Electrode sheet calender roll including hard layer formed by physical vapor deposition and method of manufacturing the same

Abstract

Disclosed is an electrode sheet calender roll including a hard layer formed by physical vapor deposition and a manufacturing method thereof. The manufacturing method of the electrode sheet calender roll according to one embodiment of the present invention is characterized by including: a hard layer forming step of forming a hard layer on a roll core composed of a steel material containing carbon by a PVD method; and a hard layer forming step of polishing the hard layer so that the thickness of the hard layer is different between a center portion and end portions of the calender roll.

Description

Technical Field

[0001] This invention relates to an electrode calendering roll comprising a hard layer formed by physical vapor deposition (PVD) and a method thereof. Specifically, this invention relates to an electrode calendering roll and a method thereof, the electrode calendering roll comprising a hard layer formed by PVD as an environmentally friendly method, without using materials that pollute the environment or are harmful to human health. Background Technology

[0002] Typically, the electrodes of a secondary battery are manufactured by coating an electrode material onto an electrode sheet. In order to improve the capacity density of the electrode, increase the adhesion between the electrode current collector and the electrode material, and form the electrode to the target thickness, the electrode sheet coated with the electrode material is subjected to a calendering process.

[0003] In addition, the rolls used for rolling electrode sheets are usually made of bearing steel. To improve the wear resistance of the rolls and extend their service life, a Cr coating is sometimes formed using a wet method.

[0004] However, when forming a Cr coating using a wet method, Cr must be used. 6+ Additionally, Cr 6+ It is a highly toxic carcinogen, and long-term exposure may also induce respiratory diseases, dermatitis, kidney damage, and liver damage. Furthermore, Cr... 6+ It will also have adverse effects on aquatic life and become a source of soil and water pollution.

[0005] Therefore, based on environmental regulations in various countries around the world, it is expected that the use of Cr will be banned in the future. 6+ And currently using C r6+ However, there is also the problem of increased costs due to environmental taxes and fees.

[0006] Therefore, there is a growing demand for calender rolls and their manufacturing methods that are both environmentally friendly and promote improved wear resistance and extended lifespan in the production of electrode sheet calender rolls. Summary of the Invention

[0007] (a) Technical problems to be solved In order to solve the problems of the prior art, the present invention aims to provide an electrode sheet calendering roll with a hard layer formed by physical vapor deposition (PVD) and a method thereof.

[0008] However, the technical problem to be solved by the embodiments of the present invention is not limited to the technical problem described above, and other technical problems may also exist.

[0009] (II) Technical Solution As a technical solution for solving the above-mentioned technical problems, a method for manufacturing an electrode sheet calendering roll including a hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention is characterized by comprising: a hard layer forming step, forming a hard layer on a roll core composed of carbon-containing steel by PVD method; and a hard layer grinding step, grinding the hard layer so that the thickness of the hard layer is different at the center and the ends of the calendering roll.

[0010] Furthermore, the hard layer forming step may include: a first hard layer deposition step, in which a first hard layer composed of a material selected from Cr, W, and Ti is deposited; and a second hard layer deposition step, in which a first hard layer composed of a material selected from Cr is deposited. x N y (x and y are numbers between 0 and 1), Cr x O y A second hard layer composed of materials such as CrC, WC, TiN, and TiC is deposited (x and y are numbers between 0 and 1).

[0011] Furthermore, in the hard layer formation step, after the first hard layer deposition step and the second hard layer deposition step, a third hard layer deposition step may be included, whereby a third hard layer is deposited on the second hard layer. The third hard layer may be composed of materials selected from Cr, W, Ti, and Cr. x N y Cr x O y Material composition in CrC, WC, TiN and TiC.

[0012] Furthermore, the hard layer formation step can be achieved by using sputtering or arc deposition methods in PVD to deposit Cr, W, Ti, and Cr. x N y (x and y are numbers between 0 and 1), Cr x O y (x and y are numbers between 0 and 1), CrC, WC, TiN or TiC are deposited on the roller core.

[0013] In addition, the hard layer grinding step may include the following steps: performing a grinding such that the thickness of the hard layer at the end of the calender roll is thinner than the thickness of the hard layer at the center of the calender roll; and performing mirror grinding such that the surface roughness of the hard layer is lower than a specified value.

[0014] Furthermore, the method for manufacturing the electrode sheet calendering roll may further include a coating forming step, which forms a coating on the hard layer, after the hard layer grinding step.

[0015] Furthermore, the coating formation step may further include: a buffer layer formation step, forming at least one buffer layer by coating a metallic material; and a diamond-like carbon (DLC) layer formation step, forming the diamond-like carbon (DLC) layer by ion beam deposition or chemical vapor deposition (CVD) methods.

[0016] An electrode sheet calendering roll according to an embodiment of the present invention, comprising a hard layer formed by physical vapor deposition (PVD), is characterized in that it includes: a roll core composed of carbon-containing steel; and a hard layer formed on the roll core by a PVD method, wherein, in the hard layer, the hard layer at the center and the ends of the calendering roll is formed to different thicknesses by grinding.

[0017] Furthermore, the thickness of the hard layer can be such that the thickness of the hard layer at the end of the calender roll is thinner than the thickness of the hard layer at the center of the calender roll.

[0018] Furthermore, the hard layer may include: a first hard layer composed of a material selected from Cr, W, and Ti; and a second hard layer composed of a material selected from Cr. x N y (x and y are numbers between 0 and 1), Cr x O y (x and y are numbers between 0 and 1), material composition in CrC, WC, TiN and TiC.

[0019] The above technical solutions are merely exemplary and should not be construed as limiting the present invention. In addition to the exemplary embodiments described above, there may be additional embodiments illustrated in the accompanying drawings and specification.

[0020] (III) Beneficial Effects According to the technical solution of the present invention, a hard layer is formed by an environmentally friendly method, which can solve environmental problems and not only prevent cost increases caused by environmental taxes and fees, but also provide an electrode sheet calendering roll and its manufacturing method that can promote the improvement of the wear resistance and extend the service life of the calendering roll.

[0021] Furthermore, according to the above-described technical solution of the present invention, an electrode sheet calendering roll and its manufacturing method can be provided. Since the dehydrogenation treatment for removing hydrogen (H) and metal hydroxides (e.g., hydrogen chromate (H2CrO4 or H2Cr2O7)) that inevitably occur inside the coating during wet plating can be omitted, the grinding of the hard layer can be performed continuously, thereby improving productivity and fundamentally preventing plating gassing defects that may occur after the dehydrogenation treatment.

[0022] However, the effects that can be obtained by the present invention are not limited to the above-mentioned effects, and other effects may also exist. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention.

[0024] Figure 2 This is a flowchart illustrating an embodiment of a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention.

[0025] Figure 3 This is a flowchart illustrating, specifically, an embodiment of a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention, in the hard layer forming step, which includes a plurality of hard layers.

[0026] Figure 4 This is a flowchart illustrating a specific embodiment of a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention, specifically showing a hard layer grinding step in one of the embodiments of the present invention.

[0027] Figure 5 This is a flowchart illustrating a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) according to another embodiment of the present invention.

[0028] Figure 6 This is a flowchart illustrating an embodiment of a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) according to another embodiment of the invention.

[0029] Figure 7 This is a side cross-sectional view of an electrode sheet calendering roll including a hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention.

[0030] Figure 8 (a) is a cross-sectional view of the center portion of an electrode sheet calendering roll comprising a single hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention. Figure 8 (b) is a cross-sectional view of the end of an electrode sheet calendering roll comprising a single hard layer according to an embodiment of the present invention.

[0031] Figure 9 (a) is a cross-sectional view of the center portion of an electrode sheet calendering roll comprising multiple hard layers formed by physical vapor deposition (PVD) according to an embodiment of the present invention. Figure 9 (b) is a cross-sectional view of the end of an electrode sheet calendering roll comprising a plurality of hard layers according to an embodiment of the present invention.

[0032] Figure 10 (a) is a cross-sectional view of the central portion of an electrode sheet calendering roll comprising a single hard layer and a coating formed by physical vapor deposition (PVD) according to another embodiment of the invention. Figure 10 (b) is a cross-sectional view of the end of an electrode sheet calendering roll comprising a single hard layer and a coating according to another embodiment of the invention.

[0033] [Explanation of reference numerals in the attached figures] 100: Electrode sheet calendering roll including a hard layer formed by physical vapor deposition 10: Roller core 20: Hard layer 20A: First hard layer 20B: Second hard layer 20C: Third hard layer 21: Area 1 22: Second Zone 30: Buffer layer 31: First Buffer Layer 32: Second Buffer Layer 40: DLC Layer S112A: First hard layer deposition step S112C: Second hard layer deposition step Detailed Implementation

[0034] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art can readily implement the invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Furthermore, for clarity of explanation, parts irrelevant to the description have been omitted from the drawings, and similar reference numerals have been used throughout the specification for similar parts.

[0035] In the entire specification of this invention, when describing a part as being "connected" to other parts, this includes not only the case of "direct connection" but also the case of "electrical connection" or "indirect connection" by setting other elements in between.

[0036] In the entire specification of this invention, when describing a component as being "above," "upper," "upper end," "below," "lower," or "lower end" of other components, this includes not only the case where a component is connected to other components, but also the case where there is another component between two components.

[0037] Throughout the entire specification of this invention, unless otherwise specifically stated to the contrary, a description of a part as "comprising" or "including" a constituent element means that it may also include other constituent elements, rather than excluding other constituent elements.

[0038] The present invention relates to a calender roll comprising a hard layer formed by physical vapor deposition (PVD) and a method thereof for manufacturing the same, which can prevent adverse environmental impacts.

[0039] Figure 1 This is a flowchart illustrating a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention.

[0040] Reference Figure 1 According to one embodiment of the present invention, the method S100 for manufacturing an electrode sheet calendering roll may include a hard layer forming step S110, in which a hard layer is formed on a roll core composed of carbon-containing steel by a PVD method.

[0041] The roller core can be made of carbon-containing steel, for example, bearing steel containing carbon and manganese. Furthermore, the roller core can be formed in a cylindrical shape.

[0042] PVD is a dry deposition method, which refers to a deposition method that uses only gas and no liquid.

[0043] The hard layer formed by the PVD method can be composed of metallic materials, such as chromium (Cr), tungsten (W), or titanium (Ti). Alternatively, the hard layer can be composed of chromium oxide (Cr) in addition to the aforementioned metals. x O y Metal oxides such as chromium nitrides (Cr) x N yIt is formed from metal nitrides such as titanium nitride (TiN) and metal carbides such as chromium carbide (CrC), tungsten carbide (WC), and titanium carbide (TiC). Here, x and y can be any numbers between 0 and 1. Furthermore, in this invention, the numbers represented by x and y are values ​​used to represent the composition ratio between elements. Although x and y are stated to be values ​​between 0 and 1, they can also have values ​​(numerical values) greater than 1 in the actual molecular formula. In addition, in this invention, chromium oxide is represented as Cr. x O y Chromium nitride is represented as Cr x N y However, the x and y values ​​of chromium oxides can be different from those of chromium nitrides.

[0044] However, the hard layer in this invention is not limited to this; it can be formed from other materials as long as it can be used to improve the strength and wear resistance of the calender roll.

[0045] Furthermore, since the hard layer is used to increase the strength and wear resistance of the roll core, its thickness usually needs to be greater than that of the coating formed on the calender roll (approximately 1 μm). For example, the thickness of the hard layer can be formed to be more than approximately 20 μm.

[0046] Furthermore, the hard layer can be formed to a thickness of more than 20 μm by continuously depositing one layer (single layer), or it can be formed by depositing one layer discontinuously (at intervals), or by depositing two or more layers discontinuously.

[0047] Regarding implementation schemes for discontinuous deposition of more than two layers, in Figure 3 The explanation provides a more detailed description.

[0048] Next, a grinding step S120 can be performed on the hard layer formed in the hard layer forming step, so that the thickness of the hard layer at the center and the end of the calender roll is different.

[0049] In calendering rolls, when the thickness of the center and ends is the same, the force (linear pressure) that the calendered electrode exerts on the calendering roll is relatively large, which can cause the calendering roll to bend. Therefore, when pressure is applied to the electrode as the roll rotates, the pressure cannot be applied evenly, which may prevent the electrode sheet from being calendered smoothly.

[0050] Therefore, in the hard layer grinding step S120, by setting the thickness of the hard layer at the center and the ends of the calender roll to be different, bending of the calender roll is prevented, thereby allowing uniform pressure to be applied when applying pressure to the electrode. More specifically, by making the thickness at the center of the calender roll thicker than that at the ends (peripheral portions), uniform pressure can be applied when calendering the electrode sheet.

[0051] Next, a coating formation step S130 can be performed to form a coating on the hard layer that has been ground.

[0052] By forming the coating as described above, the hardness and wear resistance of the calender roll surface are improved, and the generation of step differences on the calender roll surface is prevented, thereby improving the calendering quality of the electrode sheet.

[0053] The method for manufacturing an electrode sheet calendering roll according to one embodiment of the present invention as described above can improve the strength and wear resistance of the calendering roll, and compared with the existing wet deposition method for forming Cr coating, it can play a significant role in suppressing environmental problems.

[0054] Relatedly, in the past, to improve the wear resistance of electrode rolling rolls, Cr was sometimes deposited using wet deposition. However, according to traditional wet deposition methods, due to the... 6+ This could lead to environmental problems.

[0055] In contrast, according to an embodiment of the present invention, Cr is not used. 6+ Instead, a hard layer is formed on the calender roll core by dry deposition of metals such as Cr or metal nitrides (or metal carbides) according to the PVD method, thereby preventing adverse environmental impacts.

[0056] Figure 2 This is a flowchart illustrating an embodiment of a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention.

[0057] Reference Figure 2 According to one embodiment of the present invention, the hard layer forming step may include: a plasma etching step S111 to remove impurities and / or oxide layers on the roller core; and a hard layer forming step S112 to deposit a hard layer of a specified thickness by sputtering or arc deposition.

[0058] The plasma etching step S111 is performed to remove impurities and / or oxide layers on the roller core, for example, by ion beam etching or ion gun etching at room temperature. This plasma etching improves the adhesion of the hard layer deposited on the roller core. When performing this ion beam etching or ion gun etching, Ar gas can be used, and the plasma formation voltage is typically above 1 kV, and the current is typically above 0.8 A.

[0059] Selected from chromium (Cr), tungsten (W), titanium (Ti), and chromium nitride (Cr) xN y (x and y are numbers between 0 and 1), chromium oxide (Cr x O y The hard layer formation step S112, in which a hard layer composed of materials such as chromium carbide (CrC), tungsten carbide (WC), titanium nitride (TiN), and titanium carbide (TiC) is deposited on the roll core, can be achieved by depositing a hard layer on the roll core using materials such as Cr, W, Ti, and Cr. x N y Cr x O y The process can be carried out by sputtering or arc deposition of CrC, WC, TiN or TiC, with HiPIMS being a specific sputtering method.

[0060] High-power pulsed magnetron sputtering (HiPIMS) is a vacuum deposition technique that uses high-power pulses to deposit thin films. It is a technique that can deposit high-quality films by applying high-power short electric pulses to significantly increase plasma density.

[0061] In addition, the electric arc deposition method is a technique that uses an electric arc to evaporate and deposit metal in a high vacuum environment. It can generate small plasma jets on the target surface to release the material for deposition.

[0062] The HiPIMS or arc deposition methods described above achieve a high ionization rate (over 50%) in the materials, which facilitates the deposition of high-quality, high-density films. Furthermore, to improve the ionization of Cr, W, Ti, and Cr content using the aforementioned HiPIMS or arc deposition methods... x N y Cr x O y The deposition rate of CrC, WC, TiN, or TiC can be achieved using one or more Cr, W, Ti, or Cr materials with a length longer than the effective working length of the calender roll. x N y Cr x O y Targets made of CrC, WC, TiN or TiC.

[0063] As described above, deposition by sputtering or arc deposition can be performed at temperatures above room temperature (15°C to 25°C) and below 200°C. To improve the properties of the deposited film (such as density), it is necessary to increase the temperature during deposition; however, excessively increasing the temperature may increase stress. Therefore, by performing sputtering or arc deposition at a chamber temperature above room temperature and below 200°C, a hard layer that does not produce layer peeling and minimizes internal stress can be formed.

[0064] Furthermore, argon (Ar) gas can be used in sputtering. For example, Ar gas at a flow rate of 150 standard cubic centimeters per minute (sccm) or higher can be introduced, and the current required to maintain the sputtered plasma can be 15A or higher.

[0065] Furthermore, the plasma etching step S111 and the hard layer formation step S112 performed by sputtering or arc deposition can be performed in the same chamber, and the hard layer formed by sputtering or arc deposition can be deposited to a thickness of approximately 20 μm or more.

[0066] Relatedly, coatings formed by PVD methods in industrial applications typically have a thickness of 5 μm or less, while the formation of films thicker than 20 μm is difficult due to peeling phenomena. In contrast, according to embodiments of the present invention, a metal layer (hard layer) with a thickness of 20 μm or more, and further 150 μm or more, can be formed without peeling phenomena by sputtering or arc deposition processes. Furthermore, when multiple hard layers are formed, the hard layers can be formed in such a way that the total thickness of the hard layers is 20 μm or more.

[0067] Furthermore, the hard layer formed by sputtering or arc deposition can be performed through a continuous process or through multiple steps. For example, when a continuous process is used to form a hard layer thickness of about 20 μm or more, the time required to form the hard layer can be shortened, thereby helping to improve productivity.

[0068] Furthermore, in the hard layer formation step S112 by sputtering or arc deposition, a single layer can be formed by a continuous process, or a hard layer can be formed by a discontinuous process at intervals. Forming a single layer by a discontinuous process has the advantage of reducing defect size.

[0069] Additionally, when forming multiple hard layers (two or more), deposition is performed using a discontinuous process. In this case, metal (chromium, tungsten, or titanium) layers and oxide (or nitride / carbide) layers can be formed alternately. See below for reference. Figure 3 The implementation scheme for forming multiple hard layers is described.

[0070] Figure 3 This is a flowchart illustrating, specifically, an embodiment of a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention, in the hard layer forming step, which includes a plurality of hard layers.

[0071] Reference Figure 3The hard layer deposition step S112 by sputtering or arc deposition may include: a first hard layer deposition step S112A, depositing a first hard layer composed of a material selected from chromium (Cr), tungsten (W), and titanium (Ti); and a second hard layer deposition step S112C, depositing a first hard layer composed of a material selected from chromium nitride (Cr). x N y ), chromium oxides (Cr x O y A second hard layer composed of materials such as chromium carbide (CrC), tungsten carbide (WC), titanium nitride (TiN), and titanium carbide (TiC) is deposited.

[0072] Furthermore, between the first hard layer deposition step S112A and the second hard layer deposition step S112C, a first hard layer etching step S112B can be performed to etch the first hard layer. The first hard layer etching step S112B can be performed by plasma etching.

[0073] As described above, by discontinuously depositing multiple layers, alternating between metal (e.g., chromium, tungsten, or titanium) layers and oxide (or nitride / carbide) layers, surface roughness can be ensured, and stress relief can also be achieved.

[0074] Furthermore, it is more advantageous to achieve stress relief when the first and second hard layers are of the same metal family. For example, when the first hard layer is a chromium (Cr) layer, the second hard layer is a chromium oxide (Cr) layer. x O y ) layer, chromium nitride (Cr x N y When a chromium carbide (CrC) layer or a chromium carbide (CrC) layer is applied, it can help relieve stress.

[0075] In addition, such as Figure 3 As shown, in addition to the discontinuous deposition of the first and second hard layers, a third hard layer deposition step S112E can be performed to further form a third hard layer on the second hard layer. The third hard layer can be, for example, composed of materials selected from chromium (Cr), tungsten (W), titanium (Ti), and chromium nitride (Cr). x N y ), chromium oxides (Cr x O y The material composition of chromium carbide (CrC), tungsten carbide (WC), titanium nitride (TiN) and titanium carbide (TiC).

[0076] Furthermore, between the second hard layer deposition step S112C and the third hard layer deposition step S112E, a second hard layer etching step S112D can be performed to etch the second hard layer. The second hard layer etching step S112D can be performed by plasma etching.

[0077] Furthermore, it is more advantageous to achieve stress relief when the first, second, and third hard layers are made of the same metal family. For example, when the first hard layer is a chromium (Cr) layer, the second hard layer is a chromium oxide (Cr) layer. x O y ) layer, chromium nitride (Cr x N y A third hard layer can be a chromium (Cr) layer or a chromium carbide (CrC) layer, and the third hard layer can be a chromium (Cr) layer, which can help relieve stress.

[0078] exist Figure 3 In the embodiments described, although a case of discontinuous deposition of three layers is illustrated, it is not limited to this; any layer consisting of two or more layers can be included within the scope of the invention. That is, the hard layer of the present invention can be formed by depositing only two layers, or it can be formed by depositing four or more layers. For example, the hard layer can be formed by sequentially depositing Cr layers, Cr... x O y Layer, Cr layer, Cr x O y Layers and Cr layers, thereby including the repeated formation of Cr layers and Cr x O y The invention comprises five layers. Furthermore, the thickness of each hard layer can be the same, but the invention is not limited to this; the thickness of each hard layer can also vary as needed.

[0079] Furthermore, when forming multiple hard layers, the outermost (topmost) hard layer can be composed of a material with a higher hardness than the hard layer formed before it (the hard layer directly below). Forming it in this way can improve the life of the calender roll.

[0080] For example, when the hard layer consists only of a first hard layer and a second hard layer, and the first hard layer is a chromium (Cr) layer, the second hard layer can be a chromium oxide (Cr) with a hardness higher than Cr. x O y )layer.

[0081] However, when the deposition rate of the required hard layer is more important, the outermost hard layer can also be formed of a material with a lower hardness than the hard layers formed before it. For example, when the first hard layer is a Cr layer and the second hard layer is Cr... x O y When the layers are layered, the third hard layer can be a Cr layer.

[0082] Specifically, the deposition rate of the metal layer is higher than that of the metal oxide (or nitride / carbide). Therefore, when improving the yield is more important, the deposition rate of the overall hard layer can be accelerated by making the first and third hard layers, which serve as the metal layer, thicker than the second hard layer.

[0083] As described above, in the hard layer formation step, when forming multiple (two or more) hard layers through discontinuous deposition, the deposition can be carried out in multiple steps with a specified thickness. In this case, the total thickness of the hard layer can be approximately 20 μm or more.

[0084] Figure 4 This is a flowchart illustrating a specific embodiment of a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention, specifically showing a hard layer grinding step in one of the embodiments of the present invention.

[0085] Reference Figure 4 According to one embodiment of the present invention, the hard layer grinding step S120 may include: a primary grinding step S121 for adjusting the thickness of the hard layer; and a mirror grinding step S122 for performing mirror grinding so that the surface roughness is lower than a specified value.

[0086] In one grinding step S121, a thickness adjustment operation can be performed to make the thickness of the hard layer in the center and the ends of the calender roll different. More specifically, grinding can be performed so that the thickness in the center of the calender roll is thicker than that in the ends (peripheral parts).

[0087] For example, when the thickness of the hard layer in the center of the calender roll is set to 20 μm, the ends can be ground to make the thickness 10 μm.

[0088] In addition, in order to apply uniform pressure to the electrode sheet, the thickness difference between the center and the end of the calender roll is preferably 10 μm to 15 μm.

[0089] The reason for forming a hard layer on the roll core is to improve the strength of the roll core; therefore, the minimum thickness of the hard layer needs to be 10 μm or more. Thus, the deposition thickness of the hard layer formed on the roll core (thickness deposited via PVD) needs to be 20 μm or more, so that the thickness of the hard layer at the end of the polished roll can be 10 μm or more, and the difference between the center and the end can be approximately 10 μm to 15 μm.

[0090] In addition, after the first grinding to adjust the thickness of the hard layer, mirror grinding S122 can be performed to make the surface of the hard layer smooth.

[0091] In the mirror polishing step S122, polishing can be performed to smooth the surface until the surface roughness of the hard layer is lower than a specified value. For example, mirror polishing can be performed until the surface roughness (Ra) of the hard layer is lower than 0.02.

[0092] Furthermore, according to existing wet plating methods, the coating inevitably contains hydrogen (H) after wet plating. Therefore, after one grinding, a heat treatment (dehydrogenation treatment) is required to remove hydrogen (H) and metal hydroxides (e.g., hydrogen chromate (H2CrO4 or H2Cr2O7)).

[0093] However, according to the embodiment of the present invention utilizing dry deposition (PVD), the dehydrogenation heat treatment for removing hydrogen (H) and the like from the interior of the hard layer can be omitted, and grinding and mirror polishing can be performed continuously in one step. Therefore, it can improve work efficiency and shorten work time.

[0094] Figure 5 This is a flowchart illustrating a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) according to another embodiment of the present invention.

[0095] Reference Figure 5 According to another embodiment of the present invention, a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) is described. Figure 1 After the hard layer grinding step S120, a coating forming step S130 may be further included to form a coating on the hard layer.

[0096] Figure 6 This is a flowchart illustrating an embodiment of a method for manufacturing an electrode sheet calendering roll comprising a hard layer formed by physical vapor deposition (PVD) according to another embodiment of the invention.

[0097] The coating formation step S130 may include a plasma etching step S131 for removing impurities and / or oxide layers on the hard layer. This plasma etching can improve the adhesion of the coating when forming on a mirror-polished hard layer, for example, by ion beam etching.

[0098] After the plasma etching step S131, a buffer layer formation step S132 can be performed to form at least one buffer layer on the hard layer, followed by a DLC layer formation step S133 to form a diamond-like carbon (DLC) layer on the buffer layer by ion beam deposition or chemical vapor deposition (CVD).

[0099] DLC layer can be a coating that imparts high surface hardness, wear resistance and lubricity to the surface of calender rolls. Diamond-like carbon (DLC) has an intermediate structure that is a mixture of diamond and graphite, and has high hardness similar to diamond as well as excellent wear resistance, solid lubricity, thermal conductivity, chemical stability and corrosion resistance.

[0100] Additionally, before forming the DLC layer, the adhesion of the DLC layer can be improved and the DLC layer can be prevented from peeling off from the hard layer by forming at least one (e.g., two) buffer layers.

[0101] At least one buffer layer may include, for example, a first buffer layer and a second buffer layer, wherein the first buffer layer can prevent oxidation of the calender roll surface and ensure primary surface strength to withstand calendering loads transmitted through the outer DLC layer, and the second buffer layer can be formed to facilitate adhesion during the formation of the DLC layer (to ensure the adhesion of the coating).

[0102] The first and second buffer layers can be formed using various thin film formation methods, such as sputtering, vacuum deposition, ion plating, molecular beam epitaxy, laser ablation, and ion-assisted methods.

[0103] For example, the first buffer layer can be formed by sputtering any one of chromium (Cr), tungsten (W), titanium (Ti), and zirconium (Zr) to form a coating of the metal, and can form a thickness in the range of 0.1 μm to 2 μm.

[0104] Furthermore, the second buffer layer can be coated with a nitride or carbide of the same metal as the first buffer layer (for example, when the first buffer layer is Cr, Cr...). x N y Cr x C y Cr x C y N z (x, y, and z are numbers between 0 and 1), by having lattice constants and coefficients of thermal expansion corresponding to those between the first buffer layer and the DLC layer, particles can adhere smoothly during coating, the coatings exhibit excellent adhesion, and internal stress variations with temperature can be reduced, thereby helping to prevent interlayer delamination. The thickness of the second buffer layer can be formed in the range of 0.1 μm to 1 μm.

[0105] The DLC layer can be formed on the buffer layer using ion beam deposition or chemical vapor deposition (CVD) methods. For example, the DLC layer can be coated using an ion beam (ion gun) source. The coating voltage can be from 500V to 3000V, the current can be from 0.2A to 3A, and the gas used as the deposition source can be hydrocarbon (C). X H Y) series gases, such as CH4, C2H2, C6H6, C4H 10 In the formation of the DLC layer, F can be added to adjust the contact angle, or Si can be added to adjust the coefficient of friction, thereby forming the DLC layer.

[0106] For example, the thickness of the DLC layer can be formed to be from 0.1 μm to 3 μm. This is because when the thickness of the DLC layer is less than 0.1 μm, the wear resistance and durability of the calender roll are significantly reduced, and when the thickness of the DLC layer exceeds 3 μm, the internal stress of the coating itself becomes too high, making it prone to peeling.

[0107] Figure 7 This is a side cross-sectional view of an electrode sheet calendering roll including a hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention.

[0108] Reference Figure 7 A hard layer 20 is formed on the cylindrical roll core 10. The thickness of the hard layer 20 at the center of the calender roll and the thickness at the end of the calender roll can be different.

[0109] For example, such as Figure 7 As shown, the hard layer 20 according to one embodiment of the present invention may include: a first region 21 having a constant thickness region of length a on the center side; and a second region 22 having a length b and a thickness that gradually thins towards the end side, wherein the thickness T1 of the center of the calender roll may have a thickness of 20 μm or more, and the thickness T2 of the end of the calender roll may have a thickness of 10 μm or more.

[0110] exist Figure 7 In the embodiments described, although an embodiment including a first region 21 having the same thickness as the center and a second region 22 whose thickness gradually decreases towards the end is illustrated, it is not limited to this. For example, it may also be formed in a form where the thickness continuously decreases from the center to the end.

[0111] Figure 8 (a) is a cross-sectional view of the center portion of an electrode sheet calendering roll comprising a single hard layer formed by physical vapor deposition (PVD) according to an embodiment of the present invention. Figure 8 (b) is a cross-sectional view of the end of an electrode sheet calendering roll comprising a single hard layer according to an embodiment of the present invention.

[0112] like Figure 8 As shown in (a) and (b), the calendering roll 100 according to an embodiment of the present invention may include: a roll core 10 composed of carbon-containing steel; and a hard layer 20 formed on the roll core 10 by a PVD method, specifically by a sputtering or arc deposition method.

[0113] The method for forming a hard layer 20 on the roller core 10 has been described in detail above, so the detailed description is omitted here.

[0114] like Figure 8 As can be confirmed by (a) and (b), after PVD deposition, the thickness of the hard layer 20 at the center and ends of the calender roll can be formed differently by a grinding process. Specifically, in the hard layer 20 according to an embodiment of the present invention, the thickness of the hard layer at the ends of the calender roll can be formed to be thinner than the thickness of the hard layer at the center of the calender roll.

[0115] Specifically, in Figure 8 In (a), the thickness of the hard layer 20 in the center of the calender roll can be 20 μm or more. Figure 8 In (b), the thickness of the hard layer 20 at the end of the calender roll can be 10 μm or more. In addition, in order to improve calendering performance, the difference between the thickness of the hard layer 20 at the center of the calender roll and the thickness of the hard layer 20 at the end of the calender roll is preferably about 10 μm to 15 μm.

[0116] Figure 9 (a) is a cross-sectional view of the center portion of an electrode sheet calendering roll comprising multiple hard layers formed by physical vapor deposition (PVD) according to an embodiment of the present invention. Figure 9 (b) is a cross-sectional view of the end of an electrode sheet calendering roll comprising a plurality of hard layers according to an embodiment of the present invention.

[0117] like Figure 9 As shown in (a) and (b), in embodiments including multiple hard layers, hard layer 20 may include a first hard layer 20A, a second hard layer 20B, and a third hard layer 20C. Each hard layer may be formed by a PVD method, specifically by sputtering or arc deposition.

[0118] exist Figure 9 In (a), the thickness of the hard layer 20 at the center of the calender roll (the sum of the thicknesses of the first hard layer to the third hard layer) can be 20 μm or more. Figure 9 In (b), the thickness of the hard layer 20 at the end of the calender roll (the sum of the thicknesses of the first hard layer to the third hard layer) can be 10 μm or more. Furthermore, the thicknesses of the first hard layer 20A, the second hard layer 20B, and the third hard layer 20C can be the same, but the present invention is not limited to this; the thicknesses of each hard layer can also be different as needed.

[0119] In addition, in order to improve the calendering performance, the difference between the thickness of the hard layer 20 at the center of the calender roll and the thickness of the hard layer 20 at the end of the calender roll is preferably about 10 μm to 15 μm.

[0120] Figure 10 (a) is a cross-sectional view of the central portion of an electrode sheet calendering roll comprising a single hard layer and a coating formed by physical vapor deposition (PVD) according to another embodiment of the invention. Figure 10 (b) is a cross-sectional view of the end of an electrode sheet calendering roll comprising a single hard layer and a coating according to another embodiment of the invention.

[0121] like Figure 10 As shown in (a) and (b), a calendering roll 100 according to another embodiment of the invention may include a roll core 10 made of carbon-containing steel, a hard layer 20 formed on the roll core 10 by a PVD method, and coatings (30, 40) formed on the hard layer 20.

[0122] The coating may include, for example, a first buffer layer 31, a second buffer layer 32, and a DLC layer 40. The methods for forming the hard layer 20 on the roller core 10, and the methods for forming the first buffer layer 31, the second buffer layer 32, and the DLC layer 40 on the hard layer 20, have been described in detail above, and therefore, detailed descriptions are omitted here.

[0123] from Figure 10 As can be confirmed by (a) and (b), after PVD deposition, the thickness of the hard layer 20 at the center and ends of the calender roll can be formed differently by a grinding process. Specifically, according to an embodiment of the invention, the thickness of the hard layer 20 at the ends of the calender roll can be formed to be thinner than the thickness of the hard layer at the center of the calender roll.

[0124] Specifically, in the center of the calender roll, in Figure 10 In (a), the thickness of the hard layer 20 in the center of the calender roll can be 20 μm or more. Figure 10 In (b), the thickness of the hard layer 20 at the end of the calender roll can be 10 μm or more. In addition, in order to improve calendering performance, the difference between the thickness of the hard layer 20 at the center of the calender roll and the thickness of the hard layer 20 at the end of the calender roll is preferably about 10 μm to 15 μm.

[0125] Furthermore, the thickness of the first buffer layer 31 can be approximately 0.1 μm to 2 μm, the thickness of the second buffer layer 32 can be approximately 0.1 μm to 1 μm, and the thickness of the DLC layer 40 can be approximately 0.1 μm to 3 μm. For example... Figure 10 As can be confirmed in (a) and (b), the first buffer layer 31, the second buffer layer 32 and the DLC layer 40 can be formed to the same thickness at the center and the end of the calender roll.

[0126] Furthermore, although the above embodiments illustrate the formation of a first buffer layer 31 and a second buffer layer 32, it is also possible to form only one buffer layer and form a DLC layer 40 on top of it. Moreover, in embodiments of the present invention, the coating formation can have various implementations, but is not limited to this.

[0127] According to the embodiments of the present invention as described above, when manufacturing electrode sheet calendering rolls, a hard layer is formed by PVD, which is an environmentally friendly method, thereby solving environmental problems and providing an electrode sheet calendering roll and its manufacturing method that can promote improved wear resistance and extended life of the calendering roll, thereby achieving significant effects that cannot be predicted from the prior art.

[0128] Furthermore, the electrode sheet calendering roll and its manufacturing method according to embodiments of the present invention, which includes a hard layer formed by physical vapor deposition (PVD), can omit the dehydrogenation treatment that is unavoidable during wet plating, and can continuously perform grinding operations on the hard layer, thereby improving productivity. In addition, it can also exert a significant effect of fundamentally preventing adverse effects that may occur after dehydrogenation treatment.

[0129] The above description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific embodiments can be readily modified without changing the technical concept or essential features of the invention. Therefore, it should be understood that the above embodiments are exemplary in all respects and not limiting. For example, the constituent elements described in a single form may also be implemented separately, and similarly, the constituent elements described in a separate form may also be implemented in combination.

[0130] The scope of this invention should be determined by the claims, not by the detailed description above, and should be interpreted as including all modifications or variations derived from the meaning, scope, and equivalents of the claims.

Claims

1. A method for manufacturing an electrode sheet calendering roll, characterized in that, The electrode calendering roll includes a hard layer formed by physical vapor deposition (PVD), and the manufacturing method of the electrode calendering roll includes: The hard layer forming step involves forming a hard layer on a roll core composed of carbon-containing steel using a PVD method; and The hard layer grinding step grinds the hard layer so that the thickness of the hard layer is different at the center and the ends of the calender roll.

2. The method for manufacturing an electrode sheet calendering roll according to claim 1, characterized in that, The hard layer formation step includes: The first hard layer deposition step involves depositing a first hard layer composed of a material selected from Cr, W, and Ti; and The second hard layer deposition step will be performed using materials selected from Cr. x N y Cr x O y A second hard layer composed of materials from CrC, WC, TiN, and TiC is deposited, wherein the Cr x N y In the Cr, x and y are numbers between 0 and 1. x O y x and y are numbers between 0 and 1.

3. The method for manufacturing an electrode sheet calendering roll according to claim 2, characterized in that, In the hard layer formation step, after the first hard layer deposition step and the second hard layer deposition step, a third hard layer deposition step is further included, which deposits a third hard layer on the second hard layer. The third hard layer is composed of materials selected from Cr, W, Ti, and Cr. x N y Cr x O y The material composition is composed of CrC, WC, TiN and TiC, wherein the Cr x N y In the Cr, x and y are numbers between 0 and 1. x O y x and y are numbers between 0 and 1.

4. The method for manufacturing an electrode sheet calendering roll according to any one of claims 1 to 3, characterized in that, The hard layer formation step involves using sputtering or arc deposition methods in the PVD process to deposit Cr, W, Ti, and Cr. x N y Cr x O y CrC, WC, TiN, or TiC are deposited on the roller core, wherein the Cr x N y In the Cr, x and y are numbers between 0 and 1. x O y x and y are numbers between 0 and 1.

5. The method for manufacturing an electrode sheet calendering roll according to any one of claims 1 to 3, characterized in that, The hard layer polishing step includes the following steps: A grinding process is performed such that the thickness of the hard layer at the end of the calender roll is thinner than the thickness of the hard layer at the center of the calender roll; and Mirror polishing is performed to make the surface roughness of the hard layer lower than a specified value.

6. The method for manufacturing an electrode sheet calendering roll according to any one of claims 1 to 3, characterized in that, Following the hard layer grinding step, a coating forming step is further included to form a coating on the hard layer.

7. The method for manufacturing an electrode sheet calendering roll according to claim 6, characterized in that, The coating formation step further includes: The buffer layer forming step involves forming at least one buffer layer by coating a metallic material; and The diamond-like carbon (DLC) layer formation steps are performed by ion beam deposition or chemical vapor deposition (CVD) methods to form the DLC layer.

8. An electrode sheet calendering roll, characterized in that, The electrode calendering roll includes a hard layer formed by physical vapor deposition (PVD), and the electrode calendering roll includes: A roller core made of carbon-containing steel; and A hard layer formed on the roller core using a PVD method. In the hard layer, the center and ends of the calender roll are formed to have different thicknesses through grinding.

9. The electrode sheet calendering roll according to claim 8, characterized in that, The thickness of the hard layer is such that the thickness of the hard layer at the end of the calender roll is thinner than the thickness of the hard layer at the center of the calender roll.

10. The electrode sheet calendering roll according to claim 8 or 9, characterized in that, The hard layer includes: A first hard layer, the first hard layer being composed of a material selected from Cr, W and Ti; and The second hard layer, the second hard layer is composed of materials selected from Cr x N y Cr x O y The material composition is composed of CrC, WC, TiN and TiC, wherein the Cr x N y In the Cr, x and y are numbers between 0 and 1. x O y x and y are numbers between 0 and 1.

Images