Rolling roll and electrode rolling device including same

Abstract

The present invention relates to a rolling roll and an electrode rolling device including the same. The rolling roll according to one embodiment of the present invention includes a rotating shaft, a pair of roll units mounted on the rotating shaft at a predetermined interval, and an induction heating roll disposed between the pair of roll units, mounted on the rotating shaft, and configured to be induction heated when the rotating shaft rotates, the induction heating roll including an induction coil and a main body surrounding the induction coil.

Description

[Technical field]

[0001] The present invention relates to a rolling roll and an electrode rolling device including the same, and more particularly, to a rolling roll and an electrode rolling device capable of preventing wrinkles in an uncoated portion of an electrode sheet by providing heat to the uncoated portion in a rolling process of the electrode sheet.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0066839 dated May 31, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference. [Background technology]

[0003] As the application fields of secondary batteries expand, the demand for higher capacity secondary batteries is rapidly increasing. Research on technology to increase the loading amount of electrode active material is progressing as a method to increase the capacity of secondary batteries. However, increasing the loading amount of electrode active material increases the volume of the electrode. In this case, a process of rolling the electrode at a higher pressure is required to reduce the volume of the electrode.

[0004] 1 and 2 are diagrams for explaining a process of rolling an electrode sheet using a conventional rolling roll.

[0005] 1 and 2, an electrode substrate 10 has a coated portion 12 to which a positive or negative electrode active material is applied, and a non-coated portion 11 to which no electrode active material is applied. The non-coated portion 11 is a portion that is not coated with an electrode active material.

[0006] Referring to Figure 2, the coating portion 12 is arranged in a line along the running direction MD of the electrode substrate 10, and multiple coating portions 12 can be arranged along the width direction W of the electrode substrate 10, with an uncoated portion 11 located between two adjacent coating portions 12.

[0007] The electrode substrate 10 undergoes a rolling process while passing through a pair of rolling rollers 21 and 22. At this time, the rolling rollers 21 and 22 come into contact with the coating portion 12 and press the coating portion 12. In this manner, the density of the coating portion 12 of the electrode substrate 10 increases and the volume decreases through the rolling process.

[0008] However, there is a problem that the uncoated portion 11 may be severely wrinkled or broken during the process of rolling the electrode substrate 10 under high pressure. Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide a rolling roll capable of preventing wrinkles in an uncoated portion of an electrode sheet by applying heat to the uncoated portion in a rolling process of the electrode sheet, and an electrode rolling apparatus including the same. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, a rolling roll according to one embodiment of the present invention includes a rotating shaft, a pair of roll units mounted on the rotating shaft at a predetermined interval, and an induction heating roll disposed between the pair of roll units, mounted on the rotating shaft, and configured to be induction heated when the rotating shaft rotates, the induction heating roll including an induction coil and a main body surrounding the induction coil.

[0011] The induction coil may be configured to generate heat when an alternating current is applied to the induction heating roll body. The induction heating roll body may have a heating roll surface that is heated by heat transferred from the induction coil. Heat may be transferred to the outside through the heating roll surface.

[0012] The induction heating roll includes an iron core, and the induction coil is disposed so as to surround the iron core. One or more induction coils may be provided.

[0013] In addition, the induction coil is electrically connected to a power supply unit, and when an AC voltage is applied to the induction coil through the power supply unit, an alternating magnetic flux is generated, which generates an induced current, and the main body can generate Joule heat due to the induced current. In this structure, the generated heat can be transferred to the outside through the heating roll surface. In addition, when the induction heating roll is located on the non-coated portion of the electrode sheet, the heat can be transferred toward the non-coated portion of the electrode sheet during the rolling process, making it easy to perform forced elongation on the non-coated portion.

[0014] The pair of roll units may include a first roll unit disposed on one side of the induction heating roll and having a first roll surface that contacts the workpiece, and a second roll unit disposed on the other side of the induction heating roll and having a second roll surface that contacts the workpiece. The induction heating roll is disposed between the first roll unit and the second roll unit. At this time, the first roll unit contacts one surface of the induction heating roll, and the second roll unit contacts the other surface of the induction heating roll.

[0015] The first roll unit may have a first inner surface in contact with the induction heating roll and a first outer surface in the opposite direction to the first inner surface. The first inner surface and the first outer surface may be provided in parallel. In this case, the first roll surface connects the first inner surface and the first outer surface. The first inner surface may have the same diameter as the diameter of the induction heating roll. In such a structure, the heating roll surface of the induction heating roll and the first roll surface of the first roll unit may be connected without a step.

[0016] The first roll portion may be provided such that a diameter of the first outer surface is smaller than a diameter of the first inner surface.

[0017] In one embodiment, the first roll portion may have a truncated cone shape in which the cross-sectional diameter of the first roll surface decreases from the first inner surface to the first outer surface.

[0018] The first roll portion may be provided such that the radius of the first inner surface is larger than the radius of the first outer surface by within a range of 0.3 mm to 0.5 mm.

[0019] The first roll portion may include a first core portion coupled to the rotating shaft, and a first surface portion surrounding the first core portion and having a thermal conductivity lower than that of the first core portion.

[0020] The second roll unit may have a second inner surface in contact with the induction heating roll and a second outer surface in the opposite direction to the second inner surface. The second inner surface may have the same diameter as the diameter of the induction heating roll. The second inner surface and the second outer surface may be provided in parallel. In this case, the second roll surface may connect the second inner surface and the second outer surface. In such a structure, the heating roll surface of the induction heating roll and the second roll surface of the second roll unit may be connected without a step.

[0021] The second roll portion may be provided such that the diameter of the second outer surface is smaller than the diameter of the second inner surface.

[0022] In one embodiment, the second roll portion may have a truncated cone shape in which the cross-sectional diameter of the second roll surface decreases from the second inner surface to the second outer surface.

[0023] The second roll portion may be provided such that the radius of the second inner surface is larger than the radius of the second outer surface by within a range of 0.3 mm to 0.5 mm.

[0024] The second roll portion may also include a second core portion coupled to the rotating shaft, and a second surface portion surrounding the second core portion and having a thermal conductivity lower than that of the second core portion.

[0025] Moreover, the pair of roll units can be disposed symmetrically with respect to the induction heating roll.

[0026] In addition, an electrode rolling device according to an embodiment of the present invention includes a pair of rolling rolls that are disposed in a traveling path of an electrode sheet having a coated portion and an uncoated portion and press the electrode sheet upward and downward, and a control unit that controls the operation of each of the rolling rolls.

[0027] Each rolling roll includes a rotating shaft, a pair of roll sections mounted on the rotating shaft at a predetermined interval and each positioned on the coated portion of the electrode sheet, and an induction heating roll disposed between the pair of roll sections, mounted on the rotating shaft, positioned on the uncoated portion of the electrode sheet, and including an induction coil arranged to be induction heated when the rotating shaft rotates, and a main body surrounding the induction coil.

[0028] The induction coil is provided to generate heat when an alternating current is applied thereto, and the main body of the induction heating roll has a heating roll surface that is heated by heat transferred from the induction coil and is disposed opposite the non-coated portion.

[0029] In addition, the pair of roll units may each include a first roll unit disposed on one side of the induction heating roll and having a first roll surface in contact with the workpiece to be rolled, and a second roll unit disposed on the other side of the induction heating roll and having a second roll surface in contact with the workpiece to be rolled.

[0030] In addition, the first roll portion has a first inner surface that is in contact with the induction heating roll and has the same diameter as the diameter of the induction heating roll, and a first outer surface in the opposite direction to the first inner surface, and a first roll surface that connects the first inner surface and the first outer surface.

[0031] In addition, the second roll portion has a second inner surface that is in contact with the induction heating roll and has the same diameter as the diameter of the induction heating roll, and a second outer surface in the opposite direction to the second inner surface, and the second roll surface connects the second inner surface and the second outer surface.

[0032] The first roll portion is provided such that the diameter of the first outer surface is smaller than the diameter of the first inner surface, and the second roll portion is provided such that the diameter of the second outer surface is smaller than the diameter of the second inner surface.

[0033] The first roll portion may include a first core portion coupled to the rotating shaft, and a first surface portion surrounding the first core portion and having a thermal conductivity lower than that of the first core portion.

[0034] The second roll portion may also include a second core portion coupled to the rotating shaft, and a second surface portion surrounding the second core portion and having a thermal conductivity lower than that of the second core portion. Effect of the Invention

[0035] As described above, according to at least one embodiment of the present invention, the rolling roll and the electrode rolling device including the same can forcibly stretch the uncoated portion of the electrode sheet by providing heat to the uncoated portion of the electrode sheet when the rolling roll presses the coated portion of the electrode sheet, thereby preventing wrinkles in the uncoated portion during the rolling process of the electrode sheet. [Brief description of the drawings]

[0036] [Figure 1] FIG. 1 is a diagram for explaining a process of rolling an electrode sheet using a conventional rolling roll. [Diagram 2] FIG. 1 is a diagram for explaining a process of rolling an electrode sheet using a conventional rolling roll. [Diagram 3] FIG. 2 is a diagram illustrating a process of rolling an electrode sheet using a rolling roll according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram illustrating a process of rolling an electrode sheet using a rolling roll according to an embodiment of the present invention. [Diagram 5] FIG. 2 is a cross-sectional view of a rolling roll according to one embodiment of the present invention. [Figure 6] FIG. 2 is a diagram for explaining a structure of a reduction roll according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] Hereinafter, a rolling roll and an electrode rolling apparatus including the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0038] In addition, regardless of the drawing symbols, the same or similar reference numbers will be used for the same or corresponding components, and duplicate descriptions will be omitted. For convenience of explanation, the size and shape of each component shown may be exaggerated or reduced.

[0039] 3 and 4 are diagrams for explaining the process of rolling an electrode sheet using a rolling roll according to one embodiment of the present invention, FIG. 5 is a cross-sectional view of the rolling roll according to one embodiment of the present invention, and FIG. 6 is a diagram for explaining the structure of the rolling roll according to one embodiment of the present invention.

[0040] 3 and 4, an electrode rolling apparatus 100 according to an embodiment of the present invention includes a pair of rolls 110, 120 and a control unit 130. The control unit 130 controls the operation of each of the rolls 110, 120.

[0041] Each of the rolling rolls 110, 120 includes a rotating shaft 111 and a pair of roll units 115, 117 that are mounted on the rotating shaft 111 at a predetermined interval and positioned on the coating unit 12 of the electrode sheet 10. Each of the rolling rolls 110, 120 also includes an induction heating roll 113 that is disposed between the pair of roll units 115, 117 and mounted on the rotating shaft 111.

[0042] The induction heating roll 113 is located on the uncoated portion 11 of the electrode sheet 10 and includes an induction coil 113b that is inductively heated when the rotating shaft 111 rotates, and a body 113a that surrounds the induction coil 113b.

[0043] The pair of pressure rolls 110, 120 are disposed on the travel path MD of the electrode sheet 10, and are disposed above and below the electrode sheet 10. The pair of pressure rolls 110, 120 are disposed so as to press the electrode sheet 10 upward and downward.

[0044] The electrode rolling apparatus 100 may include a power supply unit 150 electrically connected to the induction coil 113b, and a driving unit 140 (e.g., a motor) for rotating the rotating shaft 111 of the rolling rolls 110 and 120. The power supply unit 150 and the driving unit 140 may be controlled by a control unit 130.

[0045] 1 and 2, the electrode sheet 10 has a coating portion 12 and an uncoated portion 11. The induction heating roll 113 is positioned on the uncoated portion 11 of the electrode sheet 10 so as to transfer heat to the uncoated portion 11 of the electrode sheet 10.

[0046] The induction coil 113b is electrically connected to a power supply unit 150. When an AC voltage is applied to the induction coil 113b through the power supply unit 150, an induced current is generated, and the body 113a can generate Joule heat due to the induced current. In addition, when the induction heating roll 113 is positioned on the non-coated portion 11 of the electrode sheet 10, the induction heating roll 113 transfers heat to the non-coated portion 11 of the electrode sheet 10 during the process in which the pair of roll units roll the coating unit 12, so that the non-coated portion 11 can be easily forced to stretch.

[0047] The pair of pressure rolls 110, 120 roll the electrode sheet 10 under pressure while rotating in opposite directions.

[0048] The pair of rolls 110, 120 have the same structure and operation method. For convenience of explanation, the present embodiment will mainly describe the upper roll 110 with reference to FIG.

[0049] A rolling roll 110 according to one embodiment of the present invention includes a rotating shaft 111 , an induction heating roll 113 , and a pair of roll portions 115 and 117 .

[0050] 4 and 5, the rolling rolls 110, 120 include a rotating shaft 111 and a pair of roll units 115, 117 mounted on the rotating shaft 111 at a predetermined interval and positioned on the coating unit 12 of the electrode sheet 10. Each of the rolling rolls 110, 120 includes an induction heating roll 113 disposed between the pair of roll units 115, 117 and mounted on the rotating shaft 111.

[0051] The induction heating roll 113 is located on the uncoated portion 11 of the electrode sheet 10 and includes an induction coil 113b that is inductively heated when the rotating shaft 111 rotates, and a body 113a that surrounds the induction coil 113b.

[0052] The rotating shaft 111 is provided along the width direction w of the electrode sheet 10. The rotation direction and rotation speed of the rotating shaft 111 can be controlled by a control unit 130.

[0053] The induction heating roll 113 is attached to the rotating shaft 111 so as to be disposed at a position facing the uncoated portion 11 of the electrode sheet 10, and is induction heated when the rotating shaft 111 rotates, thereby transferring heat to the uncoated portion 11. For example, when the uncoated portion 11 is provided at the center of the width direction w of the electrode sheet 10, the induction heating roll 113 may be attached to the center of the rotating shaft 111. During the rolling process, the control unit 130 may rotate the rolling roll 110 through the driving unit 140, and apply an AC current to the induction coil 113b through the power supply unit 150.

[0054] The induction heating roll 113 includes a main body 113a attached to a rotating shaft 111, and an induction coil 113b disposed within the main body 113a.

[0055] The induction coil 113b is provided so as to generate heat when an alternating current is applied thereto, and the main body 113a of the induction heating roll 113 has a heating roll surface 113a-1 which is heated by the heat transferred from the induction coil 113b.

[0056] 5 and 6, the body 113a is mounted on a rotating shaft 111 so as to surround the induction coil 113b. The body 113a has a roll width Wr corresponding to the width of the non-coated portion 11, and has a heating roll surface 113a-1 that is heated by heat transferred from the induction coil 113b.

[0057] Furthermore, the main body 113a has a diameter larger than the diameter of the rotating shaft 111. The main body 113a has a cylindrical shape with a circular cross section. The main body 113a is attached to the rotating shaft 111 so as to surround the central portion of the rotating shaft 111. As an example, the main body 113a may be formed of a stainless steel material.

[0058] In addition, induction coil 113b is built into main body 113a, and generates heat while generating a magnetic field when AC current is applied. The heat generated by induction coil 113b heats main body 113a to a predetermined temperature. In addition, the heat is transferred to the outside of the main body (non-coated portion) via heating roll surface 113a-1.

[0059] In the rolling process of the electrode sheet 10, the induction heating roll 113 is positioned opposite the uncoated portion 11 and transfers heat to the uncoated portion 11, thereby forcibly stretching the uncoated portion 11, thereby preventing wrinkles in the uncoated portion 11.

[0060] The pair of roll units 115, 117 are provided on both sides of the induction heating roll 113. The pair of roll units 115, 117 are attached to the rotating shaft 111, and pressurize and roll the electrode sheet 10 when the rotating shaft 111 rotates.

[0061] When the induction heating roll 113 is provided in the center of the rotating shaft 111, the pair of roll units 115, 117 are each attached to the rotating shaft 111 with the induction heating roll 113 sandwiched between them. In this embodiment, for convenience of explanation, the pair of roll units are designated as a first roll unit 115 and a second roll unit 117 according to their installation positions.

[0062] The pair of roll units 115, 117 includes a first roll unit 115 disposed on one side of the induction heating roll 113 and having a first roll surface that contacts the object to be rolled (the coating portion of the electrode sheet), and a second roll unit 117 disposed on the other side of the induction heating roll 113 and having a second roll surface that contacts the object to be rolled (the coating portion of the electrode sheet).

[0063] Referring to Figures 3 and 4, the electrode rolling device 100 performs a rolling process of two coating parts 12 through a pair of roll parts 115 and 117, and can apply heat to the plain part 11 located between the two coating parts 12 through an induction heating roll 113.

[0064] 5 and 6, the first roll unit 115 may be attached to the rotating shaft 111 on one side of the induction heating roll 113. The first roll unit 115 may be attached to the rotating shaft 111 so as to be separable from the induction heating roll 113.

[0065] The first roll unit 115 has a first roll surface 115c-3 that pressurizes and rolls the coating unit 12 when the rotating shaft 111 rotates, and the first roll surface 115c-3 can be connected to the heating roll surface 113a-1 without any step.

[0066] In addition, the first roll part 115 includes a first core part 115a and a first surface part 115b. Specifically, the first roll part 115 may include a first core part 115a coupled to the rotating shaft 111, and a first surface part 115b surrounding the first core part 115a and having a thermal conductivity lower than that of the first core part 115a.

[0067] In addition, the first core portion 115a may have a truncated cone structure. The first core portion 115a is attached to the rotating shaft 111, and may be made of stainless steel.

[0068] Moreover, first surface portion 115b is provided so as to surround first core portion 115a and has a thermal conductivity different from that of first core portion 115a. First surface portion 115b may be formed on the surface of first core portion 115a using a material having a thermal conductivity lower than that of first core portion 115a.

[0069] Referring to FIG. 6, the first roll portion 115 contacts the induction heating roll 113 and has a first inner side 115c-1 having the same diameter as the diameter of the induction heating roll 113, and a first outer side 115c-2 in the opposite direction to the first inner side 115c-1, and a first roll surface 115c-3 connects the first inner side 115c-1 and the first outer side 115c-2.

[0070] The first roll part 115 has a truncated cone shape having a first inner surface 115c-1, a first outer surface 115c-2, and a first roll surface 115c-3. Here, the first inner surface 115c-1 is a surface that comes into contact with one surface of the induction heating roll 113.

[0071] The first outer surface 115c-2 has a diameter smaller than that of the first inner surface 115c-1 and is a surface provided parallel to the first inner surface 115c-1. The first roll surface 115c-3 is a surface that surrounds the rotation shaft 111 and connects the first inner surface 115c-1 and the first outer surface 115c-2. The first roll surface 115c-3 is provided with the first surface portion 115b.

[0072] The first roll unit 115 has a structure in which the cross-sectional diameter of the first roll surface 115c-3 decreases from the first inner surface 115c-1 to the first outer surface 115c-2. The first roll unit 115 may be provided such that the diameter of the first inner surface 115c-1 is the same as the diameter of the induction heating roll 113.

[0073] In addition, the first roll portion 115 may be provided such that the diameter (or radius) of the first outer surface is smaller than the diameter (or radius) of the first inner surface.

[0074] The first roll portion 115 is provided such that the radius R1 of the first inner side is larger than the radius R2 of the first outer side by within a range of 0.3 mm to 0.5 mm. That is, the difference between the radius R1 of the first inner side 115c-1 and the radius R2 of the first outer side 115c-2 (R1-R2=t) is within a range of 0.3 mm to 0.5 mm.

[0075] In addition, the pair of roll units 115, 117 may be disposed symmetrically with respect to the induction heating roll 113. That is, the first and second roll units 115, 117 have a symmetrical configuration with respect to the induction heating roll 113.

[0076] The second roll unit 117 is attached to the rotating shaft 111 on the other side of the induction heating roll 113. The second roll unit 117 can be attached to the rotating shaft 111 so as to be separable from the induction heating roll 113. The second roll unit 117 is attached to the rotating shaft 111 spaced apart from the first roll unit 115 with the induction heating roll 113 interposed therebetween. The second roll unit 117 has a second roll surface 117c-3 that presses and rolls the coating unit 12 when the rotating shaft 111 rotates. In addition, the second roll surface 117c-3 can be connected to the heating roll surface 113a-1 without any step.

[0077] 5 and 6, the second roll part 117 includes a second core part 117a and a second surface part 117b. Specifically, the second roll part 117 may include a second core part 117a coupled to the rotating shaft 111, and a second surface part 117b surrounding the second core part 117a and having a thermal conductivity lower than that of the second core part 117a.

[0078] In addition, the second core portion 117a is provided in a truncated cone structure. The second core portion 117a is attached to the rotating shaft 111, and the second core portion 117a may be formed of the same material as the first core portion 115a.

[0079] Second surface portion 117b is provided to surround second core portion 117a and has a thermal conductivity different from that of second core portion 117a. Second surface portion 117b may be formed on the surface of second core portion 117a using a material having a thermal conductivity lower than that of second core portion 117a.

[0080] Referring to FIG. 6, the second roll portion 117 contacts the induction heating roll 113 and has a second inner side 117c-1 having the same diameter as the diameter of the induction heating roll, and a second outer side 117c-2 in the opposite direction to the second inner side 117c-1, and a second roll surface 117c-3 connects the second inner side 117c-1 and the second outer side 117c-2.

[0081] The second roll part 117 has a truncated cone shape having a second inner side surface 117c-1, a second outer side surface 117c-2, and a second roll surface 117c-3. Here, the second inner side surface 117c-1 is a surface that comes into contact with the other surface of the induction heating roll 113. The second roll part 117 can be provided such that the diameter of the second inner side surface 117c-1 is the same as the diameter of the induction heating roll 113.

[0082] The second outer side surface 117c-2 has a diameter (or radius) smaller than the diameter of the second inner side surface 117c-1, and is a surface provided parallel to the second inner side surface 117c-1.

[0083] In addition, the second roll portion 117 may be provided such that the diameter (or radius) of the second outer surface is smaller than the diameter (or radius) of the second inner surface.

[0084] The second roll portion 117 has a structure in which the cross-sectional diameter of the second roll surface 117c-3 decreases from the second inner surface 117c-1 to the second outer surface 117c-2. The second roll surface 117c-3 surrounds the rotation shaft 111 and connects the second inner surface 117c-1 and the second outer surface 117c-2. The second surface portion 117b is provided on the second roll surface 117c-3.

[0085] The second roll portion has a second inner surface radius R1 that is larger than a second outer surface radius R2 by within a range of 0.3 mm to 0.5 mm. That is, the difference between the radius R1 of the second inner surface 117c-1 and the radius R2 of the second outer surface 117c-2 (R1-R2=t) is within a range of 0.3 mm to 0.5 mm.

[0086] As described above, by including a pair of roll units 115, 117 that pressurize and roll the coating portion 12 of the electrode sheet 10, and the induction heating roll 113 that provides heat to the plain portion 11, it is possible to provide heat to the plain portion 11 during the rolling process of the electrode sheet 10, thereby preventing wrinkles in the plain portion 11.

[0087] The above-described embodiment of the present invention has been disclosed for illustrative purposes, and a person skilled in the art having ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions should be considered to fall within the scope of the appended claims. [Industrial Applicability]

[0088] According to at least one embodiment of the present invention, a rolling roll and an electrode rolling device including the same can provide heat to a plain portion of the electrode sheet when the rolling roll presses a coating portion of the electrode sheet, thereby forcibly stretching the plain portion and preventing wrinkles in the plain portion during the rolling process of the electrode sheet.

Claims

1. A rotation axis; A pair of roll units mounted on the rotating shaft at a predetermined interval; an induction heating roll including an induction coil disposed between the pair of roll portions, attached to the rotating shaft, and configured to be induction heated when the rotating shaft rotates, and a main body surrounding the induction coil.

2. The induction coil is configured to generate heat when an alternating current is applied thereto, The rolling roll according to claim 1 , wherein the body of the induction heating roll has a heated roll surface that is heated by heat transferred from the induction coil.

3. 2. The rolling roll according to claim 1, wherein the pair of roll units includes a first roll unit arranged on one side of the induction heating roll and having a first roll surface that contacts the workpiece to be rolled, and a second roll unit arranged on the other side of the induction heating roll and having a second roll surface that contacts the workpiece to be rolled.

4. the first roll portion is in contact with the induction heating roll and has a first inner surface having the same diameter as the diameter of the induction heating roll and a first outer surface opposite to the first inner surface; The roll according to claim 3 , wherein the first roll surface connects the first inner surface and the first outer surface.

5. The roll of claim 4 , wherein a diameter of the first outer side of the first roll portion is smaller than a diameter of the first inner side of the first roll portion.

6. 4. The rolling roll according to claim 3, wherein the first roll portion includes a first core portion coupled to the rotating shaft, and a first surface portion surrounding the first core portion and having a thermal conductivity lower than a thermal conductivity of the first core portion.

7. the second roll portion is in contact with the induction heating roll and has a second inner surface having the same diameter as the diameter of the induction heating roll and a second outer surface opposite to the second inner surface; The roll according to claim 3 , wherein the second roll surface connects the second inner side surface and the second outer side surface.

8. 8. The roll of claim 7, wherein a diameter of the second outer side surface of the second roll portion is smaller than a diameter of the second inner side surface.

9. 4. The rolling roll according to claim 3, wherein the second roll portion includes a second core portion coupled to the rotating shaft, and a second surface portion surrounding the second core portion and having a thermal conductivity lower than a thermal conductivity of the second core portion.

10. The reduction roll according to claim 1 , wherein the pair of roll portions are disposed symmetrically with respect to the induction heating roll.

11. A pair of rolling rolls are disposed in a traveling path of an electrode sheet having a coating portion and an uncoated portion, and press the electrode sheet upward and downward; A control unit for controlling the operation of each rolling roll, Each rolling roll is A rotation axis; A pair of roll units are mounted on the rotating shaft at a predetermined interval and positioned on the coating of the electrode sheet, respectively; an induction heating roll disposed between the pair of roll units, attached to the rotating shaft, positioned on the uncoated portion of the electrode sheet, and including an induction coil configured to be induction heated when the rotating shaft rotates, and a main body surrounding the induction coil.

12. The induction coil is configured to generate heat when an alternating current is applied thereto, The electrode rolling apparatus according to claim 11, wherein a body of the induction heating roll has a heating roll surface that is heated by heat transferred from the induction coil and is disposed opposite the uncoated portion.

13. The pair of roll units includes a first roll unit disposed on one side of the induction heating roll and having a first roll surface that contacts the rolling object, and a second roll unit disposed on the other side of the induction heating roll and having a second roll surface that contacts the rolling object, the first roll portion is in contact with the induction heating roll and has a first inner surface having the same diameter as the diameter of the induction heating roll and a first outer surface opposite to the first inner surface; The first roll surface connects the first inner surface and the first outer surface, the second roll portion is in contact with the induction heating roll and has a second inner surface having the same diameter as the diameter of the induction heating roll and a second outer surface opposite to the second inner surface; The electrode rolling apparatus according to claim 11 , wherein the second roll surface connects the second inner surface and the second outer surface.

14. a diameter of the first outer surface of the first roll portion is smaller than a diameter of the first inner surface of the first roll portion; 14. The electrode rolling apparatus of claim 13, wherein a diameter of the second outer side of the second roll portion is smaller than a diameter of the second inner side.

15. the first roll portion includes a first core portion coupled to the rotating shaft, and a first surface portion surrounding the first core portion and having a thermal conductivity lower than a thermal conductivity of the first core portion; 14. The electrode rolling apparatus according to claim 13, wherein the second roll portion includes: a second core portion coupled to the rotating shaft; and a second surface portion surrounding the second core portion and having a thermal conductivity lower than a thermal conductivity of the second core portion.

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