Method and apparatus for manufacturing electrode structures

Abstract

To provide a manufacturing method of an electrode structure capable of appropriately correcting a curve of a belt-like member produced by rolling of an active material-containing layer, even if a dimension of an uncoated region increases in a widthwise direction of a current collector.SOLUTION: In a manufacturing method of an electrode structure 1, in a belt-like member in which an uncoated region 12 not coated with an active material-containing layer 3 is formed in one of long edges and its vicinity in a current collector 2, the active material-containing layer 3 is rolled, and a tension in a longitudinal direction is applied to the belt-like member between a pulling unit pulling the belt-like member and a rolling unit rolling the active material-containing layer 3. In the manufacturing method, the uncoated region 12 in the current collector 2 is pushed by a projection 40 projecting to an outer peripheral side in a roller between the rolling unit and the pulling unit, thereby enlarging the uncoated region 12 in the longitudinal direction. A projection length H of the projection 40 to the projection end 41 is larger than a thickness of the rolled active material-containing layer 3.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] Embodiments of the present invention relate to a method and an apparatus for manufacturing an electrode structure.

Background Art

[0002] In a battery such as a secondary battery, electrodes such as a positive electrode and a negative electrode are formed from an electrode structure. The electrode structure includes a current collector and an active material-containing layer applied to the surface of the current collector, and the current collector has a pair of long edges along the longitudinal direction. In the current collector of the electrode structure, an uncoated region where the active material-containing layer is not applied to either of the pair of main surfaces is formed on one of the pair of long edges and its vicinity. In the manufacture of such an electrode structure, the active material-containing layer is applied to the surface of the current collector in a state where an uncoated region where the active material-containing layer is not applied is formed on one of the pair of long edges and its vicinity of the current collector. Then, after drying the active material-containing layer applied to the current collector, in a state where a strip (current collector) with the active material-containing layer applied thereto is being conveyed, the active material-containing layer is rolled by a roll press or the like.

[0003] In the manufacture of the electrode structure, since the active material-containing layer is rolled as described above, in the coated region where the active material-containing layer is applied to at least one of the pair of main surfaces of the current collector, pressure due to rolling is applied, so the current collector is stretched in the longitudinal direction. On the other hand, in the uncoated region of the current collector, since pressure due to rolling is not applied, the current collector is not stretched in the longitudinal direction. Therefore, due to the rolling of the active material-containing layer, the conveyed strip (current collector) is curved in a state where the side where the uncoated region is located becomes the inner side of the curvature.

[0004] In the manufacturing of electrode structures, the curvature of the strip generated by rolling the active material-containing layer is corrected. To correct the curvature of the strip, tension is applied to the strip in the longitudinal direction between the tensioning section and the rolling section by pulling the strip downstream from the rolling section where the active material-containing layer is rolled. Then, protrusions are provided on the outer surface of the guide roller that guides the strip between the rolling section and the tensioning section, and the uncoated area of ​​the current collector is pressed by the protrusions on the strip under tension, thereby stretching the uncoated area in the longitudinal direction and correcting the curvature.

[0005] Depending on the type of battery using electrodes formed from electrode structures, it may be necessary to create a large uncoated area in the width direction of the strip. In the manufacturing of electrode structures, even if the width of the uncoated area in the width direction of the current collector is large, it is required to properly correct the curvature of the strip caused by rolling the active material-containing layer. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2012-174434 [Patent Document 2] Japanese Patent Publication No. 2001-76711 [Patent Document 3] Japanese Patent Publication No. 2017-142915 [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem that the present invention aims to solve is to provide a method and apparatus for manufacturing an electrode structure that can appropriately correct the curvature of a strip-shaped body caused by rolling the active material-containing layer, even when the dimensions of the uncoated area in the width direction of the current collector become large. [Means for solving the problem]

[0008] According to the manufacturing method of the electrode structure of the embodiment, a strip-shaped body is conveyed in which an active material-containing layer is coated on the surface of a current collector, and an uncoated region is formed on one of a pair of long edges along the longitudinal direction of the current collector and in its vicinity, where the active material-containing layer is not coated. In the manufacturing method, the active material-containing layer is rolled on the conveyed strip-shaped body, and tension is applied to the strip-shaped body in the longitudinal direction between the tensioning section and the rolling section by pulling the strip-shaped body downstream of the rolling section in which the active material-containing layer is rolled. In the manufacturing method, the uncoated region of the current collector is pressed against the strip-shaped body to which tension is applied by a projection that protrudes outward on the outer circumference of the roller between the rolling section and the tensioning section, thereby stretching the uncoated region in the longitudinal direction. The uncoated region is pressed by a projection whose protrusion length to the protruding end is greater than the thickness of the active material-containing layer rolled in the rolling section. The strip-shaped material is transported with the roller's rotation axis aligned with the width direction of the strip. In the protrusion, the protruding end face is formed over a predetermined width dimension in the axial direction along the roller's rotation axis. In the protrusion, a protrusion amount change section is formed adjacent to the protruding end face on one side in the axial direction, where the amount of protrusion decreases toward the side away from the protruding end face in the axial direction of the roller. When the protrusion is pressing against the uncoated area of ​​the current collector, the protrusion amount change section is located between the protruding end face of the protrusion and the active material-containing layer in the width direction of the strip, and the amount of protrusion at the protrusion amount change section decreases toward the side where the active material-containing layer is located in the width direction of the strip. Multiple steps are formed on the protrusion such that the amount of protrusion increases with the step located on the outer circumference of the roller, and in the protrusion, the outermost step among the multiple steps forms the protruding end face. The amount of protrusion at the protrusion amount change section of the protrusion decreases in a stepped manner toward the side away from the protruding end face in the axial direction of the roller, due to the step difference formed by each of the multiple steps. When the protrusion is pressing against the uncoated area of ​​the current collector, the entire portion of the protrusion change formed by the steps other than the outermost step among the multiple steps is located on the side of the strip-shaped body where the uncoated area is located relative to the active material-containing layer, in the width direction of the strip-shaped body. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing an example of an electrode structure formed in the embodiment, viewed from one side in the thickness direction. [Figure 2] Figure 2 is a schematic cross-sectional view of the electrode structure shown in Figure 1, with a cross-section perpendicular or nearly perpendicular to the longitudinal direction. [Figure 3] Figure 3 is a schematic diagram showing an example of a manufacturing apparatus for producing an electrode structure in an embodiment. [Figure 4] Figure 4 is a schematic diagram showing an example of a measurement method for measuring the curvature of a strip-shaped body that has been curved by rolling or other processes involving an active material-containing layer. [Figure 5] Figure 5 is a schematic cross-sectional view showing an example of the configuration of the stretching section in the manufacturing apparatus according to the embodiment, with a cross-section parallel or substantially parallel to the axial direction of the guide roller. [Figure 6] Figure 6 is a schematic cross-sectional view of the enlarged portion of Figure 5, showing the protrusions of the guide roller and the configuration of their vicinity in a cross-section parallel or substantially parallel to the axial direction of the guide roller. [Figure 7]Figure 7 is a schematic cross-sectional view showing the configuration of the guide roller projection and its vicinity in the stretching section of a certain modified manufacturing apparatus, with the cross-section being parallel or substantially parallel to the axial direction of the guide roller. [Figure 8] Figure 8 is a schematic cross-sectional view showing the protrusions of the guide roller and the configuration of their vicinity in the stretching section of a manufacturing apparatus for a different modification from that shown in Figure 7, with the cross-section being parallel or substantially parallel to the axial direction of the guide roller. [Figure 9] This is a schematic diagram showing the conditions and measurement results of the curvature amount η in each of Examples 1 to 8 and Comparative Example 1 in verification related to the embodiments. [Modes for carrying out the invention]

[0010] The embodiments and other details will be described below with reference to the drawings.

[0011] In this embodiment, a method for manufacturing an electrode structure and a manufacturing apparatus are provided. The electrode structure manufactured in this embodiment is used to form a positive or negative electrode in a battery such as a secondary battery. Figures 1 and 2 show an example of an electrode structure 1 formed in this embodiment. As shown in Figures 1 and 2, the electrode structure 1 has defined longitudinal direction (direction indicated by arrow L1), width direction (direction indicated by arrow W1) that intersects (orthogonal or approximately orthogonal to) the longitudinal direction, and thickness direction (direction indicated by arrow T1) that intersects (orthogonal or approximately orthogonal to) both the longitudinal and width directions. Figure 1 shows the structure as viewed from one side in the thickness direction, and Figure 2 shows a cross-section that is orthogonal or approximately orthogonal to the longitudinal direction. In the electrode structure 1, the dimensions in the longitudinal direction are larger than the dimensions in the width direction and the dimensions in the thickness direction, and the dimensions in the width direction are larger than the dimensions in the thickness direction.

[0012] In one example, the electrode structure 1 becomes 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 a plurality of electrode sheets in the longitudinal direction. Each of the plurality of electrode sheets is then used as the positive or negative electrode of the battery. The electrode structure 1 comprises a current collector 2 and an active material-containing layer 3 coated on the surface of the current collector 2. The current collector 2 is formed from a conductive metal and comprises a pair of main surfaces 5 and 6 and a pair of long edges 7 and 8. Each of the main surfaces 5 and 6 and the long edges 7 and 8 extends along the longitudinal direction, from one end to the other of the electrode structure 1 in the longitudinal direction. In addition, each of the main surfaces 5 and 6 extends from the long edge 7 to the long edge 8 in 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 of the main surface 5 in the thickness direction of the electrode structure 1.

[0013] The long edge (first long edge) 7 forms one side of the current collector 2 in the width direction of the electrode structure 1. The long edge (second long edge) 8 forms the edge of the current collector 2 opposite to the long edge 7 in the width direction of the electrode structure 1. The active material-containing layer 3 extends from one end to the other of the electrode structure 1 in the longitudinal direction. The active material-containing layer 3 extends from the long edge 8 of the current collector 2 to the coated end 10 in the width direction of the electrode structure 1. The end of the active material-containing layer 3 opposite to the coated end 10 in the width direction of the electrode structure 1 overlaps with the long edge 8 of the current collector 2 when viewed from the thickness direction. The coated end 10 is located on the side where the long edge 7 is located relative to the center of the electrode structure 1 in the width direction. Therefore, the dimension between the long edge 8 and the coated end 10 in the width direction of the electrode structure 1 is larger than the dimension between the long edge 7 and the coated end 10 in the width direction of the electrode structure 1.

[0014] In an example such as FIGS. 1 and 2, a coating region 11 is formed between the long edge 8 and the coating end 10 in the width direction of the electrode structure 1, where the active material-containing layer 3 is coated and supported on both of the pair of main surfaces 5 and 6 of the current collector 2. And an uncoated region 12 is formed between the long edge 7 and the coating end 10 in the width direction of the electrode structure 1, where the active material-containing layer 3 is not coated and supported on either of the pair of main surfaces 5 and 6 of the current collector 2. Therefore, in the current collector 2, an uncoated region 12 where the active material-containing layer 3 is not coated on either of the pair of main surfaces 5 and 6 is formed near the long edge 7 and in its vicinity. In the electrode structure 1, the uncoated region 12 protrudes from the coating end 10 of the active material-containing layer 3 to the side opposite to the side where the long edge 8 is located in the width direction. In addition, in one example, in the coating region 11, the active material-containing layer 3 may be supported on only one of the pair of main surfaces 5 and 6 of the current collector 2. Therefore, in the coating region 11, it is sufficient that the active material-containing layer 3 is coated and supported on at least one of the pair of main surfaces 5 and 6 of the current collector 2.

[0015] When the electrode structure 1 is used for forming a positive electrode, the current collector 2 is formed of, but not limited to, for example, any one of aluminum, aluminum alloy, stainless steel, titanium, etc., and has a thickness of about 10 μm to 30 μm. The active material-containing layer 3 includes a positive electrode active material and may optionally contain a binder and a conductive agent. Examples of the positive electrode active material include, but are not limited to, oxides, sulfides, polymers, etc. that can occlude and release lithium ions. The positive electrode active material includes at least one selected from the group consisting of, for example, lithium manganese composite oxide, lithium nickel composite oxide, lithium cobalt aluminum composite oxide, lithium nickel cobalt manganese composite oxide, spinel-type lithium manganese nickel composite oxide, lithium manganese cobalt composite oxide, lithium iron oxide, lithium fluorinated iron sulfate, lithium iron composite phosphate compound, and lithium manganese composite phosphate compound.

[0016] As the conductive agent, for example, one or more types of carbonaceous substances are used. Examples of the carbonaceous substance serving as the conductive agent include acetylene black, ketjen black, graphite, and coke. Further, as the binder, for example, a polymer resin is used. The binder includes, for example, at least one selected from the group consisting of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorine rubber, ethylene-butadiene rubber, polypropylene (PP), polyethylene (PE), carboxymethyl cellulose (CMC), polyimide (PI), and polyacrylimide (PAI).

[0017] When the electrode structure 1 is used for forming a negative electrode, the current collector 2 is formed of, for example, but not limited to, any of zinc, aluminum, an aluminum alloy, and copper, and has a thickness of about 10 μm to 30 μm. The negative electrode active material-containing layer includes a negative electrode active material and may optionally contain a binder and a conductive agent. The negative electrode active material is not particularly limited, and examples thereof include metal oxides, metal sulfides, metal nitrides, and carbonaceous substances that can occlude and release lithium ions. Examples of the metal oxide serving as the negative electrode active material include titanium-containing oxides. The titanium-containing oxides serving as the negative electrode active material include, for example, titanium oxides, lithium titanium oxides, niobium titanium oxides, and sodium niobium titanium oxides. Examples of the conductive agent and the binder are the same materials as those used when forming a positive electrode.

[0018] In the manufacture of the electrode structure 1, a slurry is prepared by suspending an active material that becomes a positive electrode active material or a negative electrode active material, a conductive agent, and a binder in an organic solvent. At this time, the mixing ratio of the active material, the conductive agent, and the binder is preferably such that the active material is 70% by mass or more and 95% by mass or less, the conductive agent is 3% by mass or more and 20% by mass or less, and the binder is 2% by mass or more and 10% by mass or less. Then, the adjusted slurry is applied to the surface of the current collector 2 to form a strip in which the active material-containing layer 3 is applied to the surface of the current collector 2. The application of the slurry is performed, for example, using an application head.

[0019] In the manufacture of the electrode structure 1, the electrode structure 1 is formed by performing the following steps on the strip-shaped body formed as described above. In the strip-shaped body, similar to the electrode structure 1, the longitudinal direction, width direction and thickness direction are defined, and coated areas 11 and uncoated areas 12 are formed. Therefore, in the strip-shaped body, uncoated areas 12 are formed on the long edge 7 and its vicinity on the current collector 2, where the active material-containing layer 3 is not coated on either of the pair of main surfaces 5 and 6. Also, in the strip-shaped body, in the width direction, coated areas 11 are formed from the long edge 8 of the current collector 2 to the coated end 10 of the active material-containing layer 3, where the active material-containing layer 3 is coated on at least one of the pair of main surfaces 5 and 6 of the current collector 2. In the manufacture of the electrode structure 1, when the active material-containing layer 3 is coated on the current collector 2, the active material-containing layer 3 (slurry) coated on the surface of the current collector 2 is dried.

[0020] Furthermore, depending on the battery using electrodes formed from electrode structure 1, it may be necessary to make the dimension (width) b of the uncoated area 12 in the width direction of the strip-shaped body larger. In one example, the active material-containing layer 3 is coated onto the current collector 2 such that the dimension b of the uncoated area 12 in the width direction of the strip-shaped body (current collector 2) is greater than 25 mm. In this case, the manufactured electrode structure 1 has a dimension b of the uncoated area 12 in the width direction that is greater than 25 mm. However, even when the dimension b of the uncoated area 12 in the width direction of the strip-shaped body is greater than 25 mm, the dimension of the coated area 11 in the width direction is larger than the dimension b of the uncoated area 12 in the width direction.

[0021] Figure 3 shows an example of a manufacturing apparatus 15 for manufacturing an electrode structure 1. Figure 3 shows the process after the active material-containing layer 3 coated on the current collector 2 has been dried during the manufacturing of the electrode structure 1. The example manufacturing apparatus 15 in Figure 3 includes a conveying section 16. In the conveying section 16, a strip-shaped body 1A, on which the active material-containing layer 3 has been coated and which has been dried, is conveyed. In the conveying section 16, the conveying direction (direction indicated by arrow F1) and the width direction intersecting (orthogonal or approximately orthogonal to) the conveying direction are defined. In Figure 3, the direction orthogonal or approximately orthogonal to the plane of the paper is the width direction of the conveying section 16. Also, in the conveying section 16, the side on which the strip-shaped body 1A is conveyed is the downstream side, and the side opposite to the side on which the strip-shaped body 1A is conveyed is the upstream side. In the conveying section 16, the strip-shaped body 1A is conveyed with its longitudinal direction aligned with the conveying direction and its width direction aligned with the width direction of the conveying section 16. Therefore, in the strip-shaped body 1A being conveyed in the conveying section 16, the thickness direction of the strip-shaped body 1A intersects (orthogonal or nearly orthogonal to) both the conveying direction and the width direction of the conveying section 16.

[0022] The manufacturing apparatus 15 in the example shown in Figure 3 comprises a rolling section 21, a tensioning section 22, a stretching section 23, and a winding section 25. In the manufacturing apparatus 15, the strip-shaped body 1A, which has had the active material-containing layer 3 dried, is fed into the rolling section 21. The strip-shaped body 1A is then transported from the rolling section 21 through the stretching section 23 and the tensioning section 22 in that order to the winding section 25. The electrode structure 1 is formed by the processes described later in the rolling section 21, stretching section 23, and tensioning section 22 on the transported strip-shaped body 1A. The winding section 25 winds up the transported strip-shaped body 1A, i.e., the formed electrode structure 1. In the example shown in Figure 3, the winding section 25 is equipped with a winding reel 26, on which the electrode structure 1 (strip-shaped body 1A) is wound into a roll shape. Furthermore, in the example shown in Figure 3, the strip-shaped body 1A is guided from upstream to downstream by three guide rollers (rollers) 27A, 27B, and 27C between the rolling section 21 and the tensioning section 22 of the conveying section 16. Also, between the tensioning section 22 and the winding section 25, the strip-shaped body 1A is guided from upstream to downstream by a guide roller 28. Each of the guide rollers 27A-27C and 28 is formed from a metal such as stainless steel.

[0023] The rolling section 21 rolls the active material-containing layer 3 on the conveyed strip 1A using a roll press or the like. The rolling section 21 is equipped with a pair of press rollers 31 and 32, each of which is made of a metal such as stainless steel. Press roller 31 presses the active material-containing layer 3 from one side in the thickness direction of the strip 1A, and press roller 32 presses the active material-containing layer 3 from the opposite side of the thickness direction of the strip 1A from press roller 31. As a result, the active material-containing layer 3 is sandwiched between the press rollers 31 and 32 in the thickness direction of the strip 1A, and pressure (pressing pressure) in the thickness direction of the strip 1A is applied to the active material-containing layer 3. In this case, if the active material-containing layer 3 is coated on both sides of the current collector 2, the active material-containing layer 3 is pressed while each of the press rollers 31 and 32 is in contact with the active material-containing layer 3. Furthermore, if the active material-containing layer 3 is coated on only one side of the current collector 2, the active material-containing layer 3 is pressed when one of the press rollers 31 and 32 is in contact with the active material-containing layer 3 and the other press roller 31 and 32 is in contact with the coated area 11 of the current collector 2. The pressure from the press rollers 31 and 32 compresses the active material-containing layer 3 in the thickness direction of the strip-shaped body 1A and stretches it in the longitudinal direction of the strip-shaped body 1A.

[0024] Furthermore, the pressure used to roll the active material-containing layer 3 is also applied to the coating region 11 on the current collector 2, where the active material-containing layer 3 is coated on at least one of the pair of main surfaces 5 and 6. As a result, in the coating region 11, the pressure used to roll the active material-containing layer 3 stretches the current collector 2 in the longitudinal direction. On the other hand, the press rollers 31 and 32 do not apply the rolling pressure of the active material-containing layer 3 to the uncoated region 12 of the current collector 2. As a result, the uncoated region 12 of the current collector 2 is not stretched in the longitudinal direction during the rolling of the active material-containing layer 3. As described above, since the current collector 2 is stretched in the longitudinal direction only in the coating region 11, the rolling of the active material-containing layer 3 causes the conveyed strip-shaped body 1A (current collector 2) to curve such that the side where the uncoated region 12 is located is on the inside of the curve.

[0025] Here, the amount of curvature of the strip-shaped body 1A when it is curved as described above can be measured. Figure 4 shows an example of a measurement method for measuring the amount of curvature of a curved strip-shaped body 1A. In the example in Figure 4, as described above, the rolling of the active material-containing layer 3 causes the conveyed strip-shaped body 1A (current collector 2) to curve so that the side where the uncoated region 12 is located becomes the inside of the curve. In the measurement method of the example in Figure 4, two points P1 and P2 are identified at the long edge 8 of the current collector 2, that is, at the end opposite to the coated end 10 of the active material-containing layer 3 in the width direction of the strip-shaped body 1A, where the straight-line distance is a specified distance D. Then, a reference straight line α is defined connecting points P1 and P2, and the amount of protrusion (protrusion dimension) of the long edge 8 (the end opposite to the coated end 10 of the active material-containing layer 3) from the reference straight line α to the outside of the curve is calculated as the amount of curvature η. In other words, the distance from the long edge 8 to the protruding end of the long edge 8 relative to the reference line α is calculated as the curvature amount η. A larger curvature amount η indicates that the strip-shaped body 1A is more curved.

[0026] In this embodiment, the tensioning section 22 and the stretching section 23 correct the curvature of the strip-shaped body 1A (current collector 2) generated by the rolling of the active material-containing layer 3. The tensioning section 22 is positioned downstream of the conveying section 16 relative to the rolling section 21 and pulls the strip-shaped body 1A downstream. That is, the tensioning section 22 pulls the strip-shaped body 1A toward the side where the winding section 25 is located. The tensioning section 22 is equipped with a pair of tensioning rollers 35 and 36. Each of the tensioning rollers 35 and 36 is formed from, for example, rubber, and the tensioning rollers 35 and 36 have a higher coefficient of friction than the guide rollers 27A to 27C, 28 and the press rollers 31 and 32.

[0027] In the tensioning section 22, the tension roller 35 contacts the strip-shaped body 1A from one side in the thickness direction, and the tension roller 36 contacts the strip-shaped body 1A from the opposite side in the thickness direction from the tension roller 35. As a result, in the tensioning section 22, the strip-shaped body 1A is pulled downstream of the conveying section 16 while being sandwiched between the tension rollers 35 and 36. As the strip-shaped body 1A is pulled downstream by the tensioning section 22, longitudinal tension is applied to the strip-shaped body 1A (current collector 2) between the tensioning section 22 and the rolling section 21. Therefore, between the tensioning section 22 and the rolling section 21, the strip-shaped body 1A, with longitudinal tension applied, is conveyed through the guide rollers 27A to 27C.

[0028] The stretching section 23 is provided in the conveying section 16 between the rolling section 21 and the tensioning section 22. In the example shown in Figure 3, the stretching section 23 is formed by a guide roller 27B. In the following description, it is assumed that the stretching section 23 is formed by the guide roller 27B, but the stretching section 23 may be formed by either the guide roller 27A or 27C. The stretching section 23 can be formed between the rolling section 21 and the tensioning section 22 by a roller used for conveying the strip-shaped body 1A, such as a guide roller. In either case, the configuration of the stretching section 23 and the processing performed by the stretching section 23 are the same as when the stretching section 23 is formed by the guide roller 27B.

[0029] Figure 5 shows an example of the configuration of the stretching section 23. In Figure 5, the strip-shaped body 1A is shown in a cross-section perpendicular or approximately perpendicular to the longitudinal direction. In an example such as Figure 5, the stretching section 23 is equipped with a guide roller (roller) 27B, and the guide roller 27B is equipped with a rotation axis (central axis) R. The guide roller 27B is rotatable about the rotation axis R. The guide roller 27B has an axial direction along the rotation axis R and a circumferential direction which is the direction around the rotation axis R. In the conveying section 16, the strip-shaped body 1A is conveyed with the rotation axis R of the guide roller 27B aligned with the width direction of the strip-shaped body 1A. Therefore, the axial direction of the guide roller 27B coincides with or approximately coincides with the width direction of the conveying section 16.

[0030] The extension portion 23 is provided with a projection 40 formed on the outer circumference of the guide roller 27B. On the outer circumference of the guide roller 27B, the projection 40 protrudes outward. Furthermore, the projection 40 is formed around the entire circumference of the guide roller 27B in the circumferential direction (around the axis of rotation R). On the guide roller 27B, the projection 40 is formed at one end in the axial direction. Note that in Figure 5, the guide roller 27B is shown with a cross-section parallel or substantially parallel to the axial direction (axis of rotation R).

[0031] When the strip-shaped body 1A is being conveyed through the guide roller 27B, the projection 40 is positioned on the side of the strip-shaped body 1A where the long edge 7 is located relative to the coated end 10 of the active material-containing layer 3, in the width direction. That is, the projection 40 is positioned on the side of the strip-shaped body 1A where the uncoated region 12 protrudes relative to the coated end 10 of the active material-containing layer 3, in the axial direction of the guide roller 27B. The projection 40 contacts the uncoated region 12 of the current collector 2 from one side in the thickness direction, and presses the uncoated region 12 from one side in the thickness direction, against the strip-shaped body 1A to which tension is applied in the longitudinal direction by the tensioning portion 22. Due to the pressure from the projection 40 while tension is applied, the current collector 2 is stretched in the longitudinal direction in the uncoated region 12 by the pressure from the projection 40.

[0032] As described above, when the strip-shaped body 1A is being transported through the stretching section 23, the projection 40 is positioned in the width direction of the strip-shaped body 1A on the side where the uncoated area 12 protrudes relative to the coated end 10 of the active material-containing layer 3. Therefore, the projection 40 does not come into contact with the coated area 11 of the active material-containing layer 3 or the current collector 2, and does not press against the coated area 11 of the current collector 2. Consequently, the coated area 11 of the current collector 2 is not stretched in the longitudinal direction in the stretching section 23.

[0033] As described above, in this embodiment, when tension is acting longitudinally on the strip-shaped body 1A (current collector 2), the projection 40 presses only on the uncoated area 12, thereby stretching the current collector 2 longitudinally only in the uncoated area 12. By stretching the current collector 2 longitudinally only in the uncoated area 12, the aforementioned curvature caused by the rolling of the active material-containing layer 3 is corrected. In the case where the active material-containing layer 3 is coated on only one of the pair of main surfaces 5 and 6 in the coated area 11, the projection 40 presses on the uncoated area 12 from the side facing the main surface (corresponding one of 5 and 6) to which the active material-containing layer 3 is coated, in the thickness direction of the strip-shaped body 1A.

[0034] The projection 40 has a protruding end, and the projection length H to the protruding end is defined for the projection 40. The projection 40 also has a protruding end surface 41 that forms the protruding end. For the projection 40, the distance from the root position of the projection to the protruding end surface 41 is the projection length H. The protruding end surface 41 is formed around the entire circumference in the circumferential direction of the guide roller 27B. In this embodiment, the projection length H of the projection 40 is greater than the thickness ta of the active material-containing layer 3 rolled by the rolling section 21. As shown in the example in Figure 5, when the active material-containing layer 3 is formed on both of the pair of main surfaces 5 and 6 in the coating area 11, the projection length H of the projection 40 is greater than the thickness of the active material-containing layer 3 coated on the main surface 5 and the thickness of the active material-containing layer 3 coated on the main surface 6, respectively. Furthermore, it is preferable that the projection length H of the projection 40 is 2 times or more and 15 times or less the thickness ta of the active material-containing layer 3.

[0035] In the case of the projection 40, the projection side surface 42 forms one end of the projection 40 in the axial direction of the guide roller 27B. The projection side surface 42 is formed around the entire circumference in the circumferential direction of the guide roller 27B. In the example shown in Figure 5, the projection side surface 42 extends along the radial direction of the guide roller 27B and faces outward in the axial direction of the guide roller 27B. When the strip-shaped body 1A is being conveyed through the guide roller 27B, the projection side surface 42 faces the side where the uncoated area 12 protrudes in the width direction of the strip-shaped body 1A, and faces away from the side where the active material-containing layer 3 is located.

[0036] The protruding end face 41 extends from the projection side surface 42 along the axial direction of the guide roller 27B. When the strip-shaped body 1A is being conveyed through the guide roller 27B, the protruding end face 41 extends from the projection side surface 42 toward the side where the active material-containing layer 3 is located in the width direction of the strip-shaped body 1A. The protruding end face 41 is formed over a predetermined width dimension w0 in 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 15 mm or less.

[0037] Furthermore, in the projection 40, the projection amount change portion 43 is formed adjacent to the projection end face 41 from one side in the axial direction of the guide roller 27B. The projection amount change portion 43 is adjacent to the projection end face 41 from the side opposite to the side where the projection side surface 42 is located in the axial direction of the guide roller 27B. The projection amount change portion 43 is formed around the entire circumference of the guide roller 27B in the circumferential direction. In the projection amount change portion 43, the amount of projection on the outer circumferential surface of the guide roller 27B decreases toward the side away from the projection end face 41 in the axial direction of the guide roller 27B. Therefore, in the projection amount change portion 43, the amount of projection decreases toward the side opposite to the side where the projection side surface 42 is located in the axial direction of the guide roller 27B.

[0038] When the strip-shaped body 1A is being conveyed through the guide roller 27B, that is, when the projection 40 is pressing against the uncoated area 12 of the current collector 2, the projection amount change section 43 is located between the protruding end face 41 of the projection 40 and the active material-containing layer 3 in the width direction of the strip-shaped body 1A. When the projection 40 is pressing against the uncoated area 12 of the current collector 2, the amount of protrusion at the projection amount change section 43 decreases toward the side where the active material-containing layer 3 is located in the width direction of the strip-shaped body 1A. At the projection amount change section 43, the amount of protrusion decreases from the projection length H of the projection 40, which is the amount of protrusion at the protruding end face 41, down to 0.

[0039] Figure 6 shows the projection 40 and its vicinity on the guide roller 27B that constitutes the stretching portion 23. Figure 6 shows the state in which the projection 40 is pressing against the uncoated area 12 of the current collector 2. Also in Figure 6, the strip-shaped body 1A is shown in a cross-section perpendicular or substantially perpendicular to the longitudinal direction, and the guide roller 27B is shown in a cross-section parallel or substantially parallel to the rotation axis R. The projection 40 in this embodiment is formed in a multi-stage projection structure and comprises multiple stepped portions M. In the example shown in Figures 5 and 6, the projection 40 is provided with four stepped portions M1 to M4. In the following description, the case in which four stepped portions M1 to M4 are provided will be described, but the configuration of the projection 40 described below is also applicable when the number of stepped portions M provided on the projection 40 is two or three, or when the number of stepped portions M provided on the projection 40 is five or more.

[0040] Each of the stepped sections M1 to M4 is formed around the entire circumference of the guide roller 27B. The four stepped sections M1 to M4 are arranged in the order M1, M2, M3, and M4 from the inner circumference to the outer circumference of the guide roller 27B. Among the multiple stepped sections M1 to M4, the stepped section located closer to the outer circumference of the guide roller 27A has a larger protrusion. The protruding end face 41 of the projection 40 is formed by the outermost stepped section M4 of the stepped sections M1 to M4. Therefore, the protrusion amount of the outermost stepped section M4 is equal to the projection length H of the projection 40. Each of the stepped sections M2 to M4, except for the innermost stepped section M1, is adjacent to a stepped section one step further inward, on the opposite side of the axial direction of the guide roller 27A from the side where the projection side surface 42 is located. For example, stepped section M3 is adjacent to stepped section M4, on the opposite side of the axial direction of the guide roller 27A from the side where the projection side surface 42 is located. Furthermore, among the stepped sections M1 to M3, the stepped sections on the inner circumference are located further away from the outermost stepped section M4 in the axial direction of the guide roller 27A.

[0041] When the projection 40 is pressing against the uncoated area 12 of the current collector 2, each of the stepped sections M2 to M4 is adjacent to a stepped section one step further inward from the side where the active material-containing layer 3 is located in the width direction of the strip-shaped body 1A. When the projection 40 is pressing against the uncoated area 12 of the current collector 2, among the stepped sections M1 to M4, the stepped sections on the inner circumference are located closer to the active material-containing layer 3 (coated end 10) in the width direction of the strip-shaped body 1A (axial direction of the guide roller 27B). Therefore, among the stepped sections M1 to M4, stepped section M1 is located closest to the active material-containing layer 3 in the width direction of the strip-shaped body 1A, and stepped section M4 is located furthest from the active material-containing layer 3 in the width direction of the strip-shaped body 1A.

[0042] Each of the stepped sections M1 to M4 is provided with an extended surface (outer peripheral surface) 45 and a step-forming surface 46. In each of the stepped sections M1 to M4, the extended surface 45 and the step-forming surface 46 are formed around the entire circumference of the guide roller 27B in the circumferential direction. The extended surface 45 of each of the stepped sections M1 to M4 faces the outer peripheral side of the guide roller 27B. In the projection 40, the extended surface 45 of the outermost stepped section M4 becomes the protruding end surface 41. The extended surface 45 of each of the stepped sections M1 to M4 extends along the axial direction of the guide roller 27B.

[0043] Furthermore, in each of the stepped sections M1 to M4, the step-forming surface 46 faces the opposite side of the side where the projection side 42 is located, in the axial direction of the guide roller 27B. When the projection 40 is pressing against the uncoated area 12 of the current collector 2, the step-forming surfaces 46 of each of the stepped sections M1 to M4 face the side where the active material-containing layer 3 is located, in the width direction of the strip-shaped body 1A. In each of the stepped sections M1 to M4, the step-forming surface 46 extends along the radial direction of the guide roller 27B, and the outer peripheral end of the step-forming surface 46 is connected to the extended surface 45. In each of the stepped sections M2 to M4, except for the innermost stepped section M1, the inner peripheral end of the step-forming surface 46 is connected to the extended surface 45 of the stepped section one step further inward. Also, in stepped section M1, the inner peripheral end of the step-forming surface 46 is located at the base of the projection of the projection 40. Each of the stepped portions M2 to M4 forms a step h with respect to the stepped portion on the inner circumference side by the step-forming surface 46. Step portion M1 also forms a step h with respect to the base position of the projection 40 by the step-forming surface 46.

[0044] The step heights h formed by the multiple step portions M1 to M4 may be the same size relative to each other, or they may be different sizes relative to each other. However, it is preferable that the step height h formed by each of the multiple step portions M1 to M4 is greater than 1 times and 5 times or less the thickness ta of the rolled active material-containing layer 3.

[0045] In this embodiment, the step-forming surface 46 of the outermost step portion M4 and the other step portions M1 to M3 form a protrusion amount change portion 43. In the protrusion amount change portion 43, the protrusion amount changes at each step-forming surface 46 of the step portions M1 to M4 by an amount of change equal to the step h formed by that step-forming surface 46. Therefore, in the protrusion amount change portion 43, the protrusion amount on the outer surface of the guide roller 27B decreases in a stepped manner toward the side away from the protruding end face 41 and the projection side face 42 in the axial direction of the guide roller 27B. When the projection 40 is pressing against the uncoated area 12 of the current collector 2, the protrusion amount in the protrusion amount change portion 43 decreases in a stepped manner toward the side where the active material-containing layer 3 is located in the width direction of the strip-shaped body 1A. In other words, in the protrusion amount change section 43, at each of the step-forming surfaces 46 of the stepped sections M1 to M4, the amount of protrusion decreases toward the side where the active material-containing layer 3 is located in the width direction of the strip-shaped body 1A.

[0046] Furthermore, each of the stepped sections M1 to M4 is formed over a width dimension w in the axial direction of the guide roller 27B (the width direction of the strip-shaped body 1A when the strip-shaped body 1A is being conveyed). The width dimension w of the outermost stepped section M4 is the predetermined width dimension w0 of the protruding end face 41 described above. The width dimensions w of the multiple stepped sections M1 to M4 may be the same size as each other, or they may be different sizes. However, it is preferable that the width dimension w of each of the stepped sections M1 to M4 is greater than 0 mm and 15 mm or less, similar to the predetermined width dimension w0 of the protruding end face 41.

[0047] As described above, in this embodiment, the projection length H to the projection end of the projection 40 that presses against the uncoated region 12 of the current collector 2 is greater than the thickness ta of the active material-containing layer 3 rolled in the rolling section 21. Therefore, even if the strip-shaped body 1A has a large dimension b of the uncoated region 12 in the width direction of the current collector 2, the projection 40 presses against the uncoated region 12 of the current collector 2 against the strip-shaped body 1A to which tension is applied in the longitudinal direction, causing the uncoated region 12 to be appropriately stretched in the longitudinal direction. As a result, even if the strip-shaped body 1A has a large dimension b of the uncoated region 12 in the width direction of the current collector 2, such as a strip-shaped body 1A with a dimension b greater than 25 mm, the curvature of the strip-shaped body 1A caused by the rolling of the active material-containing layer 3 is appropriately corrected.

[0048] Furthermore, by setting the protrusion length H of the projection 40 to more than twice (200%) the thickness ta of the rolled active material-containing layer 3, the uncoated area 12 is further appropriately stretched in the longitudinal direction by the pressure from the projection 40. This further appropriately corrects the curvature of the strip-shaped body 1A caused by the rolling of the active material-containing layer 3. In addition, by setting the protrusion length H of the projection 40 to 15 times (1500%) or less the thickness ta of the rolled active material-containing layer 3, damage to the uncoated area 12 of the current collector 2 caused by the pressure from the projection 40 is effectively prevented.

[0049] Furthermore, in this embodiment, the projection 40 is provided with a protruding end face 41 and a protrusion amount changing portion 43, as described above. When the projection 40 is pressing against the uncoated area 12 of the current collector 2, the protrusion amount changing portion 43 is located between the protruding end face 41 and the active material-containing layer 3 in the width direction of the strip-shaped body 1A, and the amount of protrusion decreases in the protrusion amount changing portion 43 toward the side where the active material-containing layer 3 is located in the width direction of the strip-shaped body 1A. By pressing against the uncoated area 12 in the manner described above with the projection 40 provided with the protruding end face 41 and the protrusion amount changing portion 43, the uncoated area 12 is further appropriately stretched in the longitudinal direction. As a result, the curvature of the strip-shaped body 1A caused by the rolling of the active material-containing layer 3 is further appropriately corrected. In addition, in this embodiment, the uncoated area 12 is further appropriately stretched in the longitudinal direction 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.

[0050] Furthermore, in this embodiment, as described above, multiple stepped portions M1 to M4 are formed on the projection 40, and the outermost stepped portion M4 among the stepped portions M1 to M4 forms the protruding end face 41. Then, in the protrusion amount change portion 43 of the projection 40, the amount of protrusion decreases in a stepped manner toward the side away from the protruding end face 41 in the axial direction of the guide roller 27B due to the step difference formed by each of the multiple stepped portions M1 to M4. As described above, in this embodiment, by providing multiple stepped portions M1 to M4, the protrusion amount change portion 43 is appropriately formed on the projection 40 due to the step difference h in each of the stepped portions M1 to M4.

[0051] Furthermore, by making the step height h of each of the multiple steps M1 to M4 greater than 1x (100%) of the thickness ta of the rolled active material-containing layer 3, the uncoated area 12 is further appropriately stretched in the longitudinal direction by the pressure from the protrusions 40. This further appropriately corrects the curvature of the strip-shaped body 1A caused by the rolling of the active material-containing layer 3. In addition, by making the step height h of each of the multiple steps M1 to M4 less than 5x (500%) of the thickness ta of the rolled active material-containing layer 3, damage to the uncoated area 12 of the current collector 2 caused by the pressure from the protrusions 40 is effectively prevented. Furthermore, by making the width dimension w of each of the steps M1 to M4 in the axial direction of the guide roller 27B 15 mm or less, the uncoated area 12 is further appropriately stretched in the longitudinal direction.

[0052] In one modified example shown in Figure 7, multiple stepped portions M1 to M4 are formed on the projection 40. However, in this modified example, a curved surface (chamfered portion) 47 is formed between the extended surface (outer surface) 45 and the step-forming surface 46 in each of the stepped portions M1 to M4. In each of the stepped portions M1 to M4, the curved surface 47 is formed over the entire circumference in the circumferential direction (around the axis of rotation R) of the guide roller 27B. Figure 7 shows the projection 40 and its vicinity in the guide roller 27B that constitutes the stretched portion 23. Figure 7 also shows the state in which the projection 40 is pressing against the uncoated area 12 of the current collector 2. Furthermore, in Figure 7, the strip-shaped body 1A is shown in a cross-section perpendicular or approximately perpendicular to the longitudinal direction, and the guide roller 27B is shown in a cross-section parallel or approximately parallel to the axis of rotation R.

[0053] As shown in Figure 7, in a cross section parallel or approximately parallel to the rotation axis R, each curved surface 47 of the stepped sections M1 to M4 is arc-shaped or approximately arc-shaped. The center of the arc-shaped or approximately arc-shaped curved surface 47 of the stepped sections M1 to M4 is located on the side where the projection side surface 42 is located, and on the inner circumference side of the guide roller 27B. Furthermore, the radius of curvature r of each curved surface 47 of the stepped sections M1 to M4 is preferably 0.5 mm or more and 7 mm or less.

[0054] This modified version also produces the same functions and effects as the embodiments described above. That is, even if the strip-shaped body 1A has a large dimension b of the uncoated area 12 in the width direction of the current collector 2, the curvature of the strip-shaped body 1A caused by the rolling of the active material-containing layer 3 is appropriately corrected. Furthermore, in this modified version, by setting the radius of curvature r of each curved surface 47 of the stepped portions M1 to M4 to 7 mm or less, the uncoated area 12 is further appropriately stretched in the longitudinal direction by the pressure from the protrusions 40. As a result, the curvature of the strip-shaped body 1A caused by the rolling of the active material-containing layer 3 is further appropriately corrected. In addition, by setting the radius of curvature r of each curved surface of the multiple stepped portions M1 to M4 to 0.5 mm or more, damage to the uncoated area 12 of the current collector 2 caused by the pressure from the protrusions 40 is effectively prevented.

[0055] In another modified example shown in Figure 8, the projection 40 is not formed as a multi-stage projection structure, but as a single-stage projection structure. Here, Figure 8 shows the projection 40 and its vicinity on the guide roller 27B that constitutes the stretched portion 23. Figure 8 also shows the state in which the projection 40 is pressing against the uncoated area 12 of the current collector 2. Furthermore, in Figure 8, the strip-shaped body 1A is shown in a cross-section perpendicular or approximately perpendicular to the longitudinal direction, and the guide roller 27B is shown in a cross-section parallel or approximately parallel to the rotation axis R.

[0056] As shown in Figure 8, etc., in this modified example as well, the projection length H of the projection 40 to the projection end (projection end face 41) is greater than the thickness ta of the active material-containing layer 3 rolled by the rolling section 21. Furthermore, it is preferable that the projection length H of the projection 40 is 2 times or more and 15 times or less the thickness ta of the active material-containing layer 3. In this modified example as well, similar to the embodiment described above, the projection end face 41 and the projection amount change section 43 are formed on the projection 40. The projection end face 41 is formed over a predetermined width dimension w0 in the axial direction of the guide roller 27B, and it is preferable that the predetermined width dimension w0 of the projection end face 41 is greater than 0 mm and 15 mm or less.

[0057] However, in this modified example, the projection amount change section 43 of the projection 40 is formed by an inclined surface 51. The inclined surface 51 is formed around the entire circumference of the guide roller 27B in the circumferential direction. The inclined surface 51 is also inclined with respect to both the axial direction and the radial direction of the guide roller 27B. In the projection amount change section 43, the amount of projection on the outer circumferential surface of the guide roller 27B decreases in a slope-like manner toward the side away from the projection end face 41 and projection side face 42 in the axial direction of the guide roller 27B. When the projection 40 is pressing against the uncoated area 12 of the current collector 2, the amount of projection in the projection amount change section 43 decreases in a slope-like manner toward the side where the active material containing layer 3 is located in the width direction of the strip-shaped body 1A. In this modified example as well, in the projection amount change section 43, the amount of projection decreases from the projection length H of the projection 40, which is the amount of projection at the projection end face 41, down to 0.

[0058] Furthermore, in one modified example, the projection amount change portion 43 formed by the stepped portions M1 to M4 or the inclined surface 51 is not formed on the projection 40. In this modified example as well, the projection length H of the projection 40 to the projection end (projection end face 41) is greater than the thickness ta of the active material-containing layer 3 rolled by the rolling portion 21. It is also preferable that the projection length H of the projection 40 is 2 times or more and 15 times or less the thickness ta of the active material-containing layer 3. In addition, it is preferable that the projection 40 has a projection end face 41 formed over a predetermined width dimension w0 in the axial direction of the guide roller 27B, and that the predetermined width dimension w0 of the projection end face 41 is greater than 0 mm and 15 mm or less.

[0059] In all of the modifications described above, the projection length H of the projection 40 to the projection end (projection end face 41) is greater than the thickness ta of the active material-containing layer 3 rolled by the rolling section 21. For this reason, all of the modifications produce the same effects and benefits as the embodiments described above. That is, even if the strip-shaped body 1A has a large dimension b of the uncoated region 12 in the width direction of the current collector 2, the curvature of the strip-shaped body 1A caused by the rolling of the active material-containing layer 3 is appropriately corrected.

[0060] (Verification related to the embodiment, etc.) Furthermore, verifications related to the above-described embodiment were performed. The verifications performed are described below. In the verification, an active material-containing layer was coated onto the surface of a current collector to form a strip. Aluminum foil was used as the current collector. For coating the surface of the current collector, a slurry was prepared by suspending the active material, conductive agent, and binder in an organic solvent. The active material was LiNi with an average primary particle size of 2 μm. 0.5 Co 0.2 Mn 0.3 O2 composite oxide was used, with graphite powder as the conductive agent and polyvinylidene fluoride (PVdF) as the binder. N-methyl-2-pyrrolidone (NMP) solvent was used as the organic solvent. For the slurry preparation, the active material was mixed in a ratio of 90% by mass, the conductive agent in a ratio of 5% by mass, and the binder in a ratio of 5% by mass. The prepared slurry was then coated onto the surface of the current collector. At this time, the slurry was not coated on one of the pair of long edges of the current collector and its vicinity. As a result, in the strip-shaped material, a coated region was formed where the active material-containing layer was coated on both of the pair of main surfaces, and an uncoated region was formed where the active material-containing layer was not coated on either of the pair of main surfaces. The uncoated region was formed on one of the pair of long edges of the current collector and its vicinity.

[0061] In the verification, after forming a strip-shaped body as described above, the active material-containing layer (slurry) coated on the surface of the current collector was dried. Then, the strip-shaped body was conveyed in a conveying section similar to the example in Figure 3, as described above in the embodiments. Then, in a rolling section similar to the example in Figure 3, the active material-containing layer on the conveyed strip-shaped body was rolled by a roll press. Furthermore, downstream of the rolling section, the strip-shaped body was pulled downstream by a tensioning section similar to the example in Figure 3. This applied longitudinal tension to the strip-shaped body between the tensioning section and the rolling section. In the verification, a protrusion was provided on the outer circumferential surface of a roller corresponding to the guide roller 27B in the example in Figure 3. The protrusion and the roller on which the protrusion is formed were made of stainless steel. Then, as described above in the embodiments, the uncoated area of ​​the current collector was pressed against the tensioned strip-shaped body by the protrusion, stretching the uncoated area in the longitudinal direction.

[0062] In the verification, after stretching the unpainted area with a protrusion, the curvature η of the strip-shaped body was measured using the measurement method shown in the example in Figure 4. At this time, assuming the aforementioned specified distance D was 1000 mm, two points P1 and P2 were identified on the long edge opposite the unpainted area of ​​the current collector where the straight-line distance was the specified distance D.

[0063] In the verification, the aforementioned process, including stretching of the uncoated area by the protrusions, was performed under the conditions of Examples 1 to 7 and Comparative Example 1, as described below, and the amount of curvature η of the strip was measured. In Examples 1 to 7 and Comparative Example 1, the pressure (pressing pressure) applied to the active material-containing layer in the rolling section and the tensile force applied to the strip downstream in the tensioning section were kept the same for all of them. Figure 9 shows the conditions and measurement results of the amount of curvature η for Examples 1 to 7 and Comparative Example 1 in the verification related to the embodiments, etc.

[0064] As shown in Figure 9, etc., in Examples 1 to 7, a protrusion was formed on a multi-stage protruding structure having multiple steps, similar to the examples in Figures 5 and 6. In Example 1, the protrusion length H of the protrusion to the protruding end (protruding end face) was set to 2.4 times the thickness ta of the rolled active material-containing layer. The number of steps in the protrusion was set to two, and the width dimension w of each step was set to 15 mm. Therefore, the predetermined width dimension w0 of the protruding end face corresponding to the width dimension w of the outermost step became 15 mm. In addition, the step difference h at each step was set to 1.2 times the thickness ta of the rolled active material-containing layer. In the strip-shaped body, the dimension of the uncoated area in the width direction of the strip-shaped body was set to 30 mm.

[0065] In Example 2, the protruding length H was set to 6 times the thickness ta, the number of steps to 5, the width dimension w to 6 mm, the step height h to 1.2 times the thickness ta, and the dimension b to 30 mm. In Example 3, the protruding length H was set to 10.8 times the thickness ta, the number of steps to 9, the width dimension w to 3 mm, the step height h to 1.2 times the thickness ta, and the dimension b to 30 mm. In Example 4, the protruding length H was set to 10 times the thickness ta, the number of steps to 5, the width dimension w to 6 mm, the step height h to 2 times the thickness ta, and the dimension b to 30 mm. In Example 5, the protruding length H was set to 14.4 times the thickness ta, the number of steps to 12, the width dimension w to 2.5 mm, the step height h to 1.2 times the thickness ta, and the dimension b to 30 mm. In Example 6, the protruding length H was set to 15 times the thickness ta, the number of steps was set to 3, the width dimension w was set to 10 mm, the step height h was set to 5 times the thickness ta, and the dimension b was set to 30 mm. In Example 7, the protruding length H was set to 15 times the thickness ta, the number of steps was set to 10, the width dimension w was set to 6 mm, the step height h was set to 1.5 times the thickness ta, and the dimension b was set to 60 mm.

[0066] In Comparative Example 1, a protrusion was formed on a single-stage protruding structure. Therefore, the number of stages was one. Furthermore, the configuration corresponding to the protrusion amount change section 43 of the previously described embodiment was not formed on the protrusion. In addition, the protrusion length H of the protrusion to the protruding end (protruding end face) was set to 1 times the thickness ta of the rolled active material-containing layer. In Comparative Example 1, since there is only one stage, the step height h of the stage became 1 times the thickness ta because the protrusion length H is 1 times the thickness ta. Also, the width dimension w of the stage was set to 30 mm. In Comparative Example 1, since the width dimension w of the stage corresponds to the predetermined width dimension w0 of the protruding end face, setting the width dimension w to 30 mm resulted in the predetermined width dimension w0 of the protruding end face being 30 mm. In addition, in the strip-shaped body, the dimension b of the uncoated area in the width direction of the strip-shaped body was set to 30 mm.

[0067] The amount of curvature η of the strip after the uncoated region was stretched longitudinally by the protrusions was 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 each of Examples 1 to 7, the amount of curvature η was smaller than that of Comparative Example 1. Therefore, it was demonstrated that by making the protrusion length H of the protrusions larger than the thickness ta of the rolled active material-containing layer 3, compared to the case where the protrusion length H is 1 or less than the thickness ta of the rolled active material-containing layer 3, the curvature of the strip generated by rolling the active material-containing layer is appropriately corrected.

[0068] According to at least one of these embodiments or examples, longitudinal tension is applied to the strip between a rolling section that rolls the active material-containing layer and a tensioning section that stretches the strip. Then, the uncoated area of ​​the current collector is pressed by a projection that protrudes outward on the outer circumference of the roller between the rolling section and the tensioning section, thereby stretching the uncoated area in the longitudinal direction. The projection length of the projection to its end is greater than the thickness of the rolled active material-containing layer. This makes it possible to provide a method and apparatus for manufacturing an electrode structure that can appropriately correct the curvature of the strip caused by rolling the active material-containing layer, even if the dimensions of the uncoated area in the width direction of the current collector become large.

[0069] The following are additional notes. [1] A strip-shaped body having an active material-containing layer coated on the surface of the current collector, and having an uncoated area formed on one of a pair of long edges along the longitudinal direction of the current collector and in its vicinity where the active material-containing layer is not coated, In the conveyed strip, the active material-containing layer is rolled, Downstream from the rolling section that rolls the active material-containing layer, the strip is pulled downstream, thereby applying longitudinal tension to the strip between the pulling section and the rolling section. The uncoated region of the current collector is stretched in the longitudinal direction by pressing the uncoated region of the strip-shaped body against the tensioned strip-shaped body with a projection that protrudes outward from the outer circumference of the roller between the rolling portion and the tensioning portion, wherein the uncoated region is pressed by a projection whose protruding length to the protruding end is greater than the thickness of the active material-containing layer rolled in the rolling portion. A method for manufacturing an electrode structure comprising the above. [2] The strip-shaped body is transported with the rotation axis of the roller aligned with the width direction of the strip-shaped body. In the aforementioned projection, the protruding end surface that forms the protruding end is formed over a predetermined width dimension in the axial direction along the rotation axis of the roller, In the aforementioned projection, a portion of the projection that changes in the amount of protrusion is formed adjacent to the protruding end face from one side in the axial direction of the roller, such that the amount of protrusion decreases toward the side away from the protruding end face. When the projection is pressing against the uncoated area of ​​the current collector, the protrusion amount change portion is located between the protruding end face of the projection and the active material-containing layer in the width direction of the strip-shaped body, and the amount of protrusion at the protrusion amount change portion decreases toward the side where the active material-containing layer is located in the width direction of the strip-shaped body. [1] A method for manufacturing [1]. [3] The projection has multiple stepped portions formed on it such that the amount of protrusion increases with respect to the stepped portion located on the outer circumference side of the roller. In the projection, the outermost step among the plurality of steps forms the protruding end face. The amount of protrusion at the portion where the amount of protrusion changes decreases in a stepped manner toward the side away from the protruding end face in the axial direction of the roller, due to the step difference formed by each of the plurality of stepped portions. [2] A method for manufacturing [2]. [4] The manufacturing method of [3] wherein the step difference in each of the plurality of steps in the projection is greater than 1 and less than or equal to 5 times the thickness of the rolled active material-containing layer. [5] The manufacturing method according to any one of [2] to [4], wherein the predetermined width dimension of the protruding end face of the projection is greater than 0 mm and 15 mm or less. [6] The manufacturing method according to any one of [1] to [5], wherein the projection length to the protruding end is 2 times or more and 15 times or less the thickness of the rolled active material-containing layer. [7] A manufacturing method according to any one of [1] to [6], wherein the active material-containing layer is applied to the surface of the current collector such that the dimensions of the uncoated area in the width direction of the strip are greater than 25 mm. [8] A method for manufacturing any one of [1] to [7], further comprising forming the current collector from aluminum, an aluminum alloy, copper, zinc, stainless steel, and titanium. [9] A conveying unit for conveying a strip-shaped body having an active material-containing layer coated on the surface of a current collector, and having an uncoated area formed on one of a pair of long edges along the longitudinal direction of the current collector and in its vicinity where the active material-containing layer is not coated, The conveying section includes a rolling section for rolling the active material-containing layer in the strip-shaped body being conveyed, A tensioning section is provided downstream of the rolling section, which applies tension to the strip in the longitudinal direction between itself and the rolling section by pulling the strip downstream, A roller, and a stretching portion provided between the rolling portion and the tensioning portion, the stretching portion having a projection that protrudes outward from the outer circumference of the roller, wherein the projection presses against the uncoated region of the current collector against the strip-shaped body to which tension is applied, thereby stretching the uncoated region in the longitudinal direction, and the protruding length of the projection to the protruding end is greater than the thickness of the active material-containing layer rolled in the rolling portion, A manufacturing apparatus for electrode structures, comprising the following:

[0070] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0071] 1...Electrode structure, 1A...Strip-shaped body, 2...Current collector, 3...Active material-containing layer, 5,6...Main surface, 7...Long edge (first long edge), 8...Long edge (second long edge), 10...Coated end, 11...Coated area, 12...Uncoated area, 15...Manufacturing equipment, 16...Conveying section, 21...Rolling section, 22...Tensioning section, 23...Stretching section, 25...Winding section, 27A~27C...Guide roller, 40...Protrusion, 41...Protruding end face, 43...Protrusion amount change section, M1~M4...Step section, H...Protrusion length, h...Step difference, w0...Determined width dimension, w...Width dimension, b...Dimension, η...Curve amount.

Claims

1. A strip-shaped body is transported in which an active material-containing layer is coated on the surface of the current collector, and an uncoated region is formed on one of a pair of long edges along the longitudinal direction of the current collector and in its vicinity, where the active material-containing layer is not coated. In the conveyed strip, the active material-containing layer is rolled, Downstream from the rolling section that rolls the active material-containing layer, the strip is pulled downstream, thereby applying longitudinal tension to the strip between the pulling section and the rolling section. The uncoated region of the current collector is stretched in the longitudinal direction by pressing the uncoated region of the strip-shaped body against the tensioned strip-shaped body with a projection that protrudes outward from the outer circumference of the roller between the rolling portion and the tensioning portion, wherein the uncoated region is pressed by a projection whose protruding length to the protruding end is greater than the thickness of the active material-containing layer rolled in the rolling portion. It is equipped with, The strip-shaped body is conveyed with the rotation axis of the roller aligned with the width direction of the strip-shaped body. In the aforementioned projection, the protruding end surface that forms the protruding end is formed over a predetermined width dimension in the axial direction along the rotation axis of the roller, In the aforementioned projection, a portion of the projection that changes in the amount of protrusion is formed adjacent to the protruding end face from one side in the axial direction of the roller, such that the amount of protrusion decreases toward the side away from the protruding end face. When the projection is pressing against the uncoated area of ​​the current collector, the protrusion amount change portion is located between the protruding end face of the projection and the active material-containing layer in the width direction of the strip-shaped body, and the amount of protrusion at the protrusion amount change portion decreases toward the side where the active material-containing layer is located in the width direction of the strip-shaped body. The projection has multiple stepped portions formed on it such that the amount of protrusion increases with the stepped portion located on the outer circumference side of the roller. In the projection, the outermost step among the plurality of steps forms the protruding end face. The amount of protrusion at the portion where the amount of protrusion changes decreases in a stepped manner toward the side away from the protruding end face in the axial direction of the roller, due to the step difference formed by each of the plurality of stepped portions. When the projection is pressing against the uncoated area of ​​the current collector, the entire portion of the protrusion change formed by the steps other than the outermost step among the plurality of steps is located on the side of the strip-shaped body in the width direction relative to the active material-containing layer where the uncoated area is located. A method for manufacturing an electrode structure.

2. The manufacturing method according to claim 1, wherein the step difference in each of the plurality of steps in the projection is greater than 1 and less than or equal to 5 times the thickness of the rolled active material-containing layer.

3. The manufacturing method according to claim 1, wherein the predetermined width dimension of the protruding end face of the projection is greater than 0 mm and 15 mm or less.

4. The manufacturing method according to any one of claims 1 to 3, wherein the projection length to the projection end is 2 times or more and 15 times or less the thickness of the rolled active material-containing layer.

5. The manufacturing method according to any one of claims 1 to 3, wherein, in coating the surface of the current collector with the active material-containing layer, the active material-containing layer is coated onto the current collector such that the dimensions of the uncoated area in the width direction of the strip-shaped body are greater than 25 mm.

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

7. A conveying unit for conveying a strip-shaped body in which an active material-containing layer is coated on the surface of a current collector, and an uncoated region is formed on one of a pair of long edges along the longitudinal direction of the current collector and in its vicinity, where the active material-containing layer is not coated. The conveying section includes a rolling section for rolling the active material-containing layer in the strip-shaped body being conveyed, A tensioning section is provided downstream of the rolling section, which applies tension to the strip in the longitudinal direction between itself and the rolling section by pulling the strip downstream, A roller, and a stretching portion provided between the rolling portion and the tensioning portion, the stretching portion having a projection that protrudes outward from the outer circumference of the roller, wherein the projection presses against the uncoated region of the current collector against the strip-shaped body to which tension is applied, thereby stretching the uncoated region in the longitudinal direction, and the protruding length of the projection to the protruding end is greater than the thickness of the active material-containing layer rolled in the rolling portion, It is equipped with, The conveying unit conveys the strip-shaped body with the rotation axis of the roller of the stretching unit aligned with the width direction of the strip-shaped body. In the projection of the stretched portion, the protruding end surface that becomes the protruding end is formed over a predetermined width dimension in the axial direction along the rotation axis of the roller, In the aforementioned projection, a portion of the projection that changes in the amount of protrusion is formed adjacent to the protruding end face from one side in the axial direction of the roller, such that the amount of protrusion decreases toward the side away from the protruding end face. When the projection is pressing against the uncoated area of ​​the current collector, the protrusion amount change portion is located between the protruding end face of the projection and the active material-containing layer in the width direction of the strip-shaped body, and the amount of protrusion at the protrusion amount change portion decreases toward the side where the active material-containing layer is located in the width direction of the strip-shaped body. The projection has multiple stepped portions formed on it such that the amount of protrusion increases with the stepped portion located on the outer circumference side of the roller. In the projection, the outermost step among the plurality of steps forms the protruding end face. The amount of protrusion at the portion where the amount of protrusion changes decreases in a stepped manner toward the side away from the protruding end face in the axial direction of the roller, due to the step difference formed by each of the plurality of stepped portions. When the projection is pressing against the uncoated area of ​​the current collector, the entire portion of the protrusion change formed by the steps other than the outermost step among the plurality of steps is located on the side of the strip-shaped body in the width direction relative to the active material-containing layer where the uncoated area is located. Manufacturing equipment for electrode structures.

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