Electrode sheet manufacturing apparatus, method for manufacturing electrode sheet, and method for manufacturing battery
The method addresses wrinkles in electrode sheets by using a rubber roll and stepped roll pressing to uniformly stretch the current collector, ensuring a stable electrode sheet production process.
Patent Information
- Application Number
- JP2024086693
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-05-28
- Publication Date
- 2025-12-10
AI Technical Summary
Wrinkles occur in electrode sheets during the roll-pressing process due to differences in elongation rates between the uncoated and coated portions, leading to improper stretching and potential breakage of the uncoated edges.
A manufacturing method and apparatus that includes a first pressing step using a rubber roll to stretch the uncoated portion, followed by a stepped roll pressing step with a larger diameter at the boundary to uniformly stretch the current collector, and a second pressing step to adjust the active material layer density, minimizing wrinkles and breakage.
The method effectively suppresses wrinkles and ensures proper stretching of the electrode sheet, particularly at the boundary between the uncoated and coated areas, resulting in a stable electrode sheet production process.
Smart Images
Figure 2025179749000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to an electrode sheet manufacturing apparatus, an electrode sheet manufacturing method, and a battery manufacturing method. [Background technology]
[0002] Japanese Patent Application Laid-Open Publication No. 2023-36089 discloses a method for manufacturing an electrode sheet having a coated portion on a metal foil where an active material layer containing an electrode material is coated, and an uncoated portion is set at the end of the coated portion. The manufacturing method disclosed in this publication discloses that when the electrode sheet is roll-pressed, the uncoated portion is pressed with a pair of elastic rolls. By pressing the uncoated portion with a pair of elastic rolls, it is possible to apply a compressive force and a deforming force to the same location on the uncoated portion. This is said to enable the uncoated portion to be stretched while suppressing breakage of the uncoated portion. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-36089 Summary of the Invention [Problem to be solved by the invention]
[0004] Incidentally, the present inventors have found that when an electrode sheet is roll-pressed, wrinkles may occur in the electrode sheet even when the uncoated portion is pressed with a pair of elastic rolls. [Means for solving the problem]
[0005] The electrode sheet manufacturing apparatus disclosed herein is a manufacturing apparatus for manufacturing an electrode sheet having a current collector made of a long metal foil, an unformed portion set along the length of the current collector at a predetermined position in the width direction, and an active material layer formed on the current collector except for the unformed portion. The electrode sheet manufacturing apparatus includes a roll press unit that roll-presses the electrode sheet. The roll press unit includes a conveying device that conveys the electrode sheet along a predetermined conveying path, a first press device that is arranged on the conveying path and presses out the unformed portion of the electrode sheet with a rubber roll, a stepped roll pressing device that is arranged on the conveying path downstream of the first press device and presses a stepped roll against the electrode sheet, and a second press device that is arranged on the conveying path downstream of the stepped roll conveying section and presses out the active material layer of the electrode sheet with a roll press. The stepped roll has a step at the boundary between the unformed portion and the active material layer, and the diameter of the portion that corresponds to the unformed portion is larger than the diameter of the portion that corresponds to the active material layer.
[0006] This electrode sheet manufacturing apparatus can suppress wrinkles in the electrode sheet caused by the difference in elongation rate of the current collector between the boundary portion with the active material layer in the unformed portion and the other portions.
[0007] The method for manufacturing an electrode sheet disclosed herein includes a first pressing step in which an unformed portion of the electrode sheet is pressed and stretched with a rubber roll while the electrode sheet is transported along a predetermined transport path; a stepped roll pressing step in which, after the first pressing step, the electrode sheet is pressed and transported against a stepped roll that has a step in the portion of the unformed portion that corresponds to the boundary with the active material layer and has a larger diameter than the portion of the unformed portion that corresponds to the active material layer; and a second pressing step in which, after the stepped roll pressing step, the active material layer of the electrode sheet is pressed and stretched with a roll press.
[0008] This electrode sheet manufacturing method can provide an electrode sheet in which wrinkles caused by a difference in elongation rate between the boundary portion with the active material layer and other portions of the current collector in the unformed portion are suppressed. Furthermore, the electrode sheet manufacturing method can be applied to a battery manufacturing method. [Brief explanation of the drawings]
[0009] [Figure 1] FIG. 1 is a flow diagram of the manufacturing method for an electrode sheet. [Figure 2] FIG. 2 is a schematic diagram of the electrode sheet 10. [Figure 3] FIG. 3 is a schematic diagram showing another embodiment of the electrode sheet 10. In FIG. [Figure 4] FIG. 4 is a schematic diagram showing an example of the roll press step S6 proposed here. [Figure 5] FIG. 5 is a schematic diagram of the first pressing step S6a. [Figure 6] FIG. 6 is a schematic diagram of the stepped roll pressing step S6c. DETAILED DESCRIPTION OF THE INVENTION
[0010] An embodiment of the technology disclosed herein will be described below with reference to the drawings. The embodiments described herein are, of course, not intended to limit the present invention. The drawings are schematic and do not necessarily reflect the actual product. Furthermore, members and parts that perform the same function are appropriately designated by the same reference numerals, and redundant explanations are appropriately omitted. In this specification, expressions such as "X to Y" that indicate a numerical range mean "X or more and Y or less," unless otherwise specified.
[0011] Fig. 1 is a flow diagram of the manufacturing method of an electrode sheet. As shown in Fig. 1, the manufacturing method of an electrode sheet includes a conveying step S1, a measuring step S2, a kneading step S3, a coating step S4, a drying step S5, and a roll pressing step S6. However, the manufacturing method of an electrode sheet may include other steps.
[0012] <Electrode sheet 10> 2 is a schematic diagram of an electrode sheet 10. The electrode sheet 10 constitutes the positive electrode sheet or negative electrode sheet of an electrode body housed inside an electricity storage device. An electricity storage device refers to a device that can be repeatedly charged and discharged, and is a concept that encompasses so-called storage batteries (i.e., chemical batteries) such as lithium ion secondary batteries, nickel-metal hydride batteries, nickel-cadmium batteries, and other such batteries, as well as capacitors (i.e., physical batteries) such as electric double layer capacitors.
[0013] As shown in FIG. 2 , the electrode sheet 10 includes a current collector 12 and an active material layer 14. The current collector 12 is a member made of metal foil. The current collector 12 is a long, strip-shaped metal member. A metal material having a required conductivity can be used for the current collector 12. For example, aluminum or an aluminum alloy can be used for the positive electrode current collector foil. For example, copper or a copper alloy can be used for the negative electrode current collector foil. The active material layer 14 is coated at a predetermined position on the current collector 12. The active material layer 14 is formed on at least one surface of the strip-shaped current collector 12. In this embodiment, the active material layer 14 is formed on both surfaces of the current collector 12. The active material layer 14 is a layer containing an electrode active material. For example, a lithium transition metal composite oxide can be used for the positive electrode active material. For example, a carbon material, a silicon-based material, or a mixed oxide thereof can be used for the negative electrode active material. The active material layer may contain additives other than the electrode active material, such as a binder and a conductive material.
[0014] The electrode sheet 10 is formed by applying an electrode mixture slurry that will become the active material layer 14 to a current collector 12 and drying the applied slurry. The current collector 12 has uncoated portions 12a (unformed portions) and coated portions 12b. The uncoated portions 12a are portions of the current collector 12 that are not coated with the active material layer 14. The uncoated portions 12a are set along the length of the ends in the width direction of the electrode sheet 10. In this embodiment, the uncoated portions 12a are set at both ends in the width direction of the electrode sheet 10. The coated portions 12b are arranged between the uncoated portions 12a at both ends of the electrode sheet 10. The electrode mixture slurry is applied to the coated portions 12b. As a result, the active material layer 14 is formed in the coated portions 12b of the current collector 12. That is, the active material layer 14 is arranged between the uncoated portions 12a at both ends in the width direction of the electrode sheet 10. In this way, the electrode sheet preferably has a current collector 12 made of a long metal foil, an unformed portion (here, an uncoated portion 12a) set along the length of the current collector 12 at a predetermined position in the width direction, and an active material layer 14 formed on the current collector 12 in a portion other than the unformed portion.
[0015] FIG. 3 is a schematic diagram illustrating another embodiment of the electrode sheet 10. As shown in FIG. 3, the electrode sheet 10 may have an insulating protective layer 12c in the uncoated portion 12a adjacent to the coated portion 12b. This structure may be employed, for example, in an electrode sheet 10 used for a positive electrode. The provision of this protective layer 12c on an electrode sheet 10 used for a positive electrode can prevent short circuits between the positive electrode current collector foil and the negative electrode active material layer. The protective layer 12c contains an insulating inorganic filler. An example of the inorganic filler is insulating particles, such as ceramic particles of alumina. The protective layer 12c may contain, for example, a binder. The binder may be the same as the binder exemplified as one that may be contained in the positive electrode active material layer. Hereinafter, unless otherwise specified, reference will be made to FIGS. 2 and 3 for the components of the electrode sheet 10, as appropriate.
[0016] <Transportation process S1, measurement process S2, kneading process S3, coating process S4, drying process S5> In a conveying step S1 shown in FIG. 1, the electrode sheet 10 is conveyed. In the conveying step S1, the electrode sheet 10 is conveyed along a predetermined conveying path W1. In a weighing step S2, raw materials for the active material layer 14 (see FIG. 2) are weighed. The weighing can be achieved, for example, by a weighing device (not shown) having a balance, a load cell, or the like. The weighed raw materials for the active material layer 14 are mixed in a kneading step S3. The kneading step S3 can be achieved by a kneading device (not shown). The raw materials for the active material layer 14, which have been made into a slurry by the kneading device, are applied to the current collector 12 (see FIG. 2) in a coating step S4. The coating step S4 can be achieved by a coating device (not shown), such as a slit coater, gravure coater, die coater, or comma coater. In a drying step S5, the applied raw materials for the active material layer 14 in a slurry state are dried. The drying step S5 can be achieved by, for example, a drying device (not shown) that emits hot air or infrared rays.
[0017] <Roll press process S6> The roll pressing step S6 is a step of roll pressing the electrode sheet 10. Here, the substrate of the electrode sheet 10 is a metal foil. The electrode sheet 10 has a portion where the active material layer 14 is formed (coated portion 12b) and a portion where the active material layer 14 is not formed (uncoated portion 12a). The main purpose of the roll pressing step S6 is to adjust the active material layer 14 formed by coating to an appropriate density.
[0018] In the roll pressing step S6, the coated portion 12b is roll pressed to achieve an appropriate density for the active material layer 14. When the coated portion 12b is roll pressed, the current collector 12 of the substrate stretches in the coated portion 12b, but the pressure of the press is not directly transmitted to the uncoated portion 12a, making it difficult for the current collector 12 of the substrate to stretch. Therefore, if only the coated portion 12b is pressed, the elongation of the current collector 12 may vary between the coated portion 12b and the uncoated portion 12a. Large variations in the elongation of the current collector 12 between the coated portion 12b and the uncoated portion 12a may cause wrinkles to form in the electrode sheet 10. The uncoated portion 12a is cut into a predetermined shape in a subsequent process to form a tab. At this time, if wrinkles occur at the boundary portion 12d of the uncoated portion 12a with the active material layer 14, the tab may not be formed in the appropriate shape.
[0019] To prevent wrinkles from forming in the electrode sheet 10, it is preferable to stretch the current collector 12 with the uncoated portion 12a before or after roll-pressing the coated portion 12b. One technique for stretching the current collector 12 with the uncoated portion 12a is to press the uncoated portion 12a with a rubber roll. The technique of pressing the uncoated portion 12a with a rubber roll is appropriately referred to as EPS (Elasticity Powered Stretching). Furthermore, an apparatus for pressing the uncoated portion 12a with a rubber roll may be appropriately referred to as an EPS apparatus.
[0020] The present inventors have discovered that wrinkles occur in the electrode sheet 10 even when the uncoated portions 12a are stretched by EPS before and after roll pressing. Wrinkles occur particularly at boundary portions 12d of the uncoated portions 12a where the uncoated portions 12a meet the active material layer 14. The present inventors have discovered that this phenomenon is caused by the fact that, when the uncoated portions 12a are stretched by EPS, boundary portions 12d of the uncoated portions 12a where the uncoated portions meet the active material layer 14 cannot be properly stretched.
[0021] That is, an active material layer 14 is formed on the coated portion 12b. The active material layer 14 is a layer coated with a metal oxide such as a lithium transition metal composite oxide. Pressing the EPS rubber roll against the active material layer 14 can cause the active material layer 14 to peel off. From this perspective, the position of the rubber roll in the EPS is set so that it does not come into contact with the coated portion 12b. As a result, the boundary between the uncoated portion 12a and the coated portion 12b and the surrounding area are less likely to be stretched in the EPS. In addition, a protective layer containing an inorganic filler may be formed at the boundary between the uncoated portion 12a and the coated portion 12b. If a protective layer is formed, when the EPS rubber roll is pressed against the active material layer, the elongation percentage may not be the same between the area where the protective layer is formed and the area where the protective layer is not formed.
[0022] Thus, when uncoated portion 12a is stretched with EPS, it is difficult to properly stretch boundary portion 12d of uncoated portion 12a with active material layer 14. As a result, the inventors believe that distortion remains in boundary portion 12d, causing wrinkles in the electrode sheet.
[0023] Fig. 4 is a schematic diagram showing an example of the roll pressing process S6 proposed herein. As shown in Fig. 4, the roll pressing process S6 includes a first pressing process S6a, a second pressing process S6b, and a stepped roll pressing process S6c.
[0024] The first pressing step S6a is the above-mentioned EPS, and is a step of stretching the uncoated portion 12a of the electrode sheet 10. Fig. 5 is a schematic diagram of the first pressing step S6a. As shown in Fig. 5, the first pressing step S6a is a step of pressing and stretching the uncoated portion 12a of the electrode sheet 10 with a pair of rubber rolls 30 while transporting the electrode sheet 10 along a predetermined transport path.
[0025] As shown in FIG. 5 , the rubber roll 30 is preferably a roll member having an elastic body 32 disposed on a shaft 31. The elastic body 32 used in the rubber roll 30 is preferably an elastic material having a required Young's modulus. Examples of the elastic body 32 include rubber and resins such as urethane. In the first pressing step S6a, the uncoated portion 12a is pressed by the rubber roll 30, and receives a reaction force from the elastic deformation and compressive deformation of the rubber roll, pressing and pulling the portion pressed by the roll. In the first pressing step S6a, the uncoated portion 12a can be stretched without applying a large tension to the electrode sheet 10.
[0026] As shown in FIG. 4, the second pressing step S6b is a step of roll-pressing the active material layer 14 (coated portion 12b) of the electrode sheet 10. This step adjusts the active material layer 14 (coated portion 12b) to a required density. In the second pressing step S6b, as shown in FIG. 4, the electrode sheet 10 is sandwiched between a pair of rolls 41, 42, and the active material layer 14 is compressed. During this process, the current collector 12, which is the substrate, is stretched in the area where the active material layer 14 is formed (coated portion 12b).
[0027] The stepped roll pressing step S6c is a step of locally stretching current collector 12, which is the substrate, at boundary portion 12d (see FIGS. 2 and 3) of uncoated portion 12a with active material layer 14. Fig. 6 is a schematic diagram of the stepped roll pressing step S6c.
[0028] <Stepped Roll 50> As shown in Fig. 6, the stepped roll 50 used in step S6c has a step 51a at a portion 51 of the uncoated portion 12a that corresponds to the boundary portion 12d with the active material layer 14. The diameter of the portion 52 that corresponds to the uncoated portion 12a is larger than the diameter of the portion 53 that corresponds to the active material layer 14. In the configuration shown in Fig. 6, the diameter of the portion 52 that corresponds to the uncoated portion 12a is preferably uniform. The diameter of the portion 53 that corresponds to the active material layer 14 is also uniform.
[0029] Here, the boundary portion 12d between the uncoated portion 12a and the active material layer 14 may be the boundary between the active material layer 14 and the uncoated portion 12a of the electrode sheet 10, or a region near the boundary. The boundary portion 12d between the active material layer 14 and the uncoated portion 12a is defined as a portion where the current collector 12, which is the substrate, is less likely to stretch in the first press step S6a in which the uncoated portion 12a is pressed and stretched, or in the second press step S6b in which the active material layer 14 is roll-pressed. The boundary portion 12d between the active material layer 14 and the uncoated portion 12a may be determined in accordance with the specifications of the electrode sheet 10 and its manufacturing process. The width of the boundary portion 12d between the active material layer 14 and the uncoated portion 12a may be, for example, approximately 3 to 7 mm (e.g., approximately 5 mm). As shown in FIG. 3, a protective layer 12c may be formed on the boundary portion 12d between the active material layer 14 and the uncoated portion 12a.
[0030] The step 51a is provided in a portion 51 of the uncoated portion 12a that corresponds to the boundary portion 12d between the uncoated portion 12a and the active material layer 14. In the embodiment shown in FIG. 6, the height of the step 51a is preferably set to such an extent that the boundary portion 12d between the uncoated portion 12a and the active material layer 14 is stretched when the electrode sheet 10 is wound around the stepped roll 50 and transported. From this perspective, the height of the step 51a also depends on the specifications of the electrode sheet 10 (e.g., the thickness of the current collector 12 and the thickness of the active material layer 14 in the coated portion 12b). If the current collector 12 serving as the substrate for the electrode sheet 10 is, for example, an aluminum foil with a thickness of 12 μm, the tension applied to the electrode sheet 10 when the electrode sheet 10 is wound around the stepped roll 50 and transported is 80 N to 200 N, and may be, for example, approximately 100 N.
[0031] Here, the height h1 of the step 51a is defined as the radial distance of the stepped roll 50 from the portion corresponding to the coated portion 12b to the portion corresponding to the uncoated portion 12a. The height h1 of the step 51a may be, for example, 0.50 mm or more and 1.50 mm or less. The step 51a is configured with an inclined surface 51a1 that is uniformly inclined with respect to the axial direction of the stepped roll 50. The inclination angle of the inclined surface 51a1 may be, for example, 15 degrees or more and 45 degrees or less, preferably 30 degrees, with respect to the axial direction of the stepped roll 50. In addition, the start and end points of the inclined surface 51a1 may be rounded, preferably with an R of 0.5, for example.
[0032] <Method for manufacturing electrode sheet> As shown in FIG. 4, the method for manufacturing the electrode sheet 10 proposed here is performed in the following order: a first pressing step S6a, a stepped roll pressing step S6c, and a second pressing step S6b. According to the method for manufacturing the electrode sheet 10 proposed here, the uncoated portion 12a of the electrode sheet 10 is first stretched in the first pressing step S6a. Then, the stepped roll pressing step S6c stretches the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14. Then, the second pressing step S6b further stretches the coated portion 12b. In this case, the electrode sheet 10 is stretched stepwise from the outside: the uncoated portion 12a, the boundary portion 12d of the uncoated portion 12a with the active material layer 14, and the coated portion 12b. This reduces wrinkles caused by the difference in elongation rate of the current collector 12 between the boundary portion 12d of the uncoated portion 12a with the active material layer 14 and the other portions 12a, 12b, and reduces wrinkles throughout the electrode sheet 10.
[0033] In the first pressing step S6a, an EPS device that presses the uncoated portion 12a with a rubber roll 30 is preferably used. In this case, the position and pressing force of the rubber roll 30 are preferably adjusted in the EPS device so that the uncoated portion 12a is pressed by the rubber roll 30. Furthermore, the position of the electrode sheet 10 transported toward the EPS device is preferably adjusted so that the position of the uncoated portion 12a is aligned with the rubber roll 30 of the EPS device. In the stepped roll pressing step S6c, the position of the electrode sheet 10 is preferably adjusted relative to the stepped roll 50 so that the step 51a of the stepped roll 50 contacts the boundary portion 12d of the uncoated portion 12a with the active material layer 14. In this embodiment, the stepped roll 50 has a thicker portion that contacts the uncoated portion 12a. Therefore, in the stepped roll pressing step S6c, the uncoated portion 12a that has already been stretched in the first pressing step S6a is supported by the stepped roll 50.
[0034] <Electrode sheet manufacturing equipment 1> 4, an electrode sheet manufacturing apparatus 1 that embodies such an electrode sheet manufacturing method includes a roll press unit 100 that roll-presses a strip-shaped electrode sheet 10. The roll press unit 100 includes a conveying device 102, a first press device 104, a stepped roll pressing device 108, and a second press device 106.
[0035] <Conveyance device 102> The conveying device 102 is a device that conveys the electrode sheet 10 along a predetermined conveying path W1. Details of the conveying device 102 will be omitted, but it is preferable that the conveying device 102 is a device that conveys the electrode sheet 10 along the conveying path W1. Although not shown in the figures, the conveying device 102 may include a mechanism that feeds the electrode sheet 10 along the conveying path W1, guide rolls that feed the electrode sheet 10 along the conveying path W1, a tension adjustment mechanism that applies a required tension to the electrode sheet 10, and a mechanism that winds up the electrode sheet 10 that has been conveyed along the conveying path W1.
[0036] <First press device 104> As described above, the first press device 104 preferably uses an EPS device with a rubber roll 30. In the EPS device, the position and pressing force of the rubber roll 30 are preferably adjusted so that the uncoated portion 12a is pressed by the rubber roll 30. In addition, the EPS device may be provided with a position adjustment device (not shown) that adjusts the position of the electrode sheet 10 being transported toward the EPS device so that the position of the uncoated portion 12a is aligned with the rubber roll 30 of the EPS device.
[0037] <Stepped roll pressing device 108> The stepped roll pressing device 108 is disposed on the conveying path W1 and presses the stepped roll 50 against the electrode sheet 10. A specific example of the shape of the stepped roll 50 is as described above. As shown in FIG. 6 , the stepped roll pressing device 108 has a step 51a formed to match the boundary 12d between the active material layer 14 and the uncoated portion 12a of the electrode sheet 10. Furthermore, the diameter of the portion 52 that corresponds to the uncoated portion 12a is larger than the diameter of the portion 53 that corresponds to the active material layer 14. The stepped roll pressing device 108 adjusts the position of the electrode sheet 10 and conveys it so that the boundary 12d between the active material layer 14 and the uncoated portion 12a is aligned with the step 51a of the stepped roll 50. For this reason, it is preferable to provide a position adjustment device (not shown) before the stepped roll 50 that adjusts the position of the electrode sheet 10.
[0038] In this manner, in the stepped roll pressing device 108, the electrode sheet 10 is conveyed while the portion 51 provided with the step 51a of the stepped roll 50 is pressed against the boundary portion 12d of the uncoated portion 12a of the electrode sheet 10 where the uncoated portion 12a meets the active material layer 14. Here, the stepped roll pressing device 108 is disposed downstream of the first pressing device 104 (first pressing step S6a) that stretches the uncoated portion 12a. After the uncoated portion 12a of the electrode sheet 10 is stretched, the boundary portion 12d of the uncoated portion 12a of the electrode sheet 10 where the uncoated portion 12a meets the active material layer 14 is stretched by the step 51a of the stepped roll 50. Furthermore, the diameter of the stepped roll 50 at the portion 52 that contacts the uncoated portion 12a is larger than the diameter of the portion 53 that contacts the active material layer 14.
[0039] Therefore, with the uncoated portion 12a and the active material layer 14 already stretched by the first press device 104 appropriately supported by the stepped roll 50, the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is pressed against the step 51a of the stepped roll 50 and straightened. This makes it less likely that the electrode sheet 10 will break when pressed against the stepped roll 50. Furthermore, after the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is stretched by the stepped roll pressing device 108, the coated portion 12b of the electrode sheet 10 is then roll-pressed by the second press device 106 (second press step S6b). In this way, the current collector 12 of the electrode sheet 10 is stretched in the order of the uncoated portion 12a, the boundary portion 12d of the uncoated portion 12a with the active material layer 14, and the coated portion 12b, starting from the outside in the width direction. Therefore, the electrode sheet 10 as a whole is less likely to tear or wrinkle.
[0040] Here, the process of stretching the uncoated portion 12a (first press step S6a) may be a process using, for example, EPS, as described above. As described above, it is difficult to stretch the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 using EPS. In the electrode sheet manufacturing method and electrode sheet manufacturing apparatus 1 proposed here, the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is stretched by the stepped roll 50. Therefore, in the second press step S6b, the coated portion 12b is roll-pressed while the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is stretched. In this case, when the coated portion 12b is roll-pressed, wrinkles are less likely to occur in the boundary portion 12d of the uncoated portion 12a with the active material layer 14 and in the uncoated portion 12a. As a result, wrinkles are suppressed in the electrode sheet 10 as a whole.
[0041] Furthermore, as shown in Figures 3 and 6, the boundary portion 12d is pressed against the step 51a of the stepped roll 50 and stretched, so that even if a protective layer 12c is present at the boundary portion 12d between the uncoated portion 12a and the active material layer 14, the uncoated portion 12a is stretched appropriately.
[0042] The electrode sheet 10 produced by this electrode sheet production method is generally less prone to wrinkles. This electrode sheet production method is preferably used in the production of batteries.
[0043] The invention disclosed herein has been described in various ways. Unless otherwise specified, the embodiments described herein do not limit the present invention. Furthermore, the embodiments of the invention disclosed herein can be modified in various ways, and each component and each process described herein can be omitted or combined as appropriate, unless a particular problem arises.
[0044] As described above, this specification includes the disclosures set forth in the following sections.
[0045] Section 1: 1. A manufacturing apparatus for manufacturing an electrode sheet having a current collector made of a long metal foil, an unformed portion set along a length direction of the current collector at a predetermined position in a width direction thereof, and an active material layer formed on a portion of the current collector excluding the unformed portion, a roll press unit that roll-presses the electrode sheet, The roll press unit is a conveying device that conveys the electrode sheet along a predetermined conveying path; a first press device that is disposed on the transport path and that presses and stretches an unformed portion of the electrode sheet with a rubber roll; a stepped roll pressing device that is disposed on the conveying path downstream of the first press device and presses a stepped roll against the electrode sheet; a second press device that is disposed on the transport path downstream of the stepped roll transport section and that presses and stretches the active material layer of the electrode sheet with a roll press; Equipped with the stepped roll has a step at a portion of the unformed portion that corresponds to a boundary with the active material layer, and the diameter of the portion that corresponds to the unformed portion is larger than the diameter of the portion that corresponds to the active material layer; Electrode sheet manufacturing equipment.
[0046] Section 2: The electrode sheet has a protective layer along the boundary between the active material layer and the unformed portion. Item 1. An electrode sheet manufacturing apparatus according to item 1.
[0047] Section 3: a current collector made of a long metal foil; an unformed portion set along a length direction at a predetermined position in a width direction of the current collector; an active material layer formed on a portion of the current collector excluding the unformed portion; A method for manufacturing an electrode sheet, comprising: a first pressing step of pressing and stretching an unformed portion of the electrode sheet with a rubber roll while transporting the electrode sheet along a predetermined transport path; a stepped roll pressing step of, after the first pressing step, conveying the electrode sheet while pressing it against a stepped roll having a step at a portion of the unformed portion that corresponds to a boundary with the active material layer, the step having a diameter larger than that of a portion of the unformed portion that corresponds to the active material layer; a second pressing step of pressing and stretching the active material layer of the electrode sheet with a roll press after the stepped roll pressing step; A method for manufacturing an electrode sheet, comprising:
[0048] Section 4: The electrode sheet has a protective layer formed along the boundary between the active material layer and an unformed portion. Item 3. A method for producing an electrode sheet according to item 3.
[0049] Section 5: A method for manufacturing a battery comprising the method described in item 3 or 4. [Explanation of symbols]
[0050] 1. Electrode sheet manufacturing equipment 10 Electrode sheet 12 Current collector 12a Uncoated area (unformed area) 12b Coating Department 12c protective layer 12d Boundary part 14 Active material layer 30 rubber roll 31 axes 32 Elastic Body 41,42 Rolls 50,50A stepped roll 51: a portion of the uncoated portion 12a that corresponds to the boundary portion 12d with the active material layer 14 51a Step 51a1 Slope 52: Part corresponding to the active material layer 14 53 Uncoated part 12a 56,57 Guide roll 100 Roll Press Unit 102 Transport device 104 First Press Device 106 Second press device 108 Stepped roll pressing device S1 Transport process S2 Weighing process S3 kneading process S4 Coating process S5 Drying process S6 Roll press process S6a: First pressing step (step of stretching the uncoated portion 12a of the electrode sheet 10) S6b Second pressing step (step of roll-pressing the active material layer 14 of the electrode sheet 10) S6c: Stepped roll pressing step (step of stretching the current collector 12 at the boundary portion 12d) W1 transport route
Claims
1. 1. A manufacturing apparatus for manufacturing an electrode sheet having a current collector made of a long metal foil, an unformed portion set along a length direction of the current collector at a predetermined position in a width direction thereof, and an active material layer formed on a portion of the current collector excluding the unformed portion, a roll press unit that roll-presses the electrode sheet, The roll press unit is a conveying device that conveys the electrode sheet along a predetermined conveying path; a first press device disposed on the transport path and configured to press and stretch an unformed portion of the electrode sheet with a rubber roll; a stepped roll pressing device that is disposed on the transport path and presses a stepped roll against the electrode sheet; a second press device that is disposed on the transport path downstream of the stepped roll transport section and that presses and stretches the active material layer of the electrode sheet with a roll press; Equipped with the stepped roll has a step at a portion of the unformed portion that corresponds to a boundary with the active material layer, and the diameter of the portion that corresponds to the unformed portion is larger than the diameter of the portion that corresponds to the active material layer; Electrode sheet manufacturing equipment.
2. The electrode sheet has a protective layer along the boundary between the active material layer and the unformed portion. The electrode sheet manufacturing device according to claim 1 .
3. a current collector made of a long metal foil; an unformed portion set along a length direction at a predetermined position in a width direction of the current collector; an active material layer formed on a portion of the current collector excluding the unformed portion; A method for manufacturing an electrode sheet, comprising: a first pressing step of pressing and stretching an unformed portion of the electrode sheet with a rubber roll while transporting the electrode sheet along a predetermined transport path; a stepped roll pressing step of, after the first pressing step, conveying the electrode sheet while pressing it against a stepped roll having a step at a portion of the unformed portion that corresponds to a boundary with the active material layer, the step having a diameter larger than that of a portion of the unformed portion that corresponds to the active material layer; a second pressing step of pressing and stretching the active material layer of the electrode sheet with a roll press after the stepped roll pressing step; A method for manufacturing an electrode sheet, comprising:
4. The electrode sheet has a protective layer formed along the boundary between the active material layer and an unformed portion. A method for producing the electrode sheet according to claim 3.
5. A method for manufacturing a battery, comprising the method according to claim 3 or 4.
Citation Information
Patent Citations
Manufacturing method of electrode
JP2023036089A