Electrode manufacturing method and electrode rolling device

Abstract

To provide a manufacturing method of an electrode that prevents damage to an active material layer non-formed part when pressing an electrode sheet with a pressure roll.SOLUTION: A manufacturing method of an electrode includes: a step of preparing an electrode sheet 100 in which an active material layer 103 containing an electrode active material is formed, except for a non-formed part 102 set on at least one end in the width direction orthogonal to the longitudinal direction of strip-shaped current collector foil; and a rolling step of rolling the active material layer 103 by making the electrode sheet 100 pass between a pair of pressure rolls 11, 12. In the rolling step, oil 30 is supplied to at least a portion opposed to the non-formed part 102 of the pair of pressure rolls 11, 12.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an electrode and an electrode rolling apparatus. [Background technology]

[0002] JP 2014-29806 A discloses an electrode manufacturing apparatus. The apparatus manufactures a strip-shaped electrode sheet. The manufactured strip-shaped electrode sheet has an uncoated region of a predetermined width extending longitudinally on at least one end of the width direction of the electrode roll, where no active material is applied, and a coated region in which active material is continuously applied longitudinally to the remaining width direction to form an active material layer. In the apparatus, an insulating material that will become the insulating layer is applied longitudinally to a predetermined insulating region along the boundary between the uncoated region and the coated region at least either before or after the active material is applied to the electrode roll. The electrode manufacturing apparatus discloses that, after the active material layer is formed, the active material layer is roll-pressed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-29806 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when the electrode sheet is pressed by the rolling rolls, damage may occur in the unformed portions. [Means for solving the problem]

[0005] The electrode manufacturing method disclosed herein includes the steps of: preparing an electrode sheet on which an active material layer containing an electrode active material is formed, excluding an unformed portion set at at least one end of a strip-shaped current collector foil in a width direction perpendicular to the longitudinal direction; and rolling the electrode sheet between a pair of rolling rolls to roll out the active material layer. In the rolling step, oil is supplied to at least a portion of the pair of rolling rolls facing the unformed portion. By supplying oil to at least a portion of the pair of rolling rolls facing the unformed portion, damage to the unformed portion is suppressed.

[0006] The electrode rolling apparatus disclosed herein is an apparatus for rolling an electrode sheet including an electrode active material layer continuously applied along the longitudinal direction of a strip-shaped current collector foil and containing an electrode active material, and an unformed portion where the electrode active material layer is not disposed at least at one end of the current collector foil in a width direction perpendicular to the longitudinal direction. Here, the electrode rolling apparatus includes a conveying device that feeds the electrode sheet along a predetermined conveying path, a pair of rolling rolls arranged on the conveying path along which the electrode sheet is conveyed, and an oil supplying mechanism that supplies oil to the surfaces of the rolling rolls in areas that sandwich the unformed portion of the electrode sheet. In this case, too, supplying oil to at least the portions of the pair of rolling rolls that face the unformed portion suppresses damage to the unformed portion. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a front view schematically showing an electrode rolling device 10. As shown in FIG. [Figure 2] FIG. 2 is a side view schematically showing the rolling process carried out by the electrode rolling device 10. As shown in FIG. [Figure 3] FIG. 3 is a graph showing the tendency of the amount of wear on the surfaces of the rolls 11 and 12. In FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] The disclosure herein is explained below. Unless otherwise specified, the disclosure herein is not intended to limit the invention described in the claims of this application. Each drawing is a schematic drawing and does 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 will be 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.

[0009] Fig. 1 is a front view that schematically shows an electrode rolling apparatus 10. Fig. 2 is a side view that schematically shows a rolling process performed by the electrode rolling apparatus 10. Fig. 2 is a schematic view of the pair of rolls 11, 12 as viewed from the side (left side of Fig. 1) from which an electrode sheet 100 rolled by the rolls 11, 12 exits. The electrode rolling apparatus 10 embodies the electrode manufacturing method disclosed herein.

[0010] The electrode manufacturing method disclosed herein includes a step of preparing an electrode sheet 100 and a rolling step of rolling an active material layer. In the electrode manufacturing method, the electrode sheet 100 is rolled as shown in FIG.

[0011] <Electrode sheet 100> The electrode sheet 100 is prepared in a process for preparing an electrode sheet 100. The electrode sheet 100 has an active material layer 103 containing an electrode active material formed thereon, except for an unformed portion 102 set at at least one end of the width direction perpendicular to the longitudinal direction of the strip-shaped current collector foil. Such an electrode sheet 100 can be used as an electrode sheet for an electricity storage device, such as a positive electrode sheet or negative electrode sheet for a lithium-ion secondary battery.

[0012] Here, "electrode sheet" refers to an electrode sheet used in an electricity storage device, regardless of whether it is a positive electrode sheet or a negative electrode sheet. "Electricity storage device" refers to a device that can be charged and discharged. Electricity storage devices include batteries generally referred to as lithium ion batteries and lithium secondary batteries, as well as lithium polymer batteries and lithium ion capacitors. A secondary battery generally refers to a battery that can be repeatedly charged and discharged through the movement of charge carriers between the positive and negative electrodes. An electricity storage device may use an electrolyte solution or a solid electrolyte. For example, the secondary battery may be a secondary battery that uses a so-called liquid electrolyte solution, or a so-called all-solid-state battery that uses a solid electrolyte.

[0013] Here, the positive electrode sheet is a positive electrode current collector foil (e.g., aluminum foil) of a predetermined width and thickness, on both sides of which a positive electrode active material layer containing a positive electrode active material is formed, except for an unformed portion set at one end of the width direction with a certain width. In a lithium ion secondary battery, the positive electrode active material is, for example, a material that can release lithium ions during charging and absorb lithium ions during discharging, such as a lithium transition metal composite material. Generally, various positive electrode active materials have been proposed in addition to lithium transition metal composite materials, and there is no particular limitation.

[0014] Here, the negative electrode sheet is a negative electrode current collector foil (copper foil in this case) of a predetermined width and thickness, on both sides of which a negative electrode active material layer containing a negative electrode active material is formed, except for an unformed portion set at a certain width on one edge in the width direction. In a lithium ion secondary battery, for example, the negative electrode active material is a material, such as natural graphite, that can absorb lithium ions during charging and release the absorbed lithium ions during discharging. Generally, various negative electrode active materials other than natural graphite have been proposed, and there is no particular limitation.

[0015] In the embodiment shown in FIG. 2, the electrode sheet 100 has an active material layer 103 provided in the widthwise middle portion of a substrate made of a strip-shaped metal foil. The active material layer 103 is a layer containing active material particles, and is applied to a predetermined width in the widthwise middle portion of the substrate at a predetermined thickness (basis weight) and is left to dry. After a compression process, the electrode sheet 100 is cut at the widthwise middle portion to obtain two electrode sheets. In the two obtained electrode sheets, the active material layer is formed in the portions excluding an unformed portion 102 set at one end in the widthwise direction. The configuration of the electrode sheet 100 is not limited to the embodiment shown in FIG. 2.

[0016] For example, in this embodiment, protective layers 104 containing inorganic filler are provided on both widthwise ends of the active material layer 103. The protective layers 104 are preferably provided on both widthwise ends of the active material layer 103 in a coating process. The protective layers 104 are preferably formed by coating a paste material containing electrically insulating particles such as alumina. The protective layers 104 are layers that protect the active material layer 103.

[0017] The protective layer 104 is provided, for example, when the electrode sheet 100 is a positive electrode sheet. The protective layer 104 is disposed so as to face the edge of the negative electrode sheet. The edge of the negative electrode sheet is cut during the manufacturing process of the negative electrode sheet, and therefore, burrs may be generated or foreign metal matter may be attached. The protective layer 104 prevents the edge of the negative electrode sheet or foreign metal matter from coming into contact with the positive electrode current collector. For this reason, it is desirable that the protective layer 104 is not easily broken through even when burrs are generated on the edge of the negative electrode sheet or when foreign metal matter is present.

[0018] An inorganic filler can be used for the electrically insulating particles contained in the protective layer 104. In addition to alumina, examples of inorganic fillers that can be used include boehmite, silica, mica, and hydrous magnesium silicate. Boehmite is cheaper than alumina, so the manufacturing cost of the secondary battery can be kept low. Inexpensive inorganic fillers that can be used include boehmite, silica, hydrous magnesium silicate, and the like.

[0019] 1, in the rolling step, the electrode sheet 100 is passed between a pair of rolling rolls 11 and 12 to roll out the active material layer 103. By rolling out the active material layer 103, the electrode sheet 100 including the active material layer 103 is adjusted to an appropriate thickness.

[0020] Incidentally, the present inventor has found that when the electrode sheet 100 is sandwiched and rolled between the rolling rolls 11 and 12, an event occurs in which the unformed portion 102 breaks. The present inventor believes that this is because when a foreign object is attached to either the rolling rolls 11 and 12 or the unformed portion 102, the unformed portion 102 gets caught on the rolling rolls 11 and 12 and is damaged.

[0021] FIG. 3 is a graph showing the trend in the amount of wear on the surfaces of the rolling rolls 11 and 12. FIG. 3 shows the relationship between the widthwise position of the rolling rolls 11 and 12 and the amount of wear on the surfaces of the rolling rolls 11 and 12. The surfaces of the rolling rolls 11 and 12 wear over time with use. FIG. 3 shows the amount of wear at the end of one side of the widthwise direction of the electrode sheet 100, at the locations where, from left to right, the unformed portion 102, protective layer 104, and active material layer 103 come into contact. Here, area A in FIG. 3 is approximately the portion where the unformed portion 102 of the electrode sheet 100 comes into contact. Area B in FIG. 3 is approximately the portion where the protective layer 104 formed on the edge of the active material layer 103 of the electrode sheet 100 comes into contact. Area C in FIG. 3 is approximately the portion where the active material layer 103 of the electrode sheet 100 comes into contact.

[0022] As shown in FIG. 3, the surfaces of the rolling rolls 11 and 12 are worn away with use. In this case, the portion C that contacts the active material layer 103 is most susceptible to wear, followed by the portion B that contacts the protective layer 104. The portion A that contacts the unformed portion 102 tends to be less susceptible to wear. As a result, with use, the rolling rolls 11 and 12 experience a difference in the amount of wear between the portion C that contacts the active material layer 103 and the portion A that contacts the unformed portion 102. For this reason, a step is formed on the surfaces of the rolling rolls 11 and 12 between the portion A that contacts the unformed portion 102 and the portion C that contacts the active material layer 103.

[0023] In the example shown in FIG. 3, a protective layer 104 is provided on the edge of the active material layer 103 of the electrode sheet 100. In this case, as shown in FIG. 3, almost no wear is observed at the end of portion A of the rolling rolls 11 and 12 where the unformed portion 102 comes into contact. In contrast, wear becomes more apparent as one approaches the edge of the protective layer 104. Furthermore, in the portion facing the protective layer 104, wear is greater in the vicinity S1 of the edge of the protective layer 104, and the wear also becomes greater as one approaches the edge of the active material layer 103. In portion C where the active material layer 103 comes into contact, wear is observed to be significantly greater than in portion A where the unformed portion 102 comes into contact and portion B where the protective layer 104 comes into contact.

[0024] In the example shown in FIG. 3 , a step S3 of about 35 μm has been created due to the difference in the amount of wear between portion C where active material layer 103 contacts and portion A where unformed portion 102 contacts. If such a step S3 has been created in the rolling rolls 11 and 12, it can cause unformed portion 102 of electrode sheet 100 to get caught. Unformed portion 102 is formed from a thin metal foil. Therefore, if the end of unformed portion 102 gets caught on the rolling rolls 11 and 12, it can cause damage to unformed portion 102, such as breaking of unformed portion 102 starting from the caught location.

[0025] In the electrode manufacturing method proposed here, as shown in FIG. 2, oil 30 is supplied to at least the portion of the pair of rolling rolls 11, 12 that faces the unformed portion 102 in the rolling step.

[0026] By supplying oil 30 to at least the portion of the pair of rolling rolls 11, 12 facing the unformed portion 102, the unformed portion 102 becomes more easily slippery even when it comes into contact with the pair of rolling rolls 11, 12. Therefore, even if foreign matter is attached to either the rolling rolls 11, 12 or the unformed portion 102, or if steps are formed on the surfaces of the rolling rolls 11, 12 due to wear, the unformed portion 102 of the electrode sheet 100 is less likely to get caught on the rolling rolls 11, 12, and the unformed portion 102 is less likely to be damaged.

[0027] For example, as shown in FIG. 3 , the oil 30 may be supplied to portion A where the unformed portion 102 comes into contact. Furthermore, if the electrode sheet 100 has a protective layer 104, the oil 30 may be supplied so that it covers portion B where the protective layer 104 comes into contact. It is preferable that the oil 30 does not remain on the active material layer 103. For this reason, it is preferable that the oil 30 is not supplied so that it covers portion C where the active material layer 103 comes into contact. Note that if the oil 30 is volatile and does not remain over time, there is no problem even if it adheres to the active material layer 103. In this case, some of the oil 30 may cover the active material layer 103.

[0028] For example, when the width of the unformed portion 102 of the electrode sheet 100 is taken as 100%, the oil 30 is preferably supplied to a region of the rolling rolls 11 and 12 that faces the unformed portion 102 of the electrode sheet 100 over a width of 80 to 120% of the width. Also, for example, as shown in Fig. 3, when the electrode sheet 100 has a protective layer 104, when the combined width T1 of the unformed portion 102 and the protective layer 104 is taken as 100%, the width T2 over which the oil 30 is applied is set to a width of 80 to 120%, and the oil 30 is preferably supplied to a region of the rolling rolls 11 and 12 that faces the unformed portion 102 and the protective layer 104 of the electrode sheet 100. For example, if the width T1 of the unformed portion 102 (including the protective layer 104) of the electrode sheet 100 is 35 mm, as shown in Figure 2, oil 30 may be supplied to both ends of the width direction of the portion through which the electrode sheet 100 is passed, with a width of 30 mm or more and 40 mm or less.

[0029] Although it is not necessarily necessary to supply oil 30 to all areas facing the unformed portions 102 of the electrode sheet 100, the inventors have found that it is preferable to supply oil 30 to the portion facing the end of the electrode sheet 100 on the side where the unformed portions 102 have been formed. By supplying oil 30 to the portion facing the end of the electrode sheet 100 on the side where the unformed portions 102 have been formed, the end of the unformed portions 102 of the electrode sheet 100 is less likely to get caught on the rolling rolls 11, 12, and damage to the unformed portions 102 of the electrode sheet 100 caused by the end of the unformed portions 102 of the electrode sheet 100 getting caught on the rolling rolls 11, 12 can be prevented.

[0030] According to the findings of the present inventors, for example, it is preferable that oil 30 be supplied to both widthwise ends of the pair of rolling rolls, particularly to the portion corresponding to the electrode sheet 100. In the rolling process, it is preferable that oil 30 be applied to both widthwise ends of the pair of rolling rolls, at the portion through which the electrode sheet 100 passes, with a width of 30 mm to 40 mm. In this case, oil 30 is applied to the rolling rolls 11, 12 with a sufficient width for the end of the unformed portion 102 of the electrode sheet 100. Therefore, even if the end of the unformed portion 102 of the electrode sheet 100 comes into contact with the rolling rolls 11, 12, it is unlikely to get caught on the rolling rolls 11, 12, and the unformed portion 102 is unlikely to be damaged.

[0031] In the rolling process, oil may be supplied to the circumferential side surfaces of the rolls 11 and 12 on the downstream side in the conveyance direction of the electrode sheet 100. In this case, after the oil 30 is supplied to the surfaces of the rolls 11 and 12, the oil 30 becomes familiar with the surfaces of the rolls 11 and 12 by the time it reaches the part of the electrode sheet 100 that is to be rolled, and unevenness of the oil 30 is kept small.

[0032] As shown in FIG. 2, the electrode sheet 100 may be provided with a protective layer 104 containing an inorganic filler on the edge of the active material layer 103. In this case, it is preferable that the oil 30 is supplied to at least a part of the region of the rolling rolls 11 and 12 that faces the protective layer 104. This makes it easier for the protective layer 104 and the unformed portion 102 to slide on the surfaces of the rolling rolls 11 and 12 and is less likely to get caught on the rolling rolls 11 and 12. Therefore, even if steps due to the protective layer 104 occur on the surfaces of the rolling rolls 11 and 12 or if foreign matter adheres to those areas, the unformed portion 102 is less likely to be damaged.

[0033] The oil 30 to be supplied here should volatilize and disappear over time and not remain on the electrode sheet 100. For example, an isoparaffin-based hydrocarbon solvent or the like can be used. Examples of the oil 30 that can be used include commercially available oils such as Aqua Chemical Co., Ltd.'s no-clean processing oils GS-5A and GS-7A. The oil 30 to be supplied should be able to keep the friction between the pair of rolls 11, 12 and the electrode sheet 100 low and should volatilize and disappear over time. From this perspective, the oil 30 is not limited to the above. In addition to the above-mentioned isoparaffin-based hydrocarbon solvent, various oils having similar functions can be used as the oil 30 to be supplied to the surfaces of the rolls 11, 12.

[0034] Various methods can be considered for supplying the oil 30. The present inventors have considered applying the oil 30 to predetermined areas on the surfaces of the rolls 11 and 12. In this case, it is easy to control the width and amount of oil 30 to be supplied, and it is easy to supply an appropriate amount of oil 30 to an appropriate area.

[0035] The electrode rolling apparatus 10 shown in FIG. 1 embodies such an electrode manufacturing method. As shown in FIG. 1, the electrode rolling device 10 includes a conveying device 40, a pair of rolling rolls 11 and 12, and an oil supply mechanism 14.

[0036] The conveying device 40 may be a device that feeds the strip-shaped electrode sheet 100 along a predetermined conveying path 40a. As schematically shown in FIG. 1 , the conveying device 40 may be a device that conveys the strip-shaped electrode sheet 100 roll-to-roll along the predetermined conveying path 40a. In this case, the strip-shaped electrode sheet 100 before being rolled may be prepared by being wound up on a roll 41 in advance. The conveying device 40 may send out the electrode sheet 100 from the roll 41 along the conveying path 40a, pass it through a pair of rolling rolls 11 and 12, and then wind the rolled electrode sheet 100 on a roll 42.

[0037] <A pair of rolling rolls 11, 12> The pair of rolling rolls 11, 12 are arranged on the transport path 40a along which the electrode sheet 100 is transported. The pair of rolling rolls 11, 12 may each be a cylindrical roll. As described above, the surfaces of the rolling rolls 11, 12 wear with use, so they are preferably replaceable components. The pair of rolling rolls 11, 12 are preferably configured to rotate along the transport direction of the transport path 40a along which the electrode sheet 100 is transported. Although not shown, the pair of rolling rolls 11, 12 are incorporated into a press machine, and the distance between them is adjusted. The press machine applies a force P to the rotation axes 11a, 12a of the pair of rolling rolls 11, 12 in directions facing each other. As a result, the electrode sheet 100 passing through the pair of rolling rolls 11, 12 is rolled.

[0038] <Oil supply mechanism 14> The oil supply mechanism 14 is a mechanism that supplies oil to the surfaces of the rolling rolls 11, 12 in the regions of the rolling rolls 11, 12 that sandwich the unformed portion 102 of the electrode sheet 100. In this embodiment, as shown in FIG. 1 , the oil supply mechanism 14 includes a mechanism 14A that supplies oil 30 to the outer peripheral surface of the rolling roll 11, and a mechanism 14B that supplies oil 30 to the outer peripheral surface of the rolling roll 12. In this embodiment, the oil supply mechanism 14 is configured as a mechanism that applies oil 30 to the surfaces of the rolling rolls 11, 12. The oil supply mechanisms 14A, 14B each include an application member 51 and a supply member 52.

[0039] <Applicator member 51> Here, the applicator 51 is a member that is brought into contact with each of the pair of rolling rolls 11, 12. The applicator 51 is preferably a member that can be soaked with oil 30, such as felt, sponge, or nonwoven fabric. Furthermore, since the applicator 51 is pressed against the pair of rolling rolls 11, 12 with a required force, it is preferable to use a member that has good slip properties, abrasion resistance, and water retention (oil retention). In this embodiment, the applicator 51 is attached to the tip of an arm 51a.

[0040] <Supply member 52> The supply member 52 is a member that supplies oil 30 to the application member 51. The supply member 52 is attached, for example, along the arm 51a, and can be configured as a pipe that supplies the oil 30 to the application member 51. As shown in FIG. 1, the oil supply mechanism 14 preferably includes a tank 53, a pump 54, and a check valve 55, which are connected to each other by a pipe 56. The oil is then supplied from the tank 53 to the supply member 52 through the pipe 56 by the pump 54, and the oil 30 is then supplied from the supply member 52 to the application member 51. The check valve 55 is a device that prevents the oil 30 from flowing back.

[0041] 1, the oil supply mechanism 14 includes application members 51 that contact the pair of rolls 11, 12, respectively, and a supply member 52 that supplies oil to the application members 51. This allows oil 30 to be continuously supplied to the surfaces of the pair of rolls 11, 12 through the application members 51.

[0042] The oil supply mechanism 14 may include a spring mechanism 61 that biases the applicator 51 toward each of the pair of rolls. For example, the angle of the arm 51a may be variable, and the spring mechanism 61 may be configured to press the applicator 51 attached to the tip of the arm 51a toward the surfaces of the pair of rolls 11 and 12. By providing a spring mechanism that biases the applicator 51 toward each of the pair of rolls 11 and 12, the applicator 51 is pressed against the surfaces of the rolls 11 and 12 with a stable force. This allows oil to be stably supplied to the surfaces of the rolls 11 and 12. Furthermore, because the oil 30 is stably supplied to the surfaces of the rolls 11 and 12, damage to the unformed portions 102 caused by the electrode sheet 100 getting caught on the rolls 11 and 12 is prevented. The specific structure of the spring mechanism 61 may take various forms. For example, a spring (not shown) that generates an elastic reaction force so that the arm 51a tilts toward the surfaces of the pair of rolls 11 and 12 may be incorporated into the angle adjustment mechanism of the arm.

[0043] The oil supply mechanism 14 is configured so that the applicator 51 is pressed against the surface of the rolling rolls 11, 12 against the side peripheral surface downstream in the conveying direction of the electrode sheet 100 in the circumferential direction of the rolling rolls 11, 12. Here, the side peripheral surface of the rolling rolls 11, 12 downstream in the conveying direction of the electrode sheet 100 refers to the side peripheral surface of the half portion downstream in the conveying direction of the electrode sheet 100 when the rolling rolls 11, 12 are divided in half by a straight line connecting the rotation center of the rolling rolls 11, 12 and the part on the circumference where the electrode sheet 100 is sandwiched between the rolling rolls 11, 12. The application member 51 is pressed against the surfaces of the rolling rolls 11 and 12 on the side peripheral surface downstream in the conveying direction of the electrode sheet 100, so that the oil 30 becomes familiar with the surfaces of the rolling rolls 11 and 12 from the time the oil 30 is supplied to the surfaces of the rolling rolls 11 and 12 until it reaches the part of the electrode sheet 100 that is being rolled, thereby minimizing unevenness in the oil 30.

[0044] In this way, the electrode rolling device 10 is equipped with an oil supply mechanism 14 that supplies oil 30 to the surfaces of the rolling rolls 11, 12 in the areas of the rolling rolls 11, 12 that sandwich the unformed portions 102 of the electrode sheet 100. Because the oil 30 is supplied to the surfaces of the rolling rolls 11, 12 in the areas of the rolling rolls 11, 12 that sandwich the unformed portions 102 of the electrode sheet 100, even if foreign matter is attached to either the rolling rolls 11, 12 or the unformed portions 102, or if steps are generated on the surfaces of the rolling rolls 11, 12 due to wear, the unformed portions 102 of the electrode sheet 100 are less likely to get caught on the rolling rolls 11, 12 and the unformed portions 102 are less likely to be damaged.

[0045] Although the electrode rolling apparatus 10 has been described above, the electrode rolling apparatus 10 is not limited to the above. For example, the oil supply mechanism 14 has been described as being configured so that the applicator member 51 is pressed against the surfaces of the rolls 11 and 12. The oil supply mechanism 14 is not limited to this configuration. Although not shown in the drawings, a method for supplying oil to the surfaces of the rolls 11 and 12 may be, for example, to drip a predetermined amount of oil onto predetermined positions on the surfaces of the rolls 11 and 12. Alternatively, the oil may be sprayed onto predetermined positions on the surfaces of the rolls 11 and 12. Alternatively, after dripping or spraying the oil, the oil may be spread to a predetermined width by pressing a wiper against the surfaces of the rolls 11 and 12 to which the oil has been supplied.

[0046] 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.

[0047] As described above, this specification includes the disclosures set forth in the following sections.

[0048] Section 1: preparing an electrode sheet on which an active material layer containing an electrode active material is formed, excluding an unformed portion set at at least one end portion in a width direction perpendicular to the longitudinal direction of a strip-shaped current collector foil; a rolling step of rolling the active material layer by passing the electrode sheet between a pair of rolling rolls; Including, In the rolling step, oil is supplied to at least a portion of the pair of rolling rolls facing the unformed portion. Electrode manufacturing method.

[0049] Section 2: Item 2. The manufacturing method according to Item 1, wherein in the rolling step, oil is supplied to a region of the rolling roll facing the unformed portion of the electrode sheet in a width of 80 to 120% when the width of the unformed portion of the electrode sheet is taken as 100%.

[0050] Section 3: Item 3. The manufacturing method according to item 1 or 2, wherein in the rolling step, the oil is supplied to both ends of the pair of rolling rolls in the width direction of a portion through which the electrode sheet passes, with a width of 30 mm or more and 40 mm or less.

[0051] Section 4: 4. The manufacturing method according to any one of items 1 to 3, wherein in the rolling step, the oil is supplied to a side peripheral surface of the rolling roll on a downstream side in a conveying direction of the electrode sheet in the circumferential direction.

[0052] Section 5: 5. The manufacturing method according to claim 1, wherein the electrode sheet has a protective layer containing an inorganic filler provided on an edge of the active material layer, and the oil is supplied to at least a part of an area facing the protective layer.

[0053] Item 6: Item 6. The manufacturing method according to Item 5, wherein in the rolling step, oil is supplied to a region of the rolling roll that faces the unformed portion of the electrode sheet and the protective layer in a width of 80 to 120% when the combined width of the unformed portion of the electrode sheet and the protective layer is taken as 100%.

[0054] Section 7: Item 1. The manufacturing method according to item 1, wherein the oil is applied to the surface of the rolling roll.

[0055] Section 8: An electrode rolling device for rolling an electrode sheet comprising: an electrode active material layer continuously applied along the longitudinal direction of a strip-shaped current collector foil and containing an electrode active material; and an unformed portion in which the electrode active material layer is not disposed at at least one end portion in a width direction perpendicular to the longitudinal direction of the current collector foil, the electrode sheet comprising: a conveying device that conveys the electrode sheet along a predetermined conveying path; a pair of rolling rolls disposed in a transport path along which the electrode sheet is transported; an oil supply mechanism that supplies oil to the surface of the rolling roll in a region of the rolling roll that sandwiches the unformed portion of the electrode sheet; Equipped with Electrode rolling equipment.

[0056] Section 9: The oil supply mechanism includes an application member that contacts each of the pair of rolls; a supply member that supplies oil to the application member; Item 9. The electrode rolling device according to item 8, comprising:

[0057] Section 10: Item 10. The electrode rolling device according to item 9, wherein the oil supply mechanism includes a spring mechanism that urges the application member toward each of the pair of rolling rolls.

[0058] Section 11: Item 10. The electrode rolling device according to item 9, wherein the oil supply mechanism is configured so that the application member is pressed against the surface of the rolling roll on a side peripheral surface downstream in a conveying direction of the electrode sheet in the circumferential direction of the rolling roll. [Explanation of symbols]

[0059] 10 Electrode rolling equipment 11,12 Rolling mill 11a, 12a Rotation axis 14 Oil supply mechanism 14A Mechanism for supplying oil 30 to the outer peripheral surface of the rolling roll 11 14B Mechanism for supplying oil 30 to the outer peripheral surface of the rolling roll 12 30 oil 40 Conveyor 40a Transport route 41 rolls 42 rolls 51 Coating material 51a Arm 52 Supply materials 53 Tank 54 Pump 55 Check valve 56 Piping 61 Spring mechanism 100 electrode sheets 102 Unformed part 103 Active material layer 104 Protective layer A: The part where the unformed part 102 comes into contact B: The portion where the protective layer 104 comes into contact C: The portion in contact with the active material layer 103 S1: Near the edge of the protective layer 104 S3 Step T1: Combined width of the unformed portion 102 and the protective layer 104 T2 Width where oil 30 is applied

Claims

1. preparing an electrode sheet in which an active material layer containing an electrode active material is formed continuously in the longitudinal direction on both sides of a strip-shaped current collecting foil, excluding an unformed portion set at at least one end in a width direction perpendicular to the longitudinal direction; a rolling step of rolling the active material layer by passing the electrode sheet between a pair of rolling rolls in one direction; Including, In the rolling step, a volatile oil is continuously applied to a region of the surface of the pair of rolling rolls, on a side peripheral surface on a downstream side in a conveying direction of the electrode sheet, the region facing the unformed portion of the electrode sheet, including an end portion of the unformed portion of the electrode sheet; Electrode manufacturing method.

2. A method for manufacturing an electrode as described in claim 1, wherein in the rolling process, an application member impregnated with the volatile oil is continuously pressed against the side peripheral surface of the pair of rolling rolls downstream in the conveying direction of the electrode sheet, in an area facing the unformed portion of the electrode sheet, including the end of the unformed portion of the electrode sheet.

3. The electrode sheet has a protective layer containing an inorganic filler provided on the edges of the active material layers on both sides, the volatile oil is continuously applied to a region of the surface of the pair of rolling rolls facing the unformed portion of the electrode sheet, including an end of the unformed portion of the electrode sheet, and the protective layer; A method for producing the electrode according to claim 1 or 2.

4. An electrode rolling device that rolls an electrode sheet in which an active material layer containing an electrode active material is formed continuously in the longitudinal direction on both sides, except for an unformed portion set at at least one end of a width direction perpendicular to the longitudinal direction of a strip-shaped current collecting foil, a conveying device that feeds the electrode sheet in one direction along a predetermined conveying path during rolling; A pair of rolling rolls arranged on the transport path; an oil supply mechanism that supplies oil to a region of the rolling roll that sandwiches the unformed portion of the electrode sheet; Equipped with The oil supply mechanism includes: application members that are in contact with regions of the surfaces of the pair of rolling rolls, on side peripheral surfaces downstream in a conveying direction of the electrode sheet with respect to the pair of rolling rolls, that face the unformed portion of the electrode sheet, including end portions of the unformed portion of the electrode sheet; a supplying member that supplies volatile oil to the application member and allows the application member to soak in the oil; a spring mechanism that biases the application member toward each of the pair of rolling rolls; Equipped with Electrode rolling equipment.

5. The oil supply mechanism an arm having the application member attached to a tip thereof; an angle adjustment mechanism that tilts the arm toward the surfaces of the pair of rolling rolls, thereby pressing the application member against the surfaces of the pair of rolling rolls; Furthermore, 5. The electrode rolling device according to claim 4, wherein a spring is incorporated in the angle adjustment mechanism.

6. The electrode sheet has a protective layer containing an inorganic filler provided on the edges of the active material layers on both sides, 6. The electrode rolling device according to claim 4, wherein the coating member is arranged to contact an unformed portion of the electrode sheet, including an end of the unformed portion of the electrode sheet, and an area facing the protective layer during rolling.

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