Electrode sheet cutting device including upper cutter and lower cutter and electrode sheet cutting method using the same

Abstract

The present invention relates to an electrode sheet cutting device and an electrode sheet cutting method using the same, which are capable of preventing deformation of the electrode sheet and reducing the generation of foreign matter by placing upper and lower cutters that apply the same force at the same speed on both sides of the electrode sheet and cutting it from one side to the other.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 2020-0060561, filed on May 20, 2020, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to an electrode sheet cutting device including an upper cutter and a lower cutter, and an electrode sheet cutting method using the same, and more particularly to an electrode sheet cutting device and an electrode sheet cutting method using the same, which prevent deformation of the cut surface or residue of burrs on the cut surface of the electrode sheet when cutting the electrode sheet. [Background technology]

[0003] A secondary battery generally includes a positive electrode, a negative electrode, and a separator, each of which is made of a current collector coated with an active material on one or both sides. Here, electrodes such as a positive electrode and a negative electrode are formed in the form of an electrode sheet coated with an electrode active material on one or both sides, and then cut into a shape.

[0004] FIG. 1 is a schematic diagram of an electrode sheet cutting device and cutting method according to the prior art, and FIG. 2 is an enlarged view of a cut surface of an electrode sheet cut by the electrode sheet cutting device according to the prior art.

[0005] As shown in Fig. 1, the conventional electrode sheet cutting device cuts an electrode sheet 10 by placing the electrode sheet 10 on an electrode sheet support table 20 having a groove in the portion where the cut surface of the electrode sheet is located (i) and then cutting the electrode sheet 10 with a cutter 30 (ii). Here, the cutter 30 applies force to the groove in the electrode sheet support table 20 to cut the electrode sheet 10. Here, if there is no groove on the electrode sheet support table 20, the cutter 30 applies force to the cut surface of the electrode sheet 10 to cut the electrode sheet 10.

[0006] However, when the electrode sheet 10 is cut by the conventional electrode sheet cutting device as shown in FIG. 2, the cut surface 11 of the electrode is deformed or residues such as burrs are present on the cut surface 11 of the electrode.

[0007] 2, if a portion of the electrode sheet 10 is deformed or if there are remnants such as burrs, the deformed portion or remnants may hinder the transfer of the electrode sheet 10, and when an electrode assembly is formed, the deformed portion or remnants may reduce the density of the electrode assembly, resulting in a problem of reduced battery capacity. In addition, when a pouch-type secondary battery is formed using the electrodes, the electrodes may not be stacked stably, and therefore the desired shape may not be formed.

[0008] In the drawings of Patent Document 1, cutters for cutting the electrode plates are positioned on both sides of the object, but since the cut is made from the center, no consideration is given to removal of residues or deformation of the cut surface of the electrode sheet.

[0009] Therefore, there is a need for an electrode sheet cutting device and an electrode sheet cutting method using the same that can minimize deformation of the electrode sheet and minimize residues caused by cutting the electrodes when cutting the electrode sheet. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Korean Patent Publication No. 2010-0096018 Summary of the Invention [Problem to be solved by the invention]

[0011] In order to solve the above problems, an object of the present invention is to provide an electrode sheet cutting device capable of minimizing deformation of an electrode sheet and an electrode sheet cutting method using the same.

[0012] Another object of the present invention is to provide a method for cutting an electrode sheet, which can limit the cutting position and order of the electrode sheet, thereby minimizing deformation and residue of the electrode sheet caused by cutting the electrode sheet. [Means for solving the problem]

[0013] In order to solve the above problems, the electrode sheet cutting device according to the present invention includes an upper cutter located above the electrode sheet and cutting the electrode sheet, a lower cutter located corresponding to the upper cutter and contacting the upper cutter to cut the electrode sheet, and an electrode sheet support table located between the upper cutter and the lower cutter, supporting the electrode sheet, and having a through hole corresponding to a cutting portion where the electrode sheet is cut by contacting the upper cutter and the lower cutter.

[0014] In addition, the upper cutter and the lower cutter can apply the same force to the electrode sheet.

[0015] Also, the upper cutter and the lower cutter may move to the electrode sheet at the same speed.

[0016] In addition, the upper cutter and the lower cutter may cut the electrode sheet while expanding a cutting range from one side of the cutting portion.

[0017] In addition, the cut portion may widen from a portion adjacent to a center portion of the electrode sheet toward an outer periphery thereof.

[0018] The upper cutter and the lower cutter may have the same shape or a symmetric shape.

[0019] Before cutting the electrode sheet, a distance between the upper cutter and the lower cutter may be greater toward one side.

[0020] The electrode sheet may be cut to form electrode tab protrusions.

[0021] Here, the upper cutter and the lower cutter may start cutting from a position where the electrode tab protrusion is to be formed.

[0022] The present invention also provides a method for cutting an electrode sheet, comprising the steps of: (S1) preparing an electrode sheet on an electrode sheet support table having a through hole formed in a portion of the electrode sheet to be cut; and (S2) cutting the electrode sheet using an upper cutter and a lower cutter.

[0023] In step (S2), the electrode sheet may be cut in a longitudinal direction or a direction perpendicular thereto to form a single electrode assembly, or may be cut into a concave-convex shape to form an electrode tab.

[0024] When the electrode tab is formed in step (S2), the upper cutter and the lower cutter may first cut the protruding portion of the electrode tab and then cut the farthest point from the protruding portion of the electrode tab.

[0025] The point furthest from the electrode tab protrusion may be another cut portion of the electrode sheet.

[0026] The present invention can select and combine one or more of the above-mentioned configurations that are not contradictory to each other. [Brief description of the drawings]

[0027] [Figure 1] 1A and 1B are schematic diagrams of an electrode sheet cutting device and cutting method according to the prior art. [Diagram 2] 1 is an enlarged view of a cut surface of an electrode cut by an electrode sheet cutting device according to the prior art; [Diagram 3] 1 is a schematic diagram of an electrode sheet cutting device and a cutting method according to the present invention. [Figure 4] 2 is a schematic diagram of an upper cutter and a lower cutter of the electrode sheet cutting device according to the first embodiment of the present invention. FIG. [Diagram 5] 6A to 6C are schematic diagrams showing other shapes of the upper cutter and the lower cutter of the electrode sheet cutting device according to the first embodiment. [Figure 6] 10 is a schematic diagram of an upper cutter and a lower cutter of an electrode sheet cutting device according to a second embodiment of the present invention. FIG. [Figure 7] FIG. 2 is a schematic diagram showing an upper portion of an electrode sheet support base according to the present invention. [Figure 8] 4 is an enlarged view of a cut surface of an electrode cut by the electrode sheet cutting device according to the present invention. FIG. [Figure 9] 1 is a schematic diagram of an electrode sheet cutting device according to the present invention and an electrode sheet cut by the device; [Figure 10] 11A and 11B are diagrams showing the results of a virtual simulation of the force applied to the electrode sheet by the electrode sheet cutting device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] In this application, the terms "comprise", "have", "include" and the like are intended to specify the presence of features, numbers, steps, components, parts or combinations thereof described in the specification, but should be understood as not precluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0029] In addition, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only the case where the part is directly connected to another part, but also the case where the part is indirectly connected via another element between the two parts. In addition, when a part includes a certain component, it does not mean that the other component is excluded, but that the part may further include the other component, unless otherwise specified.

[0030] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electrode sheet cutting device and an electrode sheet cutting method using the same according to the present invention will be described in detail with reference to the accompanying drawings.

[0031] FIG. 3 is a schematic diagram of an electrode sheet cutting device and cutting method according to the present invention.

[0032] The electrode sheet cutting device according to the present invention includes an electrode sheet support table 200 capable of supporting an electrode sheet 100, an upper cutter 300 located on the upper part of the electrode sheet 100, and a lower cutter 400 located below the electrode sheet support table 200 and in a position in contact with the upper cutter 300.

[0033] Here, in order for the upper cutter 300 and the lower cutter 400 to contact each other while cutting the electrode sheet 100, the electrode sheet support 200 may have a through hole 210 at a cutting portion where the upper cutter 300 and the lower cutter 400 contact each other to cut the electrode sheet 100.

[0034] The upper cutter 300 is connected to an upper pressure unit 310, and the lower cutter 400 is connected to a lower pressure unit 410 to move with a constant force and speed. The upper cutter 300 applies an upper pressure force F1 to the upper part of the electrode sheet 100, and the lower cutter 400 applies a lower pressure force F2 to the lower part of the electrode sheet 100. The lower cutter 400 cuts the electrode sheet 100 through the through-holes 210 and comes into contact with the upper cutter 300.

[0035] The upper pressure force F1 and the lower pressure force F2 may be the same to prevent deformation of the electrode sheet 100. When the forces applied to the electrode sheet 100 by the upper cutter 300 and the lower cutter 400 are the same, the risk of the electrode sheet 100 being deformed upward or downward is reduced.

[0036] In addition, the upper cutter 300 and the lower cutter 400 can arrive at the same speed while being spaced the same distance from the electrode sheet 100. Therefore, the upper cutter 300 or the lower cutter 400 can be prevented from arriving at the electrode sheet 100 first and cutting it, thereby suppressing deformation of the electrode sheet 100.

[0037] FIG. 4 is a schematic diagram of an upper cutter and a lower cutter of the electrode sheet cutting device according to the first embodiment of the present invention, and FIG. 5 is a schematic diagram showing other shapes of the upper cutter and the lower cutter of the electrode sheet cutting device according to the first embodiment.

[0038] In the electrode sheet cutting device according to the first embodiment of the present invention, the upper cutter 300 and the lower cutter 400 may have the same shape. When viewed from the side, the upper cutter 300 and the lower cutter 400 may be a rectangular parallelepiped or parallelogram as shown in Fig. 4, or may be a right-angled triangle in which one side of the upper cutter 300 and the lower cutter 400 protrudes from the other side as shown in Fig. 5, and is not limited to this shape as long as the electrode sheet 100 can be cut evenly.

[0039] Before cutting the electrode sheet 100, the distance B between the upper cutter 300 and the lower cutter 400 may gradually increase from one side end to the other side end as shown in Fig. 4. That is, the distance at which the upper cutter 300 and the lower cutter 400 first come into contact with each other is very small, and the distance B between the cutters may be arranged to increase as they move toward the cutting direction A.

[0040] The upper cutter 300 and the lower cutter 400 arranged as described above may cut the electrode sheet 100 while expanding the cutting range from one side of the cutting part. That is, the upper cutter 300 and the lower cutter 400 may operate in a push-cutting manner. Thus, the upper cutter 300 and the lower cutter 400 may have different movement ranges at one end of the cutting part and the other end of the cutting part.

[0041] In this way, when the electrode sheet cutting device according to the present invention cuts the electrode sheet while expanding the range from one side of the cutting portion to the other side, the force applied to the electrode sheet is increased, cutting becomes easier, and deformation of the electrode sheet is reduced. Also, since the electrode sheet is cut while expanding the range from one side to the other side, foreign objects caused by cutting are also moved to the other side.

[0042] Here, in order to easily remove foreign matter, it is preferable that the cutting portion widens from the portion close to the center of the electrode sheet 100 to the outer periphery, i.e., the upper cutter 300 and the lower cutter 400 first come into contact with each other at the center of the electrode sheet 100, and then the cutting portion is increased toward the outer periphery of the electrode sheet 100.

[0043] After cutting the electrode sheet by operating in a push-cutting manner as described above, in the electrode sheet cutting device of the present invention, the distance B between the cutters decreases until the entire surfaces of the upper cutter 300 and the lower cutter 400 come into contact with each other as shown in Fig. 4. Then, after the entire surfaces of the upper cutter 300 and the lower cutter 400 come into contact with each other to cut the cutting portion, the upper cutter 300 and the lower cutter 400 move away from the electrode sheet 100, respectively.

[0044] That is, the electrode sheet cutting method according to the present invention can be broadly divided into the steps of: (S1) preparing the electrode sheet 100 on an electrode sheet support 200 having a through hole 210 in a portion where the electrode sheet 100 is to be cut; and (S2) cutting the electrode sheet 100 using the upper cutter 300 and the lower cutter 400. After the electrode sheet 100 is completely cut in the step (S2), the method can further include a step of removing the upper cutter 300 and the lower cutter 400 from the electrode sheet 100.

[0045] FIG. 6 is a schematic diagram of an upper cutter and a lower cutter of an electrode sheet cutting device according to a second embodiment of the present invention.

[0046] The upper cutter 300 and the lower cutter 400 of the electrode sheet cutting device according to the second embodiment of the present invention may be arranged symmetrically to each other, with the distance between the cutters being the smallest at one end and the distance between the cutters being the largest at the other end. That is, the upper cutter 300 and the lower cutter 400 may be arranged symmetrically to each other in a right-angled triangle.

[0047] The upper cutter 300 and the lower cutter 400 first contact the electrode sheet 100 at one side, and then the shapes or positions of the upper cutter 300 and the lower cutter 400 may be changed.

[0048] For example, the angle of the upper cutter 300 changes as it approaches the inside of the upper pressure unit 310 to which the upper cutter 300 is connected, and correspondingly, the angle of the lower cutter 400 also changes to correspond to the upper cutter 300 as it approaches the inside of the lower pressure unit 410 to which the lower cutter 400 is connected, and finally, the blades of the upper cutter 300 and the lower cutter 400 may be in complete contact with each other as shown in FIG. 4.

[0049] FIG. 7 is a schematic diagram showing the upper part of the electrode sheet support base according to the present invention.

[0050] 7, the electrode sheet supporter 200 according to the present invention includes a through hole 210 corresponding to a cutting portion where the electrode sheet is cut. The through hole 210 has a shape of a hole having a space through which the lower cutter 400 can pass. The size of the through hole 210 is determined in consideration of a radius caused by the movement or angle change of the lower cutter 400. Here, in order to prevent damage caused by the movement or angle change of the lower cutter 400, the through hole 210 may have an electrode sheet damage prevention part. The electrode sheet damage prevention part is preferably made of a flexible material so as to protect the electrode sheet without damaging the blade of the lower cutter 400.

[0051] FIG. 8 is an enlarged view of a cut surface of an electrode sheet cut by the electrode sheet cutting device according to the present invention.

[0052] As shown in FIG. 8, the cut surface 110 of the electrode according to the present invention refers to a point where the upper cutter and the lower cutter contact each other on the electrode sheet 100, that is, a point where the electrode sheet is cut and cut.

[0053] The cut surface 110 of the electrode may be divided into an electrode tab cut surface and an electrode sheet cut surface according to the portion to be cut. The cutting order and cutting start point of the electrode sheet 100 may be changed according to the type of the cut surface 110 of the electrode.

[0054] FIG. 9 is a schematic diagram of an electrode sheet cutting device according to the present invention and an electrode sheet cut by the device.

[0055] As shown in FIG. 9(i), in order to cut a plurality of electrode tab portions 120 from one electrode sheet 100, a plurality of electrode tab portions 120 can be formed by cutting one electrode sheet 100.

[0056] When manufacturing the electrode sheet 100 as described above, in the step of cutting the electrode sheet 100 (S2), the electrode sheet 100 may be cut in a longitudinal direction or a direction perpendicular thereto to form a single electrode assembly, or may be cut into a concave-convex shape to form an electrode tab portion 120.

[0057] When forming the electrode tab cutting surface 111 for cutting the electrode tabs, it is preferable to cut the electrode sheet 100 in the cutting direction A of the electrode tab protrusion first and then cut the electrode sheet 100 in a portion perpendicular to the protruding direction a of the electrode tab portion 120, i.e., in the electrode tab recess cutting direction b, which is the direction of the electrode sheet 100. Also, it is preferable to cut the electrode tab portion 120 from the protruding point, i.e., the point closest to the electrode tab protrusion, and cut the farthest point last. That is, in the electrode tab recess cutting direction b-1 of the left electrode tab recess cutting direction, the electrode tab portion 120 is formed to the left of the cutting start point, so cutting is started from the left side and then to the right side, and in the right electrode tab recess cutting direction b-2, the electrode tab portion 120 is formed to the right of the cutting start point, so cutting is started from the right side and then to the left side.

[0058] The left electrode tab recess cutting direction b-1 and the right electrode tab recess cutting direction b-2 meet at a point farthest from a point where the electrode tab portion 120 is formed, i.e., at the center of the electrode tab portion 120, and the electrode sheet 100 is cut at this point in a direction perpendicular to the electrode tab recess cutting direction b to form an electrode for a unit cell of an electrode assembly.

[0059] In order to accomplish this, the electrode sheet cutting device according to the present invention includes an upper cutter 300, an upper pressure unit 310, a lower cutter 400, and a lower pressure unit 410, as shown in FIG. 9(ii), and the upper cutter 300 and the lower cutter 400 are deformed as the electrode sheet is cut.

[0060] Here, it is preferable that the upper cutter 300 and the lower cutter 400 are disposed such that their most protruding portions are located at the points closest to the positions where the electrode tab portions 120 are to be formed, and that the upper cutter 300 and the lower cutter 400 are disposed such that their most recessed portions are located at the cut surfaces 112 of the electrode sheet that are cut to form the electrodes for the unit cells.

[0061] FIG. 10 is a diagram showing the results of a virtual simulation of the force applied to the electrode sheet by the electrode sheet cutting device.

[0062] The force applied to the electrode sheet by the electrode sheet cutting device decreases as the area of ​​contact between the electrode sheet cutting device and the electrode sheet increases.

[0063] That is, in the conventional electrode sheet cutting device, the entire area (area=10) comes into uniform contact with the electrode sheet as shown in Figure 10, resulting in a small force (stress=0.1) applied to the electrode sheet, whereas in the electrode sheet cutting device according to the present invention, only a portion (area<10) comes into contact with the electrode sheet first as shown in Figure 10, resulting in a large force (stress>0.1) applied to the electrode sheet. This allows the electrode sheet to be cut quickly and reduces deformation of the electrode sheet.

[0064] Although certain parts of the contents of the present invention have been described in detail above, it will be apparent to those skilled in the art that such specific techniques are merely preferred embodiments and do not limit the scope of the present invention. Various changes and modifications are possible within the scope of the scope and technical ideas of the present invention, and it goes without saying that such changes and modifications are also included in the scope of the attached claims. [Industrial Applicability]

[0065] The electrode sheet cutting device and the electrode sheet cutting method according to the present invention can minimize deformation of the electrode sheet and can easily remove foreign matter formed by cutting the electrode sheet to prevent the foreign matter from affecting the electrodes.

[0066] In addition, the electrodes can be stacked uniformly by cutting the electrode sheet into a certain shape, and when the electrodes are stacked in a pouch-type case, a certain shape can be formed. Furthermore, since the electrodes are stacked to a uniform height, the density and capacity of the electrodes can be improved.

[0067] In addition, since cutting is performed from one side, residues generated by cutting the electrodes are moved to a specific portion, which has the advantage of making it easy to remove the residues. [Explanation of symbols]

[0068] 10, 100 electrode sheet 11, 110 Cut surface of electrode 120 Electrode tab part 111 Electrode tab cut surface 112 Cut surface of electrode sheet 200 Electrode sheet support stand 210 Through hole 30 Cutter 300 Upper Cutter 310 Upper pressure section 400 Lower Cutter 410 Lower pressure section F1 Upper pressure force F2 Lower pressure A Cutting direction B Distance between cutters a Cutting direction of electrode tab protrusion b Electrode tab recess cutting direction b-1 Cutting direction of left electrode tab recess b-2 Cutting direction of right electrode tab recess

Claims

1. an upper cutter located above the electrode sheet and cutting the electrode sheet; a lower cutter positioned corresponding to the upper cutter and in contact with the upper cutter to cut the electrode sheet; an electrode sheet support table located between the upper cutter and the lower cutter, supporting the electrode sheet, and having a through hole corresponding to a cutting portion where the electrode sheet is cut by contacting the upper cutter and the lower cutter; The upper and lower cutters move with a constant force and velocity; The electrode sheet cutting device, in which the upper cutter and the lower cutter first come into contact with each other at the center of the electrode sheet, and then the cutting portion is increased toward the outer periphery of the electrode sheet.

2. The electrode sheet cutting device according to claim 1 , wherein the upper cutter and the lower cutter apply the same force to the electrode sheet.

3. The electrode sheet cutting device according to claim 1 or 2, wherein the upper cutter and the lower cutter move on the electrode sheet at the same speed.

4. The electrode sheet cutting device according to claim 1 , wherein the upper cutter and the lower cutter have the same shape.

5. The electrode sheet cutting device according to any one of claims 1 to 4, further comprising: a cutting device for cutting the electrode sheet to form an electrode tab protrusion.

6. (S1) preparing an electrode sheet on an electrode sheet support table having a through hole formed in a portion of the electrode sheet to be cut; (S2) cutting the electrode sheet using an upper cutter and a lower cutter included in the electrode sheet cutting device according to any one of claims 1 to 5.

7. 7. The electrode sheet cutting method according to claim 6, wherein in step (S2), the electrode sheet is cut in a longitudinal direction or a direction perpendicular thereto to form a single electrode assembly, or cut in an uneven shape to form an electrode tab.

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