Electrode assembly, cylindrical battery cell, battery cell cutting device, and battery pack and vehicle including the same

Abstract

An electrode assembly, a battery cell, a battery cell cutting apparatus, a battery pack, and a vehicle incorporating them are disclosed. The present invention provides an electrode assembly (110) comprising: an electrode cell body portion (111) in which a separator (13) is stacked between a first electrode sheet (11) and a second electrode sheet (12), which are sheet-shaped, and the first electrode sheet (11), the second electrode sheet (12), and the separator (13) are coiled, and an uncoated portion (15) not coated with a layer of active material is formed at the ends across the width of the first electrode sheet (11) and the second electrode sheet (12);a plurality of cut surface portions (115) formed by cutting a portion of the uncoated portion (15) in a circumferential direction around a central portion (112) of the electrode cell body portion (111); and a plurality of forming portions (117) arranged between the cut surface portions (115) and formed by pressing and placing uncut portions (117a) of the uncoated portion (15).;

Description

Electrode assembly, cylindrical battery cell, battery cell cutting device, and battery pack and vehicle including the same Technical field The present invention relates to a cutting device according to the preamble of claim 1 and to a method for manufacturing a battery cell according to the preamble of claim 7. An example of such a cutting device and of such a method is disclosed by document KR 20180116156. Background of the technique In general, a secondary battery includes a positive electrode, a negative electrode, and an electrolyte, and generates electrical energy using a chemical reaction. Secondary batteries, which have broad applicability due to their high energy density and range of electrical characteristics, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs), which are powered by an electrical drive system. A secondary battery of this type has the main advantage of significantly reducing the use of fossil fuels. It also has the advantage of generating no byproducts during energy consumption. Therefore, secondary batteries are attracting attention as a new energy source that can improve environmental friendliness and energy efficiency. The types of secondary batteries currently widely used include lithium-ion batteries, lithium-polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and similar types. The operating voltage of a single secondary battery cell, i.e., one 100-cell battery, is approximately 2.5 V to 4.5 V. Consequently, when a higher output voltage is required, multiple battery cells can be connected in series to form a battery pack. Furthermore, depending on the required charge / discharge capacity of the battery pack, multiple 100-cell battery cells can be connected in parallel. Therefore, the number and type of electrical connection of the battery cells within the battery pack can be configured in various ways, depending on the required output voltage or charge / discharge capacity. On the other hand, the following are known as types of unitary secondary battery cells: cylindrical battery cells, prismatic battery cells, and pouch-type battery cells. In the case of the cylindrical battery cell, a separator, which is an insulator, is placed between a positive and a negative electrode. These electrodes are rolled up to form a Swiss roll-shaped electrode assembly, and this assembly is inserted into a battery can to form a battery. Additionally, a strip-shaped electrode tab can be connected to an uncoated portion of each of the positive and negative electrodes. The electrode tab electrically connects the electrode assembly to an externally exposed electrode terminal. For reference, a positive electrode terminal is a cap plate of a seal that seals an opening in the battery can, and a negative electrode terminal is the battery can itself.However, the conventional cylindrical battery cell with the aforementioned structure suffers from high resistance, significant heat generation, and low current collection efficiency because the current is concentrated in the strip-shaped electrode tab attached to the uncoated portion of the positive and / or negative electrodes. This means the cross-sectional area of ​​the electrode tab can decrease rapidly, potentially leading to current flow bottlenecks. In a small cylindrical battery cell with a form factor of 18650 or 21700, resistance and heat are not significant issues. However, when the form factor is increased for electric vehicles, a large amount of heat can be generated around the electrode flange during rapid charging, potentially leading to cell fire. To solve a problem of this type, a cylindrical battery cell (a so-called flangeless cylindrical battery cell) has been proposed that has a structure in which the current collection efficiency is improved by designing an uncoated portion of the positive electrode and an uncoated portion of the negative electrode that are to be located at the upper and lower ends of a set of gypsy arm-type electrodes, respectively, and welding current collector plates to these uncoated portions. Each of a first electrode sheet and a second electrode sheet has a structure in which an active material is applied to a sheet-shaped current collector, and includes an uncoated portion on a long side thereof along a winding direction. An electrode stack is manufactured by sequentially stacking the first and second electrode sheets together with two spacers and then winding the stack in one direction. In this case, the uncoated portions of the first and second electrode sheets are oriented in opposite directions. After winding, the uncoated portions of the first and second electrode sheets are folded toward a core. Subsequently, the uncoated portions are welded to the current-collecting plates. Because the separate electrode tabs do not couple to the uncoated portion of the positive electrode and the uncoated portion of the negative electrode, the current-collecting plates are connected to external electrode terminals, and a current path is formed to have a large cross-sectional area along one winding axis of the electrode assembly, there is the advantage that the resistance of a battery cell can be lowered. This is because resistance is inversely proportional to the cross-sectional area of ​​the path through which current flows. To improve the soldering properties of the uncoated portion and the current collector plate in the flangeless cylindrical battery cell, the uncoated portion should be bent as flat as possible by applying strong pressure to a solder point of the uncoated portion. However, when the weld point of the uncoated portion is bent, the shape of the uncoated portion can become distorted and irregularly deformed. In this case, the deformed portion can come into contact with an electrode plate of opposite polarity, causing an internal short circuit or a hairline crack in the uncoated portion. Furthermore, as the uncoated portion adjacent to the electrode assembly core bends, it can block all or a significant portion of a cavity in the core. This creates a problem in the electrolyte injection process. Specifically, the cavity in the electrode assembly core A serves as a pathway through which electrolyte is injected. However, when this pathway is blocked, electrolyte injection becomes difficult.Additionally, an electrolyte injector can interfere with the uncoated portion near the core during the process of inserting it into the cavity, which can lead to a tearing problem of the uncoated portion. Furthermore, the folded portion of the uncoated section, to which the current collector plate is welded, should overlap in several layers and should not have any gaps (voids). This ensures sufficient weld strength and prevents a problem where the laser penetrates the electrode assembly and damages the separator or active material, even when using the latest technology, such as laser welding. Korean patent application publication no. 20-2022-0023100 (published on March 2, 2022, and retrievable as KR20220023100A) discloses a cylindrical secondary battery with an improved current-collecting structure. In this cylindrical secondary battery, a current-collecting plate is welded to an end portion of an uncoated portion in a state of linear contact. This results in a reduced cross-sectional area where the current-collecting plate and the uncoated portion are welded due to a gap between the plate and the uncoated portion. Consequently, the electrical resistance increases in the welded cross-sectional area, which is a current path, potentially increasing the amount of heating in the battery cell and the risk of ignition. Korean patent application publication no. 2016-0110610 (published on September 22, 2016, and retrievable as KR20160110610A) discloses a secondary battery and a cylindrical lithium secondary battery. The secondary battery is disclosed having a configuration in which a first collector plate is electrically connected to a first uncoated portion to be in direct contact with it, and a second current collector plate is electrically connected to a second uncoated portion to be in direct contact with it.This also presents the problem that the cross-sectional contact area between the current-collecting plate and the uncoated portion is reduced due to a gap between the current-collecting plate and the uncoated portion. This occurs because the first and second current-collecting plates are connected to end portions of the first and second uncoated portions in a state of linear contact with them, respectively. There is a limit to how much the cross-sectional contact area can be increased. Divulgation [Technical problem] The present invention is directed to providing a cutting device that allows a current path to be expanded by increasing the cross-sectional welding area of ​​an electrode assembly. The present invention is also directed to providing a cutting device, which allows inhibiting an increase in the amount of heating of the battery cell and reducing the possibility of ignition even when the electrode assembly is applied to a large capacity battery cell and a battery pack and vehicle that includes the battery cell. The present invention also relates to a cutting device, which allows preventing a boundary portion of a forming portion and a cutting surface portion from tearing or distorting and becoming irregularly deformed. The present invention also aims to provide a cutting device that reduces the amount of heating of the battery cell or significantly reduces the possibility of an explosion. The objects of the present invention are not limited to those described above, and other objects and advantages of the present invention will be understood from the following description and more definitively through embodiments of the present invention. It should also be readily understood that the objectives and advantages of the present invention can be realized and achieved by means and combinations thereof described in the appended claims. [Technical solution] To achieve the objects described above, the present invention can be applied to an electrode assembly that includes a Swiss roll-shaped electrode cell body portion in which a first electrode sheet and a second electrode sheet having different polarities are stacked and wound, and a separator for insulation between them. The stacking of the sheets can be done in the order of the first electrode sheet, the separator, the second electrode sheet and the separator. The winding can be performed along the longitudinal direction of the stacked sheets. Therefore, a length of the gypsy-arm shaped electrode cell body portion in an axial direction can correspond to a width of the stacked sheets. An uncoated portion, not covered with a layer of active material, is located at an end portion of at least one of the first and second electrode sheets in the width direction. Consequently, the uncoated portion is located at an end portion of the electrode cell body in the axial direction. The uncoated portion may be located at a lateral end portion of the electrode cell body in the axial direction, or it may be located at both lateral end portions of the electrode cell body in the axial direction. The uncoated portion of the electrode cell body portion of the electrode assembly includes a plurality of cut surface portions formed by trimming a portion of the uncoated portion. A portion of the uncoated portion remaining after trimming the previous portion constitutes an uncut portion. A plurality of shear surface portions are arranged along a circumferential direction around a core portion. The unsheared portion is located between two adjacent shear surface portions in the circumferential direction. The electrode assembly includes a plurality of forming portions created by performing a folding process on the uncut portion. The cut surface portions can be formed in a sector shape along the circumferential direction around the core portion of the electrode cell body portion. The cutting surface portion can have a center angle of 30° to 180°. More specifically, the cutting surface portion can have a center angle of 45° to 180° and, more preferably, a center angle of 60° to 120°. The cut surface portion can be formed by trimming a portion of the uncoated portion, which is separated outward a predetermined distance in the axial direction from a boundary portion of the uncoated portion and a coated portion. In other words, the cut surface portion can be referred to as trimming the uncoated portion from between the coated and uncoated portions. The forming portions can form radially around the core portion of the electrode cell body portion. The forming portion can be formed in a way that the uncut portion is bent radially from the electrode cell body portion and folded down. The uncut portion can be folded down toward the core portion. The forming portions can be formed in parallel with the radial direction of the electrode cell body portion. The electrode cell body portion can be formed in a cylindrical shape. The core portion can be formed in a hollow shape that passes through a central portion of the electrode cell body portion. To prevent the core portion from being blocked by the folded uncut portion when the uncut portion is folded down toward the core portion, a portion of the uncoated portion located near the core portion, between the core portion and an outer circumference of the electrode assembly, can be removed. This removal of the uncoated portion can be performed before the winding process. That is, the uncoated portion can be removed in a predetermined section adjacent to the core portion in a winding direction. When the stack of sheets is rolled up, removing the uncoated portion on the core side as described above, the uncoated portion near the core has already been removed before the cutting surface portion is formed. In other words, the uncut portion is not yet positioned on the core side. Consequently, the folded-out forming portion does not cover the core portion of the electrode assembly, even when the uncut portion is folded toward the core side. The present invention may provide a battery cell that includes the electrode assembly. The battery cell includes a battery can that houses the electrode assembly and is electrically connected to one of the first electrode sheet and the second electrode sheet to have a first polarity, a sealing cap portion configured to seal an open end of the battery can, and a first current collector plate electrically connected to the other of the first electrode sheet and the second electrode sheet to have a second polarity. The first current collector plate can be attached to the forming portion of the electrode assembly by welding or similar means to be electrically connected to it. One of the first electrode sheet and the second electrode sheet and the battery can be connected directly or can be connected through a second current collector plate. The battery can may include a support portion that projects inward radially from an inner circumference of the battery can. The support portion may support the sealing cap portion. The battery cell may also include an insulator to prevent a short circuit of different polarities. The insulator can be placed between the battery can and the sealing cap portion, isolating the battery can from the sealing cap portion. More specifically, the insulator can be placed between an outer circumferential surface of the sealing cap portion and an inner circumferential surface of the battery can, and between the support portion and the sealing cap portion. The insulator can be placed between the battery can and the first current collector plate, isolating the battery can from the first current collector plate. For example, the insulator can be placed between the first current collector plate and the support portion. The present invention may provide a battery pack that includes at least one battery cell described above. The present invention may provide a vehicle that includes at least one battery pack described above. The present invention provides a cutting device according to claim 1 configured to cut an uncoated portion provided in an end portion of an electrode cell body portion of the electrode assembly in an axial direction. The cutting device includes a first cutter portion configured to form first cutting lines in the uncoated portion in the axial direction of the electrode assembly while moving in the axial direction and a second cutter portion configured to form a second cutting line in the uncoated portion in a peripheral direction while moving in a radial direction of the electrode assembly. The second cutter portion forms the second cutting line to cut a partial section of the uncoated portion, which is rolled in a peripheral direction, and forms the cutting line in such a way that the second cutting line connects to the first cutting lines. As the first cut lines and the second cut line are connected, a portion of the uncoated portion surrounded by the first cut lines and the second cut line can be trimmed. The present invention may provide a processing device that includes the cutting device and a pressure portion configured to perform a bending process on the uncut portion remaining after the cutting operation has been performed by the cutting device. The pressure portion forms a forming portion by pressing and flattening the uncut portion of the uncoated portion. The uncut portion is pressed by the pressure portion in the radial direction and, consequently, the uncut portion is folded into a portion corresponding to the second cutting line and folded back in the radial direction. The first cutter portion may include a plurality of first blades arranged radially within the first cutter portion. The first blade extends in the axial direction and a blade edge can be formed on a front end portion of the blade in the axial direction. The first section of the cutter may also include a first section for generating vibrations. This first section of vibration generation may produce fine vibrations. The second cutter portion can be formed into a triangular shape to trim a portion of the uncoated portion to give a sector shape. Blade edges can be formed on two sides provided in a tip portion of the second cutter portion. The second cutter section may also include a second vibration generation section. This second vibration generation section may generate fine vibrations. The pressure portion can push the uncut portion of the uncoated portion down towards a core portion of the electrode cell body portion while moving in the radial direction (the radiation direction) of the electrode cell body portion. The present invention also provides a method according to claim 7, the method being a method for manufacturing the battery cell described above. The method for manufacturing the battery cell includes stacking a first electrode sheet, a second electrode sheet and a separator, and winding the stack to make an electrode assembly. Accordingly, the electrode assembly may include an electrode cell body portion in which the electrode sheets and separators are wound together. The electrode cell body portion may have a cylindrical shape. The electrode cell body portion may include a hollow core portion. A lateral end portion of at least one of the first and second electrode sheets, in a width direction, includes an uncoated portion that is not coated with a layer of active material. The uncoated portion extends along a longitudinal direction in an end portion of the first and / or second electrode sheets in a width direction. When both the first and second electrode sheets have the uncoated portion, the uncoated portion may be provided in each of the two lateral end portions in the width direction. Consequently, the uncoated portion can be provided at the end portion of the electrode cell body in an axial direction in a form that extends and protrudes in the axial direction. That is, the uncoated portion can be removed at a predetermined section adjacent to the core portion in a winding direction. The removal of the uncoated portion can be performed before the winding process after the electrode stack has been formed. This process can be carried out, for example, by laser processing. The removal of the uncoated portion may have already been carried out in the process of providing the electrode sheet before forming the electrode stack. The removal of the uncoated portion can also be performed after the electrode stack has been wound to form the electrode cell body. Such a process can be carried out, for example, using a cutter with ultrasonically vibrating blades. The method for manufacturing the battery cell includes removing a partial region of the uncoated portion provided on an end portion of the electrode cell body portion in the axial direction. Specifically, the removal of the uncoated portion includes cutting the uncoated portion, by a first cutter portion, to a predetermined depth in the axial direction while moving in the axial direction of the battery cell, and forming the first cutting lines in the axial direction in the uncoated portion. A plurality of first cutting lines may be provided. The plurality of first cutting lines may be arranged radially. Furthermore, the removal of the uncoated portion includes forming, by a second cutter portion, a second cutting line in the uncoated portion in a peripheral direction while moving radially inward from an outer circumference of the battery cell after forming the first cutting lines. A plurality of second cutting lines may be provided. The second cutting line may extend in the peripheral direction, and the plurality of second cutting lines may be aligned in the radial direction. The lengths of the plurality of second cutting lines in the peripheral direction can gradually increase from the core side towards the outer circumference in the radial direction. The second cutter portion trims the uncoated portion such that the second cutting line connects to two adjacent first cutting lines in the peripheral direction. Thus, a portion of the uncoated portion can be trimmed, which is surrounded by the second cutting line formed in the circumferential direction and a pair of first cutting lines connected respectively to both end portions of the second cutting line. The cut surface portions formed in a position from which the uncoated portion is trimmed can be formed in a sector shape along the circumferential direction around the core portion of the electrode cell body portion. The portion of the cutting surface can have a central angle of 60° to 120°. The method for manufacturing the battery cell may also include forming portions, which is an operation of bending and folding the uncut portion that remains after trimming the uncoated portion along the cutting lines in the radial direction. The bending process can be performed by pressing the uncut portion in the radial direction using a pressure portion. The forming portions can form radially around the core portion of the electrode cell body portion. The forming portion can be formed in a way in which the uncut portion of the uncoated portion folds down towards the core portion of the electrode cell body portion. The forming portion can form along the radial direction of the electrode cell body portion. The cut surface portion can be formed by cutting a portion of the uncoated portion, which is separated outwards a predetermined distance in the axial direction from the boundary portion of the uncoated portion and the coated portion. The first cutter portion can cut the uncoated portion by vibrating it using a first vibration generation portion. The first cutter portion can be an ultrasonic cutter. The second cutter portion can trim the uncoated portion by vibrating it using a second vibration-generating portion. The second cutter portion can be an ultrasonic cutter. [Advantageous effects] According to the present invention, after a planned cut portion and an uncut portion are separated from each other in the uncoated portion, the planned cut portion is trimmed to form a cut surface portion, and the uncut portion is pressed and folded to form a forming portion. Consequently, when the forming portion is formed by pressing the uncut portion, it is possible to prevent a boundary portion of the forming portion and the cut surface portion from tearing or distorting and becoming irregularly deformed. According to the present invention, because the boundary portion of the forming portion and the cutting surface portion are prevented from tearing or deforming, it is possible to prevent electrode sheets of opposite polarities from coming into contact with each other in the torn or deformed portion. According to the present invention, tearing or deformation of a boundary portion between the uncoated and coated portions is prevented when the uncoated portion is bent, thus preventing the detachment of an active material applied to the coated portion from the coated portion or the weakening of a bonding force. Consequently, a decrease in the performance and capacity of the battery cell can be inhibited. According to the present invention, delamination or damage to the edge of a separator due to a torn or deformed portion of the boundary can be prevented. Therefore, a short circuit between a first electrode sheet and a second electrode sheet can be avoided. Furthermore, the amount of heating of the battery cell can be reduced, or the possibility of an explosion can be significantly reduced. According to the present invention, because the cut surface portion is formed by trimming the uncoated portion extending axially in a region that does not constitute the forming portion, the length occupied by the uncoated portion in the axial direction at both ends of the electrode cell body portion can be reduced. Consequently, a volume of the electrode cell body portion, housed in a battery can, can be further secured in the axial direction. Therefore, it is possible to further increase the electrical capacity of a volume of the battery cell. In addition to the effects described above, specific effects of the present invention will be described along with the following detailed description for implementing the present invention. Description of the drawings Figure 1 is a plan view that schematically illustrates a stack of electrode cells according to the present invention. Figure 2 is a cross-sectional view of the electrode cell stack of Figure 1 taken along line AA. Figure 3 is a perspective view illustrating a state in which a portion of an electrode cell body is fabricated by winding the electrode cell stack of Figure 1. Figure 4 is a perspective view illustrating a state in which the electrode cell body portion according to the present invention is cut by a first cutter portion. Figure 5 is a perspective view illustrating the first cutter portion according to the present invention. Figure 6 is a rear view illustrating the first cutter portion according to the present invention. Figure 7 is a plan view illustrating a state in which an uncoated portion of the electrode cell body portion is trimmed by a second cutter portion according to the present invention. Figure 8 is a perspective view illustrating a state before the uncoated portion of the electrode cell body portion is trimmed by the second cutter portion according to the present invention. Figure 9 is a side view illustrating a state in which the second cutter portion according to the present invention trims the uncoated portion of the electrode cell body portion. Figure 10 is a perspective view illustrating a state in which a pressure portion presses an uncut portion in a state in which the second cutter portion according to the present invention has cut the uncoated portion of the electrode cell body portion. Figure 11 is a perspective view illustrating a state in which a forming portion is formed by pressing the uncut portion by means of the pressing portion according to the present invention. Figure 12 is a side view illustrating the state in which the forming portion is formed by pressing the uncut portion by means of the pressure portion according to the present invention. Figure 13 is a flowchart illustrating a method for manufacturing a battery cell according to the present invention. Figure 14 is a cross-sectional view illustrating an electrode assembly according to the present invention. Figure 15 is a perspective view illustrating a state in which the electrode assembly according to the present invention is housed in a package housing. Figure 16 is a perspective view illustrating a state in which a battery pack according to the present invention is installed in a vehicle. Description of reference numbers 10: electrode stack 11: first electrode sheet 12: second electrode sheet 13: separator 14: coated portion 15: uncoated portion 16: portion of border 16a: second cutting line 100: battery cell 101: Package accommodation 110: electrode assembly 111: Electrode cell body portion 112: portion of core 112a: portion removed from uncoated portion on core side, portion trimmed 113: first cutting line 115: portion of cutting surface 115a: planned cut portion 117: training portion 117a: uncut portion 120: battery can 121: portion of battery can body 122: support portion 123: clamping portion 130: first current collector plate 132: portion of central hole 140: second current collector plate 150: sealing cap portion 151: cover plate 152: external terminal 153: ventilation plate 155: driver portion 157: insulator 210: first portion of cutter 211: first blade 213: first portion of vibration generation 215: first portion of communication hole 220: second portion of cutter 221: second blade 223: second portion of vibration generation 230: pressure portion 300: vehicle Modes of invention Hereafter in this document, illustrative embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments disclosed below and is susceptible to various modifications and can be implemented in several different forms. The embodiments presented herein are arranged only to complete the disclosure of the present invention and to assist those skilled in the art to fully understand its scope. Accordingly, the present invention is not limited to the embodiments disclosed below, and it should be understood that the configurations of any one embodiment and the configurations of another embodiment are interchangeable or additive, and all modifications, equivalents, and substitutes fall within the spirit and technical scope of the present invention. In the drawings, the sizes or thicknesses of the components may be exaggerated for ease of understanding or similar reasons, but the scope of protection of the present invention should not be interpreted as being limited to this. The terms used herein are used only to describe a particular implementation or embodiment and are not intended to limit the present invention. Furthermore, singular forms are intended to include plural forms unless the context clearly indicates otherwise. In this specification, expressions such as "including," "comprising," and the like are intended to indicate the existence of features, numbers, operations, actions, components, parts, or combinations thereof disclosed herein. It should be understood that expressions such as "including," "comprising," and the like are not intended to exclude the possibility that other features, numbers, steps, actions, components, parts, or combinations thereof may be present or added. Although terms including ordinal numbers such as "first," "second," and the like can be used to describe various components, these components should not be limited by these terms. The terms are used only to distinguish one component from another. When it is said that one component "connects" to another, it should be understood that the component connects directly to the other component, or that another component may be interposed between them. On the other hand, when it is said that one component "connects directly" or "links directly" to another component, it should be understood that no other components are present between them. When it is said that a component is on a "top portion" or a "bottom portion" of another component, it should be understood that the component can be placed directly on top of another component, as well as that yet another component can be placed between them. Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning that would be commonly understood by a person skilled in the art to which the present invention pertains. It should be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless expressly defined as such herein. Hereafter in this document, an electrode assembly will be described in accordance with an embodiment of the present invention. For ease of description, in this specification, a direction along the longitudinal axis of a winding of an electrode array 110, wound in a Swiss roll shape, is referred to as the axial Y direction. Furthermore, a direction surrounding the winding axis is referred to as the circumferential X direction or peripheral direction. Additionally, a direction closer to or farther from the winding axis is referred to as the radial Z direction or radiation Z direction. Specifically, the direction closest to the winding axis is referred to as the centripetal direction, and the direction farthest from the winding axis is referred to as the centrifugal direction. Figure 1 is a plan view schematically illustrating an electrode cell stack according to the present invention, Figure 2 is a cross-sectional view of the electrode cell stack of Figure 1 taken along line AA, and Figure 3 is a perspective view illustrating a state in which an electrode cell body portion is manufactured by winding the electrode cell stack of Figure 1. Referring to Figures 1 to 3, an electrode stack 10 according to the embodiment of the present invention includes a first electrode sheet 11, a second electrode sheet 12, and a separator 13. The electrode stack 10 is formed by stacking the separator 13 between the first electrode sheet 11 and the second electrode sheet 12 in a leaf-like fashion. For example, the electrode stack 10 can be formed by stacking a first electrode sheet 11, a second electrode sheet 12, and two spacers 13. In addition, the electrode stack 10 can also be formed by stacking two or more first electrode sheets 11, two or more second electrode sheets 12, and three or more spacers 13. As the stacked number of first electrode sheets 11, second electrode sheets 12, and spacers 13 increases in the electrode stack 10, the winding time and the manufacturing time of the electrode assembly 110 having a desired diameter can be reduced. Each of the first electrode sheet 11 and the second electrode sheet 12 includes a coated portion 14, onto which an active material is applied as a coating, and an uncoated portion 15 that is not coated with the active material. The uncoated portion 15 can be formed on one side of each of the first electrode sheet 11 and the second electrode sheet 12 in a width direction. At least a portion of the uncoated portion 15 can be used as an electrode tab by itself. When the electrode assembly 110 is wound into a cylindrical shape, the uncoated portion 15 of the first electrode sheet 11 is disposed on one side (the top or bottom side in Figure 1) in the axial direction, and the uncoated portion 15 of the second electrode sheet 12 can be disposed on the other side in the axial direction. The uncoated portion 15 of the first electrode sheet 11 and the uncoated portion 15 of the second electrode sheet 12 can be formed to have the same width. Alternatively, the uncoated portion 15 of the first electrode sheet 11 and the uncoated portion 15 of the second electrode sheet 12 can be formed to have different widths. The first electrode sheet 11 can be a negative electrode sheet coated with a negative electrode active material, and the second electrode sheet 12 can be a positive electrode sheet coated with a positive electrode active material. Of course, the first electrode sheet 11 can be a positive electrode sheet coated with a positive electrode active material, and the second electrode sheet 12 can be a negative electrode sheet coated with a negative electrode active material. Each of the first electrode sheet 11 and the second electrode sheet 12 includes a current collector composed of a metal foil and a layer of active material. The metal foil can be aluminum or copper. The layer of active material can be applied as a coating on one or both surfaces of each of the first electrode sheet 11 and the second electrode sheet 12. The width of the uncoated portion 15 is significantly less than the width of the coated portion 14. The uncoated portion 15 may be formed in the form of a narrow band. Alternatively, the uncoated portion 15 may consist of a plurality of segments separated from each other along a longitudinal direction and arranged in a sawtooth pattern. The shape of each segment may be quadrangular, triangular, semicircular, semi-elliptical, parallelogram-shaped, or similar. The uncoated portion 15 may have a shape in which a partial section C is removed near one side of the core. The corresponding section may be removed by laser processing or similar means before winding after forming the electrode stack 10. Of course, the corresponding section may have a shape in which the uncoated portion of the corresponding C section is removed beforehand in an operation of providing the electrode sheet, or a removal portion 112a of the uncoated portion on the core side may be formed through post-processing after the winding operation. In the present invention, the active positive electrode material applied as a coating on the first electrode sheet 11 and the active negative electrode material applied as a coating on the second electrode sheet 12 can be used without limitation provided that these are active materials known in the art. The active positive electrode material may include a layered compound or a compound substituted with one or more transition metals such as lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2); lithium manganese oxides (LiMnO2) such as the chemical formula Li1+xMn2xO4 (where x is from 0 to 0.33), LiMnO3, LiMn2O3 and LiMnO2; copper lithium oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiFe3O4, V2O5 and Cu2V2O7; Ni site-type lithium nickel oxides expressed by the chemical formula LiNi1-xMxO2 (where M is Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x is from 0.01 to 0.3); lithium and manganese compound oxides expressed by the chemical formula LiMn2-xMxO2 (where M = Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu or Zn); LiMn2O4 wherein Li in the formula is partially substituted with alkaline earth metal ions; a disulfide compound;and Fe2(MoO4)3, or a compound whose main component is a lithium intercalation material, such as a compound oxide formed by a combination thereof. Although the above types are used as the active positive electrode material, the present invention is not limited to this. For example, the positive electrode current collector has a thickness of 3 to 500 µm. The positive electrode current collector is not particularly limited as long as it is conductive and does not cause chemical changes in a battery. Examples of positive electrode current collectors include stainless steel, aluminum, nickel, titanium, carbon, or calcined aluminum or stainless steel whose surface has been treated with carbon, nickel, titanium, silver, or similar materials. The electrode current collector may have fine irregularities formed on its surface to increase adhesion between the electrode current collector and the positive electrode active material. The electrode current collector can be used in various forms, such as a film, sheet, foil, mesh, porous body, foamed body, non-woven fabric body, and similar materials.A conductive material may be further mixed with particles of positive electrode active material. The conductive material is added in an amount of 1 to 50% by weight, based on the total weight of the mixture, including the positive electrode active material. The conductive material is not particularly limited, provided it has high conductivity without causing chemical changes in the battery. Examples of conductive materials may include graphite, such as natural and synthetic graphite; carbon black, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers, such as carbon fiber and metal fiber; metal powders, such as carbon fluoride, aluminum, and nickel powders; conductive filaments, such as zinc oxide and potassium titanate; conductive oxides, such as titanium oxide; and conductive materials, such as a polyphenylene derivative. Furthermore, the negative electrode sheet can be manufactured by applying and drying particles of negative electrode active material onto a negative electrode current collector, and may also include components such as the conductive material described above, a binder, a solvent, and the like as required. For example, the negative electrode current collector has a thickness of 3 to 500 µm. The negative electrode current collector is not particularly limited as long as it is conductive without causing chemical changes in a battery. Examples of negative electrode current collectors may include copper, stainless steel, aluminum, nickel, titanium, calcined carbon, aluminum or stainless steel whose surface has been treated with carbon, nickel, titanium, silver, or the like, an aluminum-cadmium alloy, or the like.Furthermore, as a positive electrode current collector, fine irregularities can be formed on the surface to enhance the bonding strength of the negative electrode active material, and it can be used in various forms such as a film, a sheet, a blade, a net, a porous body, a foamed body, a non-woven fabric body, and the like. Examples of the active negative electrode material may include a carbon such as non-graphitized carbon or graphite-based carbon; a metal complex oxide such as LixFe2O3 (0 <= x <= 1) , LixWO2 (0 <= x <= 1) , SnxMe1-xMe'yOz (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, elements of Group I, II and III in the periodic table, a halogen; 0 < x <= 1) ; 1 <= y <= 3; 1 <= z <= 8) ; a lithium metal; a lithium alloy; a silicon-based alloy; a tin-based alloy; an oxide such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4 or Bi2O5; a conductive polymer such as polyacetylene; a material based on Li-Co-Ni or similar. A binding polymer that can be used in the electrode sheet is a component that helps to bind the electrode active material particles and the conductive material and to bind the electrode active material particles to the electrode current collector, and is added in an amount of, for example, 1 to 50% by weight based on the total weight of the mixture that includes the electrode active material particles.Examples of the binding polymer may include at least one binding polymer selected from the group consisting of poly(vinylidene fluoride)-co-hexafluoropropylene (PVdF), poly(vinylidene fluoride)-co-trichloroethylene, polymethyl methacrylate, poly(butyl acrylate), polyacrylonitrile, polyvinylpyrrolidone, poly(vinyl acetate), polyethylene-co-vinyl acetate, poly(ethylene oxide), polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinyl alcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, and carboxylmethylcellulose, or a mixture of two or more of the same, but the present invention is not limited to these. Non-limiting examples of solvents used in the manufacture of electrodes include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, water, or a mixture thereof.Such solvents provide an appropriate level of viscosity so that a paste coating layer can be formed at a desired level on an electrode current collector surface. Separator 13 includes a porous polymer substrate, and a porous coating layer is located over both surfaces of the porous polymer substrate and includes inorganic particles and a binding polymer. The porous polymer substrate can be a polyolefin-based porous substrate. The porous polyolefin substrate can be in the form of a film or a non-woven web. Due to its porous structure, as described above, the electrolyte can move smoothly between the positive and negative electrodes. This porous structure enhances the substrate's electrolyte impregnation properties, ensuring excellent ionic conductivity and preventing an increase in resistance within the electrochemical device, thus avoiding performance degradation. The porous polyolefin substrate used in the present invention can be any flat porous substrate commonly used in electrochemical devices, and the material or shape thereof can be selected in various ways as desired. The porous polyolefin substrate may be, but is not limited to, a nonwoven film or web made of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene, or a mixture of two or more of these. However, the present invention is not limited to this. The porous polyolefin substrate may have a thickness of 8 to 30 µm, but this is only an example, and the porous polyolefin substrate may also have a thickness outside the above range, taking into account the mechanical properties or high-efficiency charge / discharge characteristics of a battery. The separator 13 according to the present invention may have a thickness of 1 to 100 µm or 5 to 50 µm. When the thickness of the separator 13 is less than 1 µm, its function may not be sufficiently exhibited, and deterioration of the mechanical properties may occur. When the thickness of the separator 13 is greater than 100 µm, the battery characteristics may deteriorate during high-rate charging / discharging. Furthermore, the separator 13 may have a porosity of 40 to 60% and an air permeability of 150 to 300 s / 100 ml. When the separator 13 is used according to an embodiment of the present invention, because the porous coating layer is arranged on both sides of the porous polymer substrate, a solid electrolyte interface layer can be formed uniformly due to the improved impregnation performance with respect to the electrolyte, and superior air permeability can be ensured compared to a conventional single-sided inorganic-coated separator 13. For example, the air permeability can be no more than 120 s / 100 cc. Furthermore, even when the inorganic porous coating layer is arranged on both sides of the porous polymer substrate, a thickness comparable to that of the conventional single-sided inorganic-coated separator 13 can be achieved. For example, the thickness can be no more than 15.0 µm. Furthermore, when the separator 13 is used according to an embodiment of the present invention, its stability can be improved to ensure its heat and pressure resistance properties. Specifically, it is possible to ensure a heat resistance property with a heat shrinkage property of 5% or less at 180°C and a puncture resistance of 550 gf or more. Damage to or penetration of the separator 13 in a stepped portion can be prevented when core deformation occurs during a battery cycle in which the separator 13 is used. A set of electrodes manufactured using the electrode stack described above will be described. Figure 4 is a perspective view illustrating a state in which the electrode cell body portion according to the present invention is cut by a first cutter portion; Figure 5 is a perspective view illustrating the first cutter portion according to the present invention; Figure 6 is a rear view illustrating the first cutter portion according to the present invention; Figure 7 is a plan view illustrating a state in which an uncoated portion of the electrode cell body portion is trimmed by a second cutter portion according to the present invention; Figure 8 is a perspective view illustrating a state before the uncoated portion of the electrode cell body portion is trimmed by the second cutter portion according to the present invention.Figure 9 is a side view illustrating a state in which the second cutter portion according to the present invention trims the uncoated portion of the electrode cell body portion; Figure 10 is a perspective view illustrating a state in which a pressure portion presses an uncut portion in a state in which the second cutter portion according to the present invention has trimmed the uncoated portion of the electrode cell body portion; Figure 11 is a perspective view illustrating a state in which a forming portion is formed by pressing the uncut portion by the pressure portion according to the present invention; and Figure 12 is a side view illustrating the state in which the forming portion is formed by pressing the uncut portion by the pressure portion according to the present invention. Referring to Figures 4 to 12,The electrode assembly 110 includes an electrode cell body portion 111, a plurality of cutting surface portions 115, and a plurality of forming portions 117. The electrode cell body portion 111 is a cylindrical portion coiled in a Swiss roll-like shape, with the separator 13 stacked between the first electrode sheet 11 and the second electrode sheet 12. As described above, the uncoated portion 15, which is not coated with the active material layer, is formed at the end portion of each of the first electrode sheet 11 and the second electrode sheet 12 in the width direction and is positioned on either side of the electrode cell body portion 111 in the axial direction, extending in the axial direction. The electrode cell body portion 111 can be formed by winding the stack, which extends lengthwise in the longitudinal direction, around a winding rod (not shown) and removing the winding rod from the electrode cell body portion 111. In this case, as a larger number of the first electrode sheets 11, second electrode sheets 12, and spacers 13 are stacked onto the electrode stack 10, the winding time and the fabrication time of the electrode assembly 110 can be reduced. A hollow core portion 112 is configured at a location from which the winding rod is removed from the electrode cell body portion 111. The uncoated portion 15 of the first electrode sheet 11 is exposed to a predetermined height on one side of the electrode cell body portion 111 in the axial direction, and the uncoated portion 15 of the second electrode sheet 12 is exposed to a predetermined height on the other side of the electrode cell body portion 111 in the axial direction. In addition, a recessed portion 112a is arranged in the section of the uncoated portion, which is adjacent to the core portion 112, due to the removed portion C of the uncoated portion described above. A first cutter portion 210 cuts the uncoated portion 15 of the electrode cell body portion 111 in the axial direction and separates a planned cut portion 115a and an uncut portion 117a in a peripheral direction. A first cut line 113 is formed between the planned cut portion 115a and the uncut portion 117a. The first cut line 113 is formed in a shape that extends in the axial direction from an end portion of the uncoated portion 15 toward the electrode cell body portion 111. In this case, the state in which the planned cut portion 115a and the uncut portion 117a are erected along the axial direction of the electrode cell body portion 111 is maintained as is. A second cutter portion 220 cuts a lower portion of the planned cut portion 115a from the uncoated portion 15 in the axial direction in a radial direction and removes the planned cut portion 115a from the electrode cell body portion 111. The second cutter portion 220 forms a second cut line 16a extending in a circumferential direction in the lower portion of the uncoated portion 15, which is positioned in a region corresponding to the planned cut portion 115a. The second cut line 16a is formed along the peripheral direction of the uncoated portion 15, and is arranged beneath each of several portions of the uncoated portion, which are arranged adjacently in the radial direction.When both end portions of the second cut line in the circumferential direction connect to the first cut lines 13 on both sides of the planned cut portion 115a in the circumferential direction, the planned cut portion 115a surrounded by a pair of first cut lines 13 and the second cut line is trimmed from the electrode cell body portion 111. A short portion of the uncoated portion remaining after the planned cut portion 115a is trimmed constitutes the cut surface portion 115. Accordingly, the cut surface portion 115 and the uncut portion 117a are arranged in the uncoated portion 15 of the electrode cell body portion 111. As the first cutter portion 210 is set up to cut and process the first cutting line 113, an ultrasonic cutter can be used to avoid a buckling phenomenon that may occur when the uncoated portion that has a small thickness is cut in the axial direction. The first cutter portion 210 includes a plurality of first blades 211 arranged in directions corresponding to the radial direction of the electrode cell body portion 111, and a first vibration generating portion 213 to which the first blades 211 are attached. The first portion of vibration generation 213 includes a circular plate and a vibration source to vibrate the circular plate. Each of the plurality of first blades 211 includes a base end portion attached to a surface of the circular plate of the first vibration-generating portion 213 and extends in a direction corresponding to the axial direction of the electrode cell body portion 111, and a sharp blade edge may be provided on a front end portion thereof. The plurality of first blades 211 is arranged radially around a central portion of the first vibration-generating portion 213. For example, a pair of first blades 211 defining the uncut portion 117a can be formed at four cross-shaped locations (+) around the central portion of the first vibration-generating portion 213. Alternatively, the pair of first blades 211 can be arranged radially at 60° intervals. Alternatively, a pair of second blades 221 can be arranged radially at three locations at 120° intervals. The angle between the pair of first blades 211 can be appropriately selected according to the diameter of the electrode cell body portion 111, the capacity of the battery pack, and the shape of the current-collecting plate to be welded to the electrode cell body portion 111. In the embodiment, a preferred structure is exemplified in which a pair of first blades 211 defining the uncut portion 117a are arranged parallel to each other. However, a pair of first blades 211 are not necessarily strictly parallel to each other. For example, the pair of first blades 211 may have a shape in which the distance between the first blades 211 gradually increases in a centrifugal or centripetal direction. Furthermore, although the first blade 211 is exemplified as having a straight line shape, it need not be. For example, the first blade 211 may also have a smoothly curved shape. The circumferential distance between the first pair of blades 211 and another pair of adjacent first blades 211 can decrease in the centripetal direction and increase in the centrifugal direction. This can define a sector shape of the cutting surface portions 115. In order for the second portion of cutter 220 to process the second cutting line, which will be described below, it is preferable that a distance between the first pair of blades 211 and a pair of first blades 211 adjacent to them in the circumferential direction does not increase in a centripetal direction or decrease in an infugal direction. The first vibration-generating portion 213 may include an ultrasonic vibrator. A first communication hole portion 215 is formed in the central portion of the first vibration-generating portion 213 to communicate with the core portion. The first vibration-generating portion 213 is ultrasonically vibrated when the first blade 211 moves in the axial direction of the electrode cell body portion 111 and cuts the uncoated portion 15. When a force with which the first blade 211 presses the uncoated portion 15 in the axial direction is not used to process the first cutting line 113 and presses the uncoated portion 15, there is a possibility that the uncoated portion 15 may buckle or that a portion of the uncoated portion 15 near the first cutting line 113 may become deformed such as bending or folding. When the first blade 211 is vibrated ultrasonically, the previous phenomenon when the first blade 211 cuts the uncoated portion 15 is avoided, and the cutting process is performed very smoothly. Consequently, the speed at which the uncoated portion 15 is cut can be improved, and the first cutting line 113 of the uncoated portion 15 can be formed smoothly. As long as the first blade 211 is vibrated, various vibration methods can be applied to the first vibration-generating portion 213. The second cutter portion 220 includes the second blades 221 configured to trim the uncoated portion 15 in the radial direction, and a second vibration generating portion 223 to which the second blades 221 are attached. The second blade 221 may have a shape in which its width decreases toward a front end portion thereof. Specifically, the second blade 221 may be provided in the form of a triangular plate or a wedge plate. For example, the second blade 221 may have a vertex portion formed at an angle 2 of 60° to 120°. The angle 2 of the vertex portion of the second blade 221 is formed to correspond to a central angle of the cutting surface portion 115, which will be described below. In the embodiment, a case is exemplified in which the blade 221 has a vertex angle of approximately 90°. The second blade 221 may be double-edged. That is, blade edges may be provided in positions corresponding to two oblique side portions, extending to the front end portion. When the second blade moves in the radial direction to form the second cutting line, first, the sharp front portion of the second blade cuts into and enters a central portion of the planned cutting portion 115a of the uncoated portion in the peripheral direction. As the second blade moves in the centripetal direction, both blade edges expand the second cutting lines on either side in the circumferential direction. When the second blade applies a force to a lateral surface of the uncoated portion in the radial direction, a large area of ​​the second blade does not contact the lateral surface of the uncoated portion at once; instead, the force is concentrated on the sharp front portion and applied to the uncoated portion.Consequently, by forming the second cutting line on the lateral surface of the uncoated portion, there is no instance where the uncoated portion is laterally compressed and deformed. Once the front end portion has trimmed and entered the uncoated portion, as the second cutter portion moves in the centripetal direction, both blade edges of the second cutter portion press the second cutting line in the peripheral direction to cut through it. This cutting method and the direction of the second cutter portion minimize deformation of the uncoated portion. The second vibration generation portion 223 may include an ultrasonic vibrator. This second vibration generation portion 223 is vibrated ultrasonically when the second blade 221 moves in the radial direction of the electrode cell body portion 111 and trims the uncoated portion 15. Consequently, the trimming speed of the uncoated portion 15 can be improved, and the cut surface portion 115 can be formed smoothly. As long as the second blade 221 is vibrating, various vibration methods can be applied to the second vibration generation portion 223. The recessed portion 112a is formed between the uncoated portion 15 and the core portion 112 on one or both sides of the electrode cell body portion 111 in the axial direction. The recessed portion 112a is ring-shaped to surround the core portion 112. A width W2 of the recessed portion 112a in the radial direction may be formed to be equal to, or slightly greater or less than, a height W1 of the uncoated portion 15. The recessed portion 112a is formed to be concentric with the core portion 112. The recessed portion 112a may be formed to be coplanar with, or slightly lower than, the cut surface portion 115. The plurality of cut surface portions 115 are formed by trimming the planned cut portion 115a, which is a portion of the uncoated portion 15, in the circumferential direction around the core portion 112 of the electrode cell body portion 111. In this case, the plurality of cut surface portions 115 can be arranged along the circumferential direction around the core portion 112 at equal intervals. Furthermore, each of the plurality of cut surface portions 115 can be formed with the same size and shape. The plurality of forming portions 117 are formed by pressing and folding the uncut portion 117a of the uncoated portion 15, which are arranged between the cutting surface portions 115, in a direction that crosses the axial direction, i.e., in the radial direction. The plurality of forming portions 117 can be formed by pressing and folding the uncut portion 117a of the uncoated portion 15 using a pressing portion 230, which will be described below. In this case, the plurality of forming portions 117 can be folded while continuously overlapping a plurality of uncut pieces that constitute the uncut portion 117a. Consequently, a forming portion 117 can be formed to be inclined with respect to the axial direction of the electrode cell body portion 111, or it can be formed to be flat by folding it completely. The plurality of forming portions 117 are portions welded to the current collector plates 130 and 140 to form a current path (a current passage). Additionally, the plurality of cutting surface portions 115 can also be welded to the current collector plates 130 and 140. However, because the cutting surface portion 115 is welded (i.e., laser-welded) to the current collector plates 130 and 140 in a state of being in linear contact with the current collector plates 130 and 140, the effect of increasing the current path by the cutting surface portion 115 is not as large compared to that of the forming portion 117.On the other hand, because the forming portion 117 is formed by folding down the uncut portion 117a in the radial direction of the uncut portion 117a, the forming portion 117 covers a gap between the uncoated portions 15 that are separated by as much as the thickness of the separator 13. Because the forming portion 117 is welded to the current-collecting plates 130 and 140 in the state of being in surface contact with them, the current path of the electrode assembly 110 and the current-collecting plates 130 and 140 can be increased relatively as an area of ​​the forming portion 117 is increased.Because the forming portion 117 increases the current path as much as the sum of the gaps between the uncoated portions 15, even when applied to a battery cell 100 that has a large capacity, an increase in the amount of heating of the battery cell 100 can be inhibited and the possibility of ignition can be reduced. When the cut surface portion 115 is exposed without being welded to the current collector plates 130 and 140, electrolyte impregnation can be enhanced when electrolyte is injected into the electrode assembly. Electrolyte impregnation can be reduced in the forming portion 117 due to bending of the uncut parts, but this is offset because the cut surface 115 is adjacent to the forming portion 117, and therefore there is no particular problem with electrolyte impregnation. According to the present invention, after the planned cutting portion 115a and the uncut portion 117a are separated from each other in the uncoated portion 15 in the peripheral direction by the first cutting portion configured to form the first cutting line in the axial direction, the cutting surface portion 115 is formed by trimming a lower end portion of the planned cutting portion 115a by the second cutter portion, and the forming portion 117 is formed by pressing and folding down the uncut portion 117a. Consequently, when the forming portion 117 is formed by pressing down the uncut portion 117a, a boundary portion 16 of the forming portion 117 and the cutting surface portion 115 can be prevented from tearing or becoming distorted and irregularly deformed. Furthermore, because the boundary portion 16 of the forming portion 117 and the shearing surface portion 115 are prevented from tearing or deforming, contact between the electrode sheets 11 and 12 of opposite polarities in the torn or deformed portion can be avoided. Additionally, because the boundary portion 16 of the uncoated portion 15 and the coated portion 14 is prevented from tearing or deforming, the active material applied to the coated portion 14 can be prevented from detaching from the coated portion 14, or a weakening of the bonding force can be prevented. Consequently, a decrease in the performance and capacity of the battery cell 100 can be inhibited. Furthermore, it can prevent the edge of the separator 13 from delamining or being damaged due to the torn or deformed portion of the border portion 16. Therefore, a short circuit between the first electrode sheet 11 and the second electrode sheet 12 can be avoided. In addition, the amount of heating of the battery cell 100 can be reduced, or the possibility of an explosion can be significantly reduced. Furthermore, the forming portion 117 is formed by pressing the uncut portion 117a in a state where the shear surface portions 115 are withdrawn on both sides of the uncut portion 117a. This prevents the uncut pieces of the uncut portion 117a from separating while simultaneously erecting obliquely due to elastic recovery. Additionally, when the uncut portion 117a is pressed with strong pressure using the pressing portion 230, the forming portions 117 (uncut pieces of the uncut portion 117a) can overlap each other in a state of close contact with the shear surface portions 115, keeping them as flat as possible.Consequently, the weld cross-sectional area can be significantly increased as the forming portion 117 and the cut portion are welded to the current collector plates 130 and 140 in a surface contact state. Furthermore, as the weld cross-sectional area increases, the cross-sectional area of ​​the current path also increases, and therefore the resistance of battery cell 100 can be significantly reduced. This is because resistance is inversely proportional to the cross-sectional area of ​​the current path. The cut surface portions 115 are sector-shaped along the circumferential direction around the core portion 112 of the electrode cell body portion 111. A vertex portion of the cut surface portion 115 is oriented toward the core portion 112. Because the cut surface portions 115 are sector-shaped, each forming portion 117 can be arranged radially around the core portion 112 among the plurality of cut surface portions 115. Furthermore, a width of a forming portion 117 on an outer side can be equal to or greater than a width of a forming portion 117 on a side of the core portion 112, depending on a central angle of the sector-shaped cut surface portions 115. The cutting surface portion 115 can have a central angle 1 (see Figure 7) from 60° to 120°. The central angle 1 is the angle at which both sides of a sector separate at the sector's vertex. When the central angle 1 of the cutting surface portion 115 is 90°, four cross-shaped portions of the cutting surface 115 can be formed in the circumferential direction of the uncoated portion 15. When the central angle 1 of the cutting surface portion 115 is 60°, six cut surfaces can be formed in the circumferential direction of the uncoated portion 15. When the central angle 1 of the cutting surface portion 115 is 120°, three cut surfaces can be formed in the circumferential direction of the uncoated portion 15. In the present invention, the central angle of the cutting surface portion is not limited to the above range.For example, the central angle can be 45° or 30°, or it can also be 180°. The cutting surface portion 115 can be formed by trimming portion 16a, which is separated outwards a predetermined distance in the axial direction from the boundary portion 16 between the uncoated portion 15 and the coated portion 14. Consequently, because the uncoated portion 15 is trimmed in a position separate from the coated portion 14 by the second cutter portion 220, the detachment of the active material applied to the coated portion 14 can be prevented. Furthermore, even when the uncoated portion 15 is slightly deformed and cut, damage or deformation of the coated portion 14 can be prevented. The center angle of the cutting surface portion 115 can be appropriately selected considering the diameter of the electrode cell body portion 111, the battery cell capacity 100, and similar factors. For example, as the diameter of the electrode cell body portion 111 increases, the center angle of the cutting surface portion 115 can be shaped to be close to 60°. This is because, as the diameter of the electrode cell body portion 111 increases, increasing the cross-sectional area of ​​the current path is advantageous for preventing heat generation or ignition; therefore, the center angle of the cutting surface portion 115 decreases to increase the area of ​​the forming portion 117. Furthermore, as the capacity of the electrode cell body portion 111 increases, the center angle of the cutting surface portion 115 can be shaped to be close to 60°. The forming portions 117 can be formed radially around the core portion 112 of the electrode cell body portion 111. When four forming portions 117 are formed in a cross shape, the center angle of the cutting surface portion 115 is 90°. When six forming portions 117 are formed radially around the core portion 112, the center angle of the cutting surface portion 115 is 60°. When three forming portions 117 are formed radially around the core portion 112, the center angle of the cutting surface portion 115 is 120°. Because the forming portions 117 are formed radially around the core portion 112, the current path can be distributed uniformly in the circumferential direction of the electrode cell body portion 111. The forming portion 117 can be formed in a shape such that the uncut portions 117a of the uncoated portion 15 are folded down towards the core portion 112 of the electrode cell body portion 111. Consequently, the forming portion 117 is prevented from protruding outwards from an outer circumferential surface of the electrode cell body portion 111, so that the electrode assembly 110 can be smoothly inserted into a battery can 120 when the battery cell 100 is manufactured. Furthermore, the forming portion 117 is prevented from being caught by the battery can 120. In the case where the uncut portions 117a are folded down towards the core portion 112 of the electrode cell body portion 111, when the uncut portion 117a adjacent to the core portion 112 is folded down, a phenomenon may occur in which the uncut portion 117a covers the core portion 112. That is, as shown in Figure 1A, the electrode cell body portion 111, which is manufactured without removing a partial section of the uncoated portion disposed on the core side, does not have the rebated portion 112a. When the uncut portion 117a exists in the uncoated portion of the winding, which is adjacent to the core portion 112, the forming portion 117 can cover the core portion 112 as the uncoated portion 117a adjacent to the core portion 112 is folded down. The core portion 112 can be a path through which an electrolyte is injected, and in some cases, the core portion 112 can be a path through which a welding rod is inserted. Consequently, it is preferable that the core portion 112 be open in the axial direction. Accordingly, as shown in Figure 1B, when the electrode assembly is manufactured in a state where the partial section of the uncoated portion, located on the core side, is pre-trimmed as described above, the recessed portion 112a is arranged in the form in which the uncoated portion adjacent to the core portion 112 is removed, and when the forming portion 117 is formed in this state, there is no case where the core portion 112 is covered. The width W2 of the recessed portion 112a in the radial direction can be shaped to be equal to the height W1 of the uncoated portion (see Figure 9). In addition, the width W2 of the recessed portion 112a in the radial direction can also be shaped to be slightly greater or less than the height W1 of the uncoated portion. The formation portions 117 can be formed parallel to the radial direction of the electrode cell body portion 111. The formation portions 117 can be formed symmetrically around the core portion 112 of the electrode cell body portion 111. Consequently, the formation portions 117 can form the current path that has almost the same area in the radial direction of the electrode cell body portion 111. Core portion 112 can be formed in a central portion of electrode cell body portion 111. Core portion 112 is formed in a hollow shape that passes through the central portion of electrode cell body portion 111. A cross-section of core portion 112 can be circular. Because core portion 112 is formed in a hollow shape, an electrolyte injector (not shown) can inject electrolyte through core portion 112 after electrode assembly 110 is inserted into battery can 120. Consequently, the manufacturing time of battery cell 100 can be reduced by minimizing the electrolyte injection time. Furthermore, when the electrolyte injector is inserted into core portion 112, electrode sheets 11 and 12 or the separator 13 near core portion 112 can be prevented from being caught, torn, or damaged. The electrode cell body portion 111 can be formed into a cylindrical shape. Accordingly, the electrode cell body portion 111 can be inserted such that an outer side surface of the electrode cell body portion 111 is in close contact with an inner side surface of the cylindrical battery can 120. A method for manufacturing the battery cell according to the present invention will now be described. A separator 13 is stacked between a first electrode sheet 11 and a second, leaf-shaped electrode sheet 12 (S11). At this point, a structure in which the first electrode sheet 11, the second electrode sheet 12, and the separator 13 are stacked is called the electrode stack 10. In the electrode stack 10, an uncoated portion 15 of the first electrode sheet 11 projects from one side of the electrode stack 10 in a width direction, and an uncoated portion 15 of the second electrode sheet 12 projects from the other side of the electrode stack 10 in a width direction. The first electrode sheet 11, the second electrode sheet 12, and the spacer 13 are wound into a Swiss roll (S12). At this point, the electrode stack 10 is wound onto a winding rod to form an electrode assembly 110, and the winding rod is separated from the electrode assembly 110. A hollow core portion 112 is formed in the central portion of the electrode assembly 110, from which the winding rod is extracted. The core portion 112 is shaped to pass through the electrode assembly 110 in an axial direction. As a larger number of the first electrode sheets 11, second electrode sheets 12, and spacers 13 are stacked onto the electrode stack 10, the winding time and the manufacturing time of the electrode assembly 110 can be reduced. The uncoated portion 15 of each of the first electrode sheet 11 and the second electrode sheet 12 is radially cut as a first cutter portion 210 moves in the axial direction of a battery cell 100 (S13). At this point, the first cutter portion 210 cuts the uncoated portion 15 of the electrode cell body portion 111 in the axial direction to separate a planned cut portion 115a and an uncut portion 117a. In this case, the state in which the planned cut portion 115a and the uncut portion 117a are erected along the axial direction of the electrode cell body portion 111 is maintained as is. As a second cutter portion 220 moves in a radial direction of the battery cell 100, a portion of the uncoated portion 15 is trimmed, thereby forming a cut surface portion 115 (S14). The second cutter portion 220 cuts the planned cut portion 115a from the uncoated portion 15 in the radial direction and removes the planned cut portion 115a from the electrode cell body portion 111. Consequently, the cut surface portion 115 and the uncut portion are separated from each other in the uncoated portion 15 of the electrode cell body portion 111. The uncut portions 117a of the uncoated portion 15 are pressed by a pressing portion 230 and folded to form forming portions 117 (S15). A plurality of forming portions 117 are arranged between the cutting surface portions 115 and are formed by pressing and folding the uncut portions 117a of the uncoated portion 15. The plurality of forming portions 117 can be formed by pressing and folding the uncut portions 117a of the uncoated portion 15 using a pressing portion 230, which is described below. In this case, the plurality of forming portions 117 can be folded while a plurality of uncut pieces constituting the uncut portions 117a are continuously overlapped. Consequently, the formation portions 117 can be formed to tilt slightly with respect to the axial direction of the electrode cell body portion 111. Because the cut surface portion 115 is laser-welded to the current-collecting plates 130 and 140 in a state of linear contact with them, the cut surface portion 115 does not substantially increase the current path. On the other hand, because the forming portion 117 is formed by folding down the uncut portion 117a in the radial direction, the forming portion 117 fills a gap between the uncoated portions 15, which are separated by a distance equal to one thickness of the separator 13. Because the forming portion 117 is welded to the current-collecting plates 130 and 140 in a state of surface contact with them, the current path of the electrode assembly 110 and the current-collecting plates 130 and 140 can be further increased because the area of ​​the forming portion 117 is increased.Because the forming portion 117 increases the current path as much as the sum of the gaps between the uncoated portions 15, even when applied to a battery cell 100 that has a large capacity, an increase in the amount of heating of the battery cell 100 can be inhibited and the possibility of ignition can be reduced. After the planned cut portion 115a and the uncut portion 117a are separated from each other at the uncoated portion 15, the planned cut portion 115a is trimmed to form the cut surface portion 115, and the uncut portion 117a is pressed and folded to form the forming portion 117. Consequently, when the forming portion 117 is formed by pressing the uncut portion 117a, it is possible to prevent a boundary portion 16 of the forming portion 117 and the cut surface portion 115 from tearing or distorting and becoming irregularly deformed. Furthermore, it can prevent the edge of the separator 13 from delamining or being damaged due to the torn or deformed portion of the border portion 16. Therefore, a short circuit between the first electrode sheet 11 and the second electrode sheet 12 can be avoided. In addition, the amount of heating of the battery cell 100 can be reduced, or the possibility of an explosion can be significantly reduced. The cut surface portions 115 can be sector-shaped along a circumferential direction around the core portion 112 of the electrode cell body portion 111. A vertex portion of the cut surface portion 115 is oriented towards the core portion 112. Because the cut surface portions 115 are sector-shaped, each forming portion 117 can be arranged radially around the core portion 112 among a plurality of cut surface portions 115. The cutting surface portion 115 can have a center angle 1 of 60° to 120°. For example, when the center angle 1 of the cutting surface portion 115 is 90°, four cutting surface portions 115 can be formed in a cross shape in the circumferential direction of the uncoated portion 15. When the center angle 1 of the cutting surface portion 115 is 60°, six cut surfaces can be formed in the circumferential direction of the uncoated portion 15. When the center angle 1 of the cutting surface portion 115 is 120°, three cut surfaces can be formed in the circumferential direction of the uncoated portion 15. The cutting surface portion 115 can be formed by trimming a portion that is offset outward a predetermined distance in the axial direction from the boundary portion 16 between the uncoated portion 15 and a coated portion 14.Consequently, because the uncoated portion 15 is trimmed at a separate position from the coated portion 14 by the second cutter portion 220, the detachment of an active material applied to the coated portion 14 can be prevented. Furthermore, even when the uncoated portion 15 is slightly deformed and cut, damage or deformation of the coated portion 14 can be prevented. The forming portions 117 can be formed radially around the core portion 112 of the electrode cell body portion 111. When four forming portions 117 are formed in a cross shape, the central angle 1 of the cutting surface portion 115 is 90°. When six forming portions 117 are formed radially around the core portion 112, the central angle 1 of the cutting surface portion 115 is 60°. When three forming portions 117 are formed radially around the core portion 112, the central angle 1 of the cutting surface portion 115 is 120°. Because the forming portions 117 are formed radially around the core portion 112, the current path can be distributed uniformly in the circumferential direction of the electrode cell body portion 111.The forming portion 117 can be formed in a shape such that the uncut portions 117a of the uncoated portion 15 are folded down towards the core portion 112 of the electrode cell body portion 111. Consequently, the forming portion 117 is prevented from protruding outwards from an outer circumferential surface of the electrode cell body portion 111, so that the electrode assembly 110 can be smoothly inserted into a battery can 120 when the battery cell 100 is manufactured. Furthermore, the forming portion 117 is prevented from being caught by the battery can 120. The formation portions 117 can be formed parallel to the radial direction of the electrode cell body portion 111. The formation portions 117 can be formed symmetrically around the core portion 112 of the electrode cell body portion 111. The first cutter portion 210 cuts the uncoated portion 15 while it is vibrated by a first vibration generating portion 213. The first vibration generating portion 213 may include an ultrasonic vibrator. Because the uncoated portion 15 is cut while the first cutter portion 210 vibrates, the cutting performance and speed of the uncoated portion 15 can be improved. The second cutter portion 220 cuts the uncoated portion 15 while it is vibrated by a second vibration generating portion 223. The second vibration generating portion 223 may include an ultrasonic vibrator. Because the uncoated portion 15 is cut while the second cutter portion 220 vibrates, the cutting performance and speed of the uncoated portion 15 can be improved. The processing of the cutting surface portion can be done in a way in which the processing by the first cutter portion is done first, and then the processing by the second cutter portion is done. A battery cell manufactured using the electrode assembly described above will be described. Referring to Figure 13, the battery cell 100 according to the present invention includes the electrode assembly 110, the battery can 120, a sealing cap portion 150, and a first current collector plate 130. Because the 110 electrode assembly is substantially the same as that described above, a description of it will be omitted. The electrode assembly 110 is housed in the battery can 120. The battery can 120 is electrically connected to one of the first electrode sheets 11 and the second electrode sheet 12 and has a first polarity. The battery can 120 may be made of a conductive material to allow current to flow through it. For example, the battery can 120 may be made of a material including stainless steel, aluminum, or a similar material. The battery can 120 may be formed in a cylindrical shape with an open end formed on one side. The sealing cap portion 150 seals the open end of the battery can 120. The sealing cap portion 150 is installed to isolate it from the battery can 120. The sealing cap portion 150 prevents external foreign substances or moisture from penetrating the battery can 120. The first current collector plate 130 is electrically connected to the other of the first electrode sheet 11 and the second electrode sheet 12 and has a second polarity. The first current-collecting plate 130 can be arranged between the electrode assembly 110 and the sealing cap portion 150. The first current-collecting plate 130 is electrically connected to the sealing cap portion 150. The first current-collecting plate 130 can be welded to the uncoated portion 15 of the first electrode sheet 11 and the second electrode sheet 12. At this point, the forming portion 117 of the uncoated portion 15 can be welded to the first current-collecting plate 130 in a state of being in surface contact with it, and the cutting surface portion 115 of the uncoated portion 15 can be welded to the first current-collecting plate 130 in a state of being in linear contact with it.Therefore, because the cross-sectional area of ​​the weld on the uncoated portion 15 and the first current collector plate 130 is increased, the cross-sectional area of ​​a current path is increased, thereby significantly reducing the electrical resistance of the battery cell 100. In addition, the amount of heating of the battery cell 100 can be reduced, and the possibility of ignition of the battery cell 100 can be lowered. The first electrode sheet 11 can be a negative electrode sheet and the second electrode sheet 12 can be a positive electrode sheet. Alternatively, the first electrode sheet 11 can be a positive electrode sheet and the second electrode sheet 12 can be a negative electrode sheet. An electrolyte is injected into the battery can 120 through the core portion 112 of the electrode assembly 110. The electrolyte can be a salt that has an A+B- structure. In this case, A+ includes an alkali metal cation such as Li+, Na+, or K+, or a combination thereof. In addition, B- includes at least one anion selected from the group consisting of F-, Cl-, Br-, I-, NO3-, N(CN)2-, BF4-, ClO4-, AlO4-, AlCl4-, PF6-, SbF6-, AsF6-, BF2C2O4-, BC4O8-, (CF3)2PF4-, (CF3)3PF3-, (CF3)4PF2-, (CF3)5PF-, (CF3)6P-, CF3SO3-, C4F9SO3-, CF3CF2SO3-, (CF3SO2)2N-, (FSO2)2N-, CF3CF2(CF3)2CO-, (CF3SO2)2CH-, (SF5)3C-, (CF3SO2)3C-, CF3(CF2)7SO3-, CF3CO2-, CH3CO2-, SCN- and (CF3CF2SO2) 2N-. The electrolyte can also be used in a state where it is dissolved in an organic solvent. The organic solvent can be propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, dietoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), β-butyrolactone, or a mixture thereof. The sealing cap portion 150 may further include an insulator 157 configured to cover the first current collector plate 130 and having an edge interposed between the first current collector plate 130 and an inner circumferential surface of a support portion 122. The insulator 157 electrically isolates the sealing cap portion 150 from the battery can 120. The 157 insulator can be made from a polymer resin that has insulating properties. For example, the 157 insulator can be made from polyethylene, polypropylene, polyimide, or poly(butylene terephthalate). The sealing cap portion 150 includes a cap plate 151 installed to block the open end of the battery can 120. The entire cap plate 151 can be formed into a circular plate shape. An external terminal 152 is formed in a central portion of the cap plate 151 to protrude outwards (the top side in Figure 13). The sealing cap portion 150 includes a vent plate 153 arranged beneath the cap plate 151. The vent plate 153 ruptures when the internal pressure of the battery can 120 is greater than or equal to a predetermined pressure. The vent plate 153 prevents an explosion of the battery cell 100. The vent plate 153 and the first current collector plate 130 are electrically connected to each other via a conductor portion 155. In addition, the vent plate 153 is in contact with the cover plate 151 to form a portion of the current path. The inwardly recessed support portion 122 from the battery can 120 is formed below the open end of the battery can 120. The vent plate 153 and the lid plate 151 are stacked on one upper side of the support portion 122. Insulator 157 is interposed between an inner side surface of the support portion 122 and a peripheral portion of each of the vent plate 153 and the cap plate 151. Insulator 157 covers the first current collector plate 130, and the edge of insulator 157 is interposed between the first current collector plate 130 and the inner circumferential surface of the support portion 122. Insulator 157 forms a portion of the sealing cap portion 150. A clamping portion 123 is formed on the open end of the battery can 120 to press against the cap plate 151 and the insulator 157. The clamping portion 123 and the open end of the battery can 120 are folded inward to seal a gap between a circumference of the cap plate 151 and the open end of the battery can 120. Because the clamping portion 123 on the support portion 122 presses against and secures the circumferences of each of the first current collector plate 130 and the vent plate 153, the movement of the first current collector plate 130 and the vent plate 153 is restricted, thereby improving the assembly stability of the battery cell 100. Furthermore, it is possible to prevent the seal of the battery can 120 from breaking due to an external impact. One of the first electrode sheet 11 and the second electrode sheet 12 can be electrically connected to the battery can 120 via a second current collector plate 140. At this point, the second current collector plate 140 can be welded to the uncoated portion 15 formed on one of the first electrode sheet 11 and the second electrode sheet 12. The cut surface portion 115 and the formed portion 117 of the uncoated portion 15 can be laser-welded to the second current collector plate 140. Therefore, because the weld cross-sectional area of ​​the uncoated portion 15 and the second current collector plate 140 is increased, the cross-sectional area of ​​the current path is increased, thereby significantly reducing the electrical resistance of the battery cell 100.In addition, the amount of heating of battery cell 100 can be reduced, and the possibility of ignition of battery cell 100 can be lowered. Furthermore, the uncoated portion 15 formed on one of the first electrode sheet 11 and the second electrode sheet 12 can be welded directly to the inner side surface of the battery can 120. Figure 15 is a perspective view illustrating a state in which the electrode assembly according to the present invention is housed in a package housing. Referring to Figure 15, a battery pack according to the embodiment of the present invention includes an assembly to which the cylindrical battery cells 100 are electrically connected and a pack housing 101 configured to accommodate the assembly. The cylindrical battery cell 100 can be one of the battery cells 100 according to the embodiment described above. For ease of description, components such as a bus bar (not shown), a cooling unit (not shown), an external terminal (not shown), and the like for electrically connecting the cylindrical battery cells 100 are omitted from the drawing. The battery pack can be mounted on a 300 series vehicle. The 300 series vehicle can be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle includes either a four-wheeled vehicle or a two-wheeled vehicle. Figure 16 is a view to describe a vehicle including the battery pack according to the present invention. Referring to Figure 16, the vehicle 300 according to one embodiment of the present invention includes the battery cell 100 according to one embodiment of the present invention. The vehicle is powered by receiving energy from the battery cell 100 according to one embodiment of the present invention. Although the present invention has been described with reference to the illustrated drawings, it is to be understood that the present invention is not limited to the embodiments and drawings disclosed herein, and those skilled in the art will appreciate that various modifications are possible without departing from the scope and spirit of the present invention. Furthermore, although the operating effects according to the configuration of the present invention are not explicitly described while describing one embodiment of the present invention, it should be appreciated that the predictable effects of the configuration are also to be recognized.

Claims

1. A cutting device configured to cut at least a portion of an uncoated portion (15) of an electrode assembly (110) including an electrode cell body portion (111) in which a separator (13), a first electrode sheet (11), and a second sheet-like electrode sheet (12) are wound in a stacked state, and the uncoated portion (15) not coated with a layer of active material is disposed over an end portion of at least one of the first electrode sheet (11) and the second electrode sheet (12) in a width direction thereof, the cutting device comprising: a first cutter portion (210) configured to form first cutting lines in the uncoated portion (15) in an axial direction of the electrode assembly (110) while moving in the axial direction,the uncoated portion extending in the axial direction; and the cutting device being characterized by a second cutter portion (220) configured to form a second cutting line in the uncoated portion (15) in a peripheral direction of the electrode assembly while moving in a radial direction of the electrode assembly (110), the uncoated portion being wound in the peripheral direction, and the second cutter portion forming a cutting surface portion (115) in the uncoated portion (15) of the electrode assembly (110) by connecting the second cutting line to the first cutting lines and trimming a portion of the uncoated portion defined by the first cutting lines and the second cutting line.

2. The cutting device of claim 1,wherein the first cutter portion (210) includes a plurality of first blades (211) arranged radially and extending in the axial direction.

3. The cutting device of claim 1, wherein the first cutter portion (210) further includes a first vibration-generating portion (213).

4. The cutting device of claim 1, wherein the second cutter portion (220) is formed in a triangular shape having two sides on which blade edges are formed such that the uncoated portion (15) is cut into a sector shape.

5. The cutting device of claim 1,wherein the second cutter portion (220) further includes a second vibration generating portion (223).

6. An electrode assembly processing device comprising: the cutting device of claim 1; and a pressing portion (230) configured to press and flatten an uncut portion (117a) of the uncoated portion (15) that is not trimmed by the second cutter portion, to form a forming portion (117), wherein the pressing portion (230) flattens the uncut portion (117a) of the uncoated portion (15) in a radial direction of the electrode cell body portion (111) while moving in the radial direction of the electrode cell body portion (111).

7. A method for manufacturing a battery cell (100), the method comprising: manufacturing an electrode cell body portion (111) by stacking and rolling a first electrode sheet (11),a second electrode sheet (12) and a leaf-shaped separator (13); forming first cutting lines (210) in an uncoated portion (15) of each of the first electrode sheet (11) and the second electrode sheet (12) in an axial direction of the electrode cell body portion (111) using a first cutter portion moving in the axial direction; characterized in that the method further comprises forming a second cutting line (220) in a peripheral direction of the uncoated portion (15) that is wound in the peripheral direction using a second cutter portion moving in a radial direction of the electrode cell body portion (111),and forming a cut surface portion (115) in the uncoated portion (15) of the electrode assembly (110) by connecting the second cut line to the first cut lines and trimming a portion of the uncoated portion defined by the first cut lines and the second cut line; and forming a forming portion (117) by pressing an uncut portion (117a) of the uncoated portion (15) and folding the uncut portion (117a) in the radial direction using a pressing portion (230).

8. The method of claim 7, wherein the cut surface portion (115) is formed in a sector shape along a circumferential direction around a core portion (112) of the electrode cell body portion (111).

9. The method of claim 8, wherein the cut surface portion (115) has a center angle of 60° to 120°.

10. The method of claim 7,wherein the forming portion (117) is formed radially around a core portion (112) of the electrode cell body portion (111).

11. The method of claim 7, wherein the forming portion (117) is formed in a manner in which the uncut portion (117a) of the uncoated portion (15) is folded down towards a core portion (112) of the electrode cell body portion (111).

12. The method of claim 7, wherein the forming portion (117) is formed along the radial direction of the electrode cell body portion (111).

13. The method of claim 7, wherein the cut surface portion (115) is formed by trimming a portion of the uncoated portion that is separated outwards a predetermined distance in the axial direction from a boundary portion (16) of the uncoated portion (15) and a coated portion (14).

14. The method of claim 7,wherein the first cutter portion (210) cuts the uncoated portion (15) while being vibrated by a first vibration generating portion (213).

15. The method of claim 7, wherein the second cutter portion (220) trims the uncoated portion (15) while being vibrated by a second vibration generating portion (223).

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