Electrode, electrode assembly, and electrode cutting device

Abstract

The present invention relates to an electrode, and provides an electrode including: a current collector formed of a metal foil; and a first electrode active material layer coated on one side of the current collector, the first electrode active material layer having a compressed portion formed by compressing a predetermined region, the compressed portion being formed at an end of the first electrode active material layer and having a higher density than a region positioned inside the compressed portion. The present invention also relates to an electrode assembly, which includes at least one of a separator and an electrode stacked and wound, and includes a core formed at the center by winding the separator and the electrode. The electrode includes a current collector formed of metal foil, and a first electrode active material layer coated on one side of the current collector, the first electrode active material layer having a compressed portion formed by compressing a predetermined area, the compressed portion being formed at an end of the first electrode active material layer and having a higher density than an area located inside the compressed portion. The present invention also relates to an electrode cutting device, and provides an electrode cutting device including: a cutter provided to cut a current collector coated with an electrode active material; and a pressure unit protruding from both sides of the cutter at a position spaced apart from an end of the cutter, and applying pressure to one side of the cut surface cut by the cutter to increase the density of the electrode active material.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0099955, filed on July 31, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an electrode, an electrode assembly, and an electrode cutting device, and more particularly to an electrode, an electrode assembly, and an electrode cutting device in which the density of an electrode active material layer coated on a current collector is increased. [Background technology]

[0003] Secondary batteries are highly applicable to a wide variety of products and have electrical properties with high energy density. They are used not only in portable electronic devices but also in electric vehicles, hybrid vehicles, power storage devices, and other devices powered by electrical sources. Secondary batteries are attracting attention as a new energy source that is environmentally friendly and improves energy efficiency because they produce no by-products, in addition to their primary advantage of dramatically reducing the use of fossil fuels.

[0004] The electrode assembly included in the secondary battery includes a separator and an electrode, and depending on the manufacturing method of the electrode assembly, it can be classified into a jelly-roll type in which a separator is interposed between a sheet-like positive electrode and a negative electrode coated with an electrode active material and wound up, a stack type in which multiple positive electrodes and negative electrodes are stacked in order with a separator interposed therebetween, and a stack / folding type in which a stack type unit cell is wound up on a long separating film.

[0005] However, the manufacturing process of a jelly-roll type electrode assembly requires a process of cutting the electrodes to the intended length. When the cut electrodes and separator are wound up to assemble the electrode assembly, there is a problem that the separator may be damaged, such as broken, due to steps formed on the cut surfaces of the electrode ends. Furthermore, there is a problem that the current collector and the electrode active material layer are easily separated at the cut surfaces of the electrode, which may cause an electrical short circuit. Therefore, there is a need to develop a technology to solve these problems. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an electrode in which the ends of an electrode active material layer coated on a current collector are compressed to form the ends with a higher density than an inner region so that the ends do not peel off from the current collector, and the ends of the electrode are sloped to reduce damage to a separator that comes into contact with the ends of the electrode during manufacturing of the electrode assembly, an electrode assembly including the electrode, and an electrode cutting device. [Means for solving the problem]

[0007] In a first embodiment of the present invention, the present invention provides an electrode including: a current collector formed of a metal foil; and a first electrode active material layer coated on one surface of the current collector, the first electrode active material layer having a compressed portion formed by compressing a predetermined region by pressure, the compressed portion being formed at an end of the first electrode active material layer and having a higher density than a region positioned more inward than the compressed portion.

[0008] Also, an end of the compressed portion may coincide with an end of the current collector.

[0009] The battery may further include a second electrode active material layer coated on the other surface of the current collector.

[0010] The second electrode active material layer may be formed asymmetrically with respect to the first electrode active material layer with respect to the current collector.

[0011] The upper surface of the compressed portion may be formed as a continuous inclined surface facing the current collector.

[0012] The compression portion may be inclined such that the height of the upper surface of the compression portion gradually decreases toward the current collector.

[0013] In addition, as a second embodiment of the present invention, the compressed portion may include a first portion that forms an end of the compressed portion and is formed in a direction perpendicular to one surface of the current collector, a second portion that is spaced a predetermined distance from the first portion along the inclination direction and is formed in a direction perpendicular to one surface of the current collector, and a third portion that is formed between the first portion and the second portion and is formed in a direction perpendicular to the second portion.

[0014] In addition, as a third embodiment of the present invention, a plurality of the second parts and third parts may be provided, the plurality of second parts may be formed spaced apart from each other along the inclination direction, and the plurality of third parts may be formed to connect the first part and the second part, and the plurality of second parts to each other.

[0015] In addition, as a fourth embodiment of the present invention, there is provided an electrode assembly in which at least one of a separator and an electrode is stacked and wound, the electrode assembly including a core formed at the center by winding the separator and the electrode, the electrode including a current collector formed of metal foil, and a first electrode active material layer coated on one side of the current collector and having a compressed portion formed by compressing a predetermined area, the compressed portion being formed at an end of the first electrode active material layer and having a higher density than an area located inside the compressed portion.

[0016] The compression portion may be disposed facing the core so that the separator can cover it.

[0017] The upper surface of the compressed portion may be formed as a continuous inclined surface facing the current collector.

[0018] The compression portion may be inclined such that the height of the upper surface of the compression portion gradually decreases toward the current collector.

[0019] In addition, as a fifth embodiment of the present invention, the present invention provides an electrode cutting device including: a cutter provided to cut a current collector coated with an electrode active material; and a pressure unit protruding from both sides of the cutter at a position spaced apart from an end of the cutter, and applying pressure to one side of the cut surface cut by the cutter to increase the density of the electrode active material.

[0020] The pressure unit may include an inclined pressure surface having a continuous inclination formed so as to become farther from both side surfaces of the cutter as it becomes farther from the end of the cutter.

[0021] The pressure unit may include an inclined pressure surface having an inclination such that the protruding height increases intermittently as the pressure unit moves away from the end of the cutter.

[0022] In addition, as a sixth embodiment of the present invention, the inclined pressure surface may include a plurality of first pressure surfaces spaced a predetermined distance apart along the inclined direction and formed in a direction perpendicular to one side of the cutter, and a second pressure surface formed between the plurality of first pressure surfaces and formed in a direction perpendicular to the first pressure surface.

[0023] In addition, as a seventh embodiment of the present invention, a plurality of the second pressing surfaces may be provided, and the plurality of second pressing surfaces may be formed to connect the plurality of first pressing surfaces to each other. [Effects of the Invention]

[0024] The present invention can improve the adhesion between the electrode active material layer and the current collector by compressing the ends of the electrode active material layer coated on the current collector, thereby reducing the possibility that the electrode active material layer will peel off from the current collector.

[0025] In addition, by forming a slope at the electrode end, the contact area between the electrode end and the separator is increased during the manufacture of the electrode assembly, thereby reducing damage to the separator caused by a step formed by the thickness of the electrode. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a perspective view showing the shape of an electrode cut by the electrode cutting device of the present invention. FIG. [Figure 2] 1 is a cross-sectional view showing the shape of an electrode in which a continuous slope is formed at the end of a first electrode active material layer in a first embodiment of the present invention. [Figure 3] FIG. 10 is a cross-sectional view showing the shape of an electrode in which intermittent slopes are formed at the edge of a first electrode active material layer in a second embodiment of the present invention. [Figure 4] 10 is a cross-sectional view showing the shape of an electrode in which intermittent slopes are formed at the edge of a first electrode active material layer in a third embodiment of the present invention. FIG. [Figure 5] FIG. 10 is a perspective view showing the shape of an electrode assembly in a fourth embodiment of the present invention. [Figure 6] FIG. 6 is an enlarged cross-sectional view showing the dotted line area in FIG. 5 in a fourth embodiment of the present invention. [Figure 7] 10 is a cross-sectional view showing the shape of a cross section taken along the line AA' of the electrode cutting device of FIG. 1 in a fifth embodiment of the present invention. FIG. [Figure 8] FIG. 13 is a cross-sectional view showing the shape of a cross section of an electrode cutting device taken in a direction perpendicular to the length direction in a sixth embodiment of the present invention. [Figure 9] FIG. 13 is a cross-sectional view showing the shape of a cross section of an electrode cutting device taken in a direction perpendicular to the length direction in a seventh embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments set forth herein.

[0028] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that may obscure the gist of the present invention will be omitted, and in this specification, when adding reference symbols to components in each drawing, the same or similar reference symbols will be used throughout the specification to refer to the same or similar components.

[0029] Furthermore, the terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary and dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, in accordance with the principle that an inventor can appropriately define the concept of a term in order to best explain his or her invention.

[0030] First embodiment 1 and 2, according to a first embodiment of the present invention, an electrode 10 may include a current collector 100 and a first electrode active material layer 110. The electrode 10 may further include a second electrode active material layer 140. The electrode 10 may be a positive electrode or a negative electrode.

[0031] The current collector 100 can be formed from a metal foil having a predetermined width, a predetermined length, and a thickness of 5 to 20 μm.

[0032] The current collector 100 may be formed of one or more metal materials selected from the group consisting of aluminum, stainless steel, nickel, titanium, and copper.

[0033] The first electrode active material layer 110 may be coated on one surface of the current collector 100 .

[0034] The first electrode active material layer 110 may include a compressed portion 111, which is a region where a predetermined region is compressed by applying pressure, and an uncompressed portion 113, which is a region where no pressure is applied.

[0035] The compressed portion 111 may be formed at an end of the first electrode active material layer 110. The compressed portion 111 may be formed in a region adjacent to a cut surface when the current collector 100 coated with the first electrode active material layer 110 and the second electrode active material layer 140 is cut using the electrode cutting device 30. More specifically, the compressed portion 111 may be formed on one side of the cut surface.

[0036] The compressed portion 111 is formed by compressing a predetermined region of the first electrode active material layer 110 coated on the current collector 100, thereby improving the adhesion between the current collector 100. When cutting the current collector 100 coated with the first electrode active material layer 110, an external force is applied inward by the cutting blade to the coated first electrode active material layer 110, weakening the adhesion between the first electrode active material layer 110 and the current collector 100, which may cause a problem in that the end of the first electrode active material layer 110 is peeled off from the current collector 100. Therefore, by applying pressure to the end of the first electrode active material layer 110 coated on the current collector 100 to form the compressed portion 111, the adhesion between the first electrode active material layer 110 and the current collector 100 can be improved.

[0037] The compressed portion 111 is compressed by applying pressure to the electrode 10 by a cutting device, and therefore can be formed to have a higher density than the non-compressed portion 113 located in the inner region of the compressed portion 111 .

[0038] The non-compressed portion 113 may be located in an inner region of the compressed portion 111 in the first active material layer and may be a region that is not pressurized by the electrode cutting device 30. The non-compressed portion 113 may be formed to have a lower density than the compressed portion 111.

[0039] The ends of the compressed portions 111 are cut together with the current collector 100 by the electrode cutting device 30, and therefore may be formed to coincide with the ends of the current collector 100. By forming the ends of the compressed portions 111 to coincide with the ends of the current collector 100, it is possible to minimize the proportion of uncoated portions, which are areas not coated with the first electrode active material layer 110, and increase the proportion of ground portions, which are coated with the first electrode active material layer 110. Increasing the proportion of ground portions, which essentially generate electrical energy through a chemical reaction, can improve the energy density of the electrode assembly 20 and secondary battery of the same volume.

[0040] The upper surface of the compressed portion 111 may be formed as a continuous inclined surface 112 facing the current collector 100. The inclined surface 112 formed on the compressed portion 111 may be formed in a downward direction toward the end of the current collector 100.

[0041] The compressed portion 111 may have a density that increases toward the edge because the electrode cutting device 30 applies stronger pressure toward the edge. Since the edge is the region where the first electrode active material layer 110 begins to peel off from the current collector 100, the edge of the compressed portion 111 may be formed to have the highest density, thereby allowing the edge of the first electrode active material layer 110 to have the strongest adhesion to the current collector 100.

[0042] The inclined surface 112 can prevent the separator 210, which contacts one side of the electrode 10, from being damaged, such as being broken, due to a step caused by the thickness of the electrode 10 when manufacturing the electrode assembly 20 including the electrode 10, and can disperse and cushion the impact applied to the separator 210 due to contact with the end of the electrode 10.

[0043] The inclined surface 112 formed on the upper surface of the compression portion 111 may be formed as a flat surface.

[0044] The electrode 10 may further include a second electrode active material layer 140 coated on the other surface of the current collector 100 .

[0045] The second electrode active material layer 140 may contain the same material as the first electrode active material layer 110 .

[0046] The second electrode active material layer 140 is not positioned in an area facing the electrode cutting device 30, and is therefore not directly pressed by the electrode cutting device 30. As a result, the second electrode active material layer 140 can be formed asymmetrically with respect to the first electrode active material layer 110 with respect to the current collector 100.

[0047] The edge of the second electrode active material layer 140 is cut together with the current collector 100 by the electrode cutting device 30, and therefore may be formed to coincide with the edge of the current collector 100. By forming the edge of the second electrode active material layer 140 to coincide with the edge of the current collector 100, the proportion of uncoated portions can be minimized and the proportion of ground portions coated with the first electrode active material layer 110 can be increased. Increasing the proportion of ground portions that generate electrical energy substantially through a chemical reaction can improve the energy density of the electrode assembly 20 and secondary battery of the same volume.

[0048] Second embodiment Referring to Fig. 3, in a second embodiment of the present invention, an electrode 11 may include a current collector 100 and a first electrode active material layer 120. The electrode 11 may further include a second electrode active material layer 140. The electrode 11 may be a positive electrode or a negative electrode.

[0049] The current collector 100 can be formed from a metal foil having a predetermined width, a predetermined length, and a thickness of 5 to 20 μm.

[0050] The current collector 100 may be formed of one or more metal materials selected from the group consisting of aluminum, stainless steel, nickel, titanium, and copper.

[0051] The first electrode active material layer 120 may be coated on one surface of the current collector 100 .

[0052] The first active material layer can include compressed portions 121, which are regions where predetermined regions are compressed by applying pressure, and non-compressed portions 122, which are regions where no pressure is applied.

[0053] The compressed portion 121 may be formed at an end of the first electrode active material layer 120. The compressed portion 121 may be formed in a region adjacent to a cut surface when the current collector 100 coated with the first electrode active material layer 120 and the second electrode active material layer 140 is cut by the electrode cutting device 31. More specifically, the compressed portion 121 may be formed on one side of the cut surface.

[0054] The compressed portion 121 can be configured to improve adhesion to the current collector 100 because a predetermined region of the first electrode active material layer 120 coated on the current collector 100 is pressurized and compressed. When cutting the current collector 100 coated with the first electrode active material layer 120, an external force is applied inward by the cutting blade to the coated electrode active material, weakening the adhesion between the first electrode active material layer 120 and the current collector 100, which can cause a problem of the end of the first electrode active material layer 120 peeling off from the current collector 100. Therefore, by pressurizing the end of the first electrode active material layer 120 coated on the current collector 100 to form the compressed portion 121, the adhesion between the first electrode active material layer 120 and the current collector 100 can be improved.

[0055] The compressed portion 121 is compressed by the electrode cutting device 31 and therefore can be formed with a higher density than the non-compressed portion 122 located in the inner region of the compressed portion 121 .

[0056] The non-compressed portion 122 may be located in an area inside the compressed portion 121 in the first electrode active material layer 120 and may be an area that is not compressed by the electrode cutting device 31. The non-compressed portion 122 may be formed to have a lower density than the compressed portion 121.

[0057] The ends of the compressed portions 121 are cut together with the current collector 100 by the electrode cutting device 31, and therefore may be formed to coincide with the ends of the current collector 100. By forming the ends of the compressed portions 121 to coincide with the ends of the current collector 100, it is possible to minimize the proportion of uncoated portions, which are areas not coated with the active material of the electrode 11, and increase the proportion of ground portions, which are coated with the active material of the electrode 11. Increasing the proportion of ground portions, which essentially generate electrical energy through a chemical reaction, can improve the energy density of the electrode assembly 20 of the same volume and the secondary battery in which the electrode assembly 20 is housed.

[0058] The compressed portion 121 may be formed with a slope such that the height of the upper surface thereof gradually decreases toward the end of the current collector 100. The compressed portion 121 may be formed in a stepped shape with the height decreasing toward the end.

[0059] The compression section 121 can include a first section 121a, a second section 121b, and a third section 121c.

[0060] The first portion 121a forms an end of the compressed portion 121 when the first electrode active material layer 120 is cut by the cutter 300 of the electrode cutting device 31, and may be formed in a direction perpendicular to one surface of the current collector 100, which is the cutting direction.

[0061] The first part 121a forms a cut surface of the first electrode active material layer 120 cut by the cutter 300 of the electrode cutting device 31, and can be formed flush with the edge of the current collector 100 so as to coincide with the edge of the current collector 100.

[0062] The upper end of the first portion 121a can be in vertical contact with one end of the third portion 121c to form an intersection.

[0063] The second portion 121b may be spaced a predetermined distance from the first portion 121a along the inclined direction formed in the compressed portion 121 and may be formed in a direction perpendicular to one surface of the current collector 100. The second portion 121b may be located at a height higher than the first portion 121a.

[0064] The upper end of the second portion 121b can contact one end of the non-compressed portion 122 to form an intersection.

[0065] The intersections may be formed in a region where the first portion 121a and the third portion 121c contact each other and in a region where the second portion 121b and the non-compressed portion 122 contact each other. The intersections may form inclinations where the height intermittently decreases or increases along the inclination direction formed in the compressed portion 121. The intersections are regions that come into contact with the separator 210 when at least one of the electrode 11 and the separator 210 is stacked and wound to manufacture the electrode assembly 20. The intersections increase the contact area with the separator 210 to distribute the force and gradually change the angle of the separator 210, thereby preventing the separator 210 from being broken and damaged by steps caused by the thickness of the electrode 11.

[0066] The third portion 121c may be formed between the first portion 121a and the second portion 121b in a direction perpendicular to the second portion 121b.

[0067] The third portion 121c may be formed by compressing the first electrode active material layer 120 by the compressing unit 320 of the electrode cutting device 31. Because the compressing region of the compressing unit 320 is compressed, the third portion 121c may form a step in the downward direction relative to the uncompressed portion 122. The second portion 121b may form a step between the uncompressed portion 122 and the third portion, and may form an intermittent slope by intermittently decreasing the height of the first electrode active material layer 120 toward the end.

[0068] The third portion 121c may be formed by pressing the first electrode active material layer 120 by the pressing unit 320 of the electrode cutting device 31. Because the third portion 121c is pressed by the pressing unit 320, the electrode active material coated on the current collector 100 is compressed, increasing the density and improving the adhesion to the current collector 100. This prevents the first electrode active material layer 120 from peeling off from the current collector 100 due to external impact, chemical reaction, etc.

[0069] The electrode 11 may further include a second electrode active material layer 140 coated on the other surface of the current collector 100 .

[0070] The description of the second electrode active material layer 140 is based on the description of the first embodiment.

[0071] Third embodiment Referring to Fig. 4, in a third embodiment of the present invention, an electrode 12 may include a current collector 100 and a first electrode active material layer 130. The electrode 12 may further include a second electrode active material layer 140. The electrode 12 may be a positive electrode or a negative electrode.

[0072] The current collector 100 can be formed from a metal foil having a predetermined width, a predetermined length, and a thickness of 5 to 20 μm.

[0073] The current collector 100 may be formed of one or more metal materials selected from the group consisting of aluminum, stainless steel, nickel, titanium, and copper.

[0074] The first electrode active material layer 130 may be coated on one surface of the current collector 100 .

[0075] The first electrode active material layer 130 may include a compressed portion 131, which is a region where a predetermined region is compressed by applying pressure, and an uncompressed portion 132, which is a region where no pressure is applied.

[0076] The compressed portion 131 may be formed at an end of the first active material layer. The compressed portion 131 may be formed in a region adjacent to a cut surface when the current collector 100 coated with the first electrode active material layer 130 and the second electrode active material layer 140 is cut using the electrode cutting device 32. More specifically, the compressed portion 131 may be formed on one side of the cut surface.

[0077] The compressed portion 131 can be configured to improve adhesion to the current collector 100 because the end of the first electrode active material layer 130 coated on the current collector 100 is compressed by pressure. When cutting the current collector 100 coated with the active material for the electrode 12, an external force is applied inward by the cutting blade to the coated active material for the electrode 12, weakening the adhesion between the active material for the electrode 12 and the current collector 100, which can cause the end of the active material for the electrode 12 to peel off from the current collector 100. Therefore, by forming the compressed portion 131 by pressurizing the end of the first electrode active material layer 130 coated on the current collector 100, the adhesion between the first electrode active material layer 130 and the current collector 100 can be improved.

[0078] The compressed portion 131 is compressed by the electrode cutting device 32 and therefore can be formed with a higher density than the non-compressed portion 132 located in the inner region of the compressed portion 131 .

[0079] The non-compressed portion 132 may be located in an area inside the compressed portion 131 in the first electrode active material layer 130 and may be an area that is not compressed by the electrode cutting device 32. The non-compressed portion 132 may be formed to have a lower density than the compressed portion 131.

[0080] The ends of the compressed portions 131 are cut together with the current collector 100 by the electrode cutting device 32, and therefore may be formed to coincide with the ends of the current collector 100. By forming the ends of the compressed portions 131 to coincide with the ends of the current collector 100, it is possible to minimize the proportion of uncoated portions, which are areas not coated with the first electrode active material layer 130, and increase the proportion of ground portions, which are coated with the first electrode active material layer 130. Increasing the proportion of ground portions, which essentially generate electrical energy through a chemical reaction, can improve the energy density of the electrode assembly 20 of the same volume and the secondary battery in which the electrode assembly 20 is housed.

[0081] The compressed portion 131 may be formed with a slope such that the height of the upper surface thereof gradually decreases toward the end of the current collector 100. The compressed portion 131 may be formed in a stepped shape with the height decreasing toward the end.

[0082] The compression section 131 can include a first section 131a, a second section 131b, and a third section 131c.

[0083] The first portion 131a forms an end of the compressed portion 131 by cutting the first electrode active material layer 130 by the cutter 300 of the electrode cutting device 32, and may be formed in a direction perpendicular to one surface of the current collector 100, which is the cutting direction.

[0084] The first part 131a forms a cut surface formed when the first electrode active material layer 130 is cut by the cutter 300 of the electrode cutting device 32, and may be formed flush with the edge of the current collector 100 so as to coincide with the edge of the current collector 100.

[0085] The upper end of the first portion 131a can be in vertical contact with one end of the third portion 131c to form an intersection.

[0086] The second portion 131b may be spaced a predetermined distance from the first portion 131a along the inclined direction formed in the compressed portion 131 and may be formed in a direction perpendicular to one surface of the current collector 100. The second portion 131b may be located at a height higher than the first portion 131a.

[0087] The upper end of the second portion 131b can contact one end of the non-compressed portion 132 to form an intersection.

[0088] The intersections may be formed in a region where the first portion 131a and the third portion 131c contact each other and in a region where the second portion 131b and the non-compressed portion 132 contact each other. The intersections may form inclinations where the height intermittently decreases or increases along the inclination direction formed in the compressed portion 131. The intersections are regions that come into contact with the separator 210 when at least one of the electrode 12 and the separator 210 is stacked and wound to manufacture the electrode assembly 20. The intersections increase the contact area with the separator 210 to distribute the force and gradually change the angle of the separator 210, thereby preventing the separator 210 from being broken and damaged by steps caused by the thickness of the electrode 12.

[0089] The third portion 131c may be formed between the first portion 131a and the second portion 131b in a direction perpendicular to the second portion 131b.

[0090] The third portion 131c may be formed by applying pressure to the first electrode active material layer 130 by the pressure unit 320 of the electrode cutting device 32. Because the third portion 131c is compressed by the pressure applied by the pressure unit 320, a step may be formed in the downward direction toward the end of the non-compressed portion 132. The second portion 131b may form a step between the non-compressed portion 132 and the third portion 131c, and the height of the first electrode active material layer 130 may be intermittently reduced toward the end, forming an intermittent slope.

[0091] The third portion 131c may be formed by pressing the first electrode active material layer 130 by the pressing unit 320 of the electrode cutting device 32. Because the third portion 131c is pressed by the pressing unit 320, the first electrode active material layer 130 coated on the current collector 100 is compressed, increasing the density and improving the adhesion to the current collector 100. This prevents the first electrode active material layer 130 from peeling off from the current collector 100 due to external impact, chemical reaction, etc.

[0092] The second portion 131b and the third portion 131c may each be provided in plural. The compression portion 131 may have a plurality of steps formed in sequence along the inclination direction, and may be formed in a staircase shape formed in sequence along the inclination direction.

[0093] The plurality of second portions 131b may be formed spaced apart from one another at predetermined intervals along the inclination direction of the compressed portion 131. Therefore, the first portion 131a and the plurality of second portions 131b may be arranged in sequence along the inclination direction of the compressed portion 131.

[0094] The plurality of third portions 131c may be disposed between the first portion 131a and the second portion 131b and between the plurality of second portions 131b. More specifically, the third portion 131c may connect the upper end of the first portion 131a to the lower end of the second portion 131b, and may connect the upper end of the second portion 131b to the lower end of the adjacent second portion 131b.

[0095] The plurality of third portions 131c may be formed to have heights that decrease sequentially toward the ends depending on the degree to which the active material of the electrode 12 is compressed. The degree to which the first electrode active material layer 130 is compressed increases toward the ends of the compressed portions 131, and the heights of the plurality of third portions 131c may intermittently decrease toward the ends of the compressed portions 131. That is, the third portion 131c located at the forefront of the plurality of third portions 131c may have the highest density and the strongest adhesion to the current collector 100 because the degree to which the active material of the electrode 12 is compressed is the greatest.

[0096] The plurality of third portions 131c may form intersections in regions where they contact the first portion 131a and the plurality of second portions 131b. The intersections formed by the plurality of third portions 131c contacting the first portion 131a and the plurality of second portions 131b may be arranged in order along the inclination direction of the compressed portion 131. The intersections may contact one side of the separator 210 in the electrode assembly 20 formed by stacking and winding the electrode 12 and the separator 210. The intersections increase the contact area with one side of the separator 210, dispersing force and cushioning impacts that may be applied to the separator 210.

[0097] In addition, since the multiple intersections are arranged in sequence along the inclination direction of the compression section 131 to form an incline, the angle at which the separator 210 bends when it comes into contact with the end of the electrode 12 is reduced, and the separator 210 can be prevented from being broken and damaged due to a height difference caused by the thickness of the end of the electrode 12.

[0098] The electrode 12 may further include a second electrode active material layer 140 coated on the other surface of the current collector 100 .

[0099] The description of the second electrode active material layer 140 is based on the description of the first embodiment.

[0100] Fourth embodiment Referring to FIGS. 5 and 6, in a fourth embodiment of the present invention, an electrode assembly 20 is formed by stacking and winding at least one of separators 210 and 220 and electrodes 10, 11, and 12, and may include a core 200 formed at the center around which the separators 210 and 220 and the electrodes 10, 11, and 12 are wound.

[0101] The core 200 may refer to an empty space formed along the central axis around which the separators 210, 220 and the electrodes 10, 11, and 12 are wound in the electrode assembly 20. The electrode assembly 20 may be formed in a shape in which at least one or more separators 210, 220 and at least one or more electrodes 10, 11, and 12 surround the core 200 at the center.

[0102] Referring to FIG. 6 , the core 200 may be formed at the center of the winding around which at least one of the electrodes 10, 11, and 12 and the separators 210 and 220 are wound. The wound electrodes 10, 11, and 12 may be arranged to contact the separator 210 located inside the electrodes 10, 11, and 12. More specifically, the first electrode active material layers 110, 120, and 130 may be arranged to contact the separator 210 located inside the electrodes 10, 11, and 12. Because the separator 210 is formed longer than the electrodes 10, 11, and 12, the ends of the separator 210 may extend longer than the ends of the electrodes 10, 11, and 12. Compressed portions 111, 121, and 131 are formed at the ends of the first electrode active material layers 110, 120, and 130, and the compressed portions 111, 121, and 131 are sloped downward toward the ends. As a result, the separator 210 can be guided so that the angle gradually changes along the length direction without being suddenly bent by contacting the slopes formed on the compressed portions 111, 121, and 131.

[0103] In addition, the inclination of the ends of the electrodes 10, 11, and 12 can increase the contact area with the separator 210, thereby cushioning the impact that the separator 210 receives from the electrodes 10, 11, and 12 due to external or internal impact.

[0104] The cross-sectional shape of the electrode assembly 20 may be formed in various ways depending on the structure in which the separators 210, 220 and the electrodes 10, 11, 12 are wound, and may be, for example, a circle, an oval, a rectangle, etc., but is not limited thereto.

[0105] For a detailed description of the electrodes 10, 11, and 12 included in the electrode assembly 20, the contents of the first to third embodiments described above are cited.

[0106] Fifth embodiment Referring to FIG. 7, as a fifth embodiment of the present invention, an electrode cutting device 30 for an electrode 10 may include a cutter 300 and a pressure unit 310.

[0107] The electrode cutting device 30 may be a device that cuts the current collector 100 coated with the first electrode active material layer 110 into a predetermined size and applies pressure to the end of the first electrode active material layer 110 coated on the current collector 100.

[0108] The cutter 300 may be provided to cut the current collector 100 coated with the first electrode active material layer 110 .

[0109] The cutter 300 is arranged so that its end faces the current collector 100 coated with the first electrode active material layer 110, and can be driven in a direction toward or away from the current collector 100 coated with the first electrode active material layer 110.

[0110] The cutter 300 may be disposed such that its width direction is perpendicular to one surface of the current collector 100 and its length direction is along the width direction of the current collector 100 .

[0111] The cutter 300 can be formed so that its ends are gradually thinner toward the ends.

[0112] The pressure member 310 may be formed to protrude from one side or both sides of the cutter 300 .

[0113] The pressure unit 310 is formed to protrude from the cutter 300, and is driven together with the cutter 300, so that when the cutter 300 cuts the electrode 10, the pressure unit 310 can be provided to apply pressure to the end of the cut electrode 10.

[0114] By the pressing unit 310 pressing the end of the cut electrode 10, the first electrode active material layer 110 coated on the current collector 100 can be compressed, and the adhesion between the first electrode active material layer 110 and the current collector 100 can be improved.

[0115] The pressure unit 310 may include an inclined pressure surface 311 that is continuously inclined so as to become farther from one side or both sides of the cutter 300 as it becomes farther from the end of the cutter 300 .

[0116] The inclined pressure surface 311 applies pressure to the end of the first electrode active material layer 110, thereby forming an inclined surface 112 having a shape corresponding to the inclined pressure surface 311 at the end of the first electrode active material layer 110.

[0117] The inclined pressing surface 311 can compress the end of the first electrode active material layer 110 by applying pressure to the end of the first electrode active material layer 110, and the closer the position is to the cutter 300, the stronger the pressure can be applied to the first electrode active material layer 110. In other words, the inclined pressing surface 311 applies the strongest pressure to the end of the first electrode active material layer 110, and therefore can be formed to maximize the adhesion between the end of the first electrode active material layer 110 and the current collector 100 so that the first electrode active material layer 110 is not peeled off from the current collector 100.

[0118] Sixth embodiment Referring to FIG. 8, as a sixth embodiment of the present invention, an electrode cutting device 31 can include a cutter 300 and a pressure unit 320.

[0119] The electrode cutting device 31 may be a device that cuts the current collector 100 coated with the first electrode active material layer 120 into a predetermined size and applies pressure to the end of the first electrode active material layer 120 coated on the current collector 100.

[0120] The cutter 300 may be provided to cut the current collector 100 coated with the first electrode active material layer 120 .

[0121] The cutter 300 is arranged so that its end faces the current collector 100 coated with the first electrode active material layer 120, and can be driven in a direction toward or away from the current collector 100 coated with the first electrode active material layer 120.

[0122] The cutter 300 may be disposed such that its width direction is perpendicular to one surface of the current collector 100 and its length direction is along the width direction of the current collector 100 .

[0123] The cutter 300 can be formed so that its ends are gradually thinner toward the ends.

[0124] When the first electrode active material layer 120 is cut by the cutter 300, a first portion 121a may be formed on the cut surface.

[0125] The pressure unit 320 may be formed to protrude from one or both sides of the cutter 300. When the pressure unit 320 is formed on both sides of the cutter 300, it can apply pressure to the ends of each of the electrodes 11 cut into multiple pieces by the cutter 300. The cutter 300 moves linearly back and forth within a predetermined area, and referring to FIG. 1 , the electrode 11 continues to move in a direction perpendicular to the movement direction of the cutter 300 by a conveyor, moving means, etc., so that one end and the other end of the electrode 11 are cut by the cutter 300, and both end portions of the electrode 11 can be pressed by the pressure unit 320.

[0126] The pressure member 320 is formed to protrude from one or both sides of the cutter 300, and is driven and moved together with the cutter 300. When the cutter 300 cuts the electrode 11, the pressure member 320 can apply pressure to the end of the cut electrode 11.

[0127] By the pressing unit 320 pressing the end of the cut electrode 11, the first electrode active material layer 120 coated on the current collector 100 can be compressed, and the adhesion between the first electrode active material layer 120 and the current collector 100 can be improved.

[0128] The pressure unit 320 may include a pressure surface that is inclined so that the protruding height increases intermittently as it goes away from the end of the cutter 300. That is, the pressure unit 320 may include a stepped shape.

[0129] The pressure surfaces may include a first pressure surface 321 and a second pressure surface 322 .

[0130] A plurality of first pressing surfaces 321 may be provided, and the plurality of first pressing surfaces 321 may be spaced apart from each other by a predetermined distance along the inclination direction of the pressing surfaces.

[0131] The first pressure surface 321 may be formed in a direction perpendicular to one side of the cutter 300 and may be disposed so as to face the electrode 11 to be cut by the cutter 300 .

[0132] The first pressing surface 321 can pressurize the end of the first electrode active material layer 120 when the cutter 300 cuts the electrode 11. Among the plurality of first pressing surfaces 321, the first pressing surface 321 formed closest to the cutter 300 presses the first electrode active material layer 120 most strongly, so that the end of the first electrode active material layer 120 positioned closest to the cutter 300 can be formed with the highest density and can have the strongest adhesion to the current collector 100.

[0133] The first pressure surface 321 can pressurize the end portion of the first electrode active material layer 120 to form the third portion 121c.

[0134] The second pressing surfaces 322 may be formed between the plurality of first pressing surfaces 321 and may be formed in a direction perpendicular to the first pressing surfaces 321. The second pressing surfaces 322 may form step-like differences between the plurality of first pressing surfaces 321.

[0135] The second pressure surface 322 can pressurize the end of the first electrode active material layer 120 to form the second portion 121b.

[0136] Seventh embodiment Referring to FIG. 9, as a seventh embodiment of the present invention, an electrode 12 and an electrode cutting device 32 may include a cutter 300 and a pressure unit 330 .

[0137] The electrode cutting device 32 may be a device that cuts the current collector 100 coated with the first electrode active material layer 130 into a predetermined size and applies pressure to the end of the first electrode active material layer 130 coated on the current collector 100.

[0138] The cutter 300 may be provided to cut the current collector 100 coated with the first electrode active material layer 130 .

[0139] The cutter 300 is positioned so that its end faces the current collector 100 coated with the first electrode active material layer 130, and can be driven in a direction toward or away from the current collector 100 coated with the first electrode active material layer 130.

[0140] The cutter 300 may be disposed such that its width direction is perpendicular to one surface of the current collector 100 and its length direction is along the width direction of the current collector 100 .

[0141] The cutter 300 can be formed so that its ends are gradually thinner toward the ends.

[0142] When the first electrode active material layer 130 is cut by the cutter 300, a first portion 131a may be formed on the cut surface.

[0143] The pressure unit 330 may be formed to protrude from one or both sides of the cutter 300. When the pressure unit 330 is formed on both sides of the cutter 300, it can apply pressure to the ends of each of the electrodes 12 cut into multiple pieces by the cutter 300. Referring to FIG. 1 , the cutter 300 moves linearly back and forth within a predetermined area, and the electrode 12 continues to move in a direction perpendicular to the movement direction of the cutter 300 by a conveyor, moving means, etc., so that one end and the other end of the electrode 12 are cut by the cutter 300, and both side ends of the electrode 12 are pressed by the pressure unit 330, thereby forming the compressed portions 131.

[0144] The pressure member 330 is formed to protrude from one side or both sides of the cutter 300, and is driven and moved together with the cutter 300. When the cutter 300 cuts the electrode 12, the pressure member 330 can apply pressure to the end of the cut electrode 12.

[0145] By the pressing unit 330 pressing the end of the cut electrode 12, the first electrode active material layer 130 coated on the current collector 100 can be compressed, and the adhesion between the first electrode active material layer 130 and the current collector 100 can be improved.

[0146] The pressure unit 330 may include a pressure surface that is inclined so that the protruding height increases intermittently as it goes away from the end of the cutter 300. That is, the pressure unit 330 may be formed in a stepped shape.

[0147] The pressure surfaces may include a first pressure surface 331 and a second pressure surface 332 .

[0148] A plurality of first pressing surfaces 331 may be provided, and the plurality of first pressing surfaces 331 may be spaced apart from each other by a predetermined distance along the inclination direction of the inclined pressing surface.

[0149] The first pressure surface 331 may be formed in a direction perpendicular to one side of the cutter 300 and may be disposed so as to face the electrode 12 to be cut by the cutter 300 .

[0150] The first pressing surface 331 can pressurize the end of the first electrode active material layer 130 when the cutter 300 cuts the electrode 12. Among the plurality of first pressing surfaces 331, the first pressing surface 331 formed closest to the cutter 300 presses the first electrode active material layer 130 most strongly, so that the first electrode active material layer 130 positioned closest to the cutter 300 can be formed with the highest density and the strongest adhesion to the current collector 100.

[0151] The first pressure surface 331 can pressurize the end of the first electrode active material layer 130 to form the third portion 131c.

[0152] The second pressing surfaces 332 may be formed between the plurality of first pressing surfaces 331 and may be formed in a direction perpendicular to the first pressing surfaces 331. The second pressing surfaces 332 may form step-like differences between the plurality of first pressing surfaces 331.

[0153] The second pressure surface 332 can pressurize the end of the first electrode active material layer 130 to form the second portion 131b.

[0154] A plurality of second pressing surfaces 332 may be provided, and the plurality of second pressing surfaces 332 may be formed to connect the plurality of first pressing surfaces 331 to each other.

[0155] The plurality of second pressure surfaces 332 may be arranged at predetermined intervals along the slope of the inclined pressure surface.

[0156] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the technical spirit of the present invention and the scope of equivalents of the appended claims by a person having ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0157] 10, 11, 12 electrodes 20 Electrode assembly 30, 31, 32 Electrode cutting device 100 Current collector 110, 120, 130 1st electrode active material layer 111, 121, 131 Compression section 112 Slope 113, 122, 132 Uncompressed section 121a, 131a Part 1 121b, 131b Part 2 121c, 131c Part 3 140 Second electrode active material layer 200 cores 210, 220 separator 300 cutters 310, 320, 330 Pressurizing section 311 Inclined pressure surface 321, 331 First pressure surface 322, 332 Second pressure surface

Claims

1. a current collector formed of a metal foil; a first electrode active material layer coated on one surface of the current collector, the first electrode active material layer having a compressed portion formed by compressing a predetermined region; a second electrode active material layer coated on the other surface of the current collector, The compression section formed on an end of the first electrode active material layer, An electrode formed with a higher density than a region located inside the compressed portion.

2. The electrode of claim 1 , wherein an end of the compressed portion coincides with an end of the current collector.

3. The electrode of claim 2 , wherein the second electrode active material layer is formed asymmetrically with respect to the first electrode active material layer with respect to the current collector.

4. The electrode according to claim 1 , wherein the compressed portion has an upper surface formed as a continuous inclined surface facing the current collector.

5. The electrode according to claim 1 , wherein the compressed portion has an upper surface that is inclined so that its height gradually decreases toward the current collector as it approaches the end.

6. The compression section a first portion that forms an end of the compressed portion and is formed in a direction perpendicular to one surface of the current collector; a second portion that is spaced a predetermined distance from the first portion along the inclination direction and that is formed in a direction perpendicular to one surface of the current collector; The electrode according to claim 5 , further comprising: a third portion connecting the first portion and the second portion and formed in a direction perpendicular to the second portion.

7. a plurality of the second and third parts are provided; the plurality of second portions are formed spaced apart from one another along the inclination direction, The electrode according to claim 6 , wherein the plurality of third portions are formed to connect the first portion and the second portion, and to connect the plurality of second portions to each other.

8. The compression section The electrode according to claim 7 , further comprising a plurality of fourth portions protruding outward in a region where the first portion and the third portion meet and in a region where the second portion and the third portion meet.

9. An electrode assembly in which at least one of a separator and an electrode is stacked and wound, a core formed at the center by winding the separator and the electrodes; The electrode is A current collector; a first electrode active material layer coated on one surface of the current collector, the first electrode active material layer having a compressed portion formed by compressing a predetermined region of the first electrode active material layer; The compression section the first electrode active material layer is formed on an end portion of the first electrode active material layer and is arranged to face the core so that the separator can cover the first electrode active material layer; The first electrode active material layer has a higher density than an inner region of the compressed portion along a winding direction of the first electrode active material layer.

10. The electrode assembly according to claim 9 , wherein an upper surface of the compressed portion is formed as a continuous inclined surface facing the current collector.

11. The electrode assembly according to claim 9 , wherein the compressed portion has an inclination such that the height of the upper surface of the compressed portion gradually decreases toward the current collector as it approaches the end.

12. a cutter provided to cut the current collector coated with the electrode active material; and a pressure unit that protrudes from both sides of the cutter at a position spaced apart from the end of the cutter and applies pressure to one side of the cut surface cut by the cutter to increase the density of the electrode active material.

13. The electrode cutting device according to claim 12 , wherein the pressure unit includes an inclined pressure surface that is continuously inclined so as to become farther from both side surfaces of the cutter as it becomes farther from the end of the cutter.

14. The electrode cutting device according to claim 12 , wherein the pressure unit includes an inclined pressure surface that is inclined so that the protruding height increases intermittently with increasing distance from the end of the cutter.

15. The inclined pressure surface is a first pressure surface formed to face the cutting direction of the cutter; The electrode cutting device according to claim 14 , further comprising: a second pressure surface extending from an end of the first pressure surface in a direction perpendicular to the first pressure surface.

16. The first pressure surface is provided in a plurality of pieces, The electrode cutting device according to claim 15, wherein the plurality of first pressure surfaces are spaced apart from one another along the inclined pressure surface.

17. The second pressure surface is provided in a plurality of pieces, The electrode cutting device according to claim 16, wherein the plurality of second pressure surfaces are arranged at each end of the plurality of first pressure surfaces along the inclined direction of the inclined pressure surface.

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