Electrode assembly, cylindrical battery, and battery pack and vehicle including same

Abstract

The invention discloses an electrode assembly, a cylindrical battery, a battery pack and a vehicle. The electrode assembly has a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound. The outermost holding portion of the electrode assembly is a holding portion of the first electrode. The winding end portion of the separator further extends from the winding end portion of the first electrode holding portion. The fixing member is attached to the winding end portion of the diaphragm in the axial direction from a point spaced apart from the axial end portion of the diaphragm. When the winding end corner portion of the diaphragm is folded to the maximum extent with the axial end portion of the fixing member as a folding bias point such that the outer surface thereof faces the outer peripheral surface, the winding end corner portion of the first electrode holding portion is not exposed to the outside.

Description

Technical Field

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

[0002] This application claims priority from Korean Patent Application No. 10-2023-0108388 filed in Korea on August 18, 2023, and Korean Patent Application No. 10-2024-0108559 filed in Korea on August 13, 2024, the disclosures of which are incorporated herein by reference. Background Art

[0003] Secondary batteries, which are easily applicable to various product groups and have electrical characteristics such as high energy density, are commonly used not only in portable devices but also in electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by an electric drive source.

[0004] These secondary batteries are attracting attention as new energy sources for improving eco-friendliness and energy efficiency because they have a primary advantage of being able to significantly reduce the use of fossil fuels and a secondary advantage of not generating byproducts from the use of energy.

[0005] Secondary batteries currently widely used in the art include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc. A unit secondary battery (i.e., a unit cell) has an operating voltage of about 2.5V to 4.5V. Therefore, when a higher output voltage is required, a battery pack can be configured by connecting multiple batteries in series. In addition, depending on the charge / discharge capacity required for the battery pack, multiple batteries can be connected in parallel to form a battery pack. Therefore, the number of batteries included in the battery pack and the form of electrical connection can be set differently according to the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, as a unit secondary battery, a cylindrical battery, a rectangular battery, and a pouch-type battery are known. In the case of a cylindrical battery, a diaphragm serving as an insulator is interposed between the positive electrode and the negative electrode, and it is wound to form an electrode assembly in the form of a roll core that is inserted into a battery casing (can) to constitute a battery. In addition, a strip-shaped electrode tab may be connected to the uncoated portion of each of the positive and negative electrodes, and the electrode tab electrically connects the electrode assembly and the electrode terminal exposed to the outside. For reference, the positive terminal is a cover of a sealing body that seals the opening of the battery casing, and the negative terminal is the battery casing. However, according to a conventional cylindrical battery having such a structure, since the current is concentrated in the strip-shaped electrode tab connected to the uncoated portion of the positive electrode and / or the uncoated portion of the negative electrode, the current collection efficiency is poor due to large resistance and high heat generation.

[0007] For small cylindrical batteries with a form factor of 1865 (diameter: 18mm, height: 65mm) or a form factor of 2170 (diameter: 21mm, height: 70mm), resistance and heat are not major issues. However, when the form factor is increased to apply cylindrical batteries to electric vehicles, the cylindrical batteries may catch fire while generating a lot of heat around the electrode joints during the fast charging process.

[0008] To solve this problem, a cylindrical battery (so-called jointless 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 located at the top and bottom of a jelly-roll type electrode assembly, respectively, and the current collector is welded to the uncoated portion to improve the current collection efficiency.

[0009] Figures 1 to 3 It is a diagram showing the process of manufacturing a jointless cylindrical battery. Figure 1 The structure of the electrode is shown. Figure 2 The process of winding the electrode is shown, and Figure 3 The process of welding the current collector to the bent surface area of ​​the uncoated portion is shown.

[0010] Reference Figures 1 to 3 The positive electrode 10 and the negative electrode 11 include a sheet-shaped current collector 20 having a pair of short sides and a pair of long sides, and a coating portion 21 formed of an active material layer coated on the surface of the current collector 20. In addition, the positive electrode 10 and the negative electrode 11 include an uncoated portion 22 on one long side along the winding direction X.

[0011] By combining the positive electrode 10 and the negative electrode 11 as Figure 2 As shown in the figure, the positive electrode 10 and the negative electrode 11 are sequentially stacked together with two separators 12, and then wound in one direction X to manufacture the electrode assembly A. The stacking order of the positive electrode 10 and the negative electrode 11 can be opposite to the order shown in the figure. The uncoated portions of the positive electrode 10 and the negative electrode 11 are arranged in opposite directions based on the winding axis direction of the electrode assembly A, and extend and are exposed to the outside of the separator 12.

[0012] 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 facilitate smooth folding, the uncoated portion 10a of the positive electrode 10 and the uncoated portion 11a of the negative electrode 11 can be divided into multiple independently foldable segments. Thereafter, the current collectors 30 and 31 are respectively connected to the folded uncoated portions 10a and 11a by welding.

[0013] The electrode tabs are not individually connected to the positive electrode uncoated portion 10a and the negative electrode uncoated portion 11a. The current collectors 30 and 31 are connected to the external electrode terminals, and a current path with a large cross-sectional area is formed along the winding axis direction (see arrow) of the electrode assembly A. This has the advantage of reducing the resistance of the battery. This is because the resistance is inversely proportional to the cross-sectional area of ​​the path through which the current flows.

[0014] At the same time, the outer periphery of the electrode assembly A is wrapped with a separator to prevent the coating portion of the outermost electrode from being exposed. However, during the process of unloading the electrode assembly A from the winding device, transporting the electrode assembly A between assembly processes, and inserting the electrode assembly A into the battery case, the winding end corners of the separator are folded outward, so that the winding end (especially the corner) of the outermost coating portion can be exposed to the outside.

[0015] Figure 4 is a graph showing the winding end angle (S) of the separator S when it is wound on the outer periphery of the electrode assembly A according to the prior art. c ) is folded outward, exposing the coating portion of the outermost electrode E (E coating )'s state.

[0016] Reference Figure 4 The outermost electrode E of the electrode assembly A is surrounded by a separator S. This is to prevent the electrode E from being exposed to the outside. Therefore, the winding end (S end ) along the winding direction than the winding end of the electrode E (E end ) extends further. As a result, the coating portion (E coating ) are not exposed to the outside.

[0017] By attaching the fixing member T to the wound end (S end ) to fix the winding end of the diaphragm S (S end ). The fixing member T prevents the rolled state of the electrode assembly A from being released. The adhesive tape is mainly used as the fixing member T. However, in the process of processing the electrode assembly A to assemble a cylindrical battery, the rolled end corner (S) of the separator S can be folded outward with the end of the fixing member T as a folding bias point. c In this case, the winding end angle (S c ) faces the outer periphery of the electrode assembly A. In addition, if the winding end (S end ) and the winding end of electrode E (E end ) is not enough, the coating portion (E coatig ) is exposed to the outside.

[0018] If the coating portion of the electrode E (E coatig ) is exposed, then when vibration or impact is applied to the electrode assembly A, the active material particles are coatig ) falls off, thereby increasing the risk of low voltage. In addition, the uncoated portion (E uncoated ) is exposed at the upper portion of the electrode assembly A. In addition, the uncoated portion (E uncoated ) can be divided into multiple segments (E flag) to make the folding smooth. In this case, when the winding end angle (S c ) When folded, the coating part (E coatig ) near the segment (E' flag ) can also be combined with the winding end angle (S c ) are folded outwards together, and segment (E' flag ) can be connected to the outer surface of the coating portion (E coatig ) is in contact with the exposed surface of the coating portion (E). A cylindrical battery manufactured using the electrode assembly A in this state may catch fire or explode during the activation process or subsequent charge / discharge cycles. This is because when the coating portion (E coatig When an internal short circuit occurs at the point where the ) and segment (E'flag) contact each other, the internal temperature and pressure of the cylindrical battery rise rapidly.

[0019] In order to solve the above problem, the winding end (S end ) and the winding end of electrode E (E end ) can be significantly increased with a safety margin or more, or the periphery of the electrode assembly A can be additionally wound with the separator S one or more turns. However, this method leads to an increase in the amount of separator used, thereby increasing the manufacturing cost of the cylindrical battery. In addition, the end portion of the separator S in the axial direction Y and the coating portion (E coating ) may increase the distance between the axial ends of the electrode assembly A. However, this approach reduces the total height of the coating portion (E coating ) height ratio, thereby reducing the energy density of cylindrical batteries. Summary of the Invention

[0020] Technical issues

[0021] The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure aims to provide an electrode assembly with an improved structure, wherein the attachment position of the fixing member to the winding end of the diaphragm is optimized so that in an electrode assembly having a jointless structure on at least one of the positive electrode and the negative electrode, even when the winding end angle of the diaphragm is folded outward, the coating portion of the outermost electrode covered by the diaphragm will not be exposed to the outside.

[0022] The present disclosure also aims to provide a battery including an electrode assembly having an improved structure, a battery pack including the battery, and a vehicle including the battery pack.

[0023] The technical objectives to be solved by the present disclosure are not limited to the above-mentioned problems, and other objectives not mentioned herein will be clearly understood by those skilled in the art from the following disclosure.

[0024] Technical Solution

[0025] First, the inventors of the present disclosure have confirmed through a lot of trial and error that in an electrode assembly having a jointless structure on at least one of the positive and negative electrodes, there is a minimum value of the folding angle when the winding end angle of the separator is folded outward using the end of the fixing member as a folding bias point.

[0026] In the present disclosure, a jointless structure refers to a structure in which the uncoated portion provided at the end of the long side along the winding direction of the electrode itself serves as a joint without separately attaching a joint to the uncoated portion of the electrode. The uncoated portion may be divided into at least a plurality of segments, or alternatively, the uncoated portion may not be divided.

[0027] In addition, the inventors of the present disclosure have confirmed through continuous research and development that by optimizing the design of the attachment position of the fixing member by utilizing the distance between the winding end of the diaphragm and the winding end of the outermost coating portion along the winding direction, the distance between the end of the diaphragm and the end of the outermost coating portion relative to the axial direction of the electrode assembly, and the minimum folding angle of the winding end angle of the diaphragm, the coating portion of the outermost electrode can be fundamentally prevented from being exposed even when the winding end angle of the diaphragm is folded outward to the maximum extent using the end of the fixing member as a folding bias point.

[0028] In one aspect of the present disclosure, an electrode assembly may be provided, wherein a first electrode and a second electrode and a separator interposed therebetween are wound around an axis to define a core and a periphery, the first electrode and the second electrode having short sides and long sides, and including a coated portion and an uncoated portion along the long side direction.

[0029] In the electrode assembly, the outermost coating portion may be the coating portion of the first electrode. A winding end of the coating portion of the first electrode may extend further in a winding direction than a winding end of the coating portion of the second electrode.

[0030] The winding end of the separator may further extend from the winding end of the coating portion of the first electrode by a first length in the winding direction.

[0031] The fixing member may be attached to the rolled end of the diaphragm in the axial direction from a point spaced apart from the axial end of the diaphragm by a second length.

[0032] The fixing member may be an adhesive tape having an adhesive layer on one surface.

[0033] An axial end of the coating portion of the first electrode may be spaced inwardly from an axial end of the separator by a third length.

[0034] When the winding end corner of the separator is maximally folded with the axial end of the fixing member as a folding bias point so that the outer surface of the winding end corner faces the outer circumference, the winding end corner of the coating portion of the first electrode is not exposed to the outside.

[0035] A folding line generated when the winding end corner of the separator is folded does not overlap with the winding end corner of the coating portion of the first electrode.

[0036] When the angle of the wound end of the diaphragm is folded outward to the maximum extent using any point of the wound end of the diaphragm as a folding bias point, the surface portion corresponding to the portion exposed to the outside can be approximated as a right triangle, and the minimum value of the angle formed by one side of the right triangle along the winding direction and the folding line can be defined as the minimum folding angle (θ min ).

[0037] The fixing member may be attached to the wound end of the diaphragm such that a second length corresponding to a distance between an axial end of the fixing member and an axial end of the diaphragm satisfies the following formula.

[0038] Second length < third length + first length * tan(θ min )

[0039] The minimum folding angle (θmin) may decrease as the diameter of the electrode assembly increases.

[0040] Minimum folding angle (θ min ) can decrease exponentially with the increase of the diameter of the electrode assembly.

[0041] A length of one side of the right triangle in the winding direction may be longer than a length of another side of the right triangle in the axial direction.

[0042] The diameter of the electrode assembly can be 13 mm to 103 mm, and the minimum folding angle (θ min ) can be 5 degrees to 60 degrees.

[0043] The first length may be 1 mm to 120 mm.

[0044] The third length may be 0.1 mm to 3.0 mm.

[0045] The separator may include an inner separator interposed between the first electrode and the second electrode, and an outer separator disposed outside the first electrode and winding a stack of the first electrode, the inner separator, and the second electrode.

[0046] The outer septum may be longer than the inner septum.

[0047] The separator extending from the winding end of the coating portion of the first electrode in the winding direction by a first length may be an external separator.

[0048] The uncoated portion of the first electrode may include a plurality of segments divided by cut grooves formed along the winding direction. The plurality of segments of the first electrode may protrude outward from an axial end of the separator in a direction away from an axial end of the coated portion of the first electrode. The plurality of segments of the first electrode may be bent toward the core to form a first bent surface region.

[0049] Alternatively, the uncoated portion of the first electrode may not be divided into a plurality of segments. The first bent surface region may be formed by bending the uncoated portion of the first electrode that does not include a segment structure.

[0050] The uncoated portion of the second electrode may include a plurality of segments divided by cut grooves formed along the winding direction. The plurality of segments of the second electrode may protrude outward from an axial end of the separator adjacent to the axial end of the coated portion of the first electrode. The plurality of segments of the second electrode may be bent toward the core to form a second bent surface region.

[0051] Alternatively, the uncoated portion of the second electrode may not be divided into a plurality of segments. The second bent surface region may be formed by bending the uncoated portion of the second electrode that does not include a segment structure.

[0052] In another aspect of the present disclosure, a cylindrical battery may be provided, comprising: an electrode assembly having at least one of the above-described features; a battery housing having an open end and a closed end and configured to accommodate the electrode assembly through the open end, the battery housing being electrically connected to a first electrode of the electrode assembly; a seal configured to seal the open end of the battery housing; and a terminal electrically connected to a second electrode of the electrode assembly and having a surface exposed to the outside of the battery housing.

[0053] The cylindrical battery may further include a first current collecting plate configured to electrically connect the uncoated portion of the first electrode and the battery case.

[0054] The first current collecting plate may be coupled to the side wall of the battery case. The first current collecting plate and the side wall of the battery case may be coupled by welding.

[0055] The sealing body may include a cover plate configured to cover the open end of the battery case, and a gasket interposed between an edge of the cover plate and the open end.

[0056] An edge of the first current collecting plate may be interposed between the gasket and a sidewall of the battery case.

[0057] The battery case may include a beaded portion formed by pressing an outer circumference near the open end inward, and an edge of the first current collecting plate may be in contact with the beaded portion.

[0058] The terminal may be mounted in a through-hole formed in the closed end of the battery case to be insulated from the battery case.

[0059] The terminal may include a terminal exposure portion exposed through an outer surface of the closed end, and a terminal insertion portion extending from the terminal exposure portion and inserted into the battery case through the penetration hole.

[0060] A lower edge of the terminal insertion portion may be riveted toward an inner surface of the closed end.

[0061] The cylindrical battery may further include a second current collecting plate configured to electrically connect the uncoated portion of the second electrode and a lower end of the terminal insertion portion.

[0062] The sealing body may include a cover plate that seals the open end of the battery case, and the terminal may be the cover plate.

[0063] The sealing body may include a cover plate covering the open end of the battery case, an edge of the cover plate may be coupled to the open end, and at least a portion of the first current collecting plate may be coupled to the cover plate.

[0064] The seal may include a cover plate configured to cover the open end of the battery housing. An edge of the cover plate may be coupled to the open end. At least a portion of an inner side of the edge of the cover plate may be electrically connected to the electrode assembly.

[0065] Preferably, at least a portion of the inner region of the edge of the cover plate may be welded to the first bent surface region of the first electrode.

[0066] In yet another aspect of the present disclosure, a battery pack is provided, comprising the plurality of cylindrical batteries described above.

[0067] In yet another aspect of the present disclosure, a vehicle including the battery pack is also provided.

[0068] Beneficial effects

[0069] According to the present disclosure, the attachment position of the fixing member is optimized by utilizing the distance between the winding end of the diaphragm and the winding end of the outermost coating portion along the winding direction, the distance between the end of the diaphragm and the end of the outermost coating portion along the axial direction of the electrode assembly, and the minimum folding angle of the winding end angle of the diaphragm. Even when the winding end angle of the diaphragm is folded outward to the maximum extent using the end of the fixing member as a folding bias point, the outermost coating portion can be fundamentally prevented from being exposed.

[0070] According to another aspect of the present disclosure, by optimizing the design of the attachment position of the fixing member, the distance between the winding end of the diaphragm and the winding end of the outermost coating portion along the winding direction can be reduced compared with the prior art, thereby reducing the amount of diaphragm used in the winding process of the electrode assembly.

[0071] According to yet another aspect of the present disclosure, a cylindrical battery having improved safety, a battery pack, and a vehicle including the same may be provided by fundamentally preventing exposure of an outermost coating portion that may occur while operating an electrode assembly during assembly of the cylindrical battery.

[0072] Furthermore, the present disclosure may have several other effects, and these effects will be described in each embodiment, or any description of effects that can be easily inferred by those skilled in the art will be omitted. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, are used to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure is not to be construed as being limited to the accompanying drawings.

[0074] Figure 1 is a plan view showing an electrode structure for manufacturing a conventional tabless cylindrical battery.

[0075] Figure 2 1 is a diagram showing the electrode winding process of a conventional jointless cylindrical battery.

[0076] Figure 3 is a diagram illustrating a process of welding a current collector to a bent surface area of ​​an uncoated portion in a conventional tabless cylindrical battery.

[0077] Figure 4 is a graph showing the winding end angle (S) of the separator S when it is wound on the outer periphery of the electrode assembly A according to the prior art. c ) is folded outward, exposing the coating portion of the outermost electrode E (E coating )'s state.

[0078] Figure 5 is a plan view illustrating a laminated state of electrodes and separators before an electrode assembly is wound according to an embodiment of the present disclosure.

[0079] Figure 6 is a cross-sectional view illustrating a laminated state of electrodes and separators before an electrode assembly is wound according to an embodiment of the present disclosure.

[0080] Figure 7 is a cross-sectional view showing an electrode assembly according to an embodiment of the present disclosure, taken perpendicularly to an axial direction.

[0081] Figure 8 is a conceptual diagram for explaining an optimal design of an attachment position of a fixing member according to an embodiment of the present disclosure.

[0082] Figure 9 is the diameter (d) of the electrode assembly and the minimum folding angle (θ) obtained by function fitting according to an embodiment of the present disclosure.min ) is a graph of an exponential function that shows the relationship between

[0083] Figure 10 is a plan view illustrating relative positions of a coating portion of a first electrode, a separator, and a fixing member when the fixing member is attached to a designed position according to an embodiment of the present disclosure.

[0084] Figure 11 is a partial perspective view of an electrode assembly, showing that when a fixing member is attached to a designed position according to an embodiment of the present disclosure, segments of the second electrode are prevented from contacting a coating portion of the first electrode even when folded outward.

[0085] Figure 12 is a cross-sectional view showing a cylindrical battery according to an embodiment of the present disclosure, taken along a winding axis direction Y.

[0086] Figure 13 is a cross-sectional view showing a cylindrical battery according to another embodiment of the present disclosure, taken along a winding axis direction Y.

[0087] Figure 14 is a diagram schematically illustrating a battery pack according to an embodiment of the present disclosure.

[0088] Figure 15 is a diagram schematically showing a vehicle including a battery pack according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0089] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be interpreted as limited to the general meaning and dictionary meaning, but should be interpreted based on the meaning and concept corresponding to the technical aspects of the present disclosure on the basis of the principle that the inventor is allowed to appropriately define the terms for the best description.

[0090] Therefore, the descriptions presented herein are merely preferred examples for illustrative purposes, and are not intended to limit the scope of the present disclosure, and it should be understood that other equivalents and modifications may be made thereto without departing from the scope of the present disclosure.

[0091] In addition, to help understand the present disclosure, the drawings are not drawn to scale and the sizes of some components may be exaggerated. In addition, the same reference numerals may be assigned to the same components in different embodiments.

[0092] Stipulating that two compared objects are "the same" means that they are "substantially the same." Thus, the term "substantially the same" can include deviations that are considered low in the art (e.g., less than 10% deviation). Additionally, uniformity of a parameter in a region can mean that the parameter is uniform from an average viewing angle in the corresponding region.

[0093] Although the terms "first", "second", etc. are used to describe different elements, these elements are not limited by these terms. These terms are used to distinguish one element from another element, and unless otherwise specified, the first element may be the second element.

[0094] Throughout the specification, unless otherwise specified, each element may be in the singular or in the plural.

[0095] When an element is “on (or under)” or “over (or under)” another element, the element may be located on the upper surface (or lower surface) of the other element, and intervening elements may be present between the element and the other element located above (or below) the element.

[0096] Additionally, when an element is referred to as being “connected,” “coupled,” or “linked” to another element, the element may be directly connected or coupled to the other element, but it should be understood that intermediate elements may exist between the elements, or the elements may be “connected,” “coupled,” or “linked” to each other through another element.

[0097] Throughout the specification, unless expressly stated otherwise, “A and / or B” means A or B, or both A and B, and “C to D” means C above and D below unless expressly stated otherwise.

[0098] For ease of description, the direction along the length of the winding axis of the electrode assembly wound into a roll is referred to herein as the axial direction Y. Furthermore, the direction around the winding axis is referred to herein as the circumferential direction X or the peripheral direction X. Furthermore, the direction approaching or away from the winding axis is referred to as the radial direction. Specifically, the direction approaching the winding axis is referred to as the centripetal direction, and the direction away from the winding axis is referred to as the centrifugal direction.

[0099] First, an electrode assembly according to an embodiment of the present disclosure is described.

[0100] Figure 5 and Figure 6 1 and 2 are respectively a plan view and a cross-sectional view illustrating a laminated state of electrodes and separators before an electrode assembly according to an embodiment of the present disclosure is wound. Figure 7 is a cross-sectional view showing an electrode assembly according to an embodiment of the present disclosure, taken perpendicularly to an axial direction.

[0101] Reference Figures 5 to 7 The electrode assembly JR according to an embodiment of the present disclosure may have a structure in which the first electrode 40 and the second electrode 50 having a sheet shape and the separator 60 interposed therebetween are wound in one direction. The first electrode 40 and the second electrode 50 may be a negative electrode and a positive electrode, respectively, or vice versa.

[0102] The separator 60 may include an inner separator 60a interposed between the first electrode 40 and the second electrode 50, and an outer separator 60b arranged outside the first electrode 40 and wound around the stack of the first electrode 40, the inner separator 60a, and the second electrode 50. The outer separator 60b is longer than the inner separator 60a. Therefore, both ends of the outer separator 60b in the winding direction X extend further outward than both ends of the inner separator 60a in the winding direction X.

[0103] The first electrode 40 and the second electrode 50 may have a pair of short sides and a pair of long sides. The pair of long sides extend between the pair of short sides. The pair of short sides extend along the axial direction Y of the electrode assembly JR. The pair of long sides extend along the winding direction X of the electrode assembly JR.

[0104] The first electrode 40 includes a coated portion 40a and an uncoated portion 40b along the longitudinal direction. Similarly, the second electrode 50 includes a coated portion 50a and an uncoated portion 50b along the longitudinal direction. The coated portions 40a and 50a may be active material coatings. The uncoated portions 40b and 50b may be current collectors coated with active material. The current collector may be a metal foil. The coated portions 40a and 50a may be provided on both surfaces of the current collector. The uncoated portion 40b of the first electrode 40 extends along the longitudinal end of the first electrode 40 in the winding direction X. The uncoated portion 50b of the second electrode 50 extends along the longitudinal end of the second electrode 50 in the winding direction X.

[0105] Optionally, the boundary between the coated portion 40a and the uncoated portion 40b of the first electrode 40 may be covered by an insulating coating (not shown). Similarly, the boundary between the coated portion 50a and the uncoated portion 50b of the second electrode 50 may be covered by an insulating coating. The insulating coating may include a resin and an inorganic filler.

[0106] The uncoated portion 40b of the first electrode 40 may include a plurality of segments 40c divided by a cutting groove 40d formed along the winding direction X. The cutting groove 40d may be formed by a laser grooving process. The first electrode 40 may not include a segment 40c located in an area adjacent to the core and the periphery of the electrode assembly JR. The plurality of segments 40c of the first electrode 40 may protrude outward from the end 60d in the axial direction Y of the separator 60 in a direction away from the end 40a1 in the axial direction Y of the coated portion 40a of the first electrode 40. The plurality of segments 40c of the first electrode 40 may be bent toward the core of the electrode assembly JR to form a first bent surface area.

[0107] The uncoated portion 50b of the second electrode 50 may include a plurality of segments 50c divided by a cutting groove 50d formed along the winding direction X. The cutting groove 50d may be formed by a laser grooving process. The second electrode 50 may not include a segment 50c located in an area adjacent to the core and the periphery of the electrode assembly JR. The plurality of segments 50c of the second electrode 50 may protrude outward from an end 60c in the axial direction Y of the separator 60 adjacent to the end 40a1 in the axial direction Y of the coated portion 40a of the first electrode 40. The plurality of segments 50c of the second electrode 50 may be bent toward the core of the electrode assembly JR to form a second bent surface area.

[0108] The width of the segments 40c, 50c corresponds approximately to the width of the lower end. The width of the segments 40c, 50c may be 1 mm to 11 mm. The width of the segment 61 may be constant, or may increase gradually or progressively from the core to the periphery.

[0109] The height of the segments 40c, 50c corresponds approximately to the shortest distance between the upper and lower ends. The height of the segments 40c, 50c may be 2 mm to 10 mm. The height of the segments 40c, 50c may be constant, or may increase gradually or gradually from the core to the periphery.

[0110] The spacing P between the segments 40c and 50c corresponds to the distance between the two points where a straight line passing through the lower end of the cut groove in the winding direction X intersects two straight lines extending from the sides of the segments 40c and 50c on either side of the cut groove. The spacing P between the segments 40c and 50c can be 0.05 mm to 1 mm. The spacing P between the segments 40c and 50c can be constant or can increase gradually or gradually from the core to the periphery.

[0111] The shapes of the segments 40c, 50c may be geometric shapes known in the art (eg, rectangle, parallelogram, trapezoid, semicircle, semi-ellipse, etc.).

[0112] In the present disclosure, the uncoated portion 40b of the first electrode 40 may not be divided into the plurality of segments 40c by the cutting groove 40d. Similarly, the uncoated portion 50b of the second electrode 50 may not be divided into the plurality of segments 50c by the cutting groove 50d.

[0113] The outermost coating portion of the electrode assembly JR may be the coating portion 40a of the first electrode 40. The winding end 60e of the separator 60 may extend from the winding end 40e of the coating portion 40a of the first electrode 40 in the winding direction X by a first length (d1).

[0114] The first length (d1) may be appropriately set so that the coating portion 40a of the first electrode 40 is not exposed to the outside in the winding direction X. If the first length (d1) is too small, the coating portion 40a may be exposed in the winding direction X due to a length tolerance of the electrode and the separator when the electrode assembly JR is wound. If the first length (d1) is too large, unnecessary waste of the separator 60 may result.

[0115] The first length (d1) can be more than 1 mm, more than 5 mm, more than 10 mm, more than 15 mm, more than 20 mm, or more than 25 mm. The first length (d1) can be less than 120 mm, less than 110 mm, less than 100 mm, less than 90 mm, less than 80 mm, less than 70 mm, less than 60 mm, less than 50 mm, or less than 40 mm. The upper limit and lower limit of the first length (d1) can be selected from the above lower limit condition and the above upper limit condition. Preferably, the first length (d1) can be more than 1 mm and less than 40 mm.

[0116] The fixing member 70 may be attached to the coiled end 60 e of the diaphragm 60 in the axial direction Y from a point spaced apart from the axial end 60 c of the diaphragm 60 by a second length ( d2 ).

[0117] An important feature of the present disclosure is that the attachment position of the fixing member 70 (ie, the second length (d2)) is optimally designed so that when the winding end angle (S c ) is folded outward, the winding end corners of the coating portion 40a of the first electrode 40 are not exposed.

[0118] An end portion 40 a 1 of the coating portion 40 a of the first electrode 40 in the axial direction Y may be spaced inwardly from the axial end 60 c of the diaphragm 60 by a third length ( d3 ).

[0119] When winding the electrode assembly JR, the third length (d3) may be appropriately set in consideration of the tolerance of the maze of the separator 60. If the third length (d3) is too small, the coating portion 40a of the first electrode 40 may be exposed to the outside of the separator 60. If the third length (d3) is too large, the ratio of the height of the coating portion 40a to the total height of the electrode assembly JR decreases, thereby reducing the energy density.

[0120] The third length (d3) can be greater than 0.1 mm, greater than 0.5 mm, or greater than 1 mm. The third length (d3) can be less than 3 mm, less than 2.5 mm, less than 2.0 mm, or less than 1.5 mm. The upper limit and lower limit of the third length (d3) can be selected from the above lower limit conditions and upper limit conditions. Preferably, the third length (d3) can be greater than 0.1 mm and less than 3 mm.

[0121] Figure 81 is a conceptual diagram for explaining an optimal design of an attachment position of the fixing member 70 according to an embodiment of the present disclosure.

[0122] Figure 8 1 is an enlarged view showing the relative positions of the separator 60 and the first electrode 40 at a portion where the winding of the electrode assembly JR ends. The relative positions are shown based on the expanded state of the electrode assembly JR.

[0123] Reference Figure 8 , the fixing member 70 may be connected to the winding end 60 e of the separator 60 to prevent the winding state of the electrode assembly JR from being released.

[0124] The fixing member 70 may be a tape having an adhesive layer formed on one side.

[0125] When processing the electrode assembly JR, the winding end angle (S c ) can be folded outwards. If the winding end angle (S c ) folded, the winding end angle (S c ) may be in contact with the outer periphery of the electrode assembly JR.

[0126] The winding end angle in the folded state (S c ) forms a right triangle △OL with the folding line L as the hypotenuse a L b The first end of the folding line L (L a ) is located at the rolled end 60e of the diaphragm 60, and the second end (L b ) is located at the end portion along the axial direction Y of the diaphragm 60.

[0127] The first end of the folding line L (L a ) and the second end (L b ) can be positioned according to the winding end angle (S c ) is changed by the folding direction and folding strength. According to the position of the fixing member 70 and the diameter of the electrode assembly JR, the first end (L a ) and the second end (L b ) can be located to a specific range.

[0128] The first end (L a ) can be moved along the winding end 60e of the diaphragm 60 only to the end 70e in the axial direction Y of the fixing member 70. When the first end (L a ) is fixed, the second end (L b ) can be calculated based on the winding end angle (S c ) is moved in the opposite direction of the winding direction X. The moving distance may be limited by the curvature of the outer periphery of the electrode assembly JR (ie, the diameter of the electrode assembly JR).c )When folded, the first end (L a ) becomes the folding bias point. When the winding end angle (S c ) folded, the folding bias point becomes the point used to make the winding end angle (S c ) is the reference point for outward rotation.

[0129] Corresponding to the winding end angle in the folded state (S c ) of the right triangle △OL a L b Relative to the folding line L and the right triangle △O'L a L b Symmetrical. Right triangle △O'L a L b is a geometric figure that corresponds approximately to the winding end angle (S) of the diaphragm 60. c ) The surface part that is exposed to the outside when folded.

[0130] The winding end angle (S c ) is defined as the folding angle (θ) between the folding line L and the right triangle △O'L a L b One side of the side along the winding direction X (O'L b ) forms an angle (θ).

[0131] When the first end (L a ) is fixed and serves as the folding bias point, the second end of the folding line L (L b ) can be limited by the diameter of the electrode assembly JR. a ) is fixed, when the winding end angle (S c ) is folded outward to the maximum extent, the second end (L b ) can be moved to the folding angle (θ) to reduce to the minimum folding angle (θ min ) location.

[0132] Since the first end of the folding line L (L a ) acts as a folding bias point through the fixing member 70, so the right triangle (△O'L a L b ) of an edge (O'L b ) along the winding direction X is longer than the other side of the right triangle (O'L a ) is longer in the axial direction Y.

[0133] According to experiments, as the diameter of the electrode assembly JR increases, the moving distance (L b ) increases and the minimum folding angle (θ min) tends to decrease. That is, as the diameter of the electrode assembly JR increases, the minimum folding angle (θ min ) can be reduced linearly or nonlinearly.

[0134] When the diameter of the electrode assembly JR is 18 mm to 50 mm, the minimum folding angle (θ min ) can be 5 degrees or more, 10 degrees or more, 15 degrees or more, 20 degrees or more, or 25 degrees or more. The minimum folding angle (θ min ) can be less than 60 degrees, less than 55 degrees, less than 50 degrees, less than 45 degrees, less than 40 degrees or less than 35 degrees. The minimum folding angle (θ min The upper limit and lower limit of the range of ) can be selected from the above upper limit condition and the above lower limit condition. Preferably, the minimum folding angle (θ min ) can be from 20 degrees to 40 degrees.

[0135] Figure 8 When the first end of the folding line L (L a ) is fixed in three different positions, and the winding end angle (S) of the diaphragm 60 is folded outward to the maximum extent. c ) when one side of the right triangle (O'L b ) forms the minimum folding angle (θ min ) is located at the folding line L.

[0136] The winding end angle (S) of the separator 60 of the folded electrode assembly JR can be determined by repeatedly performing experiments. c ) to determine the minimum folding angle (θ min The minimum folding angle (θ ) can be uniquely determined according to the specifications of the electrode assembly JR. min ). Minimum folding angle (θ min ) is mainly affected by the diameter of the electrode assembly JR. The minimum folding angle (θ min ) can also be affected by the material and thickness of the diaphragm 60. The minimum folding angle (θ min ) is determined as the winding end angle (S) of the diaphragm 60 when each point is used as a folding bias point. c ) The minimum value of the folding angle (θ) when the folding is intentionally maximized at a plurality of points of the rolled end 60e of the diaphragm 60. The plurality of points of the rolled end 60e of the diaphragm 60 may be selected from points to which the fixing member 70 is not attached.

[0137] In one example, when at the first end (L a ) The winding end angle (S) of the diaphragm 60 is folded outward as much as possible in a state where the diaphragm 60 is fixed to the first point from the upper side. c ), the folding line L does not overlap with the coating portion 40a of the first electrode 40. The first end (L a) is fixed to the first point corresponds to a preferred embodiment of the present disclosure. Therefore, the fixing member 70 can be attached to the winding end 60e of the diaphragm 60 so that the end 70e of the fixing member 70 in the axial direction Y is located at the first point. Then, even if the winding end angle (S) of the diaphragm 60 is folded to the maximum extent using the axial end 70e of the fixing member 70 as the folding bias point, c ) so that its outer surface contacts the outer periphery of the electrode assembly JR, and the coating portion 40a of the first electrode 40 is not exposed to the outside.

[0138] In another example, when at the first end (L a ) The winding end angle (S) of the diaphragm 60 is folded outward as much as possible in a state where it is fixed to the second point from the upper side. c ), the folding line L just passes through the corner of the coating portion 40a of the first electrode 40. For the preferred embodiment of the present disclosure, the first end (L a ) is fixed to the second point corresponds to the boundary condition. Therefore, if the fixing member 70 is attached to the winding end 60e of the diaphragm 60 so that the end 70e of the fixing member 70 in the axial direction Y is located at the second point, then when the winding end angle (S) of the diaphragm 60 is maximally folded using the axial end 70e of the fixing member 70 as the folding bias point, c ) so that its outer surface contacts the outer periphery of the electrode assembly JR, the corner of the coating portion 40a of the first electrode 40 is located on the folding line L.

[0139] In yet another example, when at the first end (L a ) is fixed at the third point from the upper side, and the winding end angle (S) of the separator 60 is folded outward as much as possible. c ), the folding line L passes through the coating portion 40a of the first electrode 40. The first end (L a ) is fixed at the third point corresponds to an undesirable comparative example. Therefore, if the fixing member 70 is attached to the winding end 60e of the diaphragm 60 so that the end 70e of the fixing member 70 in the axial direction Y is located at the third point, then when the winding end angle (S) of the diaphragm 60 is folded to the maximum using the axial end 70e of the fixing member 70 as the folding bias point, the winding end angle (S) of the diaphragm 60 is folded to the maximum. c ) so that its outer surface contacts the periphery of the electrode assembly JR, the coating portion 40a of the first electrode 40 is exposed to the outside. As explained in the background section, the exposure of the coating portion 40a increases the risk of low voltage and causes an internal short circuit.

[0140] From a general perspective, when any point of the rolled end 60e of the diaphragm 60 is used as a folding bias point to fold the rolled end angle (S) outward to the maximum extent, c), if the surface portion corresponding to the exposed portion is approximately a right triangle (△O'L a L b ) and one side of the right triangle (O'L b The minimum value of the angle formed by the winding direction X and the folding line L is defined as the minimum folding angle (θ min ), preferably, the fixing member 70 is attached to the winding end 60e of the diaphragm so that the second length (d2) corresponding to the distance between the end in the axial direction Y of the fixing member 70 and the axial end 60c of the diaphragm 60 satisfies the following formula.

[0141] formula:

[0142] Second length (d2) < third length (d3) + first length (d1) * tan(θ min )

[0143] In the above formula, the first length (d1), the third length (d3) and the minimum folding angle (θ min ) is a value predetermined by the design conditions of the electrode assembly JR.

[0144] Hereinafter, an embodiment of calculating the desired attachment position of the fixing member 70 while adjusting the diameter of the electrode assembly JR in various ways will be described in detail. The separator 60 uses a composite separator in which a porous inorganic coating is formed on both surfaces of a substrate made of a polyethylene film widely used in the battery technology field. The substrate has a thickness of 10 μm, and the inorganic coating has a thickness of 3 μm. The porous inorganic coating contains aluminum oxide particles.

[0145] First embodiment:

[0146] When the diameter of the electrode assembly JR is 13 mm, the first length (d1) is 22 mm, and the third length (d3) is 1 mm, the minimum folding angle (θ min ) is 36.0 degrees. By setting the minimum folding angle (θ min ), the first length (d1) and the third length (d3) are substituted into the right side of the formula to obtain 16.984 mm as the upper boundary value of the second length (d2).

[0147] Therefore, for the electrode assembly JR of the first embodiment, in order to maximize the winding end angle (S) of the separator 60 even when the separator 60 is folded outward. c ) also prevents the coating portion of the electrode from being exposed, and considering the attachment tolerance of the fixing member 70, preferably, the fixing member 70 is attached to the winding end 60e of the diaphragm 60 so that the end portion of the fixing member 70 in the axial direction Y and the end portion 60c of the diaphragm 60 in the axial direction Y will not be separated by more than 16.9 mm.

[0148] Second embodiment:

[0149] When the diameter of the electrode assembly JR is 36 mm, the first length (d1) is 22 mm, and the third length (d3) is 1 mm, the minimum folding angle (θ min ) is 27.1 degrees. By setting the minimum folding angle (θ min ), the first length (d1) and the third length (d3) are substituted into the right side of the formula, and 12.258 mm can be obtained as the upper boundary value of the second length (d2).

[0150] Therefore, for the electrode assembly JR of the second embodiment, in order to prevent the coating portion of the electrode from being exposed even when the winding end angle (Sc) of the diaphragm 60 is folded outward to the maximum extent, considering the attachment tolerance of the fixing member 70, preferably, the fixing member 70 is attached to the winding end 60e of the diaphragm 60 so that the end portion of the fixing member 70 in the axial direction Y is not separated from the end portion 60c in the axial direction Y of the diaphragm 60 by more than 12.2 mm.

[0151] Third embodiment:

[0152] When the diameter of the electrode assembly JR is 50 mm, the first length (d1) is 22 mm, and the third length (d3) is 1 mm, the minimum folding angle (θ min ) is 23.4 degrees. By setting the minimum folding angle (θ min ), the first length (d1) and the third length (d3) are substituted into the right side of the formula, and 10.520 mm can be obtained as the upper limit value of the second length (d2).

[0153] Therefore, for the electrode assembly JR of the third embodiment, in order to maximize the winding end angle (S) of the separator 60 even when the separator 60 is folded outward. c ) also prevents the coating portion of the electrode from being exposed, and considering the attachment tolerance of the fixing member 70, preferably, the fixing member 70 is attached to the winding end 60e of the diaphragm 60 so that the end portion of the fixing member 70 in the axial direction Y and the end portion 60c of the diaphragm 60 in the axial direction Y are not separated by more than 10.5 mm.

[0154] Fourth embodiment:

[0155] When the diameter of the electrode assembly JR is 103 mm, the first length (d1) is 22 mm, and the third length (d3) is 1 mm, the minimum folding angle (θ min ) is 18.6 degrees. By setting the minimum folding angle (θ min ), the first length (d1) and the third length (d3) are substituted into the right side of the formula, and 8.404 mm can be derived as the upper boundary value of the second length (d2).

[0156] Therefore, for the electrode assembly JR of the fourth embodiment, in order to maximize the winding end angle (S) of the separator 60 even when the separator 60 is folded outward. c ) also prevents the coating portion of the electrode from being exposed, and considering the attachment tolerance of the fixing member 70, preferably, the fixing member 70 is attached to the winding end 60e of the diaphragm 60 so that the end portion of the fixing member 70 in the axial direction Y and the end portion 60c of the diaphragm 60 in the axial direction Y will not be separated by more than 8.4 mm.

[0157] The first to fourth embodiments described above support the minimum folding angle (θ min ) decreases as the diameter of the electrode assembly JR increases.

[0158] When the diameter of the electrode assembly JR is d, d and the minimum folding angle (θ min ) can be roughly expressed by the following exponential function.

[0159] θ min =θ min,0 +A*e (R0)*d

[0160] (Here, θ min,0 is 17.14399, A is 27.49876, and R0 is -0.02886.)

[0161] The electrode assembly JR according to the first to fourth embodiments can be formed by using the diameter (d) and the minimum folding angle (θ min ) is fitted to the data to determine the constant θ of the exponential function min,0 , A and R0: (13mm, 36 degrees), (36mm, 27.1 degrees), (50mm, 23.4 degrees) and (103mm, 18.6 degrees).

[0162] Figure 9 is a graph of an exponential function obtained by function fitting according to an embodiment of the present disclosure. Figure 9 In the embodiment, the diameter (d) and the minimum folding angle (θ) of the electrode assembly JR according to the first to fourth embodiments are min ) is represented by a dot. Figure 9 , it can be found that the exponential function roughly represents the minimum folding angle (θ min ) according to the unique variation pattern of the diameter (d) of the electrode assembly JR.

[0163] It is obvious to those skilled in the art that the constant θ of the exponential function min , 0, A and R0 can vary according to the first length (d1) and the third length (d3).

[0164] The exponential function may be used to estimate the minimum folding angle (θ) of the electrode assembly JR having a diameter different from that of the electrode assemblies of the first to fourth embodiments. min ).

[0165] As an example, when the diameter of the electrode assembly JR is 17 mm, the first length (d1) is 22 mm, and the third length (d3) is 1 mm, the winding end angle (S) of the separator 60 may be calculated using an exponential function. c ) of the minimum folding angle (θ min ) is approximately determined to be 33.980 degrees. In addition, by min ) into the right side of the formula, the upper boundary value of the second length (d2) can be determined as 15.828 mm.

[0166] Therefore, for the electrode assembly JR having a diameter of 17 mm, in order to maximize the winding end angle (S) of the separator 60 even when the separator 60 is folded outward, c ) also prevents the coating portion of the electrode from being exposed, and considering the attachment tolerance of the fixing member 70, preferably, the fixing member 70 is attached to the winding end 60e of the diaphragm 60 so that the end portion of the fixing member 70 in the axial direction Y and the end portion 60c of the diaphragm 60 in the axial direction Y will not be separated by more than 15.8 mm.

[0167] As another example, when the diameter of the electrode assembly JR is 20 mm, the first length (d1) is 22 mm, and the third length (d3) is 1 mm, the winding end angle (S) of the separator 60 may be calculated using an exponential function. c ) of the minimum folding angle (θ min ) is approximately determined to be 32.584 degrees. In addition, by min ) into the right side of the formula, the upper boundary value of the second length (d2) can be determined as 15.061 mm.

[0168] Therefore, for the electrode assembly JR with a diameter of 20 mm, in order to prevent the coating portion of the electrode from being exposed even when the winding end angle (Sc) of the diaphragm 60 is folded outward to the maximum extent, considering the attachment tolerance of the fixing member 70, preferably, the fixing member 70 is attached to the winding end 60e of the diaphragm 60 so that the end portion of the fixing member 70 in the axial direction Y is not separated from the end portion 60c in the axial direction Y of the diaphragm 60 by more than 15.0 mm.

[0169] As another example, when the diameter of the electrode assembly JR is 45 mm, the first length (d1) is 22 mm, and the third length (d3) is 1 mm, the winding end angle (S) of the separator 60 may be calculated using an exponential function. c) of the minimum folding angle (θ min ) is approximately determined to be 24.648 degrees. In addition, by min ) into the right side of the formula, the upper boundary value of the second length (d2) can be determined as 11.095 mm.

[0170] Therefore, for the electrode assembly JR having a diameter of 45 mm, in order to maximize the winding end angle (S) of the separator 60 even when folded outward. c ) also prevents the coating portion of the electrode from being exposed, and considering the attachment tolerance of the fixing member 70, preferably, the fixing member 70 is attached to the winding end 60e of the diaphragm 60 so that the end portion of the fixing member 70 in the axial direction Y and the end portion 60c of the diaphragm 60 in the axial direction Y are not separated by more than 11.0 mm.

[0171] Figure 10 is a plan view illustrating relative positions of the coating portion 40 a of the first electrode 40 , the separator 60 , and the fixing member 70 when the fixing member 70 is attached so that the second length ( d2 ) satisfies the above formula according to an embodiment of the present disclosure.

[0172] Figure 11 is a partial perspective view of an electrode assembly JR according to an embodiment of the present disclosure, which shows that when the fixing member 70 is attached so that the second length (d2) satisfies the above formula, the segment 50c of the second electrode 50 is prevented from contacting the coating portion 40a of the first electrode 40 even when folded outward.

[0173] Reference Figure 10 and Figure 11 When the attachment position of the fixing member 70 according to the embodiment of the present disclosure is designed, during the process of manufacturing the electrode assembly JR and the process of processing the electrode assembly JR to assemble a cylindrical battery, even if the winding end angle (S) of the separator 60 is folded to the maximum extent with the end 70e in the axial direction Y of the fixing member 70 as the folding bias point, the winding end angle (S) of the separator 60 is folded to the maximum extent. c ), it is also possible to prevent the coating portion 40a of the first electrode 40 located on the outermost side from being exposed to the outside. Therefore, even if the winding end angle (S c ) is folded outward and contacts the outer periphery of the electrode assembly JR, thereby fundamentally preventing the coated portion 40a of the first electrode 40 from contacting the folded segment 50c of the second electrode 50. Furthermore, active material particles can be prevented from falling off from the coated portion 40a of the first electrode 40. This prevents short circuits from occurring inside the cylindrical battery and reduces the risk of low voltage.

[0174] Meanwhile, the above-described embodiment can be substantially equally applied not only to the upper portion of the electrode assembly JR but also to the lower portion of the electrode assembly JR, wherein the plurality of segments 40 c included in the uncoated portion 40 a of the first electrode 40 are exposed to the outside of the separator 60 .

[0175] Furthermore, when the coating portion 50a of the second electrode 50 is arranged closer to the periphery of the electrode assembly JR than the coating portion 40a of the first electrode 40, the above embodiment may be substantially equally applied to the end portion of the coating portion 50a of the second electrode 50 in the axial direction Y.

[0176] In addition, when the above embodiment is applied to the upper or lower portion of the electrode assembly JR in which multiple segments are exposed to the outside of the diaphragm 60, if the insulating coating is formed at the boundary between the coated portion and the uncoated portion, the third length (d3) can be a length measured based on the end portion of the coating portion exposed to the outside (i.e., the boundary line between the coating portion and the insulating coating).

[0177] The above embodiment can also be applied to the case where the uncoated portions of the first electrode and the second electrode are not divided into segments. In this application example, even if the winding end angle (S) of the separator 60 is maximized by taking the end 70e in the axial direction Y of the fixing member 70 as the folding bias point, c ), it is also possible to prevent the coating portion of the electrode arranged at the outermost side of the electrode assembly JR from being exposed to the outside and coming into contact with a portion having an opposite polarity.

[0178] In the present disclosure, a positive electrode active material coated on a positive electrode and a negative electrode active material coated on a negative electrode may be used without limitation as long as they are active materials known in the art.

[0179] In one example, the positive electrode active material may include a x M y ]O 2+z (A includes at least one element selected from Li, Na and K; M includes at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Mo, Sc, Zr, Ru and Cr; x ≥ 0, 1 ≤ x + y ≤ 2, 0.1 ≤ z ≤ 2; and the stoichiometric coefficients x, y, z and M are selected so that the compound remains electrically neutral).

[0180] In another example, the positive electrode active material may be an alkali metal compound xLiM disclosed in US Pat. No. 6,677,082, US Pat. No. 6,680,143, etc. 1 O2-(1-x)Li2M 2 O3, (where M 1comprising at least one element with an average oxidation state of 3; M 2 comprising at least one element with an average oxidation state of 4; and 0 ≤ x ≤ 1).

[0181] In another example, the positive electrode active material may be represented by the general formula Li a M 1 x Fe 1-x M 2 y P 1-y M 3 z O 4-z (M 1 comprising at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Mg, and Al; M 2 comprising at least one element selected from Ti, Si, Mn, Co, Fe, Cr, Mo, Ni, Nd, Al, Mg, As, Sb, Si, Ge, V, and S; M 3 comprising a halogen element, optionally including F; 0 < a ≤ 2, 0 ≤ x ≤ 1, 0 ≤ y < 1, 0 ≤ z < 1; selecting the stoichiometric coefficients a, x, y, and z such that the compound remains electrically neutral) or a lithium metal phosphate represented by Li3M2(PO4)3 [M comprising at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Mg, and Al].

[0182] Preferably, the positive electrode active material may include primary particles and / or secondary particles in which the primary particles are aggregated.

[0183] In one example, the negative electrode active material may be a carbon material, a lithium metal or a lithium metal compound, silicon or a silicon compound, tin or a tin compound, etc. Metal oxides with a potential lower than 2V (e.g., TiO2 and SnO2) can also be used as the negative electrode active material. As the carbon material, low-crystalline carbon, high-crystalline carbon, etc. can be used.

[0184] The separator can be a porous polymer membrane, such as a porous polymer membrane made of a polyolefin-based polymer (e.g., ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, etc. or their laminates). As another example, the separator can be an ordinary porous non-woven fabric, such as a non-woven fabric made of high-melting-point glass fibers, polyethylene terephthalate fibers, etc.

[0185] At least one surface of the separator may include an inorganic particle coating. The separator itself can also be made of an inorganic particle coating. The particles constituting the coating can have a structure in which they are joined with an adhesive such that there is an interstitial volume between adjacent particles.

[0186] The electrode assembly JR according to an embodiment of the present disclosure may be applied to a jellyroll-type cylindrical battery.

[0187] The cylindrical battery may be, for example, a cylindrical battery having a shape factor ratio (defined as a value obtained by dividing the diameter of a cylindrical battery by its height, i.e., a ratio of diameter (Φ) to height H) greater than about 0.4. Here, the shape factor refers to a value representing the diameter and height of a cylindrical battery.

[0188] The cylindrical battery may have a diameter of 35 mm or more, preferably 40 mm to 50 mm. The cylindrical battery may have a height of 70 mm or more, preferably 75 mm to 90 mm. The cylindrical battery according to an embodiment of the present disclosure may be, for example, a 46110 battery, a 4875 battery, a 48110 battery, a 4880 battery, or a 4680 battery. In the numerical value representing the form factor, the first two digits represent the diameter of the battery, and the remaining digits represent the height of the battery.

[0189] When an electrode assembly with a jointless structure is applied to a cylindrical battery with a shape factor ratio greater than 0.4, when the uncoated portion is bent, the stress applied in the radial direction is large, so that the uncoated portion may be easily torn. In addition, when the current collecting plate is welded to the bent surface area of ​​the uncoated portion, it is necessary to sufficiently increase the number of stacked layers of the uncoated portion in the bent surface area to fully ensure the welding strength and reduce the resistance. This requirement can be achieved by the electrode and electrode assembly according to the embodiment (variation) of the present disclosure.

[0190] A battery according to one embodiment of the present disclosure may be a generally cylindrical battery having a diameter of approximately 46 mm, a height of approximately 110 mm, and an aspect ratio of 0.418.

[0191] A battery according to another embodiment may be a generally cylindrical battery having a diameter of approximately 48 mm, a height of approximately 75 mm, and an aspect ratio of 0.640.

[0192] A battery according to yet another embodiment may be a generally cylindrical battery having a diameter of approximately 48 mm, a height of approximately 110 mm, and an aspect ratio of 0.436.

[0193] A battery according to yet another embodiment may be a generally cylindrical battery having a diameter of approximately 48 mm, a height of approximately 80 mm, and an aspect ratio of 0.600.

[0194] A battery according to yet another embodiment may be a generally cylindrical battery having a diameter of approximately 46 mm, a height of approximately 80 mm, and an aspect ratio of 0.575.

[0195] It is obvious to those skilled in the art that the form factor ratio, diameter, and height of the cylindrical battery in the embodiment of the present disclosure are not limited to those described above.

[0196] Hereinafter, a cylindrical battery according to an embodiment of the present disclosure will be described in detail.

[0197] Figure 12 1 is a cross-sectional view showing a cylindrical battery 190 according to an embodiment of the present disclosure, taken along a winding axis direction Y. FIG.

[0198] Reference Figure 12 The cylindrical battery 190 according to an embodiment of the present disclosure includes an electrode assembly 110 having a first electrode 40, a separator 60, and a second electrode 50, 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.

[0199] The battery case 142 is a cylindrical container with an opening at the top. The battery case 142 is made of a conductive metal material. The battery case 142 accommodates the electrode assembly 110 in an internal space through the top opening.

[0200] The electrode assembly 110 may have a jellyroll shape. Figure 6 As shown, the electrode assembly 110 may be manufactured by sequentially stacking the outer separator 60b, the first electrode 40, the inner separator 60a, and the second electrode 50 at least once and winding the stacked body around one axis.

[0201] The first electrode 40 may be a cathode and the second electrode 50 may be a cathode, or vice versa.

[0202] The electrode assembly 110 may include first and second bending surface areas F1 and F2 at upper and lower portions. The first current collecting plate 144 may be welded to the first bending surface area F1 of the first non-coating portion 146a, and the second current collecting plate 145 may be welded to the second bending surface area F2 of the second non-coating portion 146b.

[0203] The first non-coating portion 146a is disposed on the first electrode 40 and may include a plurality of segments 40c. The second non-coating portion 146b is disposed on the second electrode 50 and may include a plurality of segments 50c.

[0204] The first uncoated portion 146a and the second uncoated portion 146b do not include a portion near the core. Therefore, the core 112 of the electrode assembly 110 is not enclosed by the first bent surface area F1 and the second bent surface area F2. Therefore, there is no difficulty in the electrolyte injection process, and the welding process between the first current collecting plate 144 and the battery case 142 can be easily performed by passing the welding jig through the core 112.

[0205] The sealing body 143 may include a cap plate 143 a , a first gasket 143 b for providing airtightness and insulation between the cap plate 143 a and the battery case 142 , and a connection plate 143 c electrically and mechanically coupled to the cap plate 143 a .

[0206] The cap plate 143a is a member made of a conductive metal material and covers the top open end of the battery case 142. The cap plate 143a is electrically connected to the second bent surface region F2 of the second electrode 50 and is electrically insulated from the battery case 142 by the first gasket 143b. Therefore, the cap plate 143a can serve as the positive electrode terminal of the cylindrical battery 190.

[0207] The cover plate 143a is placed on the curling portion 147 formed on the battery case 142 and fixed by the pressing portion 148. A first gasket 143b may be interposed between the cover plate 143a and the pressing portion 148 to ensure the airtightness of the battery case 142 and the electrical insulation between the battery case 142 and the cover plate 143a. The cover plate 143a may have a protrusion 143d protruding upward from the center thereof.

[0208] The battery case 142 is electrically connected to the first bent surface region F1 of the first electrode 40. Therefore, the battery case 142 may have the same negative polarity as the first electrode 40.

[0209] The battery case 142 includes a bead portion 147 and a press portion 148 at the top thereof. The bead portion 147 is formed by pressing the periphery of the outer peripheral surface of the battery case 142 inward. The bead portion 147 prevents the electrode assembly 110 housed inside the battery case 142 from falling out through the top opening of the battery case 142 and can also serve as a support portion on which the sealing body 143 is placed.

[0210] The second non-coating portion 146b of the second electrode 40 does not include a portion near the periphery of the electrode assembly 110. Therefore, when the battery case 142 is pressed inward from the outside to form the beading portion 147, the upper end of the periphery of the electrode assembly 110 can be prevented from being deformed.

[0211] The beading portion 148 is formed on the curling portion 147. The beading portion 148 has an extended bent shape to cover the outer periphery of the cover plate 143a provided on the curling portion 147 and a portion of the upper surface of the cover plate 143a.

[0212] The cylindrical battery 190 may further include a first current collecting plate 144 and / or a second current collecting plate 145 and / or an insulator 146 .

[0213] The first current collecting plate 144 is made of a conductive metal material and may be coupled to the lower surface of the electrode assembly 110. One surface of the first current collecting plate 144 may be coupled to the first bent surface region F1 of the first electrode 40 by welding, and the opposite surface may be coupled to the inner bottom surface of the battery case 142 by welding.

[0214] The first current collecting plate 144 may be omitted. In this case, the first bent surface area F1 may be welded to the bottom surface of the battery case 142 .

[0215] The second current collecting plate 145 is made of a conductive metal material and is coupled to the upper portion of the electrode assembly 110. The second current collecting plate 145 is coupled to the second bent surface region F2 of the second electrode 50 by welding. A lead 149 may be connected to the second current collecting plate 145. The lead 149 may extend upward from the electrode assembly 110 and be coupled to the connection plate 143c, or may be directly coupled to the lower surface of the cap plate 143a.

[0216] The second current collecting plate 145 may be integrally formed with the lead 149. In this case, the lead 149 may have an elongated plate shape extending outward from near the center of the second current collecting plate 145.

[0217] The insulator 146 is made of an insulating polymer resin and may cover the second current collecting plate 145. The insulator 146 may cover the second current collecting plate 145 located on its upper surface, thereby preventing direct contact between the second current collecting plate 145 and the inner circumference of the battery case 142.

[0218] The insulator 146 has a lead hole 151 so that the lead 149 extending upward from the second current collecting plate 145 can be drawn out through the lead hole 151. The lead 149 is pulled upward through the lead hole 151 and coupled to the lower surface of the connection plate 143c or the lower surface of the cap plate 143a.

[0219] The peripheral area of ​​the edge of the insulator 146 can be interposed between the second current collecting plate 145 and the beading portion 147 to fix the coupled body of the electrode assembly 110 and the second current collecting plate 145. Therefore, the movement of the coupled body of the electrode assembly 110 and the second current collecting plate 145 can be restricted in the height direction Y of the battery 190, thereby improving the assembly stability of the battery 190.

[0220] The battery case 142 may also include a vent 152 formed on its lower surface. The vent 152 corresponds to an area having a smaller thickness than the peripheral area of ​​the lower surface of the battery case 142. The vent 152 is structurally weaker than the surrounding area. Therefore, when an abnormality occurs in the cylindrical battery 190 and the internal pressure increases to above a predetermined level, the vent 152 may rupture, thereby discharging the gas generated inside the battery case 142 to the outside.

[0221] The vent portion 152 may be formed continuously or discontinuously while rounding the lower surface of the battery case 142. In one modification, the vent portion 152 may be formed in a straight line pattern or other patterns.

[0222] Figure 13 2 is a cross-sectional view showing a cylindrical battery 200 according to an embodiment of the present disclosure, taken along a winding axis direction Y. FIG.

[0223] Reference Figure 13 The structure of the electrode assembly of the cylindrical battery 200 is similar to Figure 12 The structure of the cylindrical battery 190 in FIG. 1 is basically the same, and other structures except the electrode assembly are changed.

[0224] Specifically, the cylindrical battery 200 includes a battery case 171 through which a rivet terminal 172 is mounted. The rivet terminal 172 is mounted through a perforation formed in the closed end of the battery case 171. The rivet terminal 172 is riveted to the perforation of the battery case 171 with a second gasket 173 made of an insulating material interposed therebetween. The rivet terminal 172 is exposed to the outside in a direction opposite to the direction of gravity.

[0225] The riveted terminal 172 includes a terminal exposure portion 172a and a terminal insertion portion 172b. The terminal exposure portion 172a is exposed to the exterior of the closed surface of the battery housing 171. The terminal exposure portion 172a may be located approximately in the center of the closed end of the battery housing 171. The maximum diameter of the terminal exposure portion 172a may be larger than the maximum diameter of the perforation formed in the battery housing 171. The terminal insertion portion 172b may be electrically connected to the uncoated portion 146b of the second electrode 50 through the approximately center of the closed end of the battery housing 171. The lower edge of the terminal insertion portion 172b may be riveted to the inner surface of the battery housing 171. In other words, the lower edge of the terminal insertion portion 172b may have a shape that curves toward the inner surface of the battery housing 171. A flat portion 172c is included on the inner side of the lower edge of the terminal insertion portion 172b. The maximum diameter of the lower portion of the riveted terminal insertion portion 172b may be larger than the maximum diameter of the perforation of the battery housing 171.

[0226] The flat portion 172 c of the terminal insertion portion 172 b may be welded to a central portion of the second current collecting plate 145 coupled to the second bending surface region F2 of the second electrode 50 .

[0227] An insulator 174 made of an insulating material may be interposed between the second current collecting plate 145 and the inner surface of the battery case 171. The insulator 174 covers the upper portion of the second current collecting plate 145 and the top edge of the electrode assembly 110. Thus, the uncoated portion 146b of the second electrode 50 of the electrode assembly 110 may be prevented from contacting the inner surface of the battery case 171 having a different polarity and causing a short circuit.

[0228] The thickness of the insulator 174 corresponds to or is slightly greater than the distance between the upper surface of the second current collecting plate 145 and the inner surface of the closed end of the battery case 171. Therefore, the insulator 174 can contact the upper surface of the second current collecting plate 145 and the inner surface of the closed end of the battery case 171.

[0229] The terminal insertion portion 172b of the rivet terminal 172 can be welded to the second current collecting plate 145 through the perforation of the insulator 174. The diameter of the perforation formed in the insulator 174 can be larger than the diameter of the rivet portion located at the lower end of the terminal insertion portion 172b. Preferably, the perforation can expose the lower portion of the terminal insertion portion 172b and the second gasket 173.

[0230] The second gasket 173 is interposed between the battery case 171 and the rivet terminal 172 to prevent the battery case 171 and the rivet terminal 172 having opposite polarities from electrically contacting each other. Therefore, the upper surface of the battery case 171 having a substantially flat shape can serve as the negative terminal of the cylindrical battery 200.

[0231] The second gasket 173 includes a gasket exposed portion 173a and a gasket inserted portion 173b. The gasket exposed portion 173a is interposed between the terminal exposed portion 172a of the riveted terminal 172 and the battery case 171. The gasket inserted portion 173b is interposed between the terminal inserted portion 172b of the riveted terminal 172 and the battery case 171. When the terminal inserted portion 172b is riveted, the gasket inserted portion 173b can be deformed together, thereby closely contacting the inner surface of the battery case 171. The second gasket 173 can be made of, for example, a polymer resin having insulating properties.

[0232] The washer exposed portion 173a of the second washer 173 may have an extended shape to cover the outer periphery of the terminal exposed portion 172a of the riveted terminal 172. When the second washer 173 covers the outer periphery of the riveted terminal 172, it is possible to prevent a short circuit from occurring when an electrical connection component such as a bus bar is coupled to the battery housing 171 and / or the upper surface of the riveted terminal 172. Although not shown in the drawings, the washer exposed portion 173a may have an extended shape to cover not only the outer peripheral surface of the terminal exposed portion 172a but also a portion of its upper surface.

[0233] When the second gasket 173 is made of a polymer resin, the second gasket 173 can be coupled to the battery case 171 and the riveted terminal 172 by heat fusion. In this case, the airtightness at the coupling interface between the second gasket 173 and the riveted terminal 172 and the coupling interface between the second gasket 173 and the battery case 171 can be enhanced. At the same time, when the gasket exposed portion 173a of the second gasket 173 has a shape extending to the upper surface of the terminal exposed portion 172a, the riveted terminal 172 can be integrally coupled to the second gasket 173 by insert injection molding.

[0234] In the upper surface of the battery case 171 , a remaining area 175 excluding the area occupied by the rivet terminal 172 and the second gasket 173 corresponds to a negative terminal having a polarity opposite to that of the rivet terminal 172 .

[0235] The first current collecting plate 144 is electrically connected to the first bent surface region F1 of the first electrode 40 by welding at a lower portion of the electrode assembly 110 .

[0236] Preferably, the first current collecting plate 144 is electrically connected to the battery housing 171. To this end, at least a portion of the edge of the first current collecting plate 144 can be inserted and fixed between the inner surface of the battery housing 171 and the first gasket 178b. In one example, at least a portion of the edge of the first current collecting plate 144 can be fixed to the bead portion 180 by welding while being supported on the lower surface of the bead portion 180 formed at the bottom of the battery housing 171. In one variation, at least a portion of the edge of the first current collecting plate 144 can be directly welded to the inner wall surface of the battery housing 171.

[0237] The sealing body 178 for sealing the lower open end of the battery housing 171 includes a cover plate 178a and a first gasket 178b. The first gasket 178b electrically separates the cover plate 178a from the battery housing 171. The edge of the pressure part 181 fixes the edge of the cover plate 178a and the first gasket 178b together. The cover plate 178a has a vent portion 179. The configuration of the vent portion 179 is the same as that in the Figure 12The embodiment shown is substantially the same. The lower surface of the cover plate 178a can be located above the lower end of the edge pressing portion 181. In this case, a space is formed below the cover plate 178a to facilitate exhaust. This is particularly useful when installing the cylindrical battery 200 so that the edge pressing portion 181 faces the direction of gravity.

[0238] Preferably, the cover plate 178a is made of a conductive metal material. However, since the first gasket 178b is interposed between the cover plate 178a and the battery housing 171, the cover plate 178a does not need to have an electrical polarity. The seal 178 seals the open end of the lower portion of the battery housing 171 and is primarily used to discharge gas when the internal pressure of the battery 200 increases above a critical value.

[0239] In a modified embodiment, the edge of the cover plate 178a can be directly connected to the open end of the battery housing 171 by welding. In this case, the curling portion 180 and the pressing portion 181 can be omitted, and the side wall of the battery housing 171 can extend linearly to the open end. In addition, at least a portion of the edge of the first current collecting plate 144 can be connected to the cover plate 178a. In one example, the edge of the cover plate 178a, the open end of the battery housing 171, and the edge of the first current collecting plate 144 can be connected by welding. In another example, at least a portion of the edge of the first current collecting plate 144 can be directly welded to the inner wall surface of the battery housing 171. In another example, the first current collecting plate 144 can be omitted, and the portion of the cover plate 178a facing the first bending surface area F1 can be directly welded to the first bending surface area F1, while the edge of the cover plate 178a can be welded to the open end of the battery housing 171. The portion of the cover plate 178a can be the inner side of the edge.

[0240] Preferably, the rivet terminal 172 electrically connected to the second bent surface area F2 of the second electrode 50 serves as a positive terminal. In addition, in the upper surface of the battery case 171 electrically connected to the first bent surface area F1 of the first electrode 40 through the first current collecting plate 144, the portion 175 other than the rivet terminal 172 serves as a negative terminal. If the two electrode terminals are located at the upper portion of the cylindrical battery 200 as described above, an electrical connection component such as a bus bar can be arranged only on one side of the cylindrical battery 200. This can lead to a simplification of the battery pack structure and an improvement in energy density. In addition, since the portion 175 serving as the negative terminal has a substantially flat shape, a sufficient connection area can be ensured to connect an electrical connection component such as a bus bar. Therefore, the cylindrical battery 200 can reduce the resistance at the connection portion of the electrical connection component to a desired level.

[0241] The cylindrical batteries can be used to manufacture battery packs.

[0242] Figure 14is a diagram schematically illustrating a battery pack according to an embodiment of the present disclosure.

[0243] Reference Figure 14 The battery pack 300 according to an embodiment of the present disclosure includes an assembly in which cylindrical batteries 301 are electrically connected, and a battery pack housing 302 for accommodating the assembly. The cylindrical batteries 301 may be any of the batteries according to the above-described embodiments. In the figure, for ease of illustration, components such as bus bars for electrical connection of the cylindrical batteries 301, a cooling unit, and external terminals are not shown.

[0244] The battery pack 300 can be mounted on a vehicle. The vehicle can be, for example, an electric vehicle, a hybrid electric vehicle, or a plug-in hybrid vehicle. The vehicle includes a four-wheeled vehicle or a two-wheeled vehicle.

[0245] Figure 15 It is schematically shown including Figure 14 FIG. 3 shows a diagram of a battery pack 300 for a vehicle.

[0246] Reference Figure 15 , the vehicle V according to the embodiment of the present disclosure includes the battery pack 300 according to the embodiment of the present disclosure. The vehicle V runs by receiving power from the battery pack 300 according to the embodiment of the present disclosure.

[0247] According to the present disclosure, the connection position of the fixing member is optimized by utilizing the distance between the winding end of the diaphragm and the winding end of the outermost coating portion along the winding direction, the distance between the end of the diaphragm and the end of the outermost coating portion in the axial direction of the electrode assembly, and the minimum folding angle of the winding end angle of the diaphragm. Even when the winding end angle of the diaphragm is folded outward to the maximum extent with the end of the fixing member as the folding bias point, the outermost coating portion can be fundamentally prevented from being exposed.

[0248] According to another aspect of the present disclosure, by optimizing the design of the attachment position of the fixing member, the distance between the winding end of the diaphragm and the winding end of the outermost coating portion along the winding direction can be reduced compared with the prior art, thereby reducing the amount of diaphragm used in the winding process of the electrode assembly.

[0249] According to yet another aspect of the present disclosure, a cylindrical battery having improved safety, a battery pack, and a vehicle including the same may be provided by fundamentally preventing exposure of an outermost coating portion that may occur while operating an electrode assembly during assembly of the cylindrical battery.

[0250] 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 present disclosure, are given by way of illustration only, as various changes and modifications within the scope of the present disclosure will become apparent to those skilled in the art from this detailed description.

Claims

1. An electrode assembly, wherein a first electrode and a second electrode and a separator interposed between the first electrode and the second electrode are wound around an axis to define a core portion and an outer periphery, the first electrode and the second electrode having short sides and long sides and including a coated portion and an uncoated portion along the long side direction, in, The outermost coating portion of the electrode assembly is the coating portion of the first electrode, The winding end of the separator extends from the winding end of the coating portion of the first electrode along the winding direction by a first length. wherein a fixing member is attached to the coiled end of the diaphragm in the axial direction from a point spaced apart from the axial end of the diaphragm by a second length, wherein the axial end of the coating portion of the first electrode is spaced inwardly from the axial end of the diaphragm by a third length, and When the winding end corner of the separator is folded to the maximum extent with the axial end of the fixing member as a folding bias point so that the outer surface of the winding end corner faces the outer periphery, the winding end corner of the coating portion of the first electrode is not exposed to the outside.

2. The electrode assembly according to claim 1, in, A folding line generated when the winding end corner of the separator is folded does not overlap with the winding end corner of the coating portion of the first electrode.

3. The electrode assembly according to claim 2, in, When the angle of the wound end of the diaphragm is folded outward as much as possible using any point of the wound end of the diaphragm as a folding bias point, the surface portion corresponding to the portion exposed to the outside is approximately a right triangle, and the minimum value of the angle formed by one side of the right triangle along the winding direction and the folding line is defined as the minimum folding angle (θ min ),and wherein the fixing member is attached to the wound end of the diaphragm such that a second length corresponding to a distance between an axial end of the fixing member and an axial end of the diaphragm satisfies the following formula: Second length < third length + first length * tan(θ min ).

4. The electrode assembly according to claim 3, in, The minimum folding angle (θ min ) decreases as the diameter of the electrode assembly increases.

5. The electrode assembly according to claim 4, in, The minimum folding angle (θ min ) decreases exponentially with increasing diameter of the electrode assembly.

6. The electrode assembly according to claim 3, in, A length of one side of the right triangle in the winding direction is longer than a length of another side of the right triangle in the axial direction.

7. The electrode assembly according to claim 3, in, The diameter of the electrode assembly is 13 mm to 103 mm, and Wherein, the minimum folding angle (θ min ) is 5 to 60 degrees.

8. The electrode assembly according to claim 3, in, The first length is 1 mm to 120 mm.

9. The electrode assembly according to claim 3, in, The third length is 0.1 mm to 3.0 mm.

10. The electrode assembly according to claim 1, in, The separator includes an inner separator interposed between the first electrode and the second electrode, and an outer separator arranged outside the first electrode and winding a stack of the first electrode, the inner separator, and the second electrode, and The separator extending from the winding end of the coating portion of the first electrode along the winding direction by the first length is the external separator.

11. The electrode assembly according to claim 1, in, The uncoated portion of the first electrode includes a plurality of segments divided by cutting grooves formed along the winding direction, wherein the plurality of segments of the first electrode protrude outward from an axial end of the diaphragm in a direction away from an axial end of the coating portion of the first electrode, and The multiple segments of the first electrode are bent toward the core to form a first bent surface area.

12. The electrode assembly according to claim 10, in, The uncoated portion of the second electrode includes a plurality of segments divided by cutting grooves formed along the winding direction, wherein the plurality of segments of the second electrode protrude outward from an axial end of the diaphragm adjacent to an axial end of the coating portion of the first electrode, and The plurality of segments of the second electrode are bent toward the core to form a second bent surface region.

13. A cylindrical battery, comprising: The electrode assembly according to any one of claims 1 to 12; a battery housing having an open end and a closed end and configured to accommodate the electrode assembly through the open end, the battery housing being electrically connected to the first electrode of the electrode assembly; a sealing body configured to seal the open end of the battery housing; as well as A terminal is electrically connected to the second electrode of the electrode assembly and has a surface exposed to the outside of the battery case.

14. The cylindrical battery according to claim 13, further comprising: A first current collecting plate is configured to electrically connect the uncoated portion of the first electrode and the battery case.

15. The cylindrical battery according to claim 14, in, The sealing body includes a cover plate configured to cover the open end of the battery case, and a gasket interposed between an edge of the cover plate and the open end, and Wherein, the edge of the first current collecting plate is interposed between the gasket and the side wall of the battery housing.

16. The cylindrical battery according to claim 15, in, The battery case includes a bead portion formed by pressing the outer periphery near the open end inward, and Wherein, the edge of the first current collecting plate contacts the curling portion.

17. The cylindrical battery according to claim 13, in, The terminal is installed in a through hole formed in the closed end of the battery case to be insulated from the battery case, wherein the terminal comprises a terminal exposure portion exposed through the outer surface of the closed end, and a terminal insertion portion extending from the terminal exposure portion and inserted into the battery case through the through hole, and Wherein, the lower edge of the terminal insertion portion is riveted toward the inner surface of the closed end.

18. The cylindrical battery according to claim 17, further comprising: A second current collecting plate is configured to electrically connect the uncoated portion of the second electrode and a lower end of the terminal insertion portion.

19. The cylindrical battery according to claim 13, in, The sealing body includes a cover plate that seals the open end of the battery housing, and Wherein, the terminal is the cover plate.

20. The cylindrical battery according to claim 13, in, The sealing body includes a cover plate covering the open end of the battery housing, wherein the edge of the cover plate is coupled to the open end, and At least a portion of the first current collecting plate is coupled to the cover plate.

21. The cylindrical battery according to claim 13, in, The sealing body includes a cover plate configured to cover the open end of the battery housing, wherein the edge of the cover plate is coupled to the open end of the battery housing, and Wherein, at least a portion of an inner side of the edge of the cover plate is electrically connected to the electrode assembly. 22 . A battery pack comprising a plurality of cylindrical batteries, wherein the cylindrical batteries are the cylindrical batteries according to claim 13 .

23. A vehicle comprising the battery pack according to claim 22.

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