Method for manufacturing an electrode

Abstract

To provide a manufacturing method of an electrode, capable of suppressing deterioration in quality.SOLUTION: A manufacturing method of an electrode includes: a preparation step of preparing a precursor sheet 10 having a coating part and an uncoating part that are arranged on metal foil; a coating part press step of pressing the coating part; and an uncoating part press step of pressing the uncoating part. The uncoating part is arranged at an end part of the coating part. In the uncoating part press step, roll pressing is performed while applying compressive force by using a pair of elastic rolls each of which has a shaft body 21 and an elastic body 22 covering the shaft body; an elastic roll A (20A) and an elastic roll B (20B) are used as the pair of elastic rolls; and by using a support roll 30, processing to apply a load is performed so as to include an area where the elastic body of the elastic roll B comes into contact with the precursor sheet. The processing is performed such that a load Y that is applied from the support roll to the elastic roll B is greater than a load X that is applied from the elastic roll A to the elastic roll B.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing an electrode.

Background Art

[0002] As a method for manufacturing an electrode, a method of rolling a sheet obtained by applying an electrode composite material onto a long metal foil is known.

[0003] For example, Patent Document 1 discloses a pressing method for a battery electrode having a coated portion coated with an electrode active material and an uncoated portion not coated with the electrode active material. Further, Patent Document 2 discloses a roll pressing method using a roll press machine equipped with a wrinkle prevention device that suppresses the generation of wrinkles generated by roll pressing operations in the coated portion and the uncoated portion of the electrode plate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, when pressing a sheet having a coated portion and an uncoated portion, in order to prevent wrinkles from occurring, the coated portion and the uncoated portion may be pressed individually to adjust the elongation difference. Further, when pressing the uncoated portion, the uncoated portion may be roll-pressed using an elastic roll so that the uncoated portion does not break.

[0006] The inventors have found that when the uncoated portion is pressed using an elastic roll, if the elastic roll rides on the coated portion due to meandering or the like, streaks may occur in the coated portion or the coated portion may break, and the quality of the resulting electrode may deteriorate.

[0007] The present disclosure has been made in view of the above circumstances, and the main object thereof is to provide a method for manufacturing an electrode capable of suppressing deterioration in quality.

Means for Solving the Problems

[0008] [1] A preparation step of preparing a precursor sheet having a metal foil having a longitudinal direction in a first direction, and a coated portion and an uncoated portion disposed on the metal foil; while conveying the precursor sheet in the first direction, pressing the coated portion in the thickness direction, a coated portion pressing step; before or after the coated portion pressing step, while conveying the precursor sheet in the first direction, pressing the uncoated portion in the thickness direction, an uncoated portion pressing step, wherein the coated portion contains an electrode material containing at least an active material, the uncoated portion does not contain the electrode material, and is disposed at an end of the coated portion in a direction orthogonal to the first direction, and in the uncoated portion pressing step, while applying a compressive force for pressing the uncoated portion in the thickness direction using a pair of elastic rolls having a shaft body and an elastic body covering the shaft body, performing roll pressing, using elastic roll A and elastic roll B as the pair of elastic rolls, and during the roll pressing, using a support roll, performing a process of applying a load so as to include a region where the elastic body of the elastic roll B contacts the precursor sheet with respect to the elastic body of the elastic roll B, when the load applied from the elastic roll A to the elastic roll B is load X and the load applied from the support roll to the elastic roll B is load Y, performing the process so that the load Y is larger than the load X, a method for manufacturing an electrode.

[0009] [2] The method for manufacturing an electrode according to [1], wherein the support roll is a metal roll or the elastic roll.

[0010] [3] The elastic roll A has, as the elastic body, two elastic bodies arranged apart from each other. In the rotational axis direction, the length between the outer ends of the two elastic bodies is designated as LX1, the length of the elastic body of the elastic roll B is designated as LX2, and the length of the roller part of the support roll is designated as LX3. In this case, LX2 and LX3 are longer than LX1. The method for manufacturing an electrode according to [1] or [2].

[0011] [4] When observed from the thickness direction, the elastic roll A is arranged such that the elastic body contacts the precursor sheet at a position overlapping with the uncoated part, and is arranged such that the elastic roll A does not contact the precursor sheet at a position overlapping with the coating part. The elastic roll B is arranged such that the elastic body contacts the precursor sheet at a position overlapping with the uncoated part when observed from the thickness direction, and is arranged such that the elastic body contacts the precursor sheet at a position overlapping with the coating part. The method for manufacturing an electrode according to any one of [1] to [3]. [Advantages of the Invention]

[0012] In the present disclosure, there is an effect that an electrode capable of suppressing deterioration in quality can be manufactured. [Brief Description of the Drawings]

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Best Mode for Carrying Out the Invention

[0014] Hereinafter, the method for manufacturing an electrode in the present disclosure will be described in detail. Here, in this specification, when expressing the aspect of arranging one member with respect to another member and simply stating "above", unless otherwise specified, it includes both the case of arranging another member directly above so as to be in contact with one member and the case of arranging another member above one member via another member.

[0015] FIG. 1 is a flowchart showing an example of the method for manufacturing an electrode in the present disclosure. In FIG. 1, first, a precursor sheet having a metal foil having a longitudinal direction in a first direction and a coated portion and an uncoated portion disposed on the metal foil is prepared (preparation step). The coated portion contains an electrode material containing at least an active material. Further, the uncoated portion does not contain the electrode material and is disposed at an end of the coated portion in a direction orthogonal to the first direction. Next, while conveying the precursor sheet in the first direction, the coated portion is pressed in the thickness direction (coated portion pressing step). Then, while conveying the precursor sheet in the first direction, the uncoated portion is pressed in the thickness direction (uncoated portion pressing step). In FIG. 1, the uncoated portion pressing step is performed after the coated portion pressing step, but it may be performed before the coated portion pressing step. Also, in the uncoated portion pressing step, while applying a compressive force for pressing the uncoated portion in the thickness direction using a pair of elastic rolls, roll pressing is performed. And in roll pressing, a predetermined load is applied to a predetermined region of the elastic roll B by a support roll. Here, in the present disclosure, the "thickness direction" is synonymous with the lamination direction of the metal foil and the coated portion. Also, in the present disclosure, the "axial direction of the rotation axis" may be referred to as the "axial direction of the shaft body".

[0016] According to the present disclosure, in the roll press, in order to perform a process such that the load Y applied from the support roll to the elastic roll B is greater than the load X applied from the elastic roll A to the elastic roll B, even when the roll rides onto the coating section due to meandering or the like, breakage or the like can be suppressed, and deterioration in the quality of the obtained electrode can be suppressed.

[0017] As a method for manufacturing an electrode, a method of pressing a precursor sheet in which an electrode mixture is applied onto a metal foil (current collector foil) is known. Further, due to the presence or absence of the electrode mixture, a difference in elongation rate occurs after pressing between the coated portion and the uncoated portion of the metal foil, and wrinkles may occur in the electrode. In this regard, as in Patent Document 1 described above, the coated portion and the uncoated portion are pressed individually to suppress the occurrence of wrinkles. Further, in the pressing of the uncoated portion (metal foil), in some cases, a pair of elastic rolls are used to perform roll pressing while applying a compressive force that presses in the thickness direction. By performing such roll pressing, it is possible to apply, to the uncoated portion, a deformation force resulting from the deformation of the elastic body together with the above-described compressive force. Thereby, for example, breakage of the uncoated portion can be effectively prevented.

[0018] Here, generally, the metal foil contains a hard tissue harder than the material of the metal foil as an inclusion. By including the hard tissue, for example, the strength of the metal foil can be increased. When a tensile force (horizontal force) for stretching the metal foil is applied, although the hard tissue does not deform, the surrounding metal foil softer than the hard tissue deforms. As a result, voids are formed around the hard tissue. And when a plurality of voids are connected to each other, breakage is likely to occur. On the other hand, in the present disclosure, a pair of elastic rolls are used to perform roll pressing while applying a compressive force that presses in the thickness direction. Thereby, it is considered that generation of voids around the hard tissue can be suppressed. The compressive force corresponds to a force in the thickness direction, and the deformation force corresponds to a force in a direction orthogonal to the thickness direction. That is, the deformation force acts in the same direction as the tensile force and is a force that stretches the metal foil in the same manner as the tensile force.

[0019] The mechanism that causes the problems in the present disclosure will be described with reference to FIG. 2. FIG. 2(a) is a schematic side view of the precursor sheet and a pair of elastic rolls as viewed from the direction of the rotation axis of the elastic rolls. FIG. 2(b) is a schematic front view of FIG. 2(a) as viewed from the first direction of the metal foil. Note that the precursor sheet is omitted in FIG. 2(b). FIGS. 2(c) and (d) are a schematic front view and a partial front view illustrating the case where the elastic roll rides onto the coating section. As shown in FIGS. 2(a) and (b), when roll pressing is performed on the uncoated section 3 using a pair of elastic rolls 20A and 20B, the shape of the elastic roll A may be transferred to the elastic roll B, and distortion (unevenness) may occur in the elastic roll B. Also, due to the nature of roll pressing, before the distortion is completely eliminated, a compressive force is applied again to the portion where the distortion has occurred, so the distortion remains during roll pressing. In other words, permanent distortion occurs in the elastic roll B. In particular, such distortion becomes more prominent when the elastic roll A is a stepped roll and the elastic roll B is a cylindrical roll (non-stepped roll). When such distortion occurs, the region where the elastic roll B contacts the precursor sheet becomes non-flat. Therefore, as shown in FIG. 2(c), when the elastic roll rides onto the coating section due to meandering or the like in a distorted state and a compressive force is applied to the precursor sheet, as shown in FIG. 2(d), a difference may occur in the distance (clearance) between the elastic roll A and the elastic roll B. In that case, shear stress may concentrate in the portion with a small clearance, which may cause streaks to occur in the coating section or the coating section to break. As a result, the quality of the obtained electrode may deteriorate.

[0020] In contrast, in the present disclosure, as shown in FIGS. 3(a) and (b), during roll pressing, a process is performed in which a predetermined load is applied to the elastic roll B (20B) by the support roll 30. Thereby, the strain generated by the pressing of the elastic roll A (20A) can be evened out. Also, the amount of strain (depth of the dent) can be reduced. As a result, as shown in FIG. 3(c), the region of the elastic roll B in contact with the precursor sheet can be flattened. Therefore, even when the elastic roll A (20A) rides onto the coating section of the precursor sheet, no difference or a small difference occurs in the distance (clearance) between the elastic roll A and the elastic roll B. As a result, the concentration of shear stress is alleviated, and the occurrence of streaks in the coating section or breakage of the coating section can be suppressed.

[0021] Furthermore, in the present disclosure, as shown in FIG. 3(b), the region R1 where a load is applied from the support roll 30 to the elastic roll B (20B) includes the region R2 where the elastic body 22 of the elastic roll B (20B) contacts the precursor sheet. Therefore, the width evened out by the support roll of the elastic roll B can be widened with respect to the width of the precursor sheet. And even when the elastic roll A rides onto the coating section, it is possible to prevent the precursor sheet from riding onto the shoulder on the outer side of the elastic roll B (the shoulder of the dent shown in FIG. 3(c)). As a result, the occurrence of streaks and breakage can be further suppressed. Note that the "region where the elastic body of the elastic roll B contacts the precursor sheet" can be regarded as, for example, the region where the elastic body of the elastic roll B is in contact with the precursor sheet at the start of roll pressing.

[0022] 1. Preparation step The preparation step in the present disclosure is a step of preparing a precursor sheet having a metal foil having a longitudinal direction in a first direction, and a coating section and an uncoated section disposed on the metal foil.

[0023] FIG. 4 is a schematic plan view illustrating the precursor sheet prepared in the preparation step. As shown in FIG. 4, the precursor sheet 10 has a metal foil 1 having a longitudinal direction in a first direction D, a coating section 2, and an uncoated section 3.

[0024] Examples of the material of the metal foil include metals used as the material of the current collector of the battery. Details will be described in "4. Electrodes". The thickness of the metal foil is, for example, 1 μm or more, and may be 10 μm or more. On the other hand, the thickness of the metal foil is, for example, 100 μm or less.

[0025] The coated portion of the precursor sheet contains an electrode material containing at least an active material. Further, the coated portion is disposed on the metal foil. The coated portion becomes an electrode layer through a coated portion pressing process described later.

[0026] The electrode material contains at least an active material. Further, the electrode material may contain at least one of a solid electrolyte, a conductive material, and a binder as required. The active material, conductive material, and binder are described in "4. Electrodes".

[0027] In the thickness direction, the coated portion may be disposed only on the first surface of the metal foil, or may be disposed on both the first surface and the second surface opposite to the first surface.

[0028] The coated portion is preferably disposed along the first direction of the metal foil. Further, as shown in FIG. 4, the coated portion may be continuously disposed along the first direction D of the metal foil 1. On the other hand, the coated portion 1 may be intermittently disposed along the first direction D of the metal foil 1.

[0029] The thickness of the coated portion is not particularly limited and can be appropriately adjusted according to the desired electrode size. The thickness of the coated portion is, for example, 0.2 mm or more, and may be 0.3 mm or more, or may be 0.5 mm or more. On the other hand, the thickness of the coated portion is, for example, 1.5 mm or less, and may be 1.0 mm or less, or may be 0.6 mm or less.

[0030] The width of the coating section (the length in the second direction orthogonal to the first direction of the metal foil) is not particularly limited and can be appropriately adjusted according to the desired electrode size. The ratio of the width of the coating section to the width of the metal foil may be, for example, 30% or more, may be 50% or more, or may be 70% or more. Also, the above ratio may be, for example, 90% or less, or may be 80% or less.

[0031] The uncoated section is disposed on the metal foil. Also, the uncoated section is usually disposed on the same surface as the surface of the metal foil on which the coating section is disposed. The uncoated section is, for example, a portion where the metal foil is exposed. As shown in FIG. 4, in the present disclosure, the uncoated section 3 is disposed at the end of the coating section 2 in the direction orthogonal (second direction) to the first direction D of the metal foil 1. Also, although not shown, in the uncoated section, a protective layer containing a resin may be provided at the boundary portion with the coating section.

[0032] The width of the uncoated section (the length in the second direction) is not particularly limited and can be appropriately adjusted according to the desired electrode size. The ratio of the width of the uncoated section to the width of the metal foil may be, for example, 3% or more, or may be 5% or more. On the other hand, the above ratio may be, for example, 20% or less, or may be 10% or less.

[0033] The precursor sheet can be prepared, for example, by coating an electrode material containing a dispersion medium on a metal foil and drying it. Examples of the dispersion medium include organic solvents such as butyl butyrate, dibutyl ether, and heptane. The coating method of the electrode material is not particularly limited, and general coating methods can be mentioned. Also, the drying temperature is not particularly limited as long as it is a temperature at which the dispersion medium volatilizes.

[0034] The precursor sheet prepared in the preparation step may be, for example, a precursor sheet 10 having, in plan view, a stripe-like arrangement of one row of coating sections 2 and two rows of uncoated sections 3 disposed at both ends of the coating section 2, as shown in FIG. 4. Also, although not shown, the precursor sheet may be a sheet having, in plan view, N rows (N is an integer of 2 or more) of coating sections and uncoated sections disposed at both ends of each of the N rows of coating sections. In this case, the number of rows of the uncoated sections is N + 1 rows.

[0035] 2. Coating Department Pressing Process The coating department pressing process is a process of pressing the coating department in the thickness direction while conveying the precursor sheet in the first direction. The coating department pressing process may be performed before or after the uncoated department pressing process described later.

[0036] The method and conditions of the coating department pressing process are not particularly limited as long as the coating department can be pressed and stretched. Examples of the pressing method include a roll pressing method of roll-pressing the coating department. For example, while passing the precursor sheet between a pair of press rolls, the coating department can be pressed by pressing the press rolls against both surfaces of the precursor sheet in the thickness direction.

[0037] The compressive force in the coating department pressing process is not particularly limited, but it is preferably greater than the compressive force in the uncoated department pressing process described later. In the coating department of the precursor sheet, wrinkles may occur due to wetting with the electrode material (slurry) containing the dispersion medium, and a large stretching force is required to stretch these wrinkles.

[0038] 3. Uncoated Department Pressing Process In the uncoated department pressing process in the present disclosure, the uncoated department is pressed in the thickness direction while conveying the precursor sheet in the first direction, before or after the coating department pressing process.

[0039] By pressing the uncoated department, the uncoated department can be stretched to adjust the elongation difference from the coating department. The elongation amount of the uncoated department can be adjusted by changing the deformation force caused by the deformation of the elastic body.

[0040] Here, the details of the press process in the uncoated part will be described with reference to FIGS. 3 and 5. FIG. 5(a) is a view of the precursor sheet and the elastic roll A in the roll press, observed from the side of the elastic roll A in the thickness direction. FIG. 5(b) is a view of the precursor sheet and the elastic roll B in the roll press, observed from the side of the elastic roll B in the thickness direction. Note that the support roll is omitted in FIG. 5(b).

[0041] In the press process in the uncoated part in the present disclosure, as shown in FIG. 3(a), a pair of elastic rolls (20A, 20B) having a shaft body 21 and an elastic body 22 covering the shaft body 21 are used to apply a compressive force to press the uncoated part 3 in the thickness direction while performing roll pressing. Also, in the roll pressing, a predetermined process is performed using a support roll. By using a pair of elastic rolls, both the compressive force by pressing the elastic roll against the precursor sheet and the deformation force of the elastic body caused by the compressive force can be applied to the uncoated part, so that breakage of the uncoated part can be effectively prevented. The compressive force is not particularly limited, but for example, it is 10 kgf / cm or more and 200 kgf / cm or less. Note that, as shown in FIG. 3(b) and the like, in the axial direction of the rotating shaft, the shaft body usually protrudes from the elastic body toward the outside of the elastic roll.

[0042] The material of the shaft body is not particularly limited, but a material having a larger Young's modulus than the elastic body is preferable. Examples of the material of the shaft body include metals.

[0043] Also, the elastic body preferably has a predetermined Young's modulus. The Young's modulus is, for example, 11.1 MPa or more and 86.1 MPa or less. Examples of the material of the elastic body include resins such as rubber and urethane.

[0044] The support roll may be a metal roll or the above elastic roll. As shown in FIG. 3(b) etc., a metal roll usually has a roller part 32 and a shaft part 31 protruding from the roller part. The roller part and the shaft part may be an integral member or different members. Note that the roller part refers to the part of the support roll that contacts the elastic roll B. Regarding the materials of the metal part and the shaft body, they can be the same as those of the shaft body of the above elastic roll. The elastic roll is as described above.

[0045] As shown in FIGS. 3(b) and (c), the elastic roll A is preferably a so-called stepped roll in which two or more portions of the shaft body in the axial direction of the rotating shaft are covered with the above-described elastic body. In particular, the elastic roll A is preferably a so-called two-wheeled stepped roll having two elastic bodies arranged apart from each other as the above elastic body. Further, the elastic roll B and the support roll are preferably so-called cylindrical rolls.

[0046] Also, as shown in FIG. 3(b), in the rotating shaft direction X, when the length between the outer ends of the two elastic bodies 22 of the elastic roll A (20A) is LX1, the length of the elastic body 22 of the elastic roll B (20B) is LX2, and the length of the roller part 32 of the support roll 30 is LX3, it is preferable that LX2 and LX3 are longer than LX1.

[0047] LX1 is usually a length equal to or longer than the length in the second direction of the metal foil. Also, LX2 / LX1 with respect to LX1 and LX3 / LX1 with respect to LX1 are each, for example, 1.1 or more, and may be 1.2 or more, or 1.3 or more. On the other hand, LX2 / LX1 and LX3 / LX1 are each, for example, 2.0 or less, and may be 1.8 or less, or 1.5 or less.

[0048] Also, LX2 and LX3 may be the same or different. For example, when LX2 / LX3 is 0.9 or more and 1.1 or less, LX2 and LX3 are the same. When LX2 and LX3 are different, LX2 may be longer or shorter than LX3. In this case, LX2 / LX3 is, for example, 0.7 or more and 1.3 or less.

[0049] In addition, in the roll press, using a support roll, a process of applying a load is performed so as to include a region where the elastic body of the elastic roll B contacts the precursor sheet with respect to the elastic body of the elastic roll B. Further, when the load applied from the elastic roll A to the elastic roll B is defined as load X and the load applied from the support roll to the elastic roll B is defined as load Y, the above process is performed so that load Y is greater than load X. When load Y is the same as or smaller than load X, it becomes difficult to sufficiently eliminate the strain (dent) generated in roll B.

[0050] The difference between load X and load Y is not particularly limited as long as X < Y is satisfied. For example, load X with respect to load Y (Y / X) is, for example, 1.1 or more, and may be 1.2 or more, or may be 1.3 or more. On the other hand, Y / X is, for example, 2.0 or less, and may be 1.8 or less, or may be 1.5 or less.

[0051] The numerical values of load X and load Y are not particularly limited, but for example, they are each 10 kgf / cm or more and 200 kgf / cm or less.

[0052] The above process may be continuously performed during the roll press. On the other hand, the above process may be intermittently performed at any timing during the roll press. For example, when it is detected that a strain amount equal to or greater than a threshold value has occurred in the elastic roll B during the roll press, the above process may be performed.

[0053] Further, when observed from the thickness direction, the elastic roll A (20A) is arranged such that the elastic body 22 contacts the precursor sheet 10 at a position overlapping with the uncoated portion 3, and is arranged such that the elastic roll A (20A) does not contact the precursor sheet 10 at a position overlapping with the coating portion 2, which is preferable. In this case, as shown in Fig. 5(a), the elastic roll A (20A) includes a first contact portion C1 where the elastic body 22 is arranged at a position overlapping with the uncoated portion 3, and a non-contact portion N1 that does not contact the precursor sheet (the coating portion 2 in Fig. 5(a)) at a position overlapping with the coating portion 2. Note that when the coating portion is arranged only on one side of the metal foil, the non-contact portion N1 may be a portion that does not contact the metal foil in the precursor sheet during roll pressing. Further, the non-contact portion N1 is typically a portion where the elastic body is not arranged. The elastic body in the first contact portion C1 contacts the uncoated portion 3 in the uncoated portion pressing process. On the other hand, the non-contact portion N1 usually does not contact the precursor sheet in the uncoated portion pressing process. Also, as shown in Fig. 5(a), the roll A (20A) includes the first contact portion C1 at both end portions of the non-contact portion N1, respectively.

[0054] Further, when observed from the thickness direction, the elastic roll B (20B) is arranged such that the elastic body 22 contacts the precursor sheet 10 at a position overlapping with the uncoated portion 3, and is arranged such that the elastic body 22 contacts the precursor sheet 10 at a position overlapping with the coating portion 2, which is preferable. In this case, as shown in Fig. 5(b), the elastic roll B (20B) includes a second contact portion C2 where the elastic body 22 is arranged at a position overlapping with the uncoated portion 3 when observed from the thickness direction, and a third contact portion C3 that contacts the precursor sheet (the coating portion 2 in Fig. 5(b)) at a position overlapping with the coating portion 2. Also, the elastic body in the second contact portion C2 contacts the uncoated portion 3 in the uncoated portion pressing process. On the other hand, the third contact portion C3 contacts the coating portion in the uncoated portion pressing process.

[0055] Further, the elastic roll A is preferably disposed above the precursor sheet, and the elastic roll B and the support roll are preferably disposed below the precursor sheet. Also, for the elastic roll B and the support roll, when viewed from the side as shown in Fig. 3(a), it is preferable that the line connecting the center point of the elastic roll B and the center point of the support roll is parallel to the line in the above thickness direction.

[0056] 4. Electrode In the electrode manufactured by the method of the present disclosure, an electrode layer is formed on at least one surface of the metal foil. The electrode layer is a layer obtained by pressing the above coating section. The electrode manufactured by the method of the present disclosure may be a positive electrode or a negative electrode. That is, the electrode layer may be a positive electrode layer or a negative electrode layer.

[0057] The metal foil typically functions as a current collector foil (current collector). That is, the metal foil may be a positive electrode current collector or a negative electrode current collector. When the metal foil is a positive electrode current collector, examples of the material of the metal foil include Al, SUS, and Ni. When the metal foil is a negative electrode current collector, examples of the material of the metal foil include Cu, SUS, and Ni.

[0058] The electrode layer contains at least an active material. When the electrode layer is a positive electrode layer, the active material is a positive electrode active material. Typical examples of the positive electrode active material include oxide active materials. Examples of the oxide active material include rock salt layer type active materials such as LiCoO2, LiMnO2, LiNiO2, LiVO2, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 and the like, spinel type active materials such as LiMn2O4, Li(Ni 0.5 Mn 1.5 )O4 and the like, and olivine type active materials such as LiFePO4, LiMnPO4, LiNiPO4, and LiCuPO4.

[0059] When the electrode layer is the negative electrode layer, the active material is a negative electrode active material. Examples of the negative electrode active material include a carbon active material, an oxide active material, and a metal active material. Examples of the carbon active material include mesocarbon microbeads (MCMB), highly oriented pyrolytic graphite (HOPG), hard carbon, and soft carbon. Examples of the oxide active material include Nb2O5, Li4Ti5O 12 and SiO. Examples of the metal active material include In, Al, Si, and Sn.

[0060] Further, the electrode layer may contain at least one of a conductive material and a binder, if necessary.

[0061] Examples of the conductive material include a carbon material, metal particles, and a conductive polymer. Examples of the carbon material include particulate carbon materials such as acetylene black (AB) and ketjen black (KB); fibrous carbon materials such as carbon fiber, carbon nanotube (CNT), and carbon nanofiber (CNF). Examples of the binder include fluorine-containing binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), rubber-based binders such as butadiene rubber, and acrylic binders.

[0062] Examples of the use of the electrode in the present disclosure include a Li-ion battery. Further, the battery in the present disclosure may be a liquid-based battery in which the electrolyte layer contains a liquid-based electrolyte (electrolyte solution). The use of the battery in the present disclosure is not particularly limited, and examples thereof include power sources for vehicles such as hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), battery electric vehicles (BEV), gasoline vehicles, and diesel vehicles. In particular, it is preferably used as a driving power source for a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a battery electric vehicle. Further, the battery in the present disclosure may be used as a power source for a moving body other than a vehicle (for example, a railway, a ship, an aircraft), or may be used as a power source for an electric product such as an information processing device.

[0063] Note that the present disclosure is not limited to the above-described embodiments. The above-described embodiments are examples, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits the same operational effects is included in the technical scope of the present disclosure.

Example

[0064] [Experimental Example 1] A rubber (elastic body) having a predetermined Young's modulus was prepared. Using an autograph device, the jig was repeatedly pressed against the rubber and returned to its original position, and the stress generated at that time was measured. The results are shown in Fig. 6(a).

[0065] As shown in Fig. 6(a), it was confirmed that permanent strain occurred in the rubber with the first load, and due to the influence of the strain generated with subsequent loads, stress did not occur until the jig moved by the amount of strain (depth). Thus, it was confirmed that permanent strain occurs in the elastic body when roll pressing is performed using the elastic body.

[0066] [Experimental Example 2] By CAE analysis, the shear stress applied to the electrode sheet was simulated under three conditions of permanent strain amount (depth of dent) of 0 μm, 300 μm, and 600 μm. The results are shown in Fig. 6(b). Also, an image of the CAE analysis under the condition of a permanent strain amount of 600 μm is shown in Fig. 6(c).

[0067] As shown in Fig. 6(b), it was confirmed that the maximum shear stress applied to the electrode sheet decreases as the permanent strain amount decreases.

[0068] [Experimental Example 3-1] An elastic roll with a diameter of 150 mm and an elastic body thickness of 10 mm was prepared. A load of 131 kgf / cm was applied to this elastic roll to form a permanent strain (dent) in the elastic roll, and the permanent strain amount (depth of dent) was measured. The results are shown in Fig. 6(d).

[0069] [Experimental Example 3-2] For the elastic roll in which a permanent strain was formed in Experimental Example 2-1, as shown in Fig. 3(b), the roll (support roll) was pressed against it with a load greater than 131 kgf / cm. The amount of permanent strain (depth of the dent) after pressing was measured. The results are shown in Fig. 6(d).

[0070] As shown in Fig. 6(d), it was confirmed that the amount of permanent strain can be reduced by pressing the support roll against the elastic roll in which permanent strain has occurred.

[0071] From the above experimental results, it was confirmed that by performing a process such that the load Y applied from the support roll to the elastic roll B is greater than the load X applied from the elastic roll A to the elastic roll B during roll pressing, the amount of permanent strain can be reduced and the maximum shear stress applied to the precursor sheet can be reduced. Thereby, it was shown that in the method for manufacturing an electrode according to the present disclosure, even when the elastic roll rides on the coating section due to meandering or the like, breakage or the like can be suppressed and deterioration in the quality of the obtained electrode can be suppressed.

Description of Reference Numerals

[0072] 1... Metal foil 2... Coating section 3... Uncoated section 10... Precursor sheet 21... Shaft body 22... Elastic body 20... Elastic roll 20A... Elastic roll A 20B... Elastic roll B 30... Support roll

Claims

1. A preparation step of preparing a precursor sheet having a metal foil with a longitudinal direction in a first direction, and a coated portion and an uncoated portion disposed on the metal foil; A coated portion pressing step of pressing the coated portion in a thickness direction while transporting the precursor sheet in the first direction; An uncoated portion pressing step of pressing the uncoated portion in the thickness direction while transporting the precursor sheet in the first direction, before or after the coated portion pressing step; characterized by comprising: The coated portion contains an electrode material including at least an active material; The uncoated portion does not contain the electrode material and is disposed at an end portion of the coated portion in a direction orthogonal to the first direction; In the uncoated portion pressing step, while applying a compressive force for pressing the uncoated portion in the thickness direction using a pair of elastic rolls having a shaft body and an elastic body covering the shaft body, roll pressing is performed; As the pair of elastic rolls, elastic roll A and elastic roll B are used; The elastic roll A has an elastic body A as the elastic body; The elastic roll B has an elastic body B as the elastic body; During the roll pressing, using a support roll, a process of applying a load is performed so as to include a region where the elastic body B of the elastic roll B contacts the precursor sheet with respect to the elastic body B of the elastic roll B; When the load applied from the elastic roll A to the elastic roll B is load X and the load applied from the support roll to the elastic roll B is load Y, the process is performed such that the load Y is greater than the load X; The support roll is a metal roll or an elastic roll (excluding an elastic roll provided with an elastic body softer than the elastic body B); The elastic roll A has two elastic bodies a disposed apart from each other as the elastic body A; In the rotational axis direction, when the length between the outer ends of the two elastic bodies a is LX1, the length of the elastic body B of the elastic roll B is LX2, and the length of the roller portion of the support roll is LX3, the LX2 and the LX3 are longer than the LX1. A method for manufacturing an electrode.

2. The method for manufacturing an electrode according to claim 1, wherein the support roll is the metal roll or the elastic roll having the same elastic body as the elastic body B.

3. When observed from the thickness direction, the elastic roll A is arranged such that the elastic body A contacts the precursor sheet at a position overlapping with the uncoated portion, and has a portion where the elastic roll A does not contact the precursor sheet at a position overlapping with the coating portion. The method for manufacturing an electrode according to claim 1, wherein the elastic roll B is arranged such that the elastic body B contacts the precursor sheet at a position overlapping with the uncoated portion when observed from the thickness direction, and the elastic body B contacts the precursor sheet at a position overlapping with the coating portion.

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