Laser slotting equipment for electrode plate and method for slotting electrode plate by using laser slotting equipment

Abstract

The present invention relates to a laser grooving apparatus for an electrode sheet and a method for grooving an electrode sheet using the same, and more particularly, to a laser grooving apparatus for an electrode sheet and a method for grooving an electrode sheet using the same, the laser grooving apparatus comprising: an unwinder, an electrode plate is wound on the unwinder; a slotting drum which is positioned at a predetermined distance from the unwinder and supports the supplied electrode sheet; the laser irradiator is used for slotting the electrode plate; and a rewinder that is positioned at a predetermined distance from the slotting drum and winds the slotted electrode sheet, in which the electrode sheet wound on the unwinder includes a first surface forming an inner surface and a second surface forming an outer surface, and the slotting drum is disposed to face the first surface of the electrode sheet.

Description

Technical Field

[0001] This application claims the benefit of priority from Korean Patent Application No. 2023-0038577, filed on March 24, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to a laser grooving device for an electrode sheet and an electrode grooving method using the same, and more particularly, to a laser grooving device for an electrode sheet and an electrode grooving method using the same, in which the arrangement of a laser irradiator and a grooving roller configured to groove the electrode sheet is determined based on the light reflectivity and curvature of the electrode sheet. Background Art

[0003] With the recent development of alternative energy sources due to air pollution and energy depletion caused by the use of fossil fuels, the demand for secondary batteries that can store the generated electrical energy has increased. Secondary batteries that can be charged and discharged are widely used in daily life. For example, secondary batteries are used in mobile devices, electric vehicles, and hybrid electric vehicles.

[0004] Due to the increased use and sophistication of mobile devices and the development of electric vehicles, the required capacity of secondary batteries, which are used as energy sources for various electronic devices inevitably used in modern society, has increased. To meet user needs, multiple battery cells are provided in small devices, while battery modules including multiple battery cells electrically connected to each other or battery packs including multiple battery modules are used in vehicles and the like.

[0005] The secondary battery may include a stacked-type electrode assembly configured such that flat electrode plates each having an electrode tab protruding from a periphery of at least one side thereof are stacked with a separator interposed therebetween.

[0006] In order to manufacture each flat electrode plate, a punching notching process or a laser notching process is used as a notching process for forming electrode tabs on the electrode sheet.

[0007] In the laser grooving process, the grooving quality may be affected by the orientation of the laser irradiator and the grooving drum relative to the outer surface of the electrode sheet, the position and orientation of the unwinder around which the electrode sheet is wound, and the like.

[0008] Poor groove quality may lead to problems such as poor groove size, tab folding, and uncut electrode sheets, which may reduce the yield of secondary batteries.

[0009] Furthermore, if the laser irradiator is located above the grooved electrode sheet in the same direction as the moving direction of the electrode sheet, contamination due to debris generated during the groove forming process may occur.

[0010] In this regard, patent document 1 discloses an apparatus for removing debris generated during the slotting of a secondary battery, wherein the apparatus includes a debris inspection unit and a debris removal unit, the debris inspection unit being configured to photograph the upper and lower surfaces of a slotted electrode pattern on a transfer path of an electrode film that has undergone a slotting process, and to calculate the position of debris present in the electrode pattern based on the photographed image, the debris removal unit being configured to blow air toward the position of the debris and to apply vacuum pressure based on information related to the position of the debris calculated by the debris inspection unit.

[0011] Patent Document 1 discloses a technology capable of removing debris generated during the notching process to prevent a short circuit in a secondary battery, but does not solve the problem of poor quality occurring during the notching process.

[0012] Therefore, there is a need for a technology capable of preventing groove defects during a groove forming process of forming an electrode tab, thereby minimizing a reduction in the yield of secondary batteries.

[0013] (Prior art literature)

[0014] (Patent Document 1) Korean Patent Application Publication No. 2022-0142148 (October 21, 2022) Summary of the Invention

[0015] Technical issues

[0016] The present invention is made in view of the above problems, and an object of the present invention is to provide a laser grooving device for an electrode sheet and an electrode sheet grooving method using the laser grooving device, which can suppress defects of the electrode sheet generated during the grooving process.

[0017] Technical Solution

[0018] In order to achieve the above-mentioned object, the laser slotting device for an electrode sheet according to the present invention comprises: an unwinder (100) around which an electrode sheet (10) is wound; a slotting roller (200) positioned to be spaced a predetermined distance from the unwinder (100), the slotting roller being configured to support the supplied electrode sheet (10); a laser irradiator (300) for slotting the electrode sheet (10); and a rewinder (400) positioned to be spaced a predetermined distance from the slotting roller (200), the rewinder being configured to wind the slotted electrode sheet (10), wherein the electrode sheet (10) wound around the unwinder (100) comprises a first surface (10a) constituting an inner surface and a second surface (10b) constituting an outer surface, and the slotting roller (200) is arranged to face the first surface (10a) of the electrode sheet (10).

[0019] In addition, in the laser grooving device for an electrode sheet according to the present invention, the first surface (10a) and the second surface (10b) of the electrode sheet (10) can have different light reflectivities, and the light reflectivity of the second surface (10b) can be lower than the light reflectivity of the first surface (10a).

[0020] Furthermore, in the laser slotting apparatus for an electrode sheet according to the present invention, the laser irradiator (300) may be located between the unwinder (100) and the slotting roller (200).

[0021] In addition, the laser slotting apparatus for an electrode sheet according to the present invention may further include a guide roller (500) configured to change the moving direction of the supplied electrode sheet (10), wherein the guide roller (500) may include a first guide roller (510) and a second guide roller (520) located between the unwinder (100) and the slotting drum (200).

[0022] Furthermore, in the laser slotting apparatus for an electrode sheet according to the present invention, the first guide roller (510) and the second guide roller (520) may be located at a higher position than the unwinder (100) and the slotting drum (200).

[0023] Furthermore, in the laser grooving apparatus for an electrode sheet according to the present invention, the first guide roller (510) and the second guide roller (520) may face the second surface (10b) of the electrode sheet (10).

[0024] Furthermore, in the laser slotting apparatus for an electrode sheet according to the present invention, the guide roller (500) may include a third guide roller (530) located below the slotting drum (200).

[0025] Furthermore, in the laser slotting apparatus for an electrode sheet according to the present invention, the rewinder (400) may be located behind the third guide roller (530).

[0026] Furthermore, in the laser grooving apparatus for an electrode sheet according to the present invention, the third guide roller (530) may face the first surface (10a) of the electrode sheet (10).

[0027] In addition, the laser grooving method for an electrode sheet according to the present invention includes the following steps: a first step of supplying the electrode sheet (10) wound around an unwinder (100) to a grooving roller (200); a second step of irradiating a laser beam toward the electrode sheet (10) in contact with the grooving roller (200) to groove the electrode sheet (10); and a third step of winding the grooved electrode sheet (10), wherein the electrode sheet (10) wound around the unwinder (100) includes a first surface (10a) constituting an inner surface and a second surface (10b) constituting an outer surface, and the grooving roller (200) can face the first surface of the electrode sheet.

[0028] In addition, in the laser grooving method for an electrode sheet according to the present invention, in the second step, a laser beam can be irradiated toward the second surface (10b) of the electrode sheet (10), and the first surface (10a) and the second surface (10b) of the electrode sheet (10) can have different light reflectivities, and the light reflectivity of the second surface (10b) is lower than the light reflectivity of the first surface (10a).

[0029] In addition, the laser grooving method for an electrode sheet according to the present invention may further include a first moving direction changing step of changing the moving direction of the supplied electrode sheet (10) between the first step and the second step, wherein the first moving direction changing step is performed by a first guide roller (510) and a second guide roller (520) located between the unwinder (100) and the grooving roller (200), and the first guide roller (510) and the second guide roller (520) can rotate in a manner facing the second surface (10b) of the electrode sheet (10).

[0030] In addition, the laser grooving method for an electrode sheet according to the present invention may further include a second moving direction changing step of changing the moving direction of the grooved electrode sheet (10) between the second step and the third step, wherein the second moving direction changing step is performed by a third guide roller (530) located behind the grooving roller (200), and the third guide roller (530) can rotate in a manner facing the first surface (10a) of the electrode sheet (10).

[0031] Furthermore, the present invention can provide various combinations of the above-mentioned solving means.

[0032] Beneficial effects

[0033] It is obvious from the above description that in the laser grooving device for electrode sheets and the electrode sheet grooving method using the laser grooving device according to the present invention, a laser irradiator is used to form electrode joints, thereby preventing problems such as poor grooving size and joint folding.

[0034] In addition, in the laser grooving apparatus for an electrode sheet and the electrode sheet grooving method using the laser grooving apparatus, the laser irradiator irradiates a laser beam toward a surface with low light reflectivity of one of the opposite surfaces of the electrode sheet, thereby reducing defects such as uncut surfaces.

[0035] In addition, in the laser grooving equipment for electrode sheets and the electrode grooving method using the laser grooving equipment, the moving direction of the grooved electrode sheet is the same as the opposite direction of the setting direction of the laser irradiator, thereby preventing the debris generated during the grooving process from contaminating the grooved electrode sheet.

[0036] In addition, in the laser grooving equipment for electrode sheets and the electrode sheet grooving method using the laser grooving equipment, the inner surface of the electrode sheet wound around the unwinder faces the grooving roller, whereby the adhesion between the grooving roller and the electrode sheet is excellent, thereby reducing defects such as uncutting. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a cross-sectional view of a laser grooving apparatus for an electrode sheet according to the present invention.

[0038] Figure 2 yes Figure 1 An enlarged perspective view of a slotting roller and a laser irradiator in a laser slotting device for an electrode sheet is shown.

[0039] Figure 3 It shows Figure 1 A perspective view of an electrode sheet facing an unwinder and a slotting drum in a laser slotting apparatus for an electrode sheet is shown.

[0040] Figure 4 4 is a flow chart of the electrode sheet grooving method according to the present invention. DETAILED DESCRIPTION

[0041] Now, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the preferred embodiments of the present invention. However, when describing the operating principles of the preferred embodiments of the present invention in detail, when a detailed description of known functions and configurations incorporated herein may obscure the subject matter of the present invention, the detailed description will be omitted.

[0042] The same reference numerals will be used throughout the drawings to refer to components that perform similar functions or operations. Throughout the specification, when a component is said to be connected to another component, a component may not only be directly connected to another component, but also be indirectly connected to another component via another component. In addition, the inclusion of a certain element does not mean the exclusion of other elements, but means that these elements may be further included unless otherwise specified.

[0043] The description of implementing elements by limitation or addition is applicable to all inventions unless otherwise specifically limited, and does not limit a specific invention.

[0044] In the description and claims of this application, unless otherwise stated, singular forms are intended to include plural forms.

[0045] In the description and claims of this application, unless otherwise stated, "or" includes "and." Therefore, "including A or B" means the case where A is included, the case where B is included, and the case where A and B are included.

[0046] Hereinafter, a laser notching apparatus for an electrode sheet and an electrode sheet notching method using the same according to the present invention will be described with reference to the accompanying drawings.

[0047] Figure 1 is a cross-sectional view of a laser grooving device for an electrode sheet according to the present invention, Figure 2 yes Figure 1 An enlarged perspective view of a slotting roller and a laser irradiator in a laser slotting device for an electrode sheet is shown. Figure 3 It shows Figure 1 A perspective view of an electrode sheet facing an unwinder and a slotting drum in a laser slotting apparatus for an electrode sheet is shown.

[0048] Reference Figures 1 to 3 The laser slotting apparatus for an electrode sheet according to the present invention may include an unwinder 100 , a slotting roller 200 , a laser irradiator 300 , a rewinder 400 , a guide roller 500 , and a fume exhaust box 600 .

[0049] First, the unwinder 100 is wound with the electrode sheet 10 coated with the active material and can be rotated in a direction of unwinding the electrode sheet 10 so that the electrode sheet 10 is transferred to the slotted drum 200. Therefore, the electrode sheet 10 can be divided into a first surface 10a constituting an inner surface and a second surface 10b constituting an outer surface in a state of being wound around the unwinder 100.

[0050] The electrode sheet 10 may be a negative electrode sheet or a positive electrode sheet, and may include a coating portion 11 coated with an active material and an uncoating portion 12 not coated with the active material.

[0051] The negative electrode sheet is manufactured by applying a slurry mixture of a negative electrode active material and a binder to a negative electrode current collector made of copper.

[0052] As the negative electrode active material, for example, carbon such as non-graphitizable carbon or graphite-based carbon; metal composite oxides such as Li x Fe2O3(0≤x≤1), Li xWO2 (0 ≤ x ≤ 1), Sn x Me 1-x Me’ y O z (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, elements of Group 1, 2, 3 of the periodic table, halogens; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8); lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4 or Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials; or Si-based materials such as Si, SiO, SiO2 or mixtures thereof; however, the present invention is not limited thereto.

[0053] The positive electrode sheet is manufactured by coating a slurry mixture of a positive electrode active material and a binder on a positive electrode current collector made of aluminum.

[0054] The positive electrode active material may be composed of, for example, layered compounds such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or compounds substituted with one or more transition metals; lithium manganese oxides represented by the chemical formula Li 1+ x Mn 2-x O4 (where x = 0 to 0.33), or lithium manganese oxides such as LiMnO3, LiMn2O3 or LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5 or Cu2V2O7; Ni-site lithium nickel oxides represented by the chemical formula LiNi 1-x M x O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); lithium manganese composite oxides represented by the chemical formula LiMn 2-x M x O2 (where M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or the chemical formula Li2Mn3MO8 (where M = Fe, Co, Ni, Cu or Zn); LiMn2O4 in which a part of Li in the chemical formula is replaced by alkaline earth metal ions; disulfide compounds; or Fe2(MoO4)3; however, the present invention is not limited thereto.

[0055] In addition, the current collector of the electrode sheet (for example, the negative electrode current collector) may be an electrolytic copper foil, and the opposite surface of the electrode sheet 10 as the electrolytic copper foil is a shiny surface and a matte surface.

[0056] Therefore, the first surface 10a and the second surface 10b of the electrode sheet 10 according to the present invention can have different light reflectivities, and the light reflectivity of the second surface 10b can be lower than that of the first surface 10a. In other words, the first surface 10a can be a shiny surface, and the second surface 10b can be a matte surface.

[0057] Reference numeral 110 denotes a first rotation shaft configured to rotate the unwinder 100 .

[0058] The slotting drum 200 rotated by the second rotation shaft 210 is positioned a predetermined distance apart from the unwinder 100 , is configured to support the slotted electrode sheet 10 , and is disposed to face the first surface 10 a of the electrode sheet 10 .

[0059] The laser irradiator 300 is configured to groove the electrode sheet 10 passing through the grooved roller 200, is disposed to face the second surface 10b that is not opposite to the grooved roller 200, and is located between the unwinder 100 and the grooved roller 200. In other words, the grooved roller 200 is located in front of the laser irradiator 300, and the unwinder 100 is located behind the laser irradiator 300.

[0060] In the groove forming process using the laser irradiator 300, if the laser beam is irradiated toward the first surface 10a, which is a shiny surface with high light reflectivity, the laser beam absorption rate may decrease, thereby causing defects such as uncut parts. Therefore, in the present invention, the laser beam is irradiated toward the second surface 10b of the electrode sheet 10, which is a matte surface with low light reflectivity, thereby preventing the above-mentioned defects.

[0061] In addition, the electrode sheet 10 passes through an active material coating process, a drying process, a winding process, and is transferred and stored in a state of being wound around the unwinder 100 , and thus, the electrode sheet 10 generally has a certain directionality of curvature.

[0062] In other words, in the case where the electrode sheet 10 is wound around the unwinder 100 , the electrode sheet 10 may be deformed such that the first surface 10 a is slightly concave, and the second surface 10 b is slightly convex.

[0063] Therefore, the surface of the electrode sheet 10 facing the unwinder 100 and the surface of the electrode sheet facing the slotting roller 200 are preferably the same surface, that is, the first surface 10a. This is because if the surface of the electrode sheet 10 facing the slotting roller 200 is different from the surface of the electrode sheet facing the unwinder 100, the slotting roller 200 and the electrode sheet 10 may not be properly in close contact due to the difference in curvature directionality, which may result in poor slot size, joint folding, etc.

[0064] The rewinder 400 is configured to wind the slotted electrode sheet 10 , and a known driving device (not shown) such as a motor configured to rotate the third rotating shaft 410 is connected to the rewinder.

[0065] The rewinder 400 is positioned to be spaced a predetermined distance from the slotting drum 200. More specifically, the rewinder is preferably located at a lower position than the slotting drum 200, and more preferably located further back than the rewinder 400. This is because it is possible to prevent the slotted electrode sheet from being contaminated by falling or scattering of debris generated during the slotting process using the laser irradiator 300.

[0066] Of course, a smoke exhaust box 600 for removing debris generated during grooving can be set between the electrode sheet 10 and the laser irradiator 300 or near the electrode sheet 10 and the laser irradiator 300, but it is difficult to completely remove the generated debris only by the smoke exhaust box 600, so the rewinder 400 is preferably located below and behind the grooving drum 200.

[0067] Next, the guide roller 500 configured to change the moving direction D of the supplied electrode sheet 10 will be described. The guide roller 500 may include a first guide roller 510 , a second guide roller 520 , and a third guide roller 530 .

[0068] The first guide roller 510 and the second guide roller 520 may be located between the unwinder 100 and the slotting drum 200 , wherein the first guide roller 510 may be located closer to the unwinder 100 and the second guide roller 520 may be located closer to the slotting drum 200 .

[0069] The first guide roller 510 and the second guide roller 520 may be located at a higher position than the unwinder 100 and the slotted drum 200, and may change the moving direction D of the electrode sheet 10 moving toward the slotted drum 200. Specifically, the electrode sheet 10 may move upward to the first guide roller 510, may move horizontally from the first guide roller 510 to the second guide roller 520, and may move downward from the second guide roller 520 to the slotted drum 200.

[0070] At this time, the first guide roller 510 and the second guide roller 520 may be disposed to face the second surface 10b of the electrode sheet 10. Thus, the electrode sheet 10 wound around the unwinder 100 passes through the first guide roller 510 and the second guide roller 520 in a state where the first surface is convex.

[0071] The third guide roller 530 is configured to change the moving direction D of the slotted electrode sheet 10 so that the slotted electrode sheet can be transferred to the rewinder 400. That is, the third guide roller 530 is preferably located below the slotted drum 200 so that the slotted electrode sheet 10 can be transferred to the rewinder 400 located below and behind the slotted drum 200. In this case, the third guide roller 530 and the rewinder 400 face the first surface 10a of the slotted electrode sheet 10.

[0072] In addition, the first guide roller 510 and the third guide roller 530 perform a function of changing the moving direction D of the electrode sheet 10 and guiding a portion of the electrode sheet 10 to be grooved so as to be in close contact with the groove drum 200 .

[0073] Reference numeral 511 denotes a fourth rotation axis for rotation of the first guide roller 510 , reference numeral 521 denotes a fifth rotation axis for rotation of the second guide roller 520 , and reference numeral 531 denotes a sixth rotation axis for rotation of the third guide roller 530 .

[0074] Next, a method of laser grooving an electrode sheet using the laser grooving apparatus for the electrode sheet will be described. Figure 4 4 is a flow chart of the electrode sheet grooving method according to the present invention.

[0075] Reference Figures 1 to 4 , the laser grooving method for an electrode sheet according to the present invention includes the following steps: a first step of supplying the electrode sheet 10 wound around the unwinder 100 to the grooving roller 200; a second step of irradiating a laser beam toward the electrode sheet 10 in contact with the grooving roller 200 to groove the electrode sheet 10; and a third step of winding the grooved electrode sheet 10.

[0076] First, the first step is a step of supplying the electrode sheet 10 wound around the unwinder 10 to the slotted drum 200 via at least one guide roller 500. More specifically, the electrode sheet 10 wound around the unwinder 10 is supplied to the slotted drum 200 through a first moving direction changing step using the first guide roller 510 and / or the second guide roller 520.

[0077] The electrode sheet 10 wound around the unwinder 100 includes a first surface 10a constituting an inner surface and a second surface 10b constituting an outer surface, wherein the electrode sheet 10 moves in a state where the first guide roller 510 and the second guide roller 520 face the second surface 10b of the electrode sheet 10 and the grooved roller 200 faces the first surface 10a of the electrode sheet 10.

[0078] The second step is to form an electrode tab by removing a portion of the uncoated portion 12 of the electrode sheet 10 by groove formation, wherein the laser irradiator 300 irradiates a laser beam toward the second surface 10b of the electrode sheet 10, which has a relatively low light reflectivity. Since the laser beam is irradiated toward the second surface 10b, which has a high laser beam absorptivity, the processability of the electrode sheet is improved.

[0079] The slotted electrode sheet 10 is moved backward by the second moving direction changing step using the third guide roller 530. At this time, the third guide roller 530 is located below the slotting drum 200 and rotates while facing the first surface 10a of the electrode sheet 10.

[0080] The third step is to rewind the slotted electrode sheet 10 using the rewinder 400 , and the electrode sheet 10 is wound with the first surface 10 a facing the rewinder 400 .

[0081] Those skilled in the art to which the present invention pertains will appreciate that, based on the above description, various applications and modifications are possible within the scope of the present invention.

[0082] (Explanation of Reference Numerals)

[0083] 10: Electrode sheet

[0084] 10a: First surface 10b: Second surface

[0085] 11: Coated part 12: Uncoated part

[0086] 100: Unwinder

[0087] 110: First rotation axis

[0088] 200: slotted drum

[0089] 210: Second rotation axis

[0090] 300: Laser irradiator

[0091] 400: Rewinder

[0092] 410: Third rotation axis

[0093] 500: Guide roller

[0094] 510: First guide roller 511: Fourth rotation axis

[0095] 520: Second guide roller 521: Fifth rotation axis

[0096] 530: Third guide roller 531: Sixth rotation axis

[0097] 600: Smoke exhaust box

[0098] D: Moving direction

Claims

1. A laser grooving device for an electrode sheet, the laser grooving device comprising: an unwinder, around which an electrode sheet is wound; a slotted roller positioned to be spaced apart from the unwinder by a predetermined distance, the slotted roller being configured to support the supplied electrode sheet; a laser irradiator configured to groove the electrode sheet; as well as a rewinder positioned a predetermined distance away from the slotted drum, the rewinder being configured to wind the slotted electrode sheet, wherein The electrode sheet wound around the unwinder includes a first surface constituting an inner surface and a second surface constituting an outer surface, and The grooved roller is disposed to face the first surface of the electrode sheet.

2. The laser slotting equipment according to claim 1, wherein: The first surface and the second surface of the electrode sheet have different light reflectivities, and The light reflectivity of the second surface is lower than the light reflectivity of the first surface.

3. The laser slotting equipment according to claim 1, wherein: The laser irradiator is located between the unwinder and the slotting drum.

4. The laser slotting device according to claim 1, further comprising: a guide roller configured to change a moving direction of the supplied electrode sheet, wherein The guide rollers include a first guide roller and a second guide roller located between the unwinder and the slotted drum.

5. The laser slotting equipment according to claim 4, wherein: The first guide roller and the second guide roller are located at a higher position than the unwinder and the slotting drum.

6. The laser slotting equipment according to claim 5, wherein: The first guide roller and the second guide roller face the second surface of the electrode sheet.

7. The laser slotting equipment according to claim 4, wherein: The guide rollers include a third guide roller located below the grooved drum.

8. The laser slotting equipment according to claim 7, wherein: The rewinder is located behind the third guide roller.

9. The laser slotting equipment according to claim 8, wherein: The third guide roller faces the first surface of the electrode sheet.

10. A laser grooving method for an electrode sheet, the laser grooving method comprising the following steps: In a first step, the electrode sheet wound around the unwinder is supplied to a slotted drum; The second step is to irradiate a laser beam toward the electrode sheet in contact with the slotting roller to slot the electrode sheet; as well as The third step is to wind the slotted electrode sheet, wherein: The electrode sheet wound around the unwinder includes a first surface constituting an inner surface and a second surface constituting an outer surface, and The grooved roller faces the first surface of the electrode sheet.

11. The laser grooving method according to claim 10, wherein: In the second step, the laser beam is irradiated toward the second surface of the electrode sheet, and The first surface and the second surface of the electrode sheet have different light reflectivities, and the light reflectivity of the second surface is lower than that of the first surface.

12. The laser grooving method according to claim 10, wherein: A first moving direction changing step is further included between the first step and the second step, wherein the moving direction of the supplied electrode sheet is changed, The first moving direction changing step is performed by a first guide roller and a second guide roller located between the unwinder and the slotted drum, and The first guide roller and the second guide roller rotate so as to face the second surface of the electrode sheet.

13. The laser grooving method according to claim 10, wherein: A second moving direction changing step is further included between the second step and the third step, wherein the moving direction of the slotted electrode sheet is changed. The second moving direction changing step is performed by a third guide roller located behind the grooved drum, and The third guide roller rotates so as to face the first surface of the electrode sheet.

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