CN118044018A

CN118044018A - Winding core and winding device

Info

Publication number: CN118044018A
Application number: CN202280063332.7A
Authority: CN
Inventors: 高濑辰己; 深津健太; 岩崎文子
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 2022-02-04
Filing date: 2022-02-04
Publication date: 2024-05-14
Also published as: WO2023148933A1; JPWO2023148933A1

Abstract

The winding core of the embodiment extends along a first central axis as a rotation center. The winding core has: a pair of outer peripheral surfaces formed with a predetermined radius of curvature, and a pair of corners extending along the first central axis at circumferentially symmetrical positions. A band-like material is wound around the outer peripheral surface of the winding core.

Description

Winding core and winding device

Technical Field

Embodiments of the present invention relate to a winding core and a winding device.

Background

A winding apparatus is known that winds a plurality of foil-shaped strips in a state where the materials are superimposed on each other to produce a wound body. The winding device is provided with a winding core. The winding device winds the material of the wound body around the winding core by rotating the winding core, thereby completing the wound body. The shape of such a winding core is roughly classified into a circular shape and a non-circular shape, and has advantages and disadvantages.

For example, when the winding core having a circular shape rotates, the winding speed can be made high because the speed does not substantially need to be variable. However, the material at the innermost periphery is highly likely to be loosened after completion of winding, and the material at the innermost periphery is highly likely to be creased after punching the wound body after completion of winding.

In the case of a non-circular winding core, although the material on the innermost circumference is less likely to be loosened, the speed of acceleration and deceleration at the time of rotation of the winding core is increased due to occurrence of a fluctuation in the foil speed. Therefore, it is necessary to control the rotation of the winding core to a non-circular winding core, thereby suppressing the fluctuation of the foil speed and increasing the winding speed.

Therefore, a winding core is demanded which can suppress the relaxation of the innermost circumference and reduce the acceleration and deceleration.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2017-091667

Patent document 2: japanese patent laid-open No. 2021-160895

Disclosure of Invention

First, the technical problem to be solved

The invention aims to solve the technical problems that: provided are a winding core and a winding device capable of suppressing the relaxation of an innermost material and reducing the acceleration and deceleration during rotation.

(II) technical scheme

Drawings

Fig. 1 is an explanatory diagram schematically showing a configuration of an example of a winding device according to the embodiment.

Fig. 2 is a block diagram showing an example of a control structure of the winding device according to the embodiment.

Fig. 3 is a cross-sectional view schematically showing the structure of a winding core of the winding device according to the embodiment.

Fig. 4 is an explanatory view schematically showing an example of a wound body manufactured from the winding core according to the embodiment.

Fig. 5 is an explanatory diagram schematically showing the structure of the winding core according to the embodiment.

Fig. 6 is a flowchart showing an example of a method for manufacturing a winding body using the winding device according to the embodiment.

Fig. 7 is a cross-sectional view schematically showing the structure of the winding core of comparative example 1.

Fig. 8 is a cross-sectional view schematically showing the structure of the winding core of comparative example 2.

Fig. 9 is a cross-sectional view schematically showing the structure of the winding core of comparative example 3.

Fig. 10 is a cross-sectional view schematically showing the structure of the winding core of comparative example 4.

Fig. 11 is an explanatory view schematically showing an example of a wound body manufactured from the winding core of comparative example 1.

Fig. 12 is an explanatory diagram showing an example of material winding using the winding core according to the embodiment.

Fig. 13 is an explanatory view showing an example of material winding using the winding core of comparative example 2.

Fig. 14 is an explanatory diagram showing a relationship between a reel speed and a foil speed with respect to a reel angle of the winding core according to the embodiment.

Fig. 15 is an explanatory diagram showing a relationship between a reel speed and a foil speed with respect to a reel angle of the winding core of comparative example 2.

Fig. 16 is an explanatory diagram showing a relationship between a reel speed and a foil speed with respect to a reel angle of the winding core according to the embodiment.

Fig. 17 is an explanatory diagram showing a relationship between a reel speed and a foil speed with respect to a reel angle of the winding core of comparative example 2.

Fig. 18 is an explanatory diagram showing evaluation test results of the winding cores of the embodiment and the winding cores of comparative example 1.

Fig. 19 is an explanatory diagram showing a state of material of the innermost circumference of a wound body manufactured by the winding core of the embodiment.

Fig. 20 is an explanatory diagram showing a state of material of the innermost circumference of the wound body manufactured from the winding core of comparative example 1.

Fig. 21 is an exploded perspective view showing an example of a nonaqueous electrolyte battery according to an embodiment.

Fig. 22 is a partially developed perspective view showing the structure of an electrode group used in the nonaqueous electrolyte battery according to the embodiment.

Fig. 23 is a flowchart showing a process for manufacturing the secondary battery according to the embodiment.

Fig. 24 is a cross-sectional view schematically showing the structure of a winding core according to another embodiment.

Detailed Description

The following describes the structure of the winding device 1 and the winding core 40 according to the embodiment with reference to the drawings. In the drawings, the structure is appropriately enlarged, reduced, or omitted for convenience of explanation.

Fig. 1 is an explanatory diagram schematically showing an example of a structure of a winding device 1 according to the embodiment, and fig. 2 is a block diagram showing an example of a control structure of the winding device 1. Fig. 3 is a cross-sectional view schematically showing the structure of the winding core 40 used in the winding device 1. Fig. 4 is an explanatory diagram schematically showing an example of the wound body 100 manufactured by using the winding core 40. Fig. 5 is an explanatory diagram schematically showing the structure of the winding core 40.

As shown in fig. 1, a winding apparatus 1 is an apparatus for manufacturing a roll 100 by winding a plurality of strip materials (foils) with a winding core 40 in a state where the materials are overlapped. With respect to the roll 100 manufactured with the winding apparatus 1, at least one of the plurality of band-like materials is a foil formed of a metal material.

First, a specific example of the roll 100 manufactured by the winding apparatus 1 will be described. The winding device 1 winds a plurality of band-like materials (band-like bodies) to manufacture a wound body 100. As an example, the wound body 100 can be used for an electrode group used in a secondary battery such as a lithium ion battery. The following examples are described in this embodiment: the winding device 1 uses the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 as four band-shaped materials to manufacture a wound body 100 for an electrode group of a secondary battery.

Fig. 22 shows an example of the electrode group 155 using the wound body 100, and the wound body 100 is formed by the winding device 1 of the embodiment of fig. 1. As shown in fig. 22, in the winding device 1, four strip materials are wound in a state where the four strip materials are overlapped to form an electrode group 155. The winding device 1 winds the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 in a state where the four band-shaped materials, i.e., the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 are sequentially stacked. In the electrode group 155, a positive electrode 156 is formed by the positive electrode sheet 101, and a negative electrode 157 is formed by the negative electrode sheet 103. In addition, in the electrode group 155, a separator layer that electrically insulates between the positive electrode 156 and the negative electrode 157 is formed by the separators 102, 104.

The electrode group 155 may be configured such that the negative electrode sheet 103 is on the inner peripheral side when wound and the positive electrode sheet 101 is on the outer peripheral side when wound, or may be configured such that the positive electrode sheet 101 is on the inner peripheral side when wound and the negative electrode sheet 103 is on the outer peripheral side when wound.

The positive electrode sheet 101 is an electrode sheet forming a positive electrode of the secondary battery. The positive electrode sheet 101 is an example of a belt-like material. The positive electrode sheet 101 is a positive electrode current collector in a strip shape. The positive electrode sheet 101 is formed of, for example, aluminum foil or aluminum alloy foil. The positive electrode sheet 101 has a positive electrode active material-containing layer provided on at least one surface. The positive electrode active material-containing layer contains a positive electrode active material.

The negative electrode sheet 103 is an electrode sheet forming a negative electrode of the secondary battery. The negative electrode sheet 103 is an example of a band-shaped material. The negative electrode sheet 103 is a negative electrode current collector in a strip shape. The negative electrode sheet 103 is formed of, for example, copper foil. The negative electrode sheet 103 may be formed of aluminum foil or aluminum alloy foil. The negative electrode sheet 103 has a negative electrode active material-containing layer provided on at least one surface. The anode active material-containing layer contains an anode active material.

The separators 102 and 104 are disposed between the positive electrode sheet 101 and the negative electrode sheet 103. Spacers 102, 104 constitute an insulating layer. Therefore, the separators 102 and 104 serve as a separator 158 for electrically insulating the positive electrode 156 from the negative electrode 157 in the electrode group 155 manufactured by winding the positive electrode sheet 101 and the negative electrode sheet 103. Instead of the separators 102 and 104, a solid electrolyte-containing layer may be formed integrally with one of the positive electrode sheet 101 and the negative electrode sheet 103. In this case, in the electrode group manufactured, the solid electrolyte-containing layer electrically insulates between the positive electrode and the negative electrode.

Next, the winding device 1 will be described. As shown in fig. 1, the winding device 1 includes, for example: four supply units 5 to 8, four conveying units 11 to 14, a winding core 40, a motor 50, an adjusting mechanism 60, a cutting device 70, and a control device 80.

For example, two reels 10 are disposed in each of the supply units 5 and 6, and for example, one reel 10 is disposed in each of the supply units 7 and 8. The reel 10 holds a roll of a raw material in a roll shape, which is formed by winding a band-like material. Each of the reels 10 winds a corresponding one of the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 in a roll. In the supply unit 5, the negative electrode sheet 103 is fed from one of the two reels 10 to the transport unit 11, and in the supply unit 6, the positive electrode sheet 101 is fed from one of the two reels 10 to the transport unit 12. In the supply unit 7, the separator 102 is fed from the roll 10 to the transport unit 13, and in the supply unit 8, the separator 104 is fed from the roll 10 to the transport unit 14. The supply units 5 to 8 intermittently feed out the corresponding one of the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 to the corresponding one of the conveyance units 11 to 14. The positive electrode sheet 101, separator 102, negative electrode sheet 103, and separator 104 are fed out by a predetermined length in the longitudinal direction along the pair of long edges in one feeding.

The conveying sections 11 to 14 form a conveying path. The transport unit 11 transports the negative electrode sheet 103 fed from the supply unit 5 to the winding core 40 via a transport path, and the transport unit 12 transports the positive electrode sheet 101 fed from the supply unit 6 to the winding core 40 via a transport path. The transport unit 13 transports the separator 102 fed from the supply unit 7 to the winding core 40 through a transport path, and the transport unit 14 transports the separator 104 fed from the supply unit 8 to the winding core 40 through a transport path. In each of the conveying sections (conveying paths) 11 to 14, the conveying direction in which the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 are conveyed, that is, the direction toward the winding core 40 is set to the downstream side. In each of the conveying units 11 to 14, a direction opposite to the conveying direction, that is, a direction toward a corresponding one of the supply units 5 to 8 is set as an upstream side. In the example of fig. 1, the arrow X1 side is the downstream side of the conveying section 11, and the arrow X2 side is the upstream side of the conveying section 11.

More than one guide roller 15 is disposed in each of the conveying sections (conveying paths) 11 to 14, and in the example of fig. 1, a plurality of guide rollers 15 are disposed in each of the conveying sections 11 to 14. The corresponding one of the positive electrode sheet 101, separator 102, negative electrode sheet 103, and separator 104 is guided to the winding core 40 by guide rollers 15 in the four conveying paths of the conveying sections 11 to 14. The number and arrangement of the guide rollers 15 in each of the conveying units 11 to 14 are not limited to the example of fig. 1, and may be appropriately changed according to the arrangement of the supply units 5 to 8, the arrangement of the winding cores 40, and the like.

The conveying sections 11 and 12 are provided with a platen roller 16 and detecting sections 17 and 18, respectively. The pressing roller 16 is formed of rubber, for example. The negative electrode sheet 103 is conveyed by being sandwiched between the pressing roller 16 of the conveying section 11 and one of the guide rollers 15, that is, the guide roller 15A, and the pressing roller 16 of the conveying section 11 is brought into contact with the negative electrode sheet 103 from the opposite side of the guide roller 15A. The positive electrode sheet 101 is sandwiched and conveyed between the pressure roller 16 of the conveying section 12 and one guide roller 15, that is, the guide roller 15B, and the pressure roller 16 of the conveying section 12 is brought into contact with the positive electrode sheet 101 from the opposite side of the guide roller 15B. The belt-like bodies (corresponding one of the 51 and 52) are transported at a steady transport speed to the winding core 40 by the press rollers 16 at the transport sections (transport paths) 11 and 12, respectively. Among the press rolls 16, the press roll 16 disposed in the conveying section 11 is set as a press roll 16A, and the press roll 16 disposed in the conveying section 12 is set as a press roll 16B.

In the respective conveying sections 11 and 12, a detecting section (first detecting section) 17 is disposed upstream of the platen roller 16, and is disposed between the platen roller 16 and the corresponding one of the supplying sections (5 and 6). In the conveying sections 11 and 12, a detecting section (second detecting section) 18 is disposed downstream of the platen roller 16 and between the platen roller 16 and the winding core 40. In each of the conveying sections (conveying paths) 11, 12, the detecting section 17 detects at a position on the upstream side with respect to the platen roller 16: is formed in the abnormal shape portion of the corresponding one of the belt-shaped bodies (51, 52). In the respective conveying sections (conveying paths) 11 and 12, the detecting section 18 detects at a position downstream of the platen roller 16: is formed in the abnormal shape portion of the corresponding one of the belt-shaped bodies (51, 52). The detection units 17 and 18 detect abnormal shape portions using, for example, a CCD camera or a laser displacement meter. Examples of the abnormal shape portions formed in the negative electrode sheet 103 and the positive electrode sheet 101 include concave and convex portions, skew, and wrinkles. Among the detection units 17 and 18, the detection units 17 and 18 detected by the conveying unit 11 are set as detection units 17A and 18A, and the detection units 17 and 18 detected by the conveying unit 12 are set as detection units 17B and 18B.

The winding core 40 is mounted on a frame or the like, not shown. As shown in fig. 2, the winding core 40 is connected to a motor 50. The winding core 40 is driven to rotate by a motor 50. The winding core 40 has a first central axis C1 as a rotation center. The winding core 40 is rotated about the first center axis C1 with respect to the frame or the like by driving the motor 50.

The winding core 40 is configured to hold the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104, which are stacked, and to rotate around the first center axis C1, thereby winding the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 around the outer peripheral surface.

The winding core 40 is formed in a columnar shape extending along the first central axis C1. The winding core 40 is formed to have the same or substantially the same shape along the first central axis C1 at least at the portion around which the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 are wound. As shown in fig. 3, the winding core 40 has: two corner portions 41 formed at two positions that are symmetrical in the circumferential direction; and an outer peripheral surface 42 formed between the apex portions of the two corner portions 41. In other words, the winding core 40 is formed in a point-symmetrical shape about the first central axis C1 or in a symmetrical shape about the second central axis C2 connecting the two corners 41. Further, the winding core 40 preferably does not have a linear portion extending in a direction intersecting the first central axis C1 on an outer peripheral portion around which the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 are wound. In other words, the winding core 40 preferably has no straight line portion on the outer surface in the circumferential direction.

As shown in fig. 4, for example, the corner 41 forms a folding line (folding line) 100a in at least the innermost positive electrode sheet 101 or negative electrode sheet 103 of the wound body 100 around which the positive electrode sheet 101, separator 102, negative electrode sheet 103, and separator 104 are wound.

The angle θ of the tangent line to the corner 41 shown in fig. 3 is set to an angle at which the folding line 100a can be formed with little fluctuation in angular velocity. Specifically, the angle θ of the tangent line to the corner 41 is 120 ° or less. Preferably, the corner 41 is set at 90 °. By setting the angle θ of the tangent line to the corner 41 to 120 ° or less, the angle of the actual corner 41 becomes an acute angle at which the fold line 100a can be formed in the material. Therefore, the innermost peripheral portion of the wound body 100 wound by the winding core 40 having such corner portions 41 is formed with the fold line 100a as shown in fig. 4, and the portion of the wound body 100 where the fold line 100a is formed is substantially acute-angled.

The apex of the corner 41 is formed so as not to damage the positive electrode sheet 101 or the negative electrode sheet 103 in contact with it, and a fold line 100a can be formed. For example, the apex of the corner 41 may be formed in a curved surface shape having a radius of curvature r of 1mm or less. As an example, the apex of the corner 41 is formed in a curved surface shape having a radius of curvature r of 0.5 mm.

The outer peripheral surface 42 extends along the first central axis C1. The outer peripheral surface 42 is formed with, for example, one radius of curvature. The pair of outer peripheral surfaces 42 are formed such that the angle θ of the tangent to the corner 41 is 120 ° or less. Two ridge portions formed by a pair of outer peripheral surfaces 42 constitute a pair of corner portions 41.

As shown in fig. 3, the center of curvature C0 of the two outer peripheral surfaces 42 is located at a position offset from the second center axis C2 in a direction orthogonal or substantially orthogonal to the first center axis C1 and in a direction orthogonal to the second center axis C2 connecting the two corner portions 41, as schematically illustrated in the cross-sectional shape of the winding core 40. That is, as shown in fig. 5, the cross-sectional shape of the winding core 40 in a cross-section orthogonal or substantially orthogonal to the first central axis C1 is formed in such a shape that: when the centers C0 of the two virtual circles CI disposed at the predetermined radius are offset from each other, more specific examples are when the centers C0 of the two virtual circles CI at the predetermined radius are disposed at positions offset from the second center axis C2 in directions orthogonal to the first center axis C1 and the second center axis C2 connecting the two corners 41, respectively, and the cross-sectional shape of the winding core 40 is the same as or substantially the same as the intersecting shape of the two virtual circles CI.

In the example of the winding core 40 shown in fig. 5, the center C0 of one virtual circle CI is disposed on the outer periphery of the other virtual circle CI. That is, in the structure of the winding core 40 shown in fig. 5, the distance between the centers C0 of the two virtual circles CI is the same as the radius of the virtual circle CI.

Next, a specific example of the winding core 40 will be described. The winding core 40 has, for example, a pair (two) of chips 45. The winding core 40 holds the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and/or the separator 104 disposed in the slit 45a between the facing surfaces of the pair of chips 45. For example, the winding core 40 includes a holder 46 for holding the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 disposed in the slit 45 a.

By separating the surfaces of the pair of chips 45 facing each other, a slit 45a is formed between the pair of chips 45. A pair of chips 45 each have one corner 41. The pair of chips 45 are held in a predetermined arrangement relationship to form a pair of corners 41 and a pair of outer peripheral surfaces 42. The winding core 40 may have a moving mechanism and a driving source for varying the distance between the pair of chips 45. For example, the winding core 40 may have the following structure: when the wound roll 100 is removed from the winding core 40, the pair of chips 45 are moved so that the width of the slit 45a is reduced.

The surfaces of the pair of chips 45 facing each other are inclined surfaces inclined (intersecting) with respect to the second central axis C2, for example. Accordingly, the slit 45a is inclined with respect to the second center axis C2.

Kerf 45a is a gap or opening formed between the opposing surfaces of a pair of chips 45. The slit 45a extends along the first center axis C1. The slit 45a is formed in a shape capable of inserting the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and/or the separator 104. The width of the slit 45a in the circumferential direction of the winding core 40 is preferably as small as possible so that the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and/or the separator 104 can be inserted.

In such a winding core 40, the slit 45a is inclined with respect to the second central axis C2, so that the cross-sectional shape of the winding core 40 including the slit 45a is a point-symmetrical shape centered on the first central axis C1. Further, a part of the outer peripheral surface 42 of the winding core 40 is intermittently formed by the slit 45 a.

Further, by forming the slit 45a in a shape inclined with respect to the second central axis C2, an outer surface portion of the chip 45 forming the pair of outer peripheral surfaces 42 has a structure including: the first outer peripheral portion 45b and the second outer peripheral portion 45c have a longer circumferential length of the second outer peripheral portion 45c than the first outer peripheral portion 45 b. The first outer peripheral portion 45b of one chip 45 and the second outer peripheral portion 45c of the other chip 45 constitute one outer peripheral surface 42 having a slit 45 a. The second outer peripheral portion 45c of one chip 45 and the first outer peripheral portion 45b of the other chip 45 constitute the other outer peripheral surface 42 having the slit 45 a.

The clip 46 is, for example, a clip for holding the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and/or the separator 104 disposed in the slit 45 a. As shown by an arrow in fig. 3, the clamp 46 is opened and closed by power of, for example, a motor or the like. In fig. 3, the clamp 46 in the open state is shown by a solid line, and the clamp 46 in the closed state is shown by a broken line.

The motor 50 is, for example, a servo motor. The motor 50 controls the rotational speed using the control device 80.

The adjustment mechanism 60 includes: a roller 61, and a driving device 65. The roller 61 adjusts the insertion angle of the positive electrode sheet 101, separator 102, negative electrode sheet 103, and separator 104 supplied to the winding core 40 to the roller 61. That is, the roller 61 defines the insertion angles of the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 with respect to the winding core 40. The driving device 65 drives the roller 61. Specifically, the driving device 65 moves the roller 61 between the reference position and the winding position.

As an example, the driving device 65 includes a slider and a servomotor, and the roller 61 is moved in a predetermined direction by driving the slider and the servomotor. In another example, the driving device 65 includes an arm and a cylinder, one end of the arm is rotatably attached to a frame or the like, and the roller 61 is fixed to the other end of the arm. Further, a cylinder is connected to the arm. The cylinder expands and contracts in a predetermined direction to rotate the arm. Then, the arm rotates to move the roller 61 along an arc centered on the rotation axis of the arm.

The reference position is a position where the roller 61 is disposed when the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 are attached to the winding core 40. When the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 are attached to the winding core 40, for example, the separator 102, the negative electrode sheet 103, and the separator 104 are inserted between the outer peripheral surface of the winding core 40 and the positive electrode sheet 101 in a state where the end of the positive electrode sheet 101 is gripped by the winding core 40.

The winding position is a position where the roller 61 is disposed when the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 are wound around the winding core 40. When the positive electrode sheet 101 and the negative electrode sheet 103 are attached to the winding core 40, for example, the roller 61 moves to the winding position, and the insertion angles of the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 with respect to the insertion position of the winding core 40 are specified.

The cutting device 70 cuts the positive electrode sheet 101, separator 102, negative electrode sheet 103, and separator 104 supplied to the winding core 40. For example, the cutting device 70 includes: a cutter 71 for cutting, and a drive source 72 such as a motor for moving the cutter 71. The cutting device 70 moves the cutter 71 between the standby position and the cutting position by the driving source 72, and cuts the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 at the cutting position.

The control device 80 is a processing device such as a computer. The control device 80 includes: a storage medium such as a processor or an integrated Circuit (control Circuit) including a CPU (Central Processing Unit: central processing unit), an ASIC (Application SPECIFIC INTEGRATED Circuit), an FPGA (Field Programmable GATE ARRAY: field programmable gate array), and a memory. The control device 80 may be provided with only one integrated circuit or the like, or may be provided with a plurality of integrated circuits or the like. The control device 80 performs processing by executing a program or the like stored in a storage medium or the like. The control device 80 controls the operation of each element provided in the winding apparatus 1. The control device 80 controls driving of, for example, the four supply units 5 to 8, the four conveying units 11 to 14, the jigs 46, the motor 50, the driving device 65 of the adjustment mechanism 60, the cutting device 70, and the like. The control device 80 may further include: an input unit for inputting process conditions, operation conditions, and the like, and a display unit for displaying an operation state, an abnormal display, and the like.

The control device 80 performs rotation control, that is, makes the rotation speed of the motor 50 variable according to the distance from the rotation center of the winding core 40 to the outer surface contacted by the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104, so that the difference in the angular speed in one rotation (half rotation) of the winding core 40 is reduced.

Next, an example of a method for manufacturing an electrode group using the winding device 1 of the present embodiment will be described with reference to fig. 6.

First, the control device 80 performs an installation process. Specifically, the control device 80 controls the four supply units 5 to 8 and the four transport units 11 to 14, and inserts the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and/or the separator 104 into the slit 45a between the pair of chips 45 (step ST 1). Next, the control device 80 controls the jig 46 to hold the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and/or the separator 104 inserted into the slit 45a (step ST 2). When the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and/or the separator 104 are held by the winding core 40, the control device 80 controls the cutting means 70 to cut the portions of the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and/or the separator 104 inserted into the slit 45a as the distal end side (step ST 3). The mounting process is completed through these processes.

For example, the band-shaped material inserted into the slit 45a and held by the holder 46 may be any one of the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104, or may be all of the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104. For example, when any one of the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 is held by the slit 45a, the control device 80 may have the following steps: other band-like materials are interposed between the winding core 40 and the held band-like material.

Next, as a moving step, the control device 80 controls the driving of the driving device 65 to move the roller 61 from the reference position to the winding position. Next, as a winding step, the control device 80 controls the driving of the motor 50 to rotate the winding core 40, and winds the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 by a predetermined number of windings (step ST 4). For example, in the winding step, the winding core 40 rotates in a direction in which the material passes through the first outer peripheral portion 45b having a short length in the circumferential direction of the core 45 and reaches the corner portion 41 after the winding starts. In the winding process, the control device 80 controls the motor 50 to rotate the winding core 40 such that the difference in angular velocity generated by the spool angle in one rotation (half rotation) of the winding core 40 is reduced.

Thus, a wound body 100 is formed by winding the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104 at a predetermined number of cycles. When the roll 100 is formed, the control device 80 ends the winding process.

Next, the control device 80 controls the clamp 46 to release the holding of the manufactured wound body 100, controls the cutting means 70 to cut the positive electrode sheet 101, the separator 102, the negative electrode sheet 103, and the separator 104, and removes the wound body 100 from the winding core 40. As the mounting step of step ST1, the positive electrode sheet 101, separator 102, negative electrode sheet 103, and separator 104, which are manufactured later, are mounted on the winding core. In the mounting process of the positive electrode sheet 101, separator 102, negative electrode sheet 103, and separator 104 of the wound body 100 to be manufactured later, the positive electrode sheet 101, separator 102, negative electrode sheet 103, and separator 104 described in step ST3 may be cut, and the manufactured wound body 100 may be separated from the positive electrode sheet 101 and negative electrode sheet 103.

For example, as shown in fig. 4, the wound body 100 manufactured by the winding device 1 is punched from a direction orthogonal or substantially orthogonal to the second center axis C2 by a punching machine or the like (step ST 5). For example, the press is a flat plate press. As an example of the press conditions, the coil 100 is pressed by applying a load of 1t to the coil 100 at a temperature of 100 ℃ for several tens of seconds. Thereby, the wound body 100 is formed into a flat shape. According to an example of these steps, a wound body 100 such as an electrode group is manufactured.

Next, effects of the winding device 1 and the winding core 40 according to the present embodiment will be described.

The winding core 40 has: a pair of corners 41 having a tangent angle formed at a predetermined angle; and a pair of outer peripheral surfaces 42 having a predetermined radius of curvature between the pair of corners 41. The winding core 40 can form a folding line 100a with a pair of corners 41 at least at the innermost circumference. For example, the winding core 40 can form a folding line 100a at least on one of the positive electrode sheet 101 and the negative electrode sheet 103 by the pair of corners 41. The fold line 100a is formed by plastic deformation of the material of the innermost periphery at the time of punching. The fold line 100a is a crease when the wound body 100 is punched, and guides deformation of the positive electrode sheet 101 and the negative electrode sheet 103 (material) when the wound body 100 is punched.

Further, the fold line 100a can increase the friction coefficient of the portion where the innermost layer (material) of the fold line 100a and the layer (material) adjacent to the innermost layer overlap. For example, the fold line 100a can increase the friction coefficient at the overlapping portion of the positive electrode sheet 101 and the negative electrode sheet 103 adjacent to each other via the separators 102, 104. Thus, the end of the band-like material (positive electrode sheet 101 or negative electrode sheet 103) on the innermost peripheral side of the wound body 100 is fixed by the fold line 100 a. Since the innermost material (positive electrode sheet 101 or negative electrode sheet 103) is fixed to the wound body 100 manufactured by the winding core 40, the innermost material (positive electrode sheet 101 or negative electrode sheet 103) can be prevented from being displaced. That is, the winding core 40 can form a crease in the innermost part Zhou Bo of the wound body 100 by the corner 41 as an edge portion when winding the material, and the innermost part Zhou Bo is in a state of being less likely to deviate.

Therefore, the shape of the manufactured roll 100 is maintained in a shape in which the winding core 40 is pulled out from the roll 100. This makes it possible to suppress the occurrence of slack in the innermost positive electrode sheet 101 or negative electrode sheet 103 in the wound body 100. Further, since the shape of the wound body 100 is maintained, the innermost positive electrode sheet 101 or negative electrode sheet 103 can be pressed without being displaced during pressing, and occurrence of wrinkles, steps, and the like on the innermost positive electrode sheet 101 or negative electrode sheet 103 that is plastically deformed during pressing can be suppressed.

In the winding device 1, the winding core 40 is rotated in a direction in which the material passes through the first outer peripheral portion 45b having a short length in the circumferential direction of the core 45 and reaches the corner portion 41 after the winding is started, so that the folding line 100a can be formed on the end portion side of the material. Thereby, the winding device 1 and the winding core 40 can further prevent the end portion of the innermost circumference side of the material from being loosened. Therefore, the winding device 1 and the winding core 40 can produce the wound body 100 of excellent quality.

Further, since the pair of outer peripheral surfaces 42 between the pair of corners 41 of the winding core 40 are curved with one radius of curvature, there is no straight line portion, and the change in the distance from the rotation center of the winding core 40 to the outer surface in the circumferential direction can be made as small as possible.

That is, if a winding core whose circumferential shape (cross-sectional shape) of the outer peripheral surface is not circular is used, the distance between the point on the winding core that contacts the band-like material and the rotation center of the winding core varies during one rotation (half rotation). That is, the distance between the point on the winding core that contacts the strip material and the center of rotation of the winding core will vary depending on the angle of the winding shaft. Thus, when winding material, the angular velocity varies with the radius of the winding core. If the traveling speed of the material (the object to be wound) varies, the traveling of the object to be wound shifts and jumps, and therefore, it is difficult to wind the object to be wound neatly. In order to solve this problem, control is performed to suppress the fluctuation of the winding speed, and the rotation of the winding core is adjusted by the control device 80 or the like, so that the rotation speed of the winding core is reduced when the angular speed is increased, and the rotation of the winding core is increased when the angular speed is reduced. However, when the rotational speed of the winding core is controlled, if the angular speed is rapidly changed, the winding core needs to be rapidly accelerated/decelerated. When the winding core is rapidly accelerated/decelerated, the motor 50 is difficult to respond, and it is difficult to wind the material at high speed, and productivity of the wound body is lowered.

However, the winding core 40 according to the embodiment can reduce the change in the distance from the rotation center of the winding core 40 to the outer surface in the circumferential direction as small as possible, and thus can reduce the acceleration/deceleration per rotation (half rotation) of the winding core 40. That is, the winding core 40 is utilized to reduce the speed variation of the winding shaft. Therefore, the winding core 40 does not need rapid acceleration or rapid deceleration, and can wind the material at a high speed. Therefore, the winding core 40 and the winding device 1 can suppress a decrease in productivity.

Next, a description will be given of the winding core 40 according to this embodiment and the winding core according to the comparative example which is the conventional art. First, the winding cores 40A to 40D of comparative examples 1 to 4 will be described with reference to fig. 7 to 10.

Comparative example 1

As shown in fig. 7, the cross-sectional shape (circumferential shape) of the winding core 40A of comparative example 1 orthogonal to the first central axis C1 is formed in a circular shape.

Comparative example 2

As shown in fig. 8, the cross-sectional shape (circumferential shape) of the winding core 40B of comparative example 2 orthogonal to the first central axis C1 is formed in a flat hexagon.

Comparative example 3

As shown in fig. 9, the cross-sectional shape (circumferential shape) of the winding core 40C of comparative example 3 orthogonal to the first central axis C1 is formed in a diamond shape.

Comparative example 4

As shown in fig. 10, the cross-sectional shape (circumferential shape) of the winding core 40D of comparative example 4 orthogonal to the first central axis C1 is formed in an elliptical shape.

Next, the winding cores 40A to 40D of these comparative examples will be described in comparison with the winding core 40 of the embodiment.

Comparison of the embodiment with comparative example

First, the winding core 40A of comparative example 1 is compared with the winding core 40 of the embodiment. Fig. 11 shows an example of a wound body 100A manufactured using the winding core 40A of comparative example 1. Since the winding core 40A of comparative example 1 does not substantially need to change the winding speed when the winding core 40A rotates, the winding speed can be made high and productivity can be high. However, as shown in fig. 11, in the wound body 100A in which the material is wound by the winding core 40A, the end of the material on the innermost circumference is not fixed, and the material on the innermost circumference tends to be loosened. Relaxation occurs in cases such as: when the winding core 40A is pulled out from the winding body 100A, when the winding body 100A is moved after the pulling out, and when the winding body 100A is punched. The wound body 100A cannot be corrected after the material is relaxed.

Further, the wound body 100A, in which the material is relaxed, is different depending on the characteristics, but is a defective product. If the press is performed in a loose shape, the loose material cannot be properly set, and wrinkles such as zigzag are generated. Therefore, a step is formed in the creased portion generated during pressing, and the step portion may be a foreign matter to pierce other portions, resulting in failure of the characteristics of the wound body 100A (electrode group).

In this way, the wound body 100A, in which the material is relaxed, is liable to be a defective product. Further, since the deformation amount of the wound body 100A at the time of pressing is large, there is a possibility that the shape of the material on the innermost circumference side of the wound body 100A may be changed at the time of pressing even if no slack is generated. In addition, friction between adjacent materials of the roll 100A is also liable to occur at the time of pressing, thereby causing damage.

In contrast, according to the winding core 40 of the present embodiment, as shown in fig. 4, the fold line 100a can be formed by the material of at least the innermost circumference of the wound body 100 at the vertex of the pair of corners 41. Therefore, the winding core 40 according to the embodiment can suppress the occurrence of slack on the innermost circumference side of the wound body 100. Further, by forming the outer peripheral surface 42 of the winding core 40 into a curved surface having a predetermined radius of curvature, it is possible to suppress a change in speed when the winding core 40 rotates, and thus to make the rotation speed high. Therefore, the winding core 40 of the embodiment can ensure high productivity.

Next, the winding cores 40B and 40C of comparative examples 2 and 3 were compared with the winding core 40 of the embodiment. The winding cores 40B and 40C of comparative examples 2 and 3 can be formed with a folding line, which is a trace of plastic deformation in the innermost material after winding. Therefore, the winding body is less likely to be loosened, and the winding cores 40B and 40C of comparative examples 2 and 3 can be wound in a shape close to the shape after pressing, so that the deformation amount and the friction amount at the time of pressing can be reduced similarly to the winding core 40 of the embodiment. The winding cores 40B and 40C of comparative examples 2 and 3 can reduce damage to the wound body, and thus the quality of the produced wound body is excellent. However, the cross-sectional shapes (circumferential shapes) of the winding cores 40B and 40C of comparative examples 2 and 3 have a linear portion formed on the outer peripheral surface, and therefore, the angular velocity during winding varies greatly, making it difficult to wind the material at high speed.

The winding core 40 according to the embodiment and the winding core 40B of the comparative example 2 will be described with reference to specific examples of fig. 12 to 17. Fig. 12 and 13 show the state of each spool angle (rotation angle of the spool) when the spool 40 of the embodiment and the spool 40B of the comparative example 2 are rotated by half a turn. In fig. 12 and 13, the rotation direction R of the winding cores 40 and 40B is indicated by an arrow.

Fig. 14 and 15 are explanatory diagrams showing the relationship between the spool angle and the material speed (angular velocity) when the winding cores 40 according to the embodiment and the winding cores 40B according to the comparative example 2 are rotated at the same speed. Fig. 16 and 17 are explanatory diagrams showing the relationship between the spool angle and the spool speed (rotational speed) when the rotation of the winding core is controlled so that the material speed is constant in the winding core 40 according to the embodiment and the winding core 40B according to the comparative example 2, respectively. The winding core 40C of comparative example 3 has the same characteristics as the winding core 40B of comparative example 2, and therefore, a detailed description thereof is omitted.

As shown in fig. 13 and 15, when the winding core 40B of comparative example 2 is rotated, the material is wound around a part (linear portion) of the outer peripheral surface extending in a straight line in the circumferential direction, and the angular velocity greatly fluctuates. Therefore, as shown in fig. 17, when the rotation of the winding core 40B is controlled so that the angular velocity is constant, the magnitude of the acceleration and deceleration of the winding shaft velocity is large. Regarding the winding core 40B of comparative example 2, the motor 50 is required to perform rapid acceleration and rapid stop, but it is difficult for the performance of the motor 50 to achieve rapid acceleration and rapid stop, and thus it is difficult to control the motor 50. Therefore, the winding core 40B of comparative example 2 is difficult to wind the material at high speed.

In contrast, as shown in fig. 12 and 14, when the winding core 40 of the present embodiment is rotated, the variation in angular velocity is smaller in the circumferential direction due to the outer peripheral surface 42 having a predetermined radius of curvature than in comparative example 2. Therefore, as shown in fig. 16, when the rotation of the winding core 40 is controlled so that the angular velocity is constant, the magnitude of the acceleration and deceleration of the winding shaft velocity becomes smaller than that of comparative example 2. The winding core 40 according to the embodiment does not require the motor 50 to perform rapid acceleration or rapid stop, and thus can smoothly adjust the winding shaft speed. Therefore, the winding core 40 according to the embodiment is easy to control as compared with the winding core 40B of comparative example 2, and is capable of winding a material at a high speed as compared with the winding core 40B of comparative example 2. In the winding core 40 according to the embodiment, the folding line 100a can be formed by using the material of the pair of corners 41 at the innermost circumference, similarly to the winding core 40B of the comparative example 2.

Next, the winding core 40D of comparative example 4 was compared with the winding core 40 of the embodiment. The winding core 40D of comparative example 4 can reduce the variation in angular velocity similarly to the winding core 40 of the present embodiment, and thus can smoothly adjust the winding shaft velocity. Therefore, the winding core 40D of comparative example 4 has good motor responsiveness as in the winding core 40 of the present embodiment. But differs from the winding core 40 of the present embodiment in that: the winding core 40D of comparative example 4 cannot form a fold line in the material of the innermost circumference of the wound body. Therefore, in the wound body manufactured using the winding core 40D of comparative example 4, since the innermost end is not fixed, the material is liable to be loosened in the same manner as in comparative example 1.

Evaluation test of embodiment mode and comparative example

Next, the evaluation test of the winding core 40 according to the embodiment and the winding core 40A of the comparative example 1 will be described below. As an evaluation test, a wound body wound with the winding core 40 of the embodiment and the winding core 40A of the comparative example 1 was punched, and the material of the innermost circumference of the punched wound body was visually confirmed to determine whether wrinkles were generated.

Fig. 18 shows the evaluation test results. Fig. 19 shows an example of the material of the innermost circumference of the punched wound body 100 manufactured by the winding core 40 according to the embodiment, and fig. 20 shows an example of the material of the innermost circumference of the punched wound body 100A manufactured by the winding core 40A of the comparative example 1.

As shown in fig. 18, with respect to the winding core 40 of the embodiment, 247 wound bodies 100 were produced, and as shown in fig. 19, no wrinkles were generated at the bending positions of the innermost circumference of the wound bodies 100 after pressing. This is considered to be because the material of the innermost periphery of the wound body 100 before the pressing forms the folding line 100a, and therefore, the material of the innermost periphery is not deflected or displaced.

In contrast, as shown in fig. 18, when 29 wound bodies 100A were produced with respect to the winding core 40A of comparative example 1, wrinkles were generated at the bending positions of the material at the innermost periphery of the wound bodies 100A after pressing as shown by the arrows in fig. 20. 24% of the wound bodies manufactured using the winding core 40A of comparative example 1 were creased. This is considered to be because the winding core 40A of comparative example 1, which cannot form the folding line 100A, does not form the folding line in the wound body 100A.

From the results of such evaluation tests, it was found that: the winding core 40 according to the embodiment can suppress the occurrence of wrinkles in the material by forming the fold line 100a in the wound body 100. Therefore, the winding core 40 according to the embodiment can maintain high productivity of the wound body 100 and improve quality.

Next, an example of a nonaqueous electrolyte battery 2 using the wound body 100 as the electrode group 155 will be described with reference to fig. 21. Fig. 21 is an exploded perspective view of an example of a nonaqueous electrolyte battery according to an embodiment.

The secondary battery shown in fig. 21 is a sealed square nonaqueous electrolyte battery 2. The nonaqueous electrolyte battery 2 shown in fig. 21 includes: the package case 151, the cap 152, the positive electrode external terminal 153, the negative electrode external terminal 154, and the electrode group 155. The package member is constituted by a package case 151 and a cover 152. The package 151 has a rectangular cylindrical shape with a bottom. The package case 151 is formed of a metal such as aluminum, aluminum alloy, iron, or stainless steel.

The flat electrode group 155 is formed in such a manner that: separator 158 is interposed between positive electrode 156 and negative electrode 157 and wound with winding core 40, and then punched flat. The positive electrode 156 is formed from the positive electrode sheet 101. The positive electrode 156 includes: for example, the positive electrode current collector 156a is a strip-shaped positive electrode current collector made of a metal foil, the positive electrode current collector sheet 156b is made of one end portion parallel to the long side of the positive electrode current collector, and the positive electrode material layer (positive electrode active material-containing layer) 156c is formed on the positive electrode current collector except at least a portion of the positive electrode current collector sheet 156 b.

The negative electrode 157 is formed from the negative electrode sheet 103. The negative electrode 157 includes: for example, the negative electrode collector 157a is a strip-shaped negative electrode collector made of a metal foil, the negative electrode collector tab 157b is made of one end portion parallel to the long side of the negative electrode collector, and the negative electrode material layer (negative electrode active material-containing layer) 157c is formed on the negative electrode collector except at least a portion of the negative electrode collector tab 157 b. In fig. 22, dots are shown in the regions showing the active material containing layers 156c and 157c for the purpose of explanation of the structure. The spacer layer 158 is formed by the spacers 102, 104.

Such positive electrode 156, separator 158, and negative electrode 157 are wound in such a way that: the positions of the positive electrode 156 and the negative electrode 157 are shifted so that the positive electrode collector 156b protrudes from the separator 158 in the winding axis direction of the electrode group and the negative electrode collector 157b protrudes from the separator 158 in the opposite direction. As shown in fig. 3, the electrode group 155 is wound in such a manner that the positive electrode collector tab 156b wound in a spiral shape protrudes from one end face and the negative electrode collector tab 157b wound in a spiral shape protrudes from the other end face. A nonaqueous electrolyte (not shown) is impregnated into the electrode group 155.

As shown in fig. 21, the positive electrode collector tab 156b and the negative electrode collector tab 157b are each divided into two bundles with the vicinity of the winding center of the electrode group as a boundary. The conductive clamp member 159 includes: the first and second clamping portions 159a and 159b having a substantially U-shape, and a connecting portion 159c electrically connecting the first clamping portion 159a and the second clamping portion 159 b. One bundle of the positive and negative electrode collector sheets 156b, 157b is sandwiched by the first sandwiching portion 159a, and the other bundle is sandwiched by the second sandwiching portion 159 b.

The positive electrode conductor 160 has: a support plate 160a having a substantially rectangular shape, a through hole 160b opening in the support plate 160a, and elongated collector portions 160c and 160d branched from the support plate 160a in two directions and extending downward. On the other hand, the negative electrode conductor 161 has: a support plate 161a having a substantially rectangular shape, a through hole 161b opening in the support plate 161a, and elongated collector portions 161c and 161d branched from the support plate 161a in two directions and extending downward.

The positive electrode conductor 160 sandwiches the sandwiching member 159 between the current collectors 160c, 160 d. The current collector 160c is disposed at the first clamping portion 159a of the clamping member 159. The current collector 160d is disposed in the second nip 159b. The current collecting portions 160c and 160d, the first and second sandwiching portions 159a and 159b, and the positive electrode current collecting tab 156b are joined by, for example, ultrasonic welding. Thus, the positive electrode 156 of the electrode group 155 and the positive electrode conductor 160 are electrically connected via the positive electrode collector tab 156 b.

The negative electrode conductor 161 sandwiches the sandwiching member 159 between the current collecting portions 161c and 161 d. The current collector 160c is disposed at the first clamping portion 159a of the clamping member 159. On the other hand, the current collecting portion 161d is disposed in the second sandwiching portion 159b. The current collecting portions 161c and 161d, the first and second sandwiching portions 159a and 159b, and the negative electrode current collecting tab 157b are joined by, for example, ultrasonic welding. Thereby, the negative electrode 157 of the electrode group 155 and the negative electrode conductor 161 are electrically connected via the negative electrode collector tab 157 b.

The materials of the positive and negative electrode conductors 160 and 161 and the sandwiching member 159 are not particularly specified, but the same materials as those of the positive and negative electrode external terminals 153 and 154 are preferable. The positive electrode external terminal 153 is made of aluminum or an aluminum alloy, and the negative electrode external terminal 154 is made of aluminum, an aluminum alloy, copper, nickel-iron plated, or the like. For example, when the material of the external terminal is aluminum or an aluminum alloy, the material of the conductor is preferably aluminum or an aluminum alloy. When the external terminal is copper, the conductor is preferably made of copper or the like.

The rectangular plate-like cover 152 is seam-welded to the opening of the package 151 by, for example, a laser. The cover 152 is formed of a metal such as aluminum, aluminum alloy, iron, or stainless steel. Preferably, the cover 152 and the package 151 are formed of the same metal. The positive electrode external terminal 153 is electrically connected to the support plate 160a of the positive electrode conductor 160, and the negative electrode external terminal 154 is electrically connected to the support plate 161a of the negative electrode conductor 161. The insulating gaskets 162 are disposed between the positive and negative external terminals 153 and 154 and the cover 152, and electrically insulate the positive and negative external terminals 153 and 154 from the cover 152. Preferably, the insulating gasket 162 is a resin molded product.

Next, fig. 22 shows an example of a method for manufacturing the nonaqueous electrolyte battery 2. First, slurry preparation, coating, slitting, rolling, and the like are performed, and the positive electrode 156 (positive electrode sheet 101) and the negative electrode 157 (negative electrode sheet 103) each having a porous layer formed on the surface by electrospinning as needed are transported to the winding core 40 of the winding device 1 (steps 201 and 202). Next, the positive electrode sheet 101 and the negative electrode sheet 103 are wound with the winding core 40 in a state where at least the separator 158 (separators 102, 104) as an insulating layer is interposed between the positive electrode sheet 101 and the negative electrode sheet 103 to produce a wound body 100 (steps ST1 to ST4, step 203), and the wound body 100 is subjected to flat press by a press machine or the like (steps ST5, step 204). The electrode group 155 is manufactured through these steps. Next, the electrode group 155 is stored in a packaging container, and the electrode group 155 is dried (step 205), and then an electrolyte is injected into the packaging container (step 206). Next, after the sealing of the package container, aging treatment or the like is performed, and then a degassing step is performed (step 207). Thereafter, the nonaqueous electrolyte battery 2 is charged and discharged (step 208), and the nonaqueous electrolyte battery 2 is inspected before shipment (step 209), whereby the nonaqueous electrolyte battery 2 is shipped (step 210). In this way, the electrode group 155 is manufactured using the winding core 40 described above, and the nonaqueous electrolyte battery 2 of high quality can be provided with high productivity.

According to the winding core 40 and the winding device 1 of the above embodiments, since the pair of corners 41 and the pair of outer peripheral surfaces 42 are provided, it is possible to suppress the relaxation of the innermost band-shaped material (the positive electrode sheet 101 or the negative electrode sheet 103) and reduce the acceleration and deceleration per one rotation (half-rotation) at the time of rotation.

The above-described embodiments are exemplified, and the structure thereof is not limited. For example, although the example in which the pair of outer peripheral surfaces 42 of the winding core 40 are formed of one radius of curvature is described by way of example above, it is not limited thereto. For example, as in the winding core 40 of another embodiment shown in fig. 23, each of the pair of outer peripheral surfaces 42 may have a curved surface shape formed by a plurality of different radii of curvature. For example, in the example schematically shown in fig. 23, the outer peripheral surface 42 of the winding core 40 is formed in an elliptical shape, and a pair of corners 41 are formed at both ends in the longitudinal direction. Such a winding core 40 can also suppress the relaxation of the innermost materials 101 and 103 and reduce the acceleration and deceleration per one rotation (half rotation) during rotation.

As described above, the winding device 1 and the winding core 40 can manufacture the winding body 100 for various purposes as long as the winding body 100 is formed by punching out a material capable of forming the folding line 100 a.

That is, in the above-described embodiment, the structure of the wound body 100 of the electrode group 155 used for manufacturing the secondary battery 2 using the winding core 40 and the winding device 1 is described as an example, but is not limited thereto. That is, the winding device 1 may be used to manufacture a wound body other than the electrode group 155 of the secondary battery 2 as long as the wound body is manufactured in a state where a plurality of belt-shaped bodies are stacked. For example, the wound body 100 manufactured using the winding device 1 may be used for a capacitor or a lithium ion capacitor. In addition, the roll 100 may be used for other applications.

That is, the roll 100 may be used for other applications than the above, as long as it is manufactured by winding a strip-like material locally subjected to plastic deformation around the winding core 40. In addition, the number of the band-like materials used for manufacturing the roll body can be appropriately set. For example, the band-shaped material is preferably two or more sheets, but may be one sheet.

The arrangement relation of the positive electrode sheet 101, separator 102, negative electrode sheet 103, and separator 104, which are transported and wound in the winding device 1, can be appropriately set. The material (layer) of the wound body 100 forming the innermost circumference of the fold line 100a may be a separator or may be a collector foil (positive electrode sheet 101 and negative electrode sheet 103).

According to the winding core and the winding device of at least one embodiment described above, by having a pair of corners and a pair of outer peripheral surfaces, it is possible to suppress the relaxation of the material at the innermost periphery and reduce the acceleration and deceleration at the time of rotation.

Although several embodiments of the present invention have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other modes, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. The embodiments and modifications thereof are also included in the invention described in the patent claims and the equivalent scope thereof, as long as they are included in the scope and gist of the invention.

Claims

1. A winding core, comprising: a pair of outer peripheral surfaces extending along a first central axis as a rotation center and formed with a predetermined radius of curvature, and a pair of corners extending along the first central axis at circumferentially symmetrical positions, the outer peripheral surfaces being wound with a band-like material.

2. The winding core according to claim 1, wherein,

The tangent angle of the corner is 120 DEG or less.

3. A winding core according to claim 1 or 2, characterized in that,

The outer peripheral surface is formed by a radius of curvature,

The center of curvature of the outer peripheral surface is located at a position offset from the second center axis in a direction orthogonal to the first center axis and a second center axis connecting the pair of corners.

4. A roll core according to claim 3, characterized in that,

Having a pair of chips extending along the first central axis and each having the corner,

The pair of chips have slits inclined with respect to the second central axis,

The material disposed in the slit is held.

5. A winding device is provided with:

the winding core of any one of claims 1 to 4; and

And a conveying section for conveying the material to the winding core.