Electrode cutter capable of preventing electrode separation

Abstract

Disclosed is an electrode cutter capable of preventing or reducing an elongated linear detachment material generated during a process of cutting an electrode or reducing the length of the detachment material. The electrode cutter includes an upper cutter and a lower cutter, in which a serrated cutting portion is provided on at least one of one surface of the upper cutter and one surface of the lower cutter in a blade length direction. The serrated shape prevents detachment of the material or significantly reduces the length of the detached material.

Description

Technical Field

[0001] The present invention relates to an electrode cutter capable of preventing electrode detachment, an electrode cutting method using the electrode cutter, an electrode manufactured by the method, and an electrode assembly including the electrode. More specifically, the present invention relates to an electrode cutter capable of preventing or reducing burrs or detachment powder generated during the process of cutting an electrode, an electrode cutting method using the electrode cutter, an electrode manufactured by the method, and an electrode assembly including the electrode. Background Art

[0002] A lithium secondary battery includes: an electrode assembly including a positive electrode coated with a positive electrode active material, a negative electrode coated with a negative electrode active material, and a separator positioned between the positive electrode and the negative electrode, the separator configured to prevent a short circuit and allow lithium ions (Li-ions) to move therethrough; a battery case configured to accommodate the electrode assembly; and an electrolyte solution injected into the battery case, the electrolyte solution configured to allow lithium ions to move therethrough.

[0003] The positive electrode and the negative electrode can be manufactured in the form of unit electrodes by coating, drying, and rolling a positive electrode active material and a negative electrode active material on a long strip-shaped positive electrode current collector and a long strip-shaped negative electrode current collector, respectively, and then cutting them into a certain size.

[0004] Conventional electrode cutting equipment for manufacturing such unit electrodes includes: a transfer unit configured to transfer an electrode in a state where a long strip-shaped electrode coated, dried, and rolled with an electrode active material is placed on the transfer unit; and a cutter mounted on one side of the transfer unit. The cutter is divided into an upper cutter and a lower cutter. Specifically, based on the long strip-shaped electrode, the upper cutter is fixed on the upper side, and the lower cutter is mounted on the lower side. When the long strip-shaped electrode is transferred to the electrode cutting equipment, the cutting edge of the upper cutter and the cutting edge of the lower cutter come into contact with each other to cut the long strip-shaped electrode.

[0005] Due to the repeated execution of the cutting process of the upper cutter and the lower cutter, the cutting edge of the cutter is worn or the cutting edge of the cutter is bent, so that the cut portion of the long strip-shaped electrode is not smooth, or burrs or detachment powder are generated. In addition to continuous use, defects may also occur due to installation errors such as an increase in the clearance between the upper cutter and the lower cutter or misalignment between the mounting surfaces of the upper cutter and the lower cutter.

[0006] During the process of cutting a long, sheet-like electrode, problems can occur in the current collector, which is a metal thin film, the positive electrode active material, or the negative electrode active material. The gap between the upper cutter and the lower cutter is small, so the frictional force between the cutter blade and the electrode active material is high. Due to the frictional force, defects may occur in the electrode active material even when the cutter is in a normal state. If the adhesion force in the electrode active material is low or the adhesion force between the electrode active material and the current collector is low, the electrode active material will fall off from the cutting surface of the long, sheet-like electrode, or the electrode active material and the current collector will fall off from the cutting surface of the long, sheet-like electrode, resulting in detachment or the generation of detached powder (hereinafter referred to as "detached material").

[0007] In particular, the detached material generated from the negative electrode is usually in the form of a wire with a small width and a long length. This causes a short circuit where the negative electrode and the positive electrode come into contact with each other, or a bridging phenomenon where the negative electrode and the positive electrode are connected to each other. The detached material mentioned here is not a simple powder, but is attached to the cutting part of the negative electrode or the positive electrode in the form of a slender object such as a wire or a rope. Figure 1 The cutting surface of the negative electrode to which such detached material is attached is shown. In Figure 1 , the negative electrode extends horizontally in the middle, and the detached material extends upward and downward from the negative electrode like a wire. In Figure 1 , the bright or white areas above and below the negative electrode represent the separator.

[0008] When the content of the binder in the electrode active material is increased to improve the adhesion force of the electrode active material, the detached material can be reduced or prevented. In this case, the performance of the battery may deteriorate due to an increase in resistance caused by the increase in the binder content in the electrode.

[0009] Figure 2 is a schematic diagram showing a conventional electrode laminating device 100. Figure 2 The shown electrode laminating device 100 is an example of an electrode manufacturing device for laminating a total of five layers from the top (z-axis direction), namely, the upper and lower electrodes 20, the separator 30, the intermediate electrode 10, the separator 30, and the upper and lower electrodes 20. In Figure 2 , the electrode tabs are omitted.

[0010] Refer to Figure 2, the intermediate electrode 10 and the upper and lower electrodes 20 are respectively cut by a first cutter 40 and a second cutter 50, and after passing through a lamination unit 60, they are manufactured in the form of unit electrodes of a specific size by a third cutter 70. The electrode cutter according to the present invention relates to the first cutter 40 and the second cutter 50 configured to cut the long sheet-like electrodes 10, 20. However, even if the electrodes are not in the form of long sheets but in a cut form, the same problems will be encountered during the process of cutting the electrodes again. Therefore, the electrode cutter is not necessarily only applicable to long sheet-like electrodes.

[0011] Figure 3 is a side view of a conventional electrode cutting device, showing a part of the electrode cutting device, which has a linked assembly structure in which each component of the upper unit and the lower unit is directly and gradually fastened to the main frame. In Figure 3 , an upper cutter 42 and a lower cutter 46 are provided. The electrode is cut through the surfaces where the upper cutter and the lower cutter contact each other.

[0012] Figure 4 is a perspective view showing the upper cutter 42 and the lower cutter 46 of a conventional cutter. Referring to Figure 4 , the conventional upper cutter 42 includes: an upper cutter body 44, which is integrally formed in the shape of a rectangular parallelepiped with a relatively large length and a relatively small thickness, and the lower part of the upper cutter body is inclined upward (z-axis) toward the inside of the rectangular parallelepiped symmetrically with respect to the center in the blade length direction of the rectangular parallelepiped; and a first upper cutter blade 45A and a second upper cutter blade 45B symmetrically arranged with respect to the center 43 of the upper cutter blade. The center 43 of the upper cutter blade is the center in the blade length direction of the lower part of the upper cutter body 44. The first upper cutter blade and the second upper cutter blade are arranged only on the front surface (-y-axis direction) of the upper cutter body 44 in an upwardly inclined shape. The lower cutter 46 includes a lower cutter body 48, which is integrally formed in the shape of a rectangular parallelepiped with a relatively large length and a relatively small thickness. The upper cutter 42 may not have a shape inclined upward (z-axis) toward the inside of the rectangular parallelepiped, and may not have the first upper cutter blade 45A and the second upper cutter blade 45B. The present invention is not necessarily limited to Figure 4 the shape.

[0013] When using Figure 4 the upper cutter and the lower cutter shown to cut the electrode, separated materials as shown in Figure 1 will be generated. Figure 5 is a schematic view showing a conventional electrode assembly in which electrodes including separated materials 12 are stacked. Referring to Figure 5, for example, a conventional electrode assembly 100A includes three positive electrodes 20A, two negative electrodes 10A, and five separators 30, but the shape of the electrode assembly is not limited thereto. Due to the elongated linear release material 12 attached or connected to the negative electrode 10A shown in a darker color, a short circuit in which the negative electrode and the positive electrode come into contact with each other or a bridging phenomenon in which the negative electrode and the positive electrode are connected to each other occurs. The release material 12 can be a negative electrode active material or a negative electrode current collector. In many cases, the release material is a negative electrode active material.

[0014] Patent Document 1 relates to a device for cutting an electrode plate, which is configured to reduce the occurrence of burrs generated during cutting of the electrode plate and remove the generated foreign matter. Patent Document 1 discloses a gap adjusting device configured to automatically adjust the gap between an upper cutter and a lower cutter.

[0015] Patent Document 2 discloses a device configured to remove foreign matter generated during cutting.

[0016] Patent Document 3 discloses a cartridge blade configured to maintain a constant gap between an upper cutter and a lower cutter. With the cartridge blade, it is easy to adjust the gap and balance between the upper cutter and the lower cutter.

[0017] Patent Document 4 discloses a unit cell manufacturing device including an L-shaped cutter corresponding to the shape of an electrode to be cut and a unit cell manufacturing method using the device, wherein the L-shaped cutter includes a long blade similar to a conventional upper cutter and a lower cutter.

[0018] Patent Document 5 discloses an electrode assembly including a cutout capable of serrating its outer peripheral end portion. Specifically, Patent Document 5 is a technology for a small cylindrical battery, in which the entire outer periphery of the cylindrical electrode assembly is formed into a serrated shape in order to keep the outer shape itself in a cylindrical shape.

[0019] Conventionally, as described above, the gap or parallelism between the upper cutter and the lower cutter is adjusted to remove burrs of the metal thin film as a current collector generated by cutting. The release material according to the present invention can also be caused by the adhesion of the electrode active material itself and can be generated from the upper cutter and the lower cutter in a normal state. Therefore, this problem cannot be solved only by the conventional adjustment of the gap or alignment between the upper cutter and the lower cutter. Even when using a cutter with a special shape, there is a region with a long blade similar to a conventional upper cutter and a lower cutter, and this blade seems to be designed to define the shape of the electrode assembly. In addition, the prior art not only does not recognize the problem of the release material solved by the present invention, but also does not seem to solve this problem.

[0020] Korean Patent Application Publication No. 2006-0027258 (“Patent Document 1”)

[0021] Korean Patent Application Publication No. 2017-0097515 (“Patent Document 2”)

[0022] Korean Patent Application Publication No. 2022-0013246 (“Patent Document 2”)

[0023] Korean Patent Application Publication No. 2023-0042561 (“Patent Document 4”)

[0024] Korean Registered Patent Publication No. 2064926 (“Patent Document 5”) Summary of the Invention

[0025] Technical Problem

[0026] The present invention is made in view of the above problems, and an object of the present invention is to provide an electrode cutter that can prevent or reduce the detached material generated during the process of cutting an electrode or reduce the length of the detached material, an electrode cutting method using the electrode cutter, an electrode manufactured by this method, and an electrode assembly including the electrode.

[0027] Technical Solution

[0028] To achieve the above object, the present invention provides an electrode cutter, the electrode cutter includes an upper cutter and a lower cutter configured to cut an electrode, wherein the upper cutter and the lower cutter contact each other to cut the electrode, and a serrated cutting portion is provided along the length direction of the cutting edge on at least one of a surface of the upper cutter and a surface of the lower cutter.

[0029] The electrode cutter can generally be used in an electrode assembly manufacturing apparatus, the electrode assembly manufacturing apparatus including: at least one transfer roller configured to move an electrode sheet; a lamination unit configured to laminate the electrode sheet by applying heat and pressure to the electrode sheet; and a grooving cutter configured to groove the electrode sheet to form an electrode.

[0030] The electrode can be a positive electrode or a negative electrode, and can be a positive electrode, a negative electrode, a positive electrode and a negative electrode according to the types of active materials and binders used in the positive electrode and the negative electrode.

[0031] The rear surface of the upper cutter and the rear surface of the lower cutter, specifically, the rear surface of the lower part of the upper cutter and the rear surface of the upper part of the lower cutter, can be in contact with each other to cut the electrode. The cutting portion can be provided on at least one of the rear surface of the upper cutter and the rear surface of the lower cutter, specifically, on at least one of the rear surface of the lower part of the upper cutter and the rear surface of the upper part of the lower cutter. In addition, the cutting portion can be provided on each of the rear surface of the upper cutter and the rear surface of the lower cutter, specifically, can be provided on each of the rear surface of the lower part of the upper cutter and the rear surface of the upper part of the lower cutter. In this case, the cutting portion can be provided on the respective surfaces where the upper cutter and the lower cutter are in contact with each other.

[0032] The cutting portion can be provided only on a part of the upper cutter and / or the lower cutter. Specifically, the cutting portion can be provided only on a part of the upper cutter and / or the lower cutter along the length direction of the cutting edge. As another example, the cutting portion can be provided only on a part of the upper cutter and / or the lower cutter along a direction perpendicular to the length direction of the cutting edge. As yet another example, the cutting portion can be provided only on a part of the upper cutter and / or the lower cutter along the length direction of the cutting edge, and can be provided only on a part of the upper cutter and / or the lower cutter along a direction perpendicular to the length direction of the cutting edge.

[0033] The cutting portion can be provided on the entire upper cutter and the entire lower cutter. In this case, the entire upper cutter and the entire lower cutter can be formed in a serrated shape.

[0034] The serrated shape can be at least one of a triangular waveform shape, a polygonal waveform shape having four or more corners, and a curved waveform shape.

[0035] The serrated shape can be a repetition of the same shape or a series of different shapes.

[0036] One segment of the serrated shape can have a length of 3 mm or less, preferably 2 mm or less. The segment mentioned here refers to the segment when the serrated shape is a polygon, and when the serrated shape is a curve, the segment refers to the length between the sharply turning parts of the curve shape.

[0037] The upper cutter can be formed as a whole in the shape of a rectangular parallelepiped with a relatively large length and a relatively small thickness, and the lower cutter can also be formed as a whole in the shape of a rectangular parallelepiped with a relatively large length and a relatively small thickness. In this case, the cutting portion can be provided on the rear surface of the upper cutter and / or the lower cutter.

[0038] Another form of the upper cutter may include: an upper cutter body, which is integrally formed in the shape of a cuboid with a relatively large length and a relatively small thickness, and the lower part of the upper cutter body is inclined upward toward the inside of the cuboid symmetrically with respect to the center in the length direction of the cutting edge; and a first upper cutter edge and a second upper cutter edge symmetrically arranged with respect to the central part of the upper cutter edge, where the central part of the upper cutter edge is the center of the lower part of the upper cutter body in the length direction of the cutting edge. The first upper cutter edge and the second upper cutter edge are arranged in an upwardly inclined shape only on the front surface of the upper cutter body, and the cutting part may be arranged on the rear surface of each of the first upper cutter edge and the second upper cutter edge.

[0039] Another form of the upper cutter may also only include an upper cutter body that is inclined upward toward the inside of the cuboid. In this case, the cutting part may be arranged on the rear surface of the upper cutter or the upper cutter body.

[0040] Another form of the upper cutter may also only include a first upper cutter edge and a second upper cutter edge. In this case, the cutting part may be arranged on the rear surface of each of the first upper cutter edge and the second upper cutter edge.

[0041] The lower cutter may include: a lower cutter body, which is integrally formed in the shape of a cuboid with a relatively large length and a relatively small thickness; and a lower cutter edge, which is arranged in an upwardly inclined shape only on the front surface of the lower cutter body, and the cutting part may be arranged on the rear surface of the lower cutter edge.

[0042] Another form of the lower cutter may not have the lower cutter edge. In this case, the cutting part may be arranged on the rear surface of the lower cutter body.

[0043] The electrode cutter may further include a detachment material removal unit configured to remove the detachment material and / or burrs generated during the cutting of the electrode.

[0044] In addition, the present invention provides a method for cutting an electrode using the electrode cutter, an electrode manufactured by the electrode cutter, an electrode assembly including the electrode, a battery module or battery pack including the electrode assembly, and a product including the electrode assembly.

[0045] The present invention provides an electrode assembly formed by stacking electrodes and separators, wherein at least one of the electrodes has a sawtooth shape formed on at least one side where no electrode tab protrudes.

[0046] One segment of the sawtooth shape may have a length of 3 mm or less, preferably 2 mm or less. The segment mentioned herein refers to the segment when the sawtooth shape is a polygon, and when the sawtooth shape is a curve, the segment refers to the length between the portions where the curve shape makes a sharp turn.

[0047] In addition, the present invention can provide any combination of the above solutions.

[0048] Advantageous Effects

[0049] According to the present invention, an electrode cutter capable of preventing or reducing the generation of elongated strip-shaped detached materials or reducing the length of the detached materials during the process of cutting an electrode, an electrode cutting method using the electrode cutter, an electrode manufactured by the method, and an electrode assembly including the electrode can be provided.

[0050] The electrode cutter according to the present invention is provided with a sawtooth-shaped cutting portion. Therefore, even if elongated strip-shaped detached materials are generated, since the length of each cutting edge corresponding to the sawtooth shape is small, the length of the detached materials can be reduced, thereby preventing or reducing short circuits where the negative electrode and the positive electrode come into contact with each other or bridging phenomena where the negative electrode and the positive electrode are connected to each other. Brief Description of the Drawings

[0051] Figure 1 is a photograph showing a cut surface of a conventional negative electrode where detached materials are generated.

[0052] Figure 2 is a schematic diagram showing a conventional electrode laminating device.

[0053] Figure 3 is a side view showing a conventional electrode cutting device.

[0054] Figure 4 is a perspective view showing an upper cutter and a lower cutter of a conventional cutter.

[0055] Figure 5 is a schematic diagram showing a conventional electrode assembly in which electrodes including detached materials are stacked.

[0056] Figure 6 is a perspective view showing an upper cutter and a lower cutter of a cutter according to a first embodiment of the present invention.

[0057] Figure 7 is a perspective view showing the front surface and the rear surface of each of the upper cutter and the lower cutter according to a first embodiment of the present invention.

[0058] Figure 8 are a front view, a side view, and a bottom view showing the rear surface of the upper cutter according to the first embodiment of the present invention, and an enlarged view showing the cutting part.

[0059] Figure 9 is a schematic view showing the upper cutter of the cutter according to the second embodiment of the present invention.

[0060] Figure 10 is a schematic view showing the negative electrode when using the cutter according to the present invention.

[0061] Figure 11 is a schematic view showing an electrode assembly in which electrodes according to the present invention are stacked. Detailed Embodiments

[0062] Now, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present invention pertains can easily implement the preferred embodiments of the present invention. However, when the working principles of the preferred embodiments of the present invention are described in detail, the detailed description thereof will be omitted when the known functions and configurations incorporated herein may obscure the subject matter of the present invention.

[0063] In addition, the same reference numerals will be used throughout the drawings to refer to components that perform similar functions or operations. In the case where a component is referred to as being connected to another component throughout the application, the component can be directly connected to the other component, and can also be indirectly connected to the other component through other components. In addition, unless otherwise specified, including a certain element does not mean excluding other elements, but means that such an element can be further included.

[0064] In addition, unless otherwise specifically restricted, the description of embodying an element by limitation or addition can be applied to all inventions and does not limit a specific invention.

[0065] In addition, in the description of the present invention and the claims of this application, unless otherwise specified, the singular form is intended to include the plural form.

[0066] In addition, in the description of the present invention and the claims of this application, unless otherwise specified, "or" includes "and". Therefore, "including A or B" means three cases, namely, the case of including A, the case of including B, and the case of including both A and B.

[0067] In addition, unless the context clearly indicates otherwise, all numerical ranges include the lowest value, the highest value, and all intermediate values therebetween.

[0068] The embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0069] Figure 6 is a perspective view showing an upper cutter and a lower cutter of a cutter according to a first embodiment of the present invention, Figure 7 is a perspective view showing a front surface and a rear surface of each of the upper cutter and the lower cutter according to the first embodiment of the present invention.

[0070] Figure 7 (a) and (b) of show the front surface and the rear surface of the upper cutter, respectively, Figure 7 (c) and (d) of show the front surface and the rear surface of the lower cutter, respectively. Among the upper cutter 142 and the lower cutter 146 configured to cut an electrode, the rear surface of the upper cutter 142 and the rear surface of the lower cutter 146 are in contact with each other to cut the electrode. Figure 6 Generally shows the arrangement of the upper cutter 142 and the lower cutter 146 for cutting an electrode. Serrated cutting portions 149A and 149B are respectively provided on the rear surfaces of the upper cutter 142 and the lower cutter 146 along the length direction of the cutting edge. In all the figures, x, y, and z representing coordinates are based on Figure 4 or Figure 6 set as a reference.

[0071] The upper cutter 142 includes: an upper cutter body 144, which is integrally formed in the shape of a rectangular parallelepiped having a relatively large length in the x direction and a relatively small thickness in the y direction, and the lower part of the upper cutter body is symmetric with respect to the center of the rectangular parallelepiped in the x direction and is inclined upward in the z direction, where the z direction is the direction toward the inside of the rectangular parallelepiped and the x direction is the cutting edge length direction; and a first upper cutter edge 145A and a second upper cutter edge 145B symmetrically provided with respect to the center 143 of the upper cutter edge. The center 143 of the upper cutter edge is the center of the lower part of the upper cutter body 144 in the cutting edge length direction. The first upper cutter edge and the second upper cutter edge are provided only on the -y direction surface of the upper cutter body 144 in a shape inclined in the z direction as the upward direction. The -y direction surface of the upper cutter body is the front surface of the upper cutter body. Among them, the cutting portion 149A is provided on the y direction surface of each of the first upper cutter edge 145A and the second upper cutter edge 145B, and the y direction surface is the rear surface of each of the first upper cutter edge and the second upper cutter edge. The cutting portion 149A is provided on the surface of the upper cutter 142 that contacts the lower cutter 146.

[0072] The lower cutter 146 includes: a lower cutter body 148 which is integrally formed in the shape of a rectangular parallelepiped having a relatively large length and a relatively small thickness; and a lower cutter blade 147 which is provided only on the y-direction surface of the lower cutter body 148 in an inclined shape, the y-direction surface of the lower cutter body being the front surface of the lower cutter body, wherein the cutting portion 149B is provided only on the y-direction surface of the lower cutter blade 147, the y-direction surface of the lower cutter blade being the rear surface of the lower cutter blade. The width of the lower cutter blade 147 in the -z direction perpendicular to the blade length direction may be smaller than the width of the first upper cutter blade 145A or the second upper cutter blade 145B in the z direction perpendicular to the blade length direction.

[0073] Although not shown in the figures, but as with Figure 6 and Figure 7 The cutting portions 149A, 149B shown are different, the cutting portion may be provided only on a part of the upper cutter 142 and / or a part of the lower cutter 146. Specifically, the cutting portion may be provided only on a part of the rear surface of the first upper cutter blade 145A, a part of the rear surface of the second upper cutter blade 145B, and a part of the rear surface of the lower cutter blade 147. In a first example, the cutting portion may be provided only on a part of the rear surface of each of the first upper cutter blade 145A and the second upper cutter blade 145B along the blade length direction. In a second example, the cutting portion may be provided only on a part of the rear surface of each of the first upper cutter blade 145A and the second upper cutter blade 145B along a direction perpendicular to the blade length direction. In a third example, the cutting portion may be provided only on a part of the rear surface of each of the first upper cutter blade 145A and the second upper cutter blade 145B along the blade length direction, and the cutting portion may be provided only on a part of the rear surface of each of the first upper cutter blade 145A and the second upper cutter blade 145B along a direction perpendicular to the blade length direction. Since the lower cutter 146 must engage with the upper cutter 142, in the above three cases, the cutting portion is also provided only in a part of the lower cutter 146.

[0074] Specifically, Figure 6 and Figure 7 The cutting portions 149A, 149B shown are provided on the entire rear surfaces of the first upper cutter blade 145A, the second upper cutter blade 145B, and the lower cutter blade 148 along the blade length direction, and are provided on the entire rear surfaces of the first upper cutter blade 145A, the second upper cutter blade 145B, and the lower cutter blade 148 along a direction perpendicular to the blade length direction. That is, in Figure 6 and Figure 7In this case, a first upper cutter blade 145A and a second upper cutter blade 145B are formed, and cutting portions 149A and 149B are provided on specific portions thereof.

[0075] Since the rear surfaces of the upper cutter and the lower cutter contact each other to cut the electrode, the first upper cutter blade, the second upper cutter blade, and the lower cutter blade may not be necessary. In addition, the shape of the upper cutter body that is inclined upward in the z direction, where the z direction is the direction toward the inside of the rectangular parallelepiped, may not be necessary. However, considering the actual gap between the upper cutter and the lower cutter, the stress applied to the cutting portions, the discharge of the cutting portions, etc., if each of the first upper cutter blade, the second upper cutter blade, and the lower cutter blade has an inclined shape and an inclined surface, cutting can be performed more effectively.

[0076] That is, different from Figure 6 and Figure 7 the first upper cutter blade and the second upper cutter blade may be configured not to have an inclined portion in the x-axis direction, not to have an inclined portion in the z-axis direction, or not to have an inclined portion in the x-axis direction and not to have an inclined portion in the z-axis direction (not shown). The lower cutter blade may also not have an inclined portion. If the cutting portions are provided on both the upper cutter and the lower cutter, the cutting portions may be provided to mesh with each other. In this case, different from the contact between the rear surface of the conventional upper cutter and the rear surface of the lower cutter, the upper cutter and the lower cutter must be arranged closer to each other by the intersecting dimension of the cutting portions. If the cutting portion is provided only on the upper cutter or the lower cutter, the upper cutter and the lower cutter are arranged in the same manner as the contact between the rear surface of the conventional upper cutter and the rear surface of the lower cutter.

[0077] Figure 8 FIG. (a) is a front view, FIG. (b) is a side view, and FIG. (c) is a bottom view showing the rear surface of the upper cutter 142 according to the first embodiment of the present invention, and FIG. is an enlarged view showing the cutting portion 149A. As a specific example, the length of the upper cutter 142 in the x direction, which is the blade length direction, may be 400 mm, and the length of the upper cutter in the z direction, which is the upper cutter height, may be 100 mm. Since the cutting portion 149A of the upper cutter and the cutting portion 149B of the lower cutter mesh with each other, the saw teeth must have the same pitch and angle, and when the upper cutter 142 and the lower cutter 146 contact each other, the cutting portions must mesh with each other. In the example of the cutting portion 149A, the saw teeth have a pitch (P) of 5.5 mm and an angle (θ) of 90 degrees.

[0078] Although only the case where the saw teeth have the same shape is shown in the embodiment of the present invention, the present invention is not limited thereto. In addition, although Figure 1A conventional negative electrode is shown, but the electrode cutter according to the present invention can be applied to all negative electrodes, positive electrodes, and current collectors. Herein, the negative electrode and the positive electrode specifically refer to the negative electrode active material and the positive electrode active material, respectively. Even if detached materials are generated, since the size of the separator is larger than the size of the electrode active material layer, detached materials below a certain size will not cause short circuits or bridging. Considering this, the present invention limits the size of the possible detached materials by forming the cutting portion into a serrated shape.

[0079] The size of the detached materials generated during actual cutting, precisely the length of the detached materials, is determined by the length of a line segment of the serrated shape of the cutting portion. The line segment mentioned here refers to the line segment when the serrated shape is a polygon, and when the serrated shape is a curve, the line segment refers to the length between the sharply turning parts of the curve shape.

[0080] To prevent short circuits, the length of a line segment of the serrated shape of the cutting portion is 3 mm or less, preferably 2 mm or less. However, the angle (θ) must be less than 180 degrees to form the serrated shape. As the angle (θ) approaches 0, the overall width of the serrated shape increases, so the amount of active material discarded by the cutting portion increases. Considering only this point, it is desirable to make the angle (θ) larger, but due to the viscosity of the active material, the gap between the upper cutter and the lower cutter, etc., there may be a problem that the detached materials are not cut off and are connected, so in actual applications, an angle less than 180 degrees needs to be formed.

[0081] Considering these points, it can be seen that the serrated shape does not require the line segment length and the angle to be the same, and the object of the present invention can be achieved only by forming the serrated shape. Referring to the serrated shape presented by the present invention through examples and the above description, it is obvious to those of ordinary skill in the art that the serrated shape can not only be transformed into a triangular waveform shape illustrated in the figures as an example, but also be transformed into other polygonal waveform shapes and curve waveform shapes.

[0082] Figure 9 It is a schematic diagram showing the upper cutter 242 of the cutter according to the second embodiment of the present invention. Figure 9 The shown upper cutter 242 is configured to provide the cutting portion 249A on the entire upper cutter body without distinguishing between the front surface and the back surface. Since the shape of the lower cutter must correspond to the shape of the upper cutter 242, the shape of the lower cutter is similar to the shape of the upper cutter 242. Although Figure 9 the serrated shape is shown as larger than Figure 8 the serrated shape, this is an example, and the serrated shape is preferably the same size as described with reference to Figure 8 and can be deformed as described with reference to Figure 8 ​

[0083] Since the electrode is cut in the sawtooth shape of the cutting portion, it is desirable to limit the length of one end of the sawtooth shape so that the maximum size of the detached material does not exceed the thickness of the electrode. However, since the cutting shape is a sawtooth shape, even if the length of one end of the sawtooth shape is greater than the thickness of the electrode, the sawtooth shape does not linearly elongate the detached material, or the detached material is likely to break again after being cut by the sawtooth shape, thereby reducing the length of the detached material. Therefore, the length of one end of the sawtooth shape is not limited only by the thickness of the electrode.

[0084] Figure 10 FIG. is a schematic view showing the negative electrode 110A when using the cutter according to the present invention. Figure 10 In (a) of FIG., the left and right sides of the side where the negative electrode tab protrudes are cut into a sawtooth shape. Figure 10 In (b) of FIG., the case where the positive electrode 120A is stacked on the negative electrode 110A for comparison is shown. The sawtooth shape is shown somewhat exaggerated compared to the actual scale. If the negative electrode is larger than the positive electrode, when both sides of the negative electrode are cut into a sawtooth shape, the minimum width of the portion cut into the sawtooth shape is preferably greater than the width of the positive electrode. This is to reduce the possibility of the negative electrode and the positive electrode coming into contact with each other even if detached material is generated.

[0085] As referred to Figure 8 above, applied to Figure 10 the length of one segment of the sawtooth shape of the cutting portion of the negative electrode shown in FIG. is 3 mm or less, preferably 2 mm or less. In Figure 10 , as Figure 8 shown in FIG., the angle formed by the sawtooth shape is 90 degrees, but the present invention is not limited thereto. However, in order to form a sawtooth shape, the angle must be less than 180 degrees. As the angle (θ) approaches 0, the overall width of the sawtooth shape increases, so the amount of active material discarded by the cutting portion increases. Considering only this point, it is desirable to make the angle (θ) larger, but due to the viscosity of the active material, the gap between the upper cutter and the lower cutter, etc., there may be a problem that the detached material is not cut off and connected, so in practical applications, an angle less than 180 degrees needs to be formed. Figure 11 FIG. is a schematic view showing the electrode assembly 100B in which the electrodes according to the present invention are stacked. Referring to Figure 11 , as an example, the electrode assembly 100B includes three positive electrodes 20A, two negative electrodes 110A, and five separators 30, but the shape of the electrode assembly is not limited thereto. Compared with the detached material 12 of the conventional electrode assembly (see Figure 5 ), the length of the elongated linear detached material 12A attached to the negative electrode 110A is greatly reduced. As a result, it is possible to prevent or reduce the short circuit in which the negative electrode and the positive electrode come into contact with each other or the bridging phenomenon in which the negative electrode and the positive electrode are connected to each other that may occur in the conventional electrode assembly 100A.

[0086] Those skilled in the art to which the present invention pertains will understand that various applications and modifications can be made within the scope of the present invention based on the above description.

[0087] (Description of reference numerals)

[0088] 100: Electrode laminating device

[0089] 100A, 100B: Electrode assemblies

[0090] 10: Intermediate electrode

[0091] 10A, 110A: Negative electrode

[0092] 12, 12A: Release material

[0093] 20: Upper and lower electrodes

[0094] 20A, 120A: Positive electrode

[0095] 30: Diaphragm

[0096] 40: First cutter

[0097] 50: Second cutter

[0098] 60: Laminating unit

[0099] 70: Third cutter

[0100] 42, 142, 242: Upper cutters

[0101] 43, 143: Central part of the cutting edge of the upper cutter

[0102] 44, 144: Bodies of the upper cutters

[0103] 45A, 145A: First cutting edges of the upper cutter

[0104] 45B, 145B: Second cutting edges of the upper cutter

[0105] 46, 146: Lower cutters

[0106] 147: Cutting edge of the lower cutter

[0107] 48, 148: Bodies of the lower cutters

[0108] 149A, 149B, 249A: Cutting parts

[0109] P: Tooth pitch

[0110] θ: Angle.

Claims

1. An electrode cutter, comprising an upper cutter and a lower cutter configured to cut an electrode, wherein, the upper cutter and the lower cutter are in contact with each other to cut the electrode, and a cutting portion in a sawtooth shape is provided along the length direction of the cutting edge on at least one of a surface of the upper cutter and a surface of the lower cutter.

2. The electrode cutter according to claim 1, wherein, the rear surface of the upper cutter and the rear surface of the lower cutter are in contact with each other to cut the electrode, and the cutting portion is provided on at least one of the rear surface of the upper cutter and the rear surface of the lower cutter.

3. The electrode cutter according to claim 2, wherein the cutting portion is provided on each of the rear surface of the upper cutter and the rear surface of the lower cutter.

4. The electrode cutter according to claim 2, wherein the cutting portion is provided only on a part of the upper cutter and / or the lower cutter along the length direction of the cutting edge.

5. The electrode cutter according to claim 2, wherein the cutting portion is provided only on a part of the upper cutter and / or the lower cutter along a direction perpendicular to the length direction of the cutting edge.

6. The electrode cutter according to claim 1, wherein, When the cutting portion is provided on the upper cutter and the lower cutter, the cutting portion is provided on the entire upper cutter and the entire lower cutter.

7. The electrode cutter according to claim 1, wherein the sawtooth shape is at least one of a triangular waveform shape, a polygonal waveform shape having four or more corners, and a curved waveform shape.

8. The electrode cutter according to claim 1, wherein the sawtooth shape is a repetition of the same shape or a series of different shapes.

9. The electrode cutter according to claim 1, wherein a line segment of the sawtooth shape has a length of 3 mm or less.

10. The electrode cutter according to claim 1, wherein, the upper cutter includes an upper cutter body, the upper cutter body is integrally formed in the shape of a rectangular parallelepiped having a larger length and a smaller thickness, and the cutting portion is provided on the rear surface of the upper cutter body.

11. The electrode cutter according to claim 1, wherein, the upper cutter includes: an upper cutter body, the upper cutter body is integrally formed in the shape of a rectangular parallelepiped having a larger length and a smaller thickness, a lower portion of the upper cutter body is symmetric with respect to the center in the length direction of the cutting edge of the rectangular parallelepiped and is inclined upward toward the inside of the rectangular parallelepiped; and a first upper cutter blade and a second upper cutter blade symmetrically provided with respect to the center of the upper cutter blade, the center of the upper cutter blade is the center in the length direction of the cutting edge of the lower portion of the upper cutter body, the first upper cutter blade and the second upper cutter blade are provided only on the front surface of the upper cutter body in an upwardly inclined shape, and the cutting portion is provided on the rear surface of each of the first upper cutter blade and the second upper cutter blade.

12. The electrode cutter according to claim 1, wherein, The lower cutter includes a lower cutter body, and the lower cutter body is integrally formed in the shape of a rectangular parallelepiped having a relatively large length and a relatively small thickness, and the cutting portion is provided on the rear surface of the lower cutter body.

13. The electrode cutter according to claim 1, wherein the lower cutter includes: a lower cutter body integrally formed in the shape of a rectangular parallelepiped having a relatively large length and a relatively small thickness; and a lower cutter blade provided only on the front surface of the lower cutter body in an upwardly inclined shape, and the cutting portion is provided on the rear surface of the lower cutter blade.

14. The electrode cutter according to claim 1, further comprising a detachment material removing unit configured to remove detachment materials and / or burrs generated during cutting of the electrode.

15. A method of cutting an electrode using the electrode cutter according to any one of claims 1 to 14.

16. An electrode manufactured by the method according to claim 15.

17. An electrode assembly including the electrode according to claim 16.

18. An electrode assembly formed by stacking an electrode and a separator, wherein at least one of the electrodes has a serrated shape formed on at least one side where no electrode tab protrudes.

19. The electrode assembly according to claim 18, wherein one segment of the serrated shape has a length of 3 mm or less.

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