Method for manufacturing electrode structure and manufacturing apparatus

Abstract

Embodiments of the present application relate to a manufacturing method and a manufacturing apparatus of an electrode structure. A manufacturing method and a manufacturing apparatus of an electrode structure capable of appropriately correcting a strip body bend due to rolling of an active material-containing layer even if the size of an uncoated region in the width direction of a current collector is large are provided. In the manufacturing method of the electrode structure, in a strip body in which an uncoated region in which the active material-containing layer is not formed is formed in one of a pair of long sides of the current collector and in the vicinity thereof, the active material-containing layer is rolled, and between a rolling section in which the active material-containing layer is rolled and a pulling section in which the strip body is pulled, a tension in the length direction is applied to the strip body. In the manufacturing method, the uncoated region is elongated in the length direction by pressing the uncoated region of the current collector with a protrusion that protrudes to the outer circumferential side between the rolling section and the pulling section. The protrusion length of the protrusion up to the tip end is larger than the thickness of the active material-containing layer after rolling.

Description

Technical Field

[0001] The embodiments of the present invention relate to a method and apparatus for manufacturing an electrode structure. Background Technology

[0002] In batteries such as secondary batteries, electrodes such as positive and negative electrodes are formed by electrode structures. Each electrode structure includes a current collector and an active material layer coated on the surface of the current collector. The current collector has a pair of long sides along its length. In the current collector of the electrode structure, an uncoated area is formed on one of the long sides and its vicinity, where neither of the two main surfaces is coated with the active material layer. In the manufacture of such an electrode structure, with the uncoated area on one of the long sides and its vicinity formed in the current collector, an active material layer is coated on the surface of the current collector. Furthermore, after drying the active material layer coated on the current collector, the active material layer is rolled using a rolling mill or similar device while the strip containing the active material layer is being transported.

[0003] In the manufacture of the electrode structure, by rolling an active material layer as described above, the current collector is elongated along its length in the coated area on at least one of a pair of main surfaces of the current collector due to the pressure generated by rolling. On the other hand, in the uncoated area of ​​the current collector, no rolling pressure is applied, so the current collector does not elongate along its length. Therefore, due to the rolling of the active material layer, the conveyed strip (current collector) is bent in a state where the side containing the uncoated area is bent on the inside.

[0004] In the manufacture of the electrode structure, the bending of the strip caused by rolling of the active material layer is corrected. In correcting the bending of the strip, the strip is pulled downstream of the rolling section containing the active material layer, thereby applying tension in the length direction between the pulling section and the rolling section. Furthermore, a protrusion is provided on the outer circumferential surface of the guide rollers that guide the strip between the rolling section and the pulling section. This protrusion presses against the uncoated area of ​​the current collector in the tensioned strip, causing the uncoated area to elongate along the length direction, thus correcting the bending.

[0005] In batteries using electrodes formed from electrode structures, the width of the uncoated area in the width direction needs to be relatively large within the strip. During the manufacturing of the electrode structure, it is necessary to appropriately correct the bending of the strip caused by rolling the active material layer, even if the size (width) of the uncoated area in the width direction of the current collector increases. Summary of the Invention

[0006] The problem to be solved by the present invention is to provide a method and apparatus for manufacturing an electrode structure that can appropriately correct the bending of the strip caused by rolling of the active material layer, even if the size of the uncoated area in the width direction of the current collector becomes larger.

[0007] According to the method for manufacturing an electrode structure according to the embodiment, a strip is conveyed, in which an active material layer is coated on the surface of a current collector, and an uncoated area without the active material layer is formed in the current collector on one of a pair of long sides along the length direction and in its vicinity. In the manufacturing method, the active material layer is rolled in the conveyed strip. Downstream of the rolling section where the active material layer is rolled, the strip is pulled downstream, thereby applying tension in the length direction to the strip between the pulling section and the rolling section. In the manufacturing method, the uncoated area of ​​the current collector is pressed against the tensioned strip using a protrusion protruding outward from the outer periphery of a roller between the rolling section and the pulling section, thereby elongating the uncoated area along the length direction. The protrusion, extending from its protruding end, is longer than the thickness of the active material layer after rolling by the rolling section.

[0008] Based on the above configuration, a method and apparatus for manufacturing an electrode structure can be provided that can appropriately correct the bending of the strip caused by rolling of the active material layer, even if the size of the uncoated area in the width direction of the current collector becomes larger. Attached Figure Description

[0009] Figure 1 This is a schematic diagram showing an example of an electrode structure formed in the embodiment, viewed from one side in the thickness direction.

[0010] Figure 2 It is roughly represented by a cross section or approximately orthogonal to the length direction. Figure 1 A cross-sectional view of the electrode structure.

[0011] Figure 3 This is a schematic diagram illustrating an example of a manufacturing apparatus for producing an electrode structure in an embodiment.

[0012] Figure 4 This is a schematic diagram illustrating an example of a measurement method for measuring the amount of bending of a strip that has bent due to processes such as rolling with an active material layer.

[0013] Figure 5 This is a cross-sectional view of an example of the structure of the elongated portion, shown in the manufacturing apparatus of the embodiment, with a section parallel or substantially parallel to the axial direction of the guide roller.

[0014] Figure 6 Is Figure 5A cross-sectional view of the elongated portion of the guide roller, roughly showing the protrusions of the guide roller and the surrounding structure, with a section parallel or approximately parallel to the axial direction of the guide roller.

[0015] Figure 7 This is a cross-sectional view of the protrusion of the guide roller and its surrounding structure, roughly showing a section parallel or approximately parallel to the axial direction of the guide roller in the elongated section of a certain modified manufacturing apparatus.

[0016] Figure 8 In the context of Figure 7 In the elongated section of the manufacturing apparatus of a certain modified example, a cross-sectional view is shown, roughly representing the protrusion of the guide roller and the surrounding structure, with a section parallel or approximately parallel to the axial direction of the guide roller.

[0017] Figure 9 This is a schematic diagram showing the measurement results of the conditions and bending amount of each of Examples 1 to 8 and Comparative Example 1 in verification related to the implementation method, etc.

[0018] (Explanation of reference numerals in the attached diagram)

[0019] 1…Electrode structure, 1A…Strip, 2…Current collector, 3…Layer containing active material, 5, 6…Main surface, 7…Long side (first long side), 8…Long side (second long side), 10…Coating end, 11…Coated area, 12…Uncoated area, 15…Manufacturing device, 16…Conveying section, 21…Rolling section, 22…Pulling section, 23…Elongation section, 25…Winding section, 27A~27C…Guide rollers, 40…Protrusion, 41…Protruding end face, 43…Protrusion amount variation section, M1~M4…Stepped section, H…Protruding length, h…Step difference, w0…Specified width dimension, w…Width dimension, b…Dimension, η…Bending amount. Detailed Implementation

[0020] Hereinafter, the embodiments will be described with reference to the accompanying drawings.

[0021] In this embodiment, a method and apparatus for manufacturing an electrode structure are provided. The electrode structure manufactured in this embodiment is used in batteries such as secondary batteries to form a positive or negative electrode. Figure 1 as well as Figure 2 This illustrates an example of an electrode structure 1 formed in an embodiment, etc. For example... Figure 1 as well as Figure 2 As shown, in electrode structure 1, the length direction (direction indicated by arrow L1), the width direction (direction indicated by arrow W1) which intersects (orthogonally or approximately orthogonally) the length direction, and the thickness direction (direction indicated by arrow T1) which intersects (orthogonally or approximately orthogonally) the length direction and the width direction. Figure 1 The view is shown from one side in the thickness direction. Figure 2 The cross-section is shown as orthogonal or approximately orthogonal to the length direction. In electrode structure 1, the dimensions in the length direction are larger than the dimensions in the width direction and the dimensions in the thickness direction, respectively, and the dimensions in the width direction are larger than the dimensions in the thickness direction.

[0022] In one example, the electrode structure 1 serves as the positive or negative electrode of a battery such as a lithium-ion secondary battery. In another example, the electrode structure 1 is divided into multiple electrode sheets along its length. Furthermore, each of the multiple electrode sheets serves as either the positive or negative electrode of the battery. The electrode structure 1 includes a current collector 2 and an active material layer 3 coated on the surface of the current collector 2. The current collector 2 is formed of a conductive metal and has a pair of main surfaces 5 and 6, and a pair of long sides 7 and 8. The main surfaces 5 and 6, and the long sides 7 and 8, extend along the length direction from one end of the electrode structure 1 to the other. Additionally, the main surfaces 5 and 6 extend from the long side 7 to the long side 8 along the width direction of the electrode structure 1. The main surface 5 faces one side in the thickness direction of the electrode structure 1, and the main surface 6 faces the opposite side in the thickness direction of the electrode structure 1.

[0023] The long side (first long side) 7 forms one edge of the current collector 2 in the width direction of the electrode structure 1. The long side (second long side) 8 forms an edge opposite to the long side 7 of the current collector 2 in the width direction of the electrode structure 1. Furthermore, the active material layer 3 extends from one end of the electrode structure 1 to the other in the length direction. Moreover, the active material layer 3 extends from the long side 8 of the current collector 2 to the coating end 10 in the width direction of the electrode structure 1. Viewed in the thickness direction, the end of the electrode structure 1 opposite to the coating end 10 in the width direction overlaps with the long side 8 of the current collector 2. The coating end 10 is located on the side where the long side 7 is located relative to the center position of the electrode structure 1 in the width direction. Therefore, the dimension between the long side 8 and the coating end 10 in the width direction of the electrode structure 1 is larger than the dimension between the long side 7 and the coating end 10 in the width direction of the electrode structure 1.

[0024] exist Figure 1 as well as Figure 2In one example, a coating region 11, containing the active material layer 3, is formed on both the long side 8 and the coating end 10 of the current collector 2, on both of its main surfaces 5 and 6. Furthermore, an uncoated region 12, where neither of the main surfaces 5 and 6 of the current collector 2 is coated or supports the active material layer 3, is formed on the long side 7 and the coating end 10 of the electrode structure 1. Therefore, in the current collector 2, an uncoated region 12, where neither of the main surfaces 5 and 6 is coated with the active material layer 3, is formed on or near the long side 7. In the electrode structure 1, the uncoated region 12 protrudes from the coating end 10 containing the active material layer 3 towards the side opposite to the side containing the long side 8 in the width direction. Alternatively, in another example, the active material layer 3 may be supported only on one of the main surfaces 5 and 6 of the current collector 2 within the coating region 11. Therefore, in the coating area 11, it is sufficient to coat and support the active material layer 3 on at least one of the pair of main surfaces 5 and 6 of the current collector 2.

[0025] When electrode structure 1 is used to form the positive electrode, the current collector 2 is not limited to this, and can be formed of any one of aluminum, aluminum alloy, stainless steel, and titanium, with a thickness of about 10 μm to 30 μm. The active material layer 3 may also contain a positive electrode active material, and may contain a binder and a conductive agent. The positive electrode active material is not limited to this, and examples include oxides, sulfides, and polymers that can intercalate and deintercalate lithium ions. The positive electrode active material may contain at least one selected from the group consisting of lithium manganese composite oxide, lithium nickel composite oxide, lithium cobalt aluminum composite oxide, lithium nickel cobalt manganese composite oxide, spinel lithium manganese nickel composite oxide, lithium manganese cobalt composite oxide, lithium iron oxide, lithium fluoride ferric sulfate, lithium iron composite phosphate compound, and lithium manganese composite phosphate compound.

[0026] As a conductive agent, one or more carbonaceous materials may be used. Examples of carbonaceous materials that serve as conductive agents include acetylene black, Ketjen black, graphite, and coke. Additionally, a polymer resin may be used as the binder. The binder may contain at least one material selected from the group consisting of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluororubber, ethylene-butadiene rubber, polypropylene (PP), polyethylene (PE), carboxymethyl cellulose (CMC), polyimide (PI), and polyacrylamide (PAI).

[0027] When electrode structure 1 is used to form the negative electrode, the current collector 2 is not limited to this, and can be formed from any of zinc, aluminum, aluminum alloys, and copper, with a thickness of approximately 10 μm to 30 μm. The negative electrode active material layer contains a negative electrode active material, and may also contain a binder and a conductive agent. The negative electrode active material is not particularly limited, and examples include metal oxides, metal sulfides, metal nitrides, and carbonaceous materials capable of intercalating and deintercalating lithium ions. As a metal oxide that serves as the negative electrode active material, titanium oxide can be listed. Moreover, titanium oxides that serve as negative electrode active materials may include, for example, titanium oxide, lithium titanium oxide, niobium titanium oxide, and sodium niobium titanium oxide. As conductive agents and binders, the same materials as those used in the formation of the positive electrode can be listed.

[0028] In the manufacture of electrode structure 1, a slurry is prepared by suspending an active material (which will become the positive or negative electrode active material), a conductive agent, and a binder in an organic solvent. At this time, regarding the proportions of the active material, conductive agent, and binder, the active material is preferably 70% by mass or more and 95% by mass or less, the conductive agent is preferably 3% by mass or more and 20% by mass or less, and the binder is preferably 2% by mass or more and 10% by mass or less. Furthermore, the prepared slurry is applied to the surface of current collector 2, and a strip containing an active material layer 3 is coated on the surface of current collector 2. The slurry application is performed, for example, using a coating head.

[0029] In the manufacture of electrode structure 1, electrode structure 1 is formed by performing the processes described later on a strip as described above. In the strip, the length direction, width direction, and thickness direction are defined similarly to electrode structure 1, and coated areas 11 and uncoated areas 12 are formed. Therefore, in the strip, in the current collector 2, an uncoated area 12 is formed on and near the long side 7, where the active material layer 3 is not coated on either of the pair of main surfaces 5 and 6. Furthermore, in the strip, in the width direction from the long side 8 of the current collector 2 to the coated end 10 containing the active material layer 3, a coated area 11 is formed where at least one of the pair of main surfaces 5 and 6 of the current collector 2 is coated with the active material layer 3. In the manufacture of electrode structure 1, after the active material layer 3 is coated onto the current collector 2, the active material layer 3 (slurry) coated on the surface of the current collector 2 is dried.

[0030] Furthermore, in a battery using an electrode formed from the electrode structure 1, the size (width) b of the uncoated area 12 in the width direction needs to be relatively large within the strip. In one example, when the size b of the uncoated area 12 in the width direction of the strip (current collector 2) is greater than 25 mm, an active material layer 3 is coated on the current collector 2. In this case, the size b of the uncoated area 12 in the width direction in the manufactured electrode structure 1 is larger than 25 mm. However, even when the size b of the uncoated area 12 in the width direction of the strip is greater than 25 mm, the size of the coated area 11 in the width direction is larger than the size b of the uncoated area 12 in the width direction.

[0031] Figure 3 This illustrates an example of a manufacturing apparatus 15 for manufacturing electrode structure 1. Figure 3 The diagram shows the process of drying the active material layer 3 applied to the current collector 2 during the manufacture of the electrode structure 1. Figure 3 One example of the manufacturing apparatus 15 includes a conveying unit 16. In the conveying unit 16, a strip 1A, after an active material layer 3 has been coated on a current collector 2 and the coated active material layer 3 has been dried, is conveyed. In the conveying unit 16, a conveying direction (indicated by arrow F1) and a width direction that intersects (orthogonally or substantially orthogonally) the conveying direction are defined. Figure 3 In the conveying section 16, the direction orthogonal or approximately orthogonal to the paper surface is the width direction. Furthermore, in the conveying section 16, the side conveying the strip 1A is designated as the downstream side, and the side opposite to the conveying strip 1A is designated as the upstream side. In the conveying section 16, the strip 1A is conveyed with its length direction along the conveying direction and its width direction along the width direction of the conveying section 16. Therefore, in the conveying section 16, the thickness direction of the strip 1A intersects (or is orthogonal or approximately orthogonal to) both the conveying direction and the width direction of the conveying section 16.

[0032] Figure 3 One example of the manufacturing apparatus 15 includes a rolling section 21, a drawing section 22, an elongation section 23, and a winding section 25. In the manufacturing apparatus 15, a strip 1A containing an active material layer 3, after drying, is fed into the rolling section 21. Then, the strip 1A passes through the elongation section 23 and the drawing section 22 in sequence from the rolling section 21 and is conveyed to the winding section 25. By performing the processes based on the rolling section 21, the elongation section 23, and the drawing section 22 (described later) on the conveyed strip 1A, an electrode structure 1 is formed. The winding section 25 winds the conveyed strip 1A, i.e., the formed electrode structure 1. Figure 3In one example, the winding section 25 includes a winding spool 26, and the electrode structure 1 (strip 1A) is wound in a cylindrical shape around the winding spool 26. Additionally, in Figure 3 In one example, the strip 1A is guided from the upstream side to the downstream side by three guide rollers (rollers) 27A, 27B, and 27C between the rolling section 21 and the pulling section 22 of the conveying section 16. Additionally, the strip 1A is guided from the upstream side to the downstream side by guide roller 28 between the pulling section 22 and the winding section 25. The guide rollers 27A to 27C and 28 are, for example, made of a metal such as stainless steel.

[0033] The rolling section 21 rolls the active material layer 3 in the conveyed strip 1A using a roller press or the like. The rolling section 21 includes a pair of pressure rollers 31 and 32, which are made of metals such as stainless steel. The pressure roller 31 presses the active material layer 3 from one side of the strip 1A in the thickness direction, while the pressure roller 32 presses the active material layer 3 from the opposite side of the strip 1A in the thickness direction. Thus, the active material layer 3 is sandwiched between the pressure rollers 31 and 32 in the thickness direction of the strip 1A, and pressure (pressing) from the strip 1A in the thickness direction is applied to the active material layer 3. At this time, with the active material layer 3 coated on both sides of the current collector 2, the active material layer 3 is pressed while the pressure rollers 31 and 32 are in contact with it. Furthermore, when the active material layer 3 is only coated on one side of the current collector 2, the active material layer 3 is pressed while one of the pressure rollers 31 and 32 is in contact with the active material layer 3 and the other of the pressure rollers 31 and 32 is in contact with the coating area 11 of the current collector 2. Due to the pressure from the pressure rollers 31 and 32, the active material layer 3 is compressed in the thickness direction of the strip 1A and stretched in the length direction of the strip 1A.

[0034] Furthermore, the rolling pressure applied to the active material layer 3 is also applied to at least one of the pair of main surfaces 5 and 6 of the current collector 2 in the coating area 11 where the active material layer 3 is applied. Therefore, in the coating area 11, the current collector 2 is elongated along its length due to the rolling pressure of the active material layer 3. On the other hand, the pressure rollers 31 and 32 do not apply the pressure generated by the rolling of the active material layer 3 to the uncoated area 12 of the current collector 2. Therefore, in the rolling of the active material layer 3, the uncoated area 12 of the current collector 2 is not elongated along its length. As described above, since the current collector 2 is elongated along its length only in the coating area 11, the conveyed strip 1A (current collector 2) is bent in a bent-in state on the side where the uncoated area 12 is located due to the rolling of the active material layer 3.

[0035] Here, the amount of bending of the strip 1A in the bent state as described above can be measured. Figure 4 This illustrates an example of a measurement method for measuring the amount of bending of a bent strip 1A. Figure 4 In one example, as described above, due to the rolling process containing the active material layer 3, the conveyed strip 1A (current collector 2) bends in a state where the uncoated area 12 is located, becoming the inner side of the bend. Figure 4 In one example of the measurement method, two points P1 and P2 are determined on the long side 8 of the current collector 2, that is, at one end opposite to the coating end 10 containing the active material layer 3 in the width direction of the strip 1A, with a straight-line distance D between them. Furthermore, a reference straight line α connecting points P1 and P2 is defined, and the amount of protrusion (protrusion dimension) extending from the reference straight line α towards the curved outer side 8 (the end opposite to the coating end 10 containing the active material layer 3) is calculated as the bending amount η. That is, the distance of the protruding end of the protruding portion of the long side 8 relative to the reference straight line α is calculated as the bending amount η. A larger bending amount η indicates a greater curvature of the strip 1A.

[0036] In this embodiment, the bending of the strip 1A (current collector 2) caused by rolling of the active material layer 3 is corrected by the pulling part 22 and the elongating part 23. The pulling part 22 is disposed downstream of the conveying part 16 relative to the rolling part 21, and pulls the strip 1A downstream. That is, the pulling part 22 pulls the strip 1A toward the side where the winding part 25 is located. The pulling part 22 includes a pair of pulling rollers 35 and 36. The pulling rollers 35 and 36 are formed of rubber, for example, and the coefficient of friction in the pulling rollers 35 and 36 is greater than the coefficient of friction of the guide rollers 27A to 27C and 28 and the pressure rollers 31 and 32.

[0037] In the pulling section 22, the pulling roller 35 abuts against the strip 1A from one side in the thickness direction, and the pulling roller 36 abuts against the strip 1A from the side opposite to the pulling roller 35 in the thickness direction. Thus, in the pulling section 22, with the strip 1A held between the pulling rollers 35 and 36, the strip 1A is pulled downstream of the conveying section 16. By being pulled downstream by the pulling section 22, tension in the length direction is applied to the strip 1A (current collector 2) between the pulling section 22 and the rolling section 21. Therefore, the strip 1A, with tension applied in the length direction, is conveyed via guide rollers 27A to 27C between the pulling section 22 and the rolling section 21.

[0038] The elongation section 23 is disposed in the conveying section 16 between the rolling section 21 and the drawing section 22. Figure 3In one example, the elongated portion 23 is formed by guide roller 27B. However, in the following description, it is assumed that the elongated portion 23 is formed by guide roller 27B, but it can also be formed by any one of guide rollers 27A or 27C. The elongated portion 23 can be formed by a roller such as a guide roller for conveying the strip 1A, located between the rolling section 21 and the drawing section 22. In either case, the configuration of the elongated portion 23 and the processing performed on it are the same as when the elongated portion 23 is formed by guide roller 27B.

[0039] Figure 5 This illustrates an example of the structure of the elongated portion 23. Figure 5 In the diagram, the strip-shaped body 1A is represented by a cross-section or approximately orthogonal to the length direction. Figure 5 In one example, the elongation section 23 includes a guide roller 27B, which has a rotation axis (central axis) R. The guide roller 27B is capable of rotating around the rotation axis R. The guide roller 27B has axial directions along the rotation axis R and circumferential directions about the rotation axis R. In the conveying section 16, the strip 1A is conveyed with the rotation axis R of the guide roller 27B aligned with the width direction of the strip 1A. Therefore, the axial direction of the guide roller 27B is aligned with or approximately aligned with the width direction of the conveying section 16.

[0040] The elongated portion 23 has a protrusion 40 formed on the outer periphery of the guide roller 27B. The protrusion 40 protrudes outward from the outer periphery of the guide roller 27B. Furthermore, the protrusion 40 is formed throughout the entire circumference of the guide roller 27B (the direction around the rotation axis R). The protrusion 40 is formed at one end of the guide roller 27B on the axially upward side. Additionally, in… Figure 5 In the diagram, guide roller 27B is shown in a cross section that is parallel or approximately parallel to the axial direction (rotation axis R).

[0041] While the strip 1A is being conveyed via the guide roller 27B, the protrusion 40 is positioned on the side of the long side 7 relative to the coating end 10 containing the active material layer 3 in the width direction of the strip 1A. That is, in the axial direction of the guide roller 27B, the protrusion 40 is positioned on the side of the uncoated area 12 protruding relative to the coating end 10 containing the active material layer 3. The protrusion 40, which applies tension in the length direction to the strip 1A being pulled 22, abuts against the uncoated area 12 of the current collector 2 from the thickness direction side and presses the uncoated area 12 from the thickness direction side. By being pressed by the protrusion 40 under tension, the current collector 2 is stretched along the length direction in the uncoated area 12 by the pressure from the protrusion 40.

[0042] When the strip 1A is being conveyed via the elongation section 23, as described above, the protrusion 40, in the width direction of the strip 1A, is located on the side protruding from the uncoated area 12 relative to the coated end 10 containing the active material layer 3. Therefore, the protrusion 40 does not abut against the coated area 11 containing the active material layer 3 and the current collector 2, and does not press against the coated area 11 of the current collector 2. Therefore, in the elongation section 23, the coated area 11 of the current collector 2 is not elongated in the length direction.

[0043] As described above, in this embodiment, when tension is applied to the strip 1A (current collector 2) in the length direction, the protrusion 40 presses only on the uncoated area 12, thereby stretching the current collector 2 in the length direction only in the uncoated area 12. By stretching the current collector 2 in the length direction only in the uncoated area 12, the aforementioned bending caused by the rolling of the active material layer 3 is corrected. Furthermore, when the active material layer 3 is coated only on one of the pair of main surfaces 5 and 6 in the coated area 11, the protrusion 40 presses on the uncoated area 12 from the side facing the main surface (the corresponding one of 5 and 6) coated with the active material layer 3 in the thickness direction of the strip 1A.

[0044] The protrusion 40 has a protruding end, and a protruding length H is defined in the protrusion 40 up to the protruding end. Additionally, the protrusion 40 has a protruding end face 41 forming the protruding end. In the protrusion 40, the distance from the root of the protrusion to the protruding end face 41 is called the protruding length H. The protruding end face 41 is formed throughout the entire circumference of the guide roller 27B. In this embodiment, the protruding length H of the protrusion 40 is larger than the thickness ta of the active material layer 3 after being rolled by the rolling section 21. Figure 5 As shown in one example, when the active substance layer 3 is formed on both main surfaces 5 and 6 in the coating area 11, the protrusion length H of the protrusion 40 is greater than the thickness of the active substance layer 3 coated on the main surface 5 and the thickness of the active substance layer 3 coated on the main surface 6, respectively. Furthermore, the protrusion length H of the protrusion 40 is preferably more than 2 times and less than 15 times the thickness ta of the active substance layer 3.

[0045] In the protrusion 40, one end of the protrusion 40 is formed axially on the guide roller 27B via a protrusion side 42. The protrusion side 42 is formed throughout the entire circumference of the guide roller 27B. Figure 5 In one example, the protruding side 42 extends radially along the guide roller 27B and faces outward in the axial direction of the guide roller 27B. When the strip 1A is being processed via the guide roller 27B, the protruding side 42 protrudes towards the uncoated area 12 in the width direction of the strip 1A, facing the opposite side to the side containing the active substance layer 3.

[0046] The protruding end face 41 extends from the protruding side face 42 along the axial direction of the guide roller 27B. When the strip 1A is being conveyed via the guide roller 27B, the protruding end face 41 extends from the protruding side face 42 in the width direction of the strip 1A toward the side containing the active material layer 3. The protruding end face 41 is formed over a predetermined width dimension w0 along the axial direction of the guide roller 27B. The predetermined width dimension w0 of the protruding end face 41 is preferably greater than 0 mm and less than 15 mm.

[0047] Furthermore, in the protrusion 40, a protrusion amount variation portion 43 is formed adjacent to the protruding end face 41 from one side of the guide roller 27B in the axial direction. The protrusion amount variation portion 43 is adjacent to the protruding end face 41 from the side opposite to the side where the protruding side face 42 is located in the axial direction of the guide roller 27B. The protrusion amount variation portion 43 is formed throughout the entire circumference of the guide roller 27B. In the protrusion amount variation portion 43, the protrusion amount of the outer circumferential surface of the guide roller 27B decreases in the axial direction of the guide roller 27B toward the side separated from the protruding end face 41. Therefore, in the protrusion amount variation portion 43, the protrusion amount decreases in the axial direction of the guide roller 27B toward the side opposite to the side where the protruding side face 42 is located.

[0048] When the strip 1A is being conveyed via the guide roller 27B, i.e., when the uncoated area 12 of the current collector 2 is pressed by the protrusion 40, the protrusion amount variation section 43 is located between the protruding end face 41 of the protrusion 40 and the active material layer 3 in the width direction of the strip 1A. Furthermore, when the uncoated area 12 of the current collector 2 is pressed by the protrusion 40, the protrusion amount of the protrusion amount variation section 43 decreases in the width direction of the strip 1A towards the side containing the active material layer 3. In the protrusion amount variation section 43, the protrusion length of the protrusion 40 decreases from H to 0 as the protrusion amount of the protruding end face 41.

[0049] Figure 6 In the guide roller 27B that constitutes the elongated section 23, the protrusion 40 and its vicinity are shown. Figure 6 This shows the state of the uncoated area 12 of the current collector 2 being pressed by the protrusion 40. Additionally, in Figure 6 In this embodiment, the strip 1A is shown in a cross-section orthogonal or substantially orthogonal to the length direction, and the guide roller 27B is shown in a cross-section parallel or substantially parallel to the rotation axis R. The protrusion 40 in this embodiment is formed as a multi-level protruding structure, having multiple stepped portions M. Figure 5 as well as Figure 6 In one example, four stepped portions M1 to M4 are provided on the protrusion 40. In addition, the following description describes the case where four stepped portions M1 to M4 are provided, but the configuration of the protrusion 40 described below can also be applied to the case where the number of stepped portions M provided on the protrusion 40 is two or three, or the case where the number of stepped portions M provided on the protrusion 40 is five or more.

[0050] Stepped portions M1 to M4 are formed throughout the circumference of guide roller 27B. The four stepped portions M1 to M4 are arranged sequentially from the inner circumference to the outer circumference of guide roller 27B. Among the stepped portions M1 to M4, the steps located on the outermost circumference of guide roller 27B have a larger protrusion. Furthermore, among the stepped portions M1 to M4, the outermost stepped portion M4 forms the protruding end face 41 of the protrusion 40. Therefore, the protrusion of the outermost stepped portion M4 is the protrusion length H of the protrusion 40. The stepped portions on the inner circumference of the first stage are adjacent to the stepped portions M2 to M4 (excluding the innermost stepped portion M1) on the side opposite to the side containing the protrusion side 42 in the axial direction of guide roller 27B. For example, the stepped portion M3 is adjacent to the stepped portion M4 on the side opposite to the side where the protruding side 42 is located in the axial direction of the guide roller 27B. In addition, among the stepped portions M1 to M3, the stepped portion closer to the inner circumference is located further away from the stepped portion M4 on the outermost circumference in the axial direction of the guide roller 27B.

[0051] With the uncoated area 12 of the current collector 2 pressed by the protrusion 40, the stepped portions on the inner circumferential side of the first stage are adjacent to stepped portions M2 to M4 on the side containing the active material layer 3 in the width direction of the strip 1A. Furthermore, with the uncoated area 12 of the current collector 2 pressed by the protrusion 40, among the stepped portions M1 to M4, the stepped portions closer to the inner circumferential side are located closer to the active material layer 3 (coating end 10) in the width direction of the strip 1A (axial direction of the guide roller 27B). Therefore, among the stepped portions M1 to M4, stepped portion M1 is located closest to the active material layer 3 in the width direction of the strip 1A, and stepped portion M4 is located furthest from the active material layer 3 in the width direction of the strip 1A.

[0052] Each of the stepped portions M1 to M4 has an extending surface (outer peripheral surface) 45 and a step difference forming surface 46. In each of the stepped portions M1 to M4, the extending surface 45 and the step difference forming surface 46 are formed throughout the entire circumference of the guide roller 27B. The extending surface 45 of each of the stepped portions M1 to M4 faces the outer peripheral side of the guide roller 27B. In the protrusion 40, the extending surface 45 of the outermost stepped portion M4 becomes a protruding end face 41. The extending surface 45 of each of the stepped portions M1 to M4 extends along the axial direction of the guide roller 27B.

[0053] Furthermore, in each of the stepped portions M1 to M4, the step difference forming surface 46 faces the side opposite to the side where the protruding side 42 is located in the axial direction of the guide roller 27B. When the uncoated area 12 of the current collector 2 is pressed by the protrusion 40, the step difference forming surface 46 of each of the stepped portions M1 to M4 faces the side containing the active material layer 3 in the width direction of the strip 1A. In each of the stepped portions M1 to M4, the step difference forming surface 46 extends radially along the guide roller 27B, and the outer peripheral end of the step difference forming surface 46 is connected to the extending surface 45. Moreover, in each of the stepped portions M2 to M4 other than the innermost stepped portion M1, the inner peripheral end of the step difference forming surface 46 is connected to the extending surface 45 of the first-level inner peripheral stepped portion. Additionally, in the stepped portion M1, the inner peripheral end of the step difference forming surface 46 is located at the protruding root of the protrusion 40. In each of the stepped portions M2 to M4, a step difference h is formed by a step difference forming surface 46 relative to the stepped portion on the inner circumferential side of the first stage. Furthermore, in stepped portion M1, a step difference h is formed by the step difference forming surface 46 relative to the root position of the protrusion 40.

[0054] The step difference h generated by the multiple stepped sections M1 to M4 can be the same size relative to each other, or it can be different sizes relative to each other. However, the step difference h generated by the multiple stepped sections M1 to M4 is preferably greater than 1 and less than 5 times the thickness ta of the rolled active material layer 3.

[0055] In this embodiment, a protrusion variation section 43 is formed by the step difference forming surface 46 of the outermost stepped portion M4 and the stepped portions M1 to M3 other than the outermost stepped portion M4. In the protrusion variation section 43, the protrusion amount varies based on the same amount of variation as the step difference h formed by the step difference forming surface 46 of each of the stepped portions M1 to M4. Therefore, in the protrusion variation section 43, the protrusion amount on the outer peripheral surface of the guide roller 27B decreases in a step-like manner in the axial direction of the guide roller 27B toward the side separated from the protruding end face 41 and the protruding side face 42. Moreover, when the uncoated area 12 of the current collector 2 is pressed by the protrusion 40, the protrusion amount of the protrusion variation section 43 decreases in a step-like manner in the width direction of the strip 1A toward the side containing the active material layer 3. That is, in the protrusion amount change section 43, in the step difference forming surface 46 of each of the step sections M1 to M4, the protrusion amount decreases in the width direction of the strip body 1A toward the side containing the active substance layer 3.

[0056] Furthermore, the stepped portions M1 to M4 are each formed along the axial direction of the guide roller 27B (the width direction of the strip 1A when it is being conveyed), extending to a width dimension w. The width dimension w of the outermost stepped portion M4 is the same as the width dimension w0 of the protruding end face 41. The width dimensions w of the multiple stepped portions M1 to M4 can be the same size relative to each other or different sizes relative to each other. Preferably, the width dimension w of each stepped portion M1 to M4 is greater than 0 mm and less than 15 mm, similar to the width dimension w0 of the protruding end face 41.

[0057] As described above, in this embodiment, the protrusion length H of the protrusion 40 in pressing the uncoated area 12 of the current collector 2, up to the protruding end, is greater than the thickness ta of the active material layer 3 after being rolled by the rolled portion 21. Therefore, even for a strip 1A with a large dimension b of the uncoated area 12 in the width direction of the current collector 2, pressing the uncoated area 12 of the current collector 2 with the protrusion 40 applying tension in the length direction causes the uncoated area 12 to be appropriately elongated in the length direction. Thus, even for strips 1A with a dimension b greater than 25 mm, or strips 1A with a large dimension b of the uncoated area 12 in the width direction of the current collector 2, the bending of the strip 1A caused by the rolling of the active material layer 3 can be appropriately corrected.

[0058] Furthermore, by making the protruding length H of the protrusion 40 more than twice (200%) the thickness ta of the rolled active material layer 3, the uncoated area 12 is further appropriately elongated along its length by the pressure from the protrusion 40. This further appropriately corrects the bending of the strip 1A caused by the rolling of the active material layer 3. Additionally, by making the protruding length H of the protrusion 40 less than 15 times (1500%) the thickness ta of the rolled active material layer 3, damage to the uncoated area 12 of the current collector 2 caused by the pressure of the protrusion 40 is effectively prevented.

[0059] Furthermore, in the protrusion 40 of this embodiment, a protruding end face 41 and a protrusion amount variation portion 43 are provided as described above. Moreover, when the uncoated area 12 of the current collector 2 is pressed by the protrusion 40, the protrusion amount variation portion 43 is located between the protruding end face 41 and the active material layer 3 in the width direction of the strip 1A. In the protrusion amount variation portion 43, the protrusion amount decreases in the width direction of the strip 1A towards the side containing the active material layer 3. By using the protrusion 40, which is provided with the protruding end face 41 and the protrusion amount variation portion 43, to press the uncoated area 12 as described above, the uncoated area 12 is further appropriately elongated in the length direction. As a result, the bending of the strip 1A caused by the rolling of the active material layer 3 is further appropriately corrected. Additionally, in embodiments such as the present invention, by setting the predetermined width dimension w0 of the protruding end face 41 in the axial direction of the guide roller 27B to 15 mm or less, the uncoated area 12 is further appropriately elongated in the length direction.

[0060] Furthermore, in this embodiment, multiple stepped portions M1 to M4 are formed in the protrusion 40 as described above, and the outermost stepped portion M4 forms a protruding end face 41. Moreover, in the protrusion amount variation portion 43 of the protrusion 40, the protrusion amount decreases in a stepped manner toward the side separated from the protruding end face 41 in the axial direction of the guide roller 27B due to the step difference formed by the multiple stepped portions M1 to M4. As described above, in this embodiment, by providing multiple stepped portions M1 to M4, the step difference h of each stepped portion M1 to M4 is utilized to appropriately form the protrusion amount variation portion 43 in the protrusion 40.

[0061] Furthermore, by making the step difference h generated by the multiple stepped portions M1 to M4 each greater than 1 (100%) of the thickness ta of the rolled active material layer 3, the uncoated area 12 is further appropriately elongated along the length direction by the pressure from the protrusion 40. This further appropriately corrects the bending of the strip 1A caused by the rolling of the active material layer 3. Additionally, by making the step difference h generated by the multiple stepped portions M1 to M4 each less than 5 (500%) of the thickness ta of the rolled active material layer 3, damage to the uncoated area 12 of the current collector 2 caused by the pressure from the protrusion 40 is effectively prevented. Furthermore, by setting the width w of each of the stepped portions M1 to M4 along the axial direction of the guide roller 27B to 15 mm or less, the uncoated area 12 is appropriately elongated along the length direction.

[0062] exist Figure 7In the modified example shown, multiple stepped portions M1 to M4 are also formed on the protrusion 40. However, in this modified example, in each of the stepped portions M1 to M4, a curved surface (chamfered portion) 47 is formed between the extending surface (outer peripheral surface) 45 and the step difference forming surface 46. In each of the stepped portions M1 to M4, the curved surface 47 is formed throughout the entire circumference of the guide roller 27B (in the direction about the axis of rotation R). Furthermore, Figure 7 In the guide roller 27B that constitutes the elongated section 23, the protrusion 40 and its vicinity are shown. Furthermore, Figure 7 This shows the state of the uncoated area 12 of the current collector 2 being pressed by the protrusion 40. Additionally, in Figure 7 In the diagram, the strip 1A is shown in a cross section orthogonal or approximately orthogonal to the length direction, and the guide roller 27B is shown in a cross section parallel or approximately parallel to the rotation axis R.

[0063] like Figure 7 As shown, in a cross-section parallel or substantially parallel to the rotation axis R, the curved surface 47 of each of the stepped portions M1 to M4 is an arc shape or a substantially arc shape. Furthermore, the center of the arc shape or substantially arc shape of the curved surface 47 of each of the stepped portions M1 to M4 is located on the side where the protruding side 42 is located, and on the inner circumference of the guide roller 27B, relative to the curved surface 47. Additionally, the radius of curvature r of the curved surface 47 of each of the stepped portions M1 to M4 is preferably 0.5 mm or more and 7 mm or less.

[0064] In this modified example, the same function and effect are achieved as in the embodiments described above. That is, even for a strip 1A with a large dimension b of the uncoated area 12 in the width direction of the current collector 2, the bending of the strip 1A caused by the rolling of the active material layer 3 can be appropriately corrected. In addition, in this modified example, by setting the radius of curvature r of the curved surface 47 of each of the stepped portions M1 to M4 to be 7 mm or less, the uncoated area 12 is further appropriately elongated in the length direction by the pressing from the protrusion 40. As a result, the bending of the strip 1A caused by the rolling of the active material layer 3 is further appropriately corrected. Furthermore, by setting the radius of curvature r of the curved surface of each of the multiple stepped portions M1 to M4 to be 0.5 mm or more, damage to the uncoated area 12 of the current collector 2 caused by the pressing of the protrusion 40 is effectively prevented.

[0065] exist Figure 8 In another variation shown, the protrusion 40 does not form a multi-level protrusion structure, but rather a first-level protrusion structure. Here, Figure 8 In the guide roller 27B that constitutes the elongated section 23, the protrusion 40 and its vicinity are shown. Furthermore, Figure 8 This shows the state of the uncoated area 12 of the current collector 2 being pressed by the protrusion 40. Additionally, in Figure 8In the diagram, the strip 1A is shown in a cross section orthogonal or approximately orthogonal to the length direction, and the guide roller 27B is shown in a cross section parallel or approximately parallel to the rotation axis R.

[0066] like Figure 8 As shown, in this modified example, the protrusion length H of the protrusion 40 up to the protruding end (protruding end face 41) is greater than the thickness ta of the active material layer 3 after being rolled by the rolling section 21. Furthermore, the protrusion length H of the protrusion 40 is preferably more than 2 times and less than 15 times the thickness ta of the active material layer 3. In this modified example, as in the embodiment described above, the protruding end face 41 and the protrusion amount variation portion 43 are formed on the protrusion 40. Moreover, the protruding end face 41 is formed along a predetermined width dimension w0 in the axial direction of the guide roller 27B, and the predetermined width dimension w0 of the protruding end face 41 is preferably greater than 0 mm and less than 15 mm.

[0067] However, in this modified example, the protrusion amount variation section 43 in the protrusion 40 is formed by an inclined surface 51. The inclined surface 51 is formed throughout the entire circumference of the guide roller 27B. In addition, the inclined surface 51 is inclined in both the axial direction and the radial direction of the guide roller 27B. In the protrusion amount variation section 43, through the inclined surface 51, the protrusion amount of the outer peripheral surface of the guide roller 27B decreases in a sloping manner in the axial direction of the guide roller 27B toward the side separated from the protrusion end face 41 and the protrusion side surface 42. Moreover, when the uncoated area 12 of the current collector 2 is pressed by the protrusion 40, the protrusion amount of the protrusion amount variation section 43 decreases in a sloping manner in the width direction of the strip 1A toward the side containing the active material layer 3. In this modified example, in the protrusion amount variation section 43, the protrusion amount decreases from the protrusion length H of the protrusion 40, which is the protrusion amount of the protrusion end face 41, to 0.

[0068] Furthermore, in a certain modified example, the protrusion variation portion 43 formed by the stepped portions M1 to M4 or the inclined surface 51 is not formed on the protrusion 40. In this modified example, the protrusion length H of the protrusion 40 up to the protruding end (protruding end face 41) is also greater than the thickness ta of the active material layer 3 after being rolled by the rolling portion 21. In addition, the protrusion length H of the protrusion 40 is preferably more than 2 times and less than 15 times the thickness ta of the active material layer 3. In addition, in the protrusion 40, the protruding end face 41 is formed along a predetermined width dimension w0 in the axial direction of the guide roller 27B, and the predetermined width dimension w0 of the protruding end face 41 is preferably greater than 0 mm and less than 15 mm.

[0069] In any of the above-described modifications, the protrusion length from the protrusion 40 to the protruding end (protruding end face 41) is greater than the thickness ta of the active material layer 3 after being rolled by the H-rolling section 21. Therefore, in any of these modifications, the same function and effect as in the embodiments described above are achieved. That is, even if the strip 1A has a large dimension b of the uncoated area 12 in the width direction of the current collector 2, the bending of the strip 1A caused by the rolling of the active material layer 3 can be appropriately corrected.

[0070] (Verification related to implementation methods, etc.)

[0071] In addition, verification related to the above-described embodiments was performed. The verification will be described below. In the verification, an active material layer was coated onto the surface of the current collector to form a strip. Aluminum foil was used as the current collector. Furthermore, in the coating process onto the surface of the current collector, a slurry was prepared by suspending the active material, conductive agent, and binder in an organic solvent. LiNi with an average primary particle diameter of 2 μm was used as the active material. 0.5 Co 0.2 Mn 0.3 O2 composite oxide was used as the conductive agent, graphite powder was used as the binder, and polyvinylidene fluoride (PVdF) was used as the binder. N-methyl-2-pyrrolidone (NMP) was used as the organic solvent. In the slurry preparation, the proportions were set as follows: active material 90% by mass, conductive agent 5% by mass, and binder 5% by mass. The prepared slurry was then coated onto the surface of the current collector. At this point, one of the pair of long sides of the current collector and its vicinity were not coated with slurry. Thus, in the strip, a coated area with an active material layer coated on both sides of the pair of main surfaces and an uncoated area without an active material layer coated on either side of the pair of main surfaces were formed. The uncoated area in the current collector was formed on one of the pair of long sides and its vicinity.

[0072] In the verification, after forming the strip as described above, the active material layer (slurry) coated on the surface of the current collector was dried. Furthermore, in conjunction with... Figure 3 In a similar conveying section, as in the embodiments described above, a strip is conveyed. Furthermore, through... Figure 3 In a similar rolling section, the layer containing the active material is rolled using a roller press within the conveyed strip. Additionally, downstream of the rolling section, a process is performed with... Figure 3 In a similar example, the pulling section pulls the strip downstream. This applies a length-direction tension to the strip between the pulling section and the rolling section. Furthermore, in the verification, at a point equivalent to... Figure 3In one example, the guide roller 27B has protrusions on its outer peripheral surface. The protrusions and the roller forming the protrusions on the outer peripheral surface are made of stainless steel. Moreover, as in the embodiments described above, for a strip under tension, the protrusions press against the uncoated area of ​​the current collector, causing the uncoated area to elongate along its length.

[0073] In the verification, after elongating the uncoated area by using protrusions, through... Figure 4 In one example of the measurement method, the bending amount η of the strip was measured. In this case, the specified distance D was set to 1000 mm, and two points P1 and P2 were determined on the long side opposite to the uncoated area of ​​the current collector, with a straight-line distance equal to the specified distance D.

[0074] In the verification, under the conditions of Examples 1 to 7 and Comparative Example 1 described below, the above-described process, including the elongation of the uncoated area caused by the protrusions, was performed, and the bending amount η of the strip was measured. Furthermore, in Examples 1 to 7 and Comparative Example 1, the pressure (stamping) applied to the active material layer in the rolling section and the pulling force applied to pull the strip downstream in the drawing section were set to be the same for each other. Figure 9 The measurements of the bending amount η in Examples 1 to 7 and Comparative Example 1, which are related to the implementation methods, are shown.

[0075] like Figure 9 As shown in Examples 1 to 7, with Figure 5 as well as Figure 6 Similarly, in one example, a protrusion is formed in a multi-level protrusion structure having multiple stepped portions. In Example 1, the protrusion length H of the protrusion up to the protrusion end (protrusion end face) is set to 2.4 times the thickness ta of the rolled active material layer. Furthermore, the number of stepped portions in the protrusion is set to 2 levels, and the width w of each stepped portion is set to 15 mm. Therefore, the predetermined width w0 of the protrusion end face corresponding to the width w of the outermost stepped portion is 15 mm. Additionally, the step difference h of each stepped portion is set to 1.2 times the thickness ta of the rolled active material layer. Moreover, in the strip, the dimension of the uncoated area in the width direction of the strip is set to 30 mm.

[0076] In Example 2, the settings are as follows: the protruding length H is set to 6 times the thickness ta, the number of steps is set to 5, the width w is set to 6 mm, the step difference h is set to 1.2 times the thickness ta, and the dimension b is set to 30 mm. In Example 3, the settings are as follows: the protruding length H is set to 10.8 times the thickness ta, the number of steps is set to 9, the width w is set to 3 mm, the step difference h is set to 1.2 times the thickness ta, and the dimension b is set to 30 mm. In Example 4, the settings are as follows: the protruding length H is set to 10 times the thickness ta, the number of steps is set to 5, the width w is set to 6 mm, the step difference h is set to 2 times the thickness ta, and the dimension b is set to 30 mm. In Example 5, the settings are as follows: the protruding length H is set to 14.4 times the thickness ta, the number of steps is set to 12, the width w is set to 2.5 mm, the step difference h is set to 1.2 times the thickness ta, and the dimension b is set to 30 mm. In Example 6, the settings are as follows: the protruding length H is set to 15 times the thickness ta, the number of steps is set to 3, the width w is set to 10 mm, the step difference h is set to 5 times the thickness ta, and the dimension b is set to 30 mm. In Example 7, the settings are as follows: the protruding length H is set to 15 times the thickness ta, the number of steps is set to 10, the width w is set to 6 mm, the step difference h is set to 1.5 times the thickness ta, and the dimension b is set to 60 mm.

[0077] In Comparative Example 1, a protrusion is formed in the first-level protrusion structure. Therefore, the number of steps is one level. Moreover, the configuration corresponding to the protrusion amount variation section 43 in the above embodiment is not formed in the protrusion. In addition, the protrusion length H of the protrusion up to the protrusion end (protrusion end face) is set to 1 times the thickness ta of the rolled active material layer. In Comparative Example 1, since the number of steps is one level, by making the protrusion length H 1 times the thickness ta, the step difference h of the steps is also 1 times the thickness ta. In addition, the width w of the steps is set to 30 mm. In Comparative Example 1, since the width w of the steps corresponds to the predetermined width w0 of the protrusion end face, by setting the width w to 30 mm, the predetermined width w0 of the protrusion end face is also 30 mm. In addition, in the strip, the dimension b of the uncoated area in the width direction of the strip is set to 30 mm.

[0078] Regarding the bending amount η of the strip after the uncoated area is stretched along its length by the protrusions, it is 0.7 mm in Example 1, 0.3 mm in Example 2, 0.2 mm in Example 3, 0.3 mm in Example 4, 0.1 mm in Example 5, 0.6 mm in Example 6, 0.2 mm in Example 7, and 1.5 mm in Comparative Example 1. In Examples 1 to 7, the bending amount η is smaller compared to Comparative Example 1. Therefore, it is confirmed that, compared to cases where the protrusion length H is less than or equal to the thickness ta of the rolled active material layer 3, by making the protrusion length H greater than the thickness ta of the active material layer 3, the bending of the strip caused by the rolling of the active material layer can be appropriately corrected.

[0079] According to at least one of the above embodiments or examples, tension in the length direction is applied to the strip between the rolling section that rolls the active material layer and the pulling section that pulls the strip. Furthermore, by using a protrusion extending outward from the outer periphery of the roller between the rolling section and the pulling section, the uncoated area of ​​the current collector is pressed, thereby elongating the uncoated area along the length direction. Moreover, the protrusion length of the protrusion up to the protruding end is greater than the thickness of the rolled active material layer. Therefore, a method and apparatus for manufacturing an electrode structure can be provided that can appropriately correct the bending of the strip caused by rolling the active material layer, even if the size of the uncoated area in the width direction of the current collector becomes larger.

[0080] Furthermore, the above-described implementation methods can be summarized as the following technical solutions.

[0081] Technical Solution 1

[0082] A method for manufacturing an electrode structure, comprising:

[0083] The strip is conveyed, in which an active material layer is coated on the surface of a current collector, and in the current collector, an uncoated area without an active material layer is formed on one of a pair of long sides along the length direction and in its vicinity.

[0084] The active material layer is rolled in the conveyed strip.

[0085] Downstream of the rolling section where the active material layer is rolled, the strip is pulled downstream, thereby applying tension in the length direction to the strip between the pulling section and the rolling section; and

[0086] By utilizing the protrusions extending outward from the roller between the rolling section and the pulling section, the uncoated area of ​​the current collector is pressed against the strip under tension, thereby elongating the uncoated area along the length direction, and the uncoated area is pressed by the protrusions extending to the protruding end, the length of which is greater than the thickness of the active material layer after being rolled by the rolling section.

[0087] Technical Solution 2

[0088] In the manufacturing method of technical solution 1,

[0089] The strip is conveyed with the rotation axis of the roller along the width direction of the strip.

[0090] In the protrusion, the protruding end face, which becomes the protruding end, is formed along a predetermined width dimension in the axial direction along the rotation axis of the roller.

[0091] In the protrusion, a protrusion variation portion is formed adjacent to the protruding end face from one side of the axial direction, and the protrusion amount of the protrusion variation portion decreases in the axial direction of the roller toward the side separated from the protruding end face.

[0092] When the current collector is pressed by the protrusion into the uncoated area, the protrusion variation portion is located between the protruding end face of the protrusion and the active material layer in the width direction of the strip, and the protrusion amount of the protrusion variation portion decreases in the width direction of the strip toward the side where the active material layer is located.

[0093] Technical Solution 3

[0094] In the manufacturing method of technical solution 2,

[0095] In the protrusions, multiple stepped portions are formed, with the protrusion increasing the further the stepped portion is located on the outer periphery of the roller.

[0096] In the protrusion, the outermost stepped portion among the plurality of stepped portions forms the protruding end face. Through the step difference formed by the plurality of stepped portions, the protrusion amount of the protrusion amount variation portion of the protrusion decreases in a step-like manner in the axial direction of the roller toward the side separated from the protruding end face.

[0097] Technical Solution 4

[0098] In the manufacturing method of technical solution 3,

[0099] In the protrusion, the step difference generated by the plurality of stepped portions is greater than 1 and less than 5 times the thickness of the rolled active material layer.

[0100] Technical Solution 5

[0101] In the manufacturing method of technical solution 2,

[0102] In the protrusion, the specified width dimension of the protruding end face is greater than 0 mm and less than 15 mm.

[0103] Technical Solution 6

[0104] In any of the manufacturing methods in technical solutions 1 to 5,

[0105] In the protrusion, the protrusion length up to the protruding end is more than 2 times and less than 15 times the thickness of the rolled active material layer.

[0106] Technical Solution 7

[0107] In any of the manufacturing methods in technical solutions 1 to 5,

[0108] During the application of the active material layer to the surface of the current collector, the active material layer is applied to the current collector when the size of the uncoated area in the width direction of the strip becomes greater than 25 mm.

[0109] Technical Solution 8

[0110] In any of the manufacturing methods of technical solutions 1 to 5, the following features are also included:

[0111] The current collector is formed from any one of aluminum, aluminum alloy, copper, zinc, stainless steel, and titanium.

[0112] Technical Solution 9

[0113] An apparatus for manufacturing an electrode structure, comprising:

[0114] The conveying unit conveys a strip in which an active material layer is coated on the surface of a current collector, and an uncoated area without an active material layer is formed in the current collector on one of a pair of long sides along the length direction and in its vicinity.

[0115] The rolling section rolls the active material layer in the strip conveyed by the conveying section;

[0116] A pulling section, downstream of the rolling section, applies tension in the length direction to the strip by pulling the strip downstream; and

[0117] The elongation section includes a roller and a protrusion protruding outward from the roller, and is disposed between the rolling section and the drawing section. The elongation section presses the uncoated area of ​​the current collector onto the strip under tension through the protrusion, thereby elongating the uncoated area along the length direction. The protrusion length up to the protruding end is greater than the thickness of the active material layer after being rolled by the rolling section.

[0118] While several embodiments of the invention have been described, these embodiments are provided as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, as well as within the scope of the claims and their equivalents.

Claims

1. A method for manufacturing an electrode structure, comprising: The strip is conveyed, in which an active material layer is coated on the surface of a current collector, and in the current collector, an uncoated area without an active material layer is formed on one of a pair of long sides along the length direction and in its vicinity. The active material layer is rolled in the conveyed strip. Downstream of the rolling section where the active material layer is rolled, the strip is pulled downstream, thereby applying tension in the length direction to the strip between the pulling section and the rolling section; and By utilizing the protrusions extending outward from the roller between the rolling section and the drawing section, the uncoated area of ​​the current collector is pressed against the strip under tension, thereby elongating the uncoated area along its length. The uncoated area is pressed further by the protrusions, whose length up to the protruding end is greater than the thickness of the active material layer after being rolled by the rolling section. The strip is conveyed with the rotation axis of the roller along the width direction of the strip. In the protrusion, the protruding end face, which becomes the protruding end, is formed along a predetermined width dimension in the axial direction along the rotation axis of the roller. In the protrusion, a protrusion variation portion is formed adjacent to the protruding end face from one side of the axial direction, and the protrusion amount of the protrusion variation portion decreases in the axial direction of the roller toward the side separated from the protruding end face. When the current collector's uncoated area is pressed by the protrusion, the protrusion variation portion is located between the protruding end face of the protrusion and the active material layer in the width direction of the strip, and the protrusion amount of the protrusion variation portion decreases in the width direction of the strip towards the side containing the active material layer. In the aforementioned protrusions, multiple stepped portions are formed, with the protrusion increasing the further the stepped portion is located on the outer periphery of the roller. In the protrusion, the outermost stepped portion among the plurality of stepped portions forms the protruding end face. The protrusion amount of the protrusion of the varying protrusion portion decreases in a step-like manner along the axial direction of the roller towards the side separating from the protruding end face due to the step difference formed by the plurality of stepped portions. When the current collector is pressed by the protrusion into the uncoated area, the protrusion variation portion formed by the step portion other than the outermost step portion among the plurality of step portions is located on the side of the uncoated area relative to the active material layer in the width direction of the strip.

2. The manufacturing method as described in claim 1, In the protrusion, the step difference generated by the plurality of stepped portions is greater than 1 and less than 5 times the thickness of the rolled active material layer.

3. The manufacturing method as described in claim 1, In the protrusion, the specified width dimension of the protruding end face is greater than 0 mm and less than 15 mm.

4. The manufacturing method according to any one of claims 1 to 3, In the protrusion, the protrusion length up to the protruding end is more than 2 times and less than 15 times the thickness of the rolled active material layer.

5. The manufacturing method according to any one of claims 1 to 3, During the application of the active material layer to the surface of the current collector, the active material layer is applied to the current collector when the size of the uncoated area in the width direction of the strip becomes greater than 25 mm.

6. The manufacturing method according to any one of claims 1 to 3, further comprising: The current collector is formed from any one of aluminum, aluminum alloy, copper, zinc, stainless steel, and titanium.

7. An apparatus for manufacturing an electrode structure, comprising: The conveying unit conveys a strip in which an active material layer is coated on the surface of a current collector, and an uncoated area without an active material layer is formed in the current collector on one of a pair of long sides along the length direction and in its vicinity. The rolling section rolls the active material layer in the strip conveyed by the conveying section; The pulling section, located downstream of the rolling section, applies tension to the strip in the length direction by pulling the strip downstream. as well as The elongation section includes a roller and a protrusion extending outward from the roller, and is disposed between the rolling section and the drawing section. The elongation section, through the protrusion, presses the uncoated area of ​​the current collector onto the strip under tension, thereby elongating the uncoated area along its length. The protrusion length up to the protruding end is greater than the thickness of the active material layer after being rolled by the rolling section. The conveying unit conveys the strip with the rotation axis of the roller in the elongation unit along the width direction of the strip. In the protrusions of the elongated portion, the protruding end face, which becomes the protruding end, is formed along a predetermined width dimension in the axial direction along the rotation axis of the roller. In the protrusion, a protrusion variation portion is formed adjacent to the protruding end face from one side of the axial direction, and the protrusion amount of the protrusion variation portion decreases in the axial direction of the roller toward the side separated from the protruding end face. When the current collector's uncoated area is pressed by the protrusion, the protrusion variation portion is located between the protruding end face of the protrusion and the active material layer in the width direction of the strip, and the protrusion amount of the protrusion variation portion decreases in the width direction of the strip towards the side containing the active material layer. In the aforementioned protrusions, multiple stepped portions are formed, with the protrusion increasing the further the stepped portion is located on the outer periphery of the roller. In the protrusion, the outermost stepped portion among the plurality of stepped portions forms the protruding end face. The protrusion amount of the protrusion of the varying protrusion portion decreases in a step-like manner along the axial direction of the roller towards the side separating from the protruding end face due to the step difference formed by the plurality of stepped portions. When the current collector is pressed by the protrusion into the uncoated area, the protrusion variation portion formed by the step portion other than the outermost step portion among the plurality of step portions is located on the side of the uncoated area relative to the active material layer in the width direction of the strip.

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