Rolling roll, method for manufacturing rolling roll, and method for manufacturing electrode using same

Abstract

A rolling roll according to an embodiment of the present invention comprises: a roll base material; and a chromium-containing plating layer which is formed on the roll base material and in which the maximum length of cracks formed on the surface thereof is 5 µm or less. A rolling roll according to another embodiment of the present invention comprises: a roll base material; a chromium-containing plating layer formed on the roll base material; and a first coating layer formed on the chromium-containing plating layer and containing a titanium nitride. A method for manufacturing a rolling roll according to another embodiment of the present invention comprises the steps of: forming surface recesses and projections on the surface of a roll base material; forming a chromium-containing plating layer on the roll base material by using a plating solution containing a chromium-containing raw material and sulfuric acid; and applying a metal nitride onto the chromium-containing plating layer. In the step of forming the chromium-containing plating layer, the plating solution further contains a sulfonic acid-based organic catalyst, or plating is performed in a state in which the plating solution has been heated to 65-90°C. A method for manufacturing a secondary battery according to another embodiment of the present invention comprises the steps of: forming an electrode active material layer on a current collector; and rolling the electrode active material layer using said rolling roll.

Description

Rolling roll, method for manufacturing a rolling roll, and method for manufacturing an electrode using the same

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0145925 filed October 23, 2024 and Korean Patent Application No. 10-2025-0038136 filed March 25, 2025, and all contents disclosed in the documents of said Korean patent applications are incorporated herein as part of this specification.

[0003] The present invention relates to a rolling roll, a method for manufacturing a rolling roll, and a method for manufacturing an electrode through the same, comprising: a roll base material; and a chromium-containing plating layer formed on the roll base material, wherein the maximum length of a crack formed on the surface is 5 μm or less.

[0004] The manufacturing process of secondary battery electrodes proceeds through mixing, coating, rolling, slitting and notching, and drying processes. In particular, during the rolling process, the coated active material electrode is rolled to reduce its thickness and improve density. However, during the rolling process, as the active material electrode passes between a pair of upper and lower rolling rolls and the upper and lower rolling rolls are compressed to reduce the thickness of the active material electrode, friction may occur between the surface of the rolling roll and the active material electrode. Consequently, there is a problem in that the surface of the rolling roll wears down during the rolling process, thereby shortening the lifespan of the rolling roll.

[0005] To prevent these problems, a hard chrome plating layer is generally formed on the surface of rolling rolls to increase their hardness to approximately 700–900 Hv, thereby reducing wear and extending their service life. However, hard chrome plating uses a plating bath containing a mixture of anhydrous chromic acid and sulfuric acid (CrO3 and H2SO4). Residual hydrogen generated in the bath can cause hydrogen embrittlement through hydrogen penetration into the base material, and residual stress during plating can lead to hair cracks in the plating layer. These hair cracks are large enough to allow the plating solution to penetrate, causing the solution to leak out and remain on the roll surface during heat treatment for hydrogen removal, which can lead to defects during subsequent high-hardness coating. Furthermore, the possibility cannot be ruled out that polishing and cleaning solutions may penetrate the cracks during the roll surface polishing and cleaning processes—preparatory steps prior to high-hardness coating—causing surface defects. Furthermore, if hairline cracks on the plating surface propagate due to stress caused by rolling loads, the cracks may connect and detach, becoming a critical cause of shortened roll life.

[0006] In order to further increase the service life of the rolls, there are cases where rolling is performed by adding DLC ​​(Diamond Like Carbon) deposition or WC (tungsten carbide) coating on the hard chrome plating layer to increase the hardness of the rolling rolls to the level of 2,000 Hv.

[0007] DLC is deposited using a hydrocarbon (CnHn) plasma gas, which can increase hardness to the level of 2,000 Hv, but the coefficient of friction is excessively low at the level of 0.05, which can cause slip during rolling. Furthermore, since a large amount of hydrogen ions and atoms are generated due to the hydrogen-based plasma, if the generated hydrogen diffuses into the base material, there is a possibility that it will lead to hydrogen embrittlement of the base material.

[0008] WC is mainly used in thermal spray coating, but the thermal spray coating method has a problem where the surface becomes rough due to the relatively large particle size of WC, causing quality defects in the rolling electrode. Although the lifespan of the coating layer can be improved by forming a multilayer stack of WC and WC / C layers through the sputtering of acetylene gas (C2H2) and tungsten carbide (WC), the use of hydrocarbon plasma gas generates a large amount of hydrogen ions and atoms, and there is a risk that hydrogen embrittlement may occur if the generated hydrogen diffuses into the base material, and swelling defects may occur if hydrogen molecules are formed.

[0009] Accordingly, there is a need to develop a rolling roll, a method for manufacturing a rolling roll, and a method for manufacturing an electrode using the same, which can prevent the penetration of the plating solution to minimize foreign matter defects and hydrogen defects in the final coating film, while simultaneously improving wear resistance by relatively increasing the hardness of the final coating film.

[0010] The problem to be solved by the present invention is to a rolling roll, a method for manufacturing a rolling roll, and a method for manufacturing an electrode through the same, wherein the maximum length of a crack formed on the surface of the roll base material is 5 μm or less, the rolling roll, the method for manufacturing a rolling roll, and the method for manufacturing an electrode through the same.

[0011] The problems that the present invention aims to solve are not limited to those described above, and problems not mentioned will be clearly understood by those skilled in the art from this specification and the attached drawings.

[0012] A rolling roll according to one embodiment of the present invention comprises: a roll base material; and a chromium-containing plating layer formed on the roll base material, wherein the maximum length of a crack formed on the surface is 5 μm or less.

[0013] The above roll base material may have a surface irregularity portion with a maximum height of 5㎛ or more to 25㎛ or less.

[0014] The above roll base material may include chrome steel.

[0015] The thickness of the chromium-containing plating layer is 100㎛ or more to 150㎛ or less, and the hardness of the chromium-containing plating layer may be 1000Hv or more to 1300Hv or less.

[0016] The residual hydrogen density of the above chromium-containing plating layer is 0.1 ppm / cm² 3 From 0.25 ppm / cm² to 0.25 ppm 3 It may be less than.

[0017] The rolling roll according to the present embodiment further comprises a coating layer formed on the chromium-containing plating layer, and the coating layer may comprise a metal nitride.

[0018] The coating layer may include a chromium nitride layer formed on the chromium-containing plating layer and a titanium nitride layer formed on the chromium nitride layer.

[0019] The coating layer may further include a chromium coating layer located between the chromium-containing plating layer and the chromium nitride layer.

[0020] A rolling roll according to another embodiment of the present invention comprises: a roll base material; a chromium-containing plating layer formed on the roll base material; and a first coating layer formed on the chromium-containing plating layer and comprising titanium nitride.

[0021] The rolling roll according to the present embodiment may further include one or more second coating layers formed between the chromium-containing plating layer and the first coating layer, and comprising chromium or a nitride thereof.

[0022] The thickness of the second coating layer is 0.2 μm or more to 1 μm or less, and the hardness of the second coating layer may be 1000 Hv or more to 2000 Hv or less.

[0023] The first coating layer may include: a first sub-coating layer formed on the chromium-containing plating layer or the second coating layer and comprising titanium nitride (TiN); a second sub-coating layer formed on the first sub-coating layer and comprising titanium-aluminum composite nitride; and a third sub-coating layer formed on the second sub-coating layer and comprising titanium cyanide (TiCN).

[0024] The thickness of the first to third sub-coating layers is each 0.3 μm or more to 1.5 μm or less, and the hardness may increase from the first sub-coating layer to the third sub-coating layer.

[0025] The first sub-coating layer may have a hardness of 2000 Hv or more, the second sub-coating layer may have a hardness of 2500 Hv or more, and the third sub-coating layer may have a hardness of 3000 Hv or more.

[0026] The friction coefficient can be reduced from the first sub-coating layer to the third sub-coating layer.

[0027] The first sub-coating layer may have a friction coefficient of 0.65 to 0.75, the second sub-coating layer may have a friction coefficient of 0.55 to 0.65, and the third sub-coating layer may have a friction coefficient of 0.35 to 0.45.

[0028] The first to third sub-coating layers above are 100 ppm / cm 3 It can have a residual hydrogen density of the following.

[0029] A method for manufacturing a rolling roll according to another embodiment of the present invention comprises the steps of: forming surface irregularities on the surface of a roll base material; forming a chromium-containing plating layer on the roll base material using a plating solution containing a chromium-containing raw material and sulfuric acid; and coating a metal nitride on the chromium-containing plating layer, wherein in the step of forming the chromium-containing plating layer, the plating solution further comprises a sulfonic acid-based organic catalyst, or the plating is carried out while the plating solution is heated to a temperature of 65 degrees Celsius or higher and 90 degrees Celsius or lower.

[0030] The above-mentioned step of forming surface irregularities may include a step of sandblasting or shotblasting the surface of the roll base material.

[0031] The method for manufacturing a rolling roll according to the present embodiment may further include the step of removing residual hydrogen by heat treating at a temperature of 130 degrees or more to 250 degrees or less for a period of 8 hours or more to 40 hours or less after forming the chromium-containing plating layer.

[0032] The method for manufacturing a rolling roll according to the present embodiment may further include a step of polishing and / or cleaning the chromium-containing plating layer between the step of forming the chromium-containing plating layer and the step of coating the metal nitride layer.

[0033] The above chromium-containing raw material includes chromic anhydride, and the above sulfonic acid-based organic catalyst may include an alkyl sulfonate having 1 to 5 carbon atoms.

[0034] The metal nitride layer coating step may include a step of plasma vacuum deposition (sputtering) of the metal nitride.

[0035] The metal nitride layer coating step may include the step of depositing titanium nitride (TiN) on the chromium-containing plating layer; the step of depositing a titanium-aluminum composite nitride on the titanium nitride; and the step of depositing titanium cyanide (TiCN) on the titanium-aluminum composite nitride.

[0036] The method for manufacturing a rolling roll according to the present embodiment may further include a step of coating chromium or chromium nitride on the chromium-containing plating layer between the step of forming the chromium-containing plating layer and the step of coating the metal nitride layer.

[0037] A method for manufacturing a secondary battery according to another embodiment of the present invention comprises the steps of: forming an electrode active material layer on a current collector; and rolling the electrode active material layer with the rolling roll described above.

[0038] According to the embodiments, the rolling roll, the method for manufacturing the rolling roll, and the method for manufacturing the electrode through the same of the present invention include a chromium-containing plating layer having a maximum length of a crack formed on the surface of the roll base material of 5 μm or less, thereby preventing the penetration of the plating solution to minimize foreign matter defects and hydrogen defects in the final coating film, and the hardness of the final coating film is relatively increased, thereby improving wear resistance.

[0039] In addition, the rolling roll, the method for manufacturing a rolling roll, and the method for manufacturing an electrode through the same according to the present invention can improve the lifespan of the coating layer of the rolling roll by forming a plating layer such that the surface of the plating layer does not detach due to rolling load while preventing the plating solution from penetrating into the cracks by applying crack refinement or crack-free plating to the base material of the rolling roll.

[0040] In addition, the rolling roll, the method for manufacturing the rolling roll, and the method for manufacturing the electrode through the same according to the present invention can form a coating layer that improves hardness by depositing a Ti-based nitride on a plating layer, and can secure a level of friction coefficient suitable for rolling and a hardness higher than that of conventional DLC.

[0041] The effects of the present invention are not limited to the effects described above, and unmentioned effects will be clearly understood by those skilled in the art from this specification and the accompanying drawings.

[0042] FIG. 1 is a drawing showing a rolling roll according to one embodiment of the present invention.

[0043] Figures 2 and 3 are enlarged views of the surface of the center of the rolling roll in Figure 1.

[0044] Figure 4 is a magnified view of the surface of the center of the rolling roll of the comparative example.

[0045] FIGS. 5 to 9 are flowcharts illustrating a method for manufacturing a rolling roll according to another embodiment of the present invention.

[0046] FIG. 10 is a flowchart illustrating a method for manufacturing an electrode according to another embodiment of the present invention.

[0047] Figures 11 and 12 are SEM images showing the experimental results according to Experimental Example 1.

[0048] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0049] To clearly explain the present invention, parts unrelated to the explanation have been omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0050] Furthermore, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, and thus the present invention is not necessarily limited to what is illustrated. Thicknesses have been enlarged in the drawings to clearly represent various layers and regions. Additionally, for convenience of explanation, the thickness of some layers and regions has been exaggerated in the drawings.

[0051] Furthermore, throughout the specification, when a part is described as “comprising” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0052] Additionally, throughout the specification, "planar" means when the subject part is viewed from above, and "cross-sectional" means when the cross-section obtained by vertically cutting the subject part is viewed from the side.

[0053] Hereinafter, a rolling roll, a method for manufacturing a rolling roll, and a method for manufacturing an electrode using the same according to the present embodiment will be described in detail.

[0054] FIG. 1 is a drawing showing a rolling roll according to an embodiment of the present invention. FIG. 2 and FIG. 3 are drawings showing an enlarged view of the surface of the center of the rolling roll of FIG. 1.

[0055] Referring to FIGS. 1 and 2, a rolling roll (1000) according to one embodiment of the present invention comprises a roll base material (1100); and a chromium-containing plating layer (1200) formed on the roll base material (1100). Here, the rolling roll (1000) may be a main roll used in a rolling process during the electrode production process of a lithium secondary battery.

[0056] More specifically, the roll base material (1100) may include a central portion (1110) which is a portion for pressing the electrode, and a pair of end portions (1150) integrated with the central portion (1110). However, the shape of the roll base material (1100) is not limited to FIG. 1, and various shapes may be applied as long as they are shapes for pressing the electrode.

[0057] The roll base material (1100) may include chromium steel. More specifically, the roll base material (1100) may be made of high-chromium steel. For example, the roll base material (1100) may be made of 3% chromium steel. In addition, the hardness of the roll base material (1100) may be 700 Hv or more and 800 Hv or less.

[0058] Here, hardness may be the average value of values ​​measured using a Vickers hardness tester. For example, hardness may be the average value of 5 measurements under a load of 300 kgf. Hardness may be described in the same way in the following content.

[0059] The surface of the roll base material (1100) may be modified. More specifically, the surface of the roll base material (1100) may have surface irregularities (1100p) formed after removing foreign substances by a method such as sandblasting or shotblasting. For example, as shown in FIG. 2, the roll base material (1100) may have surface irregularities (1100p) formed thereon with a maximum height of 5㎛ or more to 25㎛ or less. Here, the surface irregularities (1100p) may be formed on the surface of the roll base material (1100) facing the chromium-containing plating layer (1200).

[0060] Accordingly, in the rolling roll (1000) according to the present embodiment, the surface irregularity portion (1100p) formed on the roll base material (1100) has a maximum height of the range described above, thereby expanding the contact area between the roll base material (1100) and the chromium-containing plating layer (1200) to effectively increase adhesion and effectively prevent the chromium-containing plating layer (1200) from detaching from the roll base material (1100).

[0061] In contrast, if the surface irregularity (1100p) is less than 5㎛, it may be difficult to effectively increase the adhesive strength in addition to the self-adhesion between the roll base material (1100) and the chromium-containing plating layer (1200). Furthermore, if the surface irregularity (1100p) is greater than 25㎛, it is difficult to secure a sufficient thickness of the chromium-containing plating layer (1200), and the thickness variation of the chromium-containing plating layer (1200) increases depending on the location of the surface irregularity (1100p), which may lead to a decrease in adhesive strength and the occurrence of surface cracks.

[0062] The chromium-containing plating layer (1200) may have a maximum crack length of 5 μm or less formed on its surface. For example, the crack length may be measured as the average of 10 maximum values ​​confirmed by taking an SEM image of the chromium-containing plating layer (1200) using an electron microscope and then magnifying it to 1500x (unit: μm). This may be explained in the following content as well.

[0063] More specifically, the chromium-containing plating layer (1200) may be a crack-refined or crack-free plating layer when plating with a chromium-containing plating solution containing a chromium-containing raw material (chromium oxide) and sulfuric acid. For example, the crack-refined or crack-free chromium-containing plating layer (1200) may be formed by adding a sulfonic acid-based organic catalyst (such as an alkyl sulfonate) to the chromium-containing plating solution, or by plating the chromium-containing plating solution at a temperature raised to 65°C or higher and 90°C or lower (more preferably, a temperature raised to 70°C or higher and 80°C or lower). Such crack-refined or crack-free plating can make the crack length 5㎛.

[0064] Accordingly, in the rolling roll (1000) according to the present embodiment, the maximum length of the crack formed on the surface of the chromium-containing plating layer (1200) is 5 μm or less, so the maximum length of the crack formed on the surface of the chromium-containing plating layer (1200) is very short compared to the maximum length of the crack in general plating, which is 12 to 15 μm. That is, through this, the rolling roll (1000) according to the present embodiment can prevent the cracks from connecting to each other and can minimize the occurrence of defects caused by cracks. That is, this can drastically reduce the wear of the rolling roll (1000), thereby reducing production costs and reducing the electrode defect rate.

[0065] In contrast, given that the maximum length of cracks in general plating performed on conventional rolling rolls is 12 to 15 μm, long cracks occurring in general plating can be connected to each other in three dimensions, and there is a problem that some of the surface of the plating layer is detached due to the rolling roll load, and subsequent additional coating layers are also peeled off.

[0066] In addition, the thickness of the chromium-containing plating layer (1200) is 100 μm or more to 150 μm or less, and the hardness of the chromium-containing plating layer (1200) can be 1000 Hv or more to 1300 Hv or less.

[0067] Accordingly, in the rolling roll (1000) according to the present embodiment, the hardness is gradually increased in the order of the base material (1100) and the chromium-containing plating layer (1200), thereby effectively preventing a decrease in adhesion due to a sudden change in hardness. In addition, the base material (1100) and the chromium-containing plating layer (1200) contain the same component, thereby providing continuity of components and effectively preventing a decrease in adhesion due to a sudden change in components.

[0068] In addition, the residual hydrogen density after heat treatment of the chromium-containing plating layer (1200) is 0.1 ppm / cm 3 From 0.25 ppm / cm² to 0.25 ppm 3 It may be less than or equal to the following. Here, residual hydrogen density can be measured by Thermal Desorption Spectroscopy (TDS), divided into before and after heat treatment. For example, residual hydrogen density was measured by Thermal Desorption-Gas Chromatography Mass Spectrometry (TD-GC / MS), and may be the value obtained by dividing the amount of hydrogen gas desorbed from the surface of the specimen by the volume of the specimen as the specimens before and after heat treatment were each heated to 80 degrees Celsius.

[0069] More specifically, the chromium-containing plating layer (1200) may be formed on the surface of the roll substrate (1100) through crack refinement or crack-free plating, and then heat-treated for a period of 8 hours or more to 40 hours or less at a temperature of 130 degrees or more to 250 degrees or less. After heat treatment, residual hydrogen contained in the chromium-containing plating layer (1200) is removed, and the residual hydrogen density contained in the chromium-containing plating layer (1200) may be within the range described above.

[0070] Accordingly, in the rolling roll (1000) according to the present embodiment, the chromium-containing plating layer (1200) has the residual hydrogen density described above after heat treatment, thereby preventing residual hydrogen from penetrating into the roll base material (1100) and causing hydrogen embrittlement, and also preventing hydrogen from becoming molecular and causing swelling defects in the coating layer (1300, FIG. 3).

[0071] As shown in FIG. 3, the rolling roll (1000) according to the present embodiment may further include a coating layer (1300) formed on a chromium-containing plating layer (1200). Here, the coating layer (1300) may include a metal nitride. For example, the coating layer (1300) may include a chromium nitride layer (1310) formed on the chromium-containing plating layer (1200) and a titanium nitride layer (1320) formed on the chromium nitride layer (1310). Additionally, the coating layer (1300) may further include a chromium coating layer (1330) located between the chromium-containing plating layer (1200) and the chromium nitride layer (1310).

[0072] The coating layer (1300) will be described in more detail below, and the same description can be applied to this embodiment.

[0073] Referring to FIG. 1 and FIG. 3, a rolling roll (1000) according to another embodiment of the present invention comprises: a roll base material (1100); a chromium-containing plating layer (1200) formed on the roll base material (1100); and a first coating layer (1320) formed on the chromium-containing plating layer (1200) and comprising titanium nitride.

[0074] Here, the chromium-containing plating layer (1200) may be a crack-refined or crack-free plating layer as described above in FIG. 2, or it may be a plating layer according to conventional general crack plating.

[0075] Additionally, the rolling roll (1000) according to the present embodiment may further include one or more second coating layers (1310, 1330) formed between a chromium-containing plating layer (1200) and a first coating layer (1320) and comprising chromium or a nitride thereof. More specifically, the second coating layer (1310, 1330) may refer to a chromium coating layer (1330) and a chromium nitride layer (1310).

[0076] Here, the first coating layer (1320) and the second coating layer (1310, 1330) can be deposited by a plasma method.

[0077] For example, as shown in FIG. 3, in a rolling roll (1000) according to the present embodiment, a chrome coating layer (1330) is positioned between a chrome-containing plating layer (1200) and a chrome nitride layer (1310), and a chrome nitride layer (1310) may be positioned between the chrome coating layer (1330) and a first coating layer (1320).

[0078] The first coating layer (1320) may include a first sub-coating layer (1321) formed on a chromium nitride layer (1310) or a second coating layer (1310, 1330) and comprising titanium nitride (TiN); a second sub-coating layer (1322) formed on the first sub-coating layer (1321) and comprising titanium-aluminum composite nitride; and a third sub-coating layer (1323) formed on the second sub-coating layer (1322) and comprising titanium cyanide (TiCN).

[0079] More specifically, the thickness of the first to third sub-coating layers (1321, 1322, 1323) is 0.3 μm or more to 1.5 μm or less, and the hardness may increase from the first sub-coating layer (1321) to the third sub-coating layer (1323). For example, the first sub-coating layer (1321) may have a hardness of 2000 Hv or more, the second sub-coating layer (1322) may have a hardness of 2500 Hv or more, and the third sub-coating layer (1323) may have a hardness of 3000 Hv or more.

[0080] Accordingly, in the rolling roll (1000) according to the present embodiment, the first coating layer (1320) can have a gradually increasing hardness, which effectively prevents a decrease in adhesion due to a sudden change in hardness, and has the advantage of effectively improving wear resistance as the hardness of the final coating film is 3000 Hv or higher. In addition, the change in hardness is small even after the outermost Ti nitride coating is peeled off, so the rolling roll (1000) can be prevented from wearing out rapidly.

[0081] In addition, the thickness of the second coating layer (1310, 1330) is 0.2 μm or more to 1 μm or less, and the hardness of the second coating layer (1310, 1330) may be 1000 Hv or more to 2000 Hv or less.

[0082] Accordingly, in the rolling roll (1000) according to the present embodiment, the hardness is gradually increased in the order of the chromium-containing plating layer (1200), the second coating layer (1310, 1330), and the first coating layer (1320), so that the decrease in adhesion due to a sudden change in hardness can be effectively prevented.

[0083] In addition, the second coating layer (1310, 1330) contains the same components as the chromium-containing plating layer (1200), thereby providing continuity of components and effectively preventing a decrease in adhesion due to a sudden change in components. Likewise, since the first coating layer (1320) is entirely a titanium nitride layer, continuity of components can also be provided, thereby effectively preventing a decrease in adhesion due to a sudden change in components.

[0084] The friction coefficient may decrease as it goes from the first sub-coating layer (1321) to the third sub-coating layer (1323). Here, the friction coefficient may be an average value measured using a Tribometer. For example, the friction coefficient may be an average value measured using a Tribometer under conditions of a load of 5 N and a speed of 200 rpm. The friction coefficient may be described in the same way in the following content.

[0085] For example, the first sub-coating layer (1321) may have a friction coefficient of 0.65 to 0.75, the second sub-coating layer (1322) may have a friction coefficient of 0.55 to 0.65, and the third sub-coating layer (1323) may have a friction coefficient of 0.35 to 0.45.

[0086] Accordingly, in the rolling roll (1000) according to the present embodiment, since the friction coefficient of the first coating layer (1320) is 0.3 or higher, sufficient adhesion between the coating layers (1300) is secured, and the friction coefficient of the final coating film is secured to a level suitable for rolling, so that the phenomenon of the electrode slipping between the rolling rolls (1000) can be effectively prevented.

[0087] The first to third sub-coating layers (1321, 1322, 1323) are 100 ppm / cm 3 It can have a residual hydrogen density of the following.

[0088] Accordingly, in the rolling roll (1000) according to the present embodiment, the first to third sub-coating layers (1321, 1322, 1323) have the residual hydrogen density described above, thereby preventing residual hydrogen from penetrating into the roll base material (1100) and causing hydrogen embrittlement, and also preventing hydrogen from becoming molecular and causing swelling defects in the coating layer (1300).

[0089]

[0090] Figure 4 is a magnified view of the surface of the center of the rolling roll of the comparative example.

[0091] Referring to FIG. 4, a rolling roll according to a comparative example includes a roll base material (1100'); a general hard chrome plating layer (1200') formed on the roll base material (1100'); a chrome nitride layer (1300') formed on the general hard chrome plating layer (1200'); and a DLC (Diamond Like Coating) coating layer (1400').

[0092] Here, the roll base material (1100') may be made of high-chromium steel having a hardness of 700 Hv or more to 800 Hv or less. Additionally, the general hard chrome plating layer (1200') may have a thickness of 100 μm or more to 150 μm or less and a hardness of 800 Hv or more to 1000 Hv or less. Additionally, the chromium nitride layer (1300') may have a thickness of 0.1 μm or more to 1.0 μm or less and a hardness of 1500 Hv or more to 1900 Hv or less. Additionally, the DLC coating layer (1400') may have a thickness of 1 μm or more to 2 μm or less, a hardness of 2000 Hv, and a friction coefficient of 0.05 or more to 0.2 or less.

[0093] At this time, the general hard chrome plating layer (1200') has a problem in that, as described above, the maximum length of the cracks is 12 to 15 μm, and such long cracks can be connected to each other in three dimensions, and some of the surface of the plating layer is detached by the rolling roll load, and subsequent additional coating layers are also peeled off.

[0094] In addition, since the DLC coating layer (1400') is generally formed through an ion beam deposition method using a carbon-hydrogen-based plasma gas, the generated hydrogen atoms become hydrogen molecules and aggregate to form bubbles, leading to blister-type defects, which causes the coating layer to peel off. Furthermore, as described above, the hardness of the DLC coating layer (1400') is limited to 2,000 Hv, so it may not be sufficient to ensure the wear resistance of the rolling roll. In addition, the DLC coating layer (1400') has an excessively low friction coefficient (0.05 to 0.2), and as the adhesion with the roll base material (1100') is insufficient, a buffer layer such as a chromium nitride layer (1300') between the DLC coating layer (1400') and the roll base material (1100') is inevitably required.

[0095] In contrast, as shown in FIGS. 1 to 3, the rolling roll (1000) according to the present embodiment has a maximum length of 5㎛ or less for a crack formed on the surface of a chromium-containing plating layer (1200), thereby minimizing defects caused by cracks and significantly reducing wear of the rolling roll (1000), which can reduce production costs and reduce the electrode defect rate.

[0096] In addition, the rolling roll (1000) according to the present embodiment can effectively extend the lifespan of the rolling roll by reducing friction with an electrode containing an active material that causes wear, by depositing a first coating layer (1320) containing a titanium-based nitride (TiN, TiCN, TiAlCN) having a low residual hydrogen density, high hardness, and a relatively high friction coefficient by a plasma method.

[0097] Hereinafter, a method for manufacturing a rolling roll according to another embodiment of the present invention will be described.

[0098] FIGS. 5 to 9 are flowcharts illustrating a method for manufacturing a rolling roll according to another embodiment of the present invention.

[0099] Referring to FIG. 3 and FIG. 5, a method for manufacturing a rolling roll according to another embodiment of the present invention comprises the steps of: forming a surface irregularity portion (1100p) on the surface of a roll base material (1100) (S100); forming a chromium-containing plating layer (1200) on the roll base material (1100) using a plating solution containing a chromium-containing raw material and sulfuric acid (S200); and coating a metal nitride layer (1320) on the chromium-containing plating layer (1200).

[0100] Referring to FIGS. 3 and 6, the surface roughness formation step (S100) may include a step of sandblasting or shotblasting the surface of the roll base material (1100). Additionally, after step (S110), a step (S120) of cleaning the surface of the roll base material (1100) may also be additionally performed.

[0101] In the step of forming a chromium-containing plating layer (S200), the chromium-containing raw material may include chromic anhydride.

[0102] Additionally, the step of forming a chromium-containing plating layer (S200) may involve adding a sulfonic acid-based organic catalyst to the chromium-containing plating solution, or performing crack refinement or crack-free plating while the chromium-containing plating solution is heated to a temperature of 65°C or higher to 90°C or lower (more preferably 70°C or higher to 80°C or lower). At this time, the sulfonic acid-based organic catalyst may include an alkyl sulfonate having 1 to 5 carbon atoms.

[0103] Referring to FIGS. 3, 5, and 7, the method for manufacturing a rolling roll according to the present embodiment may further include a step (S400) of removing residual hydrogen by heat treating at a temperature of 130°C or higher to 250°C or lower for a period of 8 hours or more to 40 hours or less after forming a chromium-containing plating layer (S200). More specifically, step (S400) may be performed between step (S200) and step (S300). At this time, the heating temperature for hydrogen removal is 140°C or higher to 200°C or lower, and the holding time is 10 hours or more to 30 hours or less. Afterward, cooling is performed by furnace cooling and is cooled until the temperature reaches 50°C or lower.

[0104] Additionally, between the step of forming a chromium-containing plating layer (S200) and the step of coating a metal nitride layer (S300), a step (S500, S600) of polishing and / or cleaning the chromium-containing plating layer (1200) may be further included. More specifically, the step (S500, S600) may be performed additionally after the step (S400). At this time, the step (S500) may be adjusted so that the friction coefficient does not exceed 0.7 by securing surface roughness through surface polishing after the hydrogen removal heat treatment step (S400). Also, after (S500), the step (S600) may be performed so that the surface of the rolling roll (1000) is cleaned with ultrasound or plasma to clean the surface, and then the final step of coating a metal nitride layer (S300) may be performed.

[0105] The metal nitride layer coating step (S300) may include a step of plasma vacuum deposition (sputtering) of the metal nitride. More specifically, referring to FIGS. 3 and FIGS. 8, the metal nitride layer coating step (S300) may include a step (S310) of depositing titanium nitride (TiN) on a chromium-containing plating layer (1200); a step (S320) of depositing a titanium-aluminum composite nitride on the titanium nitride; and a step (S330) of depositing titanium cyanide (TiCN) on the titanium-aluminum composite nitride.

[0106] Referring to FIG. 3 and FIG. 9, the method for manufacturing a rolling roll according to the present embodiment may further include a step of coating chromium or chromium nitride on the chromium-containing plating layer (S340, S350) between the step of forming a chromium-containing plating layer (S200) and the step of coating a metal nitride layer (S300). More specifically, as shown in FIG. 9, after the step of forming a chromium-containing plating layer (S200), a step of depositing chromium on the chromium-containing plating layer (S340) and a step of depositing chromium nitride on the chromium coating layer (S350) may be additionally performed.

[0107] Accordingly, the method for manufacturing a rolling roll according to the present embodiment has the advantage of forming a chromium-containing plating layer through crack refinement or crack-free plating in the step (S200) of forming a chromium-containing plating layer, thereby preventing the penetration of the plating solution due to cracks, fundamentally blocking foreign defects flowing out from hair cracks during the heat treatment process, and improving the yield rate of the plasma coating process. In addition, the chromium-containing plating layer formed through crack refinement or crack-free plating can increase the hardness to 1,000 to 1,300 Hv, thereby preventing rapid wear even after the outermost Ti nitride coating is peeled off.

[0108] In addition, the rolling roll manufacturing method according to the present embodiment can reduce wear on the roll by lowering the friction coefficient to a level of 0.4 to 0.7 and gradually increasing the hardness to a maximum of 3,500 Hv through the deposition of a Ti-based nitride in the metal nitride layer coating step (S300), and can fundamentally prevent peeling of the coating layer due to swelling defects caused by hydrogen generation, thereby significantly extending the lifespan of the rolling roll (1000). That is, the rolling roll manufacturing method according to the present embodiment can extend the replacement cycle of the rolling roll (1000), thereby reducing production costs and improving the rolling productivity of stable electrode active materials.

[0109] FIG. 10 is a flowchart illustrating a method for manufacturing an electrode according to another embodiment of the present invention.

[0110] Referring to FIG. 10, a method for manufacturing a secondary battery according to another embodiment of the present invention includes the step of forming an electrode active material layer on a current collector (S700); and the step of rolling the electrode active material layer with a rolling roll (1000) (S800).

[0111] Accordingly, the secondary battery manufacturing method according to the present embodiment has the advantage of being able to manufacture a secondary battery by rolling the electrode active material layer with a rolling roll (1000) having a relatively long lifespan, thereby reducing the production cost of the secondary battery while improving productivity.

[0112]

[0113] The content of the present invention is explained below through more specific embodiments, but the following embodiments are intended to illustrate the invention and the scope of the invention is not limited thereto.

[0114]

[0115] <Example 1>

[0116] First, a high-strength steel base material of SKD11 with dimensions of 40 mmL x 20 mmW x 10 mmH was used. The surface of this roll base material was sandblasted using aluminum oxide (Al2O3) with an average particle size of about 90 μm as an abrasive, so that the average surface roughness (Ra) was reduced to about 3 μm. Subsequently, the surface was cleaned by spraying pure water at 20 to 25 degrees Celsius (room temperature) over the entire surface three times for 15 minutes on the sandblasted surface of the roll base material.

[0117] Meanwhile, an aqueous solution containing 200 g / L of chromic anhydride, 25 g / L of sulfuric acid, and 10 g / L of ethyl sulfonate catalyst was prepared and used as a plating solution. At this time, the temperature of the plating solution was maintained at 50 degrees Celsius.

[0118] The roll base material was immersed in the plating solution and electroplated at 50 degrees Celsius to form a chromium-containing plating layer having a thickness of 100 to 200 μm on the surface of the roll base material.

[0119]

[0120] <Example 2>

[0121] In the same manner as in Example 1, a chromium-containing plating layer was formed on a roll substrate, and then heat-treated for 8 hours or more to 40 hours or less at a temperature of 130 degrees or more to 250 degrees or less to remove residual hydrogen.

[0122]

[0123] <Example 3>

[0124] In the same manner as in Example 1, a chromium-containing plating layer was formed on a roll substrate, and then a chromium nitride (CrN) coating layer with a thickness of 0.3 to 0.5 μm, a titanium nitride (TiN) coating layer with a thickness of 0.5 to 1.0 μm, a titanium-aluminum composite nitride (TiAlN) coating layer with a thickness of 0.5 to 1.0 μm, and a titanium cyanide (TiCN) coating layer with a thickness of 0.5 to 1.0 μm were sequentially deposited on the chromium-containing plating layer using a plasma vacuum (sputtering) method.

[0125] At this time, sputtering was performed in a vacuum under conditions where there was a heater that generated heat at a temperature of 80 degrees or more to 200 degrees or less.

[0126]

[0127] <Comparative Example 1>

[0128] First, a high-strength steel base material of SKD11 with dimensions of 40mmL x 20mmW x 10mmH was used.

[0129] Meanwhile, an aqueous solution containing 200 g / L of chromic anhydride and 25 g / L of sulfuric acid was prepared and used as a plating solution. At this time, the temperature of the plating solution was maintained at 50 degrees Celsius.

[0130] The roll base material was immersed in the plating solution and electroplated at 50 degrees Celsius to form a chromium-containing plating layer having a thickness of 100 to 200 μm on the surface of the roll base material.

[0131]

[0132] <Comparative Example 2>

[0133] In the same manner as Comparative Example 1, a chromium-containing plating layer was formed on a roll substrate, and then heat-treated for 8 hours or more to 40 hours or less at a temperature of 130 degrees or more to 250 degrees or less to remove residual hydrogen.

[0134]

[0135] <Comparative Example 3>

[0136] A buffer layer (CrN) with a thickness of 0.1 to 1.0 μm was deposited on the chromium-containing plating layer of Comparative Example 1, and then a DLC coating with a thickness of 1.5 to 2.5 μm was applied. Here, the DLC coating can be applied using a hydrocarbon-based (CnHn) plasma gas.

[0137]

[0138] <Experimental Example 1_SEM Image Capture and Crack Size Verification>

[0139] SEM images were taken of the chromium-containing plating layers of Example 1 and Comparative Example 1 using an electron microscope. Fig. 11 is an SEM image of Example 1, and Fig. 12 is an SEM image of Comparative Example 1.

[0140] Specifically, the cross-sections of the samples prepared in Example 1 and Comparative Example 1 were examined by magnifying them with an SEM at 1500x magnification (unit: μm), and the average of the 10 confirmed maximum values ​​was calculated as the representative value.

[0141] Referring to FIGS. 11 and 12, it can be seen that in Example 1, the length of most cracks is 5 μm or less, whereas in Comparative Example 1, cracks with a length of 10 μm or more occur.

[0142] Accordingly, unlike Comparative Example 1, it can be confirmed that the crack length is effectively reduced by using an alkyl sulfonate-based catalyst in the plating solution as in Example 1. That is, compared to Comparative Example 1, defects caused by cracks can be effectively prevented in the case of Example 1.

[0143]

[0144] <Experimental Example 2_ Measurement of Hydrogen Content, Residual Hydrogen Mass Ratio, and Hardness of Chromium-Containing Plating Layer>

[0145] The residual hydrogen density and hardness of the chromium-containing plating layers for Example 1, Example 2, Comparative Example 1, and Comparative Example 2 were measured, respectively, and the results are shown in Table 1.

[0146] The amount of hydrogen was measured by thermal desorption-gas chromatography mass spectrometry (TD-GC / MS), and the hydrogen gas desorbed from the surface of the specimens of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 was measured as the specimens were heated to 80 degrees Celsius. The residual hydrogen mass ratio is the value obtained by dividing the previously measured amount of hydrogen by the weight of the specimen.

[0147] Hardness was measured using a Vickers hardness tester and was calculated as the average of 5 measurements under a load of 300 kgf.

[0148] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Specimen Weight (g) 58.1 57.7 58.9 58.8 Hydrogen Content (μg) 71 4.6 18 8.7 54 1.9 8 7.6 Residual Hydrogen Mass Ratio (Hydrogen Content / Specimen Weight, wppm) 12.3 3.2 79.2 1.49 Hardness (Hv) 90 69 32 88 0895

[0149] Referring to the results of the hydrogen amount and residual hydrogen mass ratio in Table 1, when comparing Example 1 and Comparative Example 1, it can be seen that a relatively large amount of hydrogen is detached from the surface of the chromium-containing plating layer in Example 1 compared to Comparative Example 1. Additionally, when comparing Example 2 and Comparative Example 2, it can be seen that a relatively large amount of hydrogen is detached from the surface of the chromium-containing plating layer in Example 2 compared to Comparative Example 2.

[0150] As such, it can be confirmed that in the chromium-containing plating layer prepared as in Example 1 and Example 2, the amount of hydrogen detached or removed from the surface of the chromium-containing plating layer is relatively large compared to the chromium-containing plating layer prepared as in Comparative Example 1 and Comparative Example 2.

[0151] When comparing Example 2 with Example 1, it can be seen that a relatively smaller amount of hydrogen is detached from the surface of the chromium-containing plating layer in Example 2 compared to Example 1. Additionally, when comparing Comparative Example 2 with Comparative Example 1, it can be seen that a relatively smaller amount of hydrogen is detached from the surface of the chromium-containing plating layer in Comparative Example 2 compared to Comparative Example 1.

[0152] As such, it can be confirmed that, as in Example 2 and Comparative Example 2, some of the hydrogen already contained in the chromium-containing plating layer is removed through the heat treatment process, and the amount of hydrogen detached or removed from the surface of the chromium-containing plating layer is reduced compared to Example 1 and Comparative Example 1, respectively.

[0153] Referring to the hardness results in Table 1, when comparing Example 1 and Comparative Example 1, it can be seen that the hardness of the chromium-containing layer in Example 1 is relatively greater than that in Comparative Example 1. Additionally, when comparing Example 2 and Comparative Example 2, it can be seen that the hardness of the chromium-containing layer in Example 2 is relatively greater than that in Comparative Example 2.

[0154] As such, it can be confirmed that the chromium-containing plating layer prepared as in Example 1 and Example 2 has a greater hardness than the chromium-containing plating layer prepared as in Comparative Example 1 and Comparative Example 2. This is because, when referring to the experimental results of Experimental Example 1, Example 1 minimizes plating defects as cracks of smaller length are formed compared to Comparative Example 1, and through this, it can be confirmed that the hardness of the chromium-containing plating layer of Example 1 is greater than that of Comparative Example 1. This can be explained in the same way for Example 2.

[0155] When comparing Example 2 with Example 1, it can be seen that the chromium-containing plating layer in Example 2 has a relatively higher hardness compared to Example 1. In addition, when comparing Comparative Example 2 with Comparative Example 1, it can be seen that the chromium-containing plating layer in Comparative Example 2 has a relatively higher hardness compared to Comparative Example 1.

[0156] In this way, coating defects can be minimized as hydrogen already contained in the chromium-containing plating layer is partially removed through a heat treatment process as in Example 2 and Comparative Example 2, and through this, it can be confirmed that the hardness of the chromium-containing plating layer in Example 2 and Comparative Example 2 is greater than that of Example 1 and Comparative Example 1, respectively.

[0157]

[0158] <Experimental Example 3_ Measurement of Residual Hydrogen Density, Hardness, Friction Coefficient, and Adhesion of Coating Layer>

[0159] The residual hydrogen density, hardness, friction coefficient, and adhesion of the coating layer for Example 3 and Comparative Example 3 were measured, and the results are shown in Table 2.

[0160] The residual hydrogen density was measured by thermal desorption-gas chromatography mass spectrometry (TD-GC / MS), and may be the value obtained by dividing the amount of hydrogen gas desorbed from the surface of the specimens of Example 3 and Comparative Example 3 by the volume of the specimens as the specimens were heated to 80 degrees Celsius.

[0161] Hardness was measured using a Vickers hardness tester as the average of 5 values ​​under a load of 300 kgf.

[0162] The coefficient of friction was measured using a Tribometer under conditions of a load of 5N and a speed of 200rpm.

[0163] Adhesion strength was measured by a scratch test, and the force at which peeling occurs was measured while increasing the pressing force. In the case of Comparative Example 3, it was measured under conditions of a load of 0.5 to 30 N and a speed of 0.55 mm / sec, and in the case of Example 3, it was measured under conditions of a load of 1 to 60 N and a speed of 0.55 mm / sec.

[0164] Comparative Example 3 Example 3 DLC coating layer CrN coating layer TiN coating layer TiAlN coating layer TiCN coating layer Residual hydrogen density (ppm / cm²) 3 Hardness (Hv) 2,000 1,500~1,900 2,000~2,500 2,500~3,000 3,000~3,500 Coefficient of Friction 0.0 5 0.4 0.7 0.6 0.4 Adhesion (N) 17.8 30 30 30 30

[0165] Referring to Table 2, it can be seen that the residual hydrogen density of the DLC coating layer of Comparative Example 3 is 690 ppm / cm3, whereas in the case of Example 3, the residual hydrogen density is 0 in each coating layer. In particular, since swelling defects caused by residual hydrogen occur when the hydrogen density is 500 ppm / cm3 or higher, such swelling defects occur in the case of Comparative Example 3, whereas swelling defects can be effectively prevented in the case of Example 3.

[0166] In addition, while the hardness of the DLC coating layer of Comparative Example 3 is 2,000 Hv, it can be seen that the hardness of the coating layer of Example 2 gradually increases in the order of chromium nitride (CrN) coating layer, titanium nitride (TiN) coating layer, titanium-aluminum composite nitride (TiAlN) coating layer, and titanium cyanide (TiCN) coating layer.

[0167] In addition, it can be confirmed that the friction coefficient of Comparative Example 3 is 0.05, whereas the coating layer of Example 3 has a friction coefficient of 0.4 to 0.7. Generally, if the friction coefficient is 0.1 or less, a slip phenomenon of the electrode occurs between the rolls during rolling; in the case of Comparative Example 3, such a slip phenomenon occurs, whereas in the case of Example 2, the occurrence of the slip phenomenon can be effectively prevented.

[0168] In addition, it can be seen that the adhesion strength of Comparative Example 3 is 17.8 N, whereas the adhesion strength of Example 3 is 30 N. That is, in the case of Example 3, due to the high adhesion strength, peeling of each coating layer hardly occurs, whereas in the case of Comparative Example 3, due to the lower adhesion strength compared to Example 3, peeling of the coating layer occurs easily.

[0169] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

[0170] [Explanation of the symbol]

[0171] 1000: Rolled roll

[0172] 1100: Roll base material

[0173] 1200: Chromium-containing plating layer

[0174] 1300: Coating layer

Claims

1. Roll base material; and A rolling roll comprising a chromium-containing plating layer formed on the above-mentioned roll base material, wherein the maximum length of a crack formed on the surface is 5 μm or less.

2. In Paragraph 1, The above roll base material is a rolling roll having a surface irregularity portion with a maximum height of 5㎛ or more to 25㎛ or less.

3. In Paragraph 1, The above roll base material is a rolling roll containing chrome steel.

4. In Paragraph 1, The thickness of the chromium-containing plating layer is 100㎛ or more to 150㎛ or less, and A rolling roll having a chromium-containing plating layer with a hardness of 1000 Hv or more and 1300 Hv or less.

5. In Paragraph 1, The residual hydrogen density of the above chromium-containing plating layer is 0.1 ppm / cm² 3 From 0.25 ppm / cm² to 0.25 ppm 3 Rolling rolls under one year.

6. In Paragraph 1, It further includes a coating layer formed on the chromium-containing plating layer, and The above coating layer is a rolling roll containing a metal nitride.

7. In Paragraph 6, The above coating layer comprises a chromium nitride layer formed on the chromium-containing plating layer and a titanium nitride layer formed on the chromium nitride layer, forming a rolling roll.

8. In Paragraph 6, The above coating layer further comprises a chrome coating layer located between the chrome-containing plating layer and the chrome nitride layer, forming a rolling roll.

9. Roll base material; A chromium-containing plating layer formed on the above-mentioned roll base material; A rolling roll comprising a first coating layer formed on the above-mentioned chromium-containing plating layer and comprising titanium nitride.

10. In Paragraph 9, A rolling roll further comprising one or more second coating layers formed between the chromium-containing plating layer and the first coating layer, and comprising chromium or a nitride thereof.

11. In Paragraph 10, The thickness of the second coating layer is 0.2 μm or more to 1 μm or less, and A rolling roll having a hardness of 1000 Hv or more and 2000 Hv or less of the second coating layer.

12. In Paragraph 9 or 10, The first coating layer above is, A first sub-coating layer formed on the chromium-containing plating layer or the second coating layer and comprising titanium nitride (TiN); A second sub-coating layer formed on the first sub-coating layer and comprising a titanium-aluminum composite nitride; and A rolling roll comprising a third sub-coating layer formed on the second sub-coating layer and comprising titanium cyanide (TiCN).

13. In Paragraph 12, The thickness of the first to third sub-coating layers each has a thickness of 0.3 μm or more to 1.5 μm or less, and A rolling roll having increased hardness from the first sub-coating layer to the third sub-coating layer.

14. In Paragraph 13, The first sub-coating layer has a hardness of 2000 Hv or more, and The above second sub-coating layer has a hardness of 2500 Hv or more, and The above third sub-coating layer is a rolling roll having a hardness of 3000 Hv or more.

15. In Paragraph 12, A rolling roll having a friction coefficient that decreases from the first sub-coating layer to the third sub-coating layer.

16. In Paragraph 15, The first sub-coating layer has a friction coefficient of 0.65 to 0.75, and The second sub-coating layer has a friction coefficient of 0.55 to 0.65, and The above third sub-coating layer is a rolling roll having a friction coefficient of 0.35 to 0.

45.

17. In Paragraph 12, The first to third sub-coating layers above are 100 ppm / cm 3 Rolling roll having a residual hydrogen density of the following.

18. A step of forming surface irregularities on the surface of the roll base material; A step of forming a chromium-containing plating layer on the roll substrate using a plating solution containing a chromium-containing raw material and sulfuric acid; and The method includes the step of coating a metal nitride layer on the chromium-containing plating layer, and A method for manufacturing a rolling roll, wherein in the step of forming a chromium-containing plating layer, the plating solution further comprises a sulfonic acid-based organic catalyst, or the plating is carried out while the plating solution is heated to a temperature of 65 degrees Celsius or higher and 90 degrees Celsius or lower.

19. In Paragraph 18, A method for manufacturing a rolling roll, comprising the step of forming the surface irregularities above, which involves sandblasting or shotblasting the surface of the roll base material.

20. In Paragraph 18, A method for manufacturing a rolling roll, further comprising the step of removing residual hydrogen by heat treating at a temperature of 130 degrees or more to 250 degrees or less for a period of 8 hours or more to 40 hours or less after forming the chromium-containing plating layer.

21. In Paragraph 18, A method for manufacturing a rolling roll, further comprising a step of performing at least one of polishing and cleaning the chromium-containing plating layer between the step of forming the chromium-containing plating layer and the step of coating the metal nitride layer.

22. In Paragraph 18, The above chromium-containing raw material includes chromic anhydride, and A method for manufacturing a rolling roll comprising an alkyl sulfonate having 1 to 5 carbon atoms, wherein the above sulfonic acid-based organic catalyst comprises 23. In Paragraph 18, A method for manufacturing a rolling roll, comprising the step of coating a metal nitride layer, wherein the metal nitride is plasma vacuum deposited (sputtered).

24. In Paragraph 18, The above metal nitride layer coating step is, A step of depositing titanium nitride (TiN) on the chromium-containing plating layer; A step of depositing a titanium-aluminum composite nitride on the titanium nitride; and A method for manufacturing a rolling roll comprising the step of depositing titanium cyanide (TiCN) on the titanium-aluminum composite nitride.

25. A method for manufacturing a rolling roll according to claim 24, further comprising, between the step of forming a chromium-containing plating layer and the step of coating a metal nitride layer, a step of coating chromium or chromium nitride on the chromium-containing plating layer.

26. A step of forming an electrode active material layer on a current collector; and A method for manufacturing an electrode of a secondary battery comprising the step of rolling the electrode active material layer with a rolling roll according to claim 1 or claim 9.

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