 1 or to keep the outer diameter of the battery element 1 constant.

[0146] 1...Lithium ion battery element (wound element), 2, 3...Separator sheet, 4...Positive electrode sheet (electrode sheet), 5...Negative electrode sheet (electrode sheet), 10...Winding device, 13, 14...Winding core, 19...Adjustment unit, 77...Thickness measurement mechanism (input means), 81...Fixed core piece, 82...Moving core piece, 83...Screw shaft, 83a...First screw portion, 83b...Second screw portion, 83c...Magnet gear, 84...First block, 84a...First inclined surface, 85...Second block lock, 85a...second inclined surface, 86...pressure mechanism (pressure means), 86a...first leaf spring part, 86b...second leaf spring part, 87...clamp (clamp portion), 91...control device (circumferential length control means), 131, 141...first core piece (first component part), 132, 142...second core piece (second component part), 133, 143...slit, 191...actuator, 191a...operating part, 191b...magnetic gear, 821a...first contact surface, 821b...second contact surface.

Claims

1. A winding device that supplies a strip-shaped electrode sheet having an active material on its surface and a strip-shaped separator sheet made of an insulating material from a predetermined supply mechanism to a rotatable winding core, and winds the electrode sheet and the separator sheet while overlapping them as the winding core rotates around a predetermined rotation axis, wherein the winding core comprises: a fixed core piece extending in the direction of the rotation axis; a movable core piece arranged side by side with the fixed core piece in a direction perpendicular to the rotation axis and movable relative to the fixed core piece; a rotatable screw shaft that is rod-shaped extending in the direction of the rotation axis and has on its outer periphery a first screw portion with a male screw shape and a second screw portion with a male screw shape that is threaded in the opposite direction to the first screw portion; a first block that is arranged on the outer periphery of the first screw portion and is movable in the extension direction of the screw shaft as the screw shaft rotates; and a second block that is arranged on the outer periphery of the second screw portion and is movable in the extension direction of the screw shaft as the screw shaft rotates, in a direction opposite to the movement direction of the first block. a pressing means for pressing the movable core piece against the first block and the second block, wherein at least one of the portion of the first block against which the movable core piece is pressed and the portion of the movable core piece against which the first block is pressed has a first inclined surface that gradually approaches the central axis of the screw shaft from one end to the other, while at least one of the portion of the second block against which the movable core piece is pressed and the portion of the movable core piece against which the second block is pressed has a second inclined surface that gradually moves away from the central axis of the screw shaft from one end to the other, and wherein the winding device is configured such that by moving the first block and the second block by rotating the screw shaft, the movable core piece is moved relative to the fixed core piece, and the length of the portion of the winding core around which the electrode sheet and the separator sheet are wound along the rotation direction of the winding core can be changed.

2. A winding device as described in claim 1, characterized in that the first inclined surface is provided on the first block and the second inclined surface is provided on the second block, and the movable core piece has a first contact surface that makes surface contact with the first inclined surface and a second contact surface that makes surface contact with the second inclined surface.

3. A winding device as described in claim 1, characterized in that the portions of the first block and the second block that are on the back side of the portions that contact the movable core piece are in contact with the fixed core piece and are supported by the fixed core piece.

4. The winding device described in claim 1, characterized in that the pressing means comprises a pair of first leaf spring components arranged at positions sandwiching the first block and having the main function of pressing the movable core piece against the first block, and a pair of second leaf spring components arranged at positions sandwiching the second block and having the main function of pressing the movable core piece against the second block.

5. A winding device as described in claim 1, characterized in that it is provided with a clamping section that can be switched between a state in which it grips the screw shaft and restricts its rotation, and a state in which it releases its grip on the screw shaft and allows its rotation.

6. A winding device as described in claim 1, characterized in that the first block is provided on one end side of the longitudinal center of the screw shaft, and the second block is provided on the other end side of the longitudinal center of the screw shaft.

7. A winding device as described in claim 1, characterized in that it has an actuator equipped with an operating part that operates when supplied with power, and also has an adjustment unit that is placed outside the winding core, and the operating part and the screw shaft each have a magnetic gear, and the magnetic gear is configured to transmit power from the operating part to the screw shaft in a non-contact state between the operating part and the screw shaft, thereby rotating the screw shaft.

8. The winding device described in claim 7, characterized in that the winding core has the fixed core piece, the movable core piece, the screw shaft, the first block, the second block, and the pressing means, and is provided with a first component part and a second component part arranged so that the fixed core pieces face each other via a predetermined slit, and the adjustment unit is used commonly for rotating the screw shaft in the first component part and for rotating the screw shaft in the second component part.

9. A winding device as described in claim 1, characterized in that it comprises an input means for inputting information relating to the thickness of the electrode sheet, and a circumference control means for controlling the relative position of the movable core piece with respect to the fixed core piece based on the information input from the input means, thereby adjusting the length of the portion of the winding core around which the electrode sheet and the separator sheet are wound along the rotational direction of the winding core.

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