Electrode running roller and notching device including the same

Abstract

The present invention provides an electrode running roller for running an electrode sheet in which an electrode active material is coated on a current collector, the roller comprising: The running roller includes a cylindrical section; and a tapered section extending from one side end of the cylindrical section; The tapered section relates to an electrode running roller having an outer diameter that gradually decreases toward the end of the tapered section.

Description

[Technical field]

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2021-0115349 filed on August 31, 2021, and Korean Patent Application No. 10-2022-0109300 filed on August 30, 2022, and incorporates all contents disclosed in the documents of said Korean patent applications as part of this specification.

[0002] The present invention relates to an electrode running roller and a notching device including the same. [Background technology]

[0003] As technological development and demand for mobile devices increases, rechargeable secondary batteries are widely used as energy sources for various mobile devices. Secondary batteries are also attracting attention as energy sources for electric vehicles and hybrid vehicles, which have been proposed as a solution to address air pollution caused by existing gasoline and diesel vehicles.

[0004] Secondary batteries are classified into coin type batteries, cylindrical type batteries, square type batteries, and pouch type batteries depending on the shape of the battery case that the electrode assembly is built into. Generally, the electrode assembly built into the battery case is classified into a jelly roll type in which a separator is interposed between the positive and negative electrodes and the battery is wound up, a stack type in which a plurality of unit cells are stacked and each unit cell has a separator interposed between the positive and negative electrodes, and a stack / folding type in which the unit cells are wound up with a separator film.

[0005] Such a secondary battery can be manufactured by coating an electrode mixture, which is a mixture of an electrode active material, a conductive agent, a binder, etc., on an electrode collector, drying the mixture to manufacture an electrode, stacking the manufactured electrode together with a separator to manufacture an electrode assembly, and then incorporating and sealing the electrode assembly together with an electrolyte in a battery case. The electrode assembly can be classified into a stack type, a folding type, a stack-folding type, etc., depending on the manufacturing method. In the case of a stack type or stack-folding type electrode assembly, a unit assembly has a structure in which a positive electrode and a negative electrode are sequentially stacked with a separator sandwiched therebetween. To manufacture such an electrode assembly, it is necessary to first manufacture a positive electrode and a negative electrode having electrode tabs formed thereon.

[0006] That is, in order to manufacture a unit electrode having an electrode tab formed thereon, a notching process is first required to form electrode tabs on a continuous electrode sheet having an electrode active material applied on one or both sides. The notching process generally involves placing the electrode sheet on a die and punching out parts of the electrode sheet using a press. Here, the electrode sheet is transported by a traveling roller that travels in synchronization with the operation of the press, and is sequentially punched out to form the electrode tabs.

[0007] The surface of the electrode sheet is composed of a coated portion coated with an active material and a non-coated portion not coated with an active material, and the running roller is cylindrical. The electrode sheet moves in close contact with the outer circumferential surface of the running roller, and when the electrode sheet runs on the running roller, the coated portion and the non-coated portion of the electrode sheet surface have different friction coefficients, resulting in a difference in tension with the roller. This can lead to problems such as the non-coated portion breaking or breakage occurring at the boundary between the coated portion and the non-coated portion.

[0008] Therefore, there is a strong need for a technique that can solve the above problems. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Korean Patent No. 10-1759570 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide an electrode traveling roller that can solve the problem of breakage occurring at the boundary between the coated and uncoated portions of an electrode sheet when the electrode sheet is transported by a traveling roller.

[0011] Another object of the present invention is to provide a notching device including the traveling roller. [Means for solving the problem]

[0012] In order to achieve the above objective, The present invention provides an electrode running roller for running an electrode sheet having a current collector coated with an electrode active material, The running roller includes a cylindrical section; and a tapered section extending from one end of the cylindrical section; The tapered section provides an electrode running roller having an outer diameter that gradually decreases toward the end of the tapered section.

[0013] In one embodiment of the present invention, the ratio of the length of the cylindrical section to the length of the tapered section may be 4:1 to 1:1.

[0014] In one embodiment of the present invention, the tapered section may be in the form of a truncated cone.

[0015] In one embodiment of the present invention, the tapered section may form an outer circumferential surface that is inclined at an angle of 0.2 to 0.5 toward the central axis based on the outer circumferential surface of the cylindrical section.

[0016] In one embodiment of the present invention, the electrode sheet includes a coated portion coated with an electrode active material and an uncoated portion not coated with an electrode active material, The electrode running roller may be disposed so that the uncoated portion is located in a tapered section.

[0017] In one embodiment of the present invention, the electrode running roller may be disposed such that a landed portion of the electrode sheet is located at a boundary between a cylindrical section and a tapered section.

[0018] In an embodiment of the present invention, the electrode sheet may be in contact with an outer circumferential surface of the cylindrical section except for an uncoated portion.

[0019] The present invention also provides a notching device for forming an electrode tab on a continuous electrode sheet in which an electrode active material is coated on one or both sides of a current collector in a battery cell production process, comprising: a press for punching the electrode sheet such that an electrode tab is formed in a portion of the electrode sheet; A die having an opening having a shape corresponding to the press through which scrap punched by the press is discharged; and There is provided a notching device including the electrode running roller of the present invention, which transfers an electrode sheet to the press in synchronization with the operation of the press. Effect of the Invention

[0020] The electrode running roller of the present invention includes a tapered section extending to one end of the cylindrical section, and an uncoated portion of the electrode sheet is disposed in the tapered section, thereby reducing breakage that occurs at the boundary between the coated portion and the uncoated portion of the electrode sheet during electrode running. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a perspective view showing an electrode running roller according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of an electrode sheet. [Diagram 3] FIG. 11 is a perspective view showing a conventional electrode running roller. [Figure 4]FIG. 2 is a perspective view illustrating an example of an electrode running roller according to an embodiment of the present invention when applied; [Diagram 5] FIG. 2 is a front view showing a notching device including an electrode running roller according to an embodiment of the present invention. [Figure 6] 1 is a graph showing the results of measuring the maximum effective stress of the electrode traveling rollers of Examples 1 to 4 and Comparative Examples 1 to 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in order to enable those skilled in the art to easily carry out the present invention. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0023] In order to clearly explain the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used to refer to the same or similar components throughout the specification.

[0024] Furthermore, the terms and words used in this specification and the claims should not be interpreted limited to their ordinary and dictionary meanings, but should be interpreted in a way that is consistent with the technical ideas of the present invention, based on the principle that the inventor himself / herself can appropriately define the concept of a term in order to explain the invention in the best possible manner.

[0025] FIG. 1 is a perspective view showing an electrode running roller according to one embodiment of the present invention.

[0026] 1, an electrode traveling roller 100 according to an embodiment of the present invention is an electrode traveling roller 100 that travels an electrode sheet 10 having an electrode active material coated on a current collector 11, and the traveling roller 100 includes a cylindrical section 110 and a tapered section 120 extending from one end of the cylindrical section 110. The tapered section 120 has an outer diameter that gradually decreases toward an end of the tapered section 120.

[0027] Referring to FIG. 2, the electrode sheet 10 may include a coated portion 12 coated with an electrode active material on one or both sides of a current collector 11, and an uncoated portion 13 not coated with an electrode active material.

[0028] Specifically, the coated portion 12 of the electrode sheet 10 may be continuously coated with an electrode active material along the running direction of the electrode running roller 100. Also, the uncoated portion 13 may be a portion on a side in the running direction of the electrode running roller 100 that is not coated with an electrode active material.

[0029] In addition, in the electrode traveling roller 100 , the plain portion 13 of the electrode sheet 10 may be disposed to be located in the tapered section 120 of the traveling roller 100 .

[0030] FIG. 3 is a perspective view showing an electrode running roller according to one conventional embodiment.

[0031] Referring to FIG. 3, a conventional electrode running roller 100 includes a cylindrical section 110 and a variable section 130 having a diameter smaller than that of the cylindrical section 110 such that a step S1 is formed on the outer circumferential surface of the cylindrical section.

[0032] At this time, the coated portion 12 of the electrode sheet 10 may be disposed at a position contacting the outer circumferential surface of the cylindrical section 110, and the uncoated portion 13 may be disposed to be located in the variable section 130 of the traveling roller 100. In addition, the boundary surface between the coated portion 12 and the uncoated portion 13 may be in contact with the outer circumferential surface of the cylindrical section 110. Therefore, when the electrode traveling roller 100 travels, the cylindrical section 110 directly contacts the boundary surface between the coated portion 12 and the uncoated portion 13 and acts as an external force, so that the effect of blocking and dispersing stress is negligible. As a result, there is a problem that the electrode sheet 10 may break when the electrode sheet 10 is transported by the traveling roller 100.

[0033] Therefore, the present invention provides an electrode running roller 100 including a tapered section 120 extending from one end of a cylindrical section 110 to solve the above problems.

[0034] Hereinafter, with reference to FIG. 1, an electrode running roller 100 according to one embodiment of the present invention will be described in more detail.

[0035] In one embodiment of the present invention, the ratio of the length C of the cylindrical section to the length L of the tapered section may be 4:1 to 1:1, and preferably 3:2 to 7:3. In this ratio range, the stress generated at the boundary between the coated portion 12 and the uncoated portion 13 of the electrode sheet 10 can be reduced, and the occurrence of breakage of the electrode sheet 10 can be improved. Specifically, when the maximum effective stress generated at the boundary between the coated portion 12 and the uncoated portion 13 of the electrode sheet 10 is 50 MPa or more, the electrode sheet 10 may break. However, when the ratio of the length C of the cylindrical section to the length L of the tapered section is 4:1 to 1:1, the maximum effective stress generated at the boundary between the coated portion 12 and the uncoated portion 13 of the electrode sheet 10 is less than 50 MPa, and therefore, the problem of breakage of the electrode sheet 10 can be improved. If the ratio of the length (C) of the cylindrical section to the length (L) of the tapered section is outside the range of 4:1 to 1:1, the effect of improving the breakage problem generated in the electrode sheet 10 due to stress generated at 50 MPa or more is low.

[0036] Also, in one embodiment of the present invention, the tapered section 120 may have a truncated cone shape, and may form an outer circumferential surface that is inclined at an angle of 0.2 to 0.5, preferably an angle of 0.25 to 0.35, toward the central axis P based on the outer circumferential surface of the cylindrical section 110. Within this angle range, contact between the uncoated portion 13 of the electrode sheet 10 and the tapered section 120 can be minimized, and the occurrence of breakage of the electrode sheet 10 can be improved.

[0037] FIG. 4 is a perspective view illustrating an example of an electrode traveling roller according to an embodiment of the present invention.

[0038] 4, the electrode traveling roller 100 according to an embodiment of the present invention is disposed such that the uncoated portion 13 of the electrode sheet 10 is located in the tapered section 120, and the electrode traveling roller 100 may have the coated portion 12 of the electrode sheet 10 disposed at the boundary between the cylindrical section 110 and the tapered section 120. In addition, the electrode sheet 10 may be in contact with the outer circumferential surface of the cylindrical section 110 except for the uncoated portion 13.

[0039] Therefore, the electrode running roller 100 according to one embodiment of the present invention configured as described above forms a tapered section 120 at one end of the cylindrical section 110 to which the electrode sheet 10 adheres to the outer circumferential surface when the electrode sheet 10 runs, and the part of the electrode sheet 10 except for the uncoated section 13 where the electrode active material is not coated can adhere to the outer circumferential surface of the cylindrical section 110, thereby preventing breakage that occurs at the boundary between the uncoated section 13 and the coated section 12.

[0040] A notching device according to an embodiment of the present invention will be described below.

[0041] FIG. 5 is a front view showing a notching device including an electrode running roller according to an embodiment of the present invention.

[0042] Referring to FIG. 5, a notching device 200 according to an embodiment of the present invention includes an electrode running roller 100 for running an electrode sheet 10 .

[0043] More specifically, the notching device 200 according to an embodiment of the present invention includes a press 210, a die 220, and an electrode running roller 100, and a continuous electrode sheet 10 having an electrode active material applied on one or both sides of a current collector runs on the electrode running roller 100 of the notching device 200.

[0044] The press 210 punches the electrode sheet 10 at regular intervals so that electrode tabs are formed on the electrode sheet 10 , and the electrode transport roller 100 transports the electrode sheet 10 to the press 210 in synchronization with the operation of the press 210 .

[0045] Further, the die 220 is formed with an opening 221 having a shape corresponding to the press 210 so that the scrap punched out by the press 210 can be discharged.

[0046] The electrode running roller 100 is according to the above-described embodiment of the present invention. EXAMPLES

[0047] Below, preferred examples are presented to aid in understanding the present invention. However, the following examples are merely illustrative of the present invention, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and technical spirit of the present invention. Naturally, such changes and modifications also fall within the scope of the appended claims.

[0048] Examples 1 to 4 and Comparative Examples 1 to 3. Manufacture of electrode running rollers Electrode running rollers of Examples 1 to 4 and Comparative Examples 2 and 3 having the ratios of the length C of the cylindrical section and the length L of the tapered section as shown in Table 1 below were manufactured.

[0049] Also, an electrode running roller of Comparative Example 1 was manufactured that included a variable section instead of the tapered section.

[0050] [Table 1]

[0051] Experimental example 1. Measurement of maximum effective stress of electrode running roller When the electrode sheet was run using the electrode running rollers of Examples 1 to 4 and Comparative Examples 1 to 3, the maximum effective stress generated at the boundary surface between the uncoated portion and the coated portion of the electrode sheet was measured.

[0052] The maximum effective stress was measured using a flexible multi-body dynamics technique, which is a virtual verification model, and the measurement results are shown in Table 2 below.

[0053] [Table 2]

[0054] If the maximum effective stress is 50 MPa or more, the electrode sheet may break.

[0055] From the results in Table 2, the electrode running rollers of Examples 1 to 4, which include a tapered section extending from one end of the cylindrical section, exhibited a maximum effective stress of less than 50 MPa. This shows that the electrode running roller of the present invention can prevent breakage of the electrode sheet and stably transport the electrode sheet.

[0056] In addition, Example 1, in which the ratio of the length of the cylindrical section to the length of the tapered section was 7:3, and Example 3, in which the ratio was 3:2, showed a lower maximum effective stress than Example 2, in which the ratio of the length of the cylindrical section to the length of the tapered section was 1:1, and Example 4, in which the ratio was 4:1. From the above results, it can also be seen that a ratio of the length of the cylindrical section to the length of the tapered section of 3:2 to 7:3 is more preferable in terms of preventing breakage of the electrode sheet.

[0057] Comparative Example 1 is an electrode running roller that includes a variable section instead of a tapered section at one end of the cylindrical section, and the maximum effective stress was 50 MPa or more due to the step between the cylindrical section and the tapered section. Therefore, it can be predicted that the electrode running roller of Comparative Example 1 cannot prevent breakage during transport of the electrode sheet.

[0058] In addition, Comparative Examples 2 and 3, in which the ratio of the length of the cylindrical section to the length of the tapered section did not fall within the range of 4:1 to 1:1, showed a lower maximum effective stress than Comparative Example 1 in which a step was formed, but still showed a result of 50 MPa or more. From the above results, it can be seen that only when the ratio of the length of the cylindrical section to the length of the tapered section was 4:1 to 1:1, the maximum effective stress was less than 50 MPa, and therefore it was possible to prevent breakage that may occur in the electrode sheet. [Explanation of symbols]

[0059] 10: Electrode sheet 11: Current collector 12:Landed area 13: Plain section 100: Electrode running roller 110: Cylindrical section 120: Tapered section 130: Variable section 200: Notching device 210: Press 220: Die 221:Aperture

Claims

1. An electrode running roller for running an electrode sheet having a current collector coated with an electrode active material, The electrode running roller includes a cylindrical section; and a tapered section extending from one end of the cylindrical section; The tapered section has an outer diameter that gradually decreases toward a distal end of the tapered section, the ratio of the length of the cylindrical section to the length of the tapered section is between 4:1 and 1:1; The electrode sheet includes a coated portion coated with an electrode active material and an uncoated portion not coated with the electrode active material, The electrode running roller is disposed so that the uncoated portion is located in the tapered section, the electrode running roller is disposed so that a landed portion of the electrode sheet is located at a boundary between the cylindrical section and the tapered section. Electrode running roller.

2. The electrode running roller according to claim 1 , wherein the tapered section has a truncated cone shape.

3. The electrode running roller according to claim 1, wherein the tapered section forms an outer peripheral surface inclined at an angle of 0.2 to 0.5 toward a central axis based on the outer peripheral surface of the cylindrical section.

4. The electrode running roller according to claim 1 , wherein a portion of the electrode sheet other than the uncoated portion contacts an outer circumferential surface of the cylindrical section.

5. A notching device for forming an electrode tab on a continuous electrode sheet in which an electrode active material is coated on one or both sides of a current collector in a battery cell production process, comprising: a press for punching the electrode sheet so that the electrode tab is formed in a portion of the electrode sheet; A die having an opening having a shape corresponding to the press through which scrap punched by the press is discharged; and A notching device comprising the electrode running roller according to any one of claims 1 to 4, which transfers an electrode sheet to the press in synchronization with the operation of the press.

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