Electrode sheet hot rolling apparatus and electrode sheet hot rolling method

Abstract

An electrode sheet hot rolling apparatus (10) according to the present invention includes: a rolling roller (100) for rolling an electrode sheet (50); and a first heating unit (120) for heating the rolling roller (100) and increasing the temperature of the surface of the rolling roller (100) in contact with the electrode sheet (50) to a first temperature (T1). The rolling roller (100) is a crown roller, and accordingly, the radius of a first cross section of a central portion of the rolling roller (100) in the axial direction may be larger than the radius of a second cross section of one end and the radius of a third cross section of the other end of the rolling roller (100) in the axial direction, the rolling roller (100) may have a first length (L) in the axial direction, and the first cross section may have a first diameter (D). A crown value (N) of the rolling roller (100) may be equal to or greater than a first reference value and equal to or less than a second reference value greater than the first reference value, the crown value (N) being the radius of the second cross section or the third cross section subtracted from the radius of the first cross section. The first reference value is greater than 0, and the second reference value can be calculated by the following equation 1. [Equation 1] (Here, C1 is 0.0155 mm, L is the first length, and D is the first diameter)

Description

Electrode sheet hot rolling device and electrode sheet hot rolling method

[0001] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0012511, dated January 26, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an electrode sheet hot rolling device and an electrode sheet hot rolling method, and more particularly, to an electrode sheet hot rolling device and an electrode sheet hot rolling method, which enable the electrode sheet to be rolled at a high density while maintaining a constant thickness in the width direction of the electrode sheet, thereby improving the capacity and quality of electrodes and secondary batteries, and providing an appropriate range, an optimal range, and an optimal value of the crown value of a rolling roller used in hot rolling.

[0003] As technological development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing. Recently, the use of secondary batteries as a power source for electric vehicles (EVs) and hybrid electric vehicles (HEVs) has become a reality, and among such secondary batteries, the demand for lithium secondary batteries with high energy density, high discharge voltage, and output stability is high.

[0004] To increase the energy density of lithium secondary batteries, it is essential to manufacture electrodes (positive or negative electrodes) with a high rolling density. Lithium secondary battery electrodes can be manufactured by rolling and forming electrode sheets coated with a composite layer containing electrode active materials using a rolling machine.

[0005] Traditionally, electrode sheets were primarily cold rolled. Rolling rollers used in cold rolling have a crowned, convex central axial shape. This is to ensure that the upper and lower surfaces of the electrode sheet are rolled flat, taking into account the rolling force generated during rolling.

[0006] However, the recent trend is to use hot rolling, a high-density rolling technology, to produce high-capacity, high-efficiency electrodes. If the rolling rollers used in hot rolling have crowns, the crown value of the rolling rollers used in cold rolling cannot be directly applied. This is because the rolling strength of the rolling rollers differs when the electrode sheet is hot rolled and cold rolled, and the degree of bending / deformation of the rolling rollers differs, resulting in a different appropriate crown value for the rolling rollers. Therefore, it is necessary to provide an appropriate crown value for the rolling rollers used in the hot rolling of electrode sheets.

[0007] Prior art related to this is Korean Patent Publication No. 10-2017-0037100.

[0008] The present invention has been devised to solve the above-described problems, and its purpose is to provide an electrode sheet hot rolling device and an electrode sheet hot rolling method in which an electrode sheet is rolled at a high density while the electrode sheet is rolled at a constant thickness in the width direction of the electrode sheet.

[0009] The purpose of the present invention is to provide an electrode sheet hot rolling device and an electrode sheet hot rolling method that improve the capacity and quality of electrodes and secondary batteries.

[0010] The purpose of the present invention is to provide an electrode sheet hot rolling device and an electrode sheet hot rolling method that provide an appropriate range, an optimal range, and an optimal value of the crown value of a rolling roller used in hot rolling an electrode sheet.

[0011] The purpose of the present invention is to provide an electrode sheet hot rolling device and an electrode sheet hot rolling method in which a rolling roller has a more appropriate crown value.

[0012] The purpose of the present invention is to provide an electrode sheet hot rolling device and an electrode sheet hot rolling method that improve the rolling uniformity of the electrode sheet.

[0013]

[0014] The technical objectives of the present invention are not limited to the purposes mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0015] To solve the above-described problem, the present invention provides an electrode sheet hot rolling device (10) including a rolling roller (100); and a first heating unit (120).

[0016] The above rolling roller (100) can roll the electrode sheet (50).

[0017] The above rolling roller (100) may be a crown roller.

[0018] Accordingly, the radius of the first cross-section of the axial central portion of the rolling roller (100) may be greater than the radius of the second cross-section of one axial end of the rolling roller (100) and the radius of the third cross-section of the other axial end.

[0019] The above rolling roller (100) may have a first length (L) in the axial direction.

[0020] The first cross-section of the above rolling roller (100) may have a first diameter (D).

[0021] The crown value (N) of the rolling roller (100), which is a value obtained by subtracting the radius of the second or third cross-section from the radius of the first cross-section, may be equal to or greater than a first reference value and equal to or less than a second reference value that is greater than the first reference value.

[0022] The above first reference value may be greater than 0.

[0023] The above second reference value may have a value calculated by the following mathematical formula 1.

[0024] [Mathematical Formula 1]

[0025]

[0026] Here, C1 may be 0.0155 mm, L may be the first length, and D may be the first diameter.

[0027] The above first heating unit (120) can heat the rolling roller (100).

[0028] The above first heating unit (120) can raise the temperature of the surface of the rolling roller (100) in contact with the electrode sheet (50) to the first temperature (T1).

[0029] In one embodiment, the crown value (N) may be greater than or equal to a third reference value that is greater than the first reference value, and less than or equal to a fourth reference value that is greater than the third reference value and less than the second reference value.

[0030] The third and fourth reference values ​​may have values ​​calculated by the following mathematical expressions 2 and 3, respectively.

[0031] [Equation 2]

[0032]

[0033] Here, C2 may be 0.0046 mm, L may be the first length, and D may be the first diameter.

[0034] [Equation 3]

[0035]

[0036] Here, C3 may be 0.007 mm, L may be the first length, and D may be the first diameter.

[0037] In one embodiment, the crown value (N) may be an optimal value that is greater than or equal to the third reference value and less than or equal to the fourth reference value.

[0038] The above optimal value can have a value calculated by the following mathematical formula 4.

[0039] [Equation 4]

[0040]

[0041] Here, C4 may be 0.0058 mm, L may be the first length, and D may be the first diameter.

[0042] In one embodiment, the rolling roller (100) may be coupled to a rotational axis (A).

[0043] The above rolling roller (100) can be supported at two axial points (P1, P2) by the rotation axis (A) during rolling.

[0044] The above rolling roller (100) may have shapes of one side and the other side symmetrical with respect to the midpoint of the two points (P1, P2) in the axial direction.

[0045] In one embodiment, the first cross-section may be a cross-section perpendicular to the axial direction at the midpoint.

[0046] In one embodiment, the rolling roller (100) may be coupled to a rotational axis (A).

[0047] The above rolling roller (100) can be supported at two axial points (P1, P2) by the rotation axis (A) during rolling.

[0048] The second and third cross sections may be cross sections perpendicular to the axial direction at the two points (P1, P2), respectively.

[0049] In one embodiment, the rolling roller (100) may be coupled to a rotational axis (A).

[0050] The above rolling roller (100) can be supported at two axial points (P1, P2) by the rotation axis (A) during rolling.

[0051] The above first length (L) may correspond to the axial distance between the two points (P1, P2).

[0052] To solve the above-described problem, the present invention provides an electrode sheet hot rolling device (10) including a rolling roller (100); and a first heating unit (120).

[0053] The above rolling roller (100) can roll the electrode sheet (50).

[0054] The above rolling roller (100) may be a crown roller.

[0055] Accordingly, the radius of the first cross-section of the axial central portion of the rolling roller (100) may be greater than the radius of the second cross-section of one axial end of the rolling roller (100) and the radius of the third cross-section of the other axial end.

[0056] The crown value (N) of the rolling roller (100), which is a value obtained by subtracting the radius of the second or third cross-section from the radius of the first cross-section, may be equal to or greater than a first reference value and equal to or less than a second reference value that is greater than the first reference value.

[0057] The above first reference value may be greater than 0.

[0058] The above second reference value may be 20um.

[0059] The above first heating unit (120) can heat the rolling roller (100).

[0060] The above first heating unit (120) can raise the temperature of the surface of the rolling roller (100) in contact with the electrode sheet (50) to the first temperature (T1).

[0061] In one embodiment, the crown value (N) may be greater than or equal to a third reference value that is greater than the first reference value, and less than or equal to a fourth reference value that is greater than the third reference value and less than the second reference value.

[0062] The third and fourth reference values ​​may be 6 um and 9 um, respectively.

[0063] In one embodiment, the crown value (N) may be an optimal value that is greater than or equal to the third reference value and less than or equal to the fourth reference value.

[0064] The above optimal value may be 7.5um.

[0065] In one embodiment, the electrode sheet hot rolling device (10) may include a preheater (200); and a second heating unit (220).

[0066] The above preheater (200) can be in contact with the above electrode sheet (50).

[0067] The above preheater (200) can preheat the electrode sheet (50).

[0068] The above second heating unit (220) can heat the above preheater (200).

[0069] The above second heating unit (220) can increase the temperature of the surface of the preheater (200) in contact with the electrode sheet (50) to the second temperature (T2).

[0070] The above rolling roller (100) can roll the electrode sheet (50) preheated by the above preheater (200).

[0071] In one embodiment, the first temperature (T1) may be higher than or equal to the second temperature (T2).

[0072] In one embodiment, the preheater (200) may be a preheating roller.

[0073] In one embodiment, the first reference value may be 0.001 mm.

[0074] In order to solve the above-described problem, the present invention provides an electrode sheet hot rolling method (S500) including a rolling process (S510) of rolling the electrode sheet (50) with the rolling roller (100) having the crown value (N) equal to or greater than the first reference value and equal to or less than the second reference value while the temperature of the surface of the rolling roller (100) is increased to the first temperature (T1) by the first heating unit (120).

[0075] In one embodiment, in the rolling process (S510), the electrode sheet (50) may be preheated by contacting the preheater (200) whose surface temperature is raised to a second temperature (T2) by the second heating unit (220), and then the electrode sheet (50) may be rolled by the rolling roller (100).

[0076] According to embodiments of the present invention, an electrode sheet hot rolling device (10) may include a rolling roller (100) for rolling an electrode sheet (50); and a first heating unit (120) for heating the rolling roller (100) and increasing the temperature of a surface of the rolling roller (100) in contact with the electrode sheet (50) to a first temperature (T1). The rolling roller (100) is a crown roller, and thus, a radius of a first cross-section of an axially central portion of the rolling roller (100) is larger than a radius of a second cross-section of an axially one end of the rolling roller (100) and a radius of a third cross-section of an axially opposite end of the rolling roller (100), and has a first length (L) in the axial direction, and the first cross-section may have a first diameter (D). The crown value (N) of the rolling roller (100), which is a value obtained by subtracting the radius of the second or third cross-section from the radius of the first cross-section, may be equal to or greater than a first reference value and equal to or less than a second reference value that is greater than the first reference value. The first reference value may be greater than 0. The second reference value may have a value calculated by the following mathematical expression 1.

[0077] [Mathematical Formula 1]

[0078]

[0079] Here, C1 may be 0.0155 mm, L may be the first length, and D may be the first diameter.

[0080] Accordingly, since the electrode sheet (50) is hot rolled with a crown-endowed rolling roller (100), the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50). Accordingly, the capacity and quality of the electrode and secondary battery can be improved.

[0081] In addition, it is possible to provide an appropriate range of the crown value (N) of the rolling roller (100) used for hot rolling of the electrode sheet (50). That is, since the crown value (N) of the rolling roller (100) used for hot rolling is equal to or greater than the first reference value and equal to or less than the second reference value, the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50).

[0082] According to embodiments of the present invention, the crown value (N) may be equal to or greater than a third reference value that is greater than the first reference value, and equal to or less than a fourth reference value that is greater than the third reference value and less than the second reference value. The third reference value and the fourth reference value may have values ​​calculated by the following mathematical expressions 2 and 3, respectively.

[0083] [Equation 2]

[0084]

[0085] Here, C2 may be 0.0046 mm, L may be the first length, and D may be the first diameter.

[0086] [Equation 3]

[0087]

[0088] Here, C3 may be 0.007 mm, L may be the first length, and D may be the first diameter.

[0089] Accordingly, the optimal range of the crown value (N) of the rolling roller (100) used for hot rolling of the electrode sheet (50) can be provided. That is, since the crown value (N) of the rolling roller (100) used for hot rolling is equal to or greater than the third reference value and equal to or less than the fourth reference value, the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made more consistent in the width direction of the electrode sheet (50).

[0090] According to embodiments of the present invention, the crown value (N) may be an optimal value that is greater than or equal to the third reference value and less than or equal to the fourth reference value. The optimal value may have a value calculated by the following mathematical expression 4.

[0091] [Equation 4]

[0092]

[0093] Here, C4 may be 0.0058 mm, L may be the first length, and D may be the first diameter.

[0094] Accordingly, the optimal value of the crown value (N) of the rolling roller (100) used for hot rolling of the electrode sheet (50) can be provided. That is, since the crown value (N) of the rolling roller (100) used for hot rolling is the optimal value, the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made more consistent in the width direction of the electrode sheet (50).

[0095] According to embodiments of the present invention, the rolling roller (100) is coupled to a rotational axis (A), and two points (P1, P2) in the axial direction are supported by the rotational axis (A) during rolling, and the shapes of one side and the other side may be symmetrical with respect to the midpoint of the two points (P1, P2) in the axial direction.

[0096] Accordingly, the second reference value, the third reference value, the fourth reference value, and / or the optimal value calculated by mathematical expressions 1, 2, 3, and / or 4 can be made accurate. Accordingly, the rolling roller (100) can have a more appropriate crown value (N).

[0097] According to embodiments of the present invention, the first cross-section may be a cross-section perpendicular to the axial direction at the midpoint.

[0098] Accordingly, the second reference value, the third reference value, the fourth reference value, and / or the optimal value calculated by mathematical expressions 1, 2, 3, and / or 4 can be made accurate. Accordingly, the rolling roller (100) can have a more appropriate crown value (N).

[0099] According to embodiments of the present invention, the rolling roller (100) is coupled to a rotational axis (A), and two axial points (P1, P2) can be supported by the rotational axis (A) during rolling. The second cross-section and the third cross-section may be cross-sections perpendicular to the axial direction at the two points (P1, P2), respectively.

[0100] Accordingly, the second reference value, the third reference value, the fourth reference value, and / or the optimal value calculated by mathematical expressions 1, 2, 3, and / or 4 can be made accurate. Accordingly, the rolling roller (100) can have a more appropriate crown value (N).

[0101] According to embodiments of the present invention, the rolling roller (100) is coupled to a rotational axis (A), and two axial points (P1, P2) can be supported by the rotational axis (A) during rolling. The first length (L) may correspond to an axial distance between the two points (P1, P2).

[0102] Accordingly, the second reference value, the third reference value, the fourth reference value, and / or the optimal value calculated by mathematical expressions 1, 2, 3, and / or 4 can be made accurate. Accordingly, the rolling roller (100) can have a more appropriate crown value (N).

[0103] According to embodiments of the present invention, an electrode sheet hot rolling device (10) may include a rolling roller (100) for rolling an electrode sheet (50); and a first heating unit (120) for heating the rolling roller (100) and increasing the temperature of a surface of the rolling roller (100) in contact with the electrode sheet (50) to a first temperature (T1). The rolling roller (100) is a crown roller, and thus, a radius of a first end surface of an axial central portion of the rolling roller (100) may be larger than a radius of a second end surface of an axial one end surface of the rolling roller (100) and a radius of a third end surface of an axial other end surface. A crown value (N) of the rolling roller (100), which is a value obtained by subtracting the radius of the second end surface or the third end surface from the radius of the first end surface, may be equal to or greater than a first reference value and equal to or less than a second reference value that is larger than the first reference value. The above first reference value may be greater than 0. The above second reference value may be 20um.

[0104] Accordingly, the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50).

[0105] According to embodiments of the present invention, the crown value (N) may be equal to or greater than a third reference value that is greater than the first reference value, and equal to or less than a fourth reference value that is greater than the third reference value and less than the second reference value. The third and fourth reference values ​​may be 6 um and 9 um, respectively.

[0106] Accordingly, while the electrode sheet (50) is rolled at a high density, the thickness of the electrode sheet (50) can be made more consistent in the width direction of the electrode sheet (50).

[0107] According to embodiments of the present invention, the crown value (N) may be an optimal value that is greater than or equal to the third reference value and less than or equal to the fourth reference value. The optimal value may be 7.5 um.

[0108] Accordingly, while the electrode sheet (50) is rolled at a high density, the thickness of the electrode sheet (50) can be made more consistent in the width direction of the electrode sheet (50).

[0109] According to embodiments of the present invention, the device may include a preheater (200) that comes into contact with the electrode sheet (50) and preheats the electrode sheet (50); and a second heating unit (220) that heats the preheater (200) and raises the temperature of the surface of the preheater (200) that comes into contact with the electrode sheet (50) to a second temperature (T2). The rolling roller (100) may roll the electrode sheet (50) preheated by the preheater (200).

[0110] Accordingly, since the electrode sheet (50) is preheated before being rolled on the rolling roller (100), the temperature of the surface of the rolling roller (100) can be easily and stably maintained at the first temperature (T1). Accordingly, the rolling uniformity of the electrode sheet (50) can be improved, and thus the quality of the electrode and secondary battery can be improved.

[0111] According to embodiments of the present invention, the first temperature (T1) may be higher than or equal to the second temperature (T2).

[0112] Accordingly, since the temperature of the surface of the rolling roller (100) is higher than or equal to the temperature of the surface of the preheater (200), the temperature of the surface of the rolling roller (100) can be easily and stably maintained at the first temperature (T1). Accordingly, the rolling uniformity of the electrode sheet (50) can be improved, and thus the quality of the electrode and secondary battery can be improved.

[0113] According to embodiments of the present invention, the preheater (200) may be a preheating roller.

[0114] Accordingly, the electrode sheet (50) can be effectively preheated.

[0115] According to embodiments of the present invention, the first reference value may be 0.001 mm.

[0116] Accordingly, since the electrode sheet (50) is hot rolled with a crown-endowed rolling roller (100), the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50).

[0117] According to embodiments of the present invention, the electrode sheet hot rolling method (S500) may include a rolling process (S510) of rolling the electrode sheet (50) with the rolling roller (100) having the crown value (N) equal to or greater than the first reference value and equal to or less than the second reference value, while the temperature of the surface of the rolling roller (100) is increased to the first temperature (T1) by the first heating unit (120).

[0118] Accordingly, since the electrode sheet (50) is hot rolled with a crown-endowed rolling roller (100), the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50). Accordingly, the capacity and quality of the electrode and secondary battery can be improved.

[0119] In addition, since the crown value (N) of the rolling roller (100) used for hot rolling is equal to or greater than the first reference value and equal to or less than the second reference value, the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50).

[0120] According to embodiments of the present invention, in the rolling process (S510), the electrode sheet (50) is preheated by contacting the preheater (200) whose surface temperature is raised to the second temperature (T2) by the second heating unit (220), and then the electrode sheet (50) can be rolled by the rolling roller (100).

[0121] Accordingly, since the electrode sheet (50) is preheated before being rolled on the rolling roller (100), the temperature of the surface of the rolling roller (100) can be easily and stably maintained at the first temperature (T1). Accordingly, the rolling uniformity of the electrode sheet (50) can be improved, and thus the quality of the electrode and secondary battery can be improved.

[0122] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0123] FIG. 1 is a schematic side view of an electrode sheet hot rolling device according to one embodiment of the present invention.

[0124] Figure 2 is a front view showing the rolling roller of the hot rolling device of Figure 1.

[0125] Fig. 3 is a state diagram showing the state when an electrode sheet is rolled with the rolling roller of Fig. 2.

[0126] Figure 4 is a flow chart of a hot rolling method for an electrode sheet according to one embodiment of the present invention.

[0127] [Explanation of symbols]

[0128] 10: Electrode sheet hot rolling device

[0129] 50: Electrode sheet

[0130] 100: Rolling roller T1: First temperature

[0131] A: axis of rotation L: first length

[0132] D: First diameter K: Crown value

[0133] 120: First heating section

[0134] 200: Preheater T2: Second temperature

[0135] 220: Second heating unit

[0136] [Representative]

[0137] Fig. 1

[0138] The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily practice the technical idea of ​​the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0139] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0140] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0141] Hereinafter, the phrase "any configuration is placed on (or below)" a component or "on (or below)" a component may mean that any configuration is placed in contact with the upper surface (or lower surface) of said component, and that other configurations may be interposed between said component and any configuration placed on (or below) said component.

[0142] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0143] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consisting of" or "comprising" should not necessarily be construed to include all of the components or steps described in the specification, and should be construed to mean that some of the components or steps may not be included, or that additional components or steps may be included.

[0144]

[0145] Fig. 1 is a schematic side view of an electrode sheet hot rolling device according to one embodiment of the present invention. Fig. 2 is a front view showing a rolling roller of the hot rolling device of Fig. 1. Fig. 3 is a state diagram showing a state when an electrode sheet is rolled with the rolling roller of Fig. 2. Fig. 4 is a flow chart of an electrode sheet hot rolling method according to one embodiment of the present invention.

[0146]

[0147] [Electrode sheet hot rolling equipment]

[0148] Referring to Fig. 1, the electrode sheet hot rolling device (10) may include a rolling roller (100) and a first heating unit (120). The electrode sheet hot rolling device (10) may include a preheater (200) and a second heating unit (220).

[0149] The rolling roller (100) can roll the electrode sheet (50). Here, the electrode sheet (50) may be a composite layer including an electrode active material applied to a sheet-shaped electrode current collector (electrode foil). The rolling roller (100) will be described later.

[0150] The first heating unit (120) can heat the rolling roller (100). The first heating unit (120) can increase the temperature of the surface of the rolling roller (100) in contact with the electrode sheet (50) to the first temperature (T1).

[0151] The preheater (200) can come into contact with the electrode sheet (50). The preheater (200) can preheat the electrode sheet (50).

[0152] The preheater (200) may be a preheating roller.

[0153] Accordingly, the electrode sheet (50) can be effectively preheated.

[0154] The second heating unit (220) can heat the preheater (200). The second heating unit (220) can increase the temperature of the surface of the preheater (200) in contact with the electrode sheet (50) to the second temperature (T2).

[0155] The aforementioned rolling roller (100) can roll an electrode sheet (50) preheated by a preheater (200).

[0156] Accordingly, since the electrode sheet (50) is preheated before being rolled on the rolling roller (100), the temperature of the surface of the rolling roller (100) can be easily and stably maintained at the first temperature (T1). Accordingly, the rolling uniformity of the electrode sheet (50) can be improved, and thus the quality of the electrode and secondary battery can be improved.

[0157] The first temperature (T1) may be higher than or equal to the second temperature (T2).

[0158] Accordingly, since the temperature of the surface of the rolling roller (100) is higher than or equal to the temperature of the surface of the preheater (200), the temperature of the surface of the rolling roller (100) can be easily and stably maintained at the first temperature (T1). Accordingly, the rolling uniformity of the electrode sheet (50) can be improved, and thus the quality of the electrode and secondary battery can be improved.

[0159]

[0160] [Roller]

[0161] Referring further to FIGS. 2 and 3, the rolling roller (100) may be a known crown roller. Accordingly, the radius of the first cross-section of the axial central portion of the rolling roller (100) may be larger than the radius of the second cross-section of one axial end of the rolling roller (100) and the radius of the third cross-section of the other axial end.

[0162] The rolling roller (100) may have a first length (L) in the axial direction. The rolling roller (100) may have a first diameter (D) which is the diameter of the first cross section.

[0163] The crown value (N) of the rolling roller (100) may be a value obtained by subtracting the radius of the second or third cross-section from the radius of the first cross-section. If the crown value (N) of the rolling roller (100) in hot rolling is set to an appropriate value, the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50) even if the rolling roller (100) is bent / deformed (Fig. 3).

[0164] The crown value (N) of the rolling roller (100) may be greater than or equal to the first reference value and less than or equal to the second reference value. The second reference value may be greater than the first reference value.

[0165] The first reference value can be greater than 0.

[0166] The first reference value may be 0.001 mm.

[0167] Accordingly, since the electrode sheet (50) is hot rolled with a crown-endowed rolling roller (100), the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50).

[0168] The second reference value may have a value calculated by the following mathematical formula 1.

[0169]

[0170] [Mathematical Formula 1]

[0171]

[0172] Here, C1 may be 0.0155 mm. L may be a first length (L). D may be a first diameter (D). For example, the crown value (N) of a rolling roller (100) having a first length (L) of 800 mm and a first diameter (D) of 750 mm may be greater than 0 and less than or equal to about 20 um (the first reference value).

[0173] Accordingly, since the electrode sheet (50) is hot rolled with a crown-endowed rolling roller (100), the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50). Accordingly, the capacity and quality of the electrode and secondary battery can be improved.

[0174] In addition, it is possible to provide an appropriate range of the crown value (N) of the rolling roller (100) used for hot rolling of the electrode sheet (50). That is, since the crown value (N) of the rolling roller (100) used for hot rolling is equal to or greater than the first reference value and equal to or less than the second reference value, the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50).

[0175] In relation to this, since the appropriate rolling strength of the rolling roller (100) may differ when the electrode sheet (50) is hot rolled and cold rolled, the degree to which the rolling roller (100) bends / deforms during rolling may differ. Accordingly, the appropriate crown value (N) of the rolling roller (100) used in hot rolling may be different from the appropriate crown value (N) of the rolling roller (100) used in cold rolling. The present invention provides an appropriate crown value (N) of the rolling roller (100) used in hot rolling.

[0176] Meanwhile, the second reference value may be 20 um (micrometer) regardless of mathematical expression 1.

[0177] Accordingly, the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50).

[0178] The crown value (N) may be greater than or equal to a third reference value that is greater than the first reference value, and may be less than or equal to a fourth reference value that is greater than the third reference value and less than the second reference value.

[0179] The third reference value and the fourth reference value may have values ​​calculated by the following mathematical expressions 2 and 3.

[0180]

[0181] [Equation 2]

[0182]

[0183] Here, C2 may be 0.0046 mm. L may be the first length (L). D may be the first diameter (D).

[0184]

[0185] [Equation 3]

[0186]

[0187] Here, C3 may be 0.007 mm. L may be a first length (L). D may be a first diameter (D). For example, the crown value (N) of a rolling roller (100) having a first length (L) of 800 mm and a first diameter (D) of 750 mm may be approximately 6 um (third reference value) or more and 9 um (fourth reference value) or less.

[0188] Accordingly, the optimal range of the crown value (N) of the rolling roller (100) used for hot rolling of the electrode sheet (50) can be provided. That is, since the crown value (N) of the rolling roller (100) used for hot rolling is equal to or greater than the third reference value and equal to or less than the fourth reference value, the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made more consistent in the width direction of the electrode sheet (50).

[0189] Meanwhile, the third and fourth reference values ​​may be 6 um and 9 um, respectively, regardless of mathematical expressions 2 and 3.

[0190] Accordingly, while the electrode sheet (50) is rolled at a high density, the thickness of the electrode sheet (50) can be made more consistent in the width direction of the electrode sheet (50).

[0191] The optimal value of the crown value (N) can be calculated by the mathematical expression 4 below.

[0192]

[0193] [Equation 4]

[0194]

[0195] Here, C4 may be 0.0058 mm. L may be a first length (L). D may be a first diameter (D). For example, the optimal value of the crown value (N) of a rolling roller (100) having a first length (L) of 800 mm and a first diameter (D) of 750 mm may be approximately 7.5 μm.

[0196] Accordingly, the optimal value of the crown value (N) of the rolling roller (100) used for hot rolling of the electrode sheet (50) can be provided. That is, since the crown value (N) of the rolling roller (100) used for hot rolling is the optimal value, the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made more consistent in the width direction of the electrode sheet (50).

[0197] Meanwhile, the above optimal value may be 7.5 um regardless of mathematical expression 4.

[0198] Accordingly, while the electrode sheet (50) is rolled at a high density, the thickness of the electrode sheet (50) can be made more consistent in the width direction of the electrode sheet (50).

[0199] Mathematical expressions 1, 2, 3 and 4 can be created based on the second moment of section.

[0200] The rolling roller (100) can be coupled to a rotation shaft (A). The rolling roller (100) can be supported at two axial points (P1, P2) by the rotation shaft (A) during rolling (Fig. 2).

[0201] The rolling roller (100) may have shapes of one side and the other side symmetrical with respect to the midpoint of the two points (P1, P2) in the axial direction.

[0202] Accordingly, the second reference value, the third reference value, the fourth reference value, and / or the optimal value calculated by mathematical expressions 1, 2, 3, and / or 4 can be made accurate. Accordingly, the rolling roller (100) can have a more appropriate crown value (N).

[0203] This may be because mathematical expressions 1, 2, 3 and / or 4 were created assuming that the shapes of one side and the other side of the rolling roller (100) are symmetrical with respect to the midpoint of the two points (P1, P2) in the axial direction.

[0204] The above first cross-section may be a cross-section perpendicular to the axial direction at the midpoint.

[0205] Accordingly, the second reference value, the third reference value, the fourth reference value, and / or the optimal value calculated by mathematical expressions 1, 2, 3, and / or 4 can be made accurate. Accordingly, the rolling roller (100) can have a more appropriate crown value (N).

[0206] This may be because mathematical expressions 1, 2, 3 and / or 4 were created assuming that the first cross-section is a cross-section perpendicular to the axial direction at the midpoint.

[0207] The second and third cross sections may be cross sections perpendicular to the axial direction at the two points (P1, P2), respectively.

[0208] Accordingly, the second reference value, the third reference value, the fourth reference value, and / or the optimal value calculated by mathematical expressions 1, 2, 3, and / or 4 can be made accurate. Accordingly, the rolling roller (100) can have a more appropriate crown value (N).

[0209] This may be because Mathematical Expressions 1, 2, 3 and / or 4 were created assuming that the second and third cross sections are cross sections perpendicular to the axial direction at the two points (P1, P2), respectively.

[0210] The first length (L) may correspond to the axial distance between the two points (P1, P2).

[0211] Accordingly, the second reference value, the third reference value, the fourth reference value, and / or the optimal value calculated by mathematical expressions 1, 2, 3, and / or 4 can be made accurate. Accordingly, the rolling roller (100) can have a more appropriate crown value (N).

[0212] This may be because mathematical expressions 1, 2, 3 and / or 4 were created assuming that the first length (L) corresponds to the axial distance between the two points (P1, P2).

[0213]

[0214] [Hot rolling method for electrode sheets]

[0215] Referring to FIG. 4, the electrode sheet hot rolling method according to one embodiment of the present invention may include a rolling process (S510).

[0216] In the rolling process (S510), the electrode sheet (50) can be rolled by a rolling roller (100) having a crown value (N) equal to or greater than the first reference value and equal to or less than the second reference value. At this time, rolling can be performed while the temperature of the surface of the rolling roller (100) is raised to the first temperature (T1) by the first heating unit (120).

[0217] Accordingly, since the electrode sheet (50) is hot rolled with a crown-endowed rolling roller (100), the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50). Accordingly, the capacity and quality of the electrode and secondary battery can be improved.

[0218] In addition, since the crown value (N) of the rolling roller (100) used for hot rolling is equal to or greater than the first reference value and equal to or less than the second reference value, the electrode sheet (50) can be rolled at a high density while the thickness of the electrode sheet (50) can be made constant in the width direction of the electrode sheet (50).

[0219] Here, after preheating the electrode sheet (50) with a preheater (200), the electrode sheet (50) can be rolled with a rolling roller (100). When preheating the electrode sheet (50) with the preheater (200), the preheating can be performed in a state where the temperature of the surface of the preheater (200) is raised to a second temperature (T2) by the second heating unit (220).

[0220] Accordingly, since the electrode sheet (50) is preheated before being rolled on the rolling roller (100), the temperature of the surface of the rolling roller (100) can be easily and stably maintained at the first temperature (T1). Accordingly, the rolling uniformity of the electrode sheet (50) can be improved, and thus the quality of the electrode and secondary battery can be improved.

[0221]

[0222] It should be understood that the above-described embodiments are illustrative in all respects and not restrictive, and the scope of the present invention will be determined by the claims that follow, rather than by the detailed description set forth above. Furthermore, the meaning and scope of the claims that follow, as well as all possible modifications and variations derived from their equivalent concepts, should be construed as encompassing the scope of the present invention.

[0223] Although the present invention has been described with reference to the drawings exemplified above, it is to be understood that the present invention is not limited to the embodiments and drawings disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical idea of ​​the present invention. Furthermore, even if the operational effects according to the configuration of the present invention have not been explicitly described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be acknowledged.

Claims

1. A rolling roller (100) for rolling an electrode sheet (50); and It includes a first heating unit (120) that heats the rolling roller (100) and raises the temperature of the surface of the rolling roller (100) that comes into contact with the electrode sheet (50) to a first temperature (T1). The above rolling roller (100) is a crown roller, and accordingly, the radius of the first cross-section of the axial central portion of the rolling roller (100) is larger than the radius of the second cross-section of one axial end of the rolling roller (100) and the radius of the third cross-section of the other axial end, and has a first length (L) in the axial direction, and the first cross-section has a first diameter (D). The crown value (N) of the rolling roller (100), which is a value obtained by subtracting the radius of the second or third cross-section from the radius of the first cross-section, is equal to or greater than the first reference value and equal to or less than the second reference value that is greater than the first reference value. The above first reference value is greater than 0, The above second reference value has a value calculated by the following mathematical formula 1. Electrode sheet hot rolling machine. [Mathematical Formula 1] (Here, C1 is 0.0155 mm, L is the first length, and D is the first diameter) 2. In claim 1, The crown value (N) is greater than or equal to a third reference value that is greater than the first reference value, and less than or equal to a fourth reference value that is greater than the third reference value and less than the second reference value. An electrode sheet hot rolling device, wherein the third and fourth reference values have values calculated by the following mathematical expressions 2 and 3, respectively. [Equation 2] (Here, C2 is 0.0046 mm, L is the first length, and D is the first diameter) [Equation 3] (Here, C3 is 0.007 mm, L is the first length, and D is the first diameter) 3. In claim 2, The above crown value (N) is an optimal value that is greater than or equal to the third reference value and less than or equal to the fourth reference value, An electrode sheet hot rolling device having the above optimal value as calculated by the following mathematical formula 4. [Equation 4] (Here, C4 is 0.0058 mm, L is the first length, and D is the first diameter) 4. In any one of claims 1 to 3, The above rolling roller (100) is a hot rolling device that is coupled to a rotation axis (A), and two points (P1, P2) in the axial direction are supported by the rotation axis (A) during rolling, and the shapes of one side and the other side are symmetrical with respect to the midpoint of the two points (P1, P2) in the axial direction.

5. In claim 4, A hot rolling device, wherein the first cross-section is a cross-section perpendicular to the axial direction at the midpoint.

6. In any one of claims 1 to 3, The above rolling roller (100) is coupled to a rotation axis (A), and two points (P1, P2) in the axial direction are supported by the rotation axis (A) during rolling. A hot rolling device, wherein the second and third cross sections are cross sections perpendicular to the axial direction at the two points (P1, P2), respectively.

7. In any one of claims 1 to 3, The above rolling roller (100) is coupled to a rotation axis (A), and two points (P1, P2) in the axial direction are supported by the rotation axis (A) during rolling. An electrode sheet hot rolling device, wherein the first length (L) corresponds to the axial distance between the two points (P1, P2).

8. A rolling roller (100) for rolling the electrode sheet (50); and It includes a first heating unit (120) that heats the rolling roller (100) and raises the temperature of the surface of the rolling roller (100) that comes into contact with the electrode sheet (50) to a first temperature (T1). The above rolling roller (100) is a crown roller, and accordingly, the radius of the first cross-section of the axial central portion of the rolling roller (100) is larger than the radius of the second cross-section of one axial end of the rolling roller (100) and the radius of the third cross-section of the other axial end. The crown value (N) of the rolling roller (100), which is a value obtained by subtracting the radius of the second or third cross-section from the radius of the first cross-section, is equal to or greater than the first reference value and equal to or less than the second reference value that is greater than the first reference value. The above first reference value is greater than 0, The above second reference value is 20um, Electrode sheet hot rolling machine.

9. In claim 8, The crown value (N) is greater than or equal to a third reference value that is greater than the first reference value, and less than or equal to a fourth reference value that is greater than the third reference value and less than the second reference value. An electrode sheet hot rolling device, wherein the third and fourth reference values are 6 um and 9 um, respectively.

10. In claim 9, The above crown value (N) is an optimal value that is greater than or equal to the third reference value and less than or equal to the fourth reference value, The above optimal value is 7.5 um, an electrode sheet hot rolling device.

11. In any one of claims 1 to 10, A preheater (200) that comes into contact with the electrode sheet (50) and preheats the electrode sheet (50); and It includes a second heating unit (220) that heats the preheater (200) and raises the temperature of the surface of the preheater (200) in contact with the electrode sheet (50) to a second temperature (T2). The above rolling roller (100) is an electrode sheet hot rolling device that rolls the electrode sheet (50) preheated by the preheater (200).

12. In claim 11, An electrode sheet hot rolling device wherein the first temperature (T1) is higher than or equal to the second temperature (T2).

13. In claim 11, The above preheater (200) is a preheating roller, an electrode sheet hot rolling device.

14. In any one of claims 1 to 13, An electrode sheet hot rolling device, wherein the above first reference value is 0.001 mm.

15. In a method for hot rolling an electrode sheet using an electrode sheet hot rolling device according to any one of claims 1 to 14, The electrode sheet (50) is rolled by the rolling roller (100) having the crown value (N) equal to or greater than the first reference value and equal to or less than the second reference value, and includes a rolling process (S510) in which the temperature of the surface of the rolling roller (100) is increased to the first temperature (T1) by the first heating unit (120). Electrode sheet hot rolling method.

16. In claim 15, An electrode sheet hot rolling method in which, in the above rolling process (S510), the electrode sheet (50) is preheated by contacting the preheater (200) whose surface temperature is raised to a second temperature (T2) by the second heating unit (220), and then the electrode sheet (50) is rolled by the rolling roller (100).

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