Cylindrical battery, battery pack and vehicle

Abstract

Cylindrical battery, comprising: an electrode assembly in which a first electrode, a second electrode, and a separator disposed therebetween are wound around a winding axis of the electrode assembly to define a core and an outer periphery of the electrode assembly; and a cylindrical battery housing that houses the electrode assembly, wherein a cross section of the electrode assembly perpendicular to the winding axis direction includes a first fan-shaped portion and a second fan-shaped portion each having a circumferential angle of 180 degrees or less in a winding direction, wherein the first fan-shaped region is defined as a voltage-susceptible region by a first straight line and a second straight line extending from a center of the core through a core-side end of the first electrode and a core-side end of the second electrode, respectively, and through an outer periphery of the first fan-shaped region along the winding direction, wherein a second fan-shaped region is defined by a third straight line and a fourth straight line extending from the center of the core through an outer peripheral end of the first electrode and an outer peripheral end of the second electrode, respectively, and through an outer periphery of the second fan-shaped region along the winding direction as a voltage boosting region, and wherein the electrode assembly has a winding structure in which at least the outer peripheral end of the first electrode of the voltage amplifying region is spaced from an inner side of the voltage-susceptible region along a circumferential direction of the cross section of the electrode assembly.

Description

TECHNICAL FIELDThe present disclosure relates to a cylindrical battery, a battery pack, and a vehicle, and more particularly, to a cylindrical battery capable of maintaining the symmetry and circularity of an electrode array core despite the increase in the charge and discharge cycle by controlling the positions of the ends of a positive electrode and a negative electrode in a winding direction, and a battery pack and a vehicle including the same.The present application claims priority to Korean Patent Application No. 10-2022-0089226 filed in the Republic of Korea on Jul. 19, 2022, the disclosures of which are incorporated herein by reference.PRIOR ARTSecondary batteries that are easily applicable to various product groups and have electrical characteristics such as high energy density are universally applied not only to portable devices but also to electric vehicles (EVs), hybrid electric vehicles (HEVs), or plug-in hybrid electric vehicles (PHEVs) driven by an engine.Hereinafter, an electric vehicle is used as a term to refer to a vehicle that includes an electrically driven motor, such as EV, HEV, and PHEV.These secondary batteries are attracting attention as a new power source to improve environmental friendliness and energy efficiency because they have the primary advantage that they can dramatically reduce the use of fossil fuels, as well as the secondary advantage that no byproducts are generated by the use of energy.Secondary batteries that are currently widely used in the art include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, and the like. A unit secondary battery has an operating voltage of about 2.5 V to 4.5 V. Therefore, when a higher output voltage is required, a battery pack is configured by connecting a plurality of batteries in series. In addition, a plurality of batteries may be connected in parallel to form a battery pack according to the charge / discharge capacity required for the battery pack. Accordingly, the number of batteries included in the battery pack and the form of electrical connection can be set differently according to the required output voltage and / or charge / discharge capacity.Here, cylindrical, rectangular and pouch type batteries are known as secondary battery types. In the case of a cylindrical battery, a separator serving as an insulator is interposed between a positive electrode and a negative electrode, and they are wound to form an electrode assembly in the form of a jelly roll which is inserted into a battery case together with an electrolyte to form a battery. In addition, a strip-shaped electrode tab may be connected to an uncoated portion of both the positive electrode and the negative electrode, and the electrode tab electrically connects the electrode assembly and an electrode terminal exposed to the outside. For comparison, in a cylindrical battery having a shape factor of 1865, 2170, or the like, the positive electrode terminal is a cap of a sealing body that closes (seals) the opening of the battery case, and the negative electrode terminal is the battery case.However, according to the conventional cylindrical battery, since current is concentrated in the strip-shaped electrode tab coupled to the uncoated portion of the positive electrode and / or the uncoated portion of the negative electrode, the current collection efficiency is not good due to the large resistance and the large heat generation.In small cylindrical batteries having a shape factor of 1865, a shape factor of 2170, or the like, resistance and heat are not a great problem. However, if the form factor is increased to apply the cylindrical battery to an electric vehicle, the cylindrical battery may ignite when much heat is generated around the electrode tab during the rapid charging process.To solve this problem, a cylindrical battery (so-called tabless cylindrical battery) is provided in which the uncoated positive electrode portion and the uncoated negative electrode portion are configured to be positioned at the top and the bottom of the jelly roll electrode assembly, respectively, and the current collector is welded to the uncoated portion to improve current collection efficiency.FIGS. 1 ato 1 care diagrams showing a process for manufacturing a tabless cylindrical battery. FIG. 1 ashows the structure of an electrode, FIG. 1 bshows a process for winding the electrode, and FIG. 1 cshows a process for welding a current collector to a bent surface of an uncoated portion. FIG. 1 dis a cross-sectional view showing the tabless cylindrical battery along the longitudinal direction Y.Referring to FIGS. 1 ato 1 d, a positive electrode 10 and a negative electrode 11 have a structure in which a sheet-shaped current collector 20 is coated with an active material 21, and have an uncoated portion 22 on a long side along the winding direction X.An electrode assembly A is produced by successively stacking the positive electrode 10 and the negative electrode 11 together with two sheets of separators 12 as shown in FIG. 1 b, and then winding them in a direction X. At this time, the uncoated portions of the positive electrode 10 and the negative electrode 11 are arranged in opposite directions.After the winding process, the uncoated portion 10 aof the positive electrode 10 and the uncoated portion 11 aof the negative electrode 11 are bent toward the core. Thereafter, current collectors 30, 31 are welded and coupled to the uncoated portions 10 a, 11 a, respectively.An electrode tab is not separately coupled to the positive electrode uncoated portion 10 aand the negative electrode uncoated portion 11 a, the current collectors 30, 31 are connected to external electrode terminals, and a current path is formed with a large cross-sectional area along the winding axis direction of the electrode assembly A (see arrow), which has an advantage of reducing the resistance of the battery. This is because the resistance is inversely proportional to the cross-sectional area of the path through which the current flows.The electrode assembly A is inserted into the battery case 32. The current collector 31 is welded to the lower surface of the battery case 32. At the upper portion of the edge of the current collector 31, the outer peripheral surface of the battery case 32 is press-fitted to form the bead portion 33. The inner surface of the bead portion 33 presses the edge of the current collector 30, and as a result, the electrode assembly A is firmly fixed inside the battery case 32.After the electrode assembly A is fixed inside the battery case 32, electrolyte is injected into the battery case 32. Thereafter, the cap assembly 34 is coupled to the open portion of the battery case 32.The cap assembly 34 may include a cap 34 a, a connection plate 34 ccoupled to the lower portion of the cap 34 a, and a seal 34 bthat closes (seals) the periphery of the cap 34 aand the open portion of the battery case 32.The upper portion of the bead portion 33 includes a crimping portion 35. the crimping portion 35 is formed by bending the open portion of the battery case 32 inward and closes (and seals) the open portion of the battery case 32 by pressing the packing 34 btoward the peripheral surface of the cap 34 a.The current collector 30 and the connection plate 34 cmay be electrically connected by a lead 30 a. The lead 30 amay be manufactured as a separate part and connected to the current collector 30, or may be manufactured and elongated integrally with the current collector 30 and coupled to the connection plate 34 c.An insulator 36 is disposed on the upper portion of the current collector 30. The edge of the insulator 36 may be disposed between the bead portion 33 and the current collector 30. Accordingly, the bead portion 33 presses the electrode assembly A toward the bottom of the battery case 32 through the insulator 36.Meanwhile, as the charge and discharge cycle of the cylindrical battery 37 increases, a swelling phenomenon occurs and the internal pressure increases. The swelling phenomenon refers to a phenomenon in which the volume of the active material coated on the positive electrode 10 and the negative electrode 11 increases as the charging and discharging are repeated. The degree of swelling is relatively larger on the negative electrode 11. A cavity exists in the core of the electrode assembly A, which is formed by the winding process as a trace of the core member inserted therein. Therefore, as the internal pressure of the cylindrical battery 37 increases due to the swelling phenomenon, a voltage is concentrated toward the core of the electrode assembly A. Since the battery case is made of a high strength metal, most of the stress is concentrated toward the core of the electrode assembly A where an empty space exists.When a voltage occurs in the electrode assembly A due to the swelling phenomenon, the voltage also acts in the circumferential direction, so that the positive electrode 10 and the negative electrode 11 slightly rotate while sliding with the separator interposed therebetween. In addition, as the charge and discharge cycle increases, the amount of rotation of the positive electrode 10 and the negative electrode 11 accumulates to generate a fine gap between the positive electrode 10 and the negative electrode 11 in the vicinity of the core, thereby causing a local change in the curvature. Therefore, even if the electrode assembly A has good symmetry and circularity immediately after winding, when the swelling phenomenon occurs, the symmetry and circularity of the electrode assembly A change as opposed to the first time.In addition, when the swelling phenomenon is enhanced in a state in which the symmetry and circularity of the electrode assembly A are changed, a portion of the core of the electrode assembly A cannot resist the voltage but may collapse. In this process, the separator is torn off in the vicinity of the collapse region or fine cracks are generated in the electrode, causing an internal short circuit, which is indicated as a main cause of ignition accidents within the cylindrical battery.FIGS. 2 ato 2 care cross-sectional views of the electrode assembly A schematically showing the process in which the core of the electrode assembly A collapses. Each cross-sectional view shows a plane cut perpendicular to the axial direction of the electrode assembly A.FIG. 2 ashows the core structure of the electrode assembly A when the cylindrical battery 37 is in the BOL state (beginning of life). Since a step is formed at the ends of the negative electrode and the positive electrode, circularity in the vicinity of the ends is reduced. In addition, when straight lines L 1 and L 2 are drawn from the center of the core through the positive electrode end and the negative electrode end, respectively, the winding turns of the electrodes located between L 1 and L 2 along the circumferential direction are not constant in curvature but change.FIG. 2 bshows a state in which the volume of the electrode, in particular the negative electrode, increases as the charging and discharging cycle for the cylindrical battery 37 proceeds a plurality of times, so that the negative and positive electrodes are rotated in the vicinity of the core. The volume change of the negative electrode is the greatest at the first charge during the activation process for the cylindrical battery 37. This is because the chemicals causing the electrochemical reaction move from the positive electrode to the negative electrode and are inserted into the negative electrode.The core of the electrode assembly A has a recess. Therefore, the rotation of the electrode mainly occurs in the core. Of course, the electrode rotates slightly in the outer periphery of the electrode assembly A, but the degree of rotation is not significant as compared to the core side. This is because a recess exists in the core of the electrode assembly A, so that when a rotational stress occurs, the rotational freedom of the electrode is greater at the core than at the outer periphery of the electrode assembly A.The volume increase of the negative electrode is relatively larger than that of the positive electrode. In addition, near the core of the electrode assembly A, the positive electrode is disposed between the winding turns of the negative electrode, so that a relatively larger frictional force acts on the surface of the positive electrode than on the surface of the negative electrode. Therefore, the rotation amount of the negative electrode is larger than the rotation amount of the positive electrode. This is because the larger the volume increase, the more rotational stress occurs, and the smaller the frictional force, the more sliding occurs. In FIG. 2 b, the rotation of the positive and negative electrodes can be found from the fact that the core-side ends of the positive and negative electrodes rotate clockwise. The direction in which the electrode end rotates in the core of the electrode assembly is opposite to the winding direction.Fig. 2c shows the core structure when the swelling phenomenon increases as the charging and discharging cycle for the cylindrical battery 37 proceeds hundreds times. Due to the increase of the swelling phenomenon, the end of the negative electrode rotates to the point where the end of the positive electrode is located. As a result, the core portion collapsed. When the core collapses, the structure of the winding turn having an outwardly convex arc shape, such as the winding turns of the electrode, which are in the direction of 3 o'clock to 6 o'clock, is converted into a shape that is convex toward the core.When the core of the electrode assembly A collapses, as shown in FIG. 2 c, the close contact between the positive electrode 10 and the negative electrode 11 is not maintained, a fine gap occurs at the interface between the electrodes, and the battery capacity suddenly decreases. In addition, the electrode and the separator near the collapse portion collapse toward the core, causing the separator to crack or a fine crack to occur in the electrode, and thus the positive electrode 10 and the negative electrode 11 may contact each other, causing an internal short circuit.The collapse of the core of the electrode assembly A becomes more severe as the diameter of the electrode assembly A increases. This is because as the diameter of the electrode assembly A increases, the rotational force in the circumferential direction caused by the increase in the electrode volume further increases. Therefore, when manufacturing large-diameter cylindrical batteries having a shape factor of 4680 (diameter: 46 mm, height: 80 mm), a special construction is required to prevent the core of the electrode assembly from collapsing.DISCLOSURETechnical TaskThe present disclosure has been developed to solve the problems of the related art. The rotation of positive and negative electrodes due to the swelling phenomenon of a cylindrical battery influences the symmetry and circularity of an electrode assembly. Therefore, in order to prevent the core of the electrode assembly from collapsing, it is necessary to make optimum the relative positions of the positive and negative electrodes within the electrode assembly by considering the rotation of the positive and negative electrodes.The present disclosure is directed to deriving a structural configuration capable of preventing the core from collapsing by maintaining the symmetry and circularity of the core of the electrode assembly even when a swelling phenomenon occurs by adjusting relative positions of a positive electrode end and a negative electrode end on the core and the outer periphery of the electrode assembly when a cylindrical battery is manufactured.The present disclosure is also directed to providing a cylindrical battery including an electrode assembly optimally designed to improve the collapse phenomenon of the core, and a battery pack and a vehicle including the same.The technical objects of the present disclosure are not limited to the above, and other objects and advantages of the present disclosure can be understood from the following detailed description and become more apparent from the exemplary embodiments of the present disclosure. It is also readily understood that the objects and advantages of the present disclosure may be realized by the means shown in the appended claims and combinations thereof.Technical SolutionIn an aspect of the present disclosure, there is provided a cylindrical battery including: an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound with respect to a winding axis to define a core and an outer periphery; and a cylindrical battery case configured to house the electrode assembly.On a cross section of the electrode assembly perpendicular to the winding axis direction, a first fan-shaped region surrounded by a first straight line and a second straight line passing from a center of the core through a core-side end of the first electrode and a core-side end of the second electrode, respectively, and the outer periphery may be defined as a stress-prone region, and a second fan-shaped region surrounded by a third straight line and a fourth straight line passing from the center of the core through an outer periphery-side end of the first electrode and an outer periphery-side end of the second electrode, respectively, and the outer periphery may be defined as a stress-strengthening region.The electrode assembly may have a winding structure in which, of the voltage enhancing portion, at least the outer peripheral side end of the first electrode is spaced apart from the inside of the voltage prone portion along a circumferential direction.The electrode assembly may have a winding structure in which the voltage enhancing region is spaced apart from the voltage susceptible region along the circumferential direction on the cross section.A portion of the outer periphery of the electrode assembly where the outer peripheral side end of the first electrode is located may be in close contact with an inner surface of the battery case.The position of the outer circumferential side end of the first electrode may be substantially fixed while the cylindrical battery is being repeatedly charged and discharged.On the cross section, the cross section may be classified into a first semicircular region and a second semicircular region based on a diametrical line segment that passes through the center of the core and is perpendicular to a straight line that divides a circumferential angle of the stress-susceptible region into two equal angles.The electrode assembly may have a winding structure in which the voltage-prone region is located in the first semicircular region and the voltage-boosting region is located in the second semicircular region.The electrode assembly may have a winding structure in which at least a part of the voltage enhancing portion overlaps with a third fan-shaped portion in the second semicircular portion that is point-symmetric with the voltage susceptible portion with respect to the center of the core.The electrode assembly may have a winding structure in which at least a part of the voltage boosting region overlaps with a fifth straight line that divides a circumferential angle of the third fan-shaped region into equal angles.When a straight line sharing a third fan-shaped region which is point-symmetric with the stress-prone region with respect to the center of the core is a fifth straight line, the electrode assembly may have a winding structure in which the third straight line and the fourth straight line are located between the second straight line and the fifth straight line with respect to the circumferential direction on the cross section.When a straight line sharing a third fan-shaped region which is point-symmetric with the stress-prone region with respect to the center of the core is a fifth straight line, the electrode assembly may have a winding structure in which the third straight line and the fourth straight line are located between the first straight line and the fifth straight line with respect to the circumferential direction on the cross section.When a straight line sharing a third fan-shaped region which is point-symmetric with the stress-prone region with respect to the center of the core is a fifth straight line, the electrode assembly may have a winding structure in which the fourth straight line is located between the fifth straight line and the first straight line and the third straight line is located between the fourth straight line and the second straight line with respect to the circumferential direction on the cross section.When a straight line sharing a third fan-shaped region which is point-symmetric with the stress-prone region with respect to the center of the core is a fifth straight line, the electrode assembly may have a winding structure in which the fourth straight line is located between the fifth straight line and the first straight line and the third straight line is located between the fifth straight line and the second straight line with respect to the circumferential direction on the cross section.When a straight line sharing a third fan-shaped region which is point-symmetric with the stress-prone region with respect to the center of the core is a fifth straight line, the electrode assembly may have a winding structure in which the fourth straight line is located between the fifth straight line and the second straight line and the third straight line is located between the fourth straight line and the first straight line with respect to the circumferential direction on the cross section.When a straight line sharing a third fan-shaped region which is point-symmetric with the stress-prone region with respect to the center of the core is a fifth straight line, the electrode assembly may have a winding structure in which the fourth straight line is located between the fifth straight line and the second straight line and the third straight line is located between the fifth straight line and the first straight line with respect to the circumferential direction on the cross section.The electrode assembly may have a winding structure in which a circumferential angle between the first straight line and the fourth straight line is larger than a circumferential angle between the second straight line and the third straight line with respect to the circumferential direction on the cross section.The electrode assembly may have a winding structure in which a circumferential angle between the second straight line and the fourth straight line is larger than a circumferential angle between the first straight line and the third straight line with respect to the circumferential direction on the cross section.The electrode assembly may have a winding structure in which a circumferential angle of the voltage boosting portion is smaller than a circumferential angle of the voltage susceptible portion with respect to the center of the core.The winding structure of the electrode assembly as described above may be maintained during charging and discharging for 200 cycles or more, 300 cycles or more, 400 cycles or more, 500 cycles or more, 600 cycles or more, 700 cycles or more, 800 cycles or more, or 900 cycles or more.One cycle may include a full charge and a full discharge. Full charge means a charge that increases the SOC of a cylindrical battery from 0% to 100%. Full discharge means discharge that reduces the SOC of a cylindrical battery from 100% to 0%. The magnitude of the charging current and the charging temperature of the full charge may be selected according to the effective operating conditions of the cylindrical battery. Likewise, the magnitude of the discharge current and the discharge temperature for the full discharge can be selected from the effective operating conditions of the cylindrical battery.The first electrode and the second electrode may be a positive electrode and a negative electrode, respectively. At least a part of winding turns of the negative electrode formed only by the second electrode may be provided adjacent to the core side. A winding turn in which at least a part of the negative electrode winding turns faces in a radial direction may be the negative electrode winding turn.A plurality of winding turns formed only by the separator may be provided on an inner side of the negative electrode winding turn.The first electrode and the second electrode may be a positive electrode and a negative electrode, respectively. The core-side end of the second electrode may extend further in a direction opposite to the winding direction than the core-side end of the first electrode to form at least a part of the innermost winding turn. The outer circumferential side end of the second electrode may extend further in the winding direction than the outer circumferential side end of the first electrode to form at least a part of the outermost winding turn.The electrode assembly may have a winding structure in which a circumferential angle of the stress-prone portion has an angle of 30 degrees or more and less than 180 degrees and a circumferential angle of the stress enhancing portion has an angle of 10 degrees or more and 90 degrees or less.The electrode assembly may have a winding structure in which the circumferential angle of the stress-prone portion has an angle of 87 degrees or more and the circumferential angle of the stress-enhancing portion has an angle of 32 degrees or less.The battery case may have an open end and a bottom portion opposite thereto, accommodate the electrode assembly in the space between the open end and the bottom portion, and be electrically connected to one of the first electrode and the second electrode to have a first polarity.The cylindrical battery may further include a seal body configured to (tightly) close the open end of the battery case; and a terminal electrically connected to the other of the first electrode and the second electrode to have a second polarity, and having a surface exposed to the outside.The first electrode may have a first uncoated portion at a long side end along a winding direction of the electrode assembly.The second electrode may have a second uncoated portion at a long side end along the winding direction.The first uncoated portion may extend from the separator through an end of the electrode assembly and protrude outward and be bent in a radial direction of the electrode assembly to form a first bending surface area. The first uncoated section may include a plurality of segments separated by cut grooves. The plurality of segments may be arranged along the winding direction of the electrode assembly. The first bending surface area may be formed by bending the plurality of segments along the radial direction of the electrode assembly.The second uncoated portion may extend from the separator through the other end of the electrode assembly and project outward and be bent toward the core to form a second bending surface area. The second uncoated section may have multiple segments separated by cut grooves. The plurality of segments may be arranged along the winding direction of the electrode assembly. The second bending surface portion may be formed by bending the plurality of segments along the radial direction of the electrode assembly.The cylindrical battery may further include a first current collector welded to the first bending surface area; and / or a second current collector welded to the second bending surface area.The welding region of the first current collector and / or the second current collector may have a radial structure with respect to the center of the core of the electrode assembly.The welding structure between the first bending surface portion and the first current collector and / or the welding structure between the second bending surface portion and the second current collector may work synergistically with the above-described winding structure of the electrode assembly to prevent the electrode from rotating while the cylindrical battery is being charged and discharged.The battery may have a diameter to height ratio of greater than 0.4.The battery may have a form factor of 46110, 4875, 48110, 4880, 4680 or 4695.In another aspect of the present disclosure, there is also provided a vehicle including the battery pack including a plurality of cylindrical batteries as described above.Advantageous EffectsAccording to an embodiment of the present disclosure, it is possible to prevent the core from collapsing by maintaining the symmetry and circularity of the electrode assembly even when a swelling phenomenon occurs by adjusting relative positions of a positive electrode end and a negative electrode end on the core and the outer periphery of the electrode assembly of the cylindrical battery.According to another embodiment of the present disclosure, it is possible to provide a cylindrical battery including an electrode assembly having a structure capable of improving the collapse phenomenon of the core.According to still another embodiment of the present disclosure, a battery pack manufactured using the cylindrical battery having an improved structure and a vehicle including the same may be provided.In addition to the above effects, specific effects of the present disclosure will be described below, while the specific details for carrying out the present disclosure will be explained.DESCRIPTION OF THE DRAWINGSThe accompanying drawings illustrate a preferred embodiment of the present disclosure and together with the above disclosure serve to provide further understanding of the technical features of the present disclosure, and thus the present disclosure is not construed as being limited to the drawings. FIG. 1a is a plan view showing a structure of an electrode used for a conventional tabless cylindrical battery. FIG. 1 bis a diagram showing a process for winding an electrode assembly included in the conventional tabless cylindrical battery. FIG. 1 cis a diagram showing a process of welding a current collector to a bent surface of an uncoated portion in the electrode assembly of FIG. 1 b. FIG. 1 dis a cross-sectional view showing the conventional tabless cylindrical battery along the axial direction Y. FIGS. 2 ato 2 care cross-sectional views schematically showing the process in which the core of the electrode assembly collapses in the conventional cylindrical battery. FIG. 3 is a cross-sectional view showing a cylindrical battery according to an embodiment of the present disclosure perpendicular to the axial direction Y. FIG. 4 is a diagram for illustrating the relative positional relationship between a stress-prone region D 1 and a stress-enhancing region D 2 according to an embodiment of the present disclosure. FIG. 5 ais a diagram showing relative positions of a core-side end (A inner) and an outer circumferential-side end (A outer) of the negative electrode, and a core-side end (B inner) and an outer circumferential-side end (B outer) of the positive electrode B according to an embodiment of the present disclosure. FIG. 5 bis a diagram showing relative positions of a core-side end (A inner) and an outer circumferential-side end (A outer) of the negative electrode, and a core-side end (B inner) and an outer circumferential-side end (B outer) of the positive electrode B according to another embodiment of the present disclosure. FIG. 5 cis a diagram showing relative positions of a core-side end (A inner) and an outer circumferential-side end (A outer) of the negative electrode, and a core-side end (B inner) and an outer circumferential-side end (B outer) of the positive electrode B according to still another embodiment of the present disclosure. FIG. 6 ais a diagram showing cross sections of three electrode assemblies in which recesses provided in the core of the electrode assembly JR have different diameters according to an embodiment of the present disclosure. FIG. 6 bis a graph comparatively showing the degree of deformation of the winding turn near the core when cylindrical batteries including three electrode assemblies shown in FIG. 6 aare repeatedly charged and discharged. FIG. 7 ais a CT cross-sectional photograph taken when the #1 sample battery is in the BOL state (beginning of life). FIG. 7 bis a CT cross-sectional photograph taken after 200 cycle tests were performed on the #1 sample battery. FIG. 7 cis a CT cross-sectional photograph taken after 300 cycle tests were performed on the #1 sample battery. FIG. 8a is a CT cross-sectional photograph taken when the #2 sample battery is in the BOL state. FIG. 8 bis a CT cross-sectional photograph taken after 900 cycle tests were performed on the #2 sample battery. FIG. 9 is a graph showing the results of measuring the rotation amount of the negative electrode core side end (A inner) and the positive electrode core side end (B inner) while repeating the cycle test for the #2 sample battery immediately after the production. FIG. 10 ais a CT cross-sectional photograph taken when the #3 sample battery is in the BOL state. FIG. 10 bis a CT cross-sectional photograph taken after 900 cycle tests were performed on the #3 sample battery. FIG. 11 ais a CT cross-sectional photograph taken when the #4 sample battery is in the BOL state. FIG. 11 bis a CT cross-sectional photograph taken after 700 cycle tests were performed on the #4 sample battery. FIG. 12 ais a CT cross-sectional photograph taken when the #5 sample battery is in the BOL state. FIG. 12 bis a CT cross-sectional photograph taken after 420 cycle tests were performed on the #5 sample battery. FIG. 13 ais a CT cross-sectional photograph taken when the #6 sample battery is in the BOL state. FIG. 13 bis a CT cross-sectional photograph taken after 420 cycle tests were performed on the #6 sample battery. FIG. 14 ais a plan view showing a structure of an electrode according to the first embodiment of the present disclosure. FIG. 14 bis a plan view showing the structure of an electrode according to the second embodiment of the present disclosure. FIG. 14 cis a plan view showing the structure of an electrode according to the third embodiment of the present disclosure. FIG. 14 dis a plan view showing the structure of an electrode according to the fourth embodiment of the present disclosure. FIG. 1, FIG. 4 eis a diagram showing the definitions of width, height, and separation distance of a segment according to an embodiment of the present disclosure. FIG. 14 fis a diagram showing an arc formed by a lower end of the segment, the width of the segment being defined with respect to the center of the core of the electrode assembly when the electrode is wound, according to an embodiment of the present disclosure. FIG. 14 g is a diagram schematically showing the relationship between heights h 1, h 2, h 3, h 4 of segments, core radius rc, and radii r 1, r 2, r 3, r 4 of winding turns where segments start to appear, according to an embodiment of the present disclosure. FIG. 14 his a conceptual diagram for determining a maximum value (hmax) for the height (H) of the segment in a variable segment height range. FIG. 14 iis a schematic diagram for explaining the formula that determines a lower angle (θ) of the segment. FIG. 14 jis a plan view showing a modified structure of the electrode according to the fourth embodiment of the present disclosure. FIG. 14 k is a top plan view showing an independent area in which a plurality of segments may be located when the electrode is wound into an electrode assembly according to a modification of the present disclosure. FIG. 15 ais a plan view showing the structure of an electrode according to the fifth embodiment of the present disclosure. FIG. 15 bis a diagram showing the definitions of width, height, and separation distance of a segment according to another embodiment of the present disclosure. FIG. 15 cis a plan view showing a modified structure of the electrode according to the fifth embodiment of the present disclosure. FIG. 16 is a diagram showing a segment structure according to various modifications of the present disclosure. FIG. 17 ais a schematic diagram showing a cross section of a bending surface portion formed by bending the segment toward the core of the electrode assembly. FIG. 17 bis a perspective plan view schematically showing an electrode assembly in which the bending surface portion is formed. FIG. 17 care graphs showing the results of counting the number of stacks of segments along a radial direction in the positive electrode bending surface area formed at the upper portion of the electrode assemblies according to Embodiments 1-1 to 1-7 and the comparative example. FIG. 17 dare graphs showing the results of counting the stack number of segments along the radial direction in the positive electrode bending surface area formed at the upper portion of the electrode assemblies according to Embodiments 2- 1 to 2- 5, Embodiments 3- 1 to 3- 4, Embodiments 4- 1 to 4- 3, and Embodiments 5- 1 to 5- 2. FIG. 17 eare graphs showing the results of counting the stack number of segments along the radial direction in the positive electrode bending surface area formed at the upper portion of the electrode assembly according to Embodiments 6- 1 to 6- 6 and Embodiments 7- 1 to 7- 6. FIG. 17 fis a top plan view of the electrode assembly showing a uniform stack number range b 1 and a decreasing stack number range b 2 in the bending surface area of the segment according to an embodiment of the present disclosure. FIG. 18 is a cross-sectional view of a jelly roll type electrode assembly in which the electrode of the first embodiment is applied to a first electrode (positive electrode) and a second electrode (negative electrode) along the Y-axis direction (winding axis direction). FIG. 19 is a cross-sectional view of a jelly roll type electrode assembly in which an electrode of the second embodiment is applied to the first electrode (positive electrode) and the second electrode (negative electrode) along the Y-axis direction (winding axis direction). FIG. 20 is a cross-sectional view of a jelly roll type electrode assembly in which any one of the electrodes of the third to fifth embodiments (modifications thereof) is applied to the first electrode (positive electrode) and the second electrode (negative electrode) along the Y-axis direction (winding axis direction). FIG. 21 is a cross-sectional view of an electrode assembly according to still another embodiment of the present disclosure along the Y-axis direction (winding axis direction). FIG. 22 is a cross-sectional view of an electrode assembly according to still another embodiment of the present disclosure along the Y-axis direction (winding axis direction). FIG. 23 is a cross-sectional view of an electrode assembly according to still another embodiment of the present disclosure along the Y-axis direction (winding axis direction). FIG. 24 is a sectional view showing a cylindrical battery according to an embodiment of the present disclosure along the Y-axis direction. FIG. 25 is a sectional view showing a cylindrical battery according to another embodiment of the present disclosure along the Y-axis direction. FIG. 26 is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure along the Y-axis direction. FIG. 27 is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure along the Y-axis direction. FIG. 28 is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure along the Y-axis direction. FIG. 29 is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure along the Y-axis direction. FIG. 30 is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure along the Y-axis direction. FIG. 31 is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure along the Y-axis direction. FIG. 32 is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure along the Y-axis direction. FIG. 33 is a plan view showing a structure of a first current collector according to an embodiment of the present disclosure. FIG. 34 is a plan view showing a structure of a second current collector according to an embodiment of the present disclosure. FIG. 35 is a plan view showing a state in which a plurality of cylindrical batteries are electrically connected. FIG. 36 is a partially enlarged view of FIG. 35. FIG. 37 is a diagram schematically showing a battery pack according to an embodiment of the present disclosure. FIG. 38 is a diagram schematically showing a vehicle including the battery pack according to an embodiment of the present disclosure.BEST EMBODIMENTThe above purpose, features, and advantages will be described in detail later with reference to the accompanying drawings, and accordingly, a person skilled in the technical field to which the present disclosure pertains will be able to easily realize the technical spirit of the present disclosure. When it is assumed in the explanation of the present disclosure that a detailed description of the publicly known technology related to the present disclosure may unnecessarily obscure the gist of the present disclosure, the detailed explanation is omitted. Hereinafter, a preferred embodiment according to the present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, identical reference numerals are used to indicate identical or similar components.Although the terms first, second, or the like are used to describe different elements, these elements are not limited by the terms. These terms are used to distinguish one element from another, and unless otherwise stated, a first element may be a second element.Throughout the specification, unless otherwise indicated, each element may be singular or plural.Hereinafter, when an element is located "above (or below)" or "on (or below)" another element, the element may be located on an upper surface (or a lower surface) of the other element, and intermediate elements may be present between the element and the other element on (or below) the element.Additionally, when an element is referred to as being "connected," "coupled," or "associated" with another element, the element may be directly connected or coupled to the other element, however, it is understood that intervening elements may be present between each element, or each element may be "connected," "coupled," or "associated" by another element.Singular terms used in this specification include plural terms unless the context clearly indicates otherwise. In this application, terms such as "including" or "having" should not be construed as necessarily including all of the various components or steps described in the specification, and it should be construed that some of the components or some of the steps may not be included or additional components or steps may be further included.Furthermore, singular terms used in this specification include plural terms unless the context clearly indicates otherwise. In this application, terms such as "including" or "having" should not be construed as necessarily including all of the various components or steps described in the specification, and it should be construed that some of the components or some of the steps may not be included or additional components or steps may be further included.Throughout the specification, "A and / or B" refers to either A or B or both A and B, unless expressly stated otherwise, and "C to D" refers to C or greater and D or less, unless expressly stated otherwise.For convenience of description, a direction that extends along a longitudinal direction of a winding axis of an electrode assembly wound in a roll shape is referred to herein as an axis direction Y. In addition, a direction about the winding axis is referred to herein as a circumferential direction X. In addition, a direction approaching or away from the winding axis is referred to as a radial or radiation direction Z. Among them, specifically, the direction approaching the winding axis is referred to as a centripetal direction, and the direction away from the winding axis is referred to as a centrifugal direction.Hereinafter, a preferred embodiment of the present disclosure will be described with reference to the accompanying drawings.FIG. 3 is a cross-sectional view showing a cylindrical battery according to an embodiment of the present disclosure perpendicular to the axial direction Y.Referring to FIG. 3, the electrode assembly JR according to the embodiment has a jelly roll structure in which a negative electrode A and a positive electrode B are wound around an axis with a separator S interposed therebetween. In one embodiment, the positive electrode B may be the first electrode and the negative electrode A may be the second electrode, or vice versa. The winding direction X is a counterclockwise direction, but may be replaced with a clockwise direction. When the winding direction X is a clockwise direction, it is obvious that the rotation direction of the electrode described below can be reversed.A recess is formed in the core C of the electrode assembly JR. The depression is an empty space. Alternatively, a center pin used in the process of winding the electrode assembly JR may be disposed in the recess. There are two separators S as indicated by dotted lines and broken lines, respectively. The arrangement structure of the separators S may be modified in various ways as long as they can isolate the negative electrode A and the positive electrode B from each other.The winding structure of the negative electrode A, the positive electrode B, and the separator S in the electrode assembly JR is schematically shown. In the actual winding structure of the electrode assembly JR, the negative electrode A, the positive electrode B, and the separator S are in close contact with each other.The negative electrode A and / or the positive electrode B may have a structure in which an electrode tab is not separately attached thereto as shown in FIGS. 14 ato 14 dand 15 a. The present disclosure is effective in preventing or mitigating the collapse of the core of the electrode assembly JR having a structure in which the negative electrode A and / or the positive electrode B does not separately include an electrode tab. However, the present disclosure may also be applied without limitation to embodiments in which the negative electrode A and / or the positive electrode B include a separate electrode tab.To prevent core collapse, a structure is disclosed in which the electrode construction (e.g., electrode end position, core diameter, etc.) of an electrode assembly is disclosed in which an electrode tab is not separately coupled to the uncoated electrode portion.In the electrode assembly JR, the negative electrode A has a longer length in the winding direction X than the positive electrode B.The winding turn of the negative electrode A starts before the winding turn of the positive electrode B. The winding turn of the positive electrode B starts after the winding turn of the negative electrode A increases by a predetermined number of turns. The predetermined number of turns may be less than 1 or 1 or more. In one example, the winding turn of the negative electrode A that does not face the positive electrode B may be 0.5 to 5 turns. The winding turns in the vicinity of the core C where only the negative electrode A is wound reinforce the structural rigidity of the core. However, the winding turn formed only by the negative electrode A does not contribute to the capacity of the cylindrical battery. Therefore, the number of winding turns only for the negative electrode A can be appropriately selected in consideration of the gain of the structural rigidity and the capacitance. The winding turn in the vicinity of the core C where only the negative electrode A is wound may face the winding turn of the adjacent negative electrode in the radial direction. Although not shown, a plurality of winding turns formed only by the separator S may be provided within the winding turn formed only by the negative electrode A, as shown in FIG. 2 b. The winding turn formed only by the separator S may also reinforce the structural rigidity of the core.The present disclosure discloses a structure that optimizes the end positions of the negative electrode A and the positive electrode B to prevent the core from collapsing due to torsional stress resulting from the swelling phenomenon.The ends of the negative electrode A and the positive electrode B refer to a core-side end and an outer circumferential-side end of the winding winding winding structure of the negative electrode A and the positive electrode B. Preferably, the core-side end and the outer circumferential-side end may be the ends of the active material layer in the winding direction of the electrode assembly JR. Alternatively, the core-side end and the outer peripheral-side end may be the ends of the current collector coated with an active material layer. As another alternative, the core-side end and the outer circumferential-side end may be the ends of the current collector that are not coated with an active material layer.In the present disclosure, for convenience of explanation, an embodiment in which the end positions of the negative electrode A and the positive electrode B are optimized by applying a two-dimensional polar coordinate system to a cross section perpendicular to the axial direction of the electrode assembly JR will be described.When a two-dimensional polar coordinate system is applied to the cross-sectional structure of the electrode array JR, the position within the cross-sectional structure may be expressed as a distance (r) measured from the center of the polar coordinate system to the corresponding position and an angle measured to the corresponding position in the circumferential direction (counterclockwise) with respect to a coordinate (z-axis).Even when the angle measurement direction of the position is changed to the clockwise direction, the technical idea of the present disclosure can be applied practically in the same manner.Referring to FIG. 3, the angle of the core side end (A inner) and the angle of the outer peripheral side end (A outer) of the negative electrode A may be expressed as θ A,inner and θ A,outer respectively.Similarly, the angle of the core side end (B inner) and the angle of the outer peripheral side end (B outer) of the positive electrode B may be expressed as θ B,inner and θ B,outer respectively.The core-side end (A inner) of the negative electrode A may extend further in the direction opposite to the winding direction than the core-side end (B inner) of the positive electrode B to form at least a part of the innermost winding turn. In addition, the outer circumferential side end (A outer) of the negative electrode A may extend further in the winding direction than the outer circumferential side end (B outer) of the positive electrode B to form at least a part of the outermost winding turn.According to one aspect, when the negative electrode A and the positive electrode B are wound counterclockwise, when the charge and discharge cycle is repeated, the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B rotate clockwise.The amount of rotation is relatively larger when the initial cycle is performed than when the subsequent use cycle is performed.The initial cycle refers to the first charge that increases the SOC of the cylindrical battery to a preset level by performing an activation process after the cylindrical battery including the electrode assembly JR is manufactured. The usage cycle following the activation process includes a full discharge that decreases the cylindrical battery SOC to 0% and a full charge that increases the cylindrical battery SOC to 100%.When the usage cycle is repeatedly performed, the amount of rotation of the negative electrode A and the positive electrode B may linearly increase as the usage cycle increases. When the number of use cycles increases beyond a criterion value, the rotation amount may gradually decrease and converge to 0.The swelling amount of the negative electrode A is relatively larger than that of the positive electrode B. Moreover, since the innermost part of the electrode assembly JR includes winding turns formed only by the negative electrode A, the freedom of rotation is higher than that of the positive electrode B. In addition, the core-side end (B inner) of the positive electrode B is disposed between the winding turns of the negative electrode A, so that the frictional force in this region is high. Therefore, the rotation amount of the core side end (A inner) of the negative electrode A is larger than the rotation amount of the core side end (B inner) of the positive electrode B.In one example, the amount of rotation of the core-side end (A inner) of the negative electrode A may be several tens of degrees, and the amount of rotation of the core-side end (B inner) of the positive electrode B may be less than ten degrees.The outer peripheral side end (A outer) of the negative electrode A and the outer peripheral side end (B outer) of the positive electrode B slightly rotate counterclockwise as the initial cycle proceeds. As the initial cycle proceeds, a portion of the outer periphery of the electrode assembly JR corresponding to the outer peripheral side end (B outer) of the positive electrode B comes into close contact with the inner surface of the container. Therefore, when the use cycle is repeated after the initial cycle, the outer peripheral side end (A outer) of the negative electrode A and the outer peripheral side end (B outer) of the positive electrode B do not rotate to a reasonable level due to the anchoring effect. Therefore, the angle between the outer peripheral side end (A outer) of the negative electrode A and the outer peripheral side end (B outer) of the positive electrode B does not significantly change due to the anchoring effect as the use cycle proceeds after the initial cycle.According to another aspect, on the cross section of the electrode assembly JR, the winding turn part included in the first fan-shaped region surrounded by a first straight line (L B,inner) surrounded from the center of the core C by the core-side end (B inner) of the positive electrode B, a second straight line (L A,inner), surrounded from the center of the core C by the core-side end (A inner) of the negative electrode A, and the outer periphery of the electrode assembly JR has deteriorated circularity near the core C and is therefore susceptible to stress applied to the core C, when the electrode arrangement JR swells.According to still another aspect, on a cross section of the electrode assembly JR, the winding turn part included in the second fan-shaped region surrounded by a third straight line (L B,outer) passes from the center of the core C through the outer circumferential side end (B outer) of the positive electrode B, a fourth straight line (L A,outer), passing from the center of the core through the outer circumferential side end (A outer) of the negative electrode A, and the outer circumference of the electrode assembly JR amplifies the stress applied to the core C when the electrode assembly JR swells.This is because the winding turn part where the outer circumferential side end (B outer) of the positive electrode B is located includes most electrode and separator layers in the radial direction, so that when the electrode assembly JR is swelled, the winding turn part where the outer circumferential side end (B outer) of the positive electrode B is located and the outer circumferential side end (A outer) of the negative electrode A adjacent thereto contact the battery case H earlier than other outer circumferential regions and are pressed most, which increases the stress applied to the core C as much due to the action and reaction principle.According to the experiment, the gap between the electrode assembly JR and the battery case H is small, so that as the initial cycle proceeds, the winding turn part where the outer circumferential side end (B outer) of the positive electrode B is located already starts contacting the inner wall of the battery case H. Also, as soon as the winding turn part where the outer peripheral side end (B outer) of the positive electrode B is located starts to contact the battery case H, when the swelling of the electrode assembly JR is depressed, the corresponding winding turn part is more and more pressed toward the inner wall of the battery case H. Therefore, when the cycle of use is repeated, the outer peripheral side end (A outer) of the negative electrode A and the outer peripheral side end (B outer) of the positive electrode B are fixed by the anchoring effect and hardly rotate. Moreover, when the cycle of use is further repeated, the degree of compression at the outer peripheral side end (B outer) of the positive electrode B becomes heavier, so that the corresponding point most enhances the stress according to the action-reaction principle.Hereinafter, for convenience of explanation, the winding turn part included in the first fan-shaped region is defined as a stress-prone region D 1, and the winding turn part included in the second fan-shaped region is defined as a stress-enhancing region D 2.According to still another aspect, the voltage prone portion D 1 and the voltage boosting portion D 2 change their angles and positions while the cylindrical battery is repeatedly charged and discharged after the start of use.As an example, a cylindrical battery may be repeatedly charged and discharged until it reaches an effective use cycle. The effective usage cycle is the total number of cycles in which the loading and unloading can be safely repeated from BOL (Beginning of Life) to EOL (End of Life) required by a customer.The effective cycle of use of a cylindrical battery may be designed in advance depending on its intended use. In an embodiment, the effective usage cycle may be 200 cycles or more, 300 cycles or more, 400 cycles or more, 500 cycles or more, 600 cycles or more, 700 cycles or more, 800 cycles or more, 900 cycles or more, etc.Preferably, the cylindrical battery is configured to stably perform the power even when the full charge and the full discharge are repeated at least at room temperature during preset cycles or more, for example, during the effective use cycles or more. Full charge means charging from the lower limit to the upper limit of the operating voltage, and full discharge means discharging from the upper limit to the lower limit of the operating voltage.When the number of use cycles of a cylindrical battery increases beyond the effective use cycles, the cylindrical battery may be replaced with a new battery, reused for other purposes, or recycled to recover the raw materials contained in the cylindrical battery.Each cycle of the effective use cycles includes a full charge process and a full discharge process. The full charge and the full discharge may be performed at room temperature, for example, 20° C. to 40° C., preferably 20° C. Full charge is a charge that increases the SOC of a cylindrical battery from 0% to 100%. The magnitude of the charging current during full charging may be 1 / 4c to 1 / 3c, preferably 1 / 4c. Full discharge is a discharge that reduces the SOC of a cylindrical battery from 100% to 0%. The magnitude of the discharge current during the full discharge may be 1 / 4c to 1 / 3c, preferably 1 / 3c. Here, the symbol c represents the c rate.According to an aspect, the electrode assembly JR may have a winding structure in which at least the outer circumferential side end (B outer) of the positive electrode B under the voltage enhancing region D 2 is spaced apart from the inner side of the voltage susceptible region D 1 along the circumferential direction on the cross section of the electrode assembly JR. Here, the inside of the voltage boosting region D 2 refers to the inner region except for its boundary.According to another aspect, the electrode assembly JR may have a winding structure in which the voltage boosting region D 2 is spaced apart from the voltage prone region D 1 along the circumferential direction on the cross section of the electrode assembly JR.According to an aspect, the electrode assembly JR may be designed from the beginning to maintain any winding structure defined in the present disclosure while the cylindrical battery is being repeatedly charged and discharged, for example, while the cylindrical battery is being charged and discharged beyond the effective use cycle.In other words, the relative positions of the voltage prone region D 1 and the voltage boost region D 2 can be designed from the beginning by presetting the positions of the core side end (A inner) of the negative electrode A, the core side end (B inner) of the positive electrode B, the outer circumferential side end (Aouter) of the negative electrode A, and the outer circumferential side end (B outer) of the positive electrode B at the winding stage of the electrode assembly JR.In an embodiment, |θ A,inner- θ B,inner|, which corresponds to the circumferential angle between the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B, may be 30 degrees or more and less than 180 degrees.Preferably, while the cylindrical battery is being repeatedly charged and discharged, as an example, while the cylindrical battery is being charged and discharged beyond the effective use cycle, the circumferential angle |θ A,inner- θ B,inner| may be maintained at an angle of 30 degrees or more and less than 180 degrees.When the positions of the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B are designed, the total rotation amount for the ends (A inner, B inner) of both electrodes can be considered. The total rotation amount may be determined in advance by a charge and discharge cycle test of the cylindrical battery. The total rotation amount may be the cumulative rotation amount when the cylindrical battery is charged and discharged beyond preset effective usage cycles.In a specific example, the circumferential angle |θ A,inner- θ B,inner| 40 degrees or less, 50 degrees or less, 60 degrees or less, 70 degrees or less, 80 degrees or less, 90 degrees or less, 100 degrees or less, 120 degrees or less, 130 degrees or less, 140 degrees or less, 150 degrees or less, 160 degrees or less, 170 degrees or less, or 180 degrees or less.Preferably, the positions of the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR such that the circumferential angle |θ A,inner- θ B,inner| can maintain an angle of 40 degrees or less, 50 degrees or less, 60 degrees or less and 70 degrees or less, 80 degrees or less, 90 degrees or less, 100 degrees or less, 120 degrees or less, 130 degrees or less, 140 degrees or less, 150 degrees or less, 160 degrees or less, 170 degrees or less, or 180 degrees or less while the cylindrical battery is being repeatedly charged and discharged, as an example, while the cylindrical battery is being charged and discharged beyond the effective usage cycles.In a preferred example, the positions of the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR such that the circumferential angle |θ A,inner- θ B,inner| can maintain an angle of, for example, 87 degrees or more and less than 180 degrees while the cylindrical battery is being repeatedly charged and discharged while the cylindrical battery is being charged and discharged beyond the effective use cycles.In another embodiment, the positions of the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR such that |θ A,inner- θ B,inner|, which corresponds to the circumferential angle between the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B, may converge to a specific angle selected in the range of 30 degrees or more and less than 180 degrees while the cylindrical battery is being repeatedly charged and discharged, while charging and discharging the cylindrical battery beyond the effective usage cycles.In a specific example, the positions of the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR such that the circumferential angle |θ A,inner- θ B,inner| is set to the range of 30 degrees to 40 degrees, 40 degrees to 50 degrees, 50 degrees to 60 degrees, 60 degrees to 70 degrees, 70 degrees to 80 degrees, 80 degrees to 90 degrees, 90 degrees to 100 degrees, 100 degrees to 110 degrees, 110 degrees to 120 degrees, 120 degrees to 130 degrees, 130 degrees to 140 degrees, 140 degrees to 150 degrees, 150 degrees to 160 degrees, 160 degrees to 170 degrees, and 170 degrees to less than 180 degrees are converged while the cylindrical battery is being repeatedly charged and discharged, as an example, while the cylindrical battery is being charged and discharged beyond the effective use cycles.In a preferred example, the positions of the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR such that the circumferential angle |θ A,inner- θ B,inner| may converge to the range of 110 degrees to 130 degrees, preferably to the range of 115 degrees to 125 degrees, more preferably to 120 degrees, while the cylindrical battery is being repeatedly charged and discharged, as an example while the cylindrical battery is being charged and discharged beyond the effective use cycles.As described above, the negative electrode A in the winding direction is longer than the positive electrode B, and the positive electrode B is located inside in the winding direction than the negative electrode A. Therefore, the angle (θ A,outer) of the outer circumferential side end (A outer) of the negative electrode A is larger than the angle (θ B,outer) of the outer circumferential side end (B outer) of the positive electrode B.In the embodiment, the circumferential angle |θ A,outer- θ B,outer|, which corresponds to the difference between the angle (θ A,outer) of the outer circumferential side end (A outer) of the negative electrode A and the angle (θ B,outer) of the outer circumferential side end (B outer) of the positive electrode B, may be 10 degrees or more and 90 degrees or less.Preferably, the positions of the outer circumferential side end (A outer) of the negative electrode A and the outer circumferential side end (B outer) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR such that the circumferential angle |θ A,outer- θ B,outer| can maintain an angle of, for example, 10 degrees or more and 90 degrees or less while the cylindrical battery is being repeatedly charged and discharged while the cylindrical battery is being charged and discharged beyond the effective use cycles.When the electrode assembly JR swells to reduce the imbalance of the stress applied to the core C, the circumferential angle |θ A,outer- θ B,outer| may be made to be smaller than the circumferential angle |θ A,inner- θ B,inner|.In specific examples, the circumferential angle |θ A,outer- θ B,outer| may include an angle of 80 degrees to 90 degrees, 70 degrees to 80 degrees, 60 degrees to 70 degrees, 50 degrees to 60 degrees, 40 degrees to 50 degrees, 30 degrees to 40 degrees, 20 degrees to 30 degrees, or 10 degrees to 20 degrees.Preferably, the positions of the outer circumferential side end (A outer) of the negative electrode A and the outer circumferential side end (B outer) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR such that the circumferential angle |θ A,outer- θ B,outer| can maintain an angle of, for example, 80 degrees to 90 degrees, 70 degrees to 80 degrees, 60 degrees to 70 degrees, 50 degrees to 60 degrees, 40 degrees to 50 degrees, 30 degrees to 40 degrees, 20 degrees to 30 degrees, or 10 degrees to 20 degrees while the cylindrical battery is being repeatedly charged and discharged while the cylindrical battery is being charged and discharged beyond the effective usage cycles.In a preferred example, the positions of the outer circumferential side end (A outer) of the negative electrode A and the outer circumferential side end (B outer) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR such that the circumferential angle |θ A,outer- θ B,outer| can maintain an angle of, for example, 10 degrees or more and 32 degrees or less while the cylindrical battery is being repeatedly charged and discharged while the cylindrical battery is being charged and discharged beyond the effective use cycles.In another embodiment, the positions of the outer circumferential side end (A outer) of the negative electrode A and the outer circumferential side end (B outer) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR such that the circumferential angle |θ A,outer- θ B,outer| may converge to a specific angle selected in the range of 10 degrees to 90 degrees while the cylindrical battery is being repeatedly charged and discharged while the cylindrical battery is being charged and discharged beyond the effective use cycles.In a specific example, the positions of the outer circumferential side end (A outer) of the negative electrode A and the outer circumferential side end (B outer) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR such that the circumferential angle |θ A,outer- θ B,outer| may converge to the range of 80 degrees to 90 degrees, 70 degrees to 80 degrees, 60 degrees to 70 degrees, 50 degrees to 60 degrees, 40 degrees to 50 degrees, 30 degrees to 40 degrees, 20 degrees to 30 degrees, or 10 degrees to 20 degrees while the cylindrical battery is repeatedly charged and discharged, as an example, while charging and discharging the cylindrical battery beyond the effective usage cycles.In a more specific example, the positions of the outer circumferential side end (A outer) of the negative electrode A and the outer circumferential side end (B outer) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR such that the circumferential angle |θ A,outer- θ B,outer| may maintain an angle of, for example, 10 degrees to 40 degrees or may converge to a specific angle selected in the range of 10 degrees to 40 degrees while the cylindrical battery is being repeatedly charged and discharged while the cylindrical battery is being charged and discharged beyond the effective use cycles.FIG. 4 is a diagram for illustrating the relative positional relationship between a stress-prone region D 1 and a stress-enhancing region D 2 according to an embodiment of the present disclosure.Referring to FIG. 4, the stress-prone region D 1 surrounded by the first straight line (L B,inner), the second straight line (L A,inner) and the outer periphery of the electrode assembly JR corresponds to the first fan-shaped region and has a circumferential angle (θ 1). In addition, the voltage enhancing region D 2 surrounded by the third straight line (L B,outer), the fourth straight line (L A,outer) and the outer periphery of the electrode assembly JR corresponds to the second fan-shaped region and has a circumferential angle (θ 2).When the line segment dividing the circumferential angle (θ 1) of the stress-prone region D 1 into two equal angles is defined as L a and the diametric line segment perpendicular to the line segment L a and passing through the center of the core C of the electrode assembly JR is defined as O 1 O 2 the cross section of the electrode assembly JR may be classified into a first semicircular region (CL 1) and a second semicircular region (CL 2) facing each other based on the diametric line segment O 1 O 2.As an example, while the cylindrical battery is being charged and discharged repeatedly, while the cylindrical battery is being charged and discharged beyond the effective usage cycles, the voltage enhancing region D 2 hardly rotates, while the voltage susceptible region D 1 may rotate clockwise.As an example, while the cylindrical battery is being repeatedly charged and discharged beyond the effective use cycles, the likelihood of the core C collapsing in the stress-prone region D 1 increases as the stress-enhancing region D 2, specifically, the outer circumferential side end (B outer) of the positive electrode B, becomes closer to the stress-prone region D 1 in the circumferential direction.Therefore, the positions of the core side end (A inner) of the negative electrode A, the core side end (B inner) of the positive electrode B, the outer circumferential side end (A outer) of the negative electrode A, and the outer circumferential side end (B outer) of the positive electrode B can be set in advance at the winding stage of the electrode assembly JR so that the voltage-prone region D 1 is located within the first semicircular region (CL 1) and the voltage-enhancing region D 2 is located within the second semicircular region (CL 2) even when the voltage-prone region D 1 rotates while the cylindrical battery is being repeatedly charged and discharged, as an example, while the cylindrical battery is being charged and discharged beyond the effective usage cycles.According to this construction, the stress applied to the core C in the stress-susceptible region D 1 does not overlap with the stress applied to the core C in the stress-enhancing region D 2 while the cylindrical battery is repeatedly charged and discharged, thereby preventing the stress from rising above a critical level. Here, the critical level may be the stress level that causes the core C to collapse in the stress-prone region D 1.Preferably, regarding the stress distribution, the position of the stress enhancing region D 2 may be designed such that at least a part of the stress applied to the core C in the stress susceptible region D 1 and the stress applied to the core C in the stress enhancing region D 2 face each other.Specifically, the positions of the core-side end (A inner) of the negative electrode A, the core-side end (B inner) of the positive electrode B, the outer circumferential-side end (A outer) of the negative electrode A, and the outer circumferential-side end (B outer) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR such that even when the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B rotate, the voltage enhancing region D 2 is located within the second semicircular region (CL 2), which is defined with respect to the stress-prone region D 1 and at least a part of the stress-enhancing region D 2 overlaps with the third fan-shaped region (R*) which is point-symmetric with the stress-prone region D 1 with respect to the core C while the cylindrical battery is repeatedly charged and discharged, as an example while the cylindrical battery is charged and discharged beyond the effective use cycles.According to another aspect, the positions of the core-side end (A inner) of the negative electrode A, the core-side end (B inner) of the positive electrode B, the outer circumferential-side end (A outer) of the negative electrode A, and the outer circumferential-side end (B outer) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR, so that even when the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B rotate, the voltage enhancing region D 2 is located within the second semicircular region (CL 2), which is defined with respect to the voltage-prone region D 1, and the outer circumferential side end (B outer) of the positive electrode B overlaps with the third fan-shaped region (R*) while the cylindrical battery is being repeatedly charged and discharged, as an example, while the cylindrical battery is being charged and discharged beyond the effective use cycles.According to still another aspect, the positions of the core-side end (A inner) of the negative electrode A, the core-side end (B inner) of the positive electrode B, the outer circumferential-side end (A outer) of the negative electrode A, and the outer circumferential-side end (B outer) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR, so that even when the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B rotate, the voltage enhancing region D 2 is located inside the second semicircular region (CL 2), which is defined with respect to the voltage-susceptible region D 1, and the voltage-enhancing region D 2 overlaps with the fifth straight line (L* a) which divides the circumferential angle of the third fan-shaped region (R*) into two equal angles while the cylindrical battery is repeatedly charged and discharged, as an example while the cylindrical battery is charged and discharged beyond the effective use cycles.According to still another aspect, the positions of the core-side end (A inner) of the negative electrode A, the core-side end (B inner) of the positive electrode B, the outer circumferential-side end (A outer) of the negative electrode A, and the outer circumferential-side end (B outer) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR, so that even when the core-side end (A inner) of the negative electrode A and the core-side end (B inner) of the positive electrode B rotate, the voltage enhancing region D 2 is located inside the second semicircular region (CL 2), which is defined with respect to the voltage-prone region D 1 and the outer circumferential side end (B outer) of the positive electrode B overlaps with the fifth straight line (L* a) which divides the circumferential angle of the third fan-shaped region (R*) into two equal angles while the cylindrical battery is repeatedly charged and discharged, as an example while the cylindrical battery is charged and discharged beyond the effective use cycles.According to the above construction, it is possible to prevent the core C from collapsing or attenuating the phenomenon of collapsing the core C while the cylindrical battery is being repeatedly charged and discharged, as an example, while the cylindrical battery is being charged and discharged beyond the effective use cycles, because the symmetry of the stress applied to the core C is improved because at least a part of the stress applied to the core C in the stress-strengthening region D 2 is opposite to the stress applied to the core C in the stress-prone region D 1.Meanwhile, while the cylindrical battery is being repeatedly charged and discharged, the rotation amount of the voltage susceptible region D 1 is large, and specifically, the rotation amount of the core-side end (A inner) of the negative electrode A is larger than the rotation amount of the core-side end (B inner) of the positive electrode B, and the voltage enhancing region D 2 hardly rotates. In consideration of this difference in the rotation amounts, the collapse of the core can be prevented or reduced by making optimum the positional relationship between the first to fifth straight lines in the circumferential direction of the electrode assembly JR.Specifically, as shown in FIG. 4, the electrode assembly JR may have a winding structure in which the third straight line (LB,outer) and the fourth straight line (LA,outer) are located between the second straight line (LA,inner) and the fifth straight line (L*a) with respect to the circumferential direction on the cross section of the electrode assembly JR.In still another embodiment, the electrode assembly JR may have a winding structure in which the fourth straight line (L A,outer) is located between the fifth straight line (L* a) and the first straight line (L B,inner) and the third straight line (L B,outer) is located between the fourth straight line (L A,outer) and the second straight line (L A,inner) on the cross section of the electrode assembly JR with respect to the circumferential direction.In still another embodiment, the electrode assembly JR may have a winding structure in which the fourth straight line (L A,outer) is located between the fifth straight line (L* a) and the first straight line (L B,inner) and the third straight line (L B,outer) is located between the fifth straight line (L* a) and the second straight line (L A,inner) with respect to the circumferential direction on the cross section of the electrode assembly JR.In still another embodiment, the electrode assembly JR may have a winding structure in which the circumferential angle between the first straight line (L B,inner) and the fourth straight line (L A,outer) is relatively larger than the circumferential angle between the second straight line (L A,inner) and the third straight line (L B,outer) with respect to the circumferential direction on the cross section of the electrode assembly JR.Meanwhile, unlike shown in FIG. 4, the position of the core-side end (A inner) of the negative electrode A and the position of the core-side end (B inner) of the positive electrode B may be switched.In this case, the electrode assembly JR may have a winding structure in which the third straight line (L B,outer) and the fourth straight line (L A,outer) are located between the first straight line (L B,inner) and the fifth straight line (L* a) on the cross section of the electrode assembly JR with respect to the circumferential direction.In still another embodiment, the electrode assembly JR may have a winding structure in which the fourth straight line (L A,outer) is located between the fifth straight line (L* a) and the second straight line (L A,inner) and the third straight line (L B,outer) is located between the fourth straight line (L A,outer) and the first straight line (L B,inner) on the cross section of the electrode assembly JR with respect to the circumferential direction.In still another embodiment, the electrode assembly JR may have a winding structure in which the fourth straight line (L A,outer) is located between the fifth straight line (L* a) and the second straight line (L A,inner) and the third straight line (L B,outer) is located between the fifth straight line (L* a) and the first straight line (L B,inner) with respect to the circumferential direction on the cross section of the electrode assembly JR.In still another embodiment, the electrode assembly JR may have a winding structure in which the circumferential angle between the second straight line (L A,inner) and the fourth straight line (L A,outer) is relatively larger than the circumferential angle between the first straight line (L B,inner) and the third straight line (L B,outer) with respect to the circumferential direction on the cross section of the electrode assembly JR.Preferably, the winding structures of the electrode assembly JR described above may be maintained while the cylindrical battery is being repeatedly charged and discharged, for example, while the cylindrical battery is being charged and discharged beyond the effective usage cycles. To satisfy this condition, the positions of the core side end (A inner) of the negative electrode A, the core side end (B inner) of the positive electrode B, the outer circumferential side end (A outer) of the negative electrode A, and the outer circumferential side end (B outer) of the positive electrode B may be set in advance at the winding stage of the electrode assembly JR.According to still another aspect of the present disclosure, depending on the relative positions of the core-side end (A inner) of the negative electrode A, the core-side end (B inner) of the positive electrode B, the outer circumferential-side end (A outer) of the negative electrode A, and the outer circumferential-side end (B outer) of the positive electrode B, the speed at which a portion of the outer circumference of the electrode assembly corresponding to the outer circumferential-side end (B outer) of the positive electrode B contacts the inner circumference of the battery case may vary.FIGS. 5 ato 5 care sectional views of cylindrical batteries showing three different embodiments for the relative positions of a core-side end (A inner) and an outer circumferential-side end (A outer) of the negative electrode, and a core-side end (B inner) and an outer circumferential-side end (B outer) of the positive electrode B.The electrode assembly JR shown in FIGS. 5 ato 5 c has specifications that can be used in a cylindrical battery with a form factor of 4680 (diameter: 46 mm, height: 80 mm).When the cylindrical battery in FIG. 5 ais in the BOL state, the core-side end (Ainner) of the negative electrode A and the outer circumferential-side end (Bouter) of the positive electrode B are located on the same line in the radial direction of the electrode assembly JR.When the cylindrical battery in FIG. 5 bis in the BOL state, the core side end (B inner) of the positive electrode B and the outer circuit side end (B outer) of the positive electrode B are located on the same line in the radial direction of the electrode assembly JR.When the cylindrical battery in FIG. 5 cis in the BOL state, the voltage boost region D 2 is located within the second semicircular region (CL 2), which is defined with respect to the voltage prone region D 1, and is located so as to overlap approximately the center of the fan-shaped region (R*), which is point-symmetric with the voltage prone region D 1.When the cylindrical battery of FIG. 5 aand the cylindrical battery of FIG. 5 bare repeatedly charged and discharged, the outer peripheral side end (B outer) of the positive electrode B starts to contact the inner surface of the battery case H at the point where the volume of the negative electrode A increases by about 2.5%.Meanwhile, when the cylindrical battery of FIG. 5 cis repeatedly charged and discharged, the outer peripheral side end (B outer) of the positive electrode B starts to contact the inner surface of the battery case H at the point where the volume of the negative electrode A increases by about 5%.As the cylindrical battery in FIG. 5 c, when the point at which the outer circumferential side end (B outer) of the positive electrode B contacts the inner surface of the battery case H is decelerated, it means that circularity of the cross section of the electrode assembly JR is relatively well maintained.As with the cylindrical battery in FIG. 5 c, if the circularity of the cross section of the electrode assembly is relatively well maintained, the possibility of the core collapsing can be reduced as compared with the cylindrical battery in FIGS. 5 aand 5 b, even if the charge and discharge cycle is increased.FIGS. 6 aand 6 bare diagrams showing the tendency of the core to collapse according to the diameter of the recess present in the core of the electrode assembly JR.Referring to FIGS. 6 aand 6 b, when the diameter of the core C is changed to 6 mm, 7 mm, and 8 mm, the possibility of collapsing the core increases as the diameter of the core C is larger. This is because the smaller the radius of curvature, the greater the resistance to stress.Preferably, the core diameter of the electrode assembly JR may be set to 7 mm or less, 6.5 mm or less, and preferably 6 mm or less. The core diameter of the electrode assembly JR may be set to 3 mm or more, taking into account the size of the core member used in the winding process and the welding process using the recess of the core.Next, the effect of the relative arrangement of the stress-prone portion D 1 and the stress-strengthening portion D 2 in the circumferential direction of the electrode assembly on the circularity of the electrode assembly core by a cycle test will be explained.In the electrode assemblies manufactured as samples, the positions of the core-side end (A inner) of the negative electrode A, the core-side end (B inner) of the positive electrode B, the outer circumferential-side end (A outer) of the negative electrode A, and the outer circumferential-side end (B outer) of the positive electrode B are set with different conditions along the circumferential direction. The positioning design applied to each sample will be explained in detail using the CT cross-sectional photograph of the cylindrical sample battery.First, the manufacturing method of the electrode assembly, the manufacturing method of the cylindrical battery, the initial activation conditions, and the charge and discharge conditions in the use cycle after the initial activation, which are usually applied to the samples, will be explained.< Of Sample Electrode Array>First, a positive electrode and a negative electrode were prepared. The positive electrode has a structure in which a positive electrode active material is coated on both sides of an aluminum foil along the longitudinal direction (winding direction). The negative electrode has a structure in which a negative electrode active material is coated on both sides of a copper foil along the longitudinal direction (winding direction). The positive and negative electrodes have an uncoated portion along the long side end that is not coated with active material. The length, width, and thickness of the aluminum foil are 4015 mm, 65 mm, and 15 m, respectively. The length, width, and thickness of the copper foil are 4103 mm, 70 mm, and 10 m, respectively. The coating width and coating length of the positive electrode active material are 65 mm and 4015 mm, respectively. The coating width and coating length of the negative electrode active material are 70 mm and 4103 mm, respectively. As the positive electrode active material, aluminum-doped lithium nickel manganese cobalt oxide was used. As the negative electrode active material, a mixed negative electrode material containing natural graphite and artificial graphite mixed in a weight ratio of 50:50 was used. The thickness of the positive electrode was set to 161 m including the thickness of the active material coating layer and the aluminum foil, and the thickness of the negative electrode was set to 189 m including the thickness of the active material coating layer and the copper foil. As the separator, a film having an inorganic particle coating layer formed on both sides of a porous polyethylene substrate was used, and the length, width, and thickness of the separator were 4235 mm, 72 mm, and 13 m, respectively. One separator was disposed between the positive electrode and the negative electrode, and the other separator was used as a winding film. The sample electrode assembly was manufactured using a known jelly roll winding process. In the sample electrode assembly, the winding turn of the positive electrode and the negative electrode is about 50 turns. The core, diameter and height of the sample electrode assembly are 6 mm, 44.86 mm and 73.3 mm, respectively.< Of Cylindrical Sample Battery>The cylindrical sample battery was manufactured to have a cross-sectional structure shown in FIG. 32, which will be explained later. The outer diameter, thickness and inner diameter of the battery case are 46 mm, 0.45 mm and 45.1 mm, respectively. A nonaqueous electrolyte in which 1.25 mol of lithium salt LiPF6was added to a solvent having EC / EMC / DMC mixed in a volume ratio of 20 / 5 / 75 was injected into the cylindrical sample battery. The cylindrical sample battery has a capacity of 12.5 Ah and an operating voltage of 2.5 V to 4.2 V. The upper limit voltage is the full charge voltage and corresponds to the SOC (State of Charge) of 100%. The lower limit voltage is the full discharge voltage and corresponds to the SOC of 0%.< Of Cycle Initial State>After the electrolyte injection, an activation process was performed to activate the cylindrical sample battery. After the activation, the SOC of the cylindrical sample battery is 30%. The state of the cylindrical battery which is fully discharged after the active charging is considered as a beginning of life (BOL) state. During the active charging of the cylindrical battery, the magnitude of the charging current and the temperature were set to 1 / 4 c and 20° C, respectively. Here, c is a symbol representing the c rate of the current, and the same applies below. During the full discharge of the cylindrical sample battery, the magnitude of the discharge current and the temperature were set to (1 / 3 c) and 20° C., respectively.<CT Cross-sectional Photograph, Measurement of Electrode End Rotation Angle and Circularity of Core of Electrode Assembly in BOL State>A CT cross-sectional photograph was obtained by performing CT tomography on the cylindrical sample battery in the BOL state using Tomex m300 devices from General Electric. Then, the positions of the core side end (A inner) of the negative electrode A, the core side end (B inner) of the positive electrode B, the outer circumferential side end (A outer) of the negative electrode A, and the outer circumferential side end (B outer) of the positive electrode B were identified on the CT cross-sectional photograph. In addition, the angle of the voltage-prone portion D 1 and the voltage-boosting portion D 2 along the circumferential direction with respect to the core center of the electrode assembly and the amount of rotation of the negative electrode end and the positive electrode end on the core and the outer periphery of the electrode assembly were measured. In addition, when the distance from the core center to the electrode winding turn located on the innermost side on the CT cross-sectional photograph was measured at equal intervals 24 times along the circumferential direction, the ratio (%) of the minimum value to the maximum value of the distance was calculated as the circularity value of the electrode array core. Circularity of the electrode array core is a measure for evaluating symmetry. As circularity decreases, the shape of the core cannot maintain its original shape and has a distorted shape. If circularity is decreased beyond a threshold level, the core cannot maintain its shape but collapse as shown in FIG. 2c.< Of Charge and Discharge Cycle>The cylindrical sample battery in the BOL state was mounted on a cycler, and the cycle test was continuously repeated 300 times or more. 300 or more cycles may be an example of the effective usage cycles. Cycle tests performed per day were limited to three. One cycle includes a full charge process and a full discharge process. There was a rest time for one hour between the full charge process and the full discharge process. The cycle test temperature was set at 20° C. During full charge, the magnitude of the charging current was set to 1 / 4 c and charging was performed for 4 hours, and during full discharge, the magnitude of the discharging current was set to 1 / 3 c and discharging was performed for 3 hours. During full charge, the voltage of the cylindrical sample battery increases from 2.5 V to 4.2 V, and during full discharge, the voltage of the cylindrical sample battery decreases from 4.2 V to 2.5 V.<CT Cross-sectional Photograph, Measurement of Electrode End Rotation Angle and Circularity of Core of Electrode Assembly after Cycle Tests Are Performed.A CT cross-sectional photograph was obtained by performing CT tomography using the above-described apparatuses on a cylindrical sample battery subjected to a predetermined number of cycle tests. Then, the positions of the core side end (A inner) of the negative electrode A, the core side end (B inner) of the positive electrode B, the outer circumferential side end (A outer) of the negative electrode A, and the outer circumferential side end (B outer) of the positive electrode B were identified on the CT cross-sectional photograph. In addition, the angle of the voltage prone portion D 1 and the voltage boosting portion D 2 with respect to the core center of the electrode assembly and the amount of rotation of the negative electrode end and the positive electrode end on the core and the outer periphery of the electrode assembly were measured. In addition, when the distance from the core center to the electrode winding turn located on the innermost side on the CT cross-sectional photograph was measured at equal intervals 24 times along the circumferential direction, the ratio (%) of the minimum value to the maximum value of the distance was calculated as the circularity of the electrode array core.<Cycle Test for Cylindrical #1 Sample Battery>FIG. 7 ais a CT cross-sectional photograph taken when a cylindrical battery prepared as #1 sample (hereinafter, #1 sample battery) is in the BOL state (start of life). FIG. 7 bis a CT cross-sectional photograph taken after 200 cycle tests were performed on the #1 sample battery. FIG. 7 cis a CT cross-sectional photograph taken after 300 cycle tests were performed on the #1 sample battery.Referring to FIGS. 7 ato 7 c, in the CT cross-sectional photograph, the positive electrode and the negative electrode are wound clockwise, and the negative electrode is wound in front of the positive electrode. Therefore, the negative electrode is placed centripetally with respect to the center of the core of the electrode assembly than the positive electrode. The winding direction of the positive electrode and the negative electrode depends on the standing direction of the cylindrical battery when a CT cross-sectional photograph is taken. When the standing direction of the cylindrical battery is reversed, the winding direction of the electrode shown on the CT cross-sectional photograph may appear reversed.When the #1 sample battery was in the BOL state, the angle for the voltage-prone region D 1 between the negative electrode core-side end (A inner) and the positive electrode core-side end (B inner) was measured to 160.89 degrees, and the angle for the voltage-boosted region D 2 between the negative electrode outer-circumferential-side end (A outer) and the positive electrode outer-circumferential-side end (B outer) was measured to 31.71 degrees. In addition, circularity of the electrode array core was calculated to be 89.9%.For the #1 sample battery, when 200 cycle tests were performed, the angle for the voltage susceptible region D 1 between the negative electrode core side end (A inner) and the positive electrode core side end (B inner) was measured to 175.55 degrees, and the angle for the voltage enhancing region D 2 between the negative electrode outer circumferential side end (A outer) and the positive electrode outer circumferential side end (B outer) was measured to 30.58 degrees.The negative electrode core side end (A inner) and the positive electrode core side end (B inner) were rotated counterclockwise as compared with the BOL state. The rotation amount of the negative electrode core side end (A inner) was relatively larger than the rotation amount of the positive electrode core side end (B inner), and as a result, the angle of the stress-prone portion D 1 was increased by 14.66 degrees compared to the BOL state.The negative electrode outer circumferential side end (A outer) and the positive electrode outer circumferential side end (B outer) hardly rotate compared to the BOL state. In measurements, the angle of the voltage boost region D 2 was decreased by 1.13 degrees compared to the BOL state. Since the operator's manual error is involved in measuring the angle, the reduction of the angle of the voltage boosting region D 2 is not reasonable.Meanwhile, when the CT cross-sectional photograph is classified into the first semicircular region (CL 1) and the second semicircular region (CL 2) based on the diametric line segment (O 1 O 2) passing through the center of the electrode array core and being perpendicular to the straight line dividing the circumferential angle of the stress-prone region D 1 into two equal angles, the positions of the stress-prone region D 1 and the stress-boosting region D 2 are continuously held within the first semicircular region (CL 1) and the second semicircular region (CL 2) respectively, while 200 cycles of charging and discharging are performed.In addition, the voltage enhancing region D 2 maintains its position within the second semicircular region (CL 2), which is defined based on the voltage susceptible region D 1, during 200 cycles of charging and discharging, and is continuously maintained in an overlapping state with the two-division line segment (L*a) of the fan-shaped region (R*) which is point-symmetric with the voltage susceptible region D 1 with respect to the center of the core.After 200 cycles of charging and discharging, circularity of the electrode array core was calculated to be 89.7%, which was decreased by 0.2% as compared with circularity of 89.9% in the BOL state, and there was substantially no change.For the #1 sample battery, when 300 cycle tests were performed, the angle for the voltage susceptible region D 1 between the negative electrode core side end (Ainner) and the positive electrode core side end (Binner) was measured to 178.49 degrees, and the angle for the voltage enhancing region D 2 between the negative electrode outer circumferential side end (Aouter) and the positive electrode outer circumferential side end (Bouter) was measured to 30.77 degrees.The negative electrode core side end (Ainner) and the positive electrode core side end (Binner) were further rotated counterclockwise as compared with the state after 200 cycles. Since the amount of rotation of the negative electrode core side end (Ainner) is relatively larger than the amount of rotation of the positive electrode core side end (Binner), the angle of the stress-prone region D 1 was increased by 2.94 degrees compared to the state after 200 cycles.There is no substantial change in the negative electrode outer circumferential side end (A outer) and the positive electrode outer circumferential side end (B outer) compared to the state after 200 cycles. This is because, as the number of cycles increases to some extent, the outer peripheral surface of the electrode assembly where the positive electrode outer peripheral side end (B outer) is located comes strongly into close contact with the inner surface of the battery case, thereby producing an anchoring effect that fixes its position. Therefore, the angle of the voltage boosting region D 2 shows substantially no change compared with the state after 200 cycles.The stress-prone portion D 1 and the stress-enhancing portion D 2 maintain their positions within the first semicircular portion (CL 1) and the second semicircular portion (CL 2) respectively, even during 300 cycles of charging and discharging. In addition, the voltage enhancing region D2 maintains its position within the second semicircular region (CL 2), which is defined with respect to the voltage susceptible region D1, during 300 cycles of charging and discharging, and is continuously maintained in an overlapping state with the two-division line segment (L* a) of the fan-shaped region (R*) which is point-symmetrical with the voltage susceptible region D1 with respect to the center of the core.After 300 cycles of charging and discharging, circularity of the electrode array core was calculated to be 89.7%, and there was no change compared with circularity of 89.7% after 200 cycles.There is substantially no change between the calculated circularity in the BOL state, after 200 cycles, and after 300 cycles. In addition, the relative positional relationship between the above-described first to fifth straight lines remained identical while the cycle test was repeated. The arrangement configuration of the voltage prone portion D 1 and the voltage boost portion D 2 applied to the #1 sample battery maintains the circularity of the electrode arrangement core and distributes the voltage well, which is effective in preventing or mitigating the collapse of the core in the effective use cycles of 200 cycles or more or 300 cycles or more.<Cycle Test for Cylindrical #2 Sample Battery>FIG. 8 ais a CT cross-sectional photograph taken when a cylindrical battery prepared as #2 sample (hereinafter, #2 sample battery) is in the BOL state. FIG. 8 bis a CT cross-sectional photograph taken after 900 cycle tests, which are significantly larger than in the first embodiment, have been performed on the #2 sample battery.Referring to FIGS. 8 ato 8 c, in the CT cross-sectional photograph, the positive electrode and the negative electrode are wound clockwise, and the negative electrode is wound in front of the positive electrode. Therefore, the negative electrode is placed centripetally with respect to the center of the core of the electrode assembly than the positive electrode.When the #2 sample battery was in the BOL state, the angle for the voltage-prone region D1 between the negative electrode core-side end (A inner) and the positive electrode core-side end (B inner) was measured to 109.95 degrees, and the angle for the voltage-boosted region D2 between the negative electrode outer-circumferential-side end (A outer) and the positive electrode outer-circumferential-side end (B outer) was measured to 14.56 degrees. In addition, circularity of the electrode array core was calculated to be 93.04%.For the #2 sample battery, when 900 cycle tests were continuously performed, the angle for the voltage-prone region D 1 between the negative electrode core-side end (A inner) and the positive electrode core-side end (B inner) was measured to 133.31 degrees, and the angle for the voltage-boosted region D 2 between the negative electrode outer-circumferential-side end (A outer) and the positive electrode outer-circumferential-side end (B outer) was measured to 13.47 degrees.The negative electrode core side end (A inner) and the positive electrode core side end (B inner) were rotated significantly counterclockwise compared to the BOL state. The rotation amount of the negative electrode core side end (A inner) was relatively larger than the rotation amount of the positive electrode core side end (B inner), and as a result, the angle of the stress-prone portion D 1 was increased by 23.36 degrees compared to the BOL state.The negative electrode outer circumferential side end (A outer) and the positive electrode outer circumferential side end (B outer) hardly rotate compared to the BOL state. In measurements, the angle of the voltage boost region D 2 was slightly decreased compared to the BOL state. Since the operator's manual error is involved in measuring the angle, the reduction of the angle of the voltage boosting region D 2 is not reasonable.Meanwhile, the CT cross-sectional photograph may be classified into the first semicircular region (CL 1) and the second semicircular region (CL 2) based on the diametrical line segment (O 1 O 2) passing through the center of the electrode array core and being perpendicular to the straight line dividing the circumferential angle of the stress-prone region D 1 into two equal angles.The position of the stress-prone portion D 1 was continuously held within the first semicircular portion (CL 1) while 900 cycles of charging and discharging were performed.The tension enhancing region D2 is in the second semicircular region (CL 2), at the beginning of the cycle test, but moves to the first semicircular region (CL 1), while going to the middle of the cycle test, while the tension susceptible region D1 rotates counterclockwise. In addition, the stress enhancing region D 2 began to overlap with the stress susceptible region D 1 in the latter half of the cycle test, and after 900 cycles, the position of the outer circumferential side positive electrode end (B outer) of the stress enhancing region D 2 becomes substantially the same as the position of the core side negative electrode end (A inner) of the negative electrode. As the number of cycles increases, the negative electrode core-side end (Ainner) rotates counterclockwise, so that the circumferential angle between the negative electrode core-side end (Ainner) and the positive electrode outer circumferential-side end (Bouter) gradually decreases. Therefore, before 900 cycles, the positive electrode outer circumferential side end (B outer) is spaced counterclockwise from the stress-prone region D 1 along the circumferential direction, and if the cycle test is repeated beyond 900 cycles, the positive electrode outer circumferential side end (B outer) would be located within the stress-prone region D 1, so that the stress-enhancing region D 2 is expected to completely overlap with the stress-prone region D 1.After 900 cycles of charging and discharging, circularity of the electrode array core was calculated to be 92.10%, which was reduced by 0.94% as compared with circularity of 93.04% in the BOL state. This reduction in circularity is not a reasonable reduction when it is considered that the number of cycles is 900.The experimental results for the #2 sample battery support that the relative positions of the voltage prone region D 1 and the voltage boost region D 2 in the circumferential direction are effective in maintaining circularity of the electrode array core when designed intentionally according to an embodiment of the present disclosure.In other words, when the position of the electrode end is designed from the beginning in consideration of the rotation amount of the electrode end according to the increase of the cycles so that the circumferential position of the voltage enhancing region D 2, particularly the outer circumferential side end (B outer) of the positive electrode, does not overlap with the inner region of the voltage prone region D 1 during 900 cycles, the circularity of the electrode array core can be maintained without significant change even when the charge and discharge cycle is repeated 900 times or more. As a result, the collapsing of the electrode array core can be prevented or reduced.FIG. 9 is a graph showing the results of measuring the rotation amount of the negative electrode core side end (A inner) and the positive electrode core side end (B inner) while repeating the cycle test for the #2 sample battery immediately after the production.Referring to FIG. 9, the rotation amount of the negative electrode core side end (A inner) and the positive electrode core side end (B inner) in the #2 sample battery shows a pattern that gradually increases as the number of cycles increases. The rotation amount of the negative electrode core side end (A inner) and the positive electrode core side end (B inner) is the largest in the activation cycle portion. The rotation amount of the negative electrode core side end (A inner) and the positive electrode core side end (B inner) shows a linear increase pattern in the cycle repeating section after the activation cycle. In the #2 sample battery, after 900 cycles, the rotation amounts of the negative electrode core side end (A inner) and the positive electrode core side end (B inner) were measured to 77.9 degrees and 40 degrees, respectively. Meanwhile, referring to the partially enlarged view of the local area of the graph, when a cycle test is performed, the rotation amount of the negative electrode core-side end (A inner) gradually increases while showing a pattern that increases during the full charge process and then decreases again during the full discharge process. Conversely, the rotation amount of the positive electrode core side end (B inner) gradually increases while showing a pattern that decreases during the full charge process and then increases during the full discharge process.The test results of the #2 sample battery support that the change in circularity is not significant even when 900 or more cycle tests are performed on the #1 sample battery. When the #2 sample battery is in the BOL state, the voltage prone area D 1 and the voltage boosting area D 2 are spaced apart by about 63.34 degrees in the circumferential direction, but in the #1 sample battery, the voltage prone area D 1 and the voltage boosting area D 2 are spaced apart by 71.71 degrees in the circumferential direction, which is larger than 63.34 degrees, even after 300 cycles. Therefore, even when charging and discharging tests are additionally performed on the #1 sample battery from 300 cycles to 900 cycles, the positive electrode outer circumferential side end (B outer) does not overlap with the inner region of the voltage susceptible region D 1 due to the linear increase in electrode rotation. Therefore, similar to the test results of the #2 sample battery, it is apparent to those skilled in the art that at least the circularity of the electrode array core in the #1 sample battery is not reduced to the extent that the core is caused to collapse.<Cycle Test for Cylindrical #3 Sample Battery>FIG. 10 ais a CT cross-sectional photograph taken when a cylindrical battery prepared as #3 sample (hereinafter, #3 sample battery) is in the BOL state. FIG. 10 bis a CT cross-sectional photograph taken after 900 cycle tests were performed on the #3 sample battery.Referring to FIGS. 10 aand 10 b, in the CT cross-sectional photograph, the positive electrode and the negative electrode are wound clockwise, and the negative electrode is wound in front of the positive electrode. Therefore, the negative electrode is placed centripetally with respect to the center of the core of the electrode assembly than the positive electrode.When the #3 sample battery was in the BOL state, the angle for the voltage-prone region D1 between the negative electrode core-side end (A inner) and the positive electrode core-side end (B inner) was measured to be 90.67 degrees, and the angle for the voltage-boosted region D2 between the negative electrode outer-circumferential-side end (A outer) and the positive electrode outer-circumferential-side end (B outer) was measured to be 16.59 degrees. In addition, circularity of the electrode array core was calculated to be 93.23%.For the #3 sample battery, when 900 cycle tests were continuously performed, the angle for the voltage susceptible region D1 between the negative electrode core-side end (A inner) and the positive electrode core-side end (B inner) was measured to be 110.52 degrees, and the angle for the voltage enhancing region D2 between the negative electrode outer circumferential side end (A outer) and the positive electrode outer circumferential side end (B outer) was measured to be 16.14 degrees.The negative electrode core side end (A inner) and the positive electrode core side end (B inner) were rotated significantly counterclockwise compared to the BOL state. The rotation amount of the negative electrode core side end (A inner) was relatively larger than the rotation amount of the positive electrode core side end (B inner), and as a result, the angle of the stress-prone portion D 1 was increased by 19.85 degrees compared to the BOL state.The negative electrode outer circumferential side end (A outer) and the positive electrode outer circumferential side end (B outer) hardly rotate compared to the BOL state. In measurements, the angle of the voltage boost region D 2 was slightly decreased compared to the BOL state. Since the operator's manual error is involved in measuring the angle, the reduction of the angle of the voltage boosting region D 2 is not reasonable.Meanwhile, the CT cross-sectional photograph may be classified into the first semicircular region (CL 1) and the second semicircular region (CL 2) based on the diametrical line segment (O 1 O 2) passing through the center of the electrode array core and being perpendicular to the straight line dividing the circumferential angle of the stress-prone region D 1 into two equal angles.The position of the stress-prone portion D 1 was continuously held within the first semicircular portion (CL 1) while 900 cycles of charging and discharging were performed.The voltage enhancing region D 2 overlaps with the voltage-prone region D 1 from the BOL state, and even after 900 cycles, a part of the voltage enhancing region D 2, specifically, the circumferential position of the positive electrode outer-circumferential-side end (B outer), overlaps with the voltage-prone region D 1. The arrangement configuration of the voltage-prone portion D 1 and the voltage-boosting portion D 2 applied to the #3 sample battery does not correspond to the embodiment of the present disclosure.After 900 cycles of charging and discharging, circularity of the electrode array core was calculated to be 89.65%, which was decreased by about 3.58% as compared with circularity of 93.23% in the BOL state. This decrease in circularity is a reasonable decrease as compared with the #1 sample battery and the #2 sample battery. Therefore, the electrode coil rotates in the 3 o'clock to 6 o'clock direction on the CT cross-sectional photograph obtained after 900 cycles are deformed to the extent that its curvature can be recognized with the naked eye. Therefore, when the #3 sample battery is additionally charged and discharged over 900 times, there is a high possibility of the core collapsing.The experimental results for the #3 sample battery support that when the positions of the voltage prone portion D 1 and the voltage boosting portion D 2 in the circumferential direction are not intentionally designed according to the embodiments of the present disclosure, the circularity of the electrode array core cannot be maintained.In other words, when the position of the electrode is not designed from the beginning in consideration of the linear increase in the rotation amount of the positive and negative electrode core side ends, so that the circumferential position of the voltage enhancing region D 2, particularly the outer circumferential side end (Bouter) of the positive electrode, is not included in the voltage prone region D 1 during 900 cycles, the circularity of the electrode array core cannot be maintained when the charge and discharge cycle is repeated 900 times or more. As a result, the collapsing of the electrode assembly core cannot be prevented or reduced while the cylindrical battery is being charged and discharged beyond the effective use cycles.<Cycle Test for Cylindrical #4 Sample Battery>FIG. 11 ais a CT cross-sectional photograph taken when a cylindrical battery prepared as #4 sample (hereinafter, #4 sample battery) is in the BOL state. FIG. 11 bis a CT cross-sectional photograph taken after 700 cycle tests were performed on the #4 sample battery.Referring to FIGS. 11 aand 11 b, in the CT cross-sectional photograph, the positive electrode and the negative electrode are wound clockwise, and the negative electrode is wound in front of the positive electrode. Therefore, the negative electrode is placed centripetally with respect to the center of the core of the electrode assembly than the positive electrode.When the #4 sample battery was in the BOL state, the angle for the voltage-prone region D1 between the negative electrode core-side end (A inner) and the positive electrode core-side end (B inner) was measured to 87.43 degrees, and the angle for the voltage-boosted region D2 between the negative electrode outer-circumferential-side end (A outer) and the positive electrode outer-circumferential-side end (B outer) was measured to 19.5 degrees. In addition, circularity of the electrode array core was calculated to be 95.24%.For the #4 sample battery, when 700 cycle tests were continuously performed, the angle for the voltage susceptible region D1 between the negative electrode core side end (A inner) and the positive electrode core side end (B inner) was measured to be 101.81 degrees, and the angle for the voltage enhancing region D2 between the negative electrode outer circumferential side end (A outer) and the positive electrode outer circumferential side end (B outer) was measured to be 16.2 degrees.The negative electrode core side end (A inner) and the positive electrode core side end (B inner) were rotated significantly counterclockwise compared to the BOL state. The rotation amount of the negative electrode core side end (A inner) was relatively larger than the rotation amount of the positive electrode core side end (B inner), and as a result, the angle of the stress-prone portion D 1 was increased by 14.38 degrees compared to the BOL state.The negative electrode outer circumferential side end (A outer) and the positive electrode outer circumferential side end (B outer) hardly rotate compared to the BOL state. In measurements, the angle of the voltage boost region D 2 was reduced by 3.3 degrees compared to the BOL state.Meanwhile, the CT cross-sectional photograph may be classified into the first semicircular region (CL 1) and the second semicircular region (CL 2) based on the diametrical line segment (O 1 O 2) passing through the center of the electrode array core and being perpendicular to the straight line dividing the circumferential angle of the stress-prone region D 1 into two equal angles.The position of the stress-prone portion D 1 was continuously held within the first semicircular portion (CL 1) while 700 cycles of charging and discharging were performed.The stress enhancing region D 2 overlaps with the stress susceptible region D 1 from the BOL state, but after 700 cycles, the stress enhancing region D 2 does not overlap with the stress susceptible region D 1 and is located in the second semicircular region (CL 2). The stress enhancing region D 2 initially maintains an overlapped state with the stress susceptible region D 1 in the circumferential direction during the 700 cycle tests. The stress enhancing region D 2 is spaced from the stress susceptible region D 1 in the circumferential direction from the center of the cycle test, and enters the second semicircular region (CL 2) in the second half. The arrangement of the voltage-prone portion D 1 and the voltage-boosting portion D 2 applied to the #4 sample battery does not correspond to the embodiment of the present disclosure. This is because a voltage is concentrated in the core of the electrode assembly because the voltage-prone region D 1 and the voltage-boosting region D 2 overlap while a significant number of cycles are performed from the BOL state.After 700 cycles of charging and discharging, circularity of the electrode array core was calculated to be 87.86%, which was decreased by about 7.38% as compared with circularity of 95.24% in the BOL state. This decrease in circularity is a reasonable decrease as compared with the #1 sample battery and the #2 sample battery. Therefore, the electrode coil rotates in the 9 o'clock to 1 o'clock direction on the CT cross-sectional photograph obtained after 700 cycles are deformed to the extent that its curvature can be recognized with the naked eye. Therefore, when the #4 sample battery is additionally charged and discharged beyond 700 times, there is a high possibility of the core collapsing.The cycle test results for the #4 sample battery support that when the positions of the voltage prone portion D 1 and the voltage boosting portion D 2 in the circumferential direction are not intentionally designed according to the embodiments of the present disclosure, the circularity of the electrode array core cannot be maintained.In other words, when the position of the electrode within the electrode assembly is not designed from the beginning in consideration of the linear increase in the rotation amount of the positive and negative electrode core side ends, so that the circumferential position of the voltage enhancing region D 2, particularly the outer circumferential side end (B outer) of the positive electrode, is not included in the voltage prone region D 1 during 700 cycles, the circularity of the electrode assembly core cannot be maintained when the charge and discharge cycle is repeated 700 times or more. As a result, the collapsing of the electrode assembly core cannot be prevented or reduced while the cylindrical battery is being charged and discharged beyond the effective use cycles.<Cycle Test for Cylindrical #5 Sample Battery>FIG. 12 ais a CT cross-sectional photograph taken when a cylindrical battery prepared as #5 sample (below #5 sample battery) is in the BOL state. FIG. 12 bis a CT cross-sectional photograph taken after 420 cycle tests were performed on the #5 sample battery.Referring to FIGS. 12 aand 12 b, in the CT cross-sectional photograph, the positive electrode and the negative electrode are wound clockwise, and the negative electrode is wound in front of the positive electrode. Therefore, the negative electrode is placed centripetally with respect to the center of the core of the electrode assembly than the positive electrode.When the #5 sample battery was in the BOL state, the angle for the voltage-prone region D1 between the negative electrode core-side end (A inner) and the positive electrode core-side end (B inner) was measured to be 104.79 degrees, and the angle for the voltage-boosted region D2 between the negative electrode outer-circumferential-side end (A outer) and the positive electrode outer-circumferential-side end (B outer) was measured to be 17.9 degrees. In addition, circularity of the electrode array core was calculated to be 92.65%.For the #5 sample battery, when 420 cycle tests were continuously performed, the angle for the voltage susceptible area D1 between the negative electrode core-side end (A inner) and the positive electrode core-side end (B inner) was measured to 129.38 degrees, and the angle for the voltage enhancing area D2 between the negative electrode outer circumferential side end (A outer) and the positive electrode outer circumferential side end (B outer) was measured to 15.72 degrees.The negative electrode core side end (A inner) and the positive electrode core side end (B inner) were rotated significantly counterclockwise compared to the BOL state. The rotation amount of the negative electrode core side end (A inner) was relatively larger than the rotation amount of the positive electrode core side end (B inner), and as a result, the angle of the stress-prone portion D 1 was increased by 24.59 degrees compared to the BOL state.The negative electrode outer circumferential side end (A outer) and the positive electrode outer circumferential side end (B outer) hardly rotate compared to the BOL state. In measurements, the angle of the voltage boost region D 2 was decreased by 2.18 degrees compared to the BOL state.Meanwhile, the CT cross-sectional photograph may be classified into the first semicircular region (CL 1) and the second semicircular region (CL 2) based on the diametrical line segment (O 1 O 2) passing through the center of the electrode array core and being perpendicular to the straight line dividing the circumferential angle of the stress-prone region D 1 into two equal angles.The position of the stress-prone portion D 1 was continuously held within the first semicircular portion (CL 1) while 420 cycles of charging and discharging were performed.The stress enhancing region D 2 starts to overlap with the stress susceptible region D 1 from the middle of the cycle test, and completely overlaps with the stress susceptible region D 1 after 420 cycles. The arrangement of the voltage-prone region D 1 and the voltage-boosting region D 2 applied to the #5 sample battery does not correspond to the embodiment of the present disclosure. This is because a voltage is concentrated in the core of the electrode assembly because the voltage-prone region D 1 and the voltage-boosting region D 2 overlap from the middle of the cycle test to the later part of the cycle test.After 420 cycles of charging and discharging, circularity of the electrode array core was calculated to be 90.63%, which was decreased by about 2.02% as compared with circularity of 92.65% in the BOL state. This decrease in circularity is a reasonable decrease as compared with the #1 sample battery and the #2 sample battery. Therefore, the electrode coil rotates in the 3 o'clock to 7 o'clock direction on the CT cross-sectional photograph obtained after 420 cycles are deformed to the extent that its curvature can be recognized with the naked eye. Therefore, when the #5 sample battery is additionally charged and discharged over 420 times, there is a high possibility of core collapse.The cycle test results for the #5 sample battery support that if the positions of the voltage prone region D 1 and the voltage boosting region D 2 in the circumferential direction are not intentionally designed according to the embodiments of the present disclosure, the circularity of the electrode array core cannot be maintained.In other words, when the position of the electrode within the electrode assembly is not designed from the beginning in consideration of the linear increase in the rotation amount of the positive and negative electrode core side ends, so that the circumferential position of the voltage enhancing region D 2, particularly the outer circumferential side end (B outer) of the positive electrode, is not included in the voltage prone region D 1 during 420 cycles, the circularity of the electrode assembly core cannot be maintained when the charge and discharge cycle is repeated 420 times or more. As a result, the collapsing of the electrode assembly core cannot be prevented or reduced while the cylindrical battery is being charged and discharged beyond the effective use cycles.<Cycle Test for Cylindrical #6 Sample Battery>FIG. 13 ais a CT cross-sectional photograph taken when a cylindrical battery prepared as a #6 sample (hereinafter, #6 sample battery) is in the BOL state. FIG. 13 bis a CT cross-sectional photograph taken after 420 cycle tests were performed on the #6 sample battery.Referring to FIGS. 13 aand 13 b, in the CT cross-sectional photograph, the positive electrode and the negative electrode are wound clockwise, and the negative electrode is wound in front of the positive electrode. Therefore, the negative electrode is placed centripetally with respect to the center of the core of the electrode assembly than the positive electrode.When the #6 sample battery was in the BOL state, the angle for the voltage-prone region D1 between the negative electrode core-side end (A inner) and the positive electrode core-side end (B inner) was measured to be 125.73 degrees, and the angle for the voltage-boosted region D 2 between the negative electrode outer-circumferential-side end (A outer) and the positive electrode outer-circumferential-side end (B outer) was measured to be 16.4 degrees. In addition, circularity of the electrode array core was calculated to be 93.34%.For the #6 sample battery, when 420 cycle tests were continuously performed, the angle for the voltage susceptible region D 1 between the negative electrode core-side end (A inner) and the positive electrode core-side end (B inner) was measured to be 140.61 degrees, and the angle for the voltage enhancing region D2 between the negative electrode outer circumferential side end (A outer) and the positive electrode outer circumferential side end (B outer) was measured to be 15.74 degrees.The negative electrode core side end (A inner) and the positive electrode core side end (B inner) were rotated significantly counterclockwise compared to the BOL state. The rotation amount of the negative electrode core side end (Ainner) was relatively larger than the rotation amount of the positive electrode core side end (Binner), and as a result, the angle of the stress-prone region D 1 was increased by 14.88 degrees compared to the BOL state.The negative electrode outer circumferential side end (A outer) and the positive electrode outer circumferential side end (B outer) hardly rotate compared to the BOL state. In measurements, the angle of the voltage boost region D 2 was reduced by 0.66 degrees compared to the BOL state. Since the operator's manual error is involved in measuring the angle, the reduction of the angle of the voltage boosting region D 2 is not reasonable.Meanwhile, the CT cross-sectional photograph may be classified into the first semicircular region (CL 1) and the second semicircular region (CL 2) based on the diametrical line segment (O 1 O 2) passing through the center of the electrode array core and being perpendicular to the straight line dividing the circumferential angle of the stress-prone region D 1 into two equal angles.The position of the stress-prone portion D 1 was continuously held within the first semicircular portion (CL 1) while 420 cycles of charging and discharging were performed.The stress enhancing region D 2 starts to overlap with the stress susceptible region D1 from the middle of the cycle test, and completely overlaps with the stress susceptible region D 1. after 420 cycles. The arrangement of the voltage-prone region D 1 and the voltage-boosting region D 2, which is applied to the #6 sample battery, does not correspond to the embodiment of the present disclosure. This is because a voltage is concentrated in the core of the electrode assembly because the voltage-prone region D 1 and the voltage-boosting region D 2 overlap from the middle of the cycle test to the later part of the cycle test.After 420 cycles of charging and discharging, circularity of the electrode array core was calculated to be 87.15%, which was decreased by about 6.19% as compared with circularity of 93.34% in the BOL state. This decrease in circularity is a reasonable decrease as compared with the #1 sample battery and the #2 sample battery. Therefore, the electrode coil rotates in the 3 o'clock to 7 o'clock direction on the CT cross-sectional photograph obtained after 420 cycles are deformed to the extent that its curvature can be recognized with the naked eye. Therefore, when the #6 sample battery is additionally charged and discharged over 420 times, there is a high possibility of the core collapsing.The cycle test results for the #6 sample battery support that when the positions of the voltage prone portion D 1 and the voltage boosting portion D 2 in the circumferential direction are not intentionally designed according to the embodiments of the present disclosure, the circularity of the electrode array core cannot be maintained.In other words, when the position of the electrode within the electrode assembly is not designed from the beginning in consideration of the linear increase in the rotation amount of the positive and negative electrode core side ends, so that the circumferential position of the voltage enhancing region D 2, particularly the outer circumferential side end (B outer) of the positive electrode, is not included in the voltage prone region D 1 during 420 cycles, the circularity of the electrode assembly core cannot be maintained when the charge and discharge cycle is repeated 420 times or more. As a result, the collapsing of the electrode assembly core cannot be prevented or reduced while the cylindrical battery is being charged and discharged beyond the effective use cycles.As can be seen from the above charge and discharge cycle test, when the electrode assembly has a structure wound in a jelly roll form, when the end positions of the negative electrode and the positive electrode in the core and the outer periphery are intentionally designed from the beginning to correspond to the embodiment of the present disclosure, the circularity of the electrode assembly core can be maintained without significant change even when the cylindrical battery is charged and discharged for 200 cycles or more, 300 cycles or more, 400 cycles or more, 700 cycles or more, or up to 900 cycles.In a cylindrical battery including an electrode assembly wound in a jelly roll shape, the angle at which the positive electrode end and the negative electrode end are rotated along the circumferential direction varies depending on various factors such as the positive electrode active material, the negative electrode active material, the diameter of the electrode assembly, the thickness of the positive electrode and the negative electrode, the number of winding turns of the positive electrode and the negative electrode, etc. Therefore, according to the present disclosure, the cylindrical battery can be configured and manufactured as follows.First, the specifications (diameter and height) of the cylindrical battery, specifications for all materials involved in the electrochemical reaction, and the effective cycle of use are determined. The effective use cycle can be determined appropriately in consideration of the intended use of the cylindrical battery. The effective usage cycle can be selected arbitrarily as 200 cycles or more, 300 cycles or more, 400 cycles or more, 500 cycles or more, 600 cycles or more, 700 cycles or more, 800 cycles or more, or 900 cycles or more. Next, a cylindrical sample battery is manufactured using a process known in the art, and the cylindrical sample battery is activated to enter the BOL state.Subsequently, while conducting a charge and discharge cycle test exceeding the effective use cycle for the cylindrical sample battery, the rotation amount of the electrode is measured according to the increase of the cycle number, as shown in FIG. 9. The amount of rotation of the electrode may be determined by obtaining CT cross-sectional photographs of the cylindrical battery at regular cycle intervals during the cycle test and then analyzing the CT cross-sectional photographs.Once the electrode rotation amount is determined according to the increase in the cycle number, the initial angles of the voltage-prone portion and the voltage-boosted portion are determined as the first winding design condition, and the initial separation angle between the two portions in the circumferential direction may be determined such that the voltage-boosted portion, in particular, the outer circumferential side end (Bouter) of the positive electrode thereof does not overlap the inner portion of the voltage-prone portion while the cylindrical battery is repeatedly charged and discharged until the effective use cycle can be determined as the second winding design condition.Then, the electrode assembly may be wound according to the determined winding design conditions, and a cylindrical battery may be manufactured using the wound electrode assembly. The cylindrical battery manufactured in this manner can maintain circularity of the electrode array core without significant change even when it is repeatedly charged and discharged up to the effective cycle of use.In the present disclosure, a positive electrode active material coated on the positive electrode and a negative electrode active material coated on the negative electrode may use any active material known in the art without limitation.In an example, the positive electrode active material may include an alkali metal compound expressed by a general formula A[A x M y] O 2+z (A includes at least one element selected from Li, Na, and K; M includes at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru, and Cr; o≤x, 1≤x+y≤2, 0.1≤z≤2; and the stoichiometric coefficients x, y, z, and M are selected so that the compound maintains electrical neutrality).In another example, the positive electrode active material may be an alkali metal compound xLiM 1 O 2-(1- x)Li 2 M 2 O 3 disclosed in US 6,677,082, US 6,680,143 et al., wherein M 1 includes at least one element having an average oxidation state 3; M 2 includes at least one element having an average oxidation state 4; and o≤x≤1).In still another example, the positive electrode active material may be lithium metal phosphate expressed by a general formula of Li a M 1x Fe 1-x M 2y P 1-y M 3z O 4-z (M 1 includes at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, and Al; M 2 includes at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V, and S; M 3 includes a halogen element optionally including F; o<a≤2, o≤x≤1, o≤y<1, o≤z<1; the stoichiometric coefficients a, x, y, z, M 1, M 2 and M 3 are selected such that the compound maintains electrical neutrality) or Li 3 M 2( PO 4)3[ M includes at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg and Al].Preferably, the positive electrode active material may include primary particles and / or secondary particles in which the primary particles are aggregated.In an example, the negative electrode active material may use carbon material, lithium metal or a lithium metal compound, a silicon-based compound, tin or a tin compound, or the like. Metal oxides such as TiO2and SnO2having a potential of less than 2 V may also be used as the negative electrode active material. As the carbon material, low crystalline carbon, high crystalline carbon or the like may be used.The negative electrode active material may include a silicon-based active material, the silicon-based active material may include one or more selected from the group consisting of Si particles, silicon oxide (e.g., SiOx(0<x<2)), SiC, and a Si alloy. In one example, the silicon-based active material (e.g., SiO) may be added in an amount of 0.5 wt % to 15 wt %, 1 wt % to 10 wt %, 2 wt % to 6 wt %, or 2 wt % to 5 wt % of the entire negative electrode active material. When the amount of the silicon-based active material (e.g., SiO) is controlled within the numerical range, the addition of SiO can increase the capacity of the negative electrode while suppressing the volume expansion of the negative electrode that affects the collapse of the core of the electrode assembly to a manageable level.The separator may use a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, or the like, or laminates thereof. As another example, the separator may use a usual porous nonwoven fabric, for example, a nonwoven fabric made of high melting point glass fiber, polyethylene terephthalate fiber, or the like.At least one surface of the separator may include an inorganic particle coating layer. It is also possible that the separator itself is made of a coating layer of inorganic particles. The particles forming the coating layer may have a structure coupled with a binder such that interstitial volumes exist between adjacent particles.The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. The inorganic particles may include at least one material selected from the group consisting of Pb(Zr,Ti)O 3( PZT), Pb 1-x La x Zr 1-y Ti y O 3( PLZT), PB(Mg 3 Nb 2 / 3) O 3, PbTiO 3( PMN-PT), BaTiO3, hafnium oxide (HfO2), SrTiO3, TiO 2, Al 2 O 3, ZrO 2, SnO 2, CeO 2, MgO, CaO, ZnO and Y 2 O 3 are selected.The electrolyte may be a salt having a structure such as A + B -. A + contains an alkaline metal cation such as Li +, Na + or K +, or a combination thereof. B - contains at least one anion selected from the group consisting of F -, Cl -, Br, I -, NO 3-, N(CN) 2-, BF 4-, ClO 4-, AlO 4-, AlCl 4-, PF6NER503_, SbF6NER505_, ASF6NER507_, bf_ner508_C 2 O 4-, BC 4 O 8-, ( CF 3)2 PF 4-, ( CF 3)3 PF 3-, ( CF 3)4 PF 2-, ( CF3)5PF-, (CF3)6P-, CF3SO3NER535_, C 4 F 9 SO 3-, CF 3 CF 2 SO 3-, ( CF 3 SO 2)2 N -, ( FSO 2)2 N-, CF3CF2(CF3)2CO-, (CF3SO2)2CH-, (SF5)3C-, (cf_ner563_so_ner564_)_ner565_c -, CF 3( CF 2)7 SO 3-, CF 3 CO 2-, CH 3 CO 2-, SCN - and (CF 3 CF2SO2)2N-.The electrolyte may also be dissolved in an organic solvent. The organic solvent may use propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), γ-butyrolactone, or a mixture thereof.The structure of the electrode and the electrode assembly used for manufacturing the cylindrical battery according to an embodiment of the present disclosure will be described below. Next, the structure of the cylindrical battery according to an embodiment of the present disclosure will also be described in detail.The configuration of the electrode, the electrode assembly, and the cylindrical battery described in the embodiments, together with the configuration of the position of the electrode end described above, is effective in preventing or mitigating the collapsing of the electrode assembly core. In particular, the welding structure of the current collector using the bending surface area formed by bending the uncoated portion of the positive electrode and / or the negative electrode can firmly fix the position of the positive electrode and / or the negative electrode, thereby reducing the degree of freedom of rotation of the electrode near the core of the electrode assembly.FIG. 14 ais a plan view showing a structure of an electrode 40 according to the first embodiment of the present disclosure.Referring to FIG. 14 a, the electrode 40 of the first embodiment includes a current collector 41 made of a metal foil and an active material layer 42. The metal foil may be a conductive metal such as aluminum or copper, and is appropriately selected according to the polarity of the electrode 40. The active material layer 42 is formed on at least one surface of the current collector 41. The active material layer 42 is formed along the winding direction X. The electrode 40 includes an uncoated portion 43 at the long side end in the winding direction X. The uncoated portion 43 is a portion of the current collector 41 that is not coated with the active material. The region of the current collector 41 where the active material layer 42 is formed may be referred to as an active material portion.In the electrode 40, the width of the active material portion in the short-side direction of the current collector 41 may be 50 mm to 120 mm, and the length of the active material portion in the long-side direction of the current collector 41 may be 3 m to 5 m. Therefore, the ratio of the short side to the long side of the active material portion may be 1.0% to 4.0%.Preferably, in the electrode 40, the width of the active material portion in the short-side direction of the current collector 41 may be 60 mm to 70 mm, and the length of the active material portion in the long-side direction of the current collector 41 may be 3 m to 5 m. Therefore, the ratio of the short side to the long side of the active material portion may be 1.2% to 2.3%.The ratio of the short side to the long side of the active material portion is significantly less than 6% to 11%, that is, the ratio of the short side to the long side of the active material portion of an electrode used in a cylindrical battery having a shape factor of 1865 or 2170.Preferably, the current collector 41 may have an elongation of 1.5% to 3.0% and a tensile strength of 25 kgf / mm 2 to 35 kgf / mm 2. The elongation and tensile strength can be measured according to the measurement method of IPC-TM-650. The electrode 40 is manufactured by forming an active material layer 42 on the current collector 41 and then compressing it. When compressed, the area of the uncoated portion 43 and the area of the active material layer 42 have different strains. Therefore, swelling is formed on the electrode 40 after the compression, and when the electrode 40 is longer, the swelling is heavier.Optimizing the elongation and tensile strength of the current collector 41 reduces the post-compression bulging length to less than 20 mm when the length of the electrode 40 is about 4 m. The bulging length is a maximum displacement amount of the electrode 40 in the winding direction X when the swollen electrode 20 is spread. The maximum displacement amount may be measured at the end of the outer periphery. Since the electrode 40 in which the elongation and tensile strength of the current collector 41 are optimized has a small bulging length, meandering defects do not occur during the notching process of the uncoated portion 43 or the winding process of the electrode 40.The current collector 41 is more likely to be broken when the elongation is smaller. When the elongation of the current collector 41 is less than 1.5%, the rolling process efficiency of the current collector 41 is reduced, and thus separation may occur in the current collector 41 when the electrode 40 coated with the active material layer 42 is pressed onto the current collector 41. Meanwhile, when the elongation of the current collector 41 exceeds 3.0%, the bulging length greatly increases as the elongation of the active material portion of the electrode 40 increases. When the tensile strength of the current collector 41 is less than 25 kgf / mm 2 or more than 35 kgf / mm 2 the electrode process efficiency of the electrode 40 is deteriorated.The bulging phenomenon is particularly problematic for positive electrode current collectors made of aluminum foil. According to the present disclosure, the bulging phenomenon can be suppressed by using an aluminum foil having an elongation of 1.5% to 3.0% and a tensile strength of 25 kgf / mm 2 to 35 kgf / mm 2 as the current collector. It is desirable to form an active material layer on the current collector and use it as a positive electrode.Preferably, an insulating coating layer 44 may be formed at a boundary between the active material layer 42 and the uncoated portion 43. The insulating coating layer 44 is formed such that at least a part thereof overlaps with the boundary between the active material layer 42 and the uncoated portion 43. The insulating coating layer 44 prevents a short circuit between two electrodes having different polarities and facing each other with a separator interposed therebetween. The insulating coating layer 44 may cover a boundary between the active material layer 42 and the uncoated portion 43 with a width of 0.3 mm to 5 mm. The width of the insulating coating layer 44 may vary along the winding direction of the electrode 40. The insulating coating layer 44 may include a polymer resin and an inorganic filler such as Al 2 O 3. Since the portion of the current collector 41 covered by the insulating coating layer 44 is not a region coated with an active material layer, it can be regarded as an uncoated portion.The uncoated portion 43 includes a core-side uncoated portion B 1 adjacent to the core of the electrode assembly, an outer peripheral-side uncoated portion B 3 adjacent to the outer periphery of the electrode assembly, and an intermediate uncoated portion B 2 disposed between the core-side uncoated portion B 1 and the outer peripheral-side uncoated portion B 3.The core-side uncoated portion B 1, the outer peripheral-side uncoated portion B 3, and the intermediate uncoated portion B 3 may be respectively defined as an uncoated portion in a region adjacent to the core, an uncoated portion in a region adjacent to the outer periphery, and an uncoated portion of the remaining region other than the above regions when the electrode 40 is wound into a jelly roll type electrode assembly.Hereinafter, the core-side uncoated portion B 1, the outer peripheral-side uncoated portion B 3, and the intermediate uncoated portion B 2 are referred to as a first portion, a second portion, and a third portion, respectively.In one example, the first portion B 1 may be an uncoated portion of an electrode region including the innermost winding turn, and the second portion may be an uncoated portion of an electrode region including the outermost winding turn. The winding turn may be counted based on the core-side end of the electrode assembly.In another example, the boundary of B 1 / B 2 may be appropriately defined as a point at which the height (or the change pattern) of the uncoated portion substantially changes as it goes from the core of the electrode assembly to the outer periphery, or as a point of a predetermined % based on the radius of the electrode assembly (e.g., 5% point, 10% point, 15% point, or the like of the radius).The boundary of B 2 / B 3 may be defined as a point at which the height (or the change pattern) of the uncoated portion substantially changes while going from the outer periphery of the electrode assembly to the core, or as a point of a predetermined % based on the radius of the electrode assembly (e.g., 85% point, 90% point, 95% point, or the like of the radius). When the boundary of B 1 / B 2 and the boundary of B 2 / B 3 are determined, the third portion B 2 can be automatically determined.When only the boundary of B 1 / B 2 is determined, the boundary of B 2 / B 3 may be appropriately selected at a point near the outer periphery of the electrode assembly. In one example, the second portion may be defined as an uncoated portion of a region of the electrode that forms the outermost winding turn. Conversely, when only the boundary of B 2 / B 3 is determined, the boundary of B 1 / B 2 may be appropriately selected at a point near the core of the electrode assembly. In one example, the first portion may be defined as an uncoated portion of a region of the electrode that forms the innermost winding turn.It is not excluded that another structure is disposed between the first portion B 1 and the third portion B 2. Also, it is not excluded that another structure is disposed between the third portion B 2 and the second portion B 3.In the first embodiment, the height of the uncoated portion 43 is not constant and there is a relative difference in the winding direction X. That is, the height (length in the Y-axis direction) of the second portion B 3 is 0 or more, but is relatively smaller than those of the first portion B 1 and the third portion B 2. Here, the height of each portion may be an average height or a maximum height applied below in the same manner. In the winding direction, the third portion B 2 is longer than the first portion B 1 and the second portion B 3.FIG. 14 bis a plan view showing the structure of an electrode 45 according to the second embodiment of the present disclosure.Referring to FIG. 14 b, the electrode 45 of the second embodiment is substantially the same as the first embodiment except that the height of the second portion B 3 gradually decreases toward the outer periphery.In a modification, the second portion B 3 may be deformed into a step shape in which the height decreases stepwise (see dotted line).FIG. 14 cis a plan view showing the structure of an electrode 50 according to the third embodiment of the present disclosure.Referring to FIG. 14 c, in the electrode 50 of the third embodiment, the heights of the first portion B 1 and the second portion B 3 are 0 or more, but are relatively smaller than the third portion B 2. In addition, the heights of the first portion B 1 and the second portion B 3 may be the same or different.Preferably, the height of the third portion B 2 may have a step shape gradually increasing from the core toward the outer periphery.The patterns 1 to 7 classify the third portion B 2 based on the position where the height of the uncoated portion 43 changes. Preferably, the number of the patterns, and the height (length in the Y-axis direction) and width (length in the X-axis direction) of each pattern may be adjusted to distribute the stress during bending of the uncoated portion 43 as much as possible. The stress distribution is intended to prevent the uncoated portion 43 from being torn off when the uncoated portion 43 is bent toward the core of the electrode assembly.The width (d B1) of the first portion B1 is designed by applying the condition that the core of the electrode assembly is not covered when the patterns of the third portion B2 are bent toward the core. The core means a cavity existing in the winding center of the electrode assembly.In an example, the width (d B1) of the first portion B 1 may increase in proportion to the bending length of the pattern 1. The bending length corresponds to the height of the pattern based on the bending point of the pattern.Preferably, the width (d B1) of the first portion B 1 may be set such that the width in the radial direction of the winding turns formed by the first portion B 1 is equal to or greater than the bending length of the pattern 1. In a modification, the width (d B1) of the first portion B 1 may be set such that the value obtained by subtracting the radial width of the winding turns formed by the first portion B 1 from the bending length of the pattern 1 is less than o or 10% or less of the radius of the core.In a specific example, when the electrode 60 is used to manufacture an electrode assembly of a cylindrical battery having a shape factor of 4680, the width (d B1) of the first portion B 1 may be set to 180 mm to 350 mm depending on the diameter of the core of the electrode assembly and the bending length of the pattern 1.In an embodiment, the width of each pattern may be configured to form one or more winding turns of the electrode assembly.In a modification, the height of the third portion B 2 may have a step shape in which the height increases from the core toward the outer periphery and then decreases.In another modification, the second portion B 3 may be deformed to have the same structure as the second embodiment.In yet another modification, the pattern structure applied to the third portion B 2 may be expanded to the second portion B 3 (see dotted line).FIG. 14 dis a plan view showing the structure of an electrode 60 according to the fourth embodiment of the present disclosure.Referring to FIG. 7 a, in the electrode 60 of the fourth embodiment, the first portion B 1 and the second portion B 3 have heights of o or more in the winding axis direction Y, but are relatively smaller than the third portion B 2. In addition, the heights of the first portion B 1 and the second portion B 3 in the winding axis direction Y may be the same or different.Preferably, at least a portion of the third portion B 2 may include a plurality of segments 61. The heights of the plurality of segments 61 may increase stepwise from the core toward the outer periphery. The plurality of segments 61 have a geometric shape in which the width decreases from bottom to top. Preferably, the geometric figure is a trapezoid. As will be described later, the shape of the geometric figure can be modified in various ways.The segment 61 may be formed by laser notching (laser notching). The segment 61 may be formed by a known metal foil cutting process such as ultrasonic cutting or punching.In the fourth embodiment, in order to prevent the active material layer 42 and / or the insulating coating layer 44 from being damaged during bending of the uncoated portion 43, it is preferable to provide a predetermined gap between the bottom (a portion denoted by G in FIG. 14 e ) of the cut groove between the segments 61 and the active material layer 42. This is because stress is concentrated near the bottom of the cut groove 63 when the uncoated portion 43 is bent. The gap may be varied along the winding direction of the electrode 60. The gap is 0.2 mm to 4 mm, preferably 1.5 mm to 2.5 mm. When the gap is set within the corresponding numerical range, it is possible to prevent the active material layer 42 and / or the insulating coating layer 44 near the bottom of the cut groove 63 from being damaged by the stress generated during bending of the uncoated portion 43. The gap may prevent the active material layer 42 and / or the insulating coating layer 44 from being damaged due to tolerance during notching ("notch") or cutting of the segment 61. In a direction parallel to the winding direction, the gap may be substantially the same or may vary. In the latter case, the columns of the plurality of segments may be varied individually, in a group unit, or in two or more group units along a direction parallel to the winding direction. The lower end of the cut groove 63 and the insulating coating layer 44 may be spaced apart from each other by 0.5 mm to 2.0 mm. In a direction parallel to the winding direction, the separation distance between the lower end of the cut groove 63 and the insulating coating layer 44 may be substantially the same or variable. In the latter case, the separation distances of the plurality of segments may be varied individually, in a unit group, or in two or more unit groups along a direction parallel to the winding direction. When the electrode 60 is wound, the end of the insulating coating layer 44 in the winding axis Y direction may be in the range of -2 mm to 2 mm along the winding axis direction with respect to the end of the separator. The insulating coating layer 44 can prevent a short circuit between two electrodes having different polarities and facing each other with a separator interposed therebetween, and can promote a bending point when the segment 61 is bent. In order to improve the short-circuit prevention effect between the two electrodes, the insulating coating layer 44 may be exposed to the outside of the separator. In addition, in order to further maximize the effect of preventing a short circuit between the two electrodes, the width of the insulating coating layer 44 may be increased so that the end of the insulating coating layer 44 is located above the lower end of the cut groove 63 in the direction of the winding axis Y. In an embodiment, the end of the insulating coating layer 44 in the winding axis direction may be in a range of -2 mm to +2 mm with respect to the lower end of the cut groove 63. The thickness of the insulating coating layer 44 may be less than the thickness of the active material layer 42. In this case, a gap may exist between the surface of the insulating coating layer 44 and the separator.In one aspect, the plurality of segments 61 may form a plurality of segment groups that go from the core to the outer periphery. The width and / or height and / or separation distance of segments belonging to the same segment group may be substantially the same. Preferably, the width, height and separation distance of the segments belonging to the same segment group may be substantially the same.Preferably, the width, height and separation distance of the segments belonging to the same segment group may be substantially the same.In another aspect, the separation distances of the plurality of segments may gradually or stepwise increase from the core toward the outer periphery in one group unit or in two or more group units, or vice versa.In yet another aspect, the separation distances of the plurality of segments from the core toward the outer periphery may gradually or stepwise increase in a group unit or in two or more group units, and then gradually or stepwise decrease, or vice versa.According to still another aspect, in the plurality of segments, the gap between the lower end of the cut groove 63 and the insulating coating layer 44 or the active material layer 42 may gradually or stepwise increase from the core toward the outer periphery, or vice versa.According to still another aspect, in the plurality of segments, the gap between the lower end of the cut groove 63 and the insulating coating layer 44 or the active material layer 42 may gradually or stepwise increase or gradually or stepwise decrease from the core toward the outer periphery, or vice versa.FIG. 14 eis a diagram showing the definitions of width D, height H, and separation distance P of a trapezoidal segment 61 according to an embodiment of the present disclosure.Referring to FIG. 14 e, the width (D), the height (H), and the separation distance (P) of the segment 61 are designed to prevent the uncoated portion 43 near the bending point from being torn off during the bending of the uncoated portion 43 and to prevent abnormal deformation of the uncoated portion 43 while sufficiently increasing the number of overlapping layers of the uncoated portion 43 to ensure sufficient welding strength.The segment 61 is bent at the line G passing through the bottom of the cut groove 63 or at the top thereof. The cut groove 63 enables smooth and easy bending of the segment 61 in the radial direction of the electrode assembly.The width (D) of the segment 61 is defined as the length between two points at which two straight lines extending from both sides 63b of the segment 61 meet a straight line extending from the bottom 63a of the cut groove 63. The height (H) of the segment 61 is defined as the shortest distance between the top edge of the segment 61 and a straight line extending from the bottom 63 aof the cut groove 63. The separation distance (P) of the segment 61 is defined as the length between two points at which a straight line extending from the bottom 63 aof the cut groove 63 meets straight lines extending from both sides 63 bconnected to the bottom 63 a. When the side 63 band / or the bottom 63 aare curved, the straight line may be replaced with a tangent extending from the side 63 band / or the bottom 63 aat an intersection where the side 63 band the bottom 63 acomes.Preferably, the width (D) of the segment 61 is 1 mm or more. If D is less than 1 mm, when the segment 61 is bent toward the core, an area or a void (gap) may occur in which the segments 61 do not overlap enough to sufficiently ensure welding strength.Preferably, the width (D) of the segments 61 can be adaptively adjusted depending on the radius of the winding turn in which the segments 61 are located, so that the segments 61 overlap well in the radial direction when the segments 61 are bent toward the core of the electrode arrangement.FIG. 14 fis a diagram showing an arc (A 1 A 2) formed by a lower end (line D ab in FIG. 14 e) of the segment 61, wherein the width D of the segment 61 is defined with respect to the center O of the core of the electrode assembly when the electrode 60 is wound, according to an embodiment of the present disclosure.Referring to FIG. 14f, the arc (A 1 A 2) has a length corresponding to the width (D) of the segment 61 and has a circumferential angle (Φ) with respect to the center of the core of the electrode assembly. The circumferential angle (Φ) may be defined as the angle between two line segments connecting both ends of the arc (A 1 A 2) and the center O of the core on a plane perpendicular to the winding axis passing through the arc (A 1 A 2).When the length of the arc (A 1 A 2) of the segment 61 is the same, the circumferential angle (Φ) decreases as the radius (r) of the winding turn in which the segment 61 is located increases. Conversely, if the circumferential angle (φ) of the segment 61 is equal, the length of the arc (A 1 A 2) increases proportionately as the radius (r) of the winding turn in which the segment 61 is located increases.The circumferential angle (Φ) affects the bending quality of the segment 61. in the drawing, a solid arrow indicates a direction of the force applied to bend the segment 61, and a dotted arrow indicates a direction in which the segment 61 is bent. The bending direction is a direction toward the center O of the core.The circumferential angle (Φ) of the segment 61 may be 45 degrees or less, preferably 30 degrees or less, depending on the radius (r) of the winding turn in which the segment 61 is located, in order to improve bending uniformity and prevent cracking.According to an aspect, the circumferential angle (Φ) of the segment 61 along the radial direction of the electrode assembly may gradually or stepwise increase or decrease within the above numerical range. According to another aspect, the circumferential angle (Φ) of the segment 61 along the radial direction of the electrode assembly may gradually or stepwise increase or gradually or stepwise decrease within the above numerical range, or vice versa. In another aspect, the circumferential angle (Φ) of the segment 61 along the radial direction of the electrode assembly may be substantially equal within the above numerical range.According to experiments, when the circumferential angle (Φ) of the segment 61 exceeds 45 degrees, the bending shape of the segment 61 is not uniform. The difference between the force applied to the central part of the segment 61 and the force applied to the side part increases, so that the compression of the segment 61 is not uniform in the circumferential direction. In addition, when the pressing force for bending uniformity is increased, cracks may occur in the uncoated portion 43 in the vicinity of the cut groove 63.According to an embodiment, the circumferential angles (Φ) of the segments 61 included in the electrode 60 are substantially equal, and the widths of the segments 61 may increase proportionally as the radius (r) of the winding turn in which the segment 61 is located increases. The term "substantially the same" means completely identical or with a variance of less than 5%.For example, when the radius of the electrode assembly is 22 mm, the radius of the core is 4 mm, the segments 61 are arranged starting from the winding turn located at the point where the radius is 7 mm, when the circumferential angles (Φ) of the segments 61 are uniform at 28.6 degrees, the widths (D) of the segments 61 may increase proportionally according to the radius (r) of the winding turn where the segments 61 are located, as shown in Table 1 below. That is, the widths of the segments 61 may increase by 0.5 mm at substantially the same rate every time the radius (r) of the winding turn increases by 1 mm Preferably, the width D(r) of the segment 61 located in a winding turn having a radius of r based on the core center O of the electrode assembly may be determined within a range satisfying Formula 1 below.Preferably, the widths D(r) of the plurality of segments 61 in the winding direction may gradually or stepwise increase as the radius r of the winding turn in which the segment 61 is located increases based on the core center of the electrode assembly, or vice versa.In another aspect, the widths D(r) of the plurality of segments 61 in the winding direction may gradually or stepwise increase in the range of 1 mm to 11 mm as the radius r of the winding turn in which the segment 61 is located increases based on the core center of the electrode assembly, or vice versa.In yet another aspect, the widths D(r) of the plurality of segments 61 in the winding direction may gradually or stepwise increase and then gradually or stepwise decrease as the radius r of the winding winding in which the segment 61 is located increases based on the core center of the electrode assembly, or vice versa.According to still another aspect, the widths D(r) of the plurality of segments 61 in the winding direction may gradually or stepwise increase, and then gradually or stepwise decrease in the range of 1 mm to 11 mm as the radius r of the winding winding winding in which the segment 61 is located increases based on the core center of the electrode assembly, or vice versa.In yet another aspect, the rate at which the widths D(r) of the segments 61 change as the radius r of the winding turn in which the segment 61 is located increases may be the same or different.In yet another aspect, the rate at which the widths D(r) of the segments 61 change in the range of 1 mm to 11 mm as the radius r of the winding turn in which the segment 61 is located increases may be the same or different.Referring again to FIG. 14 e, the height (H) of the segment may be 612 mm or more. When D2 is less than 2 mm, when the segment 61 is bent toward the core, there may occur an area or a void (gap) in which the segments 61 do not overlap enough to sufficiently ensure welding strength.The height (H) of the segment 61 may be determined by applying the condition that the segment 61 does not block the core when bent toward the core. Preferably, the height (H) of the segment 61 may be adjusted so that 90% or more of the diameter of the core can be opened to the outside.Preferably, the heights (H) of the segments 61 may increase from the core toward the outer periphery depending on the radius of the winding turn and the radius of the core in which the segments 61 are located.In an embodiment, when the heights (H) of the segments 61 increase stepwise over N stages from h 1 to h N as the radius of the winding turn increases, assuming that the k-th height of the segment 61 (k is a natural number from 1 to N) is h k the initial radius of the winding turn including the segment 61 having the height hk is r k and the radius of the core r is c the heights h 1 to h N of the segments 61 may be determined to satisfy Formula 2 below.When the heights (h k) of the segments 61 satisfy Formula 2, even when the segments 61 are bent toward the core, 90% or more of the diameter of the core may be opened outward.In one example, the radius of the entire winding turns of the electrode 60 is 22 mm, the heights of the segments 61 start at 3 mm, and the heights of the segments 61 are sequentially increased to 3 mm, 4 mm, 5 mm, and 6 mm whenever the radius of the winding turn including the segment 61 increases by 1 mm, and the heights in the remaining winding turns can be kept substantially identical at 6 mm. That is, among the radii of the entire winding turns, the radial width of the height-variable region of the segment 61 is 3 mm, and the remaining radial region corresponds to the height uniform region.In this case, when α is 1 and the condition of the same sign is applied in the proper inequality, the initial radius r 1, r 2, r 3, r 4 of the winding turns including the segments 61 having heights of 3 mm, 4 mm, 5 mm and 6 mm depending on the radius (r c) of the core of the electrode assembly may be as shown in Table 2 below. TABLE 2 TABLE 2Core radius (r c) ( mm)25 (r 1)6 (r 2)7 (r 3)8 (r 4)2,55,5 (r 1)6,5 (r 2)7,5 (r 3)8,5 (r 4)36 (r 1)7 (r 2)8 (r 3)9 (r 4)3,56,5 (r 1)7,5 (r 2)8,5 (r 3)9,5 (r 4)47 (r 1)8 (r 2)9 (r 3)10 (r 4)When the segments 61 are arranged at the radius positions shown in Table 2, the core is not blocked by the segments 61 even if the segments 61 are bent toward the core. Meanwhile, r 1, r 2, r 3, r 4, shown in Table 1, may be shifted toward the core according to the value of α. In one example, if α is 0.90, r 1, r 2, r 3, r 4 may be shifted towards the core by 10% of the core radius. In this case, when the segment 61 is bent toward the core, 10% of the core radius is blocked by the segment 61. r 1, r 2, r 3, r 4, shown in Table 1, are limit values of the position at which the segment 61 starts. Therefore, the position of the segment 61 may be shifted toward the outer periphery by a predetermined distance instead of the radius shown in Table 2.FIG. 14g is a diagram schematically showing the relationship of the heights h 1, h 2, h 3, h 4 of the segments 61, the core radius (r c) and the radii r 1, r 2, r 3, r 4 of the winding turns where the segments 61 start to appear.Referring to Table 2 and FIG. 14g taken together, for example, when the radius (r c) of the core C is 3 m, the initial radii r 1, r 2, r 3 and r 4 of the winding turns including the segments 61 may be 3 mm (h 1), 4 mm (h 2), 5 mm (h 3) and 6 mm (h 4) 6 mm, 7 mm, 8 mm and 9 mm in height, respectively, and the heights of the segments 61 may be maintained at 6 mm from the radius 9 mm to the last winding turn. In addition, the segment 61 may not be included in the winding turn having a radius smaller than 6 mm (r 1). In this example, since the segment 61 having a height of 3 mm (h 1), which is closest to the core C, is located from the winding turn having a radius of 6 mm, even if the segments 61 are bent toward the core C, the segments 61 cover only the radial range of 3 mm to 6 mm and do not substantially block the core C. According to the α value of Formula 2, the position of the segment 61 can be shifted toward the core C within 10% of the core radius (r c).According to another embodiment, the height of the segment 61 may increase at the same or different rate as the initial radius r of the winding turn in which the segment 61 is located increases based on the core center of the electrode assembly.Preferably, the height (H) of the segment 61 satisfies Formula 2, and at the same time, the maximum height of the segment 61 may be restricted.FIG. 14 his a conceptual diagram for determining a maximum value (h max) for the height (H) of the segment 61 in a variable segment height range of the segment 61.Referring to FIG. 14 h, in the winding structure of the electrode assembly, the electrode (E 1), which includes the segment 61, faces the electrode (E 2) having opposite polarity with the separator S interposed therebetween in the radial direction. Both surfaces of the electrode (E 1) are coated with an active material layer (E 1,aktiv) and both surfaces of the electrode (E 2) are also coated with an active material layer (E 2,aktiv). For electrical insulation, the end (S end) of the separator S may extend further outward from the end (E 2,end) of the electrode (E 2) to a length corresponding to the insulation gap (W gap). In addition, the end of the electrode (E 1) does not extend further outward beyond the end of the electrode (E 2) for electrical insulation. Therefore, a region corresponding to the insulation gap (W gap) should be attached to the lower end of the uncoated portion 43. When the electrodes (E 1, E 2) and the separator S are wound, the end (S end) of the separator S also makes meandering. Therefore, in order for the segment 61 to be exposed to the outside of the separator S, the region (W margin,min), which corresponds to a minimum meandering edge of the separator S, needs to be assigned to the uncoated portion 43. In addition, to cut the segment 61, a minimum cut scrap margin (W serap,min) should be associated with the end of the current collector foil. Therefore, the maximum height (h max) of the segment 61 in the variable height range of the segment 61 can be determined by Formula 3 below. In Formula 3, W foil corresponds to the width of the current collector foil before the current collector foil is cut.Preferably, the insulation gap W may be gap0,2 mm to 6 mm when the first electrode is a positive electrode. In addition, the insulation gap W may be gap0,1 mm to 2 mm when the first electrode is a negative electrode.Preferably, the minimum scrap cutting edge W may be scrag,min1,5 mm to 8 mm. The minimum scrap cutting margin (W serap,min) cannot be assigned depending on the process of forming the segment 61. For example, the cut groove 63 may be formed such that the upper edge of the segment 61 and the upper edge of the current collector foil coincide with each other. In this case, in Formula 3, W may be serap,min o.Preferably, the minimum meandering edge W margin,min of the separator can be o mm to 1 mm.In one example, the minimum scrap cutting edge (W may be serap,min) 1,5 mm and the minimum meandering edge (W margin,min) of the separator S may be 0.5 mm. Under these conditions, when the width (W foil) of the current collector foil before forming the segment 61 is 8 mm to 12 mm and the insulation gap (W is gap) 0,6 mm, 0.8 mm, and 1.0 mm, the maximum height (h max) of the segment 61 can be calculated using Formula 3 as in Table 3 below. TABLE 3 TABLE 3Width of current collector foil (mm)85,45,2596,46,26107,47,27118,48,28129,49,29With reference to Table 3, the maximum height (h max) of the segment 61 in the variable height range of the segment 61 may be set to 10 mm. Therefore, the height of the segment 61 in the variable height range of the segment 61 satisfies Formula 2, and may gradually increase in the range of 2 mm to 10 mm along the radial direction of the electrode assembly.Referring back to FIG. 14 e, the separation distance (P) of the segment 61 may be set in the range of 0.05 mm to 1 mm. When the separation distance (P) is less than 0.05 mm, cracks may occur in the uncoated portion 43 near the lower end of the cut groove 63 due to stress when the electrode 60 moves in the winding process or the like. Meanwhile, when the separation distance (P) exceeds 1 mm, there may occur an area or a void (gap) in which the segments 61 do not overlap enough to sufficiently ensure the welding strength when the segment 61 is bent.Meanwhile, when the current collector 41 of the electrode 60 is made of aluminum, it is more preferable to set the separation distance (P) to 0.5 mm or more. When the separation distance (P) is 0.5 mm or more, even when the electrode 60 moves at a speed of 100 mm / s or more under a stress of 300 gf or more in the winding process or the like, cracks can be prevented from occurring at the bottom of the cut groove 63.According to the experimental results, when the current collector 41 of the electrode 60 is an aluminum foil having a thickness of 15 μm and the separation distance (P) is 0.5 mm or more, no cracks are generated at the bottom of the cut groove 63 when the electrode 60 moves under the above movement conditions.As shown in FIG. 14 e, a cut groove 63 is disposed between two segments 61 adjacent in the winding direction X. The cut groove 63 corresponds to a space generated by removing the uncoated portion 43. Preferably, edges at both ends of the lower portion of the cut groove 63 have a round shape. That is, the cut groove 63 has a substantially flat bottom portion 63 aand a round portion 63 c. The round portion 63 cconnects the bottom portion 63 aand the side 63 bof the segment 61. In this case, the sides 63 bof the segments 61 can be smoothly connected by the arc shape of the bottom portion 63 a.The radius of curvature of the round portion 63 cmay be greater than o and less than or equal to 0.5 mm, preferably greater than o and less than or equal to 0.1 mm, more preferably 0.01 mm to 0.05 mm. When the radius of curvature of the round portion 63 creaches the above numerical range, it is possible to prevent cracks from occurring in the lower portion of the cut groove 63 while the electrode 60 moves in the winding process or the like.The lower inner angles (θ) of the plurality of segments 61 may increase from the core toward the outer periphery. In an example, the lower inner angles (θ) of the plurality of segments 61 may gradually or stepwise increase from the core toward the outer periphery. The lower internal angle (θ) is an angle between a straight line extending from the bottom 63 aof the cut groove 63 and a straight line extending from the side portion 53 bof the segment 61. When the segment 61 is symmetrical in the left and right directions, the lower inner angles (θ) of the left and right sides are substantially equal.As the radius of the electrode assembly increases, the radius of curvature increases. When the lower internal angle (θ) of the segment 61 increases as the radius of the electrode assembly increases, the stress generated in the radial direction and the circumferential direction when the segment 61 is bent may be relaxed. In addition, as the lower inner angle (θ) increases as the segment 61 is bent, the area overlapping with the segment 61 on the inner side and the number of the overlapping layers increase, so that the welding strength in the radial direction and the circumferential direction can be secured smoothly and the bending surface area can be formed flat.Preferably, the lower internal angle (θ) can be determined by the radius of the winding turn in which the segment 61 is located and the width (D) of the segment 61.FIG. 14 iis a schematic diagram for explaining the formula that determines a lower inner angle (θ) of the segment 61.Referring to FIG. 14 i, ideally, the sides of the segment 61 coincide with the line segment AE and the line segment DE that connect the core center (E) to both end points A and D of the line segment AD corresponding to the width (D) of the segment 61.When the side of the segment 61 extends in the most ideal direction, assuming that the line segment EF is approximately equal to the line segment AE and the line segment DE, the lower internal angle (θ refer) of the segment 61 can be determined approximately from the width (D) of the segment 61 and the radius (r) of the winding turn in which the segment 61 is located using Formula 4 below.The angle of Formula 4 is an ideal criterion angle for the lower internal angle (θ refer) of the segment 61. Meanwhile, there is a separation distance (P) between adjacent segments 61 located in the same winding turn. The length of the separation distance (P) is expressed as p. Since the separation distance (P) exists between adjacent segments 61, a tolerance of 50% of the separation distance (p) can be given to the lower internal angle (θ). That is, the width of the top BC of the segment 61 can be increased by a maximum of p / 2 toward the top B'C'. The lower internal angle (θ') with the reflected tolerance can be expressed as in Formula 5 below. The lower internal angle (θ refer) is the ideal criterion angle BAG, and the lower internal angle (θ') is the angle B'AG' reflecting the tolerance according to the separation distance (p). In Formula 5, H is the height of the segment 61, and p corresponds to the separation distance.Preferably, the lower internal angle (θ) of the segment 61 located in each winding turn of the electrode assembly may satisfy Formula 6 below. Then, when the segments 61 are bent toward the core center of the electrode assembly, the segments 61 adjacent in the circumferential direction do not interfere with each other and can be bent smoothly.In an example, when the electrode 60 forms a winding structure having a diameter of 22 mm and a core radius of 4 mm, the lower inner angle of the segment 61 may gradually or stepwise increase in the variable height range in the range of 60 degrees to 85 degrees.In another example, the lower internal angles (θ) of the plurality of segments 61 may gradually or stepwise increase from the core toward the outer periphery in one group unit or in two or more group units.Meanwhile, the left lower inner angle and the right lower inner angle of the segment 61 may not be the same. However, the lower internal angle (θ) of any side may be designed to satisfy Formula 6 described above.Referring back to FIG. 14 d, the width (d B1) of the first portion B 1 is designed such that the core of the electrode assembly is opened outward by 90% or more in diameter when the segment 61 of the third portion B 2 is bent toward the core. The width (d B1) of the first portion B 1 may increase in proportion to the bending length of the segment 61 of the group 1. The bending length corresponds to a length from the bending point to the upper end side of the segment 61. Preferably, when the electrode 60 is used to manufacture an electrode assembly of a cylindrical battery having a shape factor of 4680, the width (d B1) of the first portion B 1 may be set to 180 mm to 350 mm depending on the diameter of the core of the electrode assembly and the height of the segment 61 included in the group 1.The bending point of the segment 61 may be set at a line passing through the lower end of the cut groove 63 or a point spaced upward from the line by a predetermined distance. When the segment 61 is bent toward the core at a point spaced from the lower end of the cut groove 63 by a certain distance, the segments overlap better in the radial direction. When the segments 61 are bent, a segment on an outer side presses a segment on an inner side with respect to the center of the core. At this time, when the bending point is spaced from the lower end of the cut groove 63 by a predetermined distance, the segment on the inner side in the winding axis direction is pressed by the segment on the outer side, and the segments overlap better. The separation distance of the bending point may preferably be 1 mm or less. Since the minimum height of the segment is 2 mm, the ratio of the separation distance of the bending point to the minimum height may be 50% or less.In an embodiment, the width of each segment group may be designed to form the same winding turn of the electrode assembly. Here, the winding turn may be counted based on the end of the first portion B 1 when the electrode 60 is in a wound state.In another modification, the width of each segment group may be configured to form at least one winding turn of the electrode assembly.In yet another modification, the width and / or height and / or separation distance of the segments 61 belonging to the same segment group may be gradually and / or stepwise and / or irregularly increased or decreased within the group or between the adjacent groups.Groups 1 to 8 are only examples of segment groups included in the third section B 2. The number of the groups, the number of the segments 61 included in each group, and the width of the group may preferably be adjusted so that the segments 61 are overlapped in multiple layers to distribute the stress during the bending process of the uncoated portion 43 as much as possible and sufficiently ensure the welding strength with the current collector.In another modification, the height of the second portion B 3 may decrease gradually or stepwise similarly to the first embodiment and the second embodiment.In yet another modification, the segment structure of the third portion B 2 may expand to the second portion B 3 (see dotted line). In this case, the second section B 3 can also have a plurality of segments, such as the third section B 2. Preferably, the segment structure of the second portion B 3 may be substantially the same as that of the outermost segment group of the third portion B 2. In this case, the segments included in the second portion B 3 and the third portion B 2 may have substantially the same width, height, and separation distance. In a modified example, the segments of the second portion B 3 may have a width and / or height and / or a separation distance that are greater than that of the third portion B 2.In the third section B 2, the range (groups 1 to 7) in which the heights of the segments 61 increase stepwise based on the winding direction of the electrode 60 may be defined as a variable segment height range, and the last segment group (group 8) may be defined as a uniform height range in which the heights of the segments are uniformly maintained.That is, in the third section B 2, when the heights of the segments 61 increase stepwise from h 1 to h N the range in which the segments 61 having the heights of h 1 to h N-1( N is a height index, a natural number greater than or equal to 2) corresponds to the variable height range, and the range in which the segments 61 having the height of h N are placed corresponds to the uniform height range. The ratio of the variable height range and the uniform height range to the length of the electrode 60 in the winding direction will be described later with reference to specific embodiments.When the electrode 60 is used to fabricate an electrode assembly of a cylindrical battery having a shape factor of 4680, the width (d B1) of the first portion B 1 may be 180 mm to 350 mm. The width of the group 1 may be 35% to 40% of the width of the first portion B 1. The width of the group 2 may be 130% to 150% of the width of the group 1. The width of the group 3 may be 120% to 135% of the width of the group 2. The width of the group 4 may be 85% to 90% of the width of the group 3. The width of the group 5 may be 120% to 130% of the width of the group 4. The width of the group 6 may be 100% to 120% of the width of the group 5. The width of the group 7 may be 90% to 120% of the width of the group 6. The width of the group 8 may be 115% to 130% of the width of the group 7. The width (d B3) of the second portion B 3 may be 180 mm to 350 mm, similar to the width of the first portion B 1.The widths of the groups 1 to 8 do not show a constant increase or decrease pattern because the segment width gradually increases from group 1 to group 8, but the number of segments included in the group is limited to an integer and the thickness of the electrode has a slight deviation in the winding direction. Accordingly, the number of segments in a specific segment group can be reduced. Therefore, the widths of the groups can show an irregular pattern of change from the core to the outer periphery as in the above example.That is, assuming that the width in the winding direction for each of the three segment groups consecutively adjacent to each other in the circumferential direction of the electrode assembly is W 1, W 2, and W 3, respectively, it is possible for the electrode assembly to include a combination of segment groups in which W 3 / W 2 is smaller than W 2 / W 1.In the specific example, groups 4 to 6 correspond to the above case. The width ratio of the group 5 to the group 4 is 120% to 130%, and the width ratio of the group 6 to the group 5 is 100% to 120%, which is less than 120% to 130%.When the uncoated portion 43 of the electrode 60 has a segment structure, the electrode 60 may have a segment skip region 64 in which some of the plurality of segments are regularly or irregularly omitted as shown in FIG. 14 j, according to still another modification.Preferably, the segment skip portion 64 may be plural. In one example, the width of the segment skip region 64 may be constant from the core to the outer periphery. In another example, the width of the segment skip portion 64 from the core to the outer periphery may increase or decrease regularly or irregularly. Preferably, the height of the uncoated portion existing in the segment skip region 64 may correspond to the height of the first portion B 1 and / or the second portion B 3.The number of segments 61 existing between the segment skip area 64 may be at least one. As shown in FIG. 14 j, the electrode 60 may include an uncoated portion in which the number of segments 61 existing between the segment skip portions 64 increases from the core to the outer periphery.Preferably, the width of the segment skip portion 64 may be set such that when the electrode 60 is wound, as shown in FIG. 14 k, the segments located at each winding turn may be disposed within a preset independent range 66 based on the core center C of the electrode assembly 65.In other words, the plurality of segments 61 may be located within a plurality of independent regions 66 based on the core center C when the electrode assembly 65 is viewed in the winding axis direction. The number of the independent areas 66 may be changed to 2, 3, 4, 5, etc.Preferably, the independent portion 66 may be fan-shaped. In this case, the angle between the independent regions 66 may be substantially the same. Additionally, the circumferential angle (δ) of the independent region 66 may be 20 degrees or more, optionally 25 degrees or more, optionally 30 degrees or more, optionally 35 degrees or more, or optionally 40 degrees or more.In a modification, the independent region 66 may have a geometric shape, such as a square, rectangle, quadrilateral, trapezoid, etc.In the present disclosure, the shape of the segment 61 may be modified differently.FIG. 15 ais a plan view showing the structure of an electrode 70 according to the fifth embodiment of the present disclosure.Referring to Fig. 15a, the electrode 70 of the fifth embodiment is substantially the same as the previous embodiment, except that the shape of the segment 61' is different. Therefore, the configuration of the fourth embodiment can be applied equally to the fifth embodiment unless otherwise described.Segment 61' has a geometric figure with substantially equal upper and lower widths. Preferably, segment 61' may have a rectangular shape.Figure 15b is a diagram showing the definitions of width, height and separation distance of the rectangular segment 61'.Referring to FIG. 15 b, the width (D), height (H), and separation distance (P) of the segment 61' may be adjusted to prevent the uncoated portion 43 from being torn off during bending of the uncoated portion 43 and to prevent abnormal deformation of the uncoated portion 43 while sufficiently increasing the number of overlapping layers of the uncoated portion 43 to improve the welding strength with the current collector. The abnormal deformation means that the uncoated portion below the bending point does not maintain a straight state and is irregularly deformed while falling down.The width (D) of the segment 61' is defined as a length between two points at which two straight lines extending from both sides of the segment 61' meet a straight line extending from the bottom 63a of the cut groove 63. The height (H) of the segment 61' is defined as a shortest distance between the top edge of the segment 61' and the straight line extending from the bottom 63a of the cut groove 63. The separation distance (P) of the segment 61' is defined as a length between two points at which the straight line extending from the bottom 63a of the cut groove 63 meets straight lines extending from two sides 63b connected to the bottom 63a. When the side 63 band / or the bottom 63 aare curved, the straight line may be replaced with a tangent extending from the side 63 band / or the bottom 63 aat an intersection where the side 63 band the bottom 63 acomes.Preferably, the conditions for the width (D), the height (H) and the separation distance (P) of the segment 61' are substantially the same as those of the fourth embodiment described above, and therefore will not be described again. However, since the segment 61' has a rectangular shape, the lower inner angle of the segment 61' may be constant as 90 degrees.Similarly to the electrode 60 of the fourth embodiment, the electrode 70 according to the fifth embodiment may also include a segment skip portion 64 in which some of the plurality of segments are regularly or irregularly omitted, as shown in FIG. 15 c.When the electrode 70 having the segment skip portion 64 is wound into an electrode array, the segments may also be located within the plurality of independent portions 66, as shown in FIG. 14 k.As in the fourth embodiment and the fifth embodiment, when the third portion B2 and the second portion B3 have a plurality of segments 61, 61', the shape of each segment 61, 61' can be modified in various ways.Preferably, the segment may be deformed into various shapes while satisfying at least one of the following conditions.Condition 1: The width of the lower portion is larger than the width of the upper portionCondition 2: The width of the lower portion is the same as the width of the upper portionCondition 3: The width is kept uniform from the upper portion to the lower portionCondition 4: The width decreases from the upper portion to the lower portionCondition 5: The width decreases and then increases from the lower portion to the upper portionCondition 6: The width increases and then decreases from the lower portion to the upper portionCondition 7: The width increases from the lower portion to the upper portion and is then kept uniformCondition 8: The width decreases from the lower portion to the upper portion and is then kept uniformCondition 9: The internal angle of one side and the internal angle of the other side of the lower portion are equalHere, the inner angle may be defined as an angle formed by the side portion of the segment with respect to the width direction of the lower portion of the segment. When the side portion is a curve, the internal angle is defined as the angle between the tangent drawn at the lowest end of the curve and the width direction of the lower portion of the segment.Condition 10: The inner angle of one side of the lower portion and the inner angle of the other side are differentCondition 11: The inner angle of one side of the lower portion and the inner angle of the other side of the lower portion have an acute angle, a right angle and an obtuse angle, respectivelyCondition 12: Symmetric in the left and right directions with respect to the winding axis directionCondition 13: Asymmetric in the left and right directions with respect to the winding axis directionCondition 14: The side portion is straightCondition 15: The side portion is curvedCondition 16: The side portion is convex outwardCondition 17: The side portion is convex inwardlyCondition 18: The corner of the upper portion and / or the lower portion has a structure in which straight lines meetCondition 19: The corner of the upper portion and / or the lower portion has a structure in which a straight line and a curve meetCondition 20: The corner of the upper portion and / or the lower portion has a structure in which curves meetCondition 21: The corner of the upper portion and / or the lower portion has a round structureFIG. 16 is a diagram exemplarily showing the shapes of segments according to various modifications of the present disclosure.As shown in the drawing, the segment may have various geometric shapes in which a dotted line connecting the lower portions of both cut grooves serves as a base. The geometric shape has a structure in which at least one straight line, at least one curved line, or a combination thereof are connected. In an example, the segment may have a polygonal shape, a round shape, or various combinations thereof.Specifically, the segment may have a left-right symmetric trapezoidal shape (a); a left-right asymmetric trapezoidal shape (b); a parallelogram shape (c; a triangular shape (l; a pentagonal shape (k; an arc shape (e; or an elliptical shape (f).Since the shape of the segment is not limited to that shown in FIG. 16, it may be converted into other polygonal shapes, other round shapes, or combinations thereof to satisfy at least one of the above-described conditions 1 to 21.In the polygonal shapes a, b, c, k, and l of the segment, the corners of the upper portion and / or the lower portion may have a shape in which straight lines meet or a round shape (see the enlarged view of the corners of the upper portion and / or the lower portion of the shape a).In the polygonal shapes a, b, c, k, and l of the segment and the curved shapes e and f of the segment, the internal angle (θ 1) on one side and the internal angle (θ 2) on the other side of the lower portion may be the same or different, and the internal angle (θ 1) on one side and the internal angle (θ 2) on the other side of the lower portion may be an acute angle, a right angle, and an obtuse angle, respectively. The internal angle is an angle at which the base and the side of a geometric figure meet. If the side is curved, the straight line may be replaced by a tangent extending from the point where the base meets the side.The shape of the side portion of the segment having a polygonal shape may be modified in various ways.In one example, the side portion of segment shape a may be transformed into an outwardly convex curve, such as shape d, or may be transformed into an inwardly curved segment, such as shape g or j.In another example, the side portion of segment shape a may be transformed into a curved straight line that is indented into the segment, such as shape h or i. Although not shown, the side portion of the segment shape a may be converted into an outwardly convexly curved straight line.In the segment shapes d, g, j, h, and i in which the side portion is modified in various ways, the internal angle (θ 1) on one side and the internal angle (θ 2) on the other side of the lower portion may be the same or different, and the internal angle (θ 1) on one side and the internal angle (θ 2) on the other side of the lower portion may be any one of an acute angle, a right angle, and an obtuse angle, respectively.The width of the segment may have different patterns of changes from bottom to top.In one example, the width of the segment may be kept uniform from bottom to top (shape c). In another example, the width of the segment may gradually decrease from bottom to top (shapes a, b, d, e, f, and g). In yet another example, the width of the segment may gradually decrease from bottom to top and then increase (shapes i and j). In yet another example, the width of the segment may gradually increase from bottom to top and then decrease (shape k). In yet another example, the width of the segment may gradually decrease from bottom to top and then be maintained uniform (shape h). Although not shown, the width of the segment may gradually increase from bottom to top and then be maintained uniform.Meanwhile, among the shapes of the segment illustrated in FIG. 16, the polygonal shape having a flat top may be rotated 180 degrees. In one example, when the segment shape a, b, d, or g rotates 180 degrees, the width of the segment may gradually increase from bottom to top. In another example, when the segment shape h is rotated 180 degrees, the width of the segment may be kept uniform from bottom to top and then gradually increase.In the above-described embodiments (modifications), according to another aspect of the present disclosure, it is possible to change the shape of the segment 61, 61' differently according to the range of the third portion B 2. In an example, for a region where stress is concentrated, a round shape (e.g., semi-circle, ellipse, etc.) favorable for stress distribution may be applied, and for a region where stress is relatively low, a polygonal shape (e.g., square, trapezoid, parallelogram, etc.) having a wide range may be applied as far as possible.In another aspect, the plurality of segments may have different shapes individually, in a group unit, or in two or more group units along a direction parallel to the winding direction of the electrode assembly.In the embodiments (modifications), the segment structure of the third portion B 2 may also be applied to the first portion B 1. However, when the segment structure is applied to the first portion B1, a reverse forming phenomenon may occur in which the end of the first portion B1 is curved toward the outer periphery when the segment 61, 61' of the third portion B2 is curved according to the radius of curvature of the core. Therefore, even if no segment structure is present in the first portion B1, or even if the segment structure is applied, it is desirable to set the width and / or the height and / or the separation distance of the segment 61, 61' as small as possible to a level at which reverse shaping does not occur in consideration of the radius of curvature of the core.According to still another aspect of the present disclosure, after the electrode 60, 70 is wound in the electrode assembly, the segments exposed at the upper portion and the lower portion of the electrode assembly may be overlapped in multiple layers along the radial direction of the electrode assembly to form the bending surface areas.FIG. 17 ais a schematic diagram showing a cross section of the bending surface area F formed by bending the segments 61 toward the core C of the electrode assembly 80. In FIG. 17 a, the cross section of the bending surface area F is shown only on the left side with respect to the winding axis of the electrode assembly 80. The bending surface area F may be formed at both the upper portion and the lower portion of the electrode assembly 80. FIG. 17 bis a perspective plan view schematically showing the electrode assembly 80 in which the bending surface area F is formed.Referring to FIGS. 17 aand 17 b, the bending surface area F has a structure in which the segments 61 are overlapped in multiple layers in the winding axis direction. The overlapping direction is the winding axis direction Y. The region 1 is a segment skip region (first portion B 1) without a segment, and the regions 2 and 3 are regions where winding turns including the segments 61 are located. The region 2 is a height-variable region in which the heights of the segments 61 vary, and the region 3 is a height uniform region in which the heights of the segments are uniformly maintained up to the outer periphery of the electrode assembly. As will be described later, the lengths of the region 2 and the region 3 in the radial direction may be variable. Meanwhile, the uncoated portion (second portion B 3) included in at least one winding turn including an outermost winding turn may not have a segment structure. In this case, the second portion B 3 in the region 3 may be excluded.In the region 2, the heights of the segments 61 can be changed stepwise from the minimum height h 1(= h min) to the maximum height h N(= h max) in the radius r 1 to the radius r N- of the electrode arrangement 80. The height-variable ranges in which the heights of the segments 61 vary are r 1 to r N. From the radius r N to the radius R of the electrode assembly 80, the heights of the segments 61 are maintained uniformly at h N. Uniform heights mean that the deviation of the heights is within 5%.At each radius position in the area 2 and the area 3, the stacking number of the segments 61 varies depending on the radius position. In addition, the stacking number of the segments 61 may vary depending on the width of the region 2, the minimum height (h 1) and the maximum height (h N) of the segments in the height-variable region of the segments 61, and the height change amount (Δh) of the segments 61. The stacking number of the segments 61 is the number of segments that meet an imaginary line when the imaginary line is drawn from an arbitrary radius position of the electrode assembly 80 in the winding axis direction.Preferably, the stacking number of the segments 61 at each position of the bending surface area F can be optimized according to the required welding strength of the current collector by adjusting the height, the width, and the separation distance of the segments 61 according to the radius of the winding turn including the segment 61.First, in the height variable range (2) of the segments 61, when the minimum height (h 1) of the segments is equal, it is described by specific embodiments how the stacking number of the segments 61 varies along the radial direction of the bending surface area F according to the change in the maximum height (h N) of the segments 61.The electrode assemblies of Embodiments 1-1 to 1-7 are manufactured. The electrode assemblies of the embodiments have a radius of 22 mm and a core diameter of 4 mm. The positive electrode and the negative electrode included in the electrode assembly have the electrode structure shown in FIG. 14 d. That is, the segment has a trapezoidal shape. The second positive electrode and negative electrode portion B 3 does not include a segment. The length of the second portion B 3 is 3% to 4% of the total length of the electrode. The positive electrode, the negative electrode, and the separator are wound by the method described in FIG. 2. The winding turns are between 48 turns and 56 turns, but the winding turns of the embodiments are 51 turns. The thicknesses of the positive electrode, the negative electrode, and the separator are 149 μm, 193 μm, and 13 μm, respectively. The thickness of the positive electrode and the negative electrode is the thickness including the thickness of the active material layer. The thicknesses of the positive electrode current collector and the negative electrode current collector are 15 μm and 10 μm, respectively. The lengths of the positive and negative electrodes in the winding direction are 3948 mm and 4045 mm, respectively.In each embodiment, the minimum height of the segments 61 is set to 3 mm, so that the height-variable region (2) of the segments 61 starts with a radius of 5 mm. In addition, in each embodiment, the heights of the segments 61 are increased by 1 mm per 1 mm radius increase, and the maximum height of the segments 61 is changed differently from 4 mm to 10 mm.Specifically, in Embodiment 1-1, the height-variable range (2) of the segments 61 is 5 mm to 6 mm, and the heights of the segments 61 are variable from the radius 3 mm to 4 mm. In Embodiment 1-2, the height-variable range (2) of the segments 61 is 5 mm to 7 mm, and the heights of the segments 61 are variable from 3 mm to 5 mm. In Embodiment 1-3, the height variable range (2) of the segments 61 is 5 mm to 8 mm, and the heights of the segments 61 are variable from 3 mm to 6 mm. In Embodiment 1-4, the height-variable range (2) of the segments 61 is 5 mm to 9 mm, and the heights of the segments 61 are variable from 3 mm to 7 mm. In Embodiment 1-5, the height variable range (2) of the segments 61 is 5 mm to 10 mm, and the heights of the segments 61 are variable from 3 mm to 8 mm. In Embodiment 1-6, the height variable range (2) of the segments 61 is 5 mm to 11 mm, and the heights of the segments 61 are variable from 3 mm to 9 mm. In Embodiment 1-7, the height variable range (2) of the segments 61 is 5 mm to 12 mm, and the heights of the segments 61 are variable from 3 mm to 10 mm. In Embodiment 1-1 to 1-7, the heights of the segments 61 are uniform from the radius corresponding to the upper limit of the height variable region (2) to the outer periphery. In one example, in Embodiment 1-7, the heights of the segments 61 are uniform at 10 mm from the radius 12 mm to 22 mm. Meanwhile, in the electrode assembly of the comparative example, the heights of the segments 61 are maintained at a single height of 3 mm from the radius of 5 mm to the radius of 22 mm.FIG. 17 care graphs showing the results of counting the number of stacks of segments along the radial direction in the positive electrode bending surface area F formed at the upper portion of the electrode assemblies according to Embodiments 1-1 to 1-7 and the comparative example. The negative electrode bending surface area also exhibits substantially the same results. The horizontal axis of the graph is the radius based on the center of the core, and the vertical axis of the graph is the stacking number of segments counted at each radius point, which is also applied in the same manner to FIGS. 17 dand 17 ethat will be explained later.Referring to FIG. 17 c, the stack number uniformity range b 1 of the segments is usually shown in Embodiments 1- 1 to 1- 7 and Comparative Example 1. The stack number uniformity region b 1 is a radial region of a flattened area in each graph. The length of the stack number uniformity region b1 increases as the maximum height of the segments decreases, and the stack number uniformity region b1' of the comparative example is longest. Meanwhile, the stack number of segments increases as the maximum height (h N) of the segments increases. That is, as the maximum height (h N) of the segments increases so that the width of the height-variable region (2) of the segments increases, the stack number of segments increases, while the width of the stack number uniform region b 1 decreases. On the outside of the stack number uniform area b 1, the stack number decreasing area b 2 in which the stack number of segments decreases as the radius increases appears. The stack number decreasing region b 2 is a radial region in which the stack number of segments decreases as the radius of the electrode assembly increases. The stack number uniform area b 1 and the stack number decrease area b 2 are adjacent in the radial direction and complementary to each other. That is, as the length of one region increases, the length of the other region decreases. In addition, in the stack number decreasing region b 2, the stack number decreases in proportion to the distance away from the stack number uniform region b 1.From the viewpoint of the stacking number of the segments, in Embodiments 1-1 to 1-7, the stacking number of the segments is 10 or more in the uniform range b 1. A range in which the stack number of segments is 10 or more can be set as a desired welding target range. The welding target area is an area to which at least a part of the current collector can be welded.In Embodiments 1-1 to 1-7, the stack number uniformity region b1 starts from the radius point at which the height variable region (2) of the segments starts. That is, the height variable region (2) starts with the radius of 5 mm and extends to the outer periphery.In Embodiments 1-1 to 1-7 and Comparative Example 1, the following Table 4 shows the results of calculating a ratio of the length of the segment skip portion (c, 1 in FIG. 17 a) to the radius (b-a) of the electrode assembly except for the core, a ratio (e / f) of the length of the stack number uniform area b 1 to the length (f) from the radius point (5 mm) at which the stack number uniform area starts to the outermost point (22 mm) of the electrode assembly, a ratio (d / f) of the length of the height-variable area (d) of the segment to the length (f) from the radius point (5 mm) at which the stack number uniform area starts, to the outermost point (22 mm) of the electrode array, a ratio (h) of the length of the electrode region corresponding to the segment skip region (first portion B 1) to the entire length of the electrode, a ratio (i) of the length of the electrode region corresponding to the height-variable region to the entire length of the electrode, and a ratio (i) of the length of the electrode region corresponding to the height-uniform region to the entire length of the electrode, and the like.Except that the negative electrode shows a difference of 0.1% to 1.2% for the parameter h, the other parameters are substantially the same as the positive electrode. The sum of the proportions h, i and j differs slightly from 100%. The reason is that there is a segment-less region in the second portion B 3 corresponding to the outer peripheral side uncoated portion of the electrode. For example, in Embodiment 1-1, no segment corresponding to about 4% of the entire length of the electrode exists in the second portion B3. In Table 4, a to f are parameters based on the length in the radial direction, and h, i, and j are parameters based on the length in the longitudinal direction of the electrode before the electrode is wound into an electrode assembly. In addition, the parameters corresponding to the ratio (%) are values rounded at a decimal point. These items are substantially the same in Tables 5 and 6 which will be explained later.Regarding Embodiments 1-1 to 1-7 of Table 4, the stacking number of segments is 11 to 27, and the ratio (d / f) of the height-variable region (d) to the radial region f containing segments is 6% to 41%. In addition, the ratio (e / f) of the stack number uniformity region (e) to the radial region f including segments is 47% to 82%. In addition, the ratio (c / (b-a)) of the segment skip portion (c, 1 in FIG. 17 a) to the radius (b-a) of the electrode assembly except for the core is 15%. In addition, the ratio of the length of the electrode surface corresponding to the segment skip region (first portion B 1) to the entire length of the electrode is 6%, the ratio of the length of the electrode surface corresponding to the height-variable region to the entire length of the electrode is 3% to 32%, and the ratio of the length of the electrode surface corresponding to the height uniformity region to the entire length of the electrode is 59% to 87%.The stack number (g) of the stack number uniform area is 10 or more in all of Embodiments 1-1 to 1-7. The stack number uniformity range (e) decreases as the height variable range (d) of the segments increases, but the stack number (g) of the segments increases in the stack number uniformity range (e). Preferably, the stack number uniform area (e) in which the stack number (g) of segments is 10 or more may be set as a welding target area.In cylindrical batteries having shape factors of 1865, 2170, the radius of the electrode assembly is about 9 mm to 10 mm. Therefore, for a conventional cylindrical battery, as in Embodiments 1-1 to 1-7, the length of the segment portion (f) in the radial direction cannot be secured at the level of 17 mm, and the length of the stack number uniformity portion (e) cannot be secured at the level of 8 mm to 14 mm. This is because in a conventional cylindrical battery, when the radius of the core is made 2 mm, which is the same as in Embodiments 1-1 to 1-7, the radial range in which segments can be arranged is substantially only 7 mm to 8 mm. Moreover, in the conventional cylindrical battery, the length of the electrode in the winding direction is about 600 mm to 980 mm. This short length of the electrode is only about 15% to 24% of the length of the electrode (positive electrode 3948 mm, negative electrode 4045 mm) used in Embodiments 1-1 to 1-7. Therefore, the numerical ranges for the parameters h, i, and j cannot be easily derived from design specifications of the conventional cylindrical battery.Next, when the maximum height (h N) of the segments in the height variable region (2 in FIG. 17a) of the segments is the same, it will be explained by specific embodiments how the stacking number of the segments varies along the radial direction of the bending surface region F according to the change in the minimum height (h 1) of the segments.The electrode assemblies of Embodiments 2-1 to 2-5 have a radius of 22 mm and a core diameter C of 4 mm. In the height variable region (2 in Fig. 17a) of the segments 61, the minimum height (h 1) is 4 mm and the maximum height (h-N) varies from 6 mm to 10 mm in steps of 1 mm. Therefore, in the electrode assemblies of Embodiments 2-1 to 2-5, the variable height region (2 in FIG. 17a) of the segments has a width of 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm, respectively, and the segment skip region (1 in FIG. 17a) is a radial region having a radius of 2 mm to 6 mm.The electrode assemblies of Embodiments 3-1 to 3-4 have a radius of 22 mm and a core diameter C of 4 mm. In the height-variable region (2 in Figure 17a) of the segments 61, the minimum height (h 1) is equal to 5 mm and the maximum height (h N) varies from 7 mm to 10 mm in steps of 1 mm. Therefore, in the electrode assemblies of Embodiments 3-1 to 3-4, the variable height region (2 in FIG. 17a) of the segments has a width of 2 mm, 3 mm, 4 mm, and 5 mm, respectively, and the segment skip region (1 in FIG. 17a) is a radial region having a radius of 2 mm to 7 mm.The electrode assemblies of Embodiments 4-1 to 4-3 have a radius of 22 mm and a core diameter C of 4 mm. In the height-variable region (2 in Figure 17a) of the segments 61, the minimum height (h 1) is equal to 6 mm and the maximum height (h N) varies from 8 mm to 10 mm in steps of 1 mm. Therefore, in the electrode assemblies of Embodiments 4-1 to 4-3, the width of the height variable region (2 in FIG. 17a) of the segments is 2 mm, 3 mm, and 4 mm, respectively, and the segment skip region (1 in FIG. 17a) is a radial region having a radius of 2 mm to 8 mm.The electrode assemblies of Embodiments 5-1 to 5-2 have a radius of 22 mm and a core diameter C of 4 mm. In the height variable region (2 in Fig. 17a) of the segments 61, the minimum height (h 1) is equal to 7 mm and the maximum height (h N) varies from 9 mm to 10 mm in steps of 1 mm. Therefore, in the electrode assemblies of Embodiments 5-1 to 5-2, the width of the height variable region (2 in FIG. 17a) of the segments is 2 mm and 3 mm, respectively, and the segment skip region (1 in FIG. 17a) is a radial region having a radius of 2 mm to 9 mm.FIG. 17 dare graphs showing the results of counting the number of stacks of segments along the radial direction in the positive electrode bending surface area F formed at the upper portion of the electrode assemblies according to Embodiments 2- 1 to 2- 5, Embodiments 3- 1 to 3- 4, Embodiments 4- 1 to 4- 3, and Embodiments 5- 1 to 5- 2. The negative electrode bending surface area also exhibits substantially the same results.In FIG. 17 d, the graph (a) shows the result of counting the number of stacks of segments along the radial direction in the bending surface area F for Embodiments 2- 1 to 2- 5, the graph (b) is for Embodiments 3- 1 to 3- 4, the graph (c) is for Embodiments 4- 1 to 4- 3, and the graph (d) is for Embodiments 5- 1 to 5- 2.Referring to FIG. 17 d, the stack number uniformity region b 1 of the segments appears common in all embodiments. The stack number uniform area b 1 is a radial area of the flat surface in the graph. The length of the stack number uniformity region b 1 increases as the maximum height (h N) of the segments decreases when the minimum height (h 1) of the segments is equal. Also, the length of the stack number uniform area b 1 increases as the minimum height (h 1) of the segments decreases when the maximum height (h N) of the segments is equal. Meanwhile, in the stack number uniform area b 1, the stack number of segments increases as the maximum height (h N) of the segments increases. Even in the embodiments, the stack number decrease region b 2 appears near the stack number uniformity region b 1.In all embodiments, the stack number of segments in the stack number uniform area b 1 is 10 or more. Preferably, a range in which the stack number of segments is 10 or more may be set as a desired welding target range.In the embodiments, the stack number uniformity region b 1 starts from the radius point at which the height variable region ( 2 in FIG. 17 a) of the segments starts. In embodiments 2-1 to 2-5, the variable height range (2 in Figure 17a) of the segments starts from 6 mm and extends to the outer periphery. In embodiments 3-1 to 3-4, the variable height range (2 in Figure 17a) of the segments starts from 7 mm and extends to the outer periphery. In embodiments 4-3 to 4-3, the variable height range (2 in Figure 17a) of the segments starts from 8 mm and extends to the outer periphery. In embodiments 5-1 to 5-2, the variable height range (2 in Figure 17a) of the segments starts from 9 mm and extends to the outer periphery.Table 5 below shows the results of calculating various parameters for Embodiments 2-1 to 2-5, Embodiments 3-1 to 3-4, Embodiments 4-1 to 4-3, and Embodiments 5-1 to 5-2, including a ratio (e / f) of the length of the stack number uniform area to the length from the radius point (6 mm, 7 mm, 8 mm, 9 mm) at which the stack number uniform area starts to the outermost point (22 mm) of the electrode array, a ratio (d / f) of the length of the height-variable area (2) of the segments to the length from the radius point (6 mm, 7 mm, 8 mm, 9 mm) at which the stack number uniform area starts to the outermost point (22 mm) of the electrode array, and the like.Referring to Embodiments 2-5, 3-4, 4-3, and 5-2 of Table 5 together with Figs. 17a and 17d, the maximum height (h N) of the segments in the height-variable region (2) of the segments is equal to 10 mm, but the minimum height (h 1) of the segments increases to 4 mm, 5 mm, 6 mm, and 7 mm by 1 mm, and the length of the height-variable region (2) decreases to 6 mm, 5 mm, 4 mm, and 3 mm by 1 mm. In the four embodiments, the ratio (e / f) of the stack number uniform area is the largest in the embodiments 2-5 at 69% and the smallest in the embodiment 5-2 at 38%, and the stack numbers of the stack number uniform areas are all the same.From the results shown in Table 5, when the maximum height (h N) of the segments is equal, it can be understood that as the width of the height-variable region (2) of the segment increases, since the minimum height (h 1) of the segments decreases, the width of the stack number uniform region also increases proportionally. The reason is that as the minimum length (h 1) of the segments is smaller, the radius point at which the segment starts is closer to the core and thus the area in which the segments are stacked expands toward the core.When Table 5 is considered, it can be determined that the stack number of the segments is 16 to 26, the ratio (d / f) of the height variable range (2) of the segments is 13% to 38%, and the ratio (e / f) of the stack number uniform range is 31% to 69%. In addition, the ratio (c / (b-a)) of the segment skip portion (1) to the radius (b-a) of the electrode assembly except for the core is 20% to 35%. In addition, the ratio of the length of the electrode surface corresponding to the segment skip portion (1) to the entire length of the electrode is 10% to 20%, the ratio of the length of the electrode surface corresponding to the height variable portion (2) to the entire length of the electrode is 6% to 25%, and the ratio of the length of the electrode surface corresponding to the height uniformity portion (3) to the entire length of the electrode is 62% to 81%.In cylindrical batteries having form factors of 1865, 2170, the electrode array has a radius of about 9 mm to 10 mm. Therefore, unlike the embodiments, it is not possible to secure the length of the segment portion (f) in the radial direction at the level of 13 mm to 16 mm, and it is not possible to secure the length of the stack number uniform area (e) in which the stack number of the segments is 10 or more at the level of 5 mm to 11 mm while securing the length of the segment skip portion (c, 1) at the level of about 4 mm to 7 mm. This is because in the conventional cylindrical battery, when the radius of the core is made 2 mm, which is the same as in the embodiments, the radial range in which segments can be arranged is substantially only 7 mm to 8 mm. Moreover, in the conventional cylindrical battery, the length of the electrode in the winding direction is about 600 mm to 980 mm. This short length of the electrode is only about 15% to 24% of the length of the electrode (positive electrode 3948 mm, negative electrode 4045 mm) in the embodiments. Therefore, the numerical ranges for the parameters h, i, and j cannot be easily derived from design specifications of the conventional cylindrical batteries.Next, when the minimum height (h 1) and the maximum height (h N) of the segments in the height variable region (2) of the segments are the same, it will be explained by specific embodiments how the stacking number of the segments changes according to the diameter of the core C of the electrode assembly along the radial direction of the bending surface region F.The electrode assemblies of Embodiments 6-1 to 6-6 have a radius of 22 mm, and the radius of the core C is 4 mm. In the height-variable region (2) of the segments 61, the minimum height (h 1) of the segments is equal to 3 mm and the maximum height (h N) of the segments varies from 5 mm to 10 mm in steps of 1 mm. Therefore, in the electrode assemblies of Embodiments 6-1 to 6-6, the width of the height-variable region (2) of the segments is 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm, respectively, and the segment skip region (1) is a radial region having a radius of 4 mm to 7 mm.The electrode assemblies of Embodiments 7-1 to 7-6 have a radius of 22 mm, and the radius of the core C is 2 mm. In the height-variable region (2) of the segments 61, the minimum height (h 1) of the segments is equal to 3 mm and the maximum height (h N) of the segments varies from 5 mm to 10 mm in steps of 1 mm. Therefore, in the electrode assemblies of Embodiments 7-1 to 7-6, the height-variable region (2) of the segments has a width of 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm, respectively, and the segment skip region (1) is all equal to a radial region having a radius of 2 mm to 5 mm.FIG. 17 eare graphs showing the results of counting the number of stacks of segments along the radial direction in the positive electrode bending surface area F formed at the upper portion of the electrode assembly according to Embodiments 6- 1 to 6- 6 and Embodiments 7- 1 to 7- 6. Substantially the same results appear in the negative electrode bending surface area.In FIG. 17 e, the graph (a) shows the result of counting the number of stacks of segments along the radial direction in the bending surface area F for the embodiments 6- 1 to 6- 6, and the graph (b) is for the embodiments 7- 1 to 7- 6.Referring to FIG. 17 e, the stack number uniformity region b 1 of the segments appears common in all embodiments. The stack number uniform area b 1 is a radial area of the flat surface in the graph. The length of the stack number uniformity region b 1 in the radial direction increases as the maximum height (h N) of the segments decreases when the minimum height (h 1) of the segments is equal. Meanwhile, in the stack number uniform area b 1, the stack number of segments increases as the maximum height (h N) of the segments increases. In the embodiments, the stack number decrease region b 2 near the stack number uniformity region b 1 is identified.In all embodiments, the stack number of the segments in the stack number uniform area b 1 is 10 or more. Preferably, a range in which the stack number of segments is 10 or more may be set as a desired welding target range.In the embodiments, the stack number uniformity region b 1 starts from the radius point at which the height variable region ( 2) of the segments starts. In Embodiments 6-1 to 6-6, the radius at which the height-variable region (2) of the segments starts is 7 mm, and in Embodiments 7-1 to 7-6, the radius at which the height-variable region (2) of the segments starts is 5 mm.Table 6 below shows the results of calculating various parameters for Embodiments 6-1 to 6-6 and Embodiments 7-1 to 7-6, including a ratio (e / f) of the length of the stack number uniform area to the length from the radius point (7 mm, 5 mm) at which the stack number uniform area starts to the outermost point (22 mm) of the electrode array, a ratio (d / f) of the length of the height variable area (2) of the segments to the length from the radius point (7 mm, 5 mm) at which the stack number uniform area starts to the outermost point (22 mm) of the electrode array, and the like.Referring to Fig. 17a and embodiments 6-6 and 7-6 of Table 6, the minimum height (h 1) and the maximum height (h N) of the segments in the height-variable region (2) of the segments are equal to 3 mm and 10 mm, respectively. However, in Embodiment 6-6, the radius of the core is larger by 2 mm than in Embodiment 7-6. Therefore, in Embodiment 6-6, the stack number uniform area (e) and the segment area (f) are smaller by 2 mm than in Embodiment 7-6, and the stack number of the segments is equal in the stack number uniform area. This result arises from the difference in the radius of the core. From the results shown in Table 6, when the width of the height-variable region (2) of the segments is equal, it can be understood that, as the radius (a) of the core is smaller, the ratio (d / f) of the height-variable region (2) decreases but the ratio (e / f) of the stack number uniformity region increases.When Table 6 is seen, it can be determined that the stack number of the segments is 13 to 26, the ratio (d / f) of the height variable region (2) of the segments is 12% to 47%, and the ratio (e / f) of the length of the stack number uniform region is 40% to 76%. In addition, the ratio (c / (b-a)) of the segment skip portion (1) to the radius (b-a) of the electrode assembly except for the core is 15% to 17%. In addition, the ratio of the length of the electrode surface corresponding to the segment skip portion (1) to the entire length of the electrode is 6%, the ratio of the length of the electrode surface corresponding to the height variable portion (2) to the entire length of the electrode is 7% to 32%, and the ratio of the length of the electrode surface corresponding to the height uniformity portion (3) to the entire length of the electrode is 59% to 83%.For cylindrical batteries having form factors of 1865, 2170, the radius of the electrode assembly is about 9 mm to 10 mm. Therefore, unlike the embodiments, the length of the segment portion (f) in the radial direction is not secured at the level of 15 mm to 17 mm, and at the same time, the length of the stack number uniform portion (e) in which the stack number of the segments is 10 or more cannot be secured at the level of 6 mm to 13 mm while the length of the segment skip portion (1) is secured at the level of about 3 mm. This is because in the conventional cylindrical battery, when the radius of the core is made 2 mm to 4 mm, which is the same as in the embodiments, the radial range in which segments can be arranged is substantially only 5 mm to 8 mm. Moreover, in the conventional cylindrical battery, the length of the electrode in the winding direction is about 600 mm to 980 mm. This short length of the electrode is only about 15% to 24% of the length of the electrode (positive electrode 3948 mm, negative electrode 4045 mm) in the embodiments. Therefore, the numerical ranges for the parameters h, i, and j cannot be easily derived from design specifications of the conventional cylindrical batteries.Considering the data in Tables 4 to 6 comprehensively, the stack number of segments in the stack number uniform range of the segments 11 to 26 may be. In addition, the ratio (d / f) of the variable height range (2) of the segments may be 6% to 47%. In addition, the ratio (e / f) of the stack number uniformity range may be 31% to 82%. In addition, the ratio (c / (b-a)) of the length of the segment skip portion (1) to the radius of the electrode assembly except for the core may be 15% to 35%. In addition, the ratio of the length of the electrode surface corresponding to the segment skip portion (1) to the total length (length in the winding direction) of the electrode may be 6% to 20%. In addition, the ratio of the length of the electrode surface corresponding to the height-variable region (2) of the segments to the total length of the electrode may be 3% to 32%. In addition, the ratio of the length of the electrode surface corresponding to the height uniformity region ( 3) of the segments to the total length of the electrode may be 59% to 87%.Meanwhile, the parameters described in Tables 4 to 6 are varied according to design factors including the radius (a) of the core; the radius of the electrode assembly B; the minimum height (h 1) and the maximum height (h N) in the height-variable range (2) of the segments; the height change amount (Δh) of the segments per 1 mm step of the radius; the thickness of the positive electrode, the negative electrode and the separator; and the like.Therefore, in the stack number uniformity range of the segments, the segment stack number can be extended to 10 to 35. The ratio (d / f) of the height variable region (2) of the segments can be extended to 1% to 50%. In addition, the ratio (e / f) of the stack number uniformity range may be extended to 30% to 85%. In addition, the ratio (c / (b-a)) of the length of the segment skip portion (1) to the radius of the electrode assembly except for the core may be extended to 10% to 40%. In addition, the ratio of the length of the electrode surface corresponding to the segment skip portion (1) to the total length (length in the winding direction) of the electrode may be extended to 1% to 30%. In addition, the ratio of the length of the electrode surface corresponding to the height variable region (2) of the segments to the total length of the electrode can be extended to 1% to 40%. In addition, the ratio of the length of the electrode surface corresponding to the height uniform area (3) of the segments to the total length of the electrode can be extended to 50% to 90%. In the embodiments, the height index N of the maximum height (h N) of the segments included in the height variable region (2) and the height uniformity region (3) is 2 to 8, for example, considering Table 4, the height index N for the embodiments 1-1 and 1-7 is 2 and 8, respectively. When the radial length of the height variable region ( 2) is fixed, the height index N increases accordingly, or vice versa, as the height change amount (Δh) of the segment decreases. Preferably, the height index N can be further extended to 2 to 20, optionally 2 to 30.In the bending surface area F formed at the upper portion and the lower portion of the electrode assembly, the stack number uniform area can be used as the welding target area of the current collector.Preferably, the welding area of the current collector overlaps the stack number uniformity area by at least 50% in the radial direction of the electrode assembly, and a higher overlap ratio is more preferred.Preferably, the resting surface of the welding portion of the current collector that does not overlap with the stack number uniform portion may overlap with the stack number decreasing portion adjacent to the stack number uniform portion in the radial direction.More preferably, the resting area of the welding region of the current collector that does not overlap with the stack number uniform region may overlap with the area of the stack number decreasing region in which the segment stack number is 10 or more.When the current collector is welded to the region where the segment stack number is 10 or more, it is desirable in view of the welding strength and the prevention of damage to the separator or the active material layer during welding. In particular, it is useful when the current collector is welded using a high power laser having high transmission characteristics.When the stack number uniform area in which 10 or more of the segments are stacked and the current collector are welded with a laser, even if the power of the laser is increased to improve the welding quality, the stack number uniform area absorbs most of the laser energy to form a weld bead, so that it is possible to prevent the separator and the active material layer under the bending surface area F from being damaged by the laser.In addition, since the segment stack number is 10 or more in the range where the laser is irradiated, weld beads having a sufficient volume and a sufficient thickness are formed. Therefore, sufficient welding strength can be secured and the resistance of the welding interface can be reduced to a level suitable for quick charging.In welding the current collector, the power of the laser can be determined by the desired welding strength between the bending surface area F and the current collector. The welding strength increases in proportion to the stacking number of segments. This is because the volume of the weld beads formed by the laser increases as the stack number increases. The weld beads are formed when the material of the current collector and the material of the segment are fused together. Therefore, when the volume of the weld bead is large, the current collector and the bending surface area are more strongly coupled, and the contact resistance of the welding interface is reduced.Preferably, the welding strength may be 2 kgf / cm 2 or more, more preferably 4 kgf / cm 2 or more. The maximum weld strength may vary depending on the performance of the laser welders. In addition, the welding strength may preferably be set to 8 kgf / cm 2 or less, more preferably 6 kgf / cm 2 or less. However, the present disclosure is not limited thereto.When the welding strength satisfies the above numerical range, even if a strong vibration is applied to the electrode assembly along the winding axis direction and / or the radial direction, the characteristics of the welding interface do not deteriorate, and the resistance of the welding interface can be reduced because the volume of the weld beads is sufficient.The power of the laser to satisfy the welding strength condition differs depending on the laser devices and can be set suitably in the range of 250 W to 320 W or in the range of 40% to 100% of the maximum laser power supplied from the devices.The welding strength may be defined as a tensile force (kgf / cm 2) per unit area of the current collector when the current collector starts to separate from the bending surface area F. In particular, after the current collector is fully welded, a pulling force may be applied to the current collector while the magnitude of the pulling force is gradually increased. When the pulling force exceeds a threshold, the segment begins to disengage from the welding interface. At this time, the value obtained by dividing the tensile force applied to the current collector by the area of the current collector corresponds to the welding strength.In the bending surface area F, the segments are stacked in multiple layers, and according to the above embodiments, the stacking number of segments may increase to at least 10 to at most 35.The thickness of the positive electrode current collector (foil) constituting the uncoated portion 43 is 10 m to 25 m, and the thickness of the negative electrode current collector (foil) constituting the uncoated portion 43 may be 5 m to 20 m. Therefore, the positive electrode bending surface area F may include an area in which the total stack thickness of the segments is 100 m to 875 m. In addition, the negative electrode bending surface area F may include an area in which the total layer thickness of the segments is 50 m to 700 m.FIG. 17 fis a top plan view of the electrode assembly showing the uniform stack number range b 1 and the decreasing stack number range b 2 in the bending surface range F of the segments 61, 61' according to an embodiment of the present disclosure.Referring to FIG. 17 f, the area between two circles indicated by the thick solid line corresponds to the bending area F of the segments, and the area between two circles indicated by the dot-and-dash line corresponds to the uniform stack number area b 1 in which the stack number of the segments is 10 or more, and the outer surface of the uniform stack number area b 1 corresponds to the decreasing stack number area b 2.In one example, when the current collector (P c) is welded to the bending surface region F, a welding pattern (W p) is generated on the surface of the current collector (P c). The welding pattern (W p) may comprise an array of line patterns or dot patterns. The welding pattern (W p) corresponds to the welding range and may overlap by 50% or more with the uniform stack number range b 1 of the segments along the radial direction. Therefore, a part of the welding pattern (W p) may be included in the uniform stack number range b 1, and the rest of the welding pattern (W p) may be included in the decreasing stack number range b 2 outside the uniform stack number range b 1. Of course, the entire welding pattern (W p) may overlap with the uniform stack number range b 1 to maximize the welding strength and reduce the resistance of the welding range.The area of the bending area F may be defined as the sum of the area of the uniform stack number area b 1 and the area of the decreasing stack number area b 2 of the segment. Since the ratio (e / f) of the uniform stack number range b 1 is 30% to 85%, preferably 31% to 82%, the ratio of the area of the uniform stack number range b 1 to the area of the bending area range F may be 9% (30 2 / 1002) to 72% (852 / 1002), preferably 10% (31 2 / 1002) to 67% (82 2 / 1002).Preferably, the edge of the portion where the current collector (P c) contacts the bending surface area F may cover the end of the segment 61, 61' bent toward the core C in the last winding turn of the uniform height area (3). In this case, since the welding pattern (W p) is formed in a state where the segments 61, 61' are pressed by the current collector (P c) the current collector (P c) and the bending surface area F are strongly coupled. As a result, since the segments 61, 61' stacked in the winding axis direction come into close contact with each other, the resistance at the welding interface can be reduced and lifting of the segments 61, 61' can be prevented.Meanwhile, the bending direction of the segments may be opposite to that described above. That is, the segments may be bent from the core toward the outer periphery. In this case, the pattern in which the heights of the segments change along the winding direction (X-axis direction) may be opposite to that of the above-described embodiments (modifications). For example, the heights of the segments may gradually decrease from the core toward the outer periphery. Also, the structure applied to the first portion B 1 and the structure applied to the second portion B 3 may be switched with each other. Preferably, the height change pattern may be configured such that the heights of the segments gradually decrease from the core toward the outer periphery, but when the segment closest to the outer periphery of the electrode assembly is bent toward the outer periphery, the end of the segment does not protrude from the outer periphery of the electrode assembly.The electrode structure of the above embodiments (modifications) may be applied to at least one of the first electrode and the second electrode having different polarities included in the jelly roll type electrode assembly or another electrode assembly known in the art. In addition, when the electrode structure of the above embodiments (modifications) is applied to any one of the first electrode and the second electrode, the conventional electrode structure may be applied to the other. In addition, the electrode structures applied to the first electrode and the second electrode may not be identical but may be different from each other.For example, when the first electrode and the second electrode are a positive electrode and a negative electrode, respectively, any of the above embodiments (modifications) may be applied to the first electrode, and the conventional electrode structure (see FIG. 1 ) may be applied to the second electrode.As another example, when the first electrode and the second electrode are a positive electrode and a negative electrode, respectively, any of the above embodiments (modifications) may be selectively applied to the first electrode, and any of the above embodiments (modifications) may be selectively applied to the second electrode.Hereinafter, the structure of the electrode assembly according to an embodiment of the present disclosure will be described in detail.FIG. 18 is a cross-sectional view of a jelly roll type electrode assembly 80 in which the electrode 40 according to the first embodiment is applied to a first electrode (positive electrode) and a second electrode (negative electrode) along the Y-axis direction (winding axis direction).The electrode assembly 80 may be manufactured by the winding method described with reference to FIG. 2. For convenience of description, the above structure of the first uncoated portion 43 aand the second uncoated portion 43 bextending to the outside of the separator is shown in detail, and the winding structure of the first electrode, the second electrode, and the separator is not illustrated. The first uncoated portion 43 aprotruding upward extends from the first electrode, and the second uncoated portion 43 bprotruding downward extends from the second electrode.A pattern in which the heights of the first and second uncoated portions 43 a, 43 bchange is schematically shown. That is, the height of the uncoated portion may vary irregularly depending on the position at which the portion is cut. For example, when the side of the trapezoidal segment 61, 61' or the cut groove 63 is cut, the height of the uncoated portion in the cross section is lower than the height (H) of the segment 61, 61'. Accordingly, it should be appreciated that the height of the uncoated portion shown in the cross-sectional drawings of the electrode assembly corresponds to the average of the heights (H in FIGS. 14 band 15 b) of the uncoated portions included in each winding turn.Referring to FIG. 18, the first uncoated portion 43 aincludes a first portion B 1 adjacent to the core of the electrode assembly 80, a second portion B 3 adjacent to the outer circumferential surface of the electrode assembly 80, and a third portion B 2 disposed between the first portion B 1 and the second portion B 3.The height (length in the Y-axis direction) of the second portion B 3 is relatively smaller than the height of the third portion B 2. Therefore, while pressing the bead portion of the battery case in the vicinity of the second portion B 3, it is possible to prevent a phenomenon in which an internal short circuit occurs when the bead portion and the second portion B 3 contact each other.The second uncoated portion 43 bhas the same structure as the first uncoated portion 43 a. In a modification, the second uncoated portion 43 bmay have a conventional electrode structure or the electrode structure in other embodiments (modifications).The ends 81 of the first uncoated portion 43 aand the second uncoated portion 43 bmay be bent in the radial direction of the electrode assembly 80, for example, from the outer periphery toward the core. At this time, the second portion B 3 may be substantially not bent.FIG. 19 is a cross-sectional view of a jelly roll type electrode assembly 90 in which the electrode 45 of the second embodiment is applied to the first electrode (positive electrode) and the second electrode (negative electrode) along the Y-axis direction (winding axis direction).Referring to FIG. 19, the first uncoated portion 43 aof the first electrode includes a first portion B 1 adjacent to the core of the electrode assembly 90, a second portion B 3 adjacent to the outer circumferential surface of the electrode assembly 90, and a third portion B 2 disposed between the first portion B 1 and the second portion B 3.The height of the second portion B 3 is relatively smaller than that of the third portion B 2, and gradually or stepwise decreases from the core toward the outer periphery. Therefore, while pressing the bead portion of the battery case in the vicinity of the second portion B 3, it is possible to prevent a phenomenon in which an internal short circuit occurs when the bead portion and the second portion B 3 contact each other.The second uncoated portion 43 bhas the same structure as the first uncoated portion 43 a. In a modification, the second uncoated portion 43 bmay have a conventional electrode structure or an electrode structure of other embodiments (modifications).The ends 91 of the first uncoated portion 43 aand the second uncoated portion 43 bmay be bent in the radial direction of the electrode assembly 90, for example, from the outer periphery toward the core. At this time, the outermost side 92 of the second portion B 3 may be substantially not bent.FIG. 20 is a cross-sectional view of a jelly roll type electrode assembly 100 in which any one of the electrodes 50, 60, 70 of the third to fifth embodiments (modifications thereof) is applied to the first electrode (positive electrode) and the second electrode (negative electrode) along the Y-axis direction (winding axis direction).Referring to FIG. 20, the uncoated portion 43 aof the first electrode includes a first portion B 1 adjacent to the core of the electrode assembly 100, a second portion B 3 adjacent to the surface of the outer periphery of the electrode assembly 100, and a third portion B 2 disposed between the first portion B 1 and the second portion B 3.The height of the first portion B 1 is relatively smaller than that of the third portion B 2. In addition, in the third portion B 2, the bending length of the uncoated portion 43 alocated on the innermost side is equal to or less than the radial length (R) of the first portion B 1. The bending length (H) corresponds to a distance from the point at which the uncoated portion 43 ais bent to an upper end of the uncoated portion 43 a. In a modification, the bending length H may be less than the sum of the radial length (R) of the first portion B 1 and 10% of the radius of the core 102.Therefore, even when the third portion B 2 is bent, more than 90% of the diameter of the core 102 of the electrode assembly 100 is opened to the outside. The core 102 is a cavity in the center of the electrode assembly 100. When the core 102 is not blocked, there is no difficulty in the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding device through the core 102, a welding process between the negative electrode current collector (or the positive electrode) and the battery case (or the terminal) can be easily performed.The height of the second portion B 3 is relatively smaller than the height of the third portion B 2. Therefore, while pressing the bead portion of the battery case in the vicinity of the second portion B 3, it is possible to prevent a phenomenon in which an internal short circuit occurs when the bead portion and the second portion B 3 contact each other.In a modification, the height of the second portion B 3 may gradually or stepwise decrease in contrast to that shown in FIG. 20. In addition, in FIG. 20, the height of the third portion B 2 is equal in a part near the outer periphery, but the height of the third portion B 2 may gradually or stepwise increase from the boundary between the first portion B 1 and the third portion B 2 toward the boundary between the third portion B 2 and the second portion B 3. When the third portion B 2 is divided into a plurality of segments, a range in which the height of the uncoated portion 43 achanges corresponds to the variable segment height range ( 2 in FIG. 17 a ).The second uncoated portion 43 bhas the same structure as the first uncoated portion 43 a. In a modification, the second uncoated portion 43 bmay have a conventional electrode structure or an electrode structure of other embodiments (modifications).The ends 101 of the first uncoated portion 43 aand the second uncoated portion 43 bmay be bent in the radial direction of the electrode assembly 100, for example, from the outer periphery toward the core. At this time, the first portion B 1 and the second portion B 3 are substantially not bent.When the third portion B 2 has a plurality of segments, the bending stress may be reduced to prevent the uncoated portions 43 atoward the bending point from being torn or deformed abnormally. In addition, when the width and / or the height and / or the separation distance of the segments are adjusted according to the numerical range of the above embodiment, the segments are bent toward the core and overlapped in multiple layers enough to ensure sufficient welding strength, and no void hole (gap) is formed in the bending surface area.FIG. 21 is a cross-sectional view of an electrode assembly 110 according to still another embodiment of the present disclosure along the Y-axis direction (winding axis direction).Referring to FIG. 21, the electrode assembly 110 has substantially the same configuration as the electrode assembly 100 of FIG. 20 except that the height of the second portion B 3 is substantially equal to the height of the outermost side of the third portion B 2.The second section B 3 may include a plurality of segments. The configuration of the plurality of segments is substantially the same as that of the fourth and fifth embodiments (modifications) of the electrode.In the electrode assembly 110, the height of the first portion B 1 is relatively smaller than the height of the third portion B 2. In addition, in the third portion B 2, the bending length (H) of the uncoated portion located on the innermost side is equal to or less than the radial length (R) of the first portion B 1. Preferably, the first portion B1 may be a segment skip area (1 in Figure 17a) without a segment. In a modification, the bending length H may be less than the sum of the radial length (R) of the first portion B 1 and 10% of the radius of the core 112.Therefore, even when the third portion B 2 is bent, 90% or more of the diameter of the core 112 of the electrode assembly 110 is opened to the outside. When the core 112 is not blocked, there is no difficulty in the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, the welding process between the current collector on the negative electrode (or the positive electrode) and the battery case (or the terminal) can be easily performed by inserting a welding device through the core 112.In a modification, the structure in which the height of the third portion B 2 increases gradually or stepwise from the core toward the outer periphery may expand to the second portion B 3. In this case, the height of the uncoated portion 43 amay gradually or stepwise increase from the boundary between the first portion B 1 and the third portion B 2 toward the surface of the outermost side of the electrode assembly 110.The second uncoated portion 43 bhas the same structure as the first uncoated portion 43 a. In a modification, the second uncoated portion 43 bmay have a conventional electrode structure or the electrode structure of other embodiments (modifications).The ends 111 of the first uncoated portion 43 aand the second uncoated portion 43 bmay be bent in the radial direction of the electrode assembly 110, for example, from the outer periphery toward the core. At this time, the first portion B 1 is substantially not bent.When the third portion B 2 and the second portion B 3 have a plurality of segments, the bending stress is relaxed, so that it is possible to prevent cracking or abnormal deformation of the uncoated portions 43 a, 43 btoward the bending point. In addition, when the width and / or the height and / or the separation distance of the segment are adjusted according to the numerical ranges of the above embodiment, the segments are bent toward the core and overlapped in multiple layers enough to ensure sufficient welding strength, and no void hole (gap) is formed in the bending surface area.FIG. 22 is a cross-sectional view showing the electrode assembly 120 along the Y-axis direction (winding axis direction) according to still another embodiment of the present disclosure.Referring to FIG. 22, the electrode assembly 120 is substantially identical to the electrode assembly 100 of FIG. 20 except that the heights of the third portion B 2 have a pattern that gradually or stepwise increases and then decreases. The radial range in which the heights of the third portion B 2 change can be considered as the height-variable range ( 2 in FIG. 17 a ) of the segments. Even in this case, the height-variable range of the segments may be designed such that the stack number uniform range in which the stack number of the segments is 10 or more appears in the above-described desirable numerical range in the bending surface area F formed by bending the third portion B 2.The height change of the third portion B 2 can be realized by adjusting the height of the step pattern (see FIG. 14 c ) or the segment (see FIG. 14 dor FIG. 15 a ) included in the third portion B 2.In the electrode assembly 120, the height of the first portion B 1 is relatively smaller than the height of the third portion B 2. In addition, in the third portion B 2, the bending length H of the uncoated portion located on the innermost side is equal to or less than the radial length R of the first portion B 1. The area corresponding to the first portion B1 corresponds to the segment skip area (1 in Fig. 17a) without segment. In a modification, the bending length H may be less than the sum of the radial length R of the first portion B 1 and 10% of the radius of the core 122.Therefore, even when the third portion B 2 is bent toward the core, 90% or more of the diameter of the core 122 of the electrode assembly 120 is opened to the outside. When the core 122 is not blocked, there is no difficulty in the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding device through the core 122, the welding process can be easily performed between the negative electrode current collector (or the positive electrode) and the battery case (or the rivet terminal).In addition, the height of the second portion B 3 is relatively smaller than the heights of the third portion B 2, and preferably, the segment may not be formed in the second portion B 3. Therefore, it is possible to prevent the phenomenon that the bead portion and the second portion B 3 come into contact with each other to cause an internal short circuit while pressing the bead portion of the battery case in the vicinity of the second portion B 3. In a modification, the height of the second portion B 3 may gradually or stepwise decrease toward the outer periphery.The second uncoated portion 43 bhas the same structure as the first uncoated portion 43 a. In a modification, the second uncoated portion 43 bmay have a conventional electrode structure or an electrode structure of other embodiments (modifications).The ends 121 of the first uncoated portion 43 aand the second uncoated portion 43 bmay be bent toward the core from the outer periphery of the electrode assembly 120. At this time, the first portion B 1 and the second portion B 3 are substantially not bent.When the third portion B 2 has a plurality of segments, the bending stress is reduced to prevent the uncoated portions 43 a, 43 bfrom being torn or deformed abnormally. In addition, when the width and / or the height and / or the separation distance of the segments are adjusted according to the numerical range of the above embodiment, the segments are bent toward the core and overlapped in multiple layers enough to ensure sufficient welding strength, and no void hole (gap) is formed in the bending surface area.FIG. 23 is a cross-sectional view showing the electrode assembly 130 along the Y-axis direction (winding axis direction) according to still another embodiment of the present disclosure.Referring to FIG. 23, the electrode assembly 130 is substantially identical to the electrode assembly 120 of FIG. 22, except that the height of the second portion B 3 has a pattern that gradually or stepwise decreases from the boundary point of the second portion B 3 and the third portion B 2 toward the outermost surface of the electrode assembly 130.The height change of the second portion B 3 can be realized by expanding the step pattern (see FIG. 14 c ) included in the third portion B 2 toward the second portion B 3 and simultaneously gradually or stepwise decreasing the height of the pattern toward the outer periphery. In another modification, the change in height of the second portion B 3 may also be realized by expanding the segment structure of the third portion B 2 toward the second portion B 3 and simultaneously gradually or stepwise decreasing the height of the segment toward the outer periphery.In the electrode assembly 120, the height of the first portion B 1 is relatively smaller than the height of the third portion B 2. In addition, in the third portion B 2, the bending length H of the uncoated portion located on the innermost side is equal to or less than the radial length R of the first portion B 1. The first section B1 corresponds to the segment skip area (1 in Fig. 17a) without a segment. In a modification, the bending length H may be less than the sum of the radial length R of the first portion B 1 and 10% of the radius of the core 132.Therefore, even when the third portion B 2 is bent toward the core, 90% or more of the diameter of the core 132 of the electrode assembly 130 is opened to the outside. When the core 132 is not blocked, there is no difficulty in the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding device through the core 132, the welding process can be easily performed between the negative electrode current collector (or the positive electrode) and the battery case (or the terminal).The second uncoated portion 43 bhas the same structure as the first uncoated portion 43 a. In a modification, the second uncoated portion 43 bmay have a conventional electrode structure or the electrode structure of other embodiments (modifications).The ends 131 of the first uncoated portion 43 aand the second uncoated portion 43 bmay be bent toward the core from the outer periphery of the electrode assembly 130. At this time, the first portion B 1 is substantially not bent.When the third portion B 2 and the second portion B 3 have a plurality of segments, the bending stress is reduced to prevent the uncoated portions 43 a, 43 bfrom being torn or deformed abnormally near the bending point. In addition, when the width and / or the height and / or the separation distance of the segments are adjusted according to the numerical range of the above embodiment, the segments are bent toward the core and overlapped in multiple layers enough to ensure sufficient welding strength, and no void hole (gap) is formed in the bending surface area.Meanwhile, in the above embodiments (modifications), the ends of the first uncoated portion 43 aand the second uncoated portion 43 bmay be bent from the core toward the outer periphery. In this case, it is preferable that the second portion B 3 is configured to be bent as the segment skip portion ( 1 in FIG. 17 a ) without a segment and not toward the outer periphery. In addition, the radial width of the second portion B 3 may be equal to or greater than the bending length of the outermost uncoated portion (or segment) of the third portion B 2. In this case, when the outermost uncoated portion (or segment) of the third portion B 2 is bent toward the outer periphery, the end of the bent portion does not protrude toward the inner surface of the battery case beyond the outer periphery of the electrode assembly. In addition, the structure change pattern of the segments may be opposite to the above embodiments (modifications). For example, the heights of the segments may increase gradually or stepwise from the outer periphery toward the core. That is, by sequentially arranging the segment skip portion ( 1 in FIG. 17 a), the height variable portion ( 2 in FIG. 17 a), and the height uniformity portion ( 3 in FIG. 17 a) from the outer periphery of the electrode assembly toward the core, in the bending surface portion, the stack number uniformity portion in which the stack number of segments is 10 or more may appear in a desirable numerical range.Various electrode arrangement structures according to an embodiment of the present disclosure may be applied to a cylindrical battery.Preferably, the cylindrical battery may be, for example, a cylindrical battery whose shape factor ratio (defined as a value obtained by dividing the diameter of the cylindrical battery by height, namely, a ratio of diameter (Φ) to height (H)) is greater than about 0.4. Here, the shape factor means a value indicating the diameter and height of a cylindrical battery.Preferably, the cylindrical battery may have a diameter of 40 mm to 50 mm and a height of 60 mm to 130 mm. The shape factor of the cylindrical battery according to an embodiment of the present disclosure may be, for example, 46110, 4875, 48110, 4880, 4680, 4695. In the numerical value representing the form factor, the first two numbers indicate the diameter of the battery and the remaining numbers indicate the height of the battery. The winding turn of the electrode arrangement can be 50 turns to 60 turns.When an electrode assembly having a tabless structure is applied to a cylindrical battery having a form factor ratio of more than 0.4, the stress applied in the radial direction when the uncoated portion is bent is large, so that the uncoated portion can be easily torn off. In addition, when the current collector is welded to the bending surface area of the uncoated portion, it is necessary to sufficiently increase the number of stacked layers of the uncoated portion in the bending surface area to sufficiently ensure the welding strength and reduce the resistance. This requirement can be achieved by the electrode and the electrode assembly according to the embodiments (modifications) of the present disclosure.A battery according to an embodiment of the present disclosure may be an approximately cylindrical battery whose diameter is approximately 46 mm, whose height is approximately 110 mm, and whose aspect ratio is 0.418.A battery according to another embodiment may be an approximately cylindrical battery whose diameter is approximately 48 mm, whose height is approximately 75 mm, and whose shape factor ratio is 0.640.A battery according to still another embodiment may be an approximately cylindrical battery whose diameter is approximately 48 mm, whose height is approximately 110 mm, and whose shape factor ratio is 0.436.A battery according to still another embodiment may be an approximately cylindrical battery whose diameter is approximately 48 mm, whose height is approximately 80 mm, and whose aspect ratio is 0.600.A battery according to still another embodiment may be an approximately cylindrical battery whose diameter is approximately 46 mm, whose height is approximately 80 mm, and whose aspect ratio is 0.575.A battery according to still another embodiment may be an approximately cylindrical battery whose diameter is approximately 46 mm, whose height is approximately 95 mm, and whose aspect ratio is 0.484.Conventionally, batteries having a form factor ratio of about 0.4 or less have been used. That is, conventionally, for example, a 1865 battery, a 2170 battery, etc. have been used. The 1865 battery has a diameter of about 18 mm, a height of about 65 mm, and a form factor ratio of 0.277. The 2170 battery has a diameter of about 21 mm, a height of about 70 mm, and a form factor ratio of 0.300.Hereinafter, the cylindrical battery according to an embodiment of the present disclosure will be described in detail.FIG. 24 is a cross-sectional view showing a cylindrical battery 140 along the Y-axis direction according to an embodiment of the present disclosure.Referring to FIG. 24, the cylindrical battery 140 according to an embodiment of the present disclosure includes an electrode assembly 141 including a first electrode, a separator, and a second electrode, a battery case 142 for accommodating the electrode assembly 141, and a sealing body 143 for (sealing) closing an open end of the battery case 142.The battery case 142 is a cylindrical container having an opening at the top. The battery case 142 is made of a conductive metal material such as aluminum, steel, or stainless steel. A nickel plating layer may be formed on the surface of the battery case 142. The battery case 142 accommodates the electrode assembly 141 in the internal space through the upper opening and also accommodates the electrolyte.The electrolyte may be a salt having a structure such as A + B -. A + contains an alkaline metal cation such as Li +, Na + or K +, or a combination thereof. B - contains at least one anion selected from the group consisting of F -, Cl -, Br, I -, NO 3-, N(CN) 2-, BF 4-, ClO 4-, AlO 4-, AlCl 4-, PF6NER826_, SbF6NER828_, ASF6NER830_, bf_ner831_C 2 O 4-, BC 4 O 8-, ( CF 3)2 PF 4-, ( CF 3)3 PF 3-, ( CF 3)4 PF 2-, ( CF3)5PF-, (CF3)6P-, CF3SO3NER858_, C 4 F 9 SO 3-, CF 3 CF 2 SO 3-, ( CF 3 SO 2)2 N -, ( FSO 2)2 N-, CF3CF2(CF3)2CO-, (CF3SO2)2CH-, (SF5)3C-, (cf_ner886_so_ner887_)_ner88_c -, CF 3( CF 2)7 SO 3-, CF 3 CO 2-, CH 3 CO 2-, SCN - and (CF 3 CF2SO2)2N-select.The electrolyte may also be dissolved in an organic solvent. The organic solvent may use propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), γ-butyrolactone, or a mixture thereof.The electrode assembly 141 may have a jelly-roll shape, but the present disclosure is not limited thereto. The electrode assembly 141 may be manufactured by winding a laminate formed by successively laminating a lower separator, a first electrode, an upper separator, and a second electrode at least once with respect to the winding axis C, as shown in FIG. 2.The first electrode and the second electrode have different polarities. That is, when one has a positive polarity, the other has a negative polarity. At least one of the first electrode and the second electrode may have an electrode structure according to the above embodiments (modifications). In addition, the other of the first electrode and the second electrode may have a conventional electrode structure or an electrode structure according to embodiments (modifications). The pair of electrodes included in the electrode assembly 141 is not limited to one pair of electrodes, and two or more pairs of electrodes may be included.The first electrode uncoated portion 146 aand the second electrode uncoated portion 146 bprotrude at the upper portion and the lower portion of the electrode assembly 141, respectively. The first electrode has the electrode structure of the first embodiment (modification). Therefore, in the first uncoated portion 146 a, the height of the second portion B 3 is smaller than the height of the uncoated portion of the other region. The second portion B 3 is spaced apart from the inner periphery of the battery case 142, specifically, the bead portion 147, by a predetermined distance. Therefore, the second first electrode portion B 3 does not come into contact with the battery case 142 electrically connected to the second electrode, thereby preventing an internal short circuit of the battery 140.The second uncoated portion 146 bof the second electrode may have the same structure as the first uncoated portion 146 a. In another modification, the second uncoated portion 146 bmay selectively have the structures of the uncoated portions of the electrodes according to the embodiments (modifications).The seal body 143 may include a cap 143 awith a plate shape, a first seal 143 bfor providing airtightness between the cap 143 aand the battery case 142 and with insulation, and a connection plate 143 celectrically and mechanically coupled to the cap 143 a.The cap 143 ais a component made of a conductive metal material and covers the upper opening of the battery case 142. The cap 143 ais electrically connected to the first electrode uncoated portion 146 aand is electrically insulated from the battery case 142 by the first gasket 143 b. Accordingly, the cap 143 acan function as the first electrode (for example, positive electrode) of the cylindrical battery 140.The cap 143 ais placed on the bead portion 147 formed on the battery case 142, and is fixed by a crimping portion 148. Between the cap 143 aand the crimping portion 148, the first packing 143 bmay be disposed to secure airtightness of the battery case 142 and electrical insulation between the battery case 142 and the cap 143 a. The cap 143 amay include a protrusion 143 dprotruding upward from the center thereof.The battery case 142 is electrically connected to the second uncoated portion 146 bof the second electrode. Therefore, the battery case 142 has the same polarity as the second electrode. When the second electrode has a negative polarity, the battery case 142 also has a negative polarity.The battery case 142 includes the bead portion 147 and the crimp portion 148 at the top thereof. The bead portion 147 is formed by press-fitting the periphery of the outer peripheral surface of the battery case 142. The bead portion 147 prevents the electrode assembly 141 accommodated in the battery case 142 from leaking through the upper opening of the battery case 142, and can function as a support portion on which the sealing body 143 is placed.The inner periphery of the bead portion 147 may be spaced apart from the first electrode second portion B 3 by a predetermined distance. Specifically, the lower end of the inner periphery of the bead portion 147 is separated from the first electrode second portion B 3 by a predetermined distance. In addition, since the second portion B 3 has a small height, the second portion B 3 is not significantly affected even when the battery case 142 is press-fitted on the outside to form the bead portion 147. Therefore, the second portion B 3 is not pressed by other components such as the bead portion 147, and thus partial shape deformation of the electrode assembly 141 is prevented, thereby preventing a short circuit in the cylindrical battery 140.When the press-fit depth of the bead portion 147 is defined as D 1 and the radial length from the inner periphery of the battery case 142 to the boundary point between the second portion B 3 and the third portion B 2 is defined as D 2, the relational expression D 1≤D 2 may be preferably satisfied. In this case, when the battery case 142 is press-fitted to form the bead portion 147, it is possible to substantially prevent the second portion B 3 from being damaged.The crimping portion 148 is formed on the bead portion 147. The crimping portion 148 has an elongated and bent shape to cover the outer periphery of the cap 143 adisposed on the bead portion 147 and a part of the upper surface of the cap 143 a.The cylindrical battery 140 may further include a first current collector 144 and / or a second current collector 145 and / or an insulator 146.The first current collector 144 is coupled to the upper portion of the electrode assembly 141. The first current collector 144 is made of a conductive metal material such as aluminum, copper, steel, nickel, and so forth, and is electrically connected to the first uncoated portion 146 aof the first electrode. The electrical connection can be produced by welding. A line 149 may be connected to the first current collector 144. The lead 149 may extend upward over the electrode assembly 141 and be coupled to the connection plate 143 cor directly coupled to the lower surface of the cap 143 a. The conduit 149 may be connected to other components by welding.Preferably, the first current collector 144 may be integrally formed with the lead 149. In this case, the lead 149 may have an elongated plate shape extending outward from near the center of the first current collector 144.The first current collector 144 may have a plurality of irregularities (not shown) formed radially on its bottom surface. When the radial irregularities are provided, the irregularities may be press-fitted into the first uncoated portion 146 aof the first electrode by pressing the first current collector 144.The first current collector 144 is coupled to an end of the first uncoated portion 146 a. The first uncoated portion 146 aand the first current collector 144 may be coupled by laser welding, for example. Laser welding may be performed by partially melting a base material of the current collector 144. In a modification, the first current collector 144 and the first uncoated portion 146 amay be welded with a solder interposed therebetween. In this case, the solder may have a lower melting point as compared to the first current collector 144 and the first uncoated portion 146 a. The laser welding may be replaced by resistance welding, ultrasonic welding, spot welding, or the like.The second current collector 145 may be coupled to the lower surface of the electrode assembly 141. One side of the second current collector 145 may be coupled to the second uncoated portion 146 bby welding, and the other side may be coupled to the inner lower surface of the battery case 142 by welding. The coupling structure between the second current collector 145 and the second uncoated portion 146 bmay be substantially the same as the coupling structure between the first current collector 144 and the first uncoated portion 146 a.Welding the first current collector 144 and / or the second current collector 145 may prevent the electrodes from rotating as the electrode assembly 141 swells. In other words, welding the first current collector 144 and / or the second current collector 145 may improve the effect of the winding structure of the electrode assembly to prevent or reduce the collapse of the core. This effect appears identical in embodiments described later.The uncoated portions 146 a, 146 bare not limited to the illustrated structure. Accordingly, the uncoated portions 146 a, 146 bmay selectively have a conventional structure of the uncoated portions as well as the structure of the uncoated portions of the electrodes according to the embodiments (modifications).The insulator 146 may cover the first current collector 144. The insulator 146 may cover the first current collector 144 on the upper surface of the first current collector 144, thereby preventing direct contact between the first current collector 144 and the inner periphery of the battery case 142.The insulator 146 has a lead hole 151 so that the lead 149 extending upward from the first current collector 144 can be pulled out thereby. The lead 149 is pulled up through the lead hole 151 and coupled to the lower surface of the connecting plate 143 cor the lower surface of the cap 143 a.A peripheral portion of the edge of the insulator 146 may be disposed between the first current collector 144 and the bead portion 147 to fix the coupled body of the electrode assembly 141 and the first current collector 144. Accordingly, the movement of the coupled body of the electrode assembly 141 and the first current collector 144 in the winding axis direction Y of the battery 140 can be restricted, thereby improving the assembly stability of the battery 140.The insulator 146 may be made of an insulating polymer resin. In one example, the insulator 146 may be made of polyethylene, polypropylene, polyimide, or polybutylene terephthalate.The battery case 142 may further include a vent portion 152 formed on a lower surface thereof. The vent portion 152 corresponds to a region having a smaller thickness as compared with the peripheral region of the lower surface of the battery case 142. The vent portion 152 is structurally weak compared to the surrounding area. Accordingly, when abnormality occurs in the cylindrical battery 140 and the internal pressure increases to a predetermined level or more, the vent portion 152 may be broken so that the gas generated inside the battery case 142 is discharged to the outside. The internal pressure at which the vent portion 152 is broken may be about 15 kgf / cm 2 to 35 kgf / cm 2.The vent portion 152 may be formed continuously or discontinuously while a circle is drawn on the lower surface of the battery case 142. In a modification, the vent portion 152 may be formed in a straight pattern or other patterns.FIG. 25 is a cross-sectional view showing a cylindrical battery 150 along the Y-axis direction according to an embodiment of the present disclosure.Referring to FIG. 25, the cylindrical battery 150 has substantially the same configuration as the cylindrical battery 140 of FIG. 24, except that the electrode structure of the second embodiment (modification) is adopted in the first uncoated portion 146 aof the first electrode.Referring to FIG. 25, the first uncoated portion 146 aof the first electrode may have a shape in which the height of the second portion B 3 gradually or stepwise decreases toward the inner periphery of the battery case 142. Preferably, an imaginary line connecting the top of the second portion B 3 may have the same or similar shape as the inner periphery of the bead portion 147.The second portion B 3 forms an inclined surface. Therefore, when the battery case 142 is press-fitted to form the bead portion 147, the second portion B 3 can be prevented from being compressed and damaged by the bead portion 147. In addition, it is possible to suppress a phenomenon in which the second portion B 3 contacts the battery case 142 having a different polarity and causing an internal short circuit.The other configuration of the cylindrical battery 150 is substantially the same as the above-described embodiment (modification).The uncoated portions 146 a, 146 bare not limited to the illustrated structure. Accordingly, the uncoated portions 146 a, 146 bmay selectively have a conventional structure of the uncoated portions as well as the structure of the uncoated portions of the electrodes according to the embodiments (modifications).FIG. 26 is a cross-sectional view showing a cylindrical battery 160 along the Y-axis direction according to still another embodiment of the present disclosure.Referring to FIG. 26, the cylindrical battery 160 is substantially the same as the above-described cylindrical batteries 140, 150 except that the lead 149 connected to the first current collector 144 is directly connected to the cap 143 aof the sealing body 143 through the lead hole 151 of the insulator 146, and the insulator 146 and the first current collector 144 have a structure in close contact with the lower surface of the cap 143 a.In the cylindrical battery 160, the diameter of the first current collector 144 and the diameter of the outermost side of the third portion B 2 are smaller than the minimum inner diameter of the battery case 142. In addition, the diameter of the first current collector 144 may be equal to or larger than the diameter of the outermost side of the third portion B 2.Specifically, the minimum inner diameter of the battery case 142 may correspond to the inner diameter of the battery case 142 at a position where the bead portion 147 is formed. At this time, the outermost diameters of the first current collector 144 and the third portion B 2 are smaller than the inner diameter of the battery case 142 at the position where the bead portion 147 is formed. In addition, the diameter of the first current collector 144 may be equal to or larger than the outermost diameter of the third portion B 2. The peripheral portion of the edge of the insulator 146 may be disposed between the second portion B 3 and the bead portion 147 in a state of being bent downward to fix the coupled body of the electrode assembly 141 and the first current collector 144.Preferably, the insulator 146 has a portion covering the second portion B 3 and a portion covering the first current collector 144, and a portion connecting the two portions may have a curved shape corresponding to the curved shape of the bead portion 147. The insulator 146 can insulate the inner periphery of the second portion B 3 and the bead portion 147 and simultaneously insulate the first current collector 144 and the inner periphery of the bead portion 147.The first current collector 144 may be disposed higher than the lower end of the bead portion 147 and may be coupled to the first portion B 1 and the third portion B 2. At this time, the press-fit depth D 1 of the bead portion 147 is equal to or smaller than the distance D 2 from the inner periphery of the battery case 142 to the boundary between the second portion B 3 and the third portion B 2. Accordingly, the first portion B 1 and the third portion B 2 and the first current collector 144 coupled thereto may be disposed higher than the lower end of the bead portion 147. The lower end of the bead portion 147 means a bending point B between the portion of the battery case 142 in which the electrode assembly 141 is accommodated and the bead portion 147.Since the first portion B 1 and the third portion B 2 occupy the inner space of the bead portion 147 in the radial direction, the empty space between the electrode assembly 141 and the cap 143 acan be minimized. In addition, the connection plate 143 cdisposed in the empty space between the electrode assembly 141 and the cap 143 ais omitted. Therefore, the lead 149 of the first current collector 144 may be directly coupled to the lower surface of the cap 143 a. According to the above structure, the empty space in the battery is reduced, and the energy density can be maximized up to the reduced empty space.In the cylindrical battery 160, the first current collector 144 and the second current collector 145 can be welded to the ends of the first and second uncoated portions 146 a, 146 bin the same manner as in the above embodiment, respectively.The uncoated portions 146 a, 146 bare not limited to the illustrated structure. Accordingly, the uncoated portions 146 a, 146 bmay selectively have a conventional structure of the uncoated portions as well as the structure of the uncoated portions of the electrodes according to the embodiments (modifications).FIG. 27 is a cross-sectional view showing a cylindrical battery 170 along the Y-axis direction according to an embodiment of the present disclosure.Referring to FIG. 27, the structure of the electrode assembly of the cylindrical battery 170 is substantially the same as that of the cylindrical battery 140 of FIG. 17, and the other structure except for the electrode assembly is changed.Specifically, the cylindrical battery 170 includes a battery case 171 through which a terminal 172 is installed. The terminal 172 is installed through a perforation hole formed in the closed surface (the upper surface in the drawing) of the battery case 171. The terminal 172 is riveted to the perforation hole of the battery case 171 in a state where a second packing 173 made of an insulating material is interposed therebetween. The terminal 172 is exposed to the outside in a direction opposite to the gravity direction.The terminal 172 includes a terminal exposing portion 172 aand a terminal inserting portion 172 b. The terminal exposing portion 172a is exposed to the outside of the closed surface of the battery case 171. The terminal exposing portion 172 amay be located at approximately a middle portion of the closed surface of the battery case 171. The maximum diameter of the terminal exposing portion 172a may be larger than the maximum diameter of the perforation hole formed in the battery case 171. The terminal insert portion 172 bmay be electrically connected to the first electrode uncoated portion 146 athrough approximately the central portion of the closed surface of the battery case 171. The lower edge of the terminal insertion portion 172 bmay be riveted to the inner surface of the battery case 171. That is, the lower edge of the terminal insertion portion 172 bmay have a shape curved toward the inner surface of the battery case 171. A flat portion 172c is included on the inner side of the lower edge of the terminal fitting portion 172b. The maximum diameter of the lower portion of the riveted terminal insertion portion 172 bmay be larger than the maximum diameter of the perforation hole of the battery case 171.The flat portion 172 cof the terminal insert portion 172 bmay be welded to the central portion of the first current collector 144 connected to the first uncoated portion 146 aof the first electrode. Welding may be replaced by other welding methods, such as ultrasonic welding.An insulator 174 made of an insulating material may be disposed between the first current collector 144 and the inner surface of the battery case 171. The insulator 174 covers the upper portion of the first current collector 144 and the upper edge of the electrode assembly 141. Accordingly, it is possible to prevent the second portion B 3 of the electrode assembly 141 from contacting the inner surface of the battery case 171 having a different polarity to cause a short circuit.The thickness of the insulator 174 corresponds to or is slightly larger than the distance between the upper surface of the first current collector 144 and the inner surface of the closed portion of the battery case 171. Accordingly, the insulator 174 can contact the upper surface of the first current collector 144 and the inner surface of the closed portion of the battery case 171.The terminal insertion portion 172 bof the terminal 172 may be welded to the first current collector 144 through the perforation hole of the insulator 174. A diameter of the perforation hole formed in the insulator 174 may be larger than a diameter of the rivet portion at the lower end of the terminal insertion portion 172 b. Preferably, the perforation hole may expose the lower portion of the terminal insertion portion 172 band the second packing 173.The second packing 173 is disposed between the battery case 171 and the terminal 172 to prevent the battery case 171 and the terminal 172 having opposite polarities from electrically contacting each other. Accordingly, the upper surface of the battery case 171 having an approximately flat shape can function as the second electrode (for example, negative electrode) of the cylindrical battery 170.The second packing 173 includes a packing exposing portion 173 aand a packing inserting portion 173 b. The seal exposing portion 173 ais disposed between the terminal exposing portion 172 aof the terminal 172 and the battery case 171. The seal insert portion 173 bis disposed between the terminal insert portion 172 bof the terminal 172 and the battery case 171. The seal insert portion 173 bmay be deformed together when the terminal insert portion 172 bis riveted to be in close contact with the inner surface of the battery case 171. The second gasket 173 may be made of, for example, a polymer resin having an insulating property.The seal exposing portion 173 aof the second seal 173 may have an elongated shape to cover the outer periphery of the terminal exposing portion 172 aof the terminal 172. When the second packing 173 covers the outer periphery of the terminal 172, it is possible to prevent a short circuit from occurring while an electrical connection part such as a bus bar is coupled to the upper surface of the battery case 171 and / or the terminal 172. Although not shown in the drawings, the seal exposing portion 173 amay have an elongated shape to cover not only the outer circumferential surface of the terminal exposing portion 172 abut also a part of the upper surface thereof.When the second gasket 173 is made of a polymer resin, the second gasket 173 may be coupled to the battery case 171 and the terminal 172 by thermal fusion. In this case, airtightness at the coupling interface between the second packing 173 and the terminal 172, and at the coupling interface between the second packing 173 and the battery case 171 can be improved. Meanwhile, when the seal exposing portion 173 aof the second seal 173 has a shape extending to the upper surface of the terminal exposing portion 172 a, the terminal 172 may be integrally coupled to the second seal 173 by insert molding.In the upper surface of the battery case 171, a remaining portion 175 different from the portion occupied by the terminal 172 and the second packing 173 corresponds to the second electrode terminal having a polarity opposite to that of the terminal 172.The second current collector 176 is coupled to the lower portion of the electrode assembly 141. The second current collector 176 is made of a conductive metal material such as aluminum, steel, copper, or nickel, and is electrically connected...

Claims

A cylindrical battery, comprising: an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding axis of the electrode assembly to define a core and an outer periphery of the electrode assembly; and a cylindrical battery case accommodating the electrode assembly, wherein a cross section of the electrode assembly perpendicular to the winding axis direction includes a first fan-shaped portion and a second fan-shaped portion each including a circumferential angle of 180 degrees or less in a winding direction, wherein the first fan-shaped portion is defined by a first straight line and a second straight line passing from a center of the core through a core-side end of the first electrode and a core-side end of the second electrode, respectively, and by an outer periphery of the first fan-shaped portion along the winding direction as a stress-prone portion, wherein a second fan-shaped portion is defined as a stress strengthening portion by a third straight line and a fourth straight line passing from the center of the core through an outer circumferential side end of the first electrode and an outer circumferential side end of the second electrode, respectively, and by an outer circumference of the second fan-shaped portion along the winding direction, and wherein the electrode assembly has a winding structure in which at least the outer circumferential side end of the first electrode of the stress strengthening portion is spaced apart from an inner side of the stress prone portion along a circumferential direction of the cross section of the electrode assembly.The cylindrical battery according to claim 1, wherein a portion of the outer periphery of the electrode assembly where the outer peripheral side end of the first electrode is located is in close contact with an inner surface of the battery case.The cylindrical battery according to claim 1, wherein in the winding structure, the voltage enhancing portion is spaced apart from the voltage susceptible portion along the circumferential direction of the cross section of the electrode assembly.The cylindrical battery according to claim 1, wherein the cross section includes a first semicircular region and a second semicircular region based on a diametrical line segment, the diametrical line segment passing through a center of the core and being perpendicular to a straight line dividing a circumferential angle of the stress-susceptible region into equal angles, wherein, in the winding structure, the stress-susceptible region is located in the first semicircular region and the stress-enhancing region is located in the second semicircular region.The cylindrical battery according to claim 1, wherein, in the winding structure, at least a part of the voltage enhancing portion overlaps with a third fan-shaped portion in the second semicircular portion, the third fan-shaped portion being point-symmetric with the voltage susceptible portion with respect to the center of the core.The cylindrical battery according to claim 5, wherein in the winding structure, at least a part of the voltage boosting portion overlaps with a fifth straight line that divides a circumferential angle of the third fan-shaped portion into equal angles.The cylindrical battery according to claim 1, wherein when a fifth straight line divides a third fan-shaped region into equal angles, the fifth straight line is point-symmetric with the stress-prone region with respect to the center of the core, wherein, in the winding structure, the third straight line and the fourth straight line are located between the second straight line and the fifth straight line with respect to the circumferential direction of the cross section.The cylindrical battery according to claim 1, wherein when a fifth straight line divides a third fan-shaped region into equal angles, the fifth straight line is point-symmetric with the stress-prone region with respect to the center of the core, wherein, in the winding structure, the third straight line and the fourth straight line are located between the first straight line and the fifth straight line with respect to the circumferential direction of the cross section.The cylindrical battery according to claim 1, wherein when a fifth straight line divides a third fan-shaped region into equal angles, the fifth straight line is point-symmetric with the stress-prone region with respect to the center of the core, wherein, in the winding structure, the fourth straight line is located between the fifth straight line and the first straight line, and the third straight line is located between the fourth straight line and the second straight line with respect to the circumferential direction of the cross section.The cylindrical battery according to claim 1, wherein when a fifth straight line divides a third fan-shaped region into equal angles, the fifth straight line is point-symmetric with the stress-prone region with respect to the center of the core, wherein, in the winding structure, the fourth straight line is located between the fifth straight line and the first straight line, and the third straight line is located between the fifth straight line and the second straight line with respect to the circumferential direction of the cross section.The cylindrical battery according to claim 1, wherein when a fifth straight line divides a third fan-shaped region into equal angles, the fifth straight line is point-symmetric with the stress-prone region with respect to the center of the core, wherein, in the winding structure, the fourth straight line is located between the fifth straight line and the second straight line, and the third straight line is located between the fourth straight line and the first straight line with respect to the circumferential direction of the cross section.The cylindrical battery according to claim 1, wherein when a fifth straight line divides a third fan-shaped region into equal angles, the fifth straight line is point-symmetric with the stress-prone region with respect to the center of the core, wherein, in the winding structure, the fourth straight line is located between the fifth straight line and the second straight line, and the third straight line is located between the fifth straight line and the first straight line with respect to the circumferential direction of the cross section.The cylindrical battery according to claim 1, wherein the winding structure has a circumferential angle between the first straight line and the fourth straight line that is larger than a circumferential angle between the second straight line and the third straight line with respect to the circumferential direction of the cross section.The cylindrical battery according to claim 1, wherein the winding structure has a circumferential angle between the second straight line and the fourth straight line that is larger than a circumferential angle between the first straight line and the third straight line with respect to the circumferential direction of the cross section.The cylindrical battery according to claim 1, wherein the winding structure has a circumferential angle of the voltage enhancing portion smaller than a circumferential angle of the voltage susceptible portion with respect to the center of the core.The cylindrical battery according to any one of claims 1 to 15, wherein the winding structure of the electrode assembly is maintained in a range of 200 cycles or more, 300 cycles or more, 400 cycles or more, 500 cycles or more, 600 cycles or more, 700 cycles or more, 800 cycles or more, or 900 cycles or more during charging and discharging.The cylindrical battery of claim 1, wherein the first electrode and the second electrode are a positive electrode and a negative electrode, respectively, wherein the first electrode has a plurality of negative electrode winding turns, wherein at least a part of the plurality of negative electrode winding turns is provided adjacent to a core side of the electrode assembly, and wherein the at least a part of the negative electrode winding turns extends in a radial direction.The cylindrical battery according to claim 17, wherein the separator has a plurality of winding turns provided on an inner side of the winding turns of the negative electrode.The cylindrical battery according to claim 1, wherein the first electrode and the second electrode are a positive electrode and a negative electrode, respectively, wherein the core-side end of the second electrode further extends in a direction opposite to the winding direction than the core-side end of the first electrode to thereby define at least a part of an innermost winding turn, and wherein the outer circumferential-side end of the second electrode further extends in the winding direction than the outer circumferential-side end of the first electrode to thereby define at least a part of an outermost winding turn.The cylindrical battery according to claim 1, wherein, in the winding structure, a circumferential angle of the stress-susceptible portion has an angle in a range of 180 degrees or less, and a circumferential angle of the stress enhancing portion has an angle in a range of 10 degrees or more and 90 degrees or less.The cylindrical battery according to claim 20, wherein, in the winding structure, the circumferential angle of the stress-susceptible portion has an angle in a range of 87 degrees or more, and the circumferential angle of the stress enhancing portion has an angle in a range of 32 degrees or less.The cylindrical battery according to claim 1, wherein the battery case has an open end and a bottom portion opposite thereto, and accommodates the electrode assembly in the space between the open end and the bottom portion, the battery case being electrically connected to one of the first electrode or the second electrode to have a first polarity.The cylindrical battery according to claim 22, further comprising: a sealing body that closes the open end of the battery case; and a terminal electrically connected to the other of the first electrode and the second electrode to have a second polarity, the terminal having a surface exposed to an outside of the battery case.The cylindrical battery according to claim 1, wherein the first electrode has a first uncoated portion at a long side end along a winding direction of the electrode assembly, the first uncoated portion extends from the separator through an end of the electrode assembly and protrudes outward and is in a bent state in a radial direction of the electrode assembly to define a first bending surface area, and wherein the cylindrical battery further has a first current collector welded to the first bending surface area.The cylindrical battery according to claim 24, wherein the first uncoated portion includes a plurality of segments along the winding direction of the electrode assembly, and wherein the plurality of segments are in a bent state in the radial direction of the electrode assembly to define the first bending surface area.The cylindrical battery according to claim 1, wherein the second electrode has a second uncoated portion at a long side end along the winding direction, the second uncoated portion extends from the separator through the other end of the electrode assembly and protrudes outward and is in a bent state toward the core to define a second bending surface area, and wherein the cylindrical battery further has a second current collector welded to the second bending surface area.The cylindrical battery according to claim 26, wherein the second uncoated portion includes a plurality of segments along the winding direction of the electrode assembly, and wherein the plurality of segments are in a bent state in a radial direction of the electrode assembly to define the second bending surface area.The cylindrical battery according to claim 24 or 25, wherein a welding portion of the first current collector has a radial structure.The cylindrical battery according to claim 26 or 27, wherein a welding portion of the second current collector has a radial structure.The cylindrical battery of claim 1, wherein a ratio of a diameter to a height is greater than 0.4.The cylindrical battery of claim 30, wherein the cylindrical battery has a shape factor of 46110, 4875, 48110, 4880, 4680, or 4695.A battery pack comprising a plurality of cylindrical batteries according to any one of claims 1 to 31.A vehicle comprising the battery pack according to claim 32.

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