Method for manufacturing electrodes for secondary batteries and electrodes for secondary batteries

Abstract

This invention provides a method for manufacturing electrodes for secondary batteries that can efficiently produce electrodes. [Solution] The method includes an extrusion die 30 comprising a rotating body 31 that rotates around an axis X, a stationary body 34 having a housing portion 33 that communicates with an opening 32 provided in the axial direction and is capable of housing the rotating body 31, and an annular extrusion port 35 formed between the rotating body 31 and the inner surface of the housing portion 33 in an axial direction, and a powdered composite film material 10 containing a binder resin that is finely fibrousized, and an extrusion process in which the composite film material 10 is supplied to the extrusion die 30 while the rotating body 31 is rotating and discharged from the extrusion port 35 to form a cylindrical body 41 in which the binder resin has been finely fibrousized, a film forming process in which the cylindrical body 41 formed in the extrusion process is rolled sequentially from one axial side of the cylindrical body 41 formed in the extrusion process to form a composite film, and an adhesion process in which the composite film formed in the film forming process is adhered to a current collector foil.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an electrode for a secondary battery and an electrode for a secondary battery.

Background Art

[0002] In recent years, batteries such as lithium-ion secondary batteries have been suitably used as power sources for driving vehicles such as battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). In this type of battery, an electrode for a secondary battery is used. A manufacturing method related to such an electrode is disclosed in, for example, Patent Document 1 below.

[0003] Patent Document 1 discloses a manufacturing method by a dry process in which a slurry is not coated on a current collector foil as a manufacturing method of a composite film (referred to as a "dry electrode film" in the document) included in an electrode for a secondary battery. Specifically, it is a method of manufacturing a composite film by rolling a mixed powder containing an active material, a conductive material, and a binder resin using a calender roll without using a solvent.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Figure 10 is a schematic diagram illustrating the manufacturing process of a conventional asphalt film. Referring to this, the mixed powder 50 is compressed into a sheet-like shape by passing through a calender roll 60 having a pair of calender rollers 60a, 60a to produce the asphalt film 70. The calender roll 60 has a pair of partition members 61 installed on both sides of the mixed powder 50, and the width dimension of the asphalt film 70 is set by the pair of partition members 61. Here, the mixed powder 50 contains a binder resin 51 such as polytetrafluoroethylene (PTFE). When forming the asphalt film 70 using the binder resin 51 in this way, the mixed powder 50 containing the binder resin 51 is stretched by the calender roll 60. At this time, in the asphalt film 70 produced, the fibrous binder resin 51 is oriented in the longitudinal direction L, and the binder resin 51 is hardly oriented in the width direction W of the asphalt film 70 which is perpendicular to the longitudinal direction L. Therefore, the strength of the composite film 70 was significantly weaker in the width direction W compared to the length direction L.

[0006] Furthermore, these composite film 70s posed challenges in terms of secondary battery productivity, such as the risk of cracking during film formation, or the risk of rupture if tension is applied to the composite film 70 during transport, making efficient transport of the composite film 70 difficult. To increase the strength of the composite film 70 in the W direction, measures such as adding more binder resin 51 can be considered. However, in this case, there were also challenges such as a decrease in battery capacity due to a relative decrease in the amount of active material in the composite film 70, and a deterioration in resistance due to an increase in the amount of binder resin 51 in the composite film 70. Therefore, there was room for improvement in the manufacturing of electrodes for secondary batteries.

[0007] This invention has been made in view of the above circumstances, and its purpose is to provide a method for manufacturing electrodes for secondary batteries that can efficiently produce electrodes. [Means for solving the problem]

[0008] The characteristic configuration of the method for manufacturing electrodes for secondary batteries according to the present invention, which achieves the above objective, is as follows: A method for manufacturing a strip-shaped electrode for a secondary battery, comprising a current collector foil and a composite material film adhered to the current collector foil, An extrusion die comprising a rotating body that rotates around an axis, and a stationary body having a housing portion that communicates with an opening provided in the axial direction and is capable of housing the rotating body, wherein an annular extrusion opening is formed between the rotating body and the inner surface of the housing portion, when viewed in the axial direction, Using a powdered composite film material containing at least an active material, a conductive material, and a binder resin that forms fine fibers, An extrusion molding process in which the composite film material is supplied to the extrusion die while the rotating body is rotating and discharged from the extrusion port to form a cylindrical body in which the binder resin has been finely fibroused, A film forming step is performed in which the cylindrical body formed in the extrusion molding step is rolled sequentially from one axial side to form a composite film, The feature is that it includes an bonding step of bonding the composite film formed in the film-forming step to the current collector foil.

[0009] According to the above characteristic configuration, when forming a cylindrical body, rotating the rotating body applies a force along the direction of rotation of the rotating body to the composite film material flowing down from between the rotating body and the housing of the stationary body toward the extrusion port. As a result, a portion of the binder resin in the cylindrical body becomes fine fibers that extend along the circumferential direction. Then, by rolling the cylindrical body sequentially from one side in the axial direction, a portion of the binder resin becomes fine fibers that extend along the longitudinal direction of the composite film. In other words, the composite film contains both fine fibers that extend along the width direction and fine fibers that extend along the longitudinal direction. As a result, the ratio of tensile strength in the width direction to tensile strength in the longitudinal direction is larger compared to conventional methods. Therefore, when manufacturing electrodes, problems such as breakage during transport due to insufficient strength of the composite film and inability to increase the transport speed are less likely to occur, and electrodes can be manufactured efficiently.

[0010] Further characteristic features of the method for manufacturing electrodes for secondary batteries according to the present invention are: Between the extrusion molding step and the film formation step, there is a pre-film formation step in which the cylindrical body is rolled sequentially from one side in the axial direction to form a strip-shaped body. The film formation step involves rolling the strip-shaped body formed in the preliminary film formation step sequentially from one side in the longitudinal direction to form an composite film.

[0011] According to the above characteristic configuration, a strip-shaped body is formed from a tubular body through a preliminary film formation process, and by rolling the strip-shaped body, thickness variations in the composite film can be suppressed.

[0012] Further characteristic features of the method for manufacturing electrodes for secondary batteries according to the present invention are: The extrusion die is The rotating body has a tapered portion that gradually decreases in diameter in the axial direction from the extrusion opening toward the opposite side, In the aforementioned fixed body, the inner surface of the housing portion facing the tapered portion of the rotating body is parallel to the outer surface of the tapered portion.

[0013] According to the above-described configuration, the asphalt film material flows down along the outer surface of the tapered portion of the rotating body between the tapered portion and the inner wall surface of the housing portion, making it easy to maintain a constant extrusion speed of the asphalt film material from the extrusion port. Therefore, unevenness in the thickness of the asphalt film is less likely to occur. In addition, by changing the relative position of the rotating body and the stationary body in the axial direction, the cross-sectional area of ​​the flow path of the asphalt film material and the opening area of ​​the extrusion port can be changed. Therefore, the conditions for extrusion molding can be easily adjusted.

[0014] The characteristic configuration of the electrode for secondary batteries according to the present invention is: The key feature is that it is manufactured using the method for manufacturing electrodes for secondary batteries described above.

[0015] According to the above-described characteristic configuration, the ratio of tensile strength in the width direction to tensile strength in the longitudinal direction of the composite film is larger compared to conventional designs. Therefore, problems such as breakage during transport due to insufficient strength of the composite film and inability to increase transport speed are less likely to occur, making it possible to efficiently realize secondary battery electrodes with high tensile strength in the width direction.

[0016] The characteristic configuration of the electrode for secondary batteries according to the present invention is: It is a long member comprising a current collector foil and a composite material film bonded to the current collector foil. The composite film has a two-layer structure, and the two layers are continuous on one side in the width direction and discontinuous on the other side in the width direction.

[0017] In a secondary battery, the power generation efficiency is increased as the electrolyte is more easily retained in the composite film. For example, when the electrode includes a two-layer composite film, the electrolyte may flow out from both sides in the width direction between the two layers of the composite film. Therefore, it is preferable to take measures to increase the power generation efficiency of the secondary battery. In the electrode for a secondary battery according to the present invention, due to this characteristic configuration, the electrolyte that has penetrated between the two layers constituting the composite film flows out only from the other side in the width direction. Therefore, the electrolyte is easily retained in the composite film of the electrode for a secondary battery. As a result, the power generation efficiency of the secondary battery using the electrode for a secondary battery can be increased.

Effects of the Invention

[0018] As described above, according to the method for manufacturing an electrode for a secondary battery according to the present invention, the electrode can be efficiently manufactured.

Brief Description of the Drawings

[0019] [Figure 1] It is a diagram showing the order of the manufacturing process of the electrode for a secondary battery of the first embodiment. [Figure 2] It is a diagram showing an extrusion molding process. [Figure 3] It is a diagram showing a preliminary film-forming process. [Figure 4] It is a diagram showing a film-forming process. [Figure 5] It is a diagram showing an adhesion process. [Figure 6] It is a diagram showing an electrode for a secondary battery manufactured by the manufacturing method of the first embodiment. [Figure 7] It is a diagram showing an electrode for a secondary battery of another form. [Figure 8] It is a diagram showing the order of the manufacturing process of the electrode for a secondary battery of the second embodiment. [Figure 9] It is a diagram showing a film-forming process in the second embodiment. [Figure 10] This diagram shows a conventional method for manufacturing electrodes for secondary batteries. [Modes for carrying out the invention]

[0020] The method for manufacturing electrodes for secondary batteries according to this embodiment will be described below with reference to the drawings. Note that, in order to clarify the explanation, the descriptions and drawings have been simplified as appropriate.

[0021] [First Embodiment] A method for manufacturing the secondary battery electrode 1 and a first embodiment of the secondary battery electrode 1 will be described based on Figures 1 to 6. The secondary battery using the secondary battery electrode 1 of this embodiment is installed in an electric vehicle or a hybrid vehicle and supplies power to an electric motor, etc.

[0022] As shown in Figure 1, the manufacturing method for the secondary battery electrode 1 (see Figure 6) includes an extrusion molding step, a pre-film formation step, a film formation step, and an adhesive step. As shown in Figure 6, the secondary battery electrode 1 is strip-shaped and includes a current collector foil 5 and a composite film 43 bonded to the current collector foil 5.

[0023] In the manufacturing method of the electrode 1 for secondary batteries, a composite material film 43 is formed by an extrusion molding process, a pre-film formation process, and a film formation process, and the composite material film 43 is bonded to the current collector foil 5 in an bonding process.

[0024] The powdered composite film material 10 (see Figure 2), which is the raw material for the composite film, will be described below. The composite film material 10 contains at least an electrode active material, a conductive material, and a binder resin 11 that forms fine fibers.

[0025] The composite film material 10 can be manufactured by the following method. First, a mixture of electrode active material, conductive material, and binder resin 11 (see Figure 3) is prepared. The mixing for manufacturing the mixture is carried out so that the electrode active material, conductive material, and binder resin 11 are uniformly distributed. However, in this invention, since electrodes are manufactured by a dry process that does not use solvents, the mixing is carried out by dry mixing, and the materials are put into a normal mixing device such as a mixer or blender.

[0026] As the electrode active material, various known compounds that can be used for both the positive and negative electrodes can be used. Furthermore, as the conductive material, various known compounds can be used as long as they have little impact on changes in battery performance, such as electrode degradation, and are conductive.

[0027] The binder resin 11 is not limited to any particular material as long as it can be fibrousized. Microfibrillation of the binder resin 11 is performed in the process of preparing the mixture or in the extrusion molding process. Microfibrillation means that the polymer is divided into fine fibers. For example, this is done using mechanical shear force, and the surface of the fibrous polymer fibers dissolves, generating a large number of fine fibers. As such a binder resin 11, polytetrafluoroethylene (PTFE) or polyolefin may be used individually or as a mixture.

[0028] In this embodiment, the asphalt film material 10 is mixed by a mixing device 20 shown in Figure 2. The mixing of the asphalt film material 10 is performed using the mixing device 20 to ensure uniformity of the powder after mixing. The mixing device 20 has a housing 21, a material supply unit 22 for supplying the asphalt film material 10 into the housing 21 from the outside, and a screw conveyor 23 that kneads and extrudes the asphalt film material 10 inside the housing 21. The screw conveyor 23 is located in a kneading chamber 24 formed in the housing 21. The kneading chamber 24 is formed along the axis of the screw conveyor 23, with its upper part communicating with the material supply unit 22 and its downstream side in the axial direction of the screw conveyor 23 communicating with the material flow path 33b of the extrusion die 30, which will be described later. Inside the housing 21, the area around the kneading chamber 24 is filled with a liquid for temperature control.

[0029] The extrusion molding process will be explained based on Figure 2. The composite film material 10, mixed by the mixing device 20 shown in Figure 2, is supplied to the extrusion die 30. Figure 2 is a schematic diagram illustrating the formation of a cylindrical primary molded product (cylindrical body 41) by the extrusion die 30.

[0030] In the extrusion molding process, an extrusion die 30 and composite film material 10 supplied to the extrusion die 30 from a mixing device 20 are used. The extrusion die 30 is composed of a rotating body 31 that rotates around an axis X and a stationary body 34 that communicates with an opening 32 provided in the axial direction and has a housing portion 33 capable of accommodating the rotating body 31. The extrusion die 30 also has an annular extrusion port 35 formed between the rotating body 31 and the inner surface of the housing portion 33, which is viewed in the axial direction. In the extrusion molding process, the composite film material 10 is supplied to the extrusion die 30 while the rotating body 31 is rotating and discharged from the extrusion port 35 to form a cylindrical body 41 in which the binder resin 11 has been made into fine fibers.

[0031] The extrusion die 30 has a rotating body 31 with a tapered section 36 that gradually decreases in diameter from the extrusion opening 35 toward the opposite side in the axial X direction. Specifically, in this embodiment, the rotating body 31 has a cylindrical section 37 connected to the smaller diameter side (opposite side from the extrusion opening 35) of the tapered section 36. A drive source, such as a motor (not shown), is connected to the end of this cylindrical section 37, and this drive source rotates the rotating body 31 at a predetermined peripheral speed during extrusion molding. In the stationary body 34, the inner surface 34a of the housing section 33 facing the tapered section 36 of the rotating body 31 is parallel to the outer surface 36a of the tapered section 36. The gap between the inner surface 34a of the stationary body 34 of the extrusion die 30 and the outer surface 36a of the rotating body 31 is set to, for example, 0.2 to 2.0 mm. The peripheral speed of the rotating body 31 is set to, for example, 0.2 to 5.0 m / min. However, the above-mentioned gap and peripheral speed are not limited to this range, as they are related to the extrusion speed of the composite film material 10 and the composition of the composite film material 10.

[0032] In the extrusion molding process, the composite film material 10 mixed from the mixing device 20 is supplied to a material flow path 33b located between the cylindrical portion 37 of the rotating body 31 and the inner surface of the housing portion 33. The material flows down the material flow path 33b and is supplied between the tapered portion 36 of the rotating body 31 and the inner surface 34a of the stationary body 34. The supplied composite film material 10 flows down along the outer surface 36a of the tapered portion 36. Therefore, if the inner surface 34a of the housing portion 33 facing the tapered portion 36 of the rotating body 31 is parallel to the outer surface 36a of the tapered portion 36, it is easier to maintain a constant extrusion speed of the composite film material 10 from the extrusion port 35. Thus, unevenness in film thickness in the cylindrical body 41 is less likely to occur. Furthermore, by changing the relative position of the rotating body 31 and the stationary body 34 in the axial X direction, the cross-sectional area of ​​the material flow path 33b through which the composite film material 10 flows and the opening area of ​​the extrusion port 35 can be changed. Thus, the conditions for extrusion molding can be easily adjusted.

[0033] [Pre-deposition process] Figure 3 is a schematic diagram of the pre-film formation process. In the pre-film formation process, the cylindrical body 41 formed by the extrusion molding process is rolled sequentially from one side in the axial direction (longitudinal direction L) to form a strip. Specifically, in the pre-film formation process, the cylindrical body 41 extruded by the extrusion die 30 is rolled and a film is formed using a calender roll 62 which has a pair of calender rollers 62a, 62a. As a result, the cylindrical body 41 (asphalt film) is rolled in the longitudinal direction L and the width direction W to become a strip (pre-asphalt film) 42. In the strip 42, the cylindrical body 41 is flattened, and in addition, the binder resin 11 is diffused in the width direction W.

[0034] [Film formation process] Figure 4 is a schematic diagram illustrating the film deposition process. The film formation process involves further rolling the strip-shaped body 42 formed in the preliminary film formation process using a calender roll 63 having a pair of calender rollers 63a, 63a to form a film. By feeding the strip-shaped body 42 into the calender roll 63, the composite film 43 is formed. The calender roll 63 has a pair of partition members 64 installed on both sides of the strip-shaped body 42, and the width W dimension of the composite film 43 is set by the pair of partition members 64. The peripheral speed of the calender rollers 63a, 63a of the calender roll 63 is set according to the transport speed. The gap between the pair of calender rollers 63a, 63a in the calender roll 63 is set according to the required thickness of the composite film 43, but is made smaller than the gap between the pair of calender rollers 62a, 62a in the calender roll 62 used in the preliminary film formation process.

[0035] [Adhesion process] Figure 5 is a schematic diagram illustrating the bonding process. The composite film 43 formed by the film formation process is cut to predetermined dimensions in the longitudinal direction L and the width direction W, for example, to match the size of the current collector foil 5 to which it is bonded. As will be described in detail later, in this embodiment the composite film 43 after cutting has a two-layer structure, and the two layers are continuous on one side W1 in the width direction W (right side in the plane of Figure 5), while the two layers are discontinuous on the other side W2 in the width direction W (left side in the plane of Figure 5). Subsequently, the composite film 43A after cutting is bonded to the surface of the current collector foil 5 by hot roll pressing to form the electrode 1 for the secondary battery (see Figure 6).

[0036] The composite film 43 formed by the film formation process may be cut to a predetermined size, for example, only in the longitudinal direction L, to match the size of the current collector foil 5 to which it is bonded. In this case, the composite film 43 after cutting has a two-layer structure, and the two layers are continuous on both sides in the width direction W. Subsequently, the composite film 43B is bonded to the surface of the current collector foil 5 by hot roll pressing to form the electrode 1 for the secondary battery (see Figure 7).

[0037] In this embodiment, during the extrusion molding process, when forming the cylindrical body 41, the rotating body 31 is rotated at a predetermined peripheral speed, thereby acting a force along the rotation direction of the rotating body 31 on the composite film material 10 flowing down from between the rotating body 31 and the housing portion 33 of the stationary body 34 toward the extrusion port 35. As a result, within the cylindrical body 41, a portion of the binder resin 11 becomes fine fibers that extend along the circumferential direction. In other words, the cylindrical body 41 is in a state where a portion of the finely fibrous binder resin 11 is arranged along the circumferential direction. Then, in the film formation process, the cylindrical body 41 is rolled sequentially from one side in the axial direction (longitudinal direction L), thereby a portion of the binder resin 11 becomes fine fibers that extend along the longitudinal direction L of the composite film 43. In other words, the composite film 43 is in a state where a portion of the finely fibrous binder resin 11 is arranged along the longitudinal direction L. In other words, by performing the extrusion molding process and the film formation process according to this embodiment, the composite film 43 will contain a mixture of fine fibers extending along the width direction W and fine fibers extending along the longitudinal direction L.

[0038] The secondary battery electrode 1 manufactured in this way has a larger ratio of tensile strength in the width direction W to tensile strength in the longitudinal direction L in the composite film 43 compared to conventional methods. Therefore, problems such as breakage during transport due to insufficient strength of the composite film 43 and inability to increase the transport speed are less likely to occur, and the secondary battery electrode 1 can be manufactured more efficiently than before.

[0039] The secondary battery electrode 1 shown in Figure 6 will be described in detail. The secondary battery electrode 1 is a long member comprising a current collector foil 5 and an asphalt film 43A bonded to the current collector foil 5. The asphalt film 43A has a two-layer structure, with the two layers 43A1 and 43A2 being continuous on one side W1 in the width direction, and the two layers 43A1 and 43A2 being discontinuous on the other side W2 in the width direction.

[0040] By configuring the secondary battery electrode 1 in this way, the electrolyte that has entered between the two layers 43A1 and 43A2 constituting the composite film 43A can only flow out from the other side W2 in the width direction W, thus the electrolyte is more easily retained in the composite film 43A of the secondary battery electrode 1. This makes it possible to increase the power generation efficiency of the secondary battery using the secondary battery electrode 1.

[0041] [Second Embodiment] A second embodiment will be described based on Figures 8 and 9. In the second embodiment, a film formation process is performed following the extrusion molding process. That is, the manufacturing method of the secondary battery electrode 1 in the second embodiment differs from the first embodiment in that it does not have a preliminary film formation process. In the following, we will mainly describe in detail the configurations that differ from the first embodiment, and for the sake of convenience, similar configurations will be denoted by the same reference numerals and their detailed descriptions will be omitted.

[0042] In the second embodiment, as shown in Figure 9, a cylindrical body 41 formed by an extrusion molding process is rolled by a calender roll 65 having a pair of calender rollers 65a, 65a as a film-forming process to form an asphalt film 43. The gap between the pair of calender rollers 65a, 65a in the calender roll 65 is set according to the required thickness of the asphalt film 43. Even in this case, the asphalt film 43 can be manufactured based on a cylindrical body 41 in which the arrangement direction of the fine fibers of the binder resin 11 is dispersed in the width direction W and the longitudinal direction L. Therefore, by using this asphalt film 43, various problems caused by insufficient strength of the asphalt film 43 are less likely to occur when manufacturing the electrode 1 for secondary batteries, and electrodes can be manufactured efficiently.

[0043] (Other embodiments) In the above embodiment, the extrusion die 30 is shown to have a rotating body 31 having a tapered portion 36 that gradually decreases in diameter from the extrusion opening 35 toward the opposite side in the axial X direction. Alternatively, the rotating body 31 may have a shape that follows the axis toward the opposite side from the extrusion opening 35 in the axial X direction (in other words, the rotating body 31 may have a shape consisting only of a cylindrical portion 37).

[0044] In the embodiments described above, the secondary battery is exemplified as being installed in an electric vehicle or a hybrid vehicle. However, secondary batteries are not limited to these, and may be installed in vehicles other than electric vehicles or hybrid vehicles, such as gasoline vehicles or diesel vehicles equipped with batteries. Furthermore, secondary batteries may be used as a power source for mobile devices other than automobiles, as a fixed power source, or as a power source other than a motor, as long as they are required as a power source. For example, power sources other than automobiles include mobile devices such as trains, ships, aircraft, and robots, as well as power sources for electrical products such as information processing devices. [Explanation of symbols]

[0045] 1: Electrode for secondary batteries 5: Current collector foil 10: Composite membrane material 11: Binder resin 30: Extrusion mold 31: Solid of revolution 32:Aperture 33: Containment Unit 34: Fixed body 34a: Inner self 35: Extrusion port 36: Tapered section 36a: External surface 41: Cylindrical body 42: Zing 43,43A,43B: Composite material membrane L: Longitudinal direction W: width direction W1: One side in the width direction W2: Other side in the width direction X: Axial center

Claims

1. A method for manufacturing a strip-shaped electrode for a secondary battery, comprising a current collector foil and a composite material film adhered to the current collector foil, An extrusion die comprising a rotating body that rotates around an axis, and a stationary body having a housing portion that communicates with an opening provided in the axial direction and is capable of housing the rotating body, wherein an annular extrusion opening is formed between the rotating body and the inner surface of the housing portion, when viewed in the axial direction, Using a powdered composite film material containing at least an active material, a conductive material, and a binder resin that forms fine fibers, An extrusion molding process in which the composite film material is supplied to the extrusion die while the rotating body is rotating and discharged from the extrusion port to form a cylindrical body in which the binder resin has been finely fibroused, A film forming step is performed in which the cylindrical body formed in the extrusion molding step is rolled sequentially from one axial side to form a composite film, A method for manufacturing an electrode for a secondary battery, comprising an bonding step of bonding the composite film formed in the film formation step to a current collector foil.

2. Between the extrusion molding step and the film formation step, there is a pre-film formation step in which the cylindrical body is rolled sequentially from one side in the axial direction to form a strip-shaped body. The method for manufacturing an electrode for a secondary battery according to claim 1, wherein in the film formation step, the strip-shaped body formed in the preliminary film formation step is rolled sequentially from one side in the longitudinal direction to form an composite film.

3. The extrusion die is The rotating body has a tapered portion that gradually decreases in diameter in the axial direction from the extrusion opening toward the opposite side, The method for manufacturing an electrode for a secondary battery according to claim 1, wherein in the fixed body, the inner surface of the housing portion facing the tapered portion of the rotating body is parallel to the outer surface of the tapered portion.

4. An electrode for a secondary battery manufactured by the method for manufacturing an electrode for a secondary battery described in any one of claims 1 to 3.

5. It is a long member comprising a current collector foil and a composite material film bonded to the current collector foil. The composite film has a two-layer structure, and the two layers are continuous on one side in the width direction, while the two layers are discontinuous on the other side in the width direction, in this electrode for a secondary battery.

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