Electrode sheet manufacturing apparatus and electrode sheet manufacturing method

Abstract

The invention relates to an electrode sheet manufacturing apparatus and an electrode sheet manufacturing method. The present invention addresses the problem of suppressing wrinkles generated in an electrode sheet. This method for manufacturing an electrode sheet (10) is provided with a step roll pressing step in which the electrode sheet (10) is conveyed while being pressed against a step roll (50), and the electrode sheet (10) is pressed against the step roll (50). The diameter of a portion (51) of the step roller (50) that contacts a boundary portion (12d) with the active material layer (14) in the uncoated portion (12a) is locally larger than the diameter of portions (52, 53) that contact other portions (12a, 12b) of the electrode sheet (10).

Description

Technical Field

[0001] This invention relates to an electrode manufacturing apparatus and a method for manufacturing electrode sheets. Background Technology

[0002] Japanese Patent Application Publication No. 2023-36089 discloses a method for manufacturing an electrode sheet. This electrode sheet has a coated portion on a metal foil, coated with an active material layer containing electrode material, and an uncoated portion is provided at the end of the coated portion. In the manufacturing method disclosed in the same publication, the uncoated portion is pressed using a pair of elastic rollers during the rolling of the electrode sheet. By using the pair of elastic rollers to press the uncoated portion, compressive and deformable forces are applied to the same area of ​​the uncoated portion. This allows the uncoated portion to extend while simultaneously preventing breakage.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2023-36089

[0004] Furthermore, the inventors discovered that even when the uncoated portion is pressed by a pair of elastic rollers during the rolling of the electrode sheet, wrinkles still occur on the electrode sheet. Summary of the Invention

[0005] The electrode sheet manufacturing apparatus disclosed herein is an apparatus for manufacturing electrode sheets, which include: a current collector composed of a strip of metal foil; an unformed portion positioned along the length direction at a predetermined position in the width direction of the current collector; and an active material layer formed in the current collector at the portion excluding the unformed portion. The electrode sheet manufacturing apparatus includes a rolling unit for rolling the electrode sheet. The rolling unit includes: a conveying device for conveying the electrode sheet along a predetermined conveying path; and a stepped roller pressing device disposed on the conveying path for pressing the stepped roller onto the electrode sheet. The diameter of the portion of the stepped roller that contacts the boundary between the unformed portion and the active material layer is locally larger than the diameter of the portion that contacts other portions of the electrode sheet.

[0006] According to this electrode sheet manufacturing apparatus, it is possible to suppress wrinkles in the electrode sheet caused by the difference in elongation between the boundary portion of the unformed portion and the active material layer and the current collector in other portions.

[0007] Regarding the electrode sheet manufacturing method disclosed herein, the electrode sheet comprises: a current collector, which is composed of a strip of metal foil; an unformed portion, which is set at a predetermined position in the width direction of the current collector along its length direction; and an active material layer, which is formed in the current collector at the portion other than the unformed portion. A stepped roller pressing process is included, in which the electrode sheet is pressed against a stepped roller while being transported, and the diameter of the portion of the stepped roller that contacts the boundary between the unformed portion and the active material layer is locally larger than the diameter of the portion that contacts other parts of the electrode sheet.

[0008] According to the manufacturing method of this electrode sheet, it is possible to provide an electrode sheet that suppresses wrinkles caused by the difference in elongation between the boundary portion of the unformed portion and the active material layer and the current collector in other portions. Attached Figure Description

[0009] Figure 1 This is a flowchart of the manufacturing process for the electrode sheet.

[0010] Figure 2 This is a schematic diagram of electrode 10.

[0011] Figure 3 This is a schematic diagram showing another way of representing electrode sheet 10.

[0012] Figure 4 This is a schematic diagram illustrating an example of the rolling process S6 presented here.

[0013] Figure 5 This is a schematic diagram of the first pressurization process S6a.

[0014] Figure 6 This is a schematic diagram of the stepped roller pressing process S6c.

[0015] Figure 7 This is a schematic diagram illustrating another method of manufacturing an electrode sheet.

[0016] Figure 8 This is a schematic diagram illustrating another method of manufacturing the electrode sheet 10.

[0017] Figure 9 This is a schematic diagram representing the stepped roller 50A.

[0018] Explanation of reference numerals in the attached figures

[0019] 1…Electrode sheet manufacturing apparatus; 10…Electrode sheet; 12…Current collector; 12a…Uncoated portion (unformed portion); 12b…Coated portion; 12c…Protective layer; 12d…Boundary portion; 14…Active material layer; 30…Rubber roller; 31…Shaft; 32…Elastomer; 41, 42…Rollers; 50, 50A…Stepped rollers; 51…Part that contacts the boundary portion 12d of the uncoated portion 12a with the active material layer 14; 51a…Axial center of portion 51; 52…Part that contacts the active material layer 14; 53…Part that contacts the uncoated portion 12a; 56, 57…Guide rollers; 10 0… Roller pressing unit; 102… Transport device; 104… First pressing device; 106… Second pressing device; 108… Stepped roller pressing device; S1… Transport process; S2… Metering process; S3… Mixing process; S4… Coating process; S5… Drying process; S6… Roller pressing process; S6a… First pressing process (process of elongating the uncoated portion 12a in the electrode sheet 10); S6b… Second pressing process (process of rolling the active material layer 14 in the electrode sheet 10); S6c… Stepped roller pressing process (process of elongating the current collector 12 in the boundary portion 12d); W1… Transport path. Detailed Implementation

[0020] Hereinafter, an embodiment of the technology disclosed herein will be described with reference to the accompanying drawings. The embodiments described herein are not intended to specifically limit the invention. The drawings are schematic depictions and do not necessarily reflect actual objects. Furthermore, components and parts that perform the same function are appropriately labeled with the same reference numerals, and repeated descriptions are appropriately omitted. Unless otherwise specified, expressions such as "X to Y" indicating numerical ranges in this specification mean "X or more, Y or less".

[0021] Figure 1 This is a flowchart of the manufacturing process for the electrode sheet. For example... Figure 1 As shown, the method for manufacturing an electrode sheet includes a handling process S1, a metering process S2, a mixing process S3, a coating process S4, a drying process S5, and a rolling process S6. However, the method for manufacturing an electrode sheet may also include other processes.

[0022] <Electrode Plate 10>

[0023] Figure 2 This is a schematic diagram of electrode plate 10. Electrode plate 10 constitutes the positive or negative electrode plate of the electrode body housed inside the energy storage device. Energy storage device refers to a device that can be repeatedly charged and discharged. In addition to so-called storage batteries (i.e., chemical batteries) such as lithium-ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries, it also includes capacitors (i.e., physical batteries) such as electric double-layer capacitors.

[0024] like Figure 2As shown, the electrode sheet 10 includes a current collector 12 and an active material layer 14. The current collector 12 is a component made of metal foil. The current collector 12 is a long strip-shaped metal component. As the current collector 12, a metal material with the required conductivity can be used. As the positive electrode current collector foil, for example, aluminum, aluminum alloy, etc., can be used. As the negative electrode current collector foil, for example, copper, copper alloy, etc., can be used. The active material layer 14 is applied to a predetermined position in the current collector 12. The active material layer 14 is formed on at least one side of the strip-shaped current collector 12. In this embodiment, the active material layer 14 is formed on both sides of the current collector 12. The active material layer 14 is a layer containing electrode active material. As the positive electrode active material, for example, a lithium transition metal composite oxide can be used. As the negative electrode active material, for example, carbon materials, silicon-based materials, and their mixed oxides can be used. The active material layer may also contain additives other than the electrode active material, such as binders and conductive materials.

[0025] An electrode composite material slurry, forming an active material layer 14, is applied to the current collector 12 and dried to form an electrode sheet 10. The current collector 12 has uncoated portions 12a (unformed portions) and coated portions 12b. The uncoated portions 12a are the parts of the current collector 12 where the active material layer 14 is not coated. The uncoated portions 12a are located at the ends of the electrode sheet 10 in the width direction and extend along the length direction. In this embodiment, the uncoated portions 12a are located at both ends of the electrode sheet 10 in the width direction. The coated portions 12b are disposed between the uncoated portions 12a at both ends of the electrode sheet 10. The electrode composite material slurry is applied to the coated portions 12b. Thus, 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 disposed between the uncoated portions 12a at both ends of the electrode sheet 10 in the width direction. Thus, the electrode sheet may have a current collector 12 made of a long strip of metal foil, an unformed portion (here, an uncoated portion 12a) set at a predetermined position in the width direction along the length direction in the current collector 12, and an active material layer 14 formed in the current collector 12 in the portion other than the unformed portion.

[0026] Figure 3 This is a schematic diagram illustrating another embodiment of electrode 10. (For example...) Figure 3As shown, an insulating protective layer 12c can be provided in the electrode sheet 10 at a position adjacent to the coated portion 12b in the uncoated portion 12a. This structure can be used, for example, in the electrode sheet 10 used for the positive electrode. By providing this protective layer 12c in the electrode sheet 10 used for the positive electrode, short circuits between the positive electrode current collector foil and the negative electrode active material layer can be prevented. This protective layer 12c contains an insulating inorganic filler. Examples of inorganic fillers include insulating particles, such as ceramic particles like alumina. The protective layer 12c may also contain an adhesive, for example. The adhesive may also be included in the positive electrode active material layer and is the same as the illustrated adhesive. Hereinafter, unless otherwise specifically mentioned, reference will be made to the constituent elements of the electrode sheet 10. Figure 2 and Figure 3 .

[0027] <Transportation process S1, Metering process S2, Mixing process S3, Coating process S4, Drying process S5>

[0028] exist Figure 1 In the transport process S1 shown, electrode sheet 10 is transported. In transport process S1, electrode sheet 10 is transported along a predetermined transport path W1. In the metering process S2, the active material layer 14 (see reference) is metered. Figure 2 The raw material is used for the active material layer 14. This measurement can be achieved, for example, by a balance or a metering device (not shown) with a pressure measuring element. The measured raw material of the active material layer 14 is mixed in the mixing step S3. The mixing step S3 can be achieved by a mixing device (not shown). In the coating step S4, the raw material of the active material layer 14, which has become a slurry after being mixed by the mixing device, is coated onto the current collector 12 (see reference). Figure 2 The coating process S4 can be performed, for example, by a slit coater, gravure coater, die coater, comma coater, or other coating apparatus (not shown). In the drying process S5, the raw material of the coated slurry-like active substance layer 14 is dried. The drying process S5 can be performed, for example, by a drying apparatus (not shown) that emits hot air or infrared radiation.

[0029] <Rolling process S6>

[0030] Rolling process S6 is a process of rolling the electrode sheet 10. Here, the substrate of the electrode sheet 10 is a metal foil. In the electrode sheet 10, there are areas where the active material layer 14 is formed (coated area 12b) and areas where the active material layer 14 is not formed (uncoated area 12a). The main purpose of rolling process S6 is to adjust the density of the active material layer 14 formed by coating to an appropriate level.

[0031] In the rolling process S6, the coating section 12b is rolled to achieve an appropriate density for the active material layer 14. If the coating section 12b is rolled, the current collector 12 of the substrate elongates in the coating section 12b, but in the uncoated section 12a, where the pressure is not directly transmitted, the current collector 12 of the substrate does not easily elongate. Therefore, if only the coating section 12b is under pressure, the elongation of the current collector 12 may deviate between the coating section 12b and the uncoated section 12a. If the deviation in the elongation of the current collector 12 between the coating section 12b and the uncoated section 12a is large, it may cause wrinkles to form on the electrode sheet 10. In a subsequent process, the uncoated section 12a is cut into a specified shape to form an electrode tab. At this time, if wrinkles form at the boundary portion 12d of the uncoated section 12a with the active material layer 14, the electrode tab may not be formed into an appropriate shape.

[0032] To prevent wrinkles from forming on the electrode sheet 10, the current collector 12 can be elongated in the uncoated portion 12a before or after rolling the coated portion 12b. One technique for elongating the current collector 12 in the uncoated portion 12a is to press the uncoated portion 12a with a rubber roller. This technique is appropriately called EPS (Elasticity Powered Stretching). Furthermore, the device for pressing the uncoated portion 12a with a rubber roller can be appropriately called an EPS device.

[0033] Furthermore, the inventors have discovered that even when the uncoated portion 12a is stretched using EPS before and after rolling, wrinkles still occur on the electrode sheet 10. These wrinkles particularly occur at the boundary portion 12d of the uncoated portion 12a with the active material layer 14. The inventors have found that this phenomenon is caused by the boundary portion 12d of the uncoated portion 12a with the active material layer 14 not being stretched appropriately when the uncoated portion 12a is stretched using EPS.

[0034] 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. If the rubber roller of the EPS is pressed against the active material layer 14, the active material layer 14 will peel off. From this point of view, in the EPS, the position of the rubber roller is set so that the rubber roller does not contact the coated portion 12b. As a result, in the EPS, it is not easy for the boundary between the uncoated portion 12a and the coated portion 12b and its vicinity to elongate. In addition, sometimes a protective layer containing inorganic fillers is formed at the boundary between the uncoated portion 12a and the coated portion 12b. When a protective layer is formed, when the rubber roller of the EPS is pressed, the elongation rate is sometimes inconsistent between the area where the protective layer is formed and the area where the protective layer is not formed.

[0035] Thus, when the uncoated portion 12a is stretched in the EPS, it is difficult to stretch the boundary portion 12d of the uncoated portion 12a with the active material layer 14 properly. The inventors believe that this will lead to residual deformation in the boundary portion 12d, thereby causing wrinkles in the electrode sheet.

[0036] Figure 4 This is a schematic diagram illustrating an example of the rolling process S6 presented here. For example... Figure 4 As shown, the rolling process S6 includes a first pressing process S6a, a second pressing process S6b, and a stepped roller pressing process S6c.

[0037] The first pressurization step S6a is the aforementioned EPS, which is a step to elongate the uncoated portion 12a in the electrode sheet 10. Figure 5 This is a schematic diagram of the first pressurization step S6a. (See diagram below.) Figure 5 As shown, the first pressurization process S6a is a process in which the electrode sheet 10 is transported along a predetermined transport path while the uncoated portion 12a of the electrode sheet 10 is calendered with a pair of rubber rollers 30.

[0038] like Figure 5 As shown, the rubber roller 30 is simply a roller component with an elastomer 32 disposed on the outer peripheral surface of the shaft 31. The elastomer 32 used for the rubber roller 30 can be an elastic material having the required Young's modulus. Examples of elastomers 32 include rubber, polyurethane, and other resins. In the first pressing step S6a, the uncoated portion 12a is pressed by the rubber roller 30, and is subjected to the reaction force of the elastic deformation and compressive deformation of the rubber roller, thus being pressed and stretched. In the first pressing step S6a, the uncoated portion 12a can be elongated without applying a large tension to the electrode sheet 10.

[0039] like Figure 4 As shown, the second pressing step S6b is a process of rolling the active material layer 14 (coating portion 12b) in the electrode sheet 10. This process adjusts the active material layer 14 (coating portion 12b) to the required density. In the second pressing step S6b, as... Figure 4 As shown, the electrode sheet 10 is held by a pair of rollers 41 and 42, compressing the active material layer 14. At this time, the current collector 12, which serves as the substrate, is calendered at the location where the active material layer 14 is formed (coating portion 12b).

[0040] The stepped roller pressing process S6c is performed on the boundary portion 12d between the uncoated portion 12a and the active material layer 14 (see reference). Figure 2 , Figure 3 The process of locally elongating the current collector 12, which is a substrate. Figure 6 This is a schematic diagram of the stepped roller pressing process S6c.

[0041] <Stepped roller 50>

[0042] In the stepped roller 50 used in process S6c, such as Figure 6 As shown, the diameter of the portion 51 that contacts the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is locally larger than the diameters of other portions (the portion 53 that contacts the active material layer 14, and the portion 52 that contacts the uncoated portion 12a). Figure 6 In the manner shown, the portion 51 that contacts the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is continuous in the circumferential direction and has the same diameter. For example... Figure 4 As shown, the electrode sheet 10 is wound around the stepped roller 50 with the required tension while the stepped roller 50 is being transported. This presses the boundary portion 12d between the active material layer 14 and the uncoated portion 12a against the larger diameter portion 51 of the stepped roller 50. Consequently, the current collector 12 is locally elongated at the boundary portion 12d between the uncoated portion 12a and the active material layer 14. Here, the boundary portion 12d between the uncoated portion 12a and the active material layer 14 can be the boundary between the active material layer 14 and the uncoated portion 12a of the electrode sheet 10, and the area near the boundary.

[0043] Here, the boundary portion 12d between the active material layer 14 and the uncoated portion 12a is defined as the portion of the current collector 12, which serves as the substrate, that is not easily elongated during the first pressing step S6a of calendering the uncoated portion 12a and the second pressing step S6b of rolling the active material layer 14. The boundary portion 12d between the active material layer 14 and the uncoated portion 12a can be determined according to 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 can be, for example, approximately 0 to 3 mm (e.g., approximately 2 mm). Figure 3 As shown, a protective layer 12c may also be formed at the boundary 12d between the active material layer 14 and the uncoated portion 12a.

[0044] According to the rolling process S6, as described above, it includes a stepped roller pressing process S6c. In the stepped roller pressing process S6c, the electrode sheet 10 is pressed against a stepped roller 50 whose diameter is locally larger than the diameter of the portion 51 that contacts the boundary portion 12d of the uncoated portion 12a with the active material layer 14 than the diameter of the portion that contacts other portions of the electrode sheet 10, while the electrode sheet 10 is being transported. Through this stepped roller pressing process S6c, the current collector 12 in the electrode sheet 10 is elongated at the boundary portion 12d of the uncoated portion 12a with the active material layer 14. In addition to the stepped roller pressing process S6c described above, a process to elongate the uncoated portion 12a (first pressing process S6a) and a process to roll the coated portion 12b of the electrode sheet 10 (second pressing process S6b) are also performed. Therefore, the difference in elongation of the current collector 12 can be suppressed at the boundary portion 12d with the active material layer 14 in the uncoated portion 12a and other portions. As a result, wrinkles on the electrode sheet 10 caused by the difference in elongation of the current collector 12 at the boundary portion 12d with the active material layer 14 in the uncoated portion 12a and other portions can be suppressed. In particular, wrinkles generated at the boundary portion 12d with the active material layer 14 in the uncoated portion 12a can be suppressed.

[0045] <Electrode manufacturing apparatus 1>

[0046] like Figure 4 As shown, the electrode sheet manufacturing apparatus 1, which embodies the method for manufacturing the electrode sheet, includes a rolling unit 100 for rolling the strip-shaped electrode sheet 10. The rolling unit 100 includes a conveying device 102, a first pressing device 104, a second pressing device 106, and a stepped roller pressing device 108.

[0047] <Transportation Device 102>

[0048] The conveying device 102 is a device that conveys the electrode sheet 10 along a predetermined conveying path W1. A detailed description of the conveying device 102 is omitted; it is sufficient to refer to any device that conveys the electrode sheet 10 along the conveying path W1. Illustrations of the specific structure are omitted; the conveying device 102 only needs to include a mechanism for feeding the electrode sheet 10 along the conveying path W1, a guide roller for conveying the electrode sheet 10 along the conveying path W1, a tension adjustment mechanism for applying the required tension to the electrode sheet 10, and a mechanism for winding the electrode sheet 10 conveyed along the conveying path W1.

[0049] <Stepped roller pressing device 108>

[0050] The stepped roller pressing device 108 is a device disposed on the transport path W1 and presses the stepped roller 50 onto the electrode sheet 10. For example... Figure 6As shown, the diameter of the portion 51 in the stepped roller 50 that contacts the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is locally larger than the diameter of the portion that contacts other portions of the electrode sheet 10. Figure 4 As shown, the rolling unit 100 includes a first pressing device 104 for rolling the uncoated portion 12a of the electrode sheet 10 with a rubber roller 30. Furthermore, the rolling unit 100 includes a second pressing device 106, which is disposed downstream of the first pressing device 104 in the transport path W1, and rolls the active material layer 14 of the electrode sheet 10 by rolling. Figure 4 The arrow marked with reference numeral W1 in the attached diagram indicates the direction of transport along the transport path W1.

[0051] In the stepped roller pressing device 108, such as Figure 6 As shown, a stepped roller 50 is provided, and for this stepped roller 50, the diameter of the portion 51 that contacts the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is locally larger than the diameter of the portion that contacts other portions of the electrode sheet 10. In the electrode sheet 10, the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is pressed against the portion 51 of the stepped roller 50 with the locally larger diameter. For example, in Figure 4 In the illustrated configuration, guide rollers 56 and 57 are arranged on the upstream and downstream sides of the stepped roller 50. The electrode sheet 10 is guided by the guide rollers 56 and 57 and wound around the stepped roller 50 while being transported. At this time, tension is applied to the electrode sheet 10 via the guide rollers 56 and 57 in a manner that presses the electrode sheet 10 against the stepped roller 50. At this time, as... Figure 6 As shown, the partially protruding portion 51 of the stepped roller 50 is pressed against the boundary portion 12d of the uncoated portion 12a of the electrode sheet 10 with the active material layer 14.

[0052] In this way, in the stepped roller pressing device 108, the electrode sheet 10 is transported while the partially protruding portion 51 of the stepped roller 50 is pressed against the boundary portion 12d of the uncoated portion 12a of the electrode sheet 10 with the active material layer 14. As a result, the current collector 12 is locally elongated at the boundary portion 12d of the uncoated portion 12a with the active material layer 14. Moreover, in addition to the stepped roller pressing process S6c described above, a process to elongate the uncoated portion 12a (first pressing process S6a) and a process to roll the coated portion 12b of the electrode sheet 10 are also performed (second pressing process S6b). As a result, the difference in elongation of the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 and other portions can be suppressed. As a result, wrinkles on the electrode sheet 10 caused by the difference in elongation between the boundary portion 12d of the uncoated portion 12a and the active material layer 14 and the current collector 12 in other portions can be suppressed. In particular, wrinkles generated at the boundary portion 12d of the uncoated portion 12a and the active material layer 14 can be suppressed.

[0053] Here, as described above, the process of elongating the uncoated portion 12a can be based on EPS processing, for example. As mentioned above, in EPS, it is difficult to elongate the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14. In the electrode sheet manufacturing method and electrode sheet manufacturing apparatus 1 presented here, the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is elongated by a stepped roller 50. From this viewpoint, when EPS is used in the process of elongating the uncoated portion 12a, the process of locally elongating the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 by a stepped roller 50, as described above, is particularly advantageous. Furthermore, unless otherwise specifically mentioned, the process of elongating the uncoated portion 12a is not limited to EPS.

[0054] In the electrode sheet manufacturing method presented herein, the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is locally elongated using a stepped roller 50. This local elongation of the current collector 12 at the boundary portion 12d is performed simultaneously with the elongation of the uncoated portion 12a and the rolling process of the coated portion 12b of the electrode sheet 10. Therefore, the difference in elongation of the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 and other portions can be suppressed. The electrode sheet manufacturing method presented herein can be incorporated into a battery manufacturing method.

[0055] like Figure 4As shown, according to the inventor's understanding, the process of elongating the uncoated portion 12a (first pressurization step S6a) can be performed before the process of elongating the coated portion 12b (second pressurization step S6b). If the uncoated portion 12a is elongated before the process of elongating the coated portion 12b (second pressurization step S6b), wrinkles are less likely to occur when the coated portion 12b is elongated. The process of elongating the uncoated portion 12a (first pressurization step S6a) can be performed by EPS as described above.

[0056] exist Figure 4 In the illustrated manner, the stepped roller pressing process S6c is performed after the treatment that elongates the coating portion 12b (the second pressing process S6b). For the electrode sheet manufacturing apparatus 1, as... Figure 4 As shown, the first pressurizing device 104, the second pressurizing device 106, and the stepped roller pressing device 108 are arranged sequentially along the transport direction of the transport path W1.

[0057] In this case, firstly, the uncoated portion 12a is elongated. Then, after the coated portion 12b is elongated, the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is locally elongated by a stepped roller pressing process S6c. In this case, after elongating both the uncoated portion 12a and the coated portion 12b, the deformation remaining locally in the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is corrected by the stepped roller pressing process S6c. As a result, wrinkles on the electrode sheet 10 as a whole are suppressed.

[0058] Figure 7 This is a schematic diagram illustrating another method of manufacturing the electrode sheet. Figure 7 In the illustrated method, a stepped roller pressing process S6c is performed before the further elongation of the uncoated portion 12a (first pressing process S6a). Figure 7 As shown, the electrode sheet manufacturing apparatus 1 is provided with a stepped roller pressing device 108, a first pressing device 104 and a second pressing device 106 arranged sequentially along the transport direction of the transport path W1.

[0059] In this case, through the stepped roller pressing process S6c, firstly, the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is partially elongated. Next, the uncoated portion 12a is elongated, and the coated portion 12b is elongated. In this case, while the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is partially elongated, the uncoated portion 12a is elongated, and the coated portion 12b is elongated. Thus, before processing the uncoated portion 12a and the coated portion 12b, the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is partially elongated. As a result, when the uncoated portion 12a and the coated portion 12b are elongated, wrinkles on the electrode sheet 10 as a whole are suppressed.

[0060] Figure 8 This is a schematic diagram illustrating another method of manufacturing the electrode sheet 10. Figure 8 In the illustrated configuration, a stepped roller pressing process S6c is performed after the first pressing process S6a and before the second pressing process S6b. For example... Figure 8 As shown, the electrode sheet manufacturing apparatus 1 is provided with a first pressing device 104, a stepped roller pressing device 108 and a second pressing device 106 arranged sequentially along the transport direction of the transport path W1.

[0061] In this case, after the uncoated portion 12a is elongated by the first pressing step S6a, the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is partially elongated by the stepped roller pressing step S6c. Furthermore, the coated portion 12b is further elongated by the second pressing step S6b. In this case, after the uncoated portion 12a is elongated by the elongation process, the current collector 12 at the boundary portion 12d of the uncoated portion 12a with the active material layer 14 is partially elongated. Subsequently, the coated portion 12b is elongated. In this case, the electrode sheet 10 is elongated in stages from the outside, and wrinkles on the electrode sheet 10 as a whole are suppressed.

[0062] As described above, in the rolling process S6 of the electrode sheet 10, the order of the process of locally elongating the current collector 12 of the boundary portion 12d, the rolling of the electrode sheet 10, and the process of elongating the uncoated portion 12a can be appropriately changed.

[0063] For example, in Figure 4In the above-mentioned process, the first pressing step S6a (the step of pressing the uncoated portion 12a) is performed before the second pressing step S6b (the step of rolling the active material layer 14), but this order is not limited. The first pressing step S6a can be performed between (i) and the second pressing step S6b, or after (ii) the second pressing step S6b. In addition, the first pressing step S6a can also be performed before or after (iii) the second pressing step S6b. In (i) to (iii), the stepped roller pressing step S6c described above can also be performed at any position, such as upstream or downstream of the first pressing step S6a, or upstream or downstream of the second pressing step S6b.

[0064] <Stepped Roller 50A>

[0065] Figure 9 This is a schematic diagram representing the stepped roller 50A. The stepped roller 50A is another type of stepped roller 50 used in the stepped roller pressing process S6c. Figure 9 In the example shown, for the portion 51 of the stepped roller 50A that contacts the boundary portion 12d of the uncoated portion 12a with the active material layer 14, the protrusion is more pronounced closer to the center portion 51a in the axial direction of the stepped roller 50A. More specifically, in Figure 9 In the example shown, the central portion protrudes symmetrically along the axial direction of the stepped roller 50A, as if distributed normally. Thus, the portion 51 that contacts the boundary portion 12d of the uncoated portion 12a with the active material layer 14 can also be convex towards the center in the width direction. Because the axial central portion is convex, areas with abrupt height changes, such as step differences, disappear in the stepped roller 50A. Therefore, wrinkles on the electrode sheet 10 caused by the locally thickened portion 51 of the stepped roller 50A can be suppressed.

[0066] In this case, the portion 51 is not limited to a shape that protrudes symmetrically in the center as if it were a normal distribution; it can also protrude in an arc shape. The center of the portion 51 of the stepped roller 50A where the diameter is locally thickened can be aligned with the center in the width direction of the portion where the current collector 12 is expected to be under-extended in the first pressing step S6a and the second pressing step S6b. From this point of view, the axial spacing of the portions 51 of the stepped roller 50A where the diameter is locally thickened can be set according to the width of the coating portion 12b of the electrode sheet 10 to be processed. In addition, the electrode sheet 10 is transported relative to the stepped roller 50A so that the position of the portion where the current collector 12 is expected to be under-extended is aligned with the center in the width direction of the portion 51 of the stepped roller 50A where the diameter is locally thickened. From this point of view, a position adjustment mechanism or the like for adjusting the position of the electrode sheet 10 relative to the stepped roller 50 can also be assembled in the transport device 102.

[0067] The invention disclosed herein has been described in various ways above. Unless otherwise specified, the embodiments described herein are not intended to limit the invention. Furthermore, the embodiments of the invention disclosed herein can be modified in various ways, and the constituent elements and processes mentioned herein can be appropriately omitted or combined as long as no particular problems arise.

[0068] As stated above, this specification includes the disclosures described below.

[0069] Item 1:

[0070] An electrode sheet manufacturing apparatus is provided for manufacturing electrode sheets, the electrode sheet comprising: a current collector composed of a strip of metal foil; an unformed portion set at a predetermined position in the width direction of the current collector along its length direction; and an active material layer formed in the current collector at a portion other than the unformed portion. The electrode sheet manufacturing apparatus includes a rolling unit for rolling the electrode sheet, the rolling unit comprising: a conveying device for conveying the electrode sheet along a predetermined conveying path; and a stepped roller pressing device disposed on the conveying path for pressing the stepped roller onto the electrode sheet, wherein the diameter of the portion of the stepped roller that contacts the boundary between the unformed portion and the active material layer is locally larger than the diameter of the portion that contacts other portions of the electrode sheet.

[0071] Item 2:

[0072] According to the electrode sheet manufacturing apparatus described in item 1, the rolling unit further comprises: a first pressing device disposed in the transport path and rolling the unformed portion of the electrode sheet with a rubber roller; and a second pressing device disposed downstream of the first pressing device in the transport path and rolling the active material layer of the electrode sheet by rolling, wherein the stepped roller pressing device is disposed upstream of the first pressing device in the transport path.

[0073] Item 3:

[0074] According to the electrode sheet manufacturing apparatus described in item 1, the rolling unit further comprises: a first pressing device disposed in the transport path and rolling the unformed portion of the electrode sheet with a rubber roller; and a second pressing device disposed downstream of the first pressing device in the transport path and rolling the active material layer of the electrode sheet by rolling, wherein the stepped roller pressing device is disposed downstream of the first pressing device and upstream of the second pressing device in the transport path.

[0075] Item 4:

[0076] According to the electrode sheet manufacturing apparatus described in item 1, the rolling unit further comprises: a first pressing device disposed in the transport path and rolling the unformed portion of the electrode sheet with a rubber roller; and a second pressing device disposed downstream of the first pressing device in the transport path and rolling the active material layer of the electrode sheet by rolling, wherein the stepped roller pressing device is disposed downstream of the second pressing device in the transport path.

[0077] Item 5:

[0078] According to the electrode sheet manufacturing apparatus described in item 1, the portion of the stepped roller that contacts the boundary portion of the unformed portion with the active material layer protrudes more axially closer to the center.

[0079] Item 6:

[0080] A method for manufacturing an electrode sheet, the electrode sheet comprising: a current collector composed of a strip of metal foil; an unformed portion set at a predetermined position in the width direction of the current collector along its length direction; and an active material layer formed in the current collector at a portion other than the unformed portion, wherein the method for manufacturing the electrode sheet includes a stepped roller pressing step, in which the electrode sheet is pressed against a stepped roller while being transported, wherein the diameter of the portion of the stepped roller that contacts the boundary between the unformed portion and the active material layer is locally larger than the diameter of the portion that contacts other portions of the electrode sheet.

[0081] Item 7:

[0082] According to the electrode sheet manufacturing method described in item 6, the electrode sheet manufacturing method includes: a first pressing step in which the electrode sheet is transported along a predetermined transport path while the unformed portion of the electrode sheet is rolled with a rubber roller; and a second pressing step in which the active material layer of the electrode sheet is rolled after the first pressing step in the transport path, and the stepped roller pressing step is performed before the first pressing step.

[0083] Item 8:

[0084] According to the electrode sheet manufacturing method described in item 6, the electrode sheet manufacturing method includes: a first pressing step in which the electrode sheet is transported along a predetermined transport path while the unformed portion of the electrode sheet is rolled with a rubber roller; and a second pressing step in which, after the first pressing step in the transport path, the active material layer in the electrode sheet is rolled by roller pressing, and the stepped roller pressing step is performed after the first pressing step and before the second pressing step.

[0085] Item 9:

[0086] According to the electrode sheet manufacturing method described in item 6, the electrode sheet manufacturing method includes: a first pressing step in which the electrode sheet is transported along a predetermined transport path while the unformed portion of the electrode sheet is rolled with a rubber roller; and a second pressing step in which, after the first pressing step in the transport path, the active material layer in the electrode sheet is rolled, and after the second pressing step, the stepped roller pressing step is performed.

[0087] Item 10:

[0088] According to the electrode sheet manufacturing method described in item 6, the portion of the stepped roller that contacts the boundary portion of the unformed portion with the active material layer protrudes more axially closer to the center.

[0089] Item 11:

[0090] A method for manufacturing a battery, wherein the method comprises manufacturing an electrode sheet as described in any one of claims 6 to 10.

Claims

1. An electrode sheet manufacturing apparatus, comprising: a current collector composed of a strip of metal foil; an unformed portion disposed along the length direction at a predetermined position in the width direction of the current collector; and an active material layer formed in the current collector excluding the unformed portion, wherein... The electrode sheet manufacturing apparatus includes a rolling unit for rolling the electrode sheet. The roller pressing unit includes: The transport device transports the electrode sheet along a pre-determined transport path; and A stepped roller pressing device is disposed in the conveying path and presses the stepped roller onto the electrode sheet. The diameter of the portion of the stepped roller that contacts the boundary between the unformed portion and the active material layer is locally larger than the diameter of the portion that contacts other parts of the electrode sheet.

2. The electrode sheet manufacturing apparatus according to claim 1, wherein, The roller pressing unit also includes: A first pressurizing device is disposed in the transport path and uses a rubber roller to calculate the unformed portions in the electrode sheet; and The second pressurizing device is located downstream of the first pressurizing device in the transport path, and rolls the active material layer in the electrode sheet by a rolling process. The stepped roller pressing device is positioned upstream of the first pressing device in the transport path.

3. The electrode sheet manufacturing apparatus according to claim 1, wherein, The roller pressing unit also includes: A first pressurizing device is disposed in the transport path and uses a rubber roller to calculate the unformed portions in the electrode sheet; and The second pressurizing device is located downstream of the first pressurizing device in the transport path, and rolls the active material layer in the electrode sheet by a rolling process. The stepped roller pressing device is located downstream of the first pressing device and upstream of the second pressing device in the transport path.

4. The electrode sheet manufacturing apparatus according to claim 1, wherein, The roller pressing unit also includes: A first pressurizing device is disposed in the transport path and uses a rubber roller to calculate the unformed portions in the electrode sheet; and The second pressurizing device is located downstream of the first pressurizing device in the transport path, and rolls the active material layer in the electrode sheet by a rolling process. The stepped roller pressing device is located downstream of the second pressing device in the transport path.

5. The electrode sheet manufacturing apparatus according to claim 1, wherein, The portion of the stepped roller that contacts the boundary between the unformed portion and the active material layer protrudes more axially towards the center.

6. A method for manufacturing an electrode sheet, wherein the electrode sheet comprises: The current collector is made of long strips of metal foil; The unformed portion is positioned along the length direction at a predetermined position in the width direction of the current collector; and An active material layer is formed in the current collector in the portion other than the unformed portion. in, The method for manufacturing the electrode sheet includes a stepped roller pressing process. In the stepped roller pressing process, the electrode sheet is pressed against the stepped roller while being transported. The diameter of the portion of the stepped roller that contacts the boundary portion of the unformed portion with the active material layer is locally larger than the diameter of the portion that contacts other portions of the electrode sheet.

7. The method for manufacturing the electrode sheet according to claim 6, wherein, The method for manufacturing the electrode sheet includes: In the first pressurization process, the electrode sheet is transported along a pre-determined transport path while the unformed portions of the electrode sheet are rolled using rubber rollers; and The second pressurization step involves rolling the active material layer in the electrode sheet after the first pressurization step in the transport path. The stepped roller pressing process is performed before the first pressing process.

8. The method for manufacturing the electrode sheet according to claim 6, wherein, The method for manufacturing the electrode sheet includes: In the first pressurization process, the electrode sheet is transported along a pre-determined transport path while the unformed portions of the electrode sheet are rolled using rubber rollers; and The second pressurization step involves rolling the active material layer in the electrode sheet after the first pressurization step in the transport path. The stepped roller pressing process is performed after the first pressing process and before the second pressing process.

9. The method for manufacturing an electrode sheet according to claim 6, wherein, The method for manufacturing the electrode sheet includes: In the first pressurization process, the electrode sheet is transported along a pre-determined transport path while the unformed portions of the electrode sheet are rolled using rubber rollers; and The second pressurization step involves rolling the active material layer in the electrode sheet after the first pressurization step in the transport path. The stepped roller pressing process is performed after the second pressing process.

10. The method for manufacturing the electrode sheet according to claim 6, wherein, The portion of the stepped roller that contacts the boundary between the unformed portion and the active material layer protrudes more axially towards the center.

11. A method for manufacturing a battery, wherein, The method comprising any one of claims 6 to 10.

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