Electrode assembly, battery and battery pack and a vehicle comprising the same

Abstract

Battery (190), comprising: an electrode assembly (110) in which a first electrode (10; 11), a second electrode (10; 11), and a separator (12) arranged therebetween are wound with respect to an axis and thereby define a core (C) and an outer periphery, wherein at least one of the first electrode (10; 11) and the second electrode (10; 11) has an uncoated portion (43) adjacent to an edge of the respective electrode (10; 11), wherein the uncoated portion (43) extends beyond the separator (12) along a winding axis direction of the electrode assembly (110), and wherein at least a part of the uncoated portion (43) is bent in a radial direction of the electrode assembly (110) to form a bending surface region (F), wherein in a partial region of the bending surface region (F), the number of stacked layers of the uncoated portion (43) is 10 or more; a battery case (171) configured to receive the electrode assembly (110) and electrically connected to one of the first electrode (10; 11) and the second electrode (10; 11) and thereby having a first polarity; a closure body (178) configured to close an open end of the battery case (171); a terminal (172) mounted through a hole in an end of the battery case (171) opposite the open end and electrically connected to the other of the first electrode (10; 11) and the second electrode (10; 11), thereby having a second polarity and configured to have an outwardly exposed surface, the terminal (172) comprising an exposed terminal portion (172a) and an insertion portion (172b), the exposed terminal portion (172a) being exposed to the outside at the end of the battery case (171) opposite the open end, and the insertion portion (172b) being riveted to an inner surface of the battery case (171) at the end of the battery case (171) opposite the open end; a seal (173) made of an insulating material arranged between the battery case (171) and the terminal (172); a current collector (176) welded to the bending surface region (F) and electrically connected to one of the battery case (171) and the terminal (172), wherein the welding area of ​​the current collector (176) overlaps the bending surface area (F) in which the number of stacked layers of the uncoated portion (43) is 10 or more, wherein the partial region of the bending surface region (F) extends circularly around a winding axis or is an annular region.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an electrode assembly, a battery and a battery pack, and a vehicle including the same. STATE OF THE ART

[0002] Secondary batteries, which are easily applicable to various product groups and have electrical properties such as high energy density, are universally used not only for portable devices but also for electric vehicles (EVs) or hybrid electric vehicles (HEVs) powered by an electric power source.

[0003] These secondary batteries are attracting attention as a new energy source to improve environmental friendliness and energy efficiency because they have the main advantage of drastically reducing the use of fossil fuels and the secondary advantage of not producing any by-products from energy use.

[0004] Secondary batteries currently in widespread use include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and the like. A secondary battery unit, i.e., a unit battery, has an operating voltage of approximately 2.5V to 4.5V. Consequently, a battery pack can be configured by connecting multiple batteries in series when a higher output voltage is required. In addition, multiple batteries can 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 contained in the battery pack and the form of electrical connection can be varied according to the required output voltage and / or charge / discharge capacity.

[0005] Meanwhile, cylindrical, rectangular, and pouch-type batteries are known as types of secondary battery units. 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 structure, which is inserted into a battery case to configure a battery. In addition, a strip-shaped electrode tab may be connected to an uncoated portion of each of the positive electrode and the negative electrode, and the electrode tab electrically connects the electrode assembly and an externally exposed electrode terminal. For reference, the positive electrode terminal is a cap of a sealing body that seals the opening of the battery case, and the negative electrode terminal is the battery case.However, according to the conventional cylindrical battery having such a structure, the current collection efficiency is not good due to a large resistance and a large heat generation because 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.

[0006] For small cylindrical batteries with a form factor of 1865 (diameter: 18 mm, height: 65 mm) or a form factor of 2170 (diameter: 21 mm, height: 70 mm), resistance and heat are not a major concern. However, if the form factor is increased to fit the cylindrical battery to an electric vehicle, the cylindrical battery could self-ignite if excessive heat is generated around the electrode tab during a fast-charging process.

[0007] To solve this problem, a cylindrical battery (so-called tabless cylindrical battery) is provided in which the uncoated portion of the positive electrode and the uncoated portion of the negative electrode are designed to be positioned at the top and bottom of the jelly-roll electrode assembly, respectively, and the current collector is welded to the uncoated portion to improve the current collection efficiency. DESCRIPTION

[0008] Fig. 1 to Fig. 3 schematically show a manufacturing process of a tabless, cylindrical battery. Fig. 1 shows the structure of an electrode, Fig. 2 shows a winding process of the electrode and Fig. 3 shows a welding process of a current collector to a bending surface area of ​​an uncoated section.

[0009] With reference to Fig. 1 to Fig. 3, a positive electrode 10 and a negative electrode 11 have a structure in which a plate-shaped current collector 20 is coated with an active material 21, which comprises an uncoated portion 22 on a long side along the winding direction X.

[0010] An electrode assembly A is formed by sequentially stacking the positive electrode 10 and the negative electrode 11 together with two separator plates 12 as shown in Fig. 2, 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. The positions of the positive electrode 10 and the negative electrode 11 can be changed opposite to those shown in the figures.

[0011] After the winding process, the uncoated portion 10a of the positive electrode 10 and the uncoated portion 11a of the negative electrode 11 are bent toward the core to form a bending surface area. Current collectors 30, 31 are then welded and coupled to the uncoated portions 10a and 11a, respectively.

[0012] An electrode tab is not separately coupled to the uncoated portion 10a of the positive electrode and the uncoated portion 11a of the negative electrode. The current collectors 30, 31 are connected to external electrode terminals, and a current path with a large cross-sectional area is formed along the winding axis direction of the electrode assembly A (see arrow), which has the advantage of reducing the battery's resistance. This is because the resistance is inversely proportional to the cross-sectional area of ​​the path through which the current flows.

[0013] In the tabless cylindrical battery, in order to improve the welding properties between the uncoated sections 10a, 11a and the current collectors 30, 31, strong pressure must be applied to the welding areas of the uncoated sections 10a, 11a to bend the uncoated sections 10a, 11a as flat as possible.

[0014] When the uncoated portions 10a, 11a are bent, all or a significant portion of the cavity 33 in the core of the electrode assembly A is blocked because the uncoated portion 32 is bent adjacent to the core of the electrode assembly A. In this case, problems are caused in the electrolyte injection process. That is, the cavity 33 in the core of the electrode assembly A is used as a passage through which an electrolyte is introduced. However, if the corresponding passage is blocked, electrolyte injection is difficult. In addition, while an electrolyte injector is inserted into the cavity 33, the electrolyte injector may collide with the uncoated portion 32 bent near the core, which may cause the uncoated portion 32 to crack.

[0015] In addition, the bent portions of the uncoated sections 10a, 11a to which the current collectors 30, 31 are welded should be overlapped in multiple layers, and there should be no gaps. In this way, sufficient welding strength can be achieved, and even with the latest technology, such as laser welding, laser penetration into the electrode assembly A and melting the separator or active material can be prevented.

[0016] In order for the uncoated sections 10a, 11a to be superimposed in the same number of layers, the uncoated sections 10a, 11a must be bent toward the core at the corresponding positions according to the position of each winding turn (winding turn), covering the surface of the bent uncoated section of the innermost winding turn. Furthermore, assuming that the interval between winding turns is d and the bending length of the uncoated sections 10a, 11a of each winding turn is e, the bending length e must be greater than d*n (n is a natural number greater than or equal to 2). Only in this case is a region formed in which the uncoated sections 10a, 11a are overlapped in multiple layers of the same amount.Furthermore, to sufficiently obtain an area where the uncoated portions 10a, 11a overlap substantially the same number in the radial direction of the electrode assembly, the uncoated portions 10a, 11a must have a sufficient length. However, since the electrode assembly included in a small cylindrical battery has a small radius, it is difficult to see any motivation for deriving the concept of designing the uncoated portions 10a, 11a with a sufficiently long bending length. TECHNICAL TASK

[0017] The present disclosure is designed to solve the problems of the prior art, and therefore, the present disclosure is directed to providing an electrode assembly having an uncoated portion of a bent structure, which can prevent a separator or an active material layer from being damaged during welding of a current collector by sufficiently securing a region where uncoated portions are overlapped in a radial direction of an electrode assembly in 10 or more layers when the uncoated portions exposed at both ends of the electrode assembly are bent.

[0018] The present disclosure is also directed to providing an electrode assembly in which an electrolyte injection passage is not blocked even if the uncoated portion is bent.

[0019] The present disclosure is also directed to providing an electrode assembly with improved energy density and reduced resistance.

[0020] The present disclosure is also directed to providing a battery including the electrode assembly with an improved structure, a battery pack including the battery, and a vehicle including the battery pack.

[0021] The technical problems to be solved by the present disclosure are not limited to the above, and other problems not mentioned here will become clear to those skilled in the art from the following disclosure.

[22] SUMMARY OF THE INVENTION

[0022] The present invention is defined by the subject matter of the independent claims. Particular examples of the implementation of the present invention are defined by the features of the dependent claims. The claimed subject matter may include any of the features defined above with reference to Fig. 1 to Fig. 3 unless otherwise stated or unreasonable.

[0023] An electrode assembly may be provided, in particular an electrode assembly for a battery, in particular an electrode assembly for a secondary battery. The electrode assembly comprises a first electrode, a second electrode, and a separator arranged between the first electrode and the second electrode.

[0024] The outer periphery of the wound first and second electrodes and the separator disposed therebetween may have a generally cylindrical shape. The wound first and second electrodes and the separator disposed therebetween may have a cross-section corresponding to a spiral shape. The core may include a generally cylindrical cavity. The description "generally cylindrical" as used herein with reference to the wound first and second electrodes and the separator disposed therebetween should be understood to refer to the inner and / or outer cylindrical surface, which may have a step-like transition at the inner or outer terminal winding edge, respectively, with respect to the penultimate winding. The terminal winding edge may extend parallel to the winding axis. The terminal winding edge may alternatively be referred to as a short side end.

[0025] An electrode assembly may be provided in which a first electrode, a second electrode, and a separator disposed therebetween are wound along an axis to define a core and an outer periphery, wherein the first electrode includes an uncoated portion adjacent to an edge of the first electrode (e.g., at a long side end thereof). The uncoated portion extends beyond (and / or may be exposed from) the separator along a winding axis direction of the electrode assembly, particularly at the edge of the first electrode.A portion of the uncoated portion is bent in a radial direction of the electrode assembly to form a bending surface area including overlapping layers of the uncoated portion, and in a partial area of ​​the bending surface area, the number of stacked layers of the uncoated portion in the winding axis direction of the electrode assembly is 10 or more. The edge of the first and / or second electrode may extend along a winding direction of the wound electrode assembly.

[0026] In a spread-out view (i.e., without wrapping or rolling) of the electrode assembly, optionally the first electrode, the second electrode, and / or the separator may extend between two respective long side ends in the axial direction of the rolled electrode assembly. Optionally, the first electrode, the second electrode, and / or the separator may extend between two respective short side ends in the winding direction (approximately circumferential direction) of the rolled electrode assembly. In some examples, each of the long side ends may be longer than each of the short side ends. Alternatively, the terms long and short may be merely denominations, and each of the short side ends may be longer than the long side ends. Each of the long side ends may be linear, curved, or patterned (e.g., provided with segments as described below), or a combination thereof.

[0027] Additionally or alternatively, the long side end of one of the first and second electrodes and the separator may correspond to a longer or longest side end of one of the plate-shaped first and second electrodes and the separator. For example, for each of the first and second electrodes and the separator that have a substantially rectangular shape before being rolled up to form the electrode assembly of the battery, an edge of the rectangle formed by one of the unrolled first and second electrodes and the separator corresponding to the longer side of the rectangle may correspond to a respective "long side end." The long side end of one of the first and second electrodes and the separator may therefore be perpendicular to a height direction of the battery.In the direction perpendicular to the height of the battery, the uncoated portion of the respective electrode may protrude from and / or extend beyond the separator.

[0028] A bending surface region may be formed adjacent to the edge of the wound electrode. The wound electrode may be provided with the uncoated portion at a side edge relative to the winding axis. The side edge may extend in a spiral relative to the winding axis. The side edge may alternatively be referred to as a long side end. The wound electrode may extend continuously in a spiral cylindrical arrangement around the winding axis. The winding axis may correspond to the central axis of the spiral cylindrical arrangement of the electrode. In the bending surface region, the uncoated portion may be provided, at least in sections, with an inclined orientation relative to the winding axis and / or with a transverse orientation relative to the winding axis.In the bending surface area, the uncoated section can be stacked on itself so that a plurality of winding turns of uncoated sections are each in engagement with one or both adjacent winding turns.

[0029] A partial area of ​​the bending surface region may refer to a circular or annular area. The partial area may extend circularly around the winding axis. The partial area may define an outer diameter and an inner diameter. The inner diameter of the partial area may correspond to the inner diameter of the core. The inner diameter of the partial area may be smaller than the inner diameter of the core. The outer diameter of the partial area may be smaller than the outer circumference. 10 or more, 12 or more, 15 or more, 18 or more, 22 or more, 26 or more, 30 or more, 34 or more layers of the uncoated portion may be stacked in the partial area of ​​the bending surface region in the winding axis direction.10 or more, 12 or more, 15 or more, 18 or more, 22 or more, 26 or more, 30 or more, 34 or more layers of the uncoated portion of adjacent winding turns can form one layer arranged in the partial region in the winding axis direction. In the winding axis direction, the uncoated portion in the partial region can form 10 or more, 12 or more, 15 or more, 18 or more, 22 or more, 26 or more, 30 or more, 34 or more layers stacked on top of each other in the winding axis direction.

[0030] When the number of turns of the first electrode is defined as n1 and a value is defined as a relative radial position R1,k of the turn index k obtained by dividing a turn index k (a natural number from 1 to n1) at a k-th turn location by the number of the total number of turns n1, an aspect ratio of a radial region of R1,k may satisfy a condition that the number of stacked layers of the uncoated portion is 10 or more, particularly 12 or more, or 18 or more, particularly 20 or more, or 22 or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, and / or not more than 95%, not more than 90%, or not more than 85% based on a relative radial position range in which the uncoated portion is bent. The number of stacked layers cannot be greater than the total number of winding turns.In particular, the number of stacked layers of the uncoated section is less than or equal to the total number of winding turns.

[0031] A relative radial position range may be defined by a primary (outer) relative radial position of the winding pitch index and a secondary (inner) relative radial position of the winding pitch index. Radially outside the primary relative radial position, the condition may not be met. Radially inside the secondary relative radial position, the condition may not be met. For example, radially outside the primary relative radial position, the number of stacked layers of the uncoated portion may be less than 10. An aspect ratio may refer to the radial length of the partial region with respect to the radial length of the bending surface region. In particular, an aspect ratio, as used herein, may refer to a ratio of the radial length between the primary and secondary relative radial positions with respect to the radial length of the bending surface region.

[0032] The aspect ratio of the radial range of R1,k that satisfies a condition that the number of stacked layers of the uncoated portion is 10 or more, particularly 12 or more, or 18 or more, particularly 20 or more, or 22 or more, may be 30% to 85%, 40% to 80%, 50% to 75%, or 60% to 70% based on the relative radial position range in which the uncoated portion is bent.

[0033] The second electrode may include an uncoated portion adjacent to an edge of the second electrode (e.g., a long side end thereof) and extending beyond (and / or exposed from) the separator along the winding axis direction of the electrode assembly, adjacent to an edge of the separator (e.g., a long side end thereof). A portion of the uncoated portion may be bent in the radial direction of the electrode assembly, particularly toward the core, to form a bending surface region comprising overlapping layers of the uncoated portion. In a portion of the bending surface region, the number of stacked layers of the uncoated portion in the winding axis direction of the electrode assembly may be 10 or more, particularly 12 or more, or 18 or more, particularly 20 or more, or 22 or more.

[0034] When the number of turns of the second electrode is defined as n2 and a value is defined as a relative radial position R2,k of the turn index k obtained by dividing a turn index k (a natural number from 1 to n2) at a k-th turn location by the number of the total number of turns n2, based on a relative radial position range in which the uncoated portion is bent, an aspect ratio of a radial range of R2,k may satisfy a condition that the number of stacked layers of the uncoated portion is 10 or more, particularly 12 or more, or 18 or more, particularly 20 or more, or 22 or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, and / or not more than 95%, not more than 90%, or not more than 85%.

[0035] The aspect ratio of the radial region of R2,k that satisfies a condition that the number of stacked layers of the uncoated portion is 10 or more may be 30% to 85%, 40% to 80%, 50% to 75%, or 60% to 70% based on the relative radial position range in which the uncoated portion is bent.

[0036] A winding structure may be provided, which may alternatively be referred to as a spiral structure. The first electrode and / or the second electrode may have a respective winding structure. The winding structure may refer to the structure of the first electrode, the second electrode, and / or the separator in a configuration wound around the winding axis. The winding structure may define a core and an outer periphery. The winding structure may comprise a plurality of winding turns. The 1st winding turn of the winding structure may correspond to the core. The winding structure of the first electrode may comprise a number n1 of winding turns. The winding structure of the second electrode may comprise a number n2 of winding turns.The winding structure may extend in the circumferential direction in a spiral manner from an inner terminal winding edge of the first winding turn to an outer terminal winding edge of the n1*-th or n2*-th winding turn, where n1 denotes the number of winding turns of the first electrode and / or where n2 denotes the number of winding turns of the second electrode. In particular, n1 may be equal to n2.

[0037] A relative radial position R1,k refers to a position of a preset k*th winding turn of the first electrode. A relative radial position R2,k refers to a position of a preset k*th winding turn of the second electrode. In the winding structure of the first electrode, the uncoated portion of a region from a relative radial position R1,1 of a 1-th winding turn to a first relative radial position R1,k* of a preset k*th winding turn may have a smaller height than the uncoated portion of a region from a relative radial position R 1,k*+1 of a k*+1-th winding path to a relative radial position 1.

[0038] In the winding structure of the first electrode, the uncoated portion of a region from a relative radial position R1,1 of a 1-th winding turn to a first relative radial position R1,k* of a preset k*th winding turn may have a smaller height than the bending surface region formed by overlapping the bent uncoated portions.

[0039] In the winding structure of the first electrode, the uncoated portion of a region from a relative radial position R1,1 of a 1-th winding turn to a first relative radial position R1,k* of a k*th winding turn may not be bent toward the core of the electrode assembly.

[0040] In the winding structure of the second electrode, the uncoated portion of a region from a relative radial position R2,1 of a 1-th winding turn to a first relative radial position R2,k* of a preset k*th winding turn may have a smaller height than the uncoated portion of a region from a relative radial position R 2,k*+1 of a k*+1-th winding path to a relative radial position 1.

[0041] In the winding structure of the second electrode, the uncoated portion of a range from a relative radial position R2,1 of a 1-th winding turn to a first relative radial position R2,k* of a preset k*th winding turn may have a smaller height than the bending surface area formed by overlapping the bent uncoated portions.

[0042] In the winding structure of the second electrode, the uncoated portion of a region from a relative radial position R2,1 of a 1-th winding turn to a first relative radial position R2,k* of a preset k*th winding turn may not be bent toward the core of the electrode assembly.

[0043] The uncoated portion of the first electrode and / or the second electrode may be divided into a plurality of separate tabs that are independently bendable.

[0044] A separate tab may alternatively be referred to as a segment. Alternatively, a separate tab may be referred to as a separating part or a distinct cut part. One or both of the first and second electrodes may be provided with separate tabs. The separate tabs of the first electrode may be independently bendable. The separate tabs of the second electrode may be independently bendable.

[0045] If both the first electrode and the second electrode are provided with an uncoated portion bent in a radial direction, the uncoated portion of the first electrode may be provided at a first (upper) edge, in particular a first side edge, of the first electrode, and the uncoated portion of the second electrode may be provided at a second (lower) edge, in particular a second side edge, of the second electrode, wherein the first edge and the second edge are arranged opposite one another and / or with respect to the winding axis direction.

[0046] Each of the plurality of separate tabs may have a geometric shape that uses a bend line as a base, and the geometric shape may be formed by connecting one or more straight lines, one or more curves, or a combination thereof. The geometric shape may be symmetrical. The geometric shape may be, for example, a parabola, a triangle, a prism, or another geometric shape.

[0047] A bend line may be in the form of a straight line or an arc. The bend line may extend along the edge of the respective first or second electrode in the winding direction. In particular, the bend line may define an arc length along the edge of the respective first or second electrode in the winding direction. The bend line may separate the respective first or second electrode into a first, generally cylindrically extending spiral or coil portion and a second curved portion in which the overlapping layers of the uncoated portion are stacked on top of each other in the winding axis direction. In the spiral or coil portion, the cross-section of the first or second electrode with respect to the winding axis may be constant in the winding axis direction. In the spiral or coil portion, the first electrode and / or the second electrode may extend generally parallel to the winding axis.In the spiral or coil section, adjacent winding turns of the respective first or second electrode can be separated by the separator in the radial direction. In the bent section, the uncoated section and / or its separate tabs can engage with each other in the winding axis direction. In the bent section, the uncoated section and / or its separate tabs can be aligned at an inclination with respect to the winding axis. The radial direction can be defined as a direction radial with respect to the winding axis.

[0048] The geometric shape may have a width that decreases gradually or continuously from the base to the top. If the uncoated portion is curved in the radial direction, the top may refer to the part closest to the winding axis.

[0049] A lower interior angle of the geometric shape between the base and a side intersecting the base can be 60 degrees to 85 degrees. The lower interior angle can be at least 65 degrees, in particular at least 70 degrees, and / or not more than 80 degrees, in particular not more than 75 degrees. The lower interior angle at the first end of the base can be equal to the lower interior angle at the second end of the base.

[0050] The lower interior angles of the plurality of separate tabs may increase stepwise or continuously along a direction parallel to the winding direction of the electrode assembly. Continuous, as opposed to stepwise, may alternatively be described as gradual.

[0051] Each of the plurality of separate tabs may have a geometric shape having a bend line as a base, and when r is a radius of a winding path in which the separate tab is arranged based on a core center of the electrode assembly, L arc is an arc length of a winding turn corresponding to a lower portion of the separate tab, and θ assumption a lower interior angle of the separate tab assuming that sides of a pair of separate tabs arranged adjacent in the winding path with the radius of r, where an actual lower interior angle θ real of the pair of separate tabs arranged adjacently, the following formula can be satisfied: θreal>θassumption θassumption=90°−360°*(Larc / 2πr)*0.5.

[0052] A circumferential angle equal to the arc length L arc, of the winding pitch corresponding to the lower portion of the separate tab based on the core center of the electrode assembly may be 45 degrees or less. The circumferential angle corresponding to the arc length L arc of the winding pitch corresponding to the lower portion of the separate tab may be 30 degrees or less, 20 degrees or less, or 10 degrees or less. The circumferential angle corresponding to the arc length L arc of the winding pitch corresponding to the lower portion of the separate tab may not be less than 1 degree, not less than 5 degrees, or not less than 10 degrees.

[0053] When an overlap ratio of the separate tabs arranged adjacently in the winding path with the radius of r with respect to the core center of the electrode assembly is calculated using a formula (θ real / θ assumption-1), the overlap ratio of the separate tabs can be greater than 0 and / or equal to or less than 0.05.

[0054] If a virtual circle is drawn passing through a pair of separate tabs arranged adjacently in the winding path with the radius of r with respect to the core center of the electrode assembly, a pair of arcs passing through each separate tab can lie on each other (overlap, contact, be coupled).

[0055] When a ratio of a length of the overlapping arc to a length of the arc passing through each separate tab is defined as an overlap ratio, the overlap ratio of the separate tab may be greater than 0 and / or equal to or less than 0.05.

[0056] In the winding structure of the first electrode, the uncoated portion of a region from a relative radial position R1,1 of a 1-th winding turn to a first relative radial position R1,k* of a k*th winding turn may have a smaller height than the uncoated portion of a region from a relative radial position R 1,k*+1 of a k*+1-th winding path to a relative radial position 1 and not be bent towards the core.

[0057] The height of an uncoated section may refer to the extension of the uncoated section in the direction away from the separator beyond which the uncoated section extends. In particular, the height of an uncoated section before bending may refer to the winding axis direction. In particular, the height of an uncoated section after bending may refer to the distance from the bottom of a tab and / or from the bend line in the direction away from the separator beyond which the uncoated section protrudes.

[0058] A length of the first electrode corresponding to the range from the relative radial position R1,1 to the first relative radial position R1,k* may be 1% to 30%, in relation to a length of the first electrode corresponding to the range from the relative radial position R 1,k*+1 to the relative radial position 1.

[0059] In the winding structure of the first electrode, a bending length fd 1,k*+1 of the uncoated section at a relative radial position R 1,k*+1 of a k*+1-th winding turn must be shorter than a radial length from a relative radial position R1,1 of a 1-th winding turn to a relative radial position R1,k* of a k*th winding turn.

[0060] In the winding structure of the first electrode, when a radius of the core of the electrode assembly is defined as rc, a range from a center of the core to 0.90rc may not be blocked by a bent portion of the uncoated portion located in a range from a relative radial position R 1,k*+1of a k*+1-th winding turn to a relative radial position 1. A region from a center of the core to 0.90rc in the winding axis direction may be free of separate tabs of the first electrode and / or expose the bent uncoated portion of the first electrode.

[0061] A bending length fd 1,k*+1 of the uncoated section at a relative radial position R 1,k*+1 of a k*+1-th winding, the radius rc of the core and a distance d 1,k*+1 from a center of the electrode assembly to the relative radial position R 1,k*+1 can satisfy the following formula: fd1,k*+1+0,90*rc≤d1,k*+1.

[0062] In the winding structure of the second electrode, the uncoated portion of a region from a relative radial position R2,1 of a 1-th winding turn to a first relative radial position R2,k* of a preset k*th winding turn may have a smaller height than the uncoated portion of a region from a relative radial position R 2,k*+1 of a k*+1-th winding path to a relative radial position 1 and not be bent towards the core.

[0063] A length of the second electrode corresponding to the range from the relative radial position R2,1 to the first relative radial position R2,k* may be 1% to 30%, in relation to a length of the second electrode corresponding to the range from the relative radial position R 2,k*+1 to the relative radial position 1.

[0064] In the winding structure of the second electrode, a bending length fd 2,k*+1of the uncoated section at a relative radial position R 2,k*+1 of a k*+1-th winding turn must be shorter than a radial length from a relative radial position R2,1 of a 1-th winding turn to a relative radial position R1,k* of a k*th winding turn.

[0065] In the winding structure of the second electrode, when a radius of the core of the electrode assembly is defined as rc, a range from a center of the core to 0.90rc may not be blocked by a bent portion of the uncoated portion of the second electrode located in a range from a relative radial position R 2,k*+1 of a k*+1-th winding turn to a relative radial position 1. A region from a center of the core to 0.90rc in the winding axis direction may be free of separate tabs of the second electrode and / or expose the bent uncoated portion of the second electrode.

[0066] A bending length fd 2,k*+1 of the uncoated section at a relative radial position R 2,k*+1 of a k*+1-th winding, the radius rc of the core and a distance d 2,k*+1 from a center of the electrode assembly to the relative radial position R 2,k*+1 can satisfy the following formula: fd2,k*+1+0,90*rc≤d2,k*+1.

[0067] In the winding structure of the first electrode, the uncoated portion of a region of a relative radial position R 1,k*+1 of a k*+1-th winding turn to a second relative radial position R1,k@ of a preset k@-th winding turn into a plurality of separate tabs whose heights increase gradually or stepwise along a direction parallel to the winding direction.

[0068] A radial length of the range from the relative radial position R 1,k*+1to the second relative radial position R1,k@ may be 1% to 56% in relation to a radius of the winding structure of the first electrode excluding the core of the electrode assembly.

[0069] In the winding structure of the first electrode, the uncoated portion of a region of a relative radial position R 1,k@+1 a preset k@+1-th winding pitch to a relative radial position 1 into a plurality of separate tabs, and the plurality of separate tabs may have substantially the same height from the relative radial position R 1,k@+1 to the relative radial position 1.

[0070] In the winding structure of the second electrode, the uncoated portion of a region of a relative radial position R 2,k*+1of a k*+1-th winding turn to a second relative radial position R2,k@ of a predetermined k@-th winding turn into a plurality of separate tabs whose heights increase stepwise or gradually along a direction parallel to the winding direction.

[0071] A radial length of the range from the relative radial position R 2,k*+1 to the second relative radial position R2,k@ may be 1% to 56% in relation to a radius of the winding structure of the second electrode excluding the core of the electrode assembly.

[0072] In the winding structure of the second electrode, the uncoated portion of the second electrode may be a region of a relative radial position R 2,k@+1of a k@+1-th winding turn to a relative radial position 1 into a plurality of separate tabs, and the plurality of separate tabs may have substantially the same height from the relative radial position R 2,k@+1 to the relative radial position 1.

[0073] In the winding structure of the first electrode, the uncoated portion bent in the radial direction of the electrode assembly, particularly toward the core, may be divided into a plurality of separate tabs that are independently bendable, and at least a height of the plurality of separate tabs in the winding axis direction and / or a width thereof in the winding direction may increase individually or in groups continuously (gradually) or stepwise along a direction parallel to the winding direction.

[0074] In the winding structure of the second electrode, the uncoated portion bent in the radial direction of the electrode assembly may be divided into a plurality of separate tabs that are independently bendable, and at least a height of the plurality of separate tabs in the winding axis direction and / or a width thereof in the winding direction may increase individually or in groups continuously (gradually) or stepwise along a direction parallel to the winding direction.

[0075] Each of the plurality of separate tabs may satisfy at least one condition including a condition related to a width of 1 mm to 11 mm in the winding direction; a condition related to a height of 2 mm to 10 mm in the winding axis direction; and a condition related to a separation pitch of 0.05 mm to 1 mm in the winding direction.

[0076] A cut groove may be arranged between the plurality of separate tabs, and a predetermined gap may be provided between a bottom of the cut groove and the active material layer of the first electrode or the second electrode. Grooves and tabs may be arranged alternately along the edge in the winding direction. Each pair of tabs immediately adjacent to each other in the winding direction may be separated from each other by a respective groove.

[0077] The gap can have a length of 0.2 mm to 4 mm. In particular, the gap can have a length of at least 0.2 mm, in particular at least 0.5 mm, in particular at least 1 mm. In particular, the gap can have a length of no more than 4 mm, in particular no more than 3 mm, in particular no more than 2 mm.

[0078] The plurality of separate tabs may form a plurality of separate tab groups along the winding direction of the electrode assembly, and separate tabs belonging to the same separate tab group may be substantially the same with respect to at least a width in the winding direction, a height in the winding axis direction, and / or a separation pitch in the winding direction. Separate tab groups, or simply put: tab groups, may define separation tabs of a respective stage if separate tabs vary in stages.

[0079] The separate tabs belonging to the same separate tab group may be configured such that at least the width in the winding direction, the height in the winding axis direction, and / or the separation pitch in the winding direction increases gradually or stepwise along a direction parallel to the winding direction of the electrode assembly.

[0080] At least a portion of the plurality of separate tab groups may be arranged in the same winding path of the electrode assembly.

[0081] The bending surface area formed by the uncoated portion of the first electrode may include a stack number increasing area and a stack number uniform area from the outer periphery of the electrode assembly to the core thereof. The stack number increasing area may be defined as a region where the number of stacked layers of the uncoated portion increases toward the core of the electrode assembly. The stack number uniform area may be defined as a region from a radial position where the increase in the number of stacked layers of the uncoated portion stops to a radial position where the uncoated portion begins to bend.A radial length of the region with a uniform number of stacks may be 30% or more, 40% or more, 50% or more, 60% or more, 70% or more and / or not more than 95%, not more than 90% or not more than 85% in relation to a radial length from a winding turn where the uncoated portion starts to bend to a winding turn where the uncoated portion finishes bending.

[0082] The bending surface area formed by the uncoated portion of the second electrode may include a stack-number-increasing region and a stack-number-uniform region from the outer periphery of the electrode assembly to the core thereof. The stack-number-increasing region may be defined, based on the winding axis, as a region, in particular a circular or annular region, in which the number of stacked layers of the uncoated portion increases toward the core of the electrode assembly. The stack-number-uniform region may be defined, based on the winding axis, as a region, in particular a circular or annular region, from a radial position where the increase in the number of stacked layers of the uncoated portion stops to a radial position where the uncoated portion begins to bend.A radial length of the region with a uniform number of stacks may be 30% or more, 40% or more, 50% or more, 60% or more, 70% or more and / or not more than 95%, not more than 90% or not more than 85% in relation to a radial length from a winding turn where the uncoated portion starts to bend to a winding turn where the uncoated portion finishes bending.

[0083] The first electrode and / or the second electrode may have a thickness of 80 µm to 250 µm. The first electrode and / or the second electrode may have a thickness of at least 100 µm, at least 120 µm, or at least 150 µm, and / or not more than 230 µm, not more than 210 µm, or not more than 200 µm. The interval of the uncoated portions adjacent to winding turns in the radial direction of the electrode assembly may be 200 µm to 500 µm. The interval of uncoated portions located adjacent to winding turns in the radial direction of the electrode assembly may have a thickness of at least 200 µm, at least 250 µm or at least 300 µm and / or not more than 500 µm, not more than 450 µm or not more than 400 µm.

[0084] The uncoated portion of the first electrode may have a thickness of 10 µm to 25 µm, in particular 15 µm to 20 µm.

[0085] The uncoated portion of the second electrode may have a thickness of 5 µm to 20 µm, in particular 10 µm to 15 µm.

[0086] In the partial region of the bending surface region formed by the uncoated section of the first electrode, a total stack thickness of overlapping layers of the uncoated section can be 100 µm to 975 µm, in particular 200 µm to 800 µm, in particular 300 µm to 600 µm.

[0087] The uncoated portion of the first electrode may be divided into a plurality of separate tabs that are independently bendable, wherein the first electrode may include a height-variable region in which heights of separate tabs are variable and a height-uniform region in which heights of separate tabs are uniform, and wherein, in a region formed by bending the separate tabs included in the height-uniform region along the radial direction of the electrode assembly in the bending surface region, a ratio of a stack thickness of the uncoated portion of the bending surface region to the height of the separate tab may be 1.0% to 16.3%.

[0088] In the partial region of the bending surface region formed by the uncoated section of the second electrode, a total stack thickness of overlapping layers of the uncoated section can be 50 µm to 780 µm, in particular 100 µm to 600 µm, in particular 150 µm to 450 µm.

[0089] The uncoated portion of the second electrode may be divided into a plurality of separate tabs that are independently bendable, wherein the second electrode may include a height-variable region in which heights of separate tabs are variable, and a height-uniform region in which heights of separate tabs are uniform, and wherein, in a region formed by bending the separate tabs included in the height-uniform region along the radial direction of the electrode assembly in the bending surface region, a ratio of a stack thickness of the uncoated portion of the bending surface region to the height of the separate tab may be 0.5% to 13.0%,

[0090] Alternatively or additionally, an electrode assembly may be provided in which a first electrode, a second electrode, and a separator arranged therebetween are wound on the basis of an axis to define a core and an outer periphery, wherein the first electrode comprises a first uncoated portion adjacent to an edge of the first electrode (e.g., a long side end thereof) and extends beyond (and / or is exposed from) the separator along a winding axis direction of the electrode assembly, in particular at the edge of the first electrode, and wherein a part of the first uncoated portion is bent in a radial direction of the electrode assembly to form a first bending surface region, and wherein, in a partial region of the first bending surface region, a stack thickness of the first uncoated portion is 100 µm to 975 µm, in particular 200 µm to 800 µm, in particular 300 µm to 600 µm.

[0091] The first uncoated portion of the first electrode may be divided into a plurality of separate tabs that are independently bendable, wherein the first electrode may include a height-variable region in which heights of separate tabs are variable and a height-uniform region in which heights of separate tabs are uniform, and wherein, in a region formed by bending the separate tabs included in the height-uniform region along the radial direction of the electrode assembly in the bending surface region, a ratio of a stack thickness of the uncoated portion of the bending surface region to the height of the separate tab may be 1.0% to 16.3%, in particular 2.0% to 12%, in particular 5% to 10%.

[0092] The second electrode may comprise a second uncoated portion adjacent to an edge of the second electrode (e.g., at a long side end thereof) and extending beyond (and / or exposed from) the separator along the winding axis direction of the electrode assembly, wherein a portion of the second uncoated portion may be bent in the radial direction of the electrode assembly, in particular toward the core, to form a second bending surface region, and wherein, in a portion of the second bending surface region, a stack thickness of the second uncoated portion may be 50 µm to 780 µm, in particular 100 µm to 600 µm, in particular 150 µm to 450 µm.

[0093] The second uncoated portion of the second electrode may be divided into a plurality of separate tabs that are independently bendable, wherein the second electrode may include a height-variable region in which heights of separate tabs are variable and a height-uniform region in which heights of separate tabs are uniform, and wherein, in a region formed by bending the separate tabs included in the height-uniform region along the radial direction of the electrode assembly in the bending surface region, a ratio of a stack thickness of the uncoated portion of the bending surface region to the height of the separate tab may be 0.5% to 13.0%, in particular 1.0% to 10%, in particular 2% to 5%.

[0094] Alternatively or additionally, a battery may be provided comprising: an electrode assembly in which a first electrode, a second electrode, and a separator disposed therebetween are wound on an axis basis to define a core and an outer periphery, wherein at least one of the first electrode and the second electrode includes an uncoated portion adjacent to an edge of the second electrode (e.g., at a long side end thereof) and extending beyond (and / or exposed from) the separator along a winding axis direction of the electrode assembly, particularly at the edge of the first electrode, and at least a portion of the uncoated portion is bent in a radial direction of the electrode assembly to form a bending surface region, and in a partial region of the bending surface region, the number of stacked layers of the uncoated portion is 10 or more;a battery case configured to accommodate the electrode assembly and electrically connected to one of the first electrode and the second electrode to have a first polarity; a sealing body configured to seal an open end of the battery case; a terminal electrically connected to the other of the first electrode and the second electrode to have a second polarity and configured to have an outwardly exposed surface; and a current collector welded to the bending surface region and electrically connected to one of the battery case and the terminal, wherein the welding region of the current collector overlaps the bending surface region in which the number of stacked layers of the uncoated portion is 10 or more.

[0095] The first electrode may include a first uncoated portion adjacent to an edge of the first electrode (e.g., at the long side end thereof) and extending beyond (and / or exposed from) the separator along the winding axis direction of the electrode assembly, particularly at the edge of the first electrode. When the number of turns of the first electrode is defined as n1, and a value obtained by dividing a turn index k (a natural number from 1 to n1) at a k-th turn location by the number of the total number of turns n1 is defined as a relative radial position R1,k of the turn index k, an aspect ratio of a radial area of ​​R1,k that satisfies a condition that the number of stacked layers of the first uncoated portion is 10 or more may be 30% or more, 40% or more, 50% or more, 60% or more, 70% or more and / or not more than 95%,not more than 90% or not more than 85% based on a relative radial position range in which the first uncoated portion is bent.

[0096] The second electrode may include a second uncoated portion adjacent to an edge of the second electrode (e.g., at the long side end thereof) and extending beyond (and / or exposed from) the separator along the winding axis direction of the electrode assembly, and when the number of turns of the second electrode is defined as n2 and a value obtained by dividing a turn index k (a natural number from 1 to n2) at a k-th turn location by the number of the total number of turns n2 is defined as a relative radial position R2,k of the turn index k, an aspect ratio of a radial area of ​​R2,k that satisfies a condition that the number of stacked layers of the second uncoated portion is 10 or more may be 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, and / or not more than 95%,not more than 90% or not more than 85% based on a relative radial position range in which the second uncoated portion is bent.

[0097] The welding area of ​​the current collector can be located on the bending surface area (overlap, contact, be coupled) in which the number of stacked layers of the uncoated portion is 10 or more by 50% or more. The welding area can be located on the bending surface area (overlap, contact, be coupled) in which the number of stacked layers of the uncoated portion is 10 or more, in particular 12 or more, or 18 or more, in particular 20 or more, or 22 or more, by 50% or more, 60% or more, 75% or more.

[0098] The welding area of ​​the pantograph may have a welding strength of 2 kf / cm2 or more, especially 5 kf / cm 2 or more, especially 10 kf / cm 2 or more.

[0099] Alternatively or additionally, a battery may be provided comprising: an electrode assembly in which a first electrode, a second electrode, and a separator disposed therebetween are wound on the basis of an axis to define a core and an outer periphery, wherein the first electrode includes a first uncoated portion adjacent to an edge of the first electrode (e.g., at a long side end thereof) and extends beyond (and / or exposed from) the separator along a winding axis direction of the electrode assembly adjacent to an edge of the separator (e.g., at a long side end thereof), and a portion of the first uncoated portion is bent in a radial direction of the electrode assembly to form a first bending surface region, and in a partial region of the first bending surface region, a stack thickness of the first uncoated portion is 100 µm to 975 µm, a battery case,which is configured to receive the electrode assembly and is electrically connected to one of the first electrode and the second electrode to have a first polarity; a sealing body configured to seal an open end of the battery case; a terminal electrically connected to the other of the first electrode and the second electrode to have a second polarity and configured to have an outwardly exposed surface; and a first current collector welded to the first bending surface region and electrically connected to one of the battery case and the terminal, wherein the welding region of the first current collector overlaps the portion of the first bending surface region in which the stack thickness of the first uncoated portion is 100 µm to 975 µm, in particular 200 µm to 800 µm, in particular 300 µm to 600 µm.

[0100] The first uncoated portion of the first electrode may be divided into a plurality of separate tabs that are independently bendable, wherein the first electrode may include a height-variable region in which heights of separate tabs are variable and a height-uniform region in which heights of separate tabs are uniform, and wherein, in a region formed by bending the separate tabs included in the height-uniform region along the radial direction of the electrode assembly in the first bending surface region, a ratio of a stack thickness of the uncoated portion of the first bending surface region to the height of the separate tab may be 1.0% to 16.3%, in particular 2.0% to 12%, in particular 5% to 10%.

[0101] The welding strength of the first pantograph is in the range of 2 kgf / cm 2 or more, especially 5 kf / cm 2 or more, especially 10 kf / cm2 or more.

[0102] The second electrode may comprise a second uncoated portion adjacent to an edge of the second electrode (e.g., at a long side end thereof) and exposed from the separator along the winding axis direction of the electrode assembly, in particular at the edge of the first electrode, wherein a part of the second uncoated portion may be bent in the radial direction of the electrode assembly, in particular toward the core, to form a second bending surface region.In a partial region of the second bending surface region, a stack thickness of the second uncoated section can be 50 µm to 780 µm, in particular 100 µm to 600 µm, in particular 150 µm to 450 µm, wherein the battery can comprise a second current collector which is welded to the second bending surface region and is electrically connected to one of the battery housing and the terminal, and the welding region of the second current collector can lie on the partial region of the second bending surface region (overlap, contact, be coupled) in which the stack thickness of the second uncoated section is 50 µm to 780 µm, in particular 100 µm to 600 µm, in particular 150 µm to 450 µm.

[0103] The second uncoated portion of the second electrode may be divided into a plurality of separate tabs that are independently bendable, wherein the second electrode may include a height-variable region in which heights of separate tabs are variable and a height-uniform region in which heights of separate tabs are uniform, and wherein, in a region formed by bending the separate tabs included in the height-uniform region along the radial direction of the electrode assembly in the second bending surface region, a ratio of a stack thickness of the uncoated portion of the second bending surface region to the height of the separate tab may be 0.5% to 13.0%, in particular 1.0% to 10%, in particular 2% to 5%.

[0104] The welding strength of the second pantograph is in the range of 2 kgf / cm 2 or more, especially 5 kf / cm 2 or more, especially 10 kf / cm2 or more.

[0105] The welding region of the first current collector can be located (overlapping, contacting, coupled) on the partial region of the first bending surface region in which the stack thickness of the first uncoated section is 100 µm to 975 µm, in particular 200 µm to 800 µm, in particular 300 µm to 600 µm, by 50% or more, in particular 60% or more, in particular 75% or more.

[0106] The welding region of the second current collector can be located (overlapping, contacting, coupled) on the partial region of the second bending surface region in which the stack thickness of the second uncoated section is 50 µm to 780 µm, in particular 100 µm to 600 µm, in particular 150 µm to 450 µm, by 50% or more, in particular 60% or more, in particular 75% or more.

[0107] Alternatively or additionally, a battery pack may be provided comprising at least one or more of the batteries described above and a vehicle comprising at least one or more of the battery packs. BENEFICIAL EFFECTS

[0108] When bending the uncoated portions exposed at both ends of the electrode assembly, the separator or the active material layer can be prevented from being damaged even if the welding performance is increased by sufficiently securing an area where the uncoated portion is overlapped in 10 or more layers in the radial direction of the electrode assembly.

[0109] Since the structure of the uncoated portion adjacent to the core of the electrode assembly is improved, the cavity in the core of the electrode assembly can be prevented from being blocked when the uncoated portion is bent. Thus, the electrolyte injection process and the welding process of the battery case and current collector can be easily performed.

[0110] Since the bending surface area of ​​the uncoated section is welded directly to the current collector instead of a strip-shaped electrode tab, it is possible to provide an electrode assembly with improved energy density and reduced resistance.

[0111] It is possible to provide a battery having a structure that has low internal resistance and improves the welding strength between the current collector and the uncoated portion, and a battery pack and a vehicle including the battery.

[0112] In addition, the present disclosure may have a variety of other effects, and such effects are described in each embodiment, or any description that can be easily derived by a person skilled in the art is omitted for an effect. FIGURE DESCRIPTION

[0113] The accompanying drawings illustrate an embodiment of the present disclosure and, together with the foregoing disclosure, serve to provide a further understanding of the technical features of the present disclosure; consequently, the present disclosure should not be construed as limited to the drawings. Fig. 1 is a plan view showing a structure of an electrode used to manufacture a conventional tabless cylindrical battery. Fig. Figure 2 is a diagram showing an electrode winding process of the conventional tabless cylindrical battery. Fig. 3 is a diagram showing a welding process of a current collector to a bending surface area of ​​an uncoated portion in the conventional tabless cylindrical battery. Fig. 4 is a plan view showing a structure of an electrode. Fig. Figure 5 is a diagram showing the definitions of width, height, and separation pitch of a separate tab. Fig. Figure 6 is a diagram illustrating the conditions regarding the overlap of separate tabs. Fig. 7a and Fig. 7b are diagrams showing an upper cross-sectional structure and a lower cross-sectional structure of an electrode assembly before the bent structure of an uncoated portion is formed. Fig. 8a and Fig. 8b are a sectional view and a perspective view showing an electrode assembly in which the uncoated portion is bent to form a bending surface area. Fig. 9a is a sectional view showing an electrode assembly having a radius of 22 mm included in a cylindrical battery having a form factor of 4680, in which separate tabs of a first electrode are overlapped in a radial direction to form a bending surface region when the separate tabs are bent from the outer circumference to the core without being overlapped in a circumferential direction. Fig. 9b is a sectional view showing an electrode assembly with a radius of 22 mm included in the cylindrical battery with a form factor of 4680, in which the separate tabs of the first electrode are overlapped in the radial direction and in the circumferential direction to form a bending surface region when the separate tabs are bent from the outer circumference to the core while being overlapped in the circumferential direction. Fig. 10 is a sectional view showing a cylindrical battery according to a first embodiment along the Y-axis direction. Fig. 11 is a sectional view showing a cylindrical battery according to a second embodiment along the Y-axis direction. Fig. 12 is a plan view showing a structure of a first current collector. Fig. 13 is a perspective view showing a structure of a second current collector of the present disclosure. Fig. 14 is a plan view showing a state in which a plurality of cylindrical batteries are electrically connected. Fig. 15 is a partially enlarged plan view showing the electrical connection of the plurality of cylindrical batteries of Fig. 14 shows in detail. Fig. 16 is a diagram schematically showing a battery pack including the cylindrical battery. Fig. Figure 17 is a diagram showing a vehicle incorporating the battery pack. EXAMPLES

[0114] Examples are described in detail below with reference to the accompanying drawings. Before proceeding, it should be understood that the terms used in the description and the appended claims should not be construed as limited to generic and literal meanings, but should be interpreted based on the meanings and concepts corresponding to technical aspects of the present disclosure, based on the principle that the inventor is permitted to define terms appropriately for the best explanation.

[0115] Therefore, the description proposed here is merely a preferred example for illustrative purposes only, which is not intended to limit the scope of the disclosure, so that it is understood that other equivalents and modifications could be made thereto without departing from the scope of the disclosure.

[0116] First, an electrode assembly will be described. The electrode assembly is a jelly-roll type electrode assembly in which a first electrode and a second electrode, each having a plate shape and a separator disposed therebetween, are wound around an axle. However, the present invention is not limited to the specific type of electrode assembly, and thus the electrode assembly may have any rolled structure known in the art.

[0117] In particular, at least one of the first electrode and the second electrode comprises an uncoated portion adjacent to an edge of the first electrode (e.g., at a long side end thereof) in the winding direction, which portion is free of active material (i.e., not coated with an active material). At least a portion of the uncoated portion is used per se as an electrode tab.

[0118] Fig. 4 is a plan view showing a structure of an electrode 40.

[0119] With reference to Fig. 4, the electrode 40 includes a current collector 41 made of a metal foil and an active material layer 42. The metal foil may be 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 and includes an uncoated portion 43 adjacent to a side edge of the current collector (e.g., a long side end) in the winding direction X. The uncoated portion 43 is a region not coated with an active material. 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 of it overlaps with the boundary between the active material layer 42 and the uncoated portion 43.The insulating coating layer 44 may comprise a polymer resin and may include an inorganic filler such as Al2O3. The area of ​​the uncoated portion 43 in which the insulating coating layer 44 is formed also corresponds to the uncoated portion 43, since no active material layer 42 is present.

[0120] A bent portion of the uncoated portion 43 of the electrode 40 may include a plurality of separate tabs 61. The plurality of separate tabs 61 may have a height that gradually increases from the core to the outer periphery. The region where the height gradually increases is the remaining area except for the uncoated portion adjacent to the core of the electrode assembly (a core-side uncoated portion A). The core-side uncoated portion A has a relatively lower height than the other portions.

[0121] The separate tab 61 can be formed by laser notching. The separate tab 61 can be formed by a known metal foil cutting process such as ultrasonic cutting or punching.

[0122] When the electrode 40 is wound, each separate tab 61 can be bent in the radial direction of the electrode assembly, for example, toward the core, at a bend line 62. The core refers to the cavity at the winding center of the electrode assembly. Each separate tab 61 has a geometric shape using the bend line 62 as a base. In the geometric shape, the width of a lower portion thereof may be greater than the width of an upper portion thereof. Furthermore, in the geometric shape, the width of the lower portion may gradually or stepwise (not shown) increase toward the upper portion. The geometric shape may have a trapezoidal shape.

[0123] In a modified example, the geometric shape may be formed by connecting one or more straight lines, one or more curves, or a combination thereof. In one example, the geometric shape may be a polygon, such as a triangle, a rectangle, or a parallelogram. In another example, the geometric shape may have an arc shape, such as a semicircle, a semi-ellipse, or the like.

[0124] In order to prevent the active material layer 42 and / or the insulating coating layer 44 from being damaged during bending of the separate tab 61, it is preferable to provide a predetermined gap between the bottom (a portion defined by D4 in Fig. 5) of the cut groove between the separate tabs 61 and the active material layer 42. This is because stress is concentrated near the bottom of the cut groove when the uncoated portion 43 is bent. Specifically, the gap is 0.2 mm to 4 mm. If the gap is set within the appropriate numerical range, the active material layer 42 and / or the insulating coating layer 44 near the bottom of the cut groove can be prevented from being damaged by the stress generated during bending of the separate tab 61. In addition, the gap prevents the active material layer 42 and / or the insulating coating layer 44 from being damaged due to tolerances during notching or cutting of the separate tabs 61.

[0125] The plurality of separate tabs 61 may form a plurality of separate tab groups from the core to the outer periphery. The width, height, and separation pitch of separate tabs belonging to the same separate tab group may be substantially the same.

[0126] Fig. 5 is a diagram showing the definitions of width, height and separation pitch of the separate tab 61.

[0127] With reference to Fig. 5, a cut groove 63 is formed between the separate tabs 61. An edge of the lower portion of the cut groove 63 has a round shape. That is, the cut groove 63 includes a substantially flat bottom portion 63a and a round portion 63c. The round portion 63c connects the bottom portion 63a and the side 63b of the separate tab 61. In a modified example, the bottom portion 63a of the cut groove 63 may be replaced with an arc shape. In this case, the sides 63b of the separate tabs 61 may be smoothly connected by the arc shape of the bottom portion 63a.

[0128] The radius of curvature of the round portion 63c may be greater than 0 and less than or equal to 0.5 mm, particularly greater than 0 and less than or equal to 0.1 mm. The round portion 63c may have a radius of curvature of 0.01 mm to 0.05 mm. When the radius of curvature of the round portion 63c satisfies the above numerical range, cracks can be prevented from occurring in the lower portion of the cut groove 63 while the electrode 40 moves in the winding process or the like.

[0129] The width (D1), height (D2), and separation pitch (D3) of the separate tab 61 are designed to prevent abnormal deformation of the uncoated portion 43 as much as possible, while sufficiently increasing the number of stacked layers of the uncoated portion 43 to prevent the uncoated portion 43 from being torn during bending of the uncoated portion 43 and to improve the welding strength of the uncoated portion 43. Abnormal deformation means that the uncoated portion below the bending point does not maintain a straight state but sinks downward to be irregularly deformed. The bending point may be a point spaced by 2 mm or less, particularly 1 mm or less, from the bottom surface of the cut groove 63 indicated by D4.

[0130] The width (D1) of the separate tab 61 is defined as a length between two points where two straight lines extending from both sides 63b of the separate tab 61 meet a straight line extending from the lower portion 63a of the cut groove 63. The height of the separate tab 61 is defined as the shortest distance between the uppermost side of the separate tab 61 and a straight line extending from the lower portion 63a of the cut groove 63. The separation pitch (D3) of the separate tab 61 is defined as a length between two points where a straight line extending from the lower portion 63a of the cut groove 63 meets straight lines extending from two side walls 63b connected to the lower portion 63a.If the side 63b and / or the lower portion 63a is curved, the straight line may be replaced by a tangent line extending from the side 63b and / or the lower portion 63a.

[0131] The width (D1) of the separate tab 61 can be set in the range of 1 mm to 11 mm. If D1 is less than 1 mm, a non-overlapping area or a void (gap) is generated, thereby insufficiently securing the welding strength when the separate tab 61 is bent toward the core. Meanwhile, if D1 exceeds 11 mm, there is a possibility that the uncoated portion 43 near the bending point (D4) will be torn due to stress when the separate tab 61 is bent. The bending point D4 may be spaced from the lower portion 63a of the cut groove 63. The separation distance may be 2 mm or less, particularly 1 mm or less. In addition, the height of the separate tab 61 can be set in the range of 2 mm to 10 mm.If D2 is less than 2 mm, a non-overlapping area or a void (gap) may be generated when the separate tab 61 is bent toward the core, thereby failing to sufficiently secure the welding strength. Meanwhile, if D2 exceeds 10 mm, it is difficult to manufacture an electrode while uniformly maintaining the flatness of the uncoated portion in the winding direction X. That is, the excess height of the uncoated portion causes a curved surface in the uncoated portion. In addition, the separation pitch (D3) of the separate tab 61 can be set in the range of 0.05 mm to 1 mm. If D3 is less than 0.05 mm, a crack may occur at the uncoated portion 43 near the bottom of the cut groove 63 due to stress when the electrode 40 moves in the winding process or the like.Meanwhile, if D3 exceeds 1 mm, a non-overlapping portion where the separate tabs 61 do not overlap each other or a void (gap) may be generated, which would not ensure sufficient welding strength if the separate tab 61 is bent.

[0132] Meanwhile, when the current collector 41 of the electrode 40 is made of aluminum, it is further preferable to set the separation pitch D3 to 0.5 mm or more. When D3 is 0.5 mm or more, cracks can be prevented from occurring in the lower portion of the cut groove 63 even when the electrode 40 moves at a speed of 100 mm / s or more under a tension of 300 gf or more in the winding process or the like.

[0133] According to the experimental results, when the current collector 41 of the electrode 40 is an aluminum foil with a thickness of 15 μm and D3 is 0.5 mm or more, no cracks occur in the lower portion of the cut groove 63 when the electrode 40 moves under the above moving conditions.

[0134] With further reference to Fig. 4 is the width (d A ) of the core-side uncoated portion A is designed by applying a condition that it does not cover the core of the electrode assembly by 90% or more when the separate tabs 61 are bent toward the core.

[0135] In an example, the width (d A ) of the core-side uncoated section A increases proportionally to the bending length of the separate tab 61 of group 1. The bending length corresponds to the height of the separate tab 61 based on the bending point 62 ( Fig. 4).

[0136] In a specific example, when the electrode 40 is used to manufacture an electrode assembly of a cylindrical battery having a form factor of 4680, the width (d A ) of the core-side uncoated portion A can be adjusted to 180 mm to 350 mm according to the diameter of the core of the electrode assembly.

[0137] The ratio of A / L e the width (d A ) of the core-side uncoated section (A) to the long side length (L e) of the electrode 40 can be from 1% to 30%. In a large cylindrical battery with a diameter of 46 mm, the length of the electrode 40 is quite long, from 3000 mm to 5000 mm, so that the core-side uncoated section (A) can be designed long enough. In cylindrical batteries with a form factor of 1865 or 2170, the electrode length is in the range of 600 mm to 1200 mm. In conventional cylindrical batteries, it is difficult to determine the ratio d A / L e within the above numerical range.

[0138] The width of each separate group of tabs may be designed to form the same winding pitch of the electrode assembly.

[0139] The width of each separate group of tabs may be designed to form a plurality of winding turns of the electrode assembly.

[0140] In a modification, the width and / or height and / or separation pitch of the separate tab 61 belonging to the same separate tab group may be gradually and / or stepwise and / or irregularly increased or decreased within the group or between the groups.

[0141] Groups 1 to 7 are only one example of separate tab groups. The number of groups and the number of separate tabs 61 included in each group can be adjusted to distribute stress as much as possible during the bending process of the uncoated portion 43, to sufficiently ensure the welding strength, to minimize the gap between the sides 63b of the separate tabs 61, and to allow the separate tabs 61 to be overlapped in multiple layers along the radial direction of the electrode assembly without colliding with each other.

[0142] In a modification, separate tabs of some groups can be removed. In this case, the uncoated section in an area from which the separate tabs are removed can have the same height as the core-side uncoated section A.

[0143] The electrode 40 may be divided into a height-variable region in which the height of the separate tab 61 changes along the long side direction, and a height-uniform region in which the height of the separate tab 61 is uniform.

[0144] In the electrode 40, the height-variable region is a region corresponding to groups 1 to 7, and the height-uniform region is a region located near the outer circumference instead of group 7.

[0145] In a specific example, the width (d A) of the core-side uncoated section A can be 180 mm to 350 mm. The width of group 1 can be 35% to 55% of the width of the core-side uncoated section A. The width of group 2 can be 120% to 150% of the width of group 1. The width of group 3 can be 110% to 135% of the width of group 2. The width of group 4 can be 75% to 90% of the width of group 3. The width of group 5 can be 120% to 150% of the width of group 4. The width of group 6 can be 100% to 120% of the width of group 5. The width of group 7 can be 90% to 120% of the width of group 6.

[0146] The reason the widths of groups 1 to 7 do not show a constant increase or decrease pattern is that the width of the separate tab gradually increases from group 1 to group 7, but the number of separate tabs included in the group is limited to integers, and the thickness of the electrode 40 varies along a winding direction X. Accordingly, the number of separate tabs in a specific separate tab group may be reduced. Therefore, the widths of the groups may show an irregular change pattern from the core to the outer circumference, as in the above example.

[0147] Assuming that the width in the winding direction for each of the three separate tab groups consecutively adjacent to each other in the circumferential direction of the electrode assembly is W1, W2, and W3, respectively, it is possible to include a combination of separate tab groups in which W3 / W2 is smaller than W2 / W1.

[0148] In the specific example, groups 4 to 6 correspond to this. The width ratio of group 5 to group 4 is 120% to 150%, and the width ratio of group 6 to group 5 is 100% to 120%, which is less than 120% to 150%.

[0149] In the plurality of separate tabs 61, the lower inner angle (θ) may increase from the core to the outer circumference. The lower inner angle (θ) corresponds to an angle between the straight line passing through the bending line 62 ( Fig. 4) and the straight line (or tangent line) extending from the side 63b of the separate tab 61. If the separate tab 61 is asymmetrical in the left and right directions, the left interior angle and the right interior angle may be different from each other.

[0150] As the radius of the electrode assembly increases, the radius of curvature increases. As the lower inner angle (θ) of the separate tab 61 increases, the stress generated in the radial and circumferential directions when the separate tab 61 is bent can be reduced. Furthermore, as the lower inner angle (θ) increases while the separate tab 61 is bent, the area overlapping with the separate tab 61 on an inner side and the number of stacked layers of the separate tab 61 increase, thereby ensuring uniform welding strength in the radial and circumferential directions and flattening the bending surface area.

[0151] When the angle of the lower inner angle (θ) is adjusted as the radius of the electrode assembly increases when the separate tabs 61 are bent, the separate tabs 61 can be overlapped in the circumferential direction as well as in the radial direction of the electrode assembly.

[0152] Fig. 6 (a) and (b) show an example in which the sides of the separate tabs 61 bent toward the core of the electrode assembly are spaced in parallel in any winding turn with a radius of r with respect to the core center, and an example in which the sides of the bent separate tabs 61 intersect each other.

[0153] With reference to Fig. 6, a pair of separate tabs 61 are arranged adjacent to each other in a winding path with a radius of r relative to the core center O of the electrode assembly. The width and height of the adjacent separate tabs 61 are substantially equal.

[0154] In Fig. 6(a) is the lower interior angle θ assumption an angle assuming that the sides of the separate tab 61 are substantially parallel. The lower interior angle θ assumption is an angle formed by the arc length L arc , which corresponds to the lower portion of the separate tab 61, can be uniquely determined. Meanwhile, θ real an actual lower interior angle when the sides of the adjacent separate tabs 61 intersect each other.

[0155] If the lower interior angles θ assumption and θ real satisfy the following formula 1, the separate tabs 61 arranged in the winding path located at the radius of r with respect to the core center 0 can lie on each other (overlap, contact) in the circumferential direction. θreal>θassumption θassumption=90°−360°*(Larc / 2πr)*0.5 θreal>90°−360°*(Larc / 2πr)*0.5

[0156] Here, r is a radius of the winding path in which the separate tab 61 is arranged, based on the core center of the electrode assembly. L arc is a length of the arc (solid line) corresponding to the lower portion (dotted line) of the separate tab in a circle with a radius of r, and is uniquely determined from the width (D1) of the separate tab 61. 360°*(L arc / 2πr)' is a circumferential angle α of the lower section (dotted line) of the separate tab 61. 360°*(L arc / 2πr)*0.5' is an angle between the separate line flange OB and the separate line flange OA in the right triangle OAB. 90° - 360°*(L arc / 2πr)*0.5' is an angle between the separate line flange OA and the separate line flange AB in the right triangle OAB, which is approximately equal to the lower interior angle (θ assumption ) corresponds to the separate tab 61.

[0157] The circumferential angle α of L arc at any winding pitch radius r can be less than or equal to 45°. If the circumferential angle α exceeds 45°, the separate tab 61 is not easily bent. Therefore, L arc at any radius r greater than 1 mm, which is the lower limit of D1, and has a length of (45 / 360)*(2πr) or less.

[0158] The circumferential angle α may vary depending on a radius (r) of a winding turn where the separate tab 61 is located. In one aspect, the circumferential angle α of the separate tab 61 may gradually or stepwise increase along a radial direction of the electrode assembly within the above numerical range, or vice versa. In another aspect, the circumferential angle α of the separate tab 61 may gradually or stepwise increase and then gradually or stepwise decrease along a radial direction of the electrode assembly within the above numerical range, or vice versa. In another aspect, the circumferential angle α of the separate tab 61 may be substantially the same along a radial direction of the electrode assembly within the above numerical range.

[0159] When a width of each of the plurality of separate tabs 61 varies along a winding direction, the circumferential angle α may be in the range of 45 degrees or less, and the width of each of the plurality of separate tabs 61 may be in the range of 1 mm to 11 mm.

[0160] In an example, if r is 20 mm and the circumferential angle α is 30°, L arc 10.5 mm and θ assumption is approximately 75 degrees. As another example, if r is 25 mm and the circumferential angle α is 25°, L arc 10.9 mm and θ assumption is about 77.5 degrees.

[0161] For each winding radius r, (θ real / θ assumption -1) can be defined as an overlap ratio of the separate tab 61 in the circumferential direction. The overlap ratio of the separate tab 61 is, in particular, greater than 0 and equal to or less than 0.05. θ assumption is the angle formed by the arc L arcat the winding pitch radius r is uniquely determined. If the overlap ratio of the separate tab 61 is greater than 0.05, when the separate tabs 61 are bent, the sides of the separate tabs 61 may collide with each other, and thus the separate tabs 61 cannot be easily bent.

[0162] The degree of overlap of the separate tabs 61 increases proportionally to the overlap ratio. When the separate tabs 61 lie on top of each other (overlap and / or contact) along the circumferential direction of the winding path, the number of stacked layers of the separate tabs 61 can be further increased by bending the separate tabs 61. Embodiments of this will be described later.

[0163] When the electrode 40 is used to manufacture an electrode assembly of a cylindrical battery having a form factor of 4680, the radius of the core is 4 mm, and the height of the separate tab closest to the core is 3 mm, when the radius of the electrode assembly increases from 7 mm to 22 mm, the lower interior angle of the separate tabs 61 may gradually increase in the range of 60° to 85°.

[0164] The radius range and the lower interior angle range can be determined from the form factor and design specifications about the diameter of the core, the height of the separate tab closest to the core, the width (D1) of the separate tab 61 and the overlap ratio.

[0165] Meanwhile, the condition regarding the overlap of the separate tabs can be changed as follows. That is, if a virtual circle is drawn passing through a pair of separate tabs 61 adjacent with respect to the core center O of the electrode assembly 40, as shown in Fig. As shown in Figure 6(b), when an arc e1-e2 and an arc e3-e4 pass through separate tabs that lie on top of each other (overlap and / or contact each other) 61, the pair of adjacent separate tabs may overlap each other. The overlap ratio of the separate tab 61 may be defined as a maximum value for a ratio of the length of the overlapping arc e2-e3 to the length of the arc e1-e2 (or e3-e4) when multiple virtual circles with different radii are drawn. The overlap ratio of the separate tab 61 may be greater than 0 and equal to or less than 0.05.

[0166] The shapes of the separate tabs 60 can be changed differently depending on the location. In one example, a round shape (e.g., semicircle, semiellipse, etc.), which is advantageous for stress distribution, is applied to an area where stress is concentrated, and a polygonal shape (e.g., a rectangle, trapezoid, parallelogram, etc.) with the largest area can be applied to an area where stress is relatively low.

[0167] The separate tab structure may also be applied to the core-side uncoated portion A. However, when the separate tab structure is applied to the core-side uncoated portion A, if the separate tabs are bent according to the radius of curvature of the core, the end of the core-side uncoated portion A may be bent toward the outer periphery, which is called reverse forming. Therefore, the core-side uncoated portion A does not have a separate tab, or even if the separate tab structure is applied to the core-side uncoated portion A, it is desirable to adjust the width and / or height and / or separation pitch of the separate tabs 61 in consideration of the radius of curvature of the core so that reverse forming does not occur.

[0168] The electrode structure of the above embodiments (modifications) can be applied to the first electrode and / or the second electrode having different polarities included in the jelly-roll type electrode assembly. Additionally, 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 can be applied to the other. Additionally, the electrode structures applied to the first electrode and the second electrode may not be identical but may be different from each other.

[0169] 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) can be applied to the first electrode, and the conventional electrode structure (see Fig. 1) can be applied to the second electrode.

[0170] 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.

[0171] 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.

[0172] In one example, the positive electrode active material may comprise an alkali metal compound represented by a general formula A[A x M y]O 2+z (A comprises at least one element selected from Li, Na and K; M comprises 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; x ≥ 0.1 ≤ x + y ≤ 2, 0.1 ≤ z ≤ 2; and the stoichiometric coefficients x, y and z are selected so that the compound maintains electrical neutrality).

[0173] In another example, the active material of the positive electrode may be an alkali metal compound xLiM 1 O2-(1-x)Li2M 2 O3, which is disclosed in US6,677,082, US6,680,143, et al., where M 1 at least one element with an average oxidation state of 3; M 2 at least one element with an average oxidation state of 4; and 0 ≤ x ≤ 1).

[0174] In yet another example, the positive electrode active material may be lithium metal phosphate expressed by a general formula Liam1xfe1xm2yp1ym3zo4z (M 1 comprises at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg and Al; M 2 comprises 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 comprises a halogen element, optionally comprising F; 0 a ≤ 2, 0 ≤ x ≤ 1,0 ≤ y 1,0 ≤ z 1; the stoichiometric coefficients a, x, y and z are selected such that the compound maintains electrical neutrality), or Li3M2(PO4)3 (M comprises at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg and Al).

[0175] The active material of the positive electrode may comprise primary particles and / or secondary particles in which the primary particles are aggregated.

[0176] In one example, the negative electrode active material may use carbon material, lithium metal or a lithium metal compound, silicon or a silicon compound, tin or a tin compound, or the like. Metal oxides such as TiO2 and SnO2 with a potential of less than 2 V can also be used as the negative electrode active material. Low-crystalline carbon, high-crystalline carbon, or the like can be used as the carbon material.

[0177] 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 conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, or the like.

[0178] A coating layer of inorganic particles can be incorporated into at least one surface of the separator. It is also possible for the separator itself to be made from a coating layer of inorganic particles. Particles in the coating layer can be paired with a binder, creating an interstitial volume between adjacent particles.

[0179] The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. As a non-limiting example, the inorganic particles may comprise at least one material selected from the group consisting of Pb(Zr,Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3 (PLZT), PB(Mg3Nb 2 / 3 )O3-PbTiO3 (PMN-PT), BaTiO3, hafnium oxide (HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO and Y2O3.

[0180] The electrode assembly according to the embodiment is a jelly-roll type electrode assembly 80 in which the electrode 40 of the embodiment is applied to a first electrode (positive electrode) and a second electrode (negative electrode). However, the present invention is not limited to specific types of electrode assemblies.

[0181] Fig. 7a and Fig. 7b are drawings showing an upper cross-sectional structure and a lower cross-sectional structure of the electrode assembly 80, respectively, before the bending structures of the uncoated portions 43a, 43a' are formed. In addition, Fig. 8a and Fig. 8b is a cross-sectional view and a perspective view showing the electrode assembly 80 in which the bending surface region F is formed while the uncoated portions 43a, 43a' are bent.

[0182] The electrode assembly 80 can be formed by the method described with reference to Fig. 2. For convenience of description, the protruding structures of the uncoated portions 43a, 43a' extending from the separator are illustrated in detail, and the winding structure of the separator is not shown. The uncoated portion 43a of the electrode assembly 80, which protrudes upward, extends from the first electrode 40. The uncoated portion 43a' of the electrode assembly 80, which protrudes downward, extends from the second electrode 40'. The end of the separator is marked by a dotted line.

[0183] The patterns in which the heights of the uncoated portions 43a, 43a' change are schematically illustrated. That is, the heights of the uncoated portions 43a, 43a' may vary irregularly depending on the position at which the cross section is cut. For example, when the sides of the separate tabs 61 are cut with a trapezoidal shape, the height of the uncoated portion in the cross section is lower than the height (D2 in Fig. 4) of the separate tabs 61. In addition, the uncoated sections 43a, 43a' are not shown at the point where the cut groove 63 ( Fig. 5) is cut.

[0184] The structural features of the uncoated portion 43a of the first electrode 40 will be described in detail below with reference to the drawings. The uncoated portion 43a' of the second electrode 40' may also have substantially the same properties as the uncoated portion 43a of the first electrode 40'.

[0185] With reference to Fig. 7a, Fig. 7b, Fig. 8a and Fig. 8b, the uncoated portions 43a, 43a' of the first electrode 40 and the second electrode 40' are bent in the radial direction to form a bending surface area F. The first electrode 40 and the second electrode 40' are bent toward the core of the electrode assembly 80.

[0186] Assuming that the number of turns of the first electrode 40 is n1 in total, if a value obtained by dividing a turn index k (a natural number from 1 to n1) of a k-th turn by the number of turns of the k-th turn is defined as a relative radial position R1,k of the k-th turn, in the winding structure of the first electrode 40, a radial length of the relative radial position region R1,k in which the number of stacked layers of the uncoated portion 43a is 10 or more is 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, and / or not more than 95%, not more than 90%, or not more than 85% compared to the radial length of turns including the separate tabs.

[0187] For reference, the relative radial position of the 1st winding turn is 1 / n1 because the winding turn is 1. The relative radial position of the kth winding turn is k / n1. The relative radial position of the last n1th winding turn is 1. That is, the relative radial position increases from 1 / n1 to 1 from the core of the electrode assembly 80 to the outer periphery thereof.

[0188] Assuming that the number of turns of the second electrode 40' is n2 in total, if a value obtained by dividing a turn index k (a natural number from 1 to n2) at a k-th turn location by the number of turns in total n2 is defined as a relative radial position R2,k of the k-th turn, in the winding structure of the second electrode 40', a radial length of the relative radial position region R2,k in which the number of stacked layers of the uncoated portion is 10 or more is 30% or more, 40% or more, 50% or more, 60% or more, 70% or more and / or not more than 95%, not more than 90% or not more than 85% compared to the radial length of turns in which the separate tabs are arranged are.

[0189] For reference, the relative radial position of the 1st winding turn is 1 / n2 because the winding turn is 1. The relative radial position of the kth winding turn is k / n2. The relative radial position of the last n2th winding turn is 1. That is, the relative radial position increases from 1 / n2 to 1 from the core of the electrode assembly 80 to the outer periphery thereof.

[0190] The winding pitch indices k of the first electrode 40 and the second electrode 40' should be understood as variables to which different values ​​can be assigned.

[0191] When the uncoated portions 43a, 43a' are bent in the radial direction, the bending surface areas F are formed on the upper and lower portions of the electrode assembly 80, as shown in Fig. 8a and Fig. 8b shown.

[0192] With reference to Fig. 8a and Fig. 8b, a plurality of separate tabs 61 are overlapped in multiple layers along the radial direction while being bent toward the core C of the electrode assembly 80.

[0193] The number of stacked layers of the separate tabs 61 may be defined as the number of separate tabs 61 that intersect an imaginary line when the imaginary line is drawn in the winding axis direction (Y) at any radial point on the bending surface area F.

[0194] The number of stacked layers of the separate tabs 61 may be 10 or more in a radius range of at least 30%, 40% or more, 50% or more, 60% or more, 70% or more and / or not more than 95%, not more than 90% or not more than 85% based on the radial length (R1) of the winding turns including the separate tabs 61, in order to sufficiently increase the welding strength between the bending surface region F and the current collector and to prevent the separator and the active material layer from being damaged during the welding process.

[0195] The current collector can be laser-welded to the bending surface area F of the uncoated portion 43a, 43a'. Alternatively, other known welding techniques, such as resistance welding, can be used. When laser welding is used, it is desirable to increase the laser power to sufficiently ensure weld strength. If the laser power is increased, the laser could penetrate the electrode assembly 80 through the overlapping areas of the uncoated portions 43a, 43a', which could damage the separator and the active material layer. Therefore, to prevent laser penetration, it is preferable to increase the number of stacked layers of the uncoated portions 43a, 43a' in the welding area to a certain level or more. To increase the number of stacked layers of the uncoated portions 43a, 43a', the height of the separate tabs 61 must be increased.However, if the height of the separate tabs 61 is increased, the uncoated portions 43a, 43a' may be warped during the manufacturing process of the electrode 40. Therefore, it is desirable to set the height of the separate tabs 61 to a suitable level, particularly 2 mm to 10 mm.

[0196] When the radius range where the number of stacked layers of the separate tabs 61 is 10 or more is designed to be 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, and / or not more than 95%, not more than 90%, or not more than 85% compared to R1 in the bending surface area F, and the area where the separate tabs 61 are overlapped in 10 or more layers is laser welded to the current collector, even though the power of the laser is increased, the overlapping portion of the uncoated portion sufficiently masks the laser to prevent the separator and the active material layer from being damaged by the laser. In addition, since the number of stacked layers of the separate tabs 61 is large in the area where the laser is irradiated, weld beads with sufficient volume and thickness are formed.Accordingly, the welding strength can be sufficiently secured and the resistance of the welding interface can also be reduced.

[0197] When welding the current collector, the laser power can be determined by the desired weld strength between the bending surface area F and the current collector. The weld strength increases proportionally to the number of stacked layers of the uncoated sections 43a, 43a'. This is because, as the number of stacked layers of the uncoated sections 43a, 43a' increases, the volume of the weld beads formed by the laser increases.

[0198] The welding strength can reach 2 kgf / cm 2 or more, especially 4 kgf / cm 2or more. When the weld strength satisfies the above numerical range, the properties of the weld interface do not deteriorate even when strong vibrations act on the electrode assembly 80 along the winding axis direction and / or the radial direction, and the volume of the weld beads is sufficient to reduce the resistance of the weld interface. The laser power for realizing the above weld strength condition varies depending on the laser equipment and can be appropriately set in the range of 250 W to 320 W or in the range of 40% to 100% of the maximum laser power specification.

[0199] The welding strength can be expressed as a tensile force per unit area (kgf / cm 2) of the current collector when the current collector begins to detach from the bending surface area F. Specifically, after the current collector is completely welded, a tensile force is applied to the current collector, gradually increasing the magnitude of the tensile force. As the tensile force increases, the uncoated portions 43a, 43a' begin to detach from the welding interface. At this time, the weld strength is the value obtained by dividing the tensile force acting on the current collector by the area of ​​the current collector.

[0200] The first electrode 40 may include a current collector (foil) 41 and an active material coating layer 42 formed on at least one surface of the current collector 41. Here, the current collector 41 may have a thickness of 10 µm to 25 µm, and an interval between adjacent winding turns in a radial direction of the electrode assembly 80 may be 200 µm to 500 µm. The current collector 41 may be formed of aluminum.

[0201] The second electrode 40' may include a current collector (foil) and an active material coating layer formed on at least one surface of the current collector. Here, the current collector may have a thickness of 5 µm to 20 µm, and an interval between adjacent winding turns in the radial direction of the electrode assembly 80 may be 200 µm to 500 µm. The current collector may be formed of copper.

[0202] With reference to Fig. 4, Fig. 7a and Fig. 7b, in the winding structure of the first electrode 40, the uncoated portion of the area from the relative radial position R1,1 of the first electrode 40 to a preset first relative radial position R1,k* may have a smaller height than the uncoated portion of the area from a relative radial position R 1,k*+1 of a k*+1-th winding turn to a relative radial position 1. The height of the uncoated section of the area from the relative radial position R1,1 to the preset first relative radial position R1,k* corresponds to the height of the uncoated section of the core-side uncoated section A (see Fig. 4).

[0203] In the winding structure of the first electrode 40, the uncoated portion of the area from the relative radial position R1,1 to the first relative radial position R1,k* may have a smaller height than the bending surface area F formed by overlapping the bent uncoated portions.

[0204] In the winding structure of the first electrode 40, the uncoated portion of the area from the relative radial position R1,1 to the first relative radial position R1,k* may not be bent toward the core of the electrode assembly 80.

[0205] Similar to the first electrode 40, in the winding structure of the second electrode 40', the uncoated portion of the area from the relative radial position R2,1 to the preset first relative radial position R2,k* may have a smaller height than the uncoated portion of the area from the relative radial position R 2,k*+1of the k*+1-th winding path to the relative radial position 1.

[0206] In addition, in the range from the relative radial position R2,1 to the preset first relative radial position R2,k*, the uncoated portion may have a smaller height than the bending surface area F formed by overlapping the bent uncoated portions.

[0207] The uncoated portion of the region from the relative radial position R2,1 to the first relative radial position R2,k* cannot be bent towards the core of the electrode assembly.

[0208] In the winding structure of the second electrode 40', the uncoated portion of the area from the relative radial position R2,1 to the first relative radial position R2,k* may have a smaller height than the uncoated portion of the area from the relative radial position R 2,k*+1to the relative radial position 1 and cannot be bent towards the core.

[0209] In the winding structure of the first electrode 40, the bending length fd 1,k*+1 of the uncoated section of the relative radial position R 1,k*+1 shorter than the radial length from the relative radial position R1,1 to the relative radial position R1,k*. Therefore, the core C of the electrode assembly 80 cannot be blocked by the bending part of the uncoated portion 43a located in the range from the relative radial position R 1,k*+1 to the relative radial position 1.

[0210] Alternatively, the core C of the electrode assembly 80 may not be blocked by the bent portion of the uncoated portion 43a located in the range from the relative radial position R 1,k*+1 to the relative radial position 1 by 90% or more based on its radius (r c) of it. That is, a radial region of the core C that is at least 0 to 0.9 r c cannot be blocked by the bent portion of the uncoated portion 43a.

[0211] The bending length fd 1,k*+1 of the uncoated section 43a located at the relative radial position R1,k*+1, the radius (r c ) of the core and the distance (d 1,k*+1 ) from the center of the core C to the relative radial position R 1,k*+1 can satisfy the following formula 2. fd1,k*+1+0,9*rc≤d1,k*+1

[0212] In the winding structure of the second electrode 40', the uncoated portion of the area from the relative radial position R2,1 to the first relative radial position R2,k* may have a smaller height than the uncoated portion of the area from the relative radial position R 2,k*+1 to the relative radial position 1 and cannot be bent towards the core.

[0213] In the winding structure of the second electrode 40', the bending length fd 2,k*+1 of the uncoated section located at the relative radial position R 2,k*+1 be shorter than the length from the relative radial position R2,1 to the first relative radial position R2,k*. Therefore, the core C of the electrode assembly 80 cannot be blocked by the bending part of the uncoated portion located in the range from the relative radial position R 2,k*+1 to the relative radial position 1.

[0214] Alternatively, the core C of the electrode assembly 80 may not be blocked by the bent portion of the uncoated portion 43a' located at the relative radial position R 2,k*+1 by 90% or more based on its radius (r c ) is located.

[0215] The bending length fd 2,k*+1 of the uncoated section 43a', which is located at the relative radial position R2,k*+1 is located, the radius (r c ) of the core and the distance (d 2,k*+1 ) from the center of the core C to the relative radial position R 2,k*+1 can satisfy the following formula 3. fd2,k*+1+0,9*rc≤d2,k*+1

[0216] In the winding structure of the first electrode 40, the uncoated portion of the second electrode 40' is separated from a second relative radial position R 1,k@+1 of the preset k@+1-th winding pitch to the relative radial position 1 into a plurality of separate tabs 61, and the height of the plurality of separate tabs 61 can be varied from the relative radial position R 1,k@+1 to the relative radial position 1 be essentially the same.

[0217] Meanwhile, in the winding structure of the first electrode 40, the uncoated portion 43a of a region from the relative radial position R 1,k*+1to the second relative radial position R1,k@ of a preset k@-th winding pitch into a plurality of separate tabs 61, the heights of which can increase stepwise or gradually towards the outer circumference. Therefore, the range from the relative radial position R 1,k*+1 to the relative radial position R1,k@ the height-variable area.

[0218] For example, in the winding structure of the first electrode 40 with a radius of 22 mm, if the radial length of the height-variable region of the separate tab is defined as H1 and the ratio of H1 to the radius (R- r c ) of the winding structure of the first electrode 40 except for the core C as a height-variable area ratio (H1 / (Rr c )), the ratio of the height variable area can be calculated as follows by rounding to zero decimal place.

[0219] In example 1, R can be 22 mm, the core radius (r c) can be 5 mm and R- r c can be 17 mm. The height of the separate tab 61 can be adjusted in 8 steps from 2 mm to 10 mm within a radius range of 7 mm to 15 mm. After the radius of 15 mm, the height of the separate tab 61 is maintained at 10 mm. Since H1 is 8 mm, the ratio of the height-adjustable range can be 47% (8 mm / 17 mm).

[0220] In Example 2, R and r c The same as in Example 1. The height of the separate tab 61 can be changed in 7 steps from 2 mm to 9 mm within the radius range from 7 mm to 14 mm. After the radius of 14 mm, the height of the separate tab 61 is maintained at 9 mm. Since H1 is 7 mm, the ratio of the height-variable range can be 41% (7 mm / 17 mm).

[0221] In Example 3, R and r cThe same as in Example 1. The height of the separate tab 61 can be changed in 6 steps from 2 mm to 8 mm within the radius range from 7 mm to 13 mm. After the radius of 13 mm, the height of the separate tab 61 is maintained at 8 mm. Since H1 is 6 mm, the ratio of the height-variable range can be 35% (6 mm / 17 mm).

[0222] In Example 4, R and r c The same as in Example 1. The height of the separate tab 61 can be changed in 5 steps from 2 mm to 7 mm within the radius range from 7 mm to 12 mm. After the radius of 12 mm, the height of the separate tab 61 is maintained at 7 mm. Since H1 is 5 mm, the ratio of the height-variable range can be 29% (5 mm / 17 mm).

[0223] In Example 5, R and r cThe same as in Example 1. The height of the separate tab 61 can be changed in 4 steps from 2 mm to 6 mm within the radius range from 7 mm to 11 mm. After the radius of 11 mm, the height of the separate tab 61 is maintained at 6 mm. Since H1 is 4 mm, the ratio of the height-variable range can be 24% (4 mm / 17 mm).

[0224] In Example 6, R and r c The same as in Example 1. The height of the separate tab 61 can be changed in 3 steps from 2 mm to 5 mm within the radius range from 7 mm to 10 mm. After the radius of 10 mm, the height of the separate tab 61 is maintained at 5 mm. Since H1 is 3 mm, the ratio of the height-variable range can be 18% (3 mm / 17 mm).

[0225] In Example 7, R and r cThe same as in Example 1. The height of the separate tab 61 can be changed in two steps from 2 mm to 4 mm within the radius range from 7 mm to 9 mm. After the radius of 9 mm, the height of the separate tab 61 is maintained at 4 mm. Since H1 is 2 mm, the ratio of the height-variable range can be 12% (2 mm / 17 mm).

[0226] In Example 8, R and r c The same as in Example 1. The height of the separate tab 61 can be changed in one step from 2 mm to 3 mm within the radius range from 7 mm to 8 mm. After the radius of 8 mm, the height of the separate tab 61 is maintained at 3 mm. Since H1 is 1 mm, the ratio of the height-variable range can be 6% (1 mm / 17 mm).

[0227] In summary, if R is 22 mm and r c5 mm, if the height of the separate tab changes in the radius range from 7 mm to 15 mm in the range from 2 mm to 10 mm in one of one to eight steps, the ratio of the height variable range is 6% to 47%.

[0228] The numerical range of the ratio of the height variable area can be adjusted according to the size of the radius (r c ) of the core C. Since the calculation method is similar to the above, only the results are disclosed.

[0229] In an example, if R is 22 mm and r c 4 mm, if the height of the separate tab in the radius range from 6 mm to 14 mm changes gradually in the range from 2 mm to 10 mm in one of one to eight steps, the ratio of the height variable range can be 6% to 44%.

[0230] In another example, if R is 22 mm and r c3 mm, if the height of the separate tab in the radius range from 5 mm to 13 mm changes gradually in the range from 2 mm to 10 mm in one of one to eight steps, the ratio of the height variable range is 5% to 42%.

[0231] In yet another example, if R is 22 mm and r c 2 mm, if the height of the separate tab in the radius range from 4 mm to 12 mm changes gradually in the range from 2 mm to 10 mm in one of one to eight steps, the ratio of the height variable range is 5% to 40%.

[0232] From the calculation examples above, if the radius (r c ) of the core C is changed in the range from 2 mm to 5 mm, the ratio of the height variable range is 5% to 47%. When the radius of the electrode assembly 80 is constant, the lower and upper limits of the ratio of the height variable range decrease accordingly when the radius (r c) of the nucleus C decreases.

[0233] Meanwhile, the upper and lower limits of the ratio of the height variable range can be changed by the height change amount of the separate tab 61 per 1 mm radius increase and the number of height changes.

[0234] In an example, if the height of the separate tab 61 changes by 0.2 mm per 1 mm radius increase, the lower and upper limits of the ratio of the height variable range are 1% and 9%, respectively.

[0235] In another example, if the height of the separate tab 61 changes by 1.2 mm per 1 mm radius increase, the lower and upper limits of the ratio of the height variable range are 6% and 56%, respectively.

[0236] Specifically, among the above examples, the ratio of the height-variable range is 1% to 56%. When the ratio of the height-variable range of the separate tab 61 satisfies the above numerical range, the ratio of the relative radial positions where the number of stacked layers of the uncoated portion 40 is 10 or more can be at least 30% of the radial length (R1) of the winding turns including the separate tab 61. As described later, this configuration provides beneficial effects in terms of the welding strength and resistance of the current collector.

[0237] With further reference to Fig. 4 and Fig. 7b, in the winding structure of the second electrode 40', the uncoated portion of the area from the relative radial position R 2,k*+1to a second relative radial position R2,k@ of the predetermined k@-th winding pitch, also divided into a plurality of separate tabs 61, wherein the height of the plurality of separate tabs 61 can increase stepwise or progressively towards the outer circumference. Therefore, the range from the relative radial position R 2,k*+1 to the relative radial position R2,k@ the height-variable area.

[0238] If in the winding structure of the second electrode 40' the radial length of the height-variable region is defined as H2 and the ratio of H2 to the radius (R- r c ) of the winding structure of the second electrode 40' except for the core C as the ratio of the height variable area (H2 / (R- r c )), the ratio of the height variable area as the first electrode is in particular 1% to 56%.

[0239] When the ratio of the height variable range for the separate tab 61 of the uncoated portion 43a' satisfies the above numerical range, the ratio of the radial length of the relative radial positions at which the number of stacked layers of the uncoated portion 40 is 10 or more compared to the radial length (R2) of the winding turns including the separate tab 61 may be at least 30%.

[0240] In the winding structure of the second electrode 40', the uncoated portion of the second electrode 40' is separated from the second relative radial position R 2,k@+1 of the preset k@+1-th winding pitch to the relative radial position 1 into a plurality of separate tabs 61, and the height of the plurality of separate tabs 61 can be varied from the relative radial position R 2,k@+1 to the relative radial position 1 be essentially equal.

[0241] In the winding structure of the first electrode 40, the uncoated portion 43a bent toward the core is divided into a plurality of separate tabs 61, and at least a height in a winding axis direction and / or a width in the winding direction of the plurality of separate tabs 61 may gradually or stepwise increase from the core toward the outer circumference individually or in groups.

[0242] Similarly, in the winding structure of the second electrode 40', the uncoated portion 43a' bent toward the core is divided into a plurality of separate tabs 61, and at least a height in the winding axis direction and / or a width in the winding direction of the plurality of separate tabs 61 may gradually or stepwise increase from the core toward the outer circumference individually or in groups.

[0243] When the bending part of the uncoated sections 43a, 43a' is divided into a plurality of separate tabs 61, each of the plurality of separate tabs 61 may satisfy at least one condition comprising a width (D1 in Fig. 5) condition from 1 mm to 11 mm in the winding direction; one on a height (D2 in Fig. 5) a condition related to a separation pitch (D3) of 2 mm to 10 mm in the winding axis direction; and a condition related to a separation pitch (D3) of 0.05 mm to 1 mm in the winding direction.

[0244] A predetermined gap may be formed between the bottom portion of the cut groove of the separate tab 61 (a portion defined by D4 in Fig. 5) and the active material layer 42. The gap can be 0.2 mm to 4 mm.

[0245] With reference to Fig. 4, when the bending part of the uncoated portions 43a, 43a' is divided into a plurality of separate tabs 61, the plurality of separate tabs 61 may form a plurality of separate tab groups from the core to the outer periphery, and separate tabs belonging to the same separate tab group may be equal with respect to at least a width in the winding direction, a height in the winding axis direction, and / or a separation pitch in the winding direction.

[0246] At least a portion of the plurality of separate tab groups may be arranged in the same winding turn of the electrode assembly 80. In one example, the separate tabs included in each group may form at least one winding turn in the winding structure of the electrode assembly 80. In another example, the separate tabs included in each group may form two or more winding turns in the winding structure of the electrode assembly 80.

[0247] Fig. 9a is a partial sectional view showing an electrode assembly with a radius of 22 mm included in a cylindrical battery with a form factor of 4680, wherein the uncoated portion 43a of the first electrode 40, which is divided into a plurality of separate tabs 61, is bent from the outer circumference to the core to form a bending surface region F, in a part of the bending surface region F, the uncoated portion 43a is overlapped in 10 or more layers along the radial direction, and the increasing stack number region and the uniform stack number region appear along the radial direction of the electrode assembly 80.

[0248] With reference to Fig. 9a, the number of stacked layers of the uncoated portion 43a in the bending surface area F sequentially increases from the outer periphery of the electrode assembly 80 toward the core and reaches a maximum value, and the maximum value is kept in a predetermined radius range and then decreases by 1 or 2 in the vicinity of the core.

[0249] Hereinafter, the radius range in which the number of stacked layers of the uncoated portion 43a sequentially increases to the maximum value from the outer periphery of the electrode assembly 80 toward the core is defined as the stack number increasing range, and the range in which the number of stacked layers of the uncoated portion 43a is maintained at the maximum value and the remaining range near the core are collectively defined as the uniform stack number range. Since the uniform stack number range includes the range in which the number of stacked layers of the uncoated portion 43a is maintained at the maximum value, the bending surface range F is flatter than the other ranges, which corresponds to an optimal welding range.

[0250] In Fig. 9a, the uncoated section 43a is divided into separate tabs of a trapezoidal shape, as in Fig. 5, and only the upper portion of the uncoated portion 43a is shown based on the lower portion 63a of the cut groove 63. The uncoated portion 43a is not shown in a section corresponding to the cross section of the cut groove 63.

[0251] The points where the separate tabs 61 are actually bent are not exactly the same and are spaced from the lower end of the cut groove 63 by a predetermined distance. As the number of stacked layers of the uncoated portion 43a increases toward the core, resistance to overlapping occurs, so it is preferable to perform bending at a point spaced from the lower end of the cut groove 63 by a predetermined distance. The separation distance is 2 mm or less, particularly 1 mm or less. When there is a separation distance, the separate tabs 61 overlap each other better in the radial direction.

[0252] The bending surface area F is formed when the separate tabs located at different winding turns overlap in the radial direction of the electrode assembly 80. As shown in Fig. 9a, the separate tabs 61 do not overlap in the circumferential direction. This means that there is a gap between the sides of the separate tabs 61, as shown in Fig. 6(a). The gap condition can be satisfied by adjusting the width, height, separation pitch, bottom inner angle, or the like of the separate tabs. The bending surface area F when the separate tabs overlap in the circumferential direction will be described later with reference to Fig. 9b.

[0253] The radius (r c) of the core of the electrode assembly 80 is 4 mm. The height of the separate tab also starts at 3 mm. There is no separate tab in the uncoated section 43a from 4 mm to 7 mm based on the radius of the electrode assembly. That is, separate tabs are present in the area with a radius of 7 mm to 22 mm among the total radius of 22 mm of the electrode assembly, and the width of the radius area where the separate tab 61 is present is 15 mm. If the core is deformed by the separate tab by a maximum of 10% based on the radius (r c ) of the core, the location where separate tabs begin to be arranged may be offset toward the core.

[0254] The winding structure features a separate tab with a height of 3 mm from the winding pitch and a radius of approximately 7 mm. The height of the separate tab increases from the 7 mm radius of the winding structure by 1 mm for every 1 mm radius increase from the core to the outer circumference. The height increment period of the separate tab can be varied within a range of 0.2 mm to 1.2 mm per unit radius (1 mm).

[0255] Fig. Figure 9a-(a) shows a case where the maximum height of the separate tab is 8 mm. In this case, the separate tab is positioned from the point where the radius of the electrode assembly becomes 7 mm from the core center. Only when the separate tab is bent toward the core with a height of 3 mm does the separate tab not cover the core with a radius of 4 mm. The height of the separate tab increases in five steps from 3 mm to 8 mm as the radius increases from 7 mm to 12 mm. Furthermore, the height of the separate tab is kept at 8 mm from 12 mm to 22 mm in radius. The height-variable range of the separate tab is in the radius range of 7 mm to 12 mm, and the ratio of the height-variable range is 28% (5 / 18, rounded to zero decimal place; this will be applied identically below).

[0256] Fig. Figure 9a-(b) shows a case where the maximum height of the separate tab is 7 mm. Also, in this case, the separate tab is positioned from the position where the radius of the electrode assembly becomes 7 mm from the core center. Only when the separate tab is bent toward the core with a height of 3 mm does the separate tab not cover the core with a radius of 4 mm. The height of the separate tab increases in four steps from 3 mm to 7 mm as the radius increases from 7 mm to 11 mm. Furthermore, the height of the separate tab is kept at 7 mm from 11 mm to 22 mm in radius. The height-variable range of the separate tab is within the radius range of 7 mm to 11 mm, and the height-variable range ratio is 22% (4 / 18).

[0257] Fig. Figure 9a-(c) shows a case where the maximum height of the separate tab is 6 mm. Also, in this case, the separate tab is positioned from the position where the radius of the electrode assembly becomes 7 mm from the core center. Only when the separate tab is bent toward the core with a height of 3 mm does the separate tab not cover the core with a radius of 4 mm. The height of the separate tab increases in three steps from 3 mm to 6 mm as the radius increases from 7 mm to 10 mm. Furthermore, the height of the separate tab is kept at 6 mm from 10 mm to 22 mm in radius. The height-variable range of the separate tab is within the radius range of 7 mm to 10 mm, and the height-variable range ratio is 17% (3 / 18).

[0258] As in (a), (b) and (c) of Fig. As shown in Figure 9a, the height-variable range of the separate tab can start at a radius of 7 mm. Furthermore, the ratio of the height-variable range is 17% to 28%. This ratio range is included in the range of 1% to 56% described above.

[0259] With reference to Fig. 9a, the number of stacked layers of the uncoated portion 43a increases sequentially from the outer periphery to the core. Furthermore, it can be seen that although the minimum length of the separate tab is 3 mm, the maximum value of the number of stacked layers increases to 12, 15, and 18 as the maximum length of the separate tab increases to 6 mm, 7 mm, and 8 mm. Furthermore, the thickness of the bending surface region F increases proportionally according to the number of stacked layers.

[0260] For example, if the maximum height of the separate tab is 8 mm, the number of stacked layers of the uncoated portion 43a increases to 18 in the radius range of 7 mm from the outer circumference of the electrode assembly 80 toward the core, and in the radius range of 8 mm toward the core from the radial point where the increase in the number of stacked layers stops, the number of stacked layers of the uncoated portion 43a is uniformly maintained at the level of 18. In this example, in the uniform stacking number region, the number of stacked layers is at least 16, and its radial width is 8 mm. The width of the uniform stacking number region compared to the radial length (15 mm) of the winding turns including the separate tab is 53% (8 / 15, rounded to zero decimal place; this will be applied identically below).

[0261] As another example, when the maximum height of the separate tab is 7 mm, the number of stacked layers of the uncoated portion 43 a increases up to 15 in the radius range of 6 mm from the outer circumference of the electrode assembly 80 toward the core, and in the radius range of 9 mm toward the core from the radial position where the increase in the number of stacked layers stops, the number of stacked layers of the uncoated portion 43 a is uniformly maintained at the level of 15. Therefore, the radial width of the uniform stacking number region is 9 mm, and the number of stacked layers in the uniform stacking number region is at least 13. The width of the uniform stacking number region compared to the radial length (15 mm) of the winding turns including the separate tab is 60% (9 / 15).

[0262] As another example, when the maximum height of the separate tab is 6 mm, the number of stacked layers of the uncoated portion 43 a increases up to 12 in the radius range of 5 mm from the outer circumference of the electrode assembly 80 toward the core, and in the radius range of 10 mm toward the core from the radial position where the increase in the number of stacked layers stops, the number of stacked layers of the uncoated portion 43 a is uniformly maintained at the level of 12. Therefore, the radial width of the uniform stacking number region is 10 mm, and the number of stacked layers in the uniform stacking number region is at least 11. The width of the uniform stacking number region compared to the radial length (15 mm) of the winding turns including the separate tab is 67% (10 / 15).

[0263] It is understood that when the minimum length of the separate tab is 3 mm and the maximum length of the separate tab is 6 mm, 7 mm, and 8 mm, the length of the stacking number increasing region in which the number of stacked layers gradually increases is increased to 5 mm, 6 mm, and 7 mm, respectively, and the ratio of the uniform stacking number region in which the number of stacked layers of the uncoated portion 43a is 10 or more is 53% to 67%.

[0264] Meanwhile, the thickness of the bending surface region F increases proportionally to the number of stacked layers of the uncoated portion 43a. Depending on the minimum height and the maximum height of the separate tab in the height-variable region, the number of stacked layers of the uncoated portion 43a can be reduced to 10, and thus the number of stacked layers of the uncoated portion 43a can be 10 to 18. In one example, if the uncoated portion 43a is aluminum and its thickness is 10 µm to 25 µm, the thickness of the bending surface region F can be 100 µm to 450 µm. In another example, if the uncoated portion 43a is copper and its thickness is 5 µm to 20 µm, the thickness of the bending surface region F can be 50 µm to 360 µm.When the thickness of the bending surface region F satisfies the condition of the above numerical range, when the current collector is welded to the bending surface region F using a laser, the bending surface region F sufficiently absorbs the laser energy. As a result, weld beads are formed in a sufficient volume on the bending surface region F to increase the welding strength. In addition, the separator or the like located under the bending surface region F can be prevented from being damaged because the welding portion is perforated by the laser.

[0265] The current collector may be welded to the bending surface area F. The welding area of ​​the current collector may be at least partially located within (overlapping and / or associated with) the uniform range of the stack number based on the radial direction.

[0266] 50% to 100% of the current collector welding area can be located (overlapped and / or associated with) the uniform range of the stack number in the radial direction of the electrode arrangement. As the overlap ratio of the welding area increases, it is preferable to improve weld strength and increase the volume of weld beads. In the current collector welding area, the remaining area that does not overlap with the uniform range of the stack number can be located (overlapped and / or associated with) the increasing range of the stack number.

[0267] Meanwhile, as mentioned with reference to Fig. 6, when the separate tabs 61 of the uncoated portion 43a are bent to form the bending surface area F, if the lower interior angle of the separate tab included in each separate tab group satisfies the condition of Formula 1, adjacent separate tabs 61 located on the same winding turn are in contact with each other (overlapping, contacting, and / or coupled) in the circumferential direction, while the sides of the adjacent separate tabs 61 intersect each other. In this case, the number of stacked layers of the uncoated portion 43a in the radial direction of the electrode assembly can be further increased.

[0268] Fig. 9b is a cross-sectional view of the bending surface region F, exemplifying the region with increasing stack number and the region with uniform stack number when separate tabs overlap in the circumferential direction.

[0269] With reference to Fig. 9b, the number of stacked layers of the uncoated portion 43a increases sequentially from the outer periphery to the core. The height-variable region of the separate tab starts at a radius of 7 mm (for example, in Fig. 9a). The height of the separate tab starts at 3 mm and increases by 1 mm for every 1 mm increase in radius. When the maximum value of the height of the separate tab is increased to 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm, the number of stacked layers at the radial position where the region with a uniform stacking number begins increases to 18, 22, 26, 30, and 34. Under the same conditions, where the maximum value of the height of the separate tab is 6 mm, 7 mm, and 8 mm, the number of stacked layers is 6 to 8 larger (for example, than that of the example used in conjunction with Fig. 9a). This is because the separate tabs overlap in the circumferential direction.

[0270] Specifically, when the maximum value of the height of the separate tab is 10 mm, the number of stacked layers of the uncoated portion 43a increases up to 34 in the radius range of 9 mm (the stack number increase range) from the outer periphery of the electrode assembly 80 toward the core, and in the radius range of 6 mm toward the core from the radial position where the increase in the number of stacked layers stops, the number of stacked layers of the uncoated portion 43a is maintained at 34, and the number of stacked layers continues to increase to 39 near the core. The number of stacked layers is increased near the core because the separate tabs overlap in the circumferential direction closer to the core. In this example, in the uniform stack number range, the number of stacked layers is 34 or more, and its radial width is 6 mm.The uniform stack count area starts at the radius of 7 mm, and the ratio of the uniform stack count area compared to the radial length (15 mm) of the winding turns including the separate tab is 40% (6 / 15, rounded to zero decimal place, this is applied identically below).

[0271] As another example, when the maximum value of the height of the separate tab is 9 mm, the number of stacked layers of the uncoated portion 43 a increases up to 30 in the radius range of 8 mm from the outer circumference of the electrode assembly 80 toward the core, and in the radius range of 7 mm toward the core from the radial position where the increase in the number of stacked layers stops, the number of stacked layers of the uncoated portion 43 a is maintained at 30 and then further increases to 36 near the core. Therefore, the radial width of the uniform stacking number region is 7 mm, and the number of stacked layers in the uniform stacking number region is 30 or more. The uniform stacking number region starts at the radius of 7 mm, and the ratio of the uniform stacking number region to the radial length (15 mm) of the winding turns including the separate tab is 47% (7 / 15).

[0272] As yet another example, when the maximum value of the height of the separate tab is 8 mm, the number of stacked layers of the uncoated portion 43 a increases up to 26 in the radius range of 7 mm from the outer periphery of the electrode assembly 80 toward the core, and in the radius range of 8 mm toward the core from the radial position where the increase in the number of stacked layers stops, the number of stacked layers of the uncoated portion 43 a is maintained at 26 and then further increased to 28 near the core. Therefore, the radial width of the uniform stacking number region is 8 mm, and the number of stacked layers in the uniform stacking number region is 26 or more. The uniform stacking number region starts at the radius of 7 mm, and the ratio of the uniform stacking number region to the radial length (15 mm) of the winding turns including the separate tab is 53% (8 / 15).

[0273] As yet another example, when the maximum value of the height of the separate tab is 7 mm, the number of stacked layers of the uncoated portion 43 a increases up to 22 in the radius range of 6 mm from the outer periphery of the electrode assembly 80 toward the core, and in the radius range of 9 mm toward the core from the radial position where the increase in the number of stacked layers stops, the number of stacked layers of the uncoated portion 43 a is maintained at 22 and then further increased to 23 near the core. Therefore, the radial width of the uniform stacking number region is 9 mm, and the number of stacked layers in the uniform stacking number region is 22 or more. The uniform stacking number region starts at the radius of 7 mm, and the ratio of the uniform stacking number region compared to the radial length (15 mm) of the winding turns including the separate tab is 60% (9 / 15).

[0274] As yet another example, when the maximum value of the height of the separate tab is 6 mm, the number of stacked layers of the uncoated portion 43 a increases up to 18 in the radius range of 5 mm from the outer periphery of the electrode assembly 80 toward the core, and in the radius range of 10 mm toward the core from the radial position where the increase in the number of stacked layers stops, the number of stacked layers of the uncoated portion 43 a is maintained at 18 and then further increased to 20 near the core. Therefore, the radial width of the uniform stacking number region is 10 mm, and the number of stacked layers in the uniform stacking number region is 18 or more. The area with a uniform number of stacks starts at the radius of 7 mm, and the ratio of the area with a uniform number of stacks compared to the radial length (15 mm) of the winding turns including the separate tab is 67% (10 / 15).

[0275] In Fig. 9b, when the minimum value of the height of the separate flap is 3 mm and the maximum value of the height of the separate flap is 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm, the length of the stacking number increasing region, where the number of stacked layers gradually increases, is increased to 5 mm, 6 mm, 7 mm, 8 mm, and 9 mm. Furthermore, it can be found that the ratio of the uniform stacking number region, where the number of stacked layers is 10 or more, is 40% to 67%.

[0276] In Fig. 9b, the thickness of the bending surface region F increases proportionally to the number of stacked layers of the uncoated portion 43a. The number of stacked layers of the uncoated portion 43a is 18 to 39. In one example, when the uncoated portion 43a is aluminum and its thickness is 10 μm to 25 μm, the thickness of the bending surface region F may be 180 μm to 975 μm. In another example, when the uncoated portion 43a is copper and its thickness is 5 μm to 20 μm, the thickness of the bending surface region F may be 90 μm to 780 μm. If the thickness of the bending surface region F satisfies the condition of the above numerical range, when the current collector is welded to the bending surface region F using a laser, the bending surface region F sufficiently absorbs the laser energy. As a result, weld beads are formed in a sufficient volume on the bending surface area F to increase the weld strength.In addition, the separator and the like located under the bending surface area F can be prevented from being damaged if the welding portion is perforated by the laser.

[0277] The welding area of ​​the current collector may at least partially lie within (overlap and / or be associated with) the uniform range of the stack number based on the radial direction. 50% to 100% of the welding area of ​​the current collector may lie within (overlap and / or be associated with) the uniform range of the stack number in the radial direction of the electrode current collector 80. As the overlap ratio of the welding area increases, it is preferable to increase the weld strength. A region of the welding area of ​​the current collector that does not overlap with the uniform range of the stack number may lie within (overlap and / or be associated with) the increasing range of the stack number.

[0278] With reference to Fig. 9a and Fig. 9b, it will be apparent to those skilled in the art that the uniform range of the number of stacks of the uncoated portion 43a is determined according to the radius (R) of the electrode assembly, the radius (r c ) of the core, the minimum and maximum values ​​of the height of the separate tab in the height variable range of the separate tab, the height increase amount of the separate tab in the radial direction of the electrode assembly.

[0279] The ratio of the area with a uniform number of stacks is inversely proportional to the radius (r c) of the core. Even if the minimum height of the separate tab is the same, the ratio of the area with a uniform stack count increases as the radial width of the height-variable area decreases. Even if the maximum height of the separate tab is the same, the ratio of the area with a uniform stack count increases as the radial width of the height-variable area decreases.

[0280] In an example, if the diameter (R) of the electrode assembly is 22 mm, the radius (r c ) of the core is 2 mm and the height of the separate tab in the radius of 9 mm to 12 mm, which is the height-variable range of the separate tab, is changed from 7 mm to 10 mm, the ratio of the area with a uniform number of stacks can be reduced to the level of 30%.

[0281] In another example, if the diameter (R) of the electrode assembly is 22 mm, the radius (r c) of the core is 2 mm and the height of the separate tab in the radius of 5 mm to 6 mm, which is the height-variable range of the separate tab, is changed from 3 mm to 4 mm, the ratio of the area with a uniform number of stacks can be increased to the level of 85%.

[0282] Accordingly, the radial length of the region with a uniform number of stacks can be 30% or more, in particular 30% to 85%, 40% to 80%, 50% to 75% or 60% to 70%, compared to the radial length of the winding turns including the separate tab.

[0283] Meanwhile, as explained with reference to Fig. 9a and Fig. 9b, when the maximum height of the separate tab in the uniform height region of the separate tab is 6 mm to 10 mm, the number of stacked layers of the uncoated portion 43a in the uniform stacking number region can be adjusted in the range of 10 to 39 by changing the minimum height of the separate tab and the height increment amount of the separate tab in a radial direction. The uniform stacking number region of the bending surface region F includes a region formed by bending the separate tabs included in the uniform height region. The thickness of the bending surface region F varies depending on the thickness of the material constituting the uncoated portion 43a.When the uncoated portion 43a is made of aluminum and its thickness is 10 μm to 25 μm, the stacking thickness of the uncoated portion in the bending surface region F is 100 μm (0.1 mm) to 975 μm (0.975 mm). In this case, the ratio of the stacking thickness of the uncoated portion in the bending surface region F to the height of the separate tab in the bending surface region F formed by bending the separate tabs with a height of 6 mm to 10 mm included in the uniform height region is 1.0% (0.1 mm / 10 mm) to 16.3% (0.975 mm / 6 mm). In another example, when the uncoated portion 43a is made of copper and its thickness is 5 μm to 20 μm, the stack thickness of the uncoated portion in the bending surface area F is 50 μm (0.05 mm) to 780 μm (0.780 mm).In this case, the ratio of the stack thickness of the uncoated portion in the bending surface region F to the height of the separate tab in the bending surface region F formed by bending the separate tabs with a height of 6 mm to 10 mm included in the uniform height region is 0.5% (0.05 mm / 10 mm) to 13.0% (0.780 mm / 6 mm). When the thickness ratio of the bending surface region (F) to the height of the separate tabs included in the uniform height region satisfies the above numerical range, the desired welding strength can be achieved when the current collector is welded to the bending surface region F.

[0284] Various electrode assembly structures according to the embodiments (modifications) of the present disclosure can be applied to a cylindrical battery or any other batteries known in the art.

[0285] The cylindrical battery may, for example, be a cylindrical battery whose form factor ratio (defined as a value obtained by dividing the diameter of the cylindrical battery by the height, namely a ratio of diameter (Φ) to height (H)) is greater than about 0.4, or greater than 0.35, or greater than 0.42, or greater than 0.45, or greater than 0.48, or greater than 0.5, or greater than 5.5, or greater than 5.7, and less than 1.0, or less than 0.9, or less than 0.8, or less than 0.7, or less than 0.6. In particular, the diameter of the cylindrical battery may be between 40 mm and 50 mm, in particular 46 mm, while the height of the cylindrical battery may be between 70 mm and 90 mm, in particular 80 mm.

[0286] The form factor here refers to a value that indicates the diameter and height of a cylindrical battery. For example, the form factor of a cylindrical battery can be 46110, 4875, 48110, 4880, 4680, or the like. 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.

[0287] When an electrode assembly with a tabless structure is applied to a cylindrical battery with an aspect ratio of more than 0.4, the stress applied in the radial direction when the uncoated portion is bent is large, so the uncoated portion is easily torn. Furthermore, when welding the current collector to the bending surface area of ​​the uncoated portion, it is necessary to sufficiently increase the number of stacked layers of the uncoated portion to sufficiently secure 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.

[0288] A battery may be a cylindrical battery having an approximately cylindrical shape, a diameter of approximately 46 mm, a height of approximately 110 mm, and a form factor ratio of 0.418.

[0289] A battery may be a cylindrical battery having a substantially cylindrical shape, having a diameter of approximately 48 mm, a height of approximately 75 mm, and a form factor ratio of 0.640.

[0290] A battery may be a cylindrical battery having an approximately cylindrical shape, a diameter of approximately 48 mm, a height of approximately 110 mm, and a form factor ratio of 0.436.

[0291] A battery may be a cylindrical battery having an approximately cylindrical shape, a diameter of approximately 48 mm, a height of approximately 80 mm, and a form factor ratio of 0.600.

[0292] A battery may be a cylindrical battery having an approximately cylindrical shape, a diameter of approximately 46 mm, a height of approximately 80 mm, and a form factor ratio of 0.575.

[0293] Conventionally, batteries with a form factor ratio of approximately 0.4 or less were used. For example, 1865 batteries, 2170 batteries, etc. were conventionally used. The 1865 battery has a diameter of approximately 18 mm, a height of approximately 65 mm, and a form factor ratio of 0.277. The 2170 battery has a diameter of approximately 21 mm, a height of approximately 70 mm, and a form factor ratio of 0.300.

[0294] The cylindrical battery is described in detail below.

[0295] Fig. 10 is a sectional view showing a cylindrical battery 190 along the Y-axis direction.

[0296] With reference to Fig. 10, the cylindrical battery 190 includes an electrode assembly 110 having a first electrode, a separator, and a second electrode, a battery case 142 for accommodating the electrode assembly 110, and a sealing body 143 for sealing an open end of the battery case 142.

[0297] The battery housing 142 is a cylindrical container with an opening at the top. The battery housing 142 is made of a conductive metal material, such as aluminum or steel. The battery housing 142 accommodates the electrode assembly 110 in the interior through the top opening and also accommodates the electrolyte.

[0298] The electrolyte may be a salt having a structure such as A+B-. Here, A+ comprises an alkali metal cation, such as Li+, Na+ or K+, or a combination thereof, and B- comprises at least one anion selected from the group consisting of F - , Cl - , Br - , I - , NO3 -, N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , ASF6 - , BF2C2O4 - , BC4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - und (CF3CF2SO2)2N - besteht.

[0299] The electrolyte can also be dissolved in an organic solvent. The organic solvent can 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), ethyl methyl carbonate (EMC), γ-butyrolactone, or a mixture thereof.

[0300] The electrode assembly 110 may have a jelly-roll shape or any other rolled shapes known in the art. The electrode assembly 110 may be manufactured by winding a laminate formed by sequentially laminating a lower separator, a first electrode, an upper separator, and a second electrode at least once based on the winding center C, as shown in Fig. 2 shown.

[0301] The first electrode and the second electrode have different polarities. That is, when one has positive polarity, the other has 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).

[0302] An uncoated portion 146a of the first electrode and an uncoated portion 146b of the second electrode protrude from the upper and lower portions of the electrode assembly 110, respectively.

[0303] The sealing body 143 may include a cap 143a, a first gasket 143b for providing airtightness between the cap 143a and the battery case 142 and having insulation, and a connecting plate 143c electrically and mechanically coupled to the cap 143a.

[0304] The cap 143a is a component made of a conductive metal material and covers the top opening of the battery case 142. The cap 143a is electrically connected to the uncoated portion 146a of the first electrode and is electrically insulated from the battery case 142 by the first seal 143b. Accordingly, the cap 143a can function as a first electrode terminal of the cylindrical battery 140.

[0305] The cap 143a is placed on the bead portion 147 formed on the battery case 142 and is fixed by a crimp portion 148. The first gasket 143b may be interposed between the cap 143a and the crimp portion 148 to ensure the airtightness of the battery case 142 and the electrical insulation between the battery case 142 and the cap 143a. The cap 143a may have a projection 143d projecting upward from the center thereof.

[0306] The battery housing 142 is electrically connected to the uncoated portion 146b of the second electrode. Therefore, the battery housing 142 has the same polarity as the second electrode. If the second electrode has negative polarity, the battery housing 142 also has negative polarity.

[0307] 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 110 housed inside the battery case 142 from leaking through the top opening of the battery case 142 and can function as a support portion on which the sealing body 143 is placed.

[0308] The crimping portion 148 is formed on the bead portion 147. The crimping portion 148 has an elongated and curved shape to cover the outer periphery of the cap 143a disposed on the bead portion 147 and a part of the upper surface of the cap 143a.

[0309] The cylindrical battery 140 may further include a first current collector 144 and / or a second current collector 145 and / or an insulator 146.

[0310] The first current collector 144 is coupled to the upper portion of the electrode assembly 110. The first current collector 144 is made of a conductive metal material, such as aluminum, copper, nickel, and so on, and is electrically connected to the bending surface region F1 formed when the uncoated portion 146a of the first electrode is bent.

[0311] A lead 149 may be connected to the first current collector 144. The lead 149 may extend upwardly above the electrode assembly 110 and be coupled to the connecting plate 143c or be directly coupled to the lower surface of the cap 143a. The lead 149 may be connected to other components by welding.

[0312] The first current collector 144 may be formed integrally with the line 149. In this case, the line 149 may have an elongated plate shape that extends outward near the center of the first current collector 144.

[0313] The bending surface area (F1) of the uncoated portion 146a and the first current collector 144 may be coupled, for example, by laser welding. Laser welding may be performed in a manner that partially melts a base material of the current collector. Laser welding may be replaced by resistance welding, ultrasonic welding, or the like.

[0314] The uncoated portion 146a is divided into a plurality of separate tabs, and the bending surface region (F1) is formed by bending the plurality of separate tabs toward the core C. In the bending surface region (F1), the radial length of a region where the number of stacked layers of the uncoated portion 146a is 10 or more may be 30% or more, particularly 30% to 85%, 40% to 80%, 50% to 75%, or 60% to 70%, compared to the radial length of the winding turns including the separate tab.

[0315] The welding area between the bending surface area (F1) of the uncoated portion 146a and the first current collector 144 may be within and / or overlap the uniform range (W1) of the stacking number of the bending surface area (F1) by 50% or more, and it is preferable if the overlap ratio is higher.

[0316] When the bending surface area (F1) of the uncoated portion 146a and the first current collector 144 are welded with a laser, the welding strength can be particularly 2 kgf / cm 2 or more, especially 4 kgf / cm 2 or more. The upper limit of the welding strength may depend on the specification of the laser welding equipment. For example, the welding strength may be limited to 8 kgf / cm 2 or less or 6 kgf / cm 2or less. The laser power required to achieve the weld strength varies depending on the laser welding equipment. In one example, the laser power may be in the range of 250 W to 320 W. In another example, the laser power may be set in the range of 40% to 100% of the maximum power specification of the laser welding equipment.

[0317] When the welding strength satisfies the above numerical range, the properties of the welding interface do not deteriorate even if strong vibrations are applied to the electrode assembly 110 along the winding axis direction and / or the radial direction, and since the volume of the weld beads is sufficient, the resistance of the welding interface can also be reduced.

[0318] The second current collector 145 may be coupled to the bottom surface of the electrode assembly 110. One side of the second current collector 145 may be welded to the bending surface area (F2) formed when the uncoated portion 146b of the second electrode is bent, and the other side may be welded to the inner bottom surface of the battery case 142.

[0319] The uncoated portion 146b is divided into a plurality of separate tabs, and the bending surface region (F2) is formed by bending the plurality of separate tabs toward the core C. In the bending surface region (F2), the radial length of a region where the number of stacked layers of the uncoated portion 146b is 10 or more may be 30% or more, particularly 30% to 85%, 40% to 80%, 50% to 75%, or 60% to 70%, compared to the radial length of the winding turns including the separate tab.

[0320] The coupling structure between the second current collector 145 and the uncoated portion 146b of the second electrode may be substantially the same as the coupling structure between the first current collector 144 and the uncoated portion 146a of the first electrode.

[0321] The welding area between the bending surface area (F2) of the uncoated portion 146b and the second current collector 145 may be within and / or overlap the uniform range (W2) of the number of stacks by 50% or more, and it is preferable if the overlap ratio is higher.

[0322] Specifically, when the bending surface area (F2) of the uncoated portion 146b and the second current collector 145 are welded with a laser, the welding strength is 2 kgf / cm 2 or more, especially 4 kgf / cm 2 or more. The upper limit of the welding strength may depend on the specification of the laser welding equipment. For example, the welding strength may be limited to 8 kgf / cm 2 or less or 6 kgf / cm 2or less. The laser power required to achieve the weld strength varies depending on the laser welding equipment. In one example, the laser power may be in the range of 250 W to 320 W. In another example, the laser power may be set in the range of 40% to 100% of the maximum power specification of the laser welding equipment.

[0323] When the welding strength satisfies the above numerical range, the properties of the welding interface do not deteriorate even if strong vibrations are applied to the electrode assembly 110 along the winding axis direction and / or the radial direction, and since the volume of the weld beads is sufficient, the resistance of the welding interface can also be reduced.

[0324] The insulator 146 may cover the first current collector 144. The insulator 146 may cover the first current collector 144 at 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.

[0325] 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 therethrough. The lead 149 is pulled upward through the lead hole 151 and coupled to the lower surface of the connecting plate 143c or the lower surface of the cap 143a.

[0326] 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 110 and the first current collector 144. Accordingly, the movement of the coupled body of the electrode assembly 110 and the first current collector 144 in the height direction of the battery 140 can be restricted, thereby improving the assembly stability of the battery 140.

[0327] 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.

[0328] 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 with a smaller thickness compared to the peripheral region of the lower surface of the battery case 142. The vent portion 152 is structurally weak compared to the surrounding surface. Accordingly, when an abnormality occurs in the cylindrical battery 190 and the internal pressure increases to a predetermined level or more, the vent portion 152 may be ruptured, so that the gas generated inside the battery case 142 is discharged to the outside.

[0329] The vent portion 152 may be formed continuously or discontinuously, while a circle is drawn on the bottom surface of the battery case 142. In a modification, the vent portion 152 may be formed in a straight pattern or other patterns.

[0330] Fig. 11 is a sectional view showing a cylindrical battery 200 along the Y-axis.

[0331] With reference to Fig. 11, the structure of the electrode assembly of the cylindrical battery 200 is substantially the same as that of the cylindrical battery 190 of Fig. 10, and the other structure except the electrode assembly is changed.

[0332] Specifically, the cylindrical battery 200 includes a battery case 171 through which a terminal 172 is installed. The terminal 172 is installed on the closed surface (the upper surface in the drawing) of the battery case 171. The terminal 172 passes through a perforation hole of the battery case 171 in a state where a second gasket 173 made of an insulating material is interposed. The terminal 172 is exposed to the outside in a direction opposite to the direction of gravity.

[0333] The terminal 172 includes a terminal exposure portion 172a and a terminal insertion portion 172b. The terminal exposure portion 172a is exposed to the outside of the closed surface of the battery case 171. The terminal exposure portion 172a may be located approximately at a central portion of the closed surface of the battery case 171. The maximum diameter of the terminal exposure portion 172a may be larger than the maximum diameter of the perforation hole formed in the battery case 171. The terminal insertion portion 172b may be electrically connected to the uncoated portion 146a of the first electrode through approximately the central portion of the closed surface of the battery case 171. The terminal insertion portion 172b may be inserted and deformed onto the inner surface of the battery case 171.The terminal insertion portion may penetrate through (the perforation hole) the inner surface of the battery case or may be figuratively riveted through it. That is, the lower edge of the terminal insertion portion 172b may have a shape curved toward the inner surface of the battery case 171. The maximum diameter of the end of the terminal insertion portion 172b may be larger than the maximum diameter of the perforation hole of the battery case 171.

[0334] The lower surface of the terminal insertion portion 172b is substantially flat and may be welded to the central portion of the first current collector 144, which is connected to the uncoated portion 146a of the first electrode. 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 110. Accordingly, the uncoated portion 146a exposed on the outer periphery of the electrode assembly 110 can be prevented from contacting the inner surface of the battery case 171, which has a different polarity, to cause a short circuit.

[0335] The insulator 174 is in contact with the inner surface of the closed portion of the battery case 171 and in contact with the upper surface of the first current collector 144. For this purpose, the insulator 174 has a thickness corresponding to the separation distance between the inner surface of the closed portion of the battery case 171 and the upper surface of the first current collector 144, or a thickness slightly larger than the separation distance.

[0336] The first current collector 144 can be laser welded to the bending surface area F1 of the uncoated portion 146a. At this time, welding is performed in a region including the uniform stacking number region where the number of stacked layers of the uncoated portion 146a in the bending surface area F1 of the uncoated portion 146a is 10 or more.

[0337] The radial length of the uniform stack number region in which the number of stacked layers of the uncoated portion 146a is 10 or more may be 30% or more, in particular 30% to 85%, 40% to 80%, 50% to 75%, or 60% to 70%, compared to the radial length of the winding turns including the separate tab.

[0338] The welding area between the bending surface area (F1) of the uncoated portion 146a and the first current collector 144 may be within and / or overlap the uniform range (W1) of the number of stacks by 50% or more, and it is preferable if the overlap ratio is higher.

[0339] When the bending surface area (F1) of the uncoated portion 146a and the first current collector 144 are welded with a laser, the welding strength can be particularly 2 kgf / cm 2 or more, especially 4 kgf / cm 2or more. The upper limit of the welding strength may depend on the specification of the laser welding equipment. For example, the welding strength may be limited to 8 kgf / cm 2 or less or 6 kgf / cm 2 or less. The laser power required to achieve the weld strength varies depending on the laser welding equipment. In one example, the laser power may be in the range of 250 W to 320 W. In another example, the laser power may be set in the range of 40% to 100% of the maximum power specification of the laser welding equipment.

[0340] When the welding strength satisfies the above numerical range, the properties of the welding interface do not deteriorate even if strong vibrations are applied to the electrode assembly 110 along the winding axis direction and / or the radial direction, and since the volume of the weld beads is sufficient, the resistance of the welding interface can also be reduced.

[0341] The second seal 173 is interposed between the battery case 171 and the terminal 172 to prevent the battery case 171 and the terminal 172, which have opposite polarities, from electrically contacting each other. Accordingly, the upper surface of the battery case 171, which has a roughly flat shape, can function as a second electrode terminal of the cylindrical battery 200.

[0342] The second gasket 173 includes a gasket exposure portion 173a and a gasket insertion portion 173b. The gasket exposure portion 173a is interposed between the terminal exposure portion 172a of the terminal 172 and the battery case 171. The gasket insertion portion 173b is interposed between the terminal insertion portion 172b of the terminal 172 and the battery case 171. The gasket insertion portion 173b can be deformed together when the terminal insertion portion 172b is riveted to be in close contact with the inner surface of the battery case 171. The second gasket 173 can be made of, for example, a polymer resin with insulation.

[0343] The seal exposure portion 173a of the second seal 173 may have an elongated shape to cover the outer periphery of the terminal exposure portion 172a of the terminal 172. When the second seal 173 covers the outer periphery of the terminal 172, a short circuit can be prevented 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 exposure portion 173a may have an elongated shape to cover not only the outer peripheral surface of the terminal exposure portion 172a but also part of the upper surface thereof.

[0344] 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 thermofusion. In this case, the airtightness can be improved at the coupling interface between the second gasket 173 and the terminal 172 and at the coupling interface between the second gasket 173 and the battery case 171. Meanwhile, when the gasket exposure portion 173a of the second gasket 173 has a shape extending toward the upper surface of the terminal exposure portion 172a, the terminal 172 may be integrally coupled to the second gasket 173 by insert molding.

[0345] In the upper surface of the battery case 171, a remaining area 175 other than the area occupied by the terminal 172 and the second seal 173 corresponds to the second electrode terminal having a polarity opposite to that of the terminal 172.

[0346] The second current collector 176 is coupled to the lower portion of the electrode assembly 110. The second current collector 176 is made of a conductive metal material, such as aluminum, steel, copper, or nickel, and is electrically connected to the uncoated portion 146b of the second electrode.

[0347] The second current collector 176 is electrically connected to the battery housing 171. For this purpose, at least a portion of the edge of the second current collector 176 may be inserted and fixed between the inner surface of the battery housing 171 and a first seal 178b.

[0348] In one example, at least a portion of the edge of the second current collector 176 may be fixed to the bead portion 180 by welding in a state where it is supported on the lower surface of the bead portion 180 formed at the bottom of the battery case 171. In a modification, at least a portion of the edge of the second current collector 176 may be welded directly to the inner wall surface of the battery case 171.

[0349] The second current collector 176 and the bending surface area (F2) of the uncoated portion 146b may be coupled by welding, for example, laser welding. At this time, welding is performed in a region including a uniform stacking number region in which the number of stacked layers of the uncoated portion 146b in the bending surface area (F2) of the uncoated portion 146b is 10 or more.

[0350] The radial length of the region in which the number of stacked layers of the uncoated portion 146b is 10 or more may be 30% or more, in particular 30% to 85%, 40% to 80%, 50% to 75%, or 60% to 70%, compared to the radial length of the winding turns including the separate tab.

[0351] The welding area between the bending surface area (F2) of the uncoated portion 146b and the second current collector 176 may be within and / or overlap the uniform range (W2) of the number of stacks by 50% or more, and it is preferable if the overlap ratio is higher.

[0352] Specifically, when the bending surface area (F2) of the uncoated portion 146b and the second current collector 176 are welded with a laser, the welding strength is 2 kgf / cm 2 or more, especially 4 kgf / cm 2 or more.

[0353] When the welding strength satisfies the above numerical range, the properties of the welding interface do not deteriorate even if strong vibrations are applied to the electrode assembly 110 along the winding axis direction and / or the radial direction, and since the volume of the weld beads is sufficient, the resistance of the welding interface can also be reduced.

[0354] A sealing body 178 for sealing the lower open end of the battery case 171 includes a cap 178a and a first seal 178b. The first seal 178b electrically separates the cap 178a and the battery case 171. A crimping portion 181 fixes the edge of the cap 178a and the first seal 178b together. The cap 178a has a vent portion 179. The configuration of the vent portion 179 is substantially the same as the above embodiment (modification).

[0355] The cap 178a is made of a conductive metal material. However, since the first seal 178b is interposed between the cap 178a and the battery case 171, the cap 178a has no electrical polarity. The seal body 178 seals the open end of the lower portion of the battery case 171 and functions to discharge gas when the internal pressure of the battery 200 increases above a critical value.

[0356] Terminal 172, which is electrically connected to the uncoated portion 146a of the first electrode, is used as the first electrode terminal. Furthermore, in the upper surface of the battery case 171, which is electrically connected to the uncoated portion 146b of the second electrode through the second current collector 176, a part 175, except for terminal 172, which has a different polarity from the first electrode terminal, is used as the second electrode terminal. When two electrode terminals are located at the upper portion of the cylindrical battery 200 as above, it is possible to dispose electrical connection components such as bus bars on only one side of the cylindrical battery 200. This can simplify the battery pack structure and improve energy density.Furthermore, since the part 175 used as the second electrode terminal has a roughly flat shape, a sufficient connection area can be secured for connecting electrical connection components such as busbars. Accordingly, the cylindrical battery 200 can reduce the resistance at the connection portion of the electrical connection components to a desirable level.

[0357] In the present disclosure, the core C of the electrode assembly 110 can be opened upward without being blocked even if the uncoated portions 146a, 146b are bent toward the core.

[0358] That is, as in Fig. 4, the height of the uncoated portion of the first and second electrodes, particularly the height of the core-side uncoated portion A, is designed to be low, and the height-variable portion of the separate tab 61 is arranged adjacent to the core-side uncoated portion A, so that by adjusting the height of the separate tab 61 closest to the core-side uncoated portion A, the core C of the electrode assembly 110 is not blocked even if the uncoated portion near the core of the electrode assembly 110 is bent.

[0359] When core C is not blocked, there are no difficulties in the electrolyte injection process, and the electrolyte injection efficiency is improved. Furthermore, by inserting a welding jig through core C, the welding process between current collector 145 and the bottom of battery case 142 or the welding process between current collector 144 and terminal 172 can be easily performed.

[0360] When the uncoated portions 146a, 146b have a separate tab structure, if the width and / or height and / or separation pitch of the separate tabs are set to satisfy the numerical ranges of the above embodiment, the separate tabs are overlapped in multiple layers to sufficiently secure the welding strength when the separate tabs are bent, and a void (gap) is not formed on the bending surface area (F1, F2).

[0361] Meanwhile, the first current collector 144 and the second current collector 176 may have a new structure as shown in Fig. 12 and Fig. 13 shown.

[0362] Fig. 12 is a plan view showing the structure of the first current collector 144.

[0363] With reference to Fig. 12, the first current collector 144 may include an edge portion 144a, a first coupling portion 144b of the uncoated portion, and a terminal coupling portion 144c. The edge portion 144a is disposed on the electrode assembly 110. The edge portion 144a may have a substantially annular shape in which an empty space S is formed. In the drawings of the present disclosure, only a case where the edge portion 144a has a substantially circular annular shape is illustrated, but the present disclosure is not limited thereto. The edge portion 61 may have a substantially rectangular annular shape, a hexagonal annular shape, an octagonal annular shape, or other annular shapes other than the illustrated one.

[0364] The terminal coupling portion 144c may have a diameter equal to or larger than the diameter of the flat portion formed on the lower surface of the terminal 172 to secure a welding area for coupling with the flat portion formed on the lower surface of the terminal 172.

[0365] The first coupling portion 144b of the uncoated portion extends inward from the edge portion 144a and is coupled to the uncoated portion 146a. The terminal coupling portion 144c is spaced apart from the first coupling portion 144b of the uncoated portion and is positioned within the edge portion 144a. The terminal coupling portion 144c may be coupled to the terminal 172 by welding. For example, the terminal coupling portion 144c may be located approximately in the center of the interior space surrounded by the edge portion 144a. The terminal coupling portion 144c may be provided at a position corresponding to the hole formed in the core C of the electrode assembly 110.The terminal coupling portion 144c may be configured to cover the hole formed in the core C of the electrode assembly 110 so that the hole formed in the core C of the electrode assembly 110 is not exposed from the terminal coupling portion 144c. For this purpose, the terminal coupling portion 144c may have a larger diameter or width than the hole formed in the core C of the electrode assembly 110.

[0366] The first coupling portion 144b of the uncoated portion and the terminal coupling portion 144c may not be directly connected, but may be arranged to be spaced apart from each other and indirectly connected by the edge portion 144a. Since the first current collector 144 has a structure in which the first coupling portion 144b of the uncoated portion and the terminal coupling portion 144c are not directly connected to each other, but are connected by the edge portion 144c as above, when shock and / or vibration occur on the cylindrical battery 200, it is possible to disperse the shock applied to the coupling portion between the first coupling portion 144b of the uncoated portion and the first uncoated portion 146a, and the coupling portion between the terminal coupling portion 144c and the terminal 172.In the drawings of the present disclosure, only a case where four first coupling portions 144b of the uncoated portion are provided is illustrated, but the present disclosure is not limited to this. The number of first coupling portions 144b of the uncoated portion can be determined differently, taking into account the manufacturing difficulty, according to the complexity of the shape, the electrical resistance, the space within the edge portion 144a, the electrolyte impregnation, and the like.

[0367] The first current collector 144 may further include a bridge portion 144d extending inward from the edge portion 144a and connected to the terminal coupling portion 144c. At least a portion of the bridge portion 144d may have a smaller cross-sectional area compared to the first coupling portion 144b of the uncoated portion and the edge portion 144a. For example, at least a portion of the bridge portion 144d may be formed to have a smaller width and / or thickness compared to the first coupling portion 144b of the uncoated portion. In this case, the electrical resistance in the bridge portion 144d increases, and thus, when a current flows through the bridge portion 144d, the relatively large resistance causes a portion of the bridge portion 144d to melt due to overcurrent heating, thereby irreversibly blocking the overcurrent.The cross-sectional area of ​​the bridge section 144d can be set to an appropriate level taking into account the overcurrent blocking function.

[0368] The bridge portion 144d may include a tapered portion 144e whose width gradually decreases from the inner surface of the edge portion 144a toward the terminal coupling portion 144c. Providing the tapered portion 144e can improve the rigidity of the component at the connecting portion between the bridge portion 144d and the edge portion 144a. Providing the tapered portion 144e allows, for example, a transfer device and / or a worker to easily and safely transport the first current collector 144 and / or a coupled body of the first current collector 144 and the electrode assembly 110 by grasping the tapered portion 144e during the manufacturing process of the cylindrical battery 200.That is, when the tapered portion 144e is provided, it is possible to prevent product defects that may occur by gripping a portion where welding is performed with other components such as the coupling portion 144b of the first uncoated portion and the terminal coupling portion 144c.

[0369] The coupling portion 144b of the first uncoated portion may be provided in multiples. The plurality of coupling portions 144b of the first uncoated portion may be arranged substantially at regular intervals from one another in the extending direction of the edge portion 144a. An extending length of each of the plurality of coupling portions 144b of the first uncoated portion may be substantially equal to one another. The coupling portion 144b of the first uncoated portion may be coupled to the bending surface region (F1) of the uncoated portion 146a by laser welding. The welding pattern 144f formed by welding between the coupling portion 144b of the first uncoated portion and the bending surface region (F1) may have a structure to extend along the radial direction of the electrode assembly 110.The welding pattern 144f may be a line pattern or a dot array pattern.

[0370] The terminal coupling portion 144c may be arranged to be surrounded by the plurality of coupling portions 144b of the first uncoated portion. The terminal coupling portion 144c may be coupled to the terminal 172 by welding. The bridge portion 144d may be positioned adjacent to each other between a pair of coupling portions 144b of the first uncoated portion. In this case, the distance from the bridge portion 144d to any one of the pair of coupling portions 144b of the first uncoated portion along the extending direction of the edge portion 144a may be substantially equal to the distance from the bridge portion 144d to the other of the pair of coupling portions 144b of the first uncoated portion along the extending direction of the edge portion 144a.The plurality of coupling portions 144b of the first uncoated portion may be configured to have substantially the same cross-sectional area. The plurality of coupling portions 144b of the first uncoated portion may be configured to have substantially the same width and thickness.

[0371] Although not shown in the drawings, the bridge portion 144d may be provided in multiples. Each of the plurality of bridge portions 144d may be disposed adjacent to each other between a pair of coupling portions 144b of the first uncoated portion. The plurality of bridge portions 144d may be arranged at substantially regular intervals from each other in the extending direction of the edge portion 144a. A distance from each of the plurality of bridge portions 144d to one of the pair of coupling portions 144b of the first uncoated portion adjacent to each other along the extending direction of the edge portion 144a may be substantially equal to a distance from each of the plurality of bridge portions 144d to the other coupling portion 144b of the first uncoated portion.

[0372] In the case where the coupling portion 144b of the first uncoated portion and / or the bridge portion 144d is provided in plural numbers as described above, if the distance between the coupling portions 144b of the first uncoated portion and / or the distance between the bridge portions 144d and / or the distance between the coupling portion 144b of the first uncoated portion and the bridge portion 144d is formed uniformly, a current flowing from the coupling portion 144b of the first uncoated portion to the bridge portion 144d or a current flowing from the bridge portion 144d to the coupling portion 144b of the first uncoated portion can be formed smoothly and uniformly.

[0373] Meanwhile, the first current collector 144 and the bending surface area (F1) of the uncoated portion 146a can be coupled by welding. In this case, for example, laser welding, ultrasonic welding, spot welding, or the like can be used. The welding area can be within the uniform range (W1) of the stacking number of the bending surface area (F1) by 50% or more and / or overlap it.

[0374] The bridge portion 144d may include a notch portion N configured to partially reduce a cross-sectional area of ​​the bridge portion 144d. The cross-sectional area of ​​the notch portion N may be adjusted, for example, by partially reducing the width and / or thickness of the bridge portion 144d. When the notch portion N is provided, the electrical resistance in the region where the notch portion N is formed is increased, thereby enabling rapid current interruption when an overcurrent occurs.

[0375] Specifically, the notch portion N is provided in a region corresponding to the uniform overlapping layer area of ​​the electrode assembly 110 to prevent foreign matter generated during breakage from flowing into the electrode assembly 110. This is because, in this region, the number of overlapped layers of the separate tabs of the uncoated portion 146a is kept to the maximum, and thus, the overlapped separate tabs can function as a mask. For example, the notch portion N may be provided in a region where the number of stacked layers of the uncoated portion 146a is maximum in the uniform stacking number area.

[0376] Fig. 13 is a plan view showing the structure of the second current collector 176.

[0377] With reference to Fig. 13, the second current collector 176 is arranged below the electrode assembly 110. Furthermore, the second current collector 176 may be configured to electrically connect the uncoated portion 146b of the electrode assembly 110 and the battery case 171. The second current collector 176 is formed of a metal material having conductivity and is electrically connected to the uncoated portion 146b. Furthermore, the second current collector 176 is electrically connected to the battery case 171. The second current collector 176 may be inserted and fixed between the inner surface of the battery case 171 and the first gasket 178b. Specifically, the second current collector 176 may be inserted between the underside of the bead portion 180 of the battery case 171 and the first gasket 178b.However, the present disclosure is not limited thereto, and the second current collector 176 may be welded to the inner wall surface of the battery case 171 in a region where the bead portion 180 is not formed.

[0378] The second current collector 176 may include a support portion 176a disposed below the electrode assembly 110, a second uncoated portion coupling portion 176b extending from the support portion 176a approximately along the radial direction of the electrode assembly 110 and coupled to the bending surface area (F2) of the uncoated portion 146b, and a case coupling portion 176c extending from the support portion 176a approximately along the radial direction of the electrode assembly 110 and coupled to the inner surface of the battery case 171. The second uncoated portion coupling portion 176b and the case coupling portion 176c are indirectly connected through the support portion 176a and are not directly connected to each other.Therefore, when an external impact is applied to the cylindrical battery 200 of the present disclosure, it is possible to minimize the risk of damage to the coupling portion of the second current collector 176 and the electrode assembly 110, and to the coupling portion of the second current collector 176 and the battery case 171. However, the second current collector 176 of the present disclosure is not limited to the structure in which the coupling portion 176b of the second uncoated portion and the case coupling portion 176c are only indirectly connected. For example, the second current collector 176 may have a structure that does not include the support portion 176a for indirectly connecting the coupling portion 176b of the second uncoated portion and the case coupling portion 176c, and / or a structure in which the uncoated portion 176b and the case coupling portion 176c are directly connected to each other.

[0379] The support portion 176a and the coupling portion 176b of the second uncoated portion are arranged below the electrode assembly 110. The coupling portion 176b of the second uncoated portion is coupled to the bending surface area (F2) of the uncoated portion 146b. In addition to the coupling portion 176b of the second uncoated portion, the support portion 176a may also be coupled to the uncoated portion 146b. The coupling portion 176b of the second uncoated portion and the uncoated portion 146b may be coupled by welding. The support portion 176a and the coupling portion 176b of the second uncoated portion are located higher than the bead portion 180 when the bead portion 180 is formed on the battery case 171.

[0380] The support portion 176a has a current collector hole 176d formed at a location corresponding to the hole formed in the core C of the electrode assembly 110. The core C of the electrode assembly 110 and the current collector hole 176d, which communicate with each other, can function as a passage for inserting a welding rod for welding between the terminal 172 and the terminal coupling portion 144c of the first current collector 144 or for irradiating a laser beam. The current collector hole 176d can have a diameter substantially equal to or larger than the hole formed in the core C of the electrode assembly 110.When the coupling portion 176b of the second uncoated portion is provided in multiples, the plurality of coupling portions 176b of the second uncoated portion may have a shape that extends approximately radially from the support portion 176a of the second current collector 176 toward the side wall of the battery case 171. The plurality of coupling portions 176b of the second uncoated portion may be positioned to be spaced apart from each other along the circumference of the support portion 176a.

[0381] The housing coupling portion 176c may be provided in multiples. In this case, the plurality of housing coupling portions 176c may have a shape that extends approximately radially from the center of the second current collector 176 toward the side wall of the battery housing 171. Accordingly, the electrical connection between the second current collector 176 and the battery housing 171 can be established at a plurality of locations. Since the coupling for the electrical connection is established at a plurality of locations, the coupling area can be maximized, thereby minimizing the electrical resistance. The plurality of housing coupling portions 176c may be positioned to be spaced apart from each other along the circumference of the support portion 176a. At least one housing coupling portion 176c may be positioned adjacent to each other between the coupling portions 176b of the second uncoated portion.The plurality of housing coupling portions 176c may, for example, be coupled to the bead portion 180 in the inner surface of the battery housing 171. The housing coupling portions 176c may be coupled by welding, particularly to the lower surface of the bead portion 180. The welding may use, for example, laser welding, ultrasonic welding, or spot welding. By coupling the housing coupling portions 176c to the bead portion 180 by welding in this way, the resistance level of the cylindrical battery 200 may be limited to approximately 4 milliohms or less, 3 milliohms or less, 2 milliohms or less, or 0.5 milliohms or less. The resistance level of the cylindrical battery 200 may be at least 0.5 milliohms or at least 1.0 milliohms.Furthermore, since the lower surface of the bead portion 180 has a shape extending in a direction approximately parallel to the upper surface of the battery case 171, namely, in a direction approximately perpendicular to the side wall of the battery case 171, and the case coupling portion 176c also has a shape extending in the same direction, namely, in the radial direction and the circumferential direction, the case coupling portion 176c can stably contact the bead portion 180. Furthermore, since the case coupling portion 176c stably contacts the flat portion of the bead portion 180, the two components can be smoothly welded, thereby improving the coupling force between the two components and minimizing the increase in resistance at the coupling portion.

[0382] The housing coupling portion 176c may include a contact portion 176e coupled to the inner surface of the battery case 171 and a connecting portion 176f for connecting the support portion 176a and the contact portion 176e.

[0383] The contact portion 176e is coupled to the inner surface of the battery case 171. In the case where the bead portion 180 is formed on the battery case 171, the contact portion 176e may be coupled to the bead portion 180 as described above. Specifically, the contact portion 176e may be electrically coupled to the flat portion formed on the lower surface of the bead portion 180 formed on the battery case 171 and may be interposed between the lower surface of the bead portion 180 and the first gasket 178b. In this case, for stable contact and coupling, the contact portion 176e may have a shape extending from the bead portion 180 by a predetermined length along the circumferential direction of the battery case 171.

[0384] Meanwhile, the maximum distance from the center of the second current collector 176 to the end of the coupling portion 176b of the second uncoated portion along the radial direction of the electrode assembly 110 is specifically equal to or smaller than the inner diameter of the battery case 171 in a region where the bead portion 180 is formed, namely the minimum inner diameter of the battery case 171. This is to prevent the second current collector 176 from being interfered by the bead portion 180 during the dimensioning process of compressing the battery case 171 along the height direction, and thus prevent the electrode assembly 110 from being pressed by the second current collector 176.

[0385] The coupling portion 176b of the second uncoated portion includes a hole 176g. The hole 176g can be used as a passage through which the electrolyte can move. The weld pattern 176h formed by welding between the coupling portion 176b of the second uncoated portion and the bending surface region (F2) can have a structure extending along the radial direction of the electrode assembly 110. The weld pattern 176h can be a line pattern or a dot array pattern.

[0386] The cylindrical battery 200 has an advantage in that electrical connection can be performed at its upper portion.

[0387] Fig. 14 is a plan view illustrating a state in which a plurality of cylindrical batteries 200 are electrically connected, and Fig. 15 is a partially enlarged view of Fig. 14.

[0388] With reference to Fig. 14 and Fig. 15, a plurality of cylindrical batteries 200 can be connected in series and parallel at an upper portion of the cylindrical batteries 200 using a bus bar 210. The number of cylindrical batteries 200 can be increased or decreased depending on the capacity of the battery pack.

[0389] In each cylindrical battery 200, the terminal 172 may have a positive polarity and the flat surface 171a around the terminal 172 of the battery case 171 may have a negative polarity, or vice versa.

[0390] The plurality of cylindrical batteries 200 may be arranged in a plurality of columns and rows. Columns are provided in a vertical direction with respect to the drawing, and rows are provided in a left and right direction with respect to the drawing. Furthermore, to maximize space efficiency, the cylindrical batteries 200 may be arranged in a densest packing structure. The densest packing structure is formed when an equilateral triangle is formed by connecting the centers of the terminals 172 exposed from the battery case 171. The bus bar 210 connects the cylindrical batteries 200 arranged in the same column in parallel and connects the cylindrical batteries 200 arranged in two adjacent columns in series.

[0391] The busbar 210 may include a body portion 211, a plurality of first busbar terminals 212, and a plurality of second busbar terminals 213 for series and parallel connection. The body portion 211 may extend along the column of the cylindrical battery 200 between adjacent terminals 172. Alternatively, the body portion 211 may extend along the row of cylindrical batteries 1 and may be regularly curved, such as a zigzag shape.

[0392] The plurality of first busbar terminals 212 may extend from one side of the body portion 211 and may be electrically coupled to the terminal 172 of the cylindrical battery 200 located in the extending direction. The electrical connection between the first busbar terminal 212 and the terminal 172 may be achieved by laser welding, ultrasonic welding, or the like.

[0393] The plurality of second busbar terminals 213 may extend from the other side of the body portion 211 and may be electrically coupled to the flat surface 171a around the terminal 172 located in the extending direction. The electrical coupling between the second busbar terminal 213 and the flat surface 171a may be performed by laser welding, ultrasonic welding, or the like.

[0394] The body portion 211, the plurality of first busbar terminals 212, and the plurality of second busbar terminals 213 may be formed from a conductive metal plate. The metal plate may be, for example, an aluminum plate or a copper plate, but the present disclosure is not limited thereto. In a modified example, the body portion 211, the plurality of first busbar terminals 212, and the second busbar terminals 213 may be manufactured as separate pieces and then coupled together by welding or the like.

[0395] The cylindrical battery 200 of the present disclosure, as described above, has a structure in which resistance is minimized by increasing the welding area by means of the bending surface area F1 and F2, multiplexing current paths by means of the second current collector 176, minimizing a current path length, or the like. The AC resistance of the cylindrical battery 200, measured by a ohmmeter between the positive electrode and the negative electrode, namely, between the terminal 172 and the flat surface 171a around the terminal 172, can be about 4 milliohms or less, suitable for fast charging.The AC resistance of the cylindrical battery 200, measured by a resistance meter between the positive electrode and the negative electrode, namely between the terminal 172 and the flat surface 171a around the terminal 172, may be 4 milliohms or less, 3 milliohms or less, 2 milliohms or less, or 0.5 milliohms or less, and / or at least 0.5 milliohms or at least 1.0 milliohms.

[0396] Since, in the cylindrical battery 200 according to the present disclosure, the terminal 172 having a positive polarity and the flat surface 171a having a negative polarity are located in the same direction, it is easy to electrically connect the cylindrical batteries 200 using the bus bar 210.

[0397] In addition, since the terminal 172 of the cylindrical battery 200 and the flat surface 171a around the terminal 172 have a large area, the coupling portion of the bus bar 210 can be sufficiently secured to sufficiently reduce the resistance of the battery pack including the cylindrical battery 200.

[0398] The cylindrical battery can be used to manufacture a battery pack.

[0399] Fig. 16 is a diagram schematically showing a battery pack. The battery pack includes one or more cylindrical batteries as described above. The cylindrical batteries may be arranged in one or more columns. The cylindrical battery cells may be arranged such that their electrode terminals and the second end surfaces of the battery cans of the cylindrical battery cells are at the top. In other words, the electrode terminal and the outer surface of the bottom of the battery can of each cylindrical battery cell may be arranged to face upward.

[0400] With reference to Fig. 16, a battery pack 300 includes a unit in which cylindrical batteries 301 are electrically connected, and a pack case 302 for accommodating the unit. The cylindrical battery 301 may be any of the batteries according to the above embodiments (modifications). In the drawing, components such as a bus bar, a cooling unit, and an external terminal for electrically connecting the cylindrical batteries 301 are omitted for clarity.

[0401] The battery pack 300 may be mounted on a vehicle. The vehicle may be, for example, an electric vehicle, a hybrid electric vehicle, or a plug-in hybrid vehicle. The vehicle may include a four-wheel vehicle or a two-wheel vehicle.

[0402] Fig. 17 is a diagram schematically showing a vehicle using the battery pack 300 of Fig. 16 includes.

[0403] With reference to Fig.17, a vehicle V may include the battery pack 300 as described above. The vehicle V operates by receiving power from the battery pack 300.

[0404] When bending the uncoated portions exposed at both ends of the electrode assembly, the separator or the active material layer can be prevented from being damaged when the current collector is welded by sufficiently securing an area where the uncoated portion is overlapped in 10 or more layers in the radial direction of the electrode assembly.

[0405] Since the structure of the uncoated portion adjacent to the core of the electrode assembly is improved, the cavity in the core of the electrode assembly can be prevented from being blocked when the uncoated portion is bent. Thus, the electrolyte injection process and the welding process of the battery case and current collector can be easily performed.

[0406] Since the bending surface area of ​​the uncoated section is welded directly to the current collector instead of a strip-shaped electrode tab, it is possible to provide an electrode assembly with improved energy density and reduced resistance.

[0407] It is possible to provide a cylindrical battery having a structure that has low internal resistance and improves the welding strength between the current collector and the uncoated portion, and a battery pack and a vehicle including the cylindrical battery.

[0408] Item 1. An electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound on the basis of an axis to define a core and an outer circumference, wherein the first electrode includes an uncoated portion at a long side end thereof and exposed out from the separator along a winding axis direction of the electrode assembly, and a part of the uncoated portion is bent in a radial direction of the electrode assembly to form a bending surface region including overlapped layers of the uncoated portion, and in a partial region of the bending surface region, the number of stacked layers of the uncoated portion in the winding axis direction of the electrode assembly is 10 or more.

[0409] Item 2. The electrode assembly according to item 1, wherein, when the number of turns of the first electrode is defined as n1 and a value obtained by dividing a turn index k (a natural number from 1 to n1) at a k-th turn position by the number of the total number of turns n1 is defined as a relative radial position R1,k of the turn index k, an aspect ratio of a radial region of R1,k that satisfies a condition that the number of stacked layers of the uncoated portion is 10 or more is 30% or more based on a relative radial position range in which the uncoated portion is bent.

[0410] Item 3. The electrode assembly according to item 2, wherein the aspect ratio of the radial region of R1,k that satisfies a condition that the number of stacked layers of the uncoated portion is 10 or more is 30% to 85% based on the relative radial position range in which the uncoated portion is bent.

[0411] Item 4. The electrode assembly according to item 1, wherein the second electrode includes an uncoated portion at a long side end thereof and exposed out of the separator along the winding axis direction of the electrode assembly, and a part of the uncoated portion is bent in the radial direction of the electrode assembly to form a bending surface region including overlapped layers of the uncoated portion, and in a partial area of ​​the bending surface region, the number of stacked layers of the uncoated portion in the winding axis direction of the electrode assembly is 10 or more.

[0412] Item 5. The electrode assembly according to item 4, wherein, when the number of turns of the second electrode is defined as n2 and a value obtained by dividing a turn index k (a natural number from 1 to n2) at a k-th turn position by the number of the total number of turns n2 is defined as a relative radial position R2,k of the turn index k, an aspect ratio of a radial region of R2,k that satisfies a condition that the number of stacked layers of the uncoated portion is 10 or more is 30% or more based on a relative radial position range in which the uncoated portion is bent.

[0413] Item 6. The electrode assembly according to item 5, wherein the aspect ratio of the radial region of R2,k satisfying a condition that the number of stacked layers of the uncoated portion is 10 or more is 30% to 85% based on the relative radial position range in which the uncoated portion is bent.

[0414] Item 7. Electrode assembly according to item 2, wherein in the winding structure of the first electrode, the uncoated portion of a region from a relative radial position R1,1 of a 1-th winding turn to a first relative radial position R1,k* of a preset k*th winding turn has a smaller height than the uncoated portion of a region from a relative radial position R 1,k*+1 of a k*+1-th winding path to a relative radial position 1.

[0415] Item 8. The electrode assembly according to item 2, wherein in the winding structure of the first electrode, the uncoated portion of a region from a relative radial position R1,1 of a 1-th winding turn to a first relative radial position R1,k* of a preset k*th winding turn has a smaller height than the bending surface region formed by overlapping the bent uncoated portions.

[0416] Item 9. Electrode assembly according to item 2, wherein in the winding structure of the first electrode, the uncoated portion of a region from a relative radial position R1,1 of a 1-th winding turn to a first relative radial position R1,k* of a k*th winding turn is not bent towards the core of the electrode assembly.

[0417] Item 10. Electrode assembly according to item 5, wherein in the winding structure of the second electrode, the uncoated portion of a region from a relative radial position R2,1 of a 1-th winding turn to a first relative radial position R2,k* of a preset k*th winding turn has a smaller height than the uncoated portion of a region from a relative radial position R 2,k*+1 of a k*+1-th winding path to a relative radial position 1.

[0418] Item 11. The electrode assembly according to item 5, wherein in the winding structure of the second electrode, the uncoated portion of a region from a relative radial position R2,1 of a 1-th winding turn to a first relative radial position R2,k* of a preset k*th winding turn has a smaller height than the bending surface region formed by overlapping the bent uncoated portions.

[0419] Item 12. Electrode assembly according to item 5, wherein in the winding structure of the second electrode, the uncoated portion of a region from a relative radial position R2,1 of a 1-th winding turn to a first relative radial position R2,k* of a preset k*th winding turn is not bent towards the core of the electrode assembly.

[0420] Item 13. The electrode assembly of item 1 or 4, wherein the uncoated portion of the first electrode or the second electrode is divided into a plurality of segments that are independently bendable.

[0421] Item 14. The electrode assembly of item 13, wherein each of the plurality of segments has a geometric shape using a bending line thereof as a base, and the geometric shape is formed by connecting one or more straight lines, one or more curves, or a combination thereof.

[0422] Item 15. Electrode assembly according to item 14, wherein the geometric shape has a width that decreases gradually or continuously from the base to the top.

[0423] Item 16. The electrode assembly of item 15, wherein a lower interior angle of the geometric shape between the base and a side intersecting the base is 60 degrees to 85 degrees.

[0424] Item 17. The electrode assembly according to item 16, wherein the lower interior angles of the plurality of segments increase stepwise or gradually along a direction parallel to the winding direction of the electrode assembly.

[0425] Item 18. The electrode assembly according to item 14, wherein each of the plurality of segments has a geometric shape using a bending line thereof as a base, and when r is a radius of a winding path in which the segment is arranged based on a core center of the electrode assembly, L arcis an arc length of a winding path corresponding to a lower portion of the segment, and θ assumption a lower interior angle of the segment assuming that sides of a pair of segments arranged adjacent in the winding path with the radius of r, where an actual lower interior angle θ real of the pair of segments arranged adjacently satisfies the following formula: θ real > θ assumption θ assumption = 90° - 360°*( L arc / 2πr)*0.5.

[0426] Item 19. Electrode assembly according to item 18, wherein a circumferential angle corresponding to the arc length L arc of the winding pitch corresponding to the lower portion of the segment based on the core center of the electrode assembly is 45 degrees or less.

[0427] Item 20. Electrode assembly according to item 18, wherein when an overlap ratio of the segments arranged adjacently in the winding path with the radius of r with respect to the core center of the electrode assembly is determined using a formula (θ real / θ assumption -1), the overlap ratio of the segments is greater than 0 and equal to or less than 0.05.

[0428] Item 21. Electrode assembly according to item 14, wherein when a virtual circle is drawn passing through a pair of segments arranged adjacently in the winding path with the radius of r with respect to the core center of the electrode assembly, a pair of arcs passing through each segment overlap each other.

[0429] Item 22. The electrode assembly according to item 21, wherein, when a ratio of a length of the overlapping arc to a length of the arc passing through each segment is defined as an overlap ratio, the overlap ratio of the segment is greater than 0 and equal to or less than 0.05.

[0430] Item 23. Electrode assembly according to item 2, wherein in the winding structure of the first electrode, the uncoated portion of a region from a relative radial position R1,1 of a 1-th winding turn to a first relative radial position R1,k* of a k*th winding turn has a smaller height than the uncoated portion of a region from a relative radial position R 1,k*+1 of a k*+1-th winding path to a relative radial position 1 and is not bent towards the core.

[0431] Item 24. Electrode assembly according to item 23, wherein a length of the first electrode corresponding to the range from the relative radial position R1,1 to the first relative radial position R1,k* is 1% to 30%, in relation to a length of the first electrode corresponding to the range from the relative radial position R 1,k*+1 to the relative radial position 1.

[0432] Item 25. Electrode assembly according to item 2, wherein in the winding structure of the first electrode a bending length fd 1,k*+1 of the uncoated section at a relative radial position R 1,k*+1 of a k*+1-th winding turn is shorter than a radial length from a relative radial position R1,1 of a 1-th winding turn to a relative radial position R1,k* of a k*th winding turn.

[0433] Item 26. Electrode assembly according to item 2, wherein in the winding structure of the first electrode, when a radius of the core of the electrode assembly is taken as rc is defined as a range from a center of the core to 0.90 r c is not blocked by a bent portion of the uncoated portion located in a range of a relative radial position R 1,k*+1 of a k*+1-th winding path to a relative radial position 1.

[0434] Item 27. Electrode assembly according to item 26, wherein a bending length fd 1,k*+1 of the uncoated section at a relative radial position R 1,k*+1 of a k*+1-th winding path, the radius r c of the core and a distance d 1,k*+1 from a center of the electrode assembly to the relative radial position R 1,k*+1 satisfy the following formula: fd 1,k*+1 + 0.90* r c ≤ d 1,k*+1 .

[0435] Item 28. Electrode assembly according to item 5, wherein in the winding structure of the second electrode, the uncoated portion of a region from a relative radial position R2,1 of a 1-th winding turn to a first relative radial position R2,k* of a preset k*th winding turn has a smaller height than the uncoated portion of a region from a relative radial position R 2,k*+1 of a k*+1-th winding path to a relative radial position 1 and is not bent towards the core.

[0436] Item 29. Electrode assembly according to item 28, wherein in relation to a length of the second electrode corresponding to the range of the relative radial position R 2,k*+1 to the relative radial position 1, a length of the second electrode corresponding to the range from the relative radial position R2,1 to the first relative radial position R2,k* is 1% to 30%.

[0437] Item 30. Electrode assembly according to item 5, wherein in the winding structure of the second electrode a bending length fd 2,k*+1 of the uncoated section at a relative radial position R 2,k*+1 of a k*+1-th winding turn is shorter than a radial length from a relative radial position R2,1 of a 1-th winding turn to a relative radial position R1,k* of a k*th winding turn.

[0438] Item 31. Electrode assembly according to item 5, wherein in the winding structure of the second electrode, when a radius of the core of the electrode assembly is taken as r c is defined as a range from a center of the core to 0.90 r c is not blocked by a bent portion of the uncoated portion of the second electrode located in a range of a relative radial position R 2,k*+1 of a k*+1-th winding path to a relative radial position 1.

[0439] Item 32. Electrode assembly according to item 31, wherein a bending length fd 2,k*+1 of the uncoated section at a relative radial position R 2,k*+1 of a k*+1-th winding path, the radius r c of the core and a distance d 2,k*+1 from a center of the electrode assembly to the relative radial position R 2,k*+1 satisfy the following formula: fd 2,k*+1 + 0.90* r c ≤ d 2,k*+1 .

[0440] Item 33. Electrode assembly according to item 2, wherein in the winding structure of the first electrode, the uncoated portion of a region of a relative radial position R 1,k*+1 of a k*+1-th winding turn to a second relative radial position R1,k@ of a preset k@-th winding turn into a plurality of segments whose heights increase gradually or stepwise along a direction parallel to the winding direction.

[0441] Item 34. Electrode assembly according to item 33, wherein a radial length of the region of the relative radial position R 1,k*+1 to the second relative radial position R1,k@ is 1% to 56% compared to a radius of the winding structure of the first electrode excluding the core of the electrode assembly.

[0442] Item 35. Electrode assembly according to item 2, wherein in the winding structure of the first electrode, the uncoated portion of a region of a relative radial position R 1,k@+1 a preset k@+1-th winding pitch to a relative radial position 1 is divided into a plurality of segments, and the plurality of segments have substantially the same height from the relative radial position R 1,k@+1 to the relative radial position 1.

[0443] Item 36. Electrode assembly according to item 5, wherein in the winding structure of the second electrode, the uncoated portion of a region of a relative radial position R 2,k*+1 of a k*+1-th winding turn to a second relative radial position R2,k@ of a preset k@-th winding turn into a plurality of segments whose heights increase stepwise or gradually along a direction parallel to the winding direction.

[0444] Item 37. Electrode assembly according to item 36, wherein a radial length of the region of the relative radial position R 2,k*+1 to the second relative radial position R2,k@ in relation to a radius of the winding structure of the second electrode excluding the core of the electrode assembly is 1% to 56%.

[0445] Item 38. Electrode assembly according to item 5, wherein in the winding structure of the second electrode, the uncoated portion of the second electrode of a region of a relative radial position R 2,k@+1 of a k@+1-th winding path to a relative radial position 1 is divided into a plurality of segments, and the plurality of segments height from the relative radial position R 2,k@+1 to the relative radial position 1 is essentially the same.

[0446] Item 39. The electrode assembly according to item 1, wherein in the winding structure of the first electrode, the uncoated portion bent in the radial direction of the electrode assembly is divided into a plurality of segments that are independently bendable, and at least a height of the plurality of segments in the winding axis direction and / or a width thereof in the winding direction individually or in groups gradually or stepwise increases along a direction parallel to the winding direction.

[0447] Item 40. The electrode assembly according to item 4, wherein in the winding structure of the second electrode, the uncoated portion bent in the radial direction of the electrode assembly is divided into a plurality of segments that are independently bendable, and at least a height of the plurality of segments in the winding axis direction and / or a width thereof in the winding direction individually or in groups gradually or stepwise increases along a direction parallel to the winding direction.

[0448] Item 41. The electrode assembly according to item 13, wherein each of the plurality of segments satisfies at least one condition including a condition related to a width of 1 to 11 mm in the winding direction; a condition related to a height of 2 to 10 mm in the winding axis direction; and a condition related to a separation pitch of 0.05 mm to 1 mm in the winding direction.

[0449] Item 42. The electrode assembly according to item 13, wherein a cut groove is arranged between the plurality of segments, and a predetermined gap is provided between a bottom of the cut groove and the active material layer of the first electrode or the second electrode.

[0450] Item 43. Electrode assembly according to item 32, wherein the gap has a length of 0.2 mm to 4 mm.

[0451] Item 44. The electrode assembly according to item 13, wherein the plurality of segments forms a plurality of segment groups along the winding direction of the electrode assembly, and segments belonging to the same segment group are substantially equal in at least one of a width in the winding direction, a height in the winding axis direction, and a separation pitch in the winding direction.

[0452] Item 45. The electrode assembly according to item 44, wherein the segments belonging to the same segment group are configured such that at least one of the width in the winding direction, the height in the winding axis direction, and the separation pitch in the winding direction gradually or stepwise increases along a direction parallel to the winding direction of the electrode assembly.

[0453] Item 46. Electrode assembly according to item 44, wherein at least a portion of the plurality of segment groups is arranged on the same winding turn of the electrode assembly.

[0454] Item 47. The electrode assembly according to item 1, wherein the bending surface area formed by the uncoated portion of the first electrode includes, from the outer periphery of the electrode assembly to the core thereof, a stack number increasing area and a stack number uniform area, the stack number increasing area being defined as an area where the number of stacked layers of the uncoated portion increases toward the core of the electrode assembly, and the stack number uniform area being defined as an area from a radial position where the increase in the number of stacked layers of the uncoated portion stops to a radial position where the uncoated portion starts to bend, and a radial length of the stack number uniform area compared to a radial length from a winding turn where the uncoated portion starts to bend to a winding turn,where the uncoated section terminates the bending, is 30% or more.

[0455] Item 48. The electrode assembly according to Item 5, wherein the bending surface region formed by the uncoated portion of the second electrode includes a stack number increasing region and a stack number uniform region from the outer periphery of the electrode assembly to the core thereof, wherein the stack number increasing region is defined as a region in which the number of stacked layers of the uncoated portion increases toward the core of the electrode assembly, and the stack number uniform region is defined as a region from a radial position at which the increase in the number of stacked layers of the uncoated portion stops to a radial position at which the uncoated portion starts to bend, and a radial length of the stack number uniform region is relative to a radial length from a winding turn where the uncoated portion starts to bend to a winding turn,where the uncoated section terminates the bending, is 30% or more.

[0456] Item 49. The electrode assembly according to item 4, wherein the first electrode and the second electrode have a thickness of 80 µm to 250 µm and an interval of the uncoated portions located adjacent to winding turns in the radial direction of the electrode assembly is 200 µm to 500 µm.

[0457] Item 50. The electrode assembly of item 1, wherein the uncoated portion of the first electrode has a thickness of 10 µm to 25 µm.

[0458] Item 51. The electrode assembly of item 4, wherein the uncoated portion of the second electrode has a thickness of 5 µm to 20 µm.

[0459] Item 52. Electrode assembly according to item 1, wherein in the portion of the bending surface region formed by the uncoated portion of the first electrode, a total stack thickness of overlapping layers of the uncoated portion is 100 µm to 975 µm.

[0460] Item 53. The electrode assembly according to item 52, wherein the uncoated portion of the first electrode is divided into a plurality of segments that are independently bendable, the first electrode including a height-variable region in which heights of segments are variable and a height-uniform region in which heights of segments are uniform, and wherein, in a region formed by bending the segments included in the height-uniform region along the radial direction of the electrode assembly in the bending surface region, a ratio of a stack thickness of the uncoated portion of the bending surface region to the height of the segment is 1.0% to 16.3%.

[0461] Item 54. Electrode assembly according to item 4, wherein in the portion of the bending surface region formed by the uncoated portion of the second electrode, a total stack thickness of overlapping layers of the uncoated portion is 50 µm to 780 µm.

[0462] Item 55. The electrode assembly according to item 54, wherein the uncoated portion of the second electrode is divided into a plurality of segments that are independently bendable, the second electrode including a height-variable region in which heights of segments are variable and a height-uniform region in which heights of segments are uniform, and wherein, in a region formed by bending the segments included in the height-uniform region along the radial direction of the electrode assembly in the bending surface region, a ratio of a stack thickness of the uncoated portion of the bending surface region to the height of the segment is 0.5% to 13.0%.

[0463] Item 56. An electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound on the basis of an axis to define a core and an outer periphery, the first electrode including a first uncoated portion at a long side end thereof and exposed out from the separator along a winding axis direction of the electrode assembly, and a part of the first uncoated portion is bent in a radial direction of the electrode assembly to form a first bending surface region, and in a partial region of the first bending surface region, a stacking thickness of the first uncoated portion is 100 μm to 975 μm.

[0464] Item 57. The electrode assembly according to item 56, wherein the first uncoated portion of the first electrode is divided into a plurality of segments that are independently bendable, the first electrode including a height-variable region in which heights of segments are variable and a height-uniform region in which heights of segments are uniform, and wherein, in a region formed by bending the segments included in the height-uniform region along the radial direction of the electrode assembly in the bending surface region, a ratio of a stack thickness of the uncoated portion of the bending surface region to the height of the segment is 1.0% to 16.3%.

[0465] Item 58. The electrode assembly according to item 56, wherein the second electrode includes a second uncoated portion at a long side end thereof and exposed out of the separator along the winding axis direction of the electrode assembly, wherein a part of the second uncoated portion is bent in the radial direction of the electrode assembly to form a second bending surface region, and wherein in a partial region of the second bending surface region, a stack thickness of the second uncoated portion is 50 µm to 780 µm.

[0466] Item 59. The electrode assembly according to item 58, wherein the second uncoated portion of the second electrode is divided into a plurality of segments that are independently bendable, the second electrode including a height-variable region in which heights of segments are variable and a height-uniform region in which heights of segments are uniform, and wherein, in a region formed by bending the segments included in the height-uniform region along the radial direction of the electrode assembly in the bending surface region, a ratio of a stack thickness of the uncoated portion of the bending surface region to the height of the segment is 0.5% to 13.0%.

[0467] Item 60. A battery comprising: an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound on an axis basis to define a core and an outer periphery, wherein at least one of the first electrode and the second electrode includes an uncoated portion at a long side end thereof and is exposed from the separator along a winding axis direction of the electrode assembly, and at least a part of the uncoated portion is bent in a radial direction of the electrode assembly to form a bending surface region, and in a partial area of ​​the bending surface region, the number of stacked layers of the uncoated portion is 10 or more; a battery case configured to accommodate the electrode assembly and electrically connected to one of the first electrode and the second electrode to have a first polarity;a sealing body configured to seal an open end of the battery case; a terminal electrically connected to the other of the first electrode and the second electrode to have a second polarity and configured to have an outwardly exposed surface; and a current collector welded to the bending surface region and electrically connected to one of the battery case and the terminal, wherein the welding region of the current collector overlaps with the bending surface region in which the number of stacked layers of the uncoated portion is 10 or more.

[0468] Item 61. The battery according to Item 60, wherein the first electrode includes a first uncoated portion on the long side thereof and is exposed from the separator along the winding axis direction of the electrode assembly, and when the number of turns of the first electrode is defined as n1 and a value obtained by dividing a turn index k (a natural number from 1 to n1) at a k-th turn position by the number of the total number of turns n1 is defined as a relative radial position R1,k of the turn index k, an aspect ratio of a radial area of ​​R1,k that satisfies a condition that the number of stacked layers of the first uncoated portion is 10 or more is 30% or more based on a relative radial position range in which the first uncoated portion is bent.

[0469] Item 62. The battery according to Item 60, wherein the second electrode includes a second uncoated portion on the long side thereof and exposed out from the separator along the winding axis direction of the electrode assembly, and when the number of turns of the second electrode is defined as n2 and a value obtained by dividing a turn index k (a natural number from 1 to n2) at a k-th turn position by the number of the total number of turns n2 is defined as a relative radial position R2,k of the turn index k, an aspect ratio of a radial area of ​​R2,k that satisfies a condition that the number of stacked layers of the second uncoated portion is 10 or more is 30% or more based on a relative radial position range in which the second uncoated portion is bent.

[0470] Item 63. Battery according to Item 60, wherein the welding area of ​​the current collector overlaps with the bending surface area in which the number of stacked layers of the uncoated portion is 10 or more by 50% or more.

[0471] Item 64. Battery according to Item 63, where the welding strength of the current collector is in the range of 2 kgf / cm 2 or more.

[0472] Item 65. A battery comprising: an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound on an axis basis to define a core and an outer circumference, the first electrode including a first uncoated portion at a long side end thereof and exposed from the separator along a winding axis direction of the electrode assembly, and a part of the first uncoated portion is bent in a radial direction of the electrode assembly to form a first bending surface region, and in a partial region of the first bending surface region, a stacking thickness of the first uncoated portion is 100 μm to 975 μm; a battery case configured to accommodate the electrode assembly and electrically connected to one of the first electrode and the second electrode to have a first polarity;a sealing body configured to seal an open end of the battery case; a terminal electrically connected to the other of the first electrode and the second electrode to have a second polarity and configured to have an outwardly exposed surface; and a first current collector welded to the first bending surface region and electrically connected to one of the battery case and the terminal, wherein the welding region of the first current collector overlaps with the portion of the first bending surface region in which the stack thickness of the first uncoated portion is 100 µm to 975 µm.

[0473] Item 66. The battery according to item 65, wherein the first uncoated portion of the first electrode is divided into a plurality of segments that are independently bendable, the first electrode including a height-variable region in which heights of segments are variable and a height-uniform region in which heights of segments are uniform, and wherein, in a region formed by bending the segments included in the height-uniform region along the radial direction of the electrode assembly in the first bending surface region, a ratio of a stack thickness of the uncoated portion of the first bending surface region to the height of the segment is 1.0% to 16.3%.

[0474] Item 67. Battery according to Item 65, wherein the welding strength of the first current collector is in the range of 2 kgf / cm 2 or more.

[0475] Item 68. The battery according to item 65, wherein the second electrode includes a second uncoated portion at a long side end thereof and exposed out from the separator along the winding axis direction of the electrode assembly, wherein a part of the second uncoated portion is bent in the radial direction of the electrode assembly to form a second bending surface region, and wherein, in a partial region of the second bending surface region, a stacking thickness of the second uncoated portion is 50 μm to 780 μm, the battery includes a second current collector welded to the second bending surface region and electrically connected to one of the battery case and the terminal, and wherein the welding region of the second current collector overlaps with the partial region of the second bending surface region in which the stacking thickness of the second uncoated portion is 50 μm to 780 μm.

[0476] Item 69. The battery according to item 68, wherein the second uncoated portion of the second electrode is divided into a plurality of segments that are independently bendable, the second electrode including a height-variable region in which heights of segments are variable and a height-uniform region in which heights of segments are uniform, and wherein, in a region formed by bending the segments included in the height-uniform region along the radial direction of the electrode assembly in the second bending surface region, a ratio of a stack thickness of the uncoated portion of the second bending surface region to the height of the segment is 0.5% to 13.0%. Item 70. The battery according to item 68, wherein the welding strength of the second current collector is in the range of 2 kgf / cm 2 or more.

[0477] Item 71. A battery according to item 65, wherein the welding area of ​​the first current collector overlaps with the portion of the first bending surface area in which the stack thickness of the first uncoated section is 100 µm to 975 µm by 50% or more.

[0478] Item 72. A battery according to item 68, wherein the welding area of ​​the second current collector overlaps with the portion of the second bending surface area in which the stack thickness of the second uncoated portion is 50 µm to 780 µm by 50% or more.

[0479] Item 73. Battery pack comprising the battery according to any of items 60 to 72.

[0480] Item 74. Vehicle comprising the battery pack according to Item 73.

[0481] The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are intended for purposes of illustration only, since various changes and modifications within the scope of the disclosure will become apparent to those skilled in the art from this detailed description. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 6,677,082

[0173] US 6,680,143

[0173]

Claims

[1] Battery (190), comprising: an electrode assembly (110) in which a first electrode (10; 11), a second electrode (10; 11), and a separator (12) arranged therebetween are wound with respect to an axis and thereby define a core (C) and an outer periphery, wherein at least one of the first electrode (10; 11) and the second electrode (10; 11) has an uncoated portion (43) adjacent to an edge of the respective electrode (10; 11), wherein the uncoated portion (43) extends beyond the separator (12) along a winding axis direction of the electrode assembly (110), and wherein at least a part of the uncoated portion (43) is bent in a radial direction of the electrode assembly (110) to form a bending surface region (F), wherein in a partial region of the bending surface region (F), the number of stacked layers of the uncoated portion (43) is 10 or more; a battery case (171) configured to receive the electrode assembly (110) and electrically connected to one of the first electrode (10; 11) and the second electrode (10; 11) and thereby having a first polarity; a closure body (178) configured to close an open end of the battery case (171); a terminal (172) mounted through a hole in an end of the battery case (171) opposite the open end and electrically connected to the other of the first electrode (10; 11) and the second electrode (10; 11), thereby having a second polarity and configured to have an outwardly exposed surface, the terminal (172) comprising an exposed terminal portion (172a) and an insertion portion (172b), the exposed terminal portion (172a) being exposed to the outside at the end of the battery case (171) opposite the open end, and the insertion portion (172b) being riveted to an inner surface of the battery case (171) at the end of the battery case (171) opposite the open end; a seal (173) made of an insulating material arranged between the battery case (171) and the terminal (172); a current collector (176) welded to the bending surface region (F) and electrically connected to one of the battery case (171) and the terminal (172), wherein the welding area of ​​the current collector (176) overlaps the bending surface area (F) in which the number of stacked layers of the uncoated portion (43) is 10 or more, wherein the partial region of the bending surface region (F) extends circularly around a winding axis or is an annular region. [2] Battery according to claim 1, wherein the first electrode (10; 11) has a first uncoated portion (43) adjacent to an edge of the first electrode (10; 11), the second uncoated portion (43) extending along the winding axis direction of the electrode assembly (110) beyond the separator (12), and wherein the number of total winding turns of the first electrode (10; 11) is defined as n1, and wherein a value obtained by dividing a winding turn index k (a natural number from 1 to n1) at a k-th winding turn position by the number of total winding turns n1 is defined as a relative radial position R 1,k of the winding turn index k, where a length ratio of a radial area of ​​R 1,k which satisfies a condition that the number of stacked layers of the first uncoated portion (43) is 10 or more, is 30% or more with respect to a relative radial position range in which the first uncoated portion (43) is bent. [3] Battery according to claim 1 or 2, wherein the second electrode (10; 11) has a second uncoated portion (43) adjacent to an edge of the second electrode (10; 11), the second uncoated portion (43) extending beyond the separator (12) along the winding axis direction of the electrode assembly (110), and wherein the number of total winding turns of the second electrode (10; 11) is defined as n2, and wherein a value obtained by dividing a winding turn index k (a natural number from 1 to n2) at a k-th winding turn position by the number of total winding turns n2 is defined as a relative radial position R 2,k of the winding turn index k, where a length ratio of a radial area of ​​R 2,kwhich satisfies a condition that the number of stacked layers of the second uncoated portion (43) is 10 or more, is 30% or more with respect to a relative radial position range in which the second uncoated portion (43) is bent. [4] Battery according to one of claims 1 to 3, wherein the welding area of ​​the current collector (176) overlaps the bending surface area (F) in which the number of stacked layers of the uncoated portion (43) is 10 or more by 50% or more, wherein the welding strength of the current collector (176) is in a range of 0.196133 MPa (2 kgf / cm 2 ) or more. [5] Battery, comprising: an electrode assembly (110) in which a first electrode (10; 11), a second electrode (10; 11), and a separator (12) arranged therebetween are wound with respect to an axis and thereby define a core (C) and an outer periphery, wherein the first electrode (10; 11) has a first uncoated portion (43) adjacent to an edge of the respective electrode (10; 11), wherein the first uncoated portion (43) extends beyond the separator (12) along a winding axis direction of the electrode assembly (110), and wherein a part of the first uncoated portion (43) is bent in a radial direction of the electrode assembly (110) to form a first bending surface region (F), wherein in a partial region of the first bending surface region (F), a stack thickness of the overlapping layers of the first uncoated portion (43) is 100 µm to 975 µm, a battery case (171) configured to receive the electrode assembly (110) and electrically connected to one of the first electrode (10; 11) and the second electrode (10; 11) and thereby having a first polarity; a closure body (178) configured to close an open end of the battery case (171); a terminal (172) mounted through a hole in an end of the battery case (171) opposite the open end and electrically connected to the other of the first electrode (10; 11) and the second electrode (10; 11), thereby having a second polarity and configured to have an outwardly exposed surface, the terminal (172) comprising an exposed terminal portion (172a) and an insertion portion (172b), the exposed terminal portion (172a) being exposed to the outside at the end of the battery case (171) opposite the open end, and the insertion portion (172b) being riveted to an inner surface of the battery case (171) at the end of the battery case (171) opposite the open end; a seal (173) made of an insulating material arranged between the battery case (171) and the terminal (172); a first current collector (176) welded to the first bending surface region (F) and electrically connected to one of the battery case (171) and the terminal (172), wherein the welding region of the first current collector (176) overlaps the partial region of the first bending surface region (F) in which the stack thickness of the first uncoated section (43) is 100 µm to 975 µm, wherein the partial region of the bending surface region (F) extends circularly around a winding axis or is an annular region. [6] Battery according to claim 5, wherein the first uncoated portion (43) of the first electrode (10; 11) is divided into a plurality of separate tabs (61) which are independently bendable, the first electrode (10; 11) having a height-variable region in which the heights of the separate tabs (61) are variable, and a height-uniform region in which the heights of the separate tabs (61) are uniform, and in a region formed by bending the segments included in the height-uniform region along the radial direction of the electrode assembly (110) in the first bending surface region (F), a ratio of a stack thickness of the uncoated portion (43) to the height of the separate tab (61) is 1.3% to 16.0%. wherein the welding strength of the first current collector (144) is in a range of 0.196133 MPa (2 kgf / cm 2 ) or more. [7] Battery according to claim 5 or 6, wherein the second electrode (10; 11) has a second uncoated portion (43) adjacent to an edge of the second electrode (10; 11), wherein the second uncoated portion (43) extends along the winding axis direction of the electrode assembly (110) beyond the separator (12), wherein a part of the second uncoated portion (43) is bent in the radial direction of the electrode assembly (110) and thereby forms a second bending surface region (F), and in a partial region of the second bending surface region (F), a stack thickness of the second uncoated portion (43) is 50 µm to 780 µm, the battery comprises a second current collector (145) welded to the second bending surface region (F) and electrically connected to one of the battery case (171) and the terminal (172), and the welding region of the second current collector (145) overlaps the partial region of the second bending surface region (F) in which the stack thickness of the second uncoated section (43) is 50 µm to 780 µm. [8] Battery according to claim 7, wherein the second uncoated portion (43) of the second electrode (10; 11) is divided into a plurality of separate tabs (61) which are independently bendable, the second electrode (10; 11) having a height-variable region in which the heights of the separate tabs (61) are variable, and a height-uniform region in which the heights of the separate tabs (61) are uniform, and in a region formed by bending the segments included in the height-uniform region along the radial direction of the electrode assembly (110) in the second bending surface region (F), a ratio of a stack thickness of the second uncoated portion (43) to the height of the separate tab (61) is 0.5% to 13.0%. wherein the welding strength of the second current collector (145) is in a range of 0.196133 MPa (2 kgf / cm 2 ) or more, and / or wherein the welding region of the second current collector (145) overlaps the partial region of the second bending surface region (F) in which the stack thickness of the second uncoated portion (43) is 50 µm to 780 µm by 50% or more. [9] The battery according to claim 7, wherein the welding region of the first current collector (144) overlaps the portion of the first bending surface region (F) in which the stack thickness of the first uncoated portion (43) is 100 µm to 975 µm by 50% or more. [10] Battery pack (300) comprising the battery according to any one of claims 1 to 9. [11] Vehicle (V) comprising the battery pack (300) according to claim 10.

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