Manufacturing device for electrode mixture sheet

Abstract

A manufacturing device 1 for an electrode mixture sheet S comprises a second roll 4 and a third roll 6 that convey the electrode mixture sheet S. The second roll 4 and the third roll 6 transfer the electrode mixture sheet S supported by the second circumferential surface 4a of the second roll 4 and conveyed to a gap between the second roll 4 and the third roll 6 from the second circumferential surface 4a to the third circumferential surface 6a of the third roll 6, and support and convey the electrode mixture sheet S via the third circumferential surface 6a. The arithmetic mean curvature Spc of the peak of the second circumferential surface 4a satisfies the condition 46.2 < Spc < 54.1. The Spc of the third circumferential surface satisfies the condition 48.8 ≤ Spc < 74.0.

Description

Manufacturing Apparatus for Electrode Composite Sheet

[0001] The present disclosure relates to a manufacturing apparatus for an electrode composite sheet.

[0002] Patent Document 1 describes a method for manufacturing a coated film object in which a wet electrode composite paint is introduced into the gap between a first roll and a second roll, and a coating film is formed on the surface of the second roll and conveyed.

[0003] Japanese Unexamined Patent Application Publication No. 2016-59870

[0004] Regarding dry electrode composites, there are cases where they are formed into a sheet shape and conveyed using a plurality of rolls as in the above-described manufacturing method. As a result of intensive studies on a manufacturing apparatus for a dry electrode composite sheet, the inventor has found a technique for improving the performance of the manufacturing apparatus, such as the transportability of the electrode composite sheet.

[0005] The present disclosure has been made in view of such circumstances, and an object thereof is to provide a technique for improving the performance of a manufacturing apparatus for an electrode composite sheet.

[0006] One aspect of the present disclosure is a manufacturing apparatus for an electrode composite sheet. This apparatus includes a second roll and a third roll that are adjacent to each other with a predetermined interval and convey an electrode composite sheet in which a dry electrode composite is compressed into a sheet shape. The electrode composite sheet supported by the second circumferential surface of the second roll and conveyed into the gap between the second roll and the third roll is transferred from the second circumferential surface to the third circumferential surface of the third roll and supported and conveyed by the third circumferential surface. The second circumferential surface satisfies the condition that the arithmetic mean curvature Spc of the peak points measured in accordance with JIS B 0601:2001 standard is 46.2 < Spc < 54.1. The third circumferential surface satisfies the condition that Spc is 48.8 ≤ Spc < 74.0.

[0007] Another aspect of the present disclosure is an apparatus for manufacturing electrode mixture sheets. The apparatus comprises a second roll and a third roll adjacent to each other at a predetermined interval, for conveying an electrode mixture sheet in which a dry electrode mixture has been compressed into a sheet, wherein the second roll and the third roll support the electrode mixture sheet, which is conveyed in the gap between the second roll and the third roll, from the second roll to the third roll, where it is supported and conveyed by the third roll. The second roll satisfies the condition that the aspect ratio Str of the surface properties, measured in accordance with the JIS B 0601:2001 standard, is 0.84 ≤ Str < 0.87. The third roll satisfies the condition that Str is 0.85 ≤ Str < 0.87.

[0008] Another aspect of the present disclosure is an apparatus for manufacturing electrode mixture sheets. The apparatus comprises a second roll and a third roll adjacent to each other at a predetermined interval, for conveying an electrode mixture sheet in which a dry electrode mixture has been compressed into a sheet, wherein the second roll and the third roll transfer the electrode mixture sheet, which is supported by the second circumferential surface of the second roll and conveyed in the gap between the second roll and the third roll, from the second circumferential surface to the third circumferential surface of the third roll, where it is supported and conveyed by the third circumferential surface. The second circumferential surface satisfies the condition that the peak density Spd of the peaks, measured in accordance with the JIS B 0601:2001 standard, is 4005 < Spd < 6429. The third circumferential surface satisfies the condition that Spd is 2585 ≤ Spd < 2981.

[0009] Another aspect of the present disclosure is an apparatus for manufacturing electrode mixture sheets. This apparatus comprises a second roll and a third roll adjacent to each other at a predetermined interval, for conveying an electrode mixture sheet in which a dry electrode mixture has been compressed into a sheet, wherein the second roll and the third roll support the electrode mixture sheet, which is conveyed in the gap between the second roll and the third roll, from the second roll to the third roll, where it is supported and conveyed by the third roll. The third roll satisfies the condition that the root mean square gradient Sdq, measured in accordance with the JIS B 0601:2001 standard, is 0.10 ≤ Sdq < 0.14.

[0010] Any combination of the above components, as well as any conversion of the expressions of this disclosure between methods, apparatus, systems, etc., are also valid forms of this disclosure.

[0011] According to this disclosure, it is possible to improve the performance of the manufacturing apparatus for electrode mixture sheets.

[0012] This is a schematic diagram of a manufacturing apparatus for electrode mixture sheets according to an embodiment. This figure shows the results of a transferability evaluation test.

[0013] The present disclosure will be described below with reference to the drawings, based on preferred embodiments. The embodiments are illustrative and not limiting, and not all features or combinations thereof described in the embodiments are necessarily essential to the present disclosure. The same or equivalent components, members, and processes shown in each drawing are denoted by the same reference numerals, and redundant descriptions are omitted where appropriate. The scale and shape of each part shown in each drawing are set for convenience to facilitate explanation and are not to be interpreted restrictively unless otherwise specified. Furthermore, where terms such as "first," "second," etc. are used in this specification or claims, unless otherwise specified, these terms do not indicate any order or importance, but are used to distinguish one configuration from another. In addition, some components that are not important for explaining the embodiments are omitted in each drawing.

[0014] Figure 1 is a schematic diagram of an electrode mixture sheet manufacturing apparatus 1 according to an embodiment. The electrode mixture sheet manufacturing apparatus 1 comprises a first roll 2, a second roll 4, a third roll 6, and a storage section 8. Hereinafter, the electrode mixture sheet manufacturing apparatus 1 will be abbreviated as "manufacturing apparatus 1" as appropriate. In the manufacturing apparatus 1 of this embodiment, as an example, the first roll 2, the second roll 4, and the third roll 6 are arranged in the horizontal direction.

[0015] The storage section 8 has a known structure, such as a combination of a hopper and a feeder, and stores the dry electrode mixture P, which is the raw material for the electrode mixture sheet S. The dry electrode mixture P contains an electrode active material and a binder. It also contains a conductive agent and a solvent as needed. The binder and solvent function as binding components that bind the electrode active materials together.

[0016] In typical lithium-ion secondary batteries, the electrode active material is lithium cobalt oxide or lithium iron phosphate for the positive electrode, and graphite for the negative electrode. The binder is polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), etc. The conductive agent is graphite, carbon black, acetylene black, etc. When dry electrode mixture P is used as the negative electrode, the solvent is water, alcohols, N-methylpyrrolidone (NMP), toluene, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), etc. When dry electrode mixture P is used as the positive electrode, the solvent is amine-based solvent, ether-based solvent, ketone-based solvent, ester-based solvent, amide-based solvent, etc. As an example, the solvent content of dry electrode mixture P is 5% by mass or less, 3% by mass or less, 0.1% by mass, or substantially 0% of the total mass of dry electrode mixture P.

[0017] A first roll 2 and a second roll 4 are positioned at the powder outlet of the storage section 8. The orientation of the first roll 2 and the second roll 4 is determined so that their respective rotation axes are parallel to each other, and they are adjacent to each other with a predetermined distance between them. The second roll 4 is positioned downstream of the first roll 2 in the direction of conveying the electrode mixture sheet S. Dry electrode mixture P is supplied from the storage section 8 into the gap between the first roll 2 and the second roll 4. In this embodiment, the first roll 2 and the second roll 4 function as feed rolls. That is, the first roll 2 supplies the dry electrode mixture P from the storage section 8 into the gap between the two rolls by placing it on its first circumferential surface 2a. The second roll 4 supplies the dry electrode mixture P from the storage section 8 into the gap between the two rolls by placing it on its second circumferential surface 4a.

[0018] The first roll 2 and the second roll 4 rotate in opposite directions, compressing the dry electrode mixture P supplied into the gap into a sheet. This forms the electrode mixture sheet S. Therefore, the first roll 2 and the second roll 4 also function as forming rolls. The electrode mixture sheet S is continuously fed out from the gap between the first roll 2 and the second roll 4. Therefore, the electrode mixture sheet S is a long strip in the conveying direction. The electrode mixture sheet S is conveyed downstream while being supported by the second circumferential surface 4a of the second roll 4. Therefore, the second roll 4 also functions as a conveying roll.

[0019] A third roll 6 is positioned downstream of the second roll 4. The second roll 4 and the third roll 6 are positioned adjacent to each other with a predetermined distance between them, so that their respective axes of rotation are parallel to each other. The electrode mixture sheet S is supported and conveyed by the second circumferential surface 4a of the second roll 4 and transported into the gap between the second roll 4 and the third roll 6. The second roll 4 and the third roll 6 can feed the electrode mixture sheet S downstream by rotating in opposite directions with the electrode mixture sheet S sandwiched between them. As the electrode mixture sheet S passes through the gap between the second roll 4 and the third roll 6, it is transferred from the second circumferential surface 4a to the third circumferential surface 6a of the third roll 6 at the position where the second roll 4 and the third roll 6 face each other. The electrode mixture sheet S is then supported by the third circumferential surface 6a of the third roll 6 and transported downstream. Therefore, the third roll 6 functions as a transport roll.

[0020] The electrode mixture sheet S may be stretched as it passes through the gap between the second roll 4 and the third roll 6. In other words, the second roll 4 and the third roll 6 may function as stretching rolls. For example, the second roll 4 and the third roll 6 rotate at different peripheral speeds. Specifically, the rotation speed of the third roll 6 is faster than the rotation speed of the second roll 4. This allows the second roll 4 and the third roll 6 to transport the electrode mixture sheet S and stretch it due to the difference in their peripheral speeds. Alternatively, the electrode mixture sheet S can also be stretched by making the gap between the second roll 4 and the third roll 6 narrower than the thickness of the incoming electrode mixture sheet S.

[0021] The second surface 4a satisfies the condition that the arithmetic mean curvature Spc of the peak is 46.2 < Spc < 54.1. The third surface 6a satisfies the condition that Spc is 48.8 ≤ Spc < 74.0. Spc is measured using a contact-type roughness meter in accordance with the JIS B 0601:2001 standard. This allows the friction coefficients of the second surface 4a and the third surface 6a relative to the electrode mixture sheet S to be adjusted to a size suitable for conveying the electrode mixture sheet S. Therefore, the conveyability of the electrode mixture sheet S in the manufacturing apparatus 1 can be improved.

[0022] Furthermore, the second circumferential surface 4a satisfies the condition that the aspect ratio Str of the surface texture is 0.84 ≤ Str < 0.87. Also, the third circumferential surface 6a satisfies the condition that Str is 0.85 ≤ Str < 0.87. Str is measured using a contact-type roughness meter in accordance with the JIS B 0601:2001 standard. This allows the anisotropy of contact between each circumferential surface and the electrode mixture sheet S to be adjusted to a degree suitable for supporting the electrode mixture sheet S. Therefore, the electrode mixture sheet S can be transported more stably on each circumferential surface. Thus, the transportability of the electrode mixture sheet S in the manufacturing apparatus 1 can be improved.

[0023] Furthermore, the second circumferential surface 4a satisfies the condition that the peak density Spd is 4005 < Spd < 6429. Also, the third circumferential surface 6a satisfies the condition that Spd is 2585 ≤ Spd < 2981. Spd is measured using a contact-type roughness meter in accordance with the JIS B 0601:2001 standard. This allows the number of contact points with the electrode mixture sheet S on each circumferential surface to be adjusted to a number suitable for transferring the electrode mixture sheet S from the second circumferential surface 4a to the third circumferential surface 6a while ensuring good adhesion between each circumferential surface and the electrode mixture sheet S. Thus, the transportability of the electrode mixture sheet S in the manufacturing apparatus 1 can be improved. In addition, by satisfying the above condition for Spd of the second circumferential surface 4a, the transferability of the electrode mixture sheet S from the first circumferential surface 2a to the second circumferential surface 4a can also be easily improved.

[0024] Furthermore, the third circumferential surface 6a satisfies the condition that the root mean square gradient Sdq is 0.10 ≤ Sdq < 0.14. Sdq is measured using a contact-type roughness meter in accordance with the JIS B 0601:2001 standard. This allows the adhesion between the third circumferential surface 6a and the electrode mixture sheet S to be adjusted to a degree suitable for transferring the electrode mixture sheet S from the second circumferential surface 4a to the third circumferential surface 6a. Thus, the transportability of the electrode mixture sheet S can be improved.

[0025] Preferably, the second circumferential surface 4a and the third circumferential surface 6a satisfy all of the above conditions for Spc, Str, Spd, and Sdq. This further improves the transportability of the electrode mixture sheet S in the manufacturing apparatus 1.

[0026] The configuration of the manufacturing apparatus 1 can be modified as appropriate. For example, the arrangement direction of the first roll 2, the second roll 4, and the third roll 6 is not particularly limited. For example, the third roll 6 may be arranged vertically or diagonally with respect to the second roll 4. In addition, one or more transport rolls may be arranged downstream of the third roll 6. Furthermore, a lamination roll may be arranged adjacent to the downstream transport roll. In this case, the electrode mixture sheet S can be laminated onto a sheet material such as a current collector plate that is transported by the lamination roll. Also, the storage section 8 may be omitted. In this case, the manufacturing apparatus 1 can be interpreted as a transport device for the electrode mixture sheet S, the second roll 4 can be interpreted as an upstream transport roll having only a transport function, and the third roll 6 can be interpreted as a downstream transport roll having only a transport function.

[0027] The embodiments of this disclosure have been described in detail above. The embodiments described above are merely examples of how to implement this disclosure. The content of the embodiments does not limit the technical scope of this disclosure, and many design changes, such as changes, additions, and deletions of components, are possible, as long as they do not deviate from the idea of ​​this disclosure as defined in the claims. A new embodiment with design changes will have the effects of both the combined embodiment and the variation. In the embodiments described above, the content in which such design changes are possible is emphasized with notations such as "of this embodiment" or "in this embodiment," but design changes are also permitted even if there are no such notations. Any combination of components included in each embodiment is also valid as an embodiment of this disclosure. The hatching applied to the cross-section in the drawings does not limit the material of the object to which the hatching is applied.

[0028] The embodiments may be specified by the items described below. [Item 1] A second roll (4) and a third roll (6) adjacent to each other at a predetermined interval, for transporting an electrode mixture sheet (S) in which a dry electrode mixture (P) is compressed into a sheet, wherein the second roll (4) and the third roll (6) support the electrode mixture sheet (S) which is transported in the gap between the second roll (4) and the third roll (6), and transfer the electrode mixture sheet (S) from the second roll (4a) to the third roll (6a) of the third roll (6) and support and transport it on the third roll (6a), wherein the second roll (4a) satisfies the condition that the arithmetic mean curvature Spc of the peak, measured in accordance with the JIS B 0601:2001 standard, is 46.2 < Spc < 54.1, and the third roll (6a) satisfies the condition that Spc is 48.8 ≤ Spc < 74.0. Manufacturing apparatus (1) for electrode mixture sheet (S). [Item 2] A second roll (4) and a third roll (6) adjacent to each other at a predetermined interval, for transporting an electrode mixture sheet (S) in which a dry electrode mixture (P) is compressed into a sheet, wherein the second roll (4) and the third roll (6) support the electrode mixture sheet (S) which is transported in the gap between the second roll (4) and the third roll (6), and transfer the electrode mixture sheet (S) from the second roll (4a) to the third roll (6a) of the third roll (6) and support and transport it on the third roll (6a), wherein the second roll (4a) satisfies the condition that the aspect ratio Str of the surface properties measured in accordance with the JIS B 0601:2001 standard is 0.84 ≤ Str < 0.87, and the third roll (6a) satisfies the condition that Str is 0.85 ≤ Str < 0.87. Manufacturing apparatus (1) for electrode mixture sheet (S).[Item 3] A second roll (4) and a third roll (6) adjacent to each other at a predetermined interval, for transporting an electrode mixture sheet (S) in which a dry electrode mixture (P) is compressed into a sheet, wherein the second roll (4) and the third roll (6) support the electrode mixture sheet (S) which is transported in the gap between the second roll (4) and the third roll (6), and transfer the electrode mixture sheet (S) from the second roll (4a) to the third roll (6a) of the third roll (6) and support and transport it on the third roll (6a), wherein the second roll (4a) satisfies the condition that the peak density Spd of the mountain, measured in accordance with the JIS B 0601:2001 standard, is 4005 < Spd < 6429, and the third roll (6a) satisfies the condition that Spd is 2585 ≤ Spd < 2981. Apparatus for manufacturing electrode mixture sheets (S). [Item 4] A second roll (4) and a third roll (6) that transport an electrode mixture sheet (S) in which a dry electrode mixture (P) is compressed into a sheet, adjacent to each other at a predetermined interval, wherein the second roll (4) and the third roll (6) support the electrode mixture sheet (S) which is transported in the gap between the second roll (4) and the third roll (6), and transfer the electrode mixture sheet (S) from the second roll (4a) to the third roll (6a) of the third roll (6) and support and transport it on the third roll (6a), wherein the third roll (6a) satisfies the condition that the root mean square gradient Sdq measured in accordance with the JIS B 0601:2001 standard is 0.10 ≤ Sdq < 0.14. Apparatus for manufacturing electrode mixture sheets (S).

[0029] The following describes embodiments of the present invention, but these embodiments are merely illustrative examples for suitably illustrating the present invention and do not limit the present invention in any way.

[0030] (Example 1) A manufacturing apparatus 1 shown in Figure 1 was prepared. The second circumferential surface 4a had an Sdq of 0.096, a Spc of 50.1, a Spd of 4705, and a Str of 0.85. The third circumferential surface 6a had an Sdq of 0.13, a Spc of 66.4, a Spd of 2683, and a Str of 0.85. The Sdq, Spc, Spd, and Str of each circumferential surface were measured using a contact-type roughness tester (SURFTEST SJ-210: manufactured by Mitutoyo Corporation). The first circumferential surface 2a of the first roll 2 had a predetermined surface roughness.

[0031] The following evaluation test was performed using the manufacturing apparatus 1 according to Example 1. Specifically, an electrode mixture sheet S was formed from the dry electrode mixture P and transported, and the transferability of the electrode mixture sheet S was evaluated to see whether it could be transferred from the second circumferential surface 4a to the third circumferential surface 6a. In the evaluation of transferability, a ○ was given if the electrode mixture sheet S was transferred from the second circumferential surface 4a to the third circumferential surface 6a, and a × was given if it was not transferred. The results are shown in Figure 2.

[0032] (Example 2) An evaluation test was conducted in the same manner as in Example 1, except that the Spc of the second circumferential surface 4a was set to 53.2, Spd to 5405, and Str to 0.84, and the Sdq of the third circumferential surface 6a was set to 0.10, Spc to 48.8, and Spd to 2585. The results are shown in Figure 2.

[0033] (Example 3) An evaluation test was conducted in the same manner as in Example 1, except that the Spc of the second circumferential surface 4a was set to 54.0, Spd to 5917, and Str to 0.86, and the Sdq of the third circumferential surface 6a was set to 0.12, Spc to 61.3, Spd to 2795, and Str to 0.86. The results are shown in Figure 2.

[0034] (Comparative Example 1) An evaluation test was conducted in the same manner as in Example 1, except that the Sdq of the second circumferential surface 4a was set to 0.097, Spc to 46.2, Spd to 4005, and Str to 0.90, and the Sdq of the third circumferential surface 6a was set to 0.15, Spc to 74.0, Spd to 2981, and Str to 0.90. The results are shown in Figure 2.

[0035] (Comparative Example 2) An evaluation test was conducted in the same manner as in Example 1, except that the Sdq of the second circumferential surface 4a was set to 0.095, Spc to 54.1, Spd to 6429, and Str to 0.87, and the Sdq of the third circumferential surface 6a was set to 0.14, Spc to 75.9, Spd to 4002, and Str to 0.87. The results are shown in Figure 2.

[0036] Figure 2 shows the results of the transferability evaluation test. As shown in Figure 2, in Examples 1 to 3, where the Spc of the second circumferential surface 4a was 46.2 < Spc < 54.1 and the Spc of the third circumferential surface 6a was 48.8 ≤ Spc < 74.0, the transferability was good (○). On the other hand, in Comparative Example 1, where the Spc of the second circumferential surface 4a was 46.2 and the Spc of the third circumferential surface 6a was 74.0, and in Comparative Example 2, where the Spc of the second circumferential surface 4a was 54.1 and the Spc of the third circumferential surface 6a was 74.0 or higher, the transferability was poor (×). In Comparative Examples 1 and 2, the electrode mixture sheet S remained attached to the second circumferential surface 4a even after passing through the gap between the second roll 4 and the third roll 6. Based on the above, it was confirmed that by setting the Spc of the second circumferential surface 4a to 46.2 < Spc < 54.1 and the Spc of the third circumferential surface 6a to 48.8 ≤ Spc < 74.0, the electrode mixture sheet S can be stably transferred from the second circumferential surface 4a to the third circumferential surface 6a, thereby improving the transportability of the electrode mixture sheet S.

[0037] Furthermore, in Examples 1 to 3, where the Str of the second surface 4a was 0.84 ≤ Str < 0.87 and the Str of the third surface 6a was 0.85 ≤ Str < 0.87, the transferability was good (○). On the other hand, in Comparative Example 1, where the Str of the second surface 4a was 0.87 or higher and the Str of the third surface 6a was 0.87 or higher, and in Comparative Example 2, where the Str of the second surface 4a was 0.87 and the Str of the third surface 6a was 0.87, the transferability was poor (×). From the above, it was confirmed that the transportability of the electrode mixture sheet S can be improved by setting the Str of the second surface 4a to 0.84 ≤ Str < 0.87 and the Str of the third surface 6a to 0.85 ≤ Str < 0.87.

[0038] Furthermore, in Examples 1 to 3, where the Spd of the second circumferential surface 4a was 4005 < Spd < 6429 and the Spd of the third circumferential surface 6a was 2585 ≤ Spd < 2981, the transferability was good (○). On the other hand, in Comparative Example 1, where the Spd of the second circumferential surface 4a was 4005 and the Spd of the third circumferential surface 6a was 2981, and in Comparative Example 2, where the Spd of the second circumferential surface 4a was 6429 and the Spd of the third circumferential surface 6a was 2981 or greater, the transferability was poor (×). From the above, it was confirmed that the transportability of the electrode mixture sheet S can be improved by setting the Spd of the second circumferential surface 4a to 4005 < Spd < 6429 and the Spd of the third circumferential surface 6a to 2585 ≤ Spd < 2981.

[0039] Furthermore, in Examples 1 to 3, where the Sdq of the third circumferential surface 6a was 0.10 ≤ Sdq < 0.14, the transferability was good (○). On the other hand, in Comparative Example 1, where the Sdq of the third circumferential surface 6a was 0.14 or greater, and in Comparative Example 2, where the Sdq of the third circumferential surface 6a was 0.14, the transferability was poor (×). From the above, it was confirmed that the transportability of the electrode mixture sheet S can be improved by setting the Sdq of the third circumferential surface 6a to 0.10 ≤ Sdq < 0.14.

[0040] This disclosure can be used in a manufacturing apparatus for electrode mixture sheets.

[0041] 1 Manufacturing apparatus, 4 Second roll, 4a Second surface, 6 Third roll, 6a Third surface, P Dry electrode mixture, S Electrode mixture sheet.

Claims

1. An apparatus for manufacturing electrode mixture sheets, comprising a second roll and a third roll that transport an electrode mixture sheet, in which a dry electrode mixture is compressed into a sheet, adjacent to each other at a predetermined interval, wherein the second roll and the third roll each transfer the electrode mixture sheet, which is supported by the second circumferential surface of the second roll and transported in the gap between the second roll and the third roll, from the second circumferential surface to the third circumferential surface of the third roll, where it is supported and transported by the third circumferential surface, wherein the arithmetic mean curvature Spc of the peak, measured in accordance with the JIS B 0601:2001 standard, satisfies the condition that 46.2 < Spc < 54.1, and the third circumferential surface satisfies the condition that Spc is 48.8 ≤ Spc < 74.

0.

2. An apparatus for manufacturing electrode mixture sheets, comprising a second roll and a third roll that transport an electrode mixture sheet, in which a dry electrode mixture is compressed into a sheet, adjacent to each other at a predetermined interval, wherein the second roll and the third roll transfer the electrode mixture sheet, which is supported by the second circumferential surface of the second roll and transported in the gap between the second roll and the third roll, from the second circumferential surface to the third circumferential surface of the third roll, and support and transport the sheet on the third circumferential surface, wherein the aspect ratio Str of the surface properties measured in accordance with the JIS B 0601:2001 standard satisfies the condition of 0.84 ≤ Str < 0.87, and the third circumferential surface satisfies the condition of Str being 0.85 ≤ Str < 0.

87.

3. An apparatus for manufacturing electrode mixture sheets, comprising a second roll and a third roll that transport an electrode mixture sheet, in which dry electrode mixture is compressed into a sheet, adjacent to each other at a predetermined interval, wherein the second roll and the third roll transfer the electrode mixture sheet, which is supported by the second circumferential surface of the second roll and transported in the gap between the second roll and the third roll, from the second circumferential surface to the third circumferential surface of the third roll, and support and transport it on the third circumferential surface, wherein the second circumferential surface satisfies the condition that the peak density Spd of the mountain, measured in accordance with the JIS B 0601:2001 standard, is 4005 < Spd < 6429, and the third circumferential surface satisfies the condition that Spd is 2585 ≤ Spd < 2981.

4. An electrode mixture sheet manufacturing apparatus comprising a second roll and a third roll that transport an electrode mixture sheet, in which a dry electrode mixture is compressed into a sheet, adjacent to each other at a predetermined interval, wherein the second roll and the third roll transfer the electrode mixture sheet, which is supported by the second circumferential surface of the second roll and transported in the gap between the second roll and the third roll, from the second circumferential surface to the third circumferential surface of the third roll, and support and transport the sheet with the third circumferential surface, wherein the third circumferential surface satisfies the condition that the root mean square gradient Sdq measured in accordance with the JIS B 0601:2001 standard is 0.10 ≤ Sdq < 0.14.

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