Electrode assembly, battery, battery pack including same, and automobile

Abstract

The present invention discloses an electrode assembly, a battery, a battery pack including the same, and an automobile. A first electrode of the electrode assembly includes a first active material portion coated with an active material layer along a winding direction and a first uncoated portion not coated with an active material layer, at least a portion of the first uncoated portion is defined as an electrode tab, the first uncoated portion includes a plurality of segments that can be independently bent along the winding direction and are exposed to the outside of a separator, the plurality of segments are aligned along a radial direction of the electrode assembly to form a plurality of segment alignment portions spaced apart in a circumferential direction, and between adjacent segment alignment portions in the circumferential direction, ends of the first active material portion include electrolyte-impregnated portions exposed between the winding turns of the separator.

Description

[Technical Field]

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

[0002] This application claims priority based on Korean Patent Application No. 10-2021-0160490 filed on November 19, 2021, and Korean Patent Application No. 10-2021-0160823 filed on November 19, 2021, and the contents disclosed in the specifications and drawings of those applications are incorporated into this application in their entirety. [Background technology]

[0003] Secondary batteries, which have high applicability to each product group and electrical properties such as high energy density, are commonly used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) that are driven by electrical sources.

[0004] These secondary batteries not only have the primary advantage of dramatically reducing the use of fossil fuels, but are also environmentally friendly as they do not produce any by-products from energy use, and are attracting attention as a new energy source for improving energy efficiency.

[0005] Currently, secondary batteries such as lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries are widely used. The operating voltage of such unit secondary battery cells, i.e., unit batteries, is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, a battery pack is constructed by connecting multiple batteries in series. Alternatively, a battery pack may be constructed by connecting multiple batteries in parallel depending on the required charge / discharge capacity of the battery pack. Therefore, the number of batteries included in the battery pack and the electrical connection configuration can be variously set depending on the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, known types of unit secondary battery cells include cylindrical, prismatic, and pouch-type batteries. In cylindrical batteries, a separator, an insulator, is interposed between a positive electrode and a negative electrode, which is then wound up to form a jelly-roll-type electrode assembly. This assembly is then inserted into a battery housing to complete the battery. Strip-shaped electrode tabs are connected to the uncoated portions of the positive and negative electrodes, electrically connecting the electrode assembly to the electrode terminals exposed to the outside. For reference, the positive electrode terminal is a cap plate of a sealing body that seals the opening of the battery housing, and the negative electrode terminal is the battery housing. However, conventional cylindrical batteries with this structure suffer from problems such as high resistance, excessive heat generation, and poor current collection efficiency due to current concentration at the strip-shaped electrode tabs connected to the positive electrode uncoated portion and / or negative electrode uncoated portion.

[0007] Resistance and heat generation are not major issues with small cylindrical batteries with form factors such as 1865 and 2170. However, when the form factor of cylindrical batteries is increased to be used in electric vehicles, a large amount of heat is generated around the electrode tabs during the fast charging process, which can cause the cylindrical battery to catch fire.

[0008] To solve this problem, a cylindrical battery (so-called tab-less cylindrical battery) has been proposed, which has a structure in which positive and negative electrode uncoated areas are located at the top and bottom of a jelly-roll type electrode assembly, respectively, and current collector plates are welded to these uncoated areas to improve current collection efficiency.

[0009] Figures 1 to 3 show the manufacturing process of a tabless cylindrical battery. Figure 1 shows the structure of the electrode, Figure 2 shows the electrode winding process, and Figure 3 shows the process of welding a current collector plate to the folded surface area of ​​the uncoated portion.

[0010] 1 to 3, a positive electrode 10 and a negative electrode 11 have a structure in which an active material 21 is coated on a current collector sheet 20, and include a non-coating portion 22 on one long side along the winding direction (X-axis). The long side refers to the side that is parallel to the X-axis direction and has a relatively long length.

[0011] The electrode assembly A is fabricated by stacking a positive electrode 10 and a negative electrode 11 together with two separators 12 in order as shown in Fig. 2, and then winding the stack in one direction (X-axis direction). At this time, the uncoated portion of the positive electrode 10 and the uncoated portion of the negative electrode 11 are arranged in opposite directions.

[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. Thereafter, the current collector plates 30 and 31 are welded to the uncoated portions 10a and 11a, respectively.

[0013] No separate electrode tabs are attached to the positive electrode uncoated region 10a and the negative electrode uncoated region 11a, and current collector plates 30 and 31 are connected to external electrode terminals, forming a current path with a large cross-sectional area along the winding axis direction of electrode assembly A (see arrow), which has the advantage of reducing battery resistance, since resistance is inversely proportional to the cross-sectional area of ​​the path through which current flows.

[0014] In a tabless cylindrical battery, in order to improve the welding characteristics between the uncoated portions 10a, 11a and the current collector plates 30, 31, strong pressure must be applied to the welding areas of the uncoated portions 10a, 11a to bend them as flat as possible.

[0015] However, when the welding area of ​​the uncoated portions 10a, 11a is bent, the patterns of the uncoated portions 10a, 11a may be deformed and distorted irregularly. In this case, the deformed portion may come into contact with an electrode of the opposite polarity, causing an internal short circuit, or may induce microcracks in the uncoated portions 10a, 11a.

[0016] Furthermore, if the electrode assembly is manufactured with the uncoated portions 10a and 11a folded, the processability of the electrolyte injection process that is carried out after the electrode assembly is inserted into a battery housing is reduced.Because there are insufficient gaps on the folded surfaces of the uncoated portions 10a and 11a, it takes a long time for the electrolyte to penetrate into the internal space of the electrode assembly.

[0017] Therefore, it is necessary to improve the structure of the uncoated portions 10a and 11a so as to improve the folding quality of the uncoated portions 10a and 11a and improve the electrolyte impregnation rate. Summary of the Invention [Problem to be solved by the invention]

[0018] The present invention has been made in light of the background of the prior art described above, and aims to provide an electrode assembly having an improved uncoated portion structure that can alleviate stress applied to the uncoated portions exposed at both ends of the electrode assembly when the uncoated portions are bent.

[0019] Another object of the present invention is to provide an electrode assembly in which a plurality of segments are applied to an uncoated portion of an electrode, and when the electrode is wound up, the segments are aligned in a predetermined direction, and in areas where no segments are arranged, ends of an active material layer formed on the electrode are exposed, thereby increasing the impregnation rate of an electrolyte.

[0020] It is yet another object of the present invention to provide an electrode assembly in which the electrolyte injection passage is not blocked even when the uncoated portion is folded.

[0021] Another object of the present invention is to provide an electrode assembly in which the physical properties of the welding area are improved by applying a segment structure to the uncoated portion of the electrode and sufficiently increasing the number of segments stacked in the area used as the welding target area.

[0022] Another object of the present invention is to provide an electrode assembly in which a current collector plate is welded to a bent surface area formed by bending a segment, thereby improving energy density and reducing resistance.

[0023] It is yet another object of the present invention to provide a battery including terminals and current collectors with improved designs that allow electrical wiring to be performed at the top.

[0024] It is yet another object of the present invention to provide a battery including an electrode assembly with an improved structure, a battery pack including the same, and a vehicle including the battery pack.

[0025] The technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems will be clearly understood by those skilled in the art from the following description of the invention. [Means for solving the problem]

[0026] To achieve the above object, one aspect of the present invention provides an electrode assembly in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed between the first and second electrodes around a winding shaft, wherein the first electrode includes a first active material portion coated with an active material layer along the winding direction, and a first uncoated portion not coated with the active material layer, the first uncoated portion including a plurality of segments that can be independently bent along the winding direction and exposed to the outside of the separator, the plurality of segments being aligned and overlapping along the radial direction of the electrode assembly to form a plurality of segment alignment portions spaced apart in the circumferential direction, and an electrolyte-impregnated portion where an end of the first active material portion is exposed between the wound turns of the separator between adjacent segment alignment portions in the circumferential direction.

[0027] When multiple segments included in the segment alignment section overlap in the radial direction, this means that when a specified straight line is drawn from the center of the core through the segment alignment section, all of the segments intersect with the line.

[0028] Preferably, the segments constituting each segment alignment portion may be defined as electrode tabs when bent along the radial direction of the electrode assembly.

[0029] The plurality of segment alignment portions may extend radially along the radial direction of the electrode assembly.

[0030] The plurality of segment alignment portions may be arranged at equal intervals along the circumferential direction of the electrode assembly.

[0031] The angle between adjacent segment alignment portions in the circumferential direction of the electrode assembly may be 90°, 120°, or 180°.

[0032] The plurality of segments may have the same length in the winding direction.

[0033] The lengths of the plurality of segments in the winding direction may gradually increase from the core side toward the outer periphery side.

[0034] The plurality of segment alignment portions may have a rectangular or sector shape when viewed from the winding axis direction of the electrode assembly.

[0035] When viewed from the winding axis direction of the electrode assembly, the area of ​​the electrolyte-impregnated portion may be larger than the area of ​​the plurality of segment alignment portions.

[0036] In a cross section of the electrolyte impregnation unit cut along the winding shaft, an end of the first active material unit may be spaced inward of the electrode assembly relative to an end of the separator.

[0037] The distance between the end of the first active material portion and the end of the separator may be 0.6 mm to 1.0 mm.

[0038] The winding direction length and pitch of the plurality of segment pieces can be assigned values ​​that are approximately the same as values ​​mathematically designed using the winding direction length of the segment pieces, which is predetermined based on an approximate winding turn structure in which semicircles with periodically increasing radii are connected in the winding direction, and the angle between adjacent segment piece alignment portions in the circumferential direction.

[0039] The n+1th pitch D adjacent to the n+1th segment along the winding direction n+1 may be assigned a value approximately equal to the value determined using Equation 1 below.

[0040] [Formula 1] Case 1:D n+1 =θ Dn+1 *R n+1 =(90°-θ An+1 )*R n+1 Case 2:D n+1 =θ Dn+1 *(R n +R n+1 ) / 2=(90°-θ An+1 )*(R n +R n+1 ) / 2 (n is an integer equal to or greater than 0; the starting point of the first semicircle corresponds to the position of the first segment in the winding direction; R n is the radius of the nth semicircle; R n+1 is the radius of the n+1th semicircle; θ An+1 is the inscribed angle of the n+1th segment; θ Dn+1 is the inscribed angle for the pitch of the n+1th segment; the formula for Case 1 is the n+1th pitch D n+1 The formula applies when the arc corresponding to is located on the n+1th semicircle; the formula for case 2 is the n+1th pitch D n+1 (The formula applies when the arc corresponding to is located between the nth semicircle and the n+1th semicircle.)

[0041] The radius of the semicircle may increase by Δ / 2 (Δ is the symbol representing the spacing between adjacent winding turns) every ½ winding turn.

[0042] The symbol Δ may be assigned a value that is approximately equal to the sum of the thickness of one positive electrode, the thickness of one negative electrode, and the thickness of two separators.

[0043] A cutting groove is interposed between adjacent pieces in the winding direction, and the lower part of the cutting groove may include a bottom portion and rounded portions connecting both ends of the bottom portion to the side edges of the pieces on both sides of the cutting groove.

[0044] The bottom of the cut groove may be spaced a predetermined distance from the active material layer.

[0045] The distance between the lower end of the cutting groove and the active material layer may be 0.2 mm to 4 mm.

[0046] An insulating coating layer may be formed at a boundary between the active material layer and a non-coating region in a section where the bottom of the cut groove and the active material layer are separated.

[0047] The plurality of segment alignment portions may include a radial section in which the height of the segments increases from a core side to an outer periphery side of the electrode assembly.

[0048] The plurality of segment alignment portions have segment heights ranging from a first height h1 to an (N-1)th height h from the core side to the outer periphery side of the electrode assembly. N-1 (N is a natural number greater than or equal to 3) and the variable height section, N height h N (h N-1 The height may include a uniform section where the height is maintained uniform (larger than the width of the base).

[0049] Height h k (k is a natural number from 1 to N) The starting radius of the winding turn containing the segment is r k When the core of the electrode assembly is defined as k More than 90% of the diameter is not blocked by the bend in the segment located at the center.

[0050] Height h k (k is a natural number from 1 to N) The starting radius of the winding turn containing the segment is r k, the radius of the core is r c Then, the height of the segment h k may satisfy the following formula 2.

[0051] [Formula 2] 2mm≦h k ≦r k -α*r c (a is 0.90 to 1)

[0052] The plurality of segment alignment portions may include, in order along the radial direction based on a cross section along the winding axis, a segment omission section where no segments are present, a height variable section where the height of the segments varies, and a height uniform section where the height of the segments is uniform, and the plurality of segment alignment portions may be arranged in the height variable section and the height uniform section, and may be bent along the radial direction of the electrode assembly to form a bent surface region extending along the radial direction.

[0053] When the number of segments intersecting a virtual line parallel to the winding axis direction at any radial position of the folded surface region relative to the center of the core of the electrode assembly is defined as the number of stacked segments at the corresponding radial position, the folded surface region may include a uniform stack number section in which the number of stacked segments is uniform from the core side toward the outer periphery, and a decreasing stack number section located outside the uniform stack number section in which the number of stacked segments decreases toward the outer periphery.

[0054] The number of stacked pieces in the uniform stacking section may be 10 to 35.

[0055] The first electrode may be a positive electrode, and the thickness of the divided pieces in the uniform stacking number section may be 100 μm to 875 μm.

[0056] The first electrode may be a negative electrode, and the thickness of the divided pieces in the uniform stacking number section may be 50 μm to 700 μm.

[0057] The second electrode includes a second active material portion coated with an active material layer along the winding direction, and a second uncoated portion not coated with an active material layer, the second uncoated portion including a plurality of segments that can be independently bent along the winding direction and are exposed to the outside of the separator, the plurality of segments of the second uncoated portion being aligned along the radial direction of the electrode assembly to form a plurality of segment alignment portions spaced apart in the circumferential direction, and an electrolyte-impregnated portion where an end of the second active material portion is exposed between the wound turns of the separator between adjacent segment alignment portions in the circumferential direction of the second uncoated portion may be included.

[0058] To achieve the above object, a battery according to another aspect of the present invention is an electrode assembly in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed between the first and second electrodes around a winding shaft, the first electrode including a first active material portion coated with an active material layer along the winding direction and a first uncoated portion not coated with the active material layer, the first uncoated portion including a plurality of segments independently bendable along the winding direction and exposed to an outside of the separator, the plurality of segments overlapping along a radial direction of the electrode assembly, The battery includes: an electrode assembly in which the first active material portion is aligned to form a plurality of segment alignment portions spaced apart in the circumferential direction, and an electrolyte-impregnated portion in which an end of the first active material portion is exposed between the wound turns of the separator between adjacent segment alignment portions in the circumferential direction; a battery housing having an open end and a bottom portion opposite the open end, which houses the electrode assembly in the space between the open end and the bottom, and which is electrically connected to one of the first electrode and the second electrode and has a first polarity; a sealing body which seals the open end of the battery housing; and a terminal of a second polarity which is electrically connected to the other of the first electrode and the second electrode and has a surface exposed to the outside.

[0059] The battery may further include a first current collecting plate electrically connected to the first uncoated portion, and the terminal may be a rivet terminal insulatively attached to a through hole formed in a bottom of the battery housing, electrically connected to the first current collecting plate, and having the second polarity.

[0060] The battery may further include an insulator interposed between an inner surface of the bottom of the battery housing and an upper surface of the first current collector plate to electrically insulate the inner surface of the bottom of the battery housing from the first current collector plate.

[0061] The rivet terminal may include a flat portion at a lower end, the insulator may include an opening that exposes the flat portion, and the flat portion may be welded to the first current collector plate through the opening.

[0062] The second electrode may include a second active material portion coated with an active material layer along the winding direction and a second uncoated portion not coated with an active material layer. The second electrode has the first polarity, and at least a portion of the second uncoated portion may itself be defined as an electrode tab. The battery may further include a second current collector plate electrically connected to the second uncoated portion and having at least a portion of its periphery attached to a sidewall of the battery housing.

[0063] The battery housing may include a beading portion pressed inward on an inner wall adjacent to an open end, and a periphery of the second current collector plate may be electrically connected to the beading portion.

[0064] The battery may include a cap plate having a non-polarity and a periphery supported by the beading portion, a gasket interposed between the periphery of the cap plate and an open end of the battery housing, and a crimping portion extending inward from the open end of the battery housing and bent to wrap around and secure the periphery of the cap plate together with the gasket. The periphery of the second current collector plate may be interposed and secured between the beading portion and the gasket by the crimping portion.

[0065] The electrode assembly may include, in order along a radial direction based on a cross section along the winding axis, a segment-free section where no segments exist, a height-variable section where the height of the segments varies, and a uniform height section where the height of the segments is uniform, and the plurality of segments may be arranged in the height-variable section and the uniform height section, and may form a folded surface region as they are folded along the radial direction of the electrode assembly.

[0066] When the number of the segments intersecting a virtual line parallel to the winding axis direction at any radial position of the folded surface region with respect to the center of the core of the electrode assembly as a reference is defined as the number of stacked segments at the corresponding radial position, the folded surface region may include a uniform stack number section in which the number of stacked segments is uniform from the core side to the outer periphery, and a decreasing stack number section located adjacent to the uniform stack number section in which the number of stacked segments decreases with increasing distance from the uniform stack number section.

[0067] The uniform stacking number section may have 10 to 35 stacked pieces.

[0068] The first electrode may be a positive electrode, and the thickness of the divided pieces in the uniform stacking number section may be 100 μm to 875 μm.

[0069] The first electrode may be a negative electrode, and the thickness of the divided pieces in the uniform stacking number section may be 50 μm to 700 μm.

[0070] The battery may further include a current collector plate welded to the bent surface region, and the welded region of the current collector plate may overlap the uniform lamination number section by at least 50% in the radial direction of the electrode assembly.

[0071] The technical object of the present invention is achieved by a battery pack including a plurality of the above-described batteries.

[0072] Preferably, the battery is cylindrical and may have a height to diameter ratio greater than 0.4.

[0073] Preferably, the battery is cylindrical and may be a 46110, 4875, 48110, 4880 or 4680 form factor.

[0074] Preferably, the resistance of the battery may be 4 mΩ or less.

[0075] According to one embodiment, in the battery pack, the plurality of batteries may be arranged in a predetermined number of rows, and the electrode terminals of each battery and the outer surface of the bottom of the battery housing may be arranged to face upward.

[0076] According to another aspect, the battery pack may include a plurality of bus bars connecting a plurality of batteries in series and parallel.

[0077] Preferably, the plurality of bus bars are disposed on top of the plurality of batteries, and each bus bar may include a body portion extending between electrode terminals of adjacent batteries, a plurality of first bus bar terminals extending to one side of the body portion and electrically coupled to the electrode terminals of the batteries located on that side, and a plurality of second bus bar terminals extending to the other side of the body portion and electrically coupled to an outer surface of a bottom of a battery housing of the battery located on that other side.

[0078] The technical object of the present invention is also achieved by a vehicle including the above-mentioned battery pack. [Effects of the Invention]

[0079] According to one aspect of the present invention, the uncoated portions protruding from the upper and lower sides of the electrode assembly are used as electrode tabs, thereby reducing the internal resistance of the battery and increasing the energy density.

[0080] In addition, according to one aspect of the present invention, by improving the structure of the uncoated portion of the electrode assembly, it is possible to prevent the uncoated portion from tearing when being bent, and by sufficiently increasing the number of overlapping layers of the uncoated portion, it is possible to improve the welding strength of the current collector plate.

[0081] In addition, according to one aspect of the present invention, when a plurality of segments are applied to an uncoated portion of an electrode and the electrode is wound up, the plurality of segments are aligned in a predetermined direction, and in areas where no segments are arranged, the ends of the active material layer formed on the electrode are exposed between the wound turns of the separator, thereby increasing the electrolyte impregnation rate.

[0082] Furthermore, according to one aspect of the present invention, by sufficiently increasing the number of stacked pieces in the area used as the welding target area, the physical properties of the area to which the current collector plate is welded can be improved.

[0083] In addition, according to one aspect of the present invention, by applying a structure in which a current collector plate is welded to a folded surface area formed by bending a divided piece, it is possible to provide an electrode assembly with improved energy density and reduced resistance.

[0084] Furthermore, according to one aspect of the present invention, a cylindrical battery with an improved design that allows electrical wiring to be performed at the top can be provided.

[0085] In addition, according to one aspect of the present invention, by improving the structure of the uncoated portion adjacent to the core of the electrode assembly, it is possible to prevent the cavity in the core of the electrode assembly from being blocked when the uncoated portion is bent, thereby facilitating the electrolyte injection process and the welding process between the battery housing (or rivet terminal) and the current collector plate.

[0086] According to another aspect of the present invention, a cylindrical battery having a structure in which internal resistance is low, internal short circuits are prevented, and welding strength between the current collector plate and the uncoated portion is improved, and a battery pack and a vehicle including the same can be provided.

[0087] In particular, the present invention can provide a cylindrical battery having a height-to-diameter ratio of 0.4 or more and a resistance of 4 mΩ or less, a battery pack including the same, and a vehicle.

[0088] The present invention also provides various other effects, which will be described later with reference to the embodiments, but explanations of effects that can be easily inferred by ordinary skilled artisans will be omitted.

[0089] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited to only the matters described in the drawings. [Brief explanation of the drawings]

[0090] [Figure 1] 1 is a plan view showing the structure of an electrode used in manufacturing a conventional tabless cylindrical battery. [Figure 2] 1 is a diagram showing the electrode winding process of a conventional tabless cylindrical battery. [Figure 3] 1 is a diagram showing a process of welding a current collector plate to a folded surface area of ​​a non-coating portion in a conventional tabless cylindrical battery. [Figure 4] 1 is a plan view showing the structure of an electrode according to an embodiment of the present invention; [Figure 5] 1 is a top view of an electrode assembly manufactured by winding a positive electrode and a negative electrode having an electrode structure according to an embodiment of the present invention together with a separator. [Figure 6] 1 is a partial perspective view showing an upper portion of an electrode assembly according to an embodiment of the present invention; [Figure 7] FIG. 6 is a partial cross-sectional view taken along line AA' in FIG. 5. [Figure 8] This is a diagram schematically showing the relationship between the heights h1, h2, h3, and h4 of the segment parts, the core radius rc, and the radii r1, r2, r3, and r4 of the winding turns at which the segment parts begin to appear, according to an embodiment of the present invention. [Figure 9a] FIG. 10 is a diagram illustrating an approximate winding turn structure in which semicircles C1, C2, C3, C4, C5, C6... whose radii increase every 1 / 2 winding turn are continuously connected to determine the pitch of the segment according to an embodiment of the present invention. [Figure 9b]9b is a diagram for deriving a mathematical formula for determining the pitch of a segment using the approximate wound turn structure shown in FIG. 9a according to an embodiment of the present invention. FIG. [Figure 10a] 10 is a top view of an electrode assembly showing the shape of a segment alignment portion according to another embodiment of the present invention; FIG. [Figure 10b] FIG. 10 is a plan view showing the structure of an electrode according to another embodiment of the present invention. [Figure 11] 10A to 10C are diagrams illustrating various modified examples of segmented structures according to the present invention; [Figure 12a] 4 is a schematic diagram illustrating a cross section of a bent surface region formed by bending a segment toward a core of an electrode assembly according to an embodiment of the present invention; [Figure 12b] 10 is a graph showing the results of counting the number of stacked pieces along the radial direction in the folded surface region of the positive electrode formed on the upper part of the electrode assemblies according to Examples 1-1 to 1-7 and a comparative example. [Figure 12c] 10 is a graph showing the results of counting the number of stacked pieces measured along the radial direction in the folded surface region of the positive electrode formed on the upper part of the electrode assembly according to Examples 2-1 to 2-5, Examples 3-1 to 3-4, Examples 4-1 to 4-3, Examples 5-1 and 5-2. [Figure 12d] 10 is a graph showing the results of counting the number of stacked pieces measured along the radial direction in the folded surface region of the positive electrode formed on the upper part of the electrode assemblies according to Examples 6-1 to 6-6 and 7-1 to 7-6. [Figure 12e] 1 is a top view of an electrode assembly showing a uniform lamination number section b1 and a reduced lamination number section b2 in a folded surface region of a segment according to an embodiment of the present invention. [Figure 13] 1 is a cross-sectional view of a jelly-roll type electrode assembly in which electrodes according to an embodiment of the present invention are applied to a first electrode (positive electrode) and a second electrode (negative electrode) taken along the Y-axis direction (winding axis direction). [Figure 14] FIG. 10 is a cross-sectional view of a jelly-roll type electrode assembly in which electrodes according to another embodiment of the present invention are applied to a first electrode (positive electrode) and a second electrode (negative electrode) taken along the Y-axis direction (winding axis direction). [Figure 15]FIG. 10 is a cross-sectional view of a jelly-roll type electrode assembly in which electrodes according to yet another embodiment of the present invention are applied to a first electrode (positive electrode) and a second electrode (negative electrode), taken along the Y-axis direction (winding axis direction). [Figure 16] FIG. 10 is a cross-sectional view of a jelly-roll type electrode assembly in which electrodes according to yet another embodiment of the present invention are applied to a first electrode (positive electrode) and a second electrode (negative electrode), taken along the Y-axis direction (winding axis direction). [Figure 17] 1 is a cross-sectional view of a cylindrical battery according to an embodiment of the present invention taken along the Y-axis direction. [Figure 18] 4 is a cross-sectional view of a cylindrical battery according to another embodiment of the present invention taken along the Y-axis direction. FIG. [Figure 19] 10 is a cross-sectional view of a cylindrical battery according to yet another embodiment of the present invention, taken along the Y-axis direction. [Figure 20] 10 is a cross-sectional view of a cylindrical battery according to yet another embodiment of the present invention, taken along the Y-axis direction. [Figure 21] FIG. 3 is a top view showing the structure of a first current collector plate according to an embodiment of the present invention. [Figure 22] FIG. 4 is a perspective view showing the structure of a second current collecting plate according to an embodiment of the present invention. [Figure 23] FIG. 10 is a top view showing a state in which a plurality of cylindrical batteries are electrically connected. [Figure 24] FIG. 24 is a partially enlarged view of FIG. 23. [Figure 25] 1 is a diagram illustrating a schematic configuration of a battery pack according to an embodiment of the present invention; [Figure 26] 1 is a schematic diagram of a vehicle including a battery pack according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0091] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and phrases used in the specification and claims should not be construed as being limited to their ordinary and dictionary meanings, but should be construed as having meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventors themselves can appropriately define the concepts of terms in order to best describe the invention.

[0092] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted therefor at the time of this application.

[0093] In addition, to facilitate understanding of the invention, the accompanying drawings may not be drawn to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be used to refer to the same components in different embodiments.

[0094] The expression that two comparison objects are identical means that they are "substantially identical." Therefore, "substantially identical" may include deviations that are considered low in the art, for example, deviations within 5%. Furthermore, the expression that a parameter is uniform in a given region means that the parameter is uniform on average in that region.

[0095] Furthermore, the terms "about" or "approximately" refer to cases where there is a deviation of 1%, 2%, 3%, ..., 20%, etc. based on the number to which the term is used.

[0096] Furthermore, although terms such as "first" and "second" are used to indicate various components, these terms are not intended to limit the components. These terms are used merely to distinguish one component from another, and unless otherwise specified, the first component can also be the second component.

[0097] Throughout the specification, unless otherwise stated, each element may be singular or plural.

[0098] When an arbitrary structure is disposed "on (or under)" a component or "above (or below)" a component, it means not only that the arbitrary structure is disposed in contact with the upper surface (or lower surface) of the component, but also that other structures may be interposed between the component and the arbitrary structure disposed above (or below) the component.

[0099] Furthermore, when a component is referred to as being "coupled," "coupled," or "connected" to another component, it does not only mean that the components are directly coupled or connected to each other, but also that other components are "interposed" between the components, or that each component is "coupled," "coupled," or "connected" through other components.

[0100] Throughout the specification, unless otherwise specified, "A and / or B" means A, B, or A and B, and "C to D" means C or more and D or less, unless otherwise specified.

[0101] In this specification, the direction along the length of the winding shaft of the electrode assembly wound into a jelly roll is referred to as the axial direction (Y-axis). The direction surrounding the winding shaft is referred to as the circumferential direction or outer circumferential direction (X-axis). The direction toward or away from the winding shaft is referred to as the radial direction. Of these, the direction toward the winding shaft is particularly referred to as the centripetal direction, and the direction away from the winding shaft is particularly referred to as the centrifugal direction.

[0102] First, an electrode assembly according to an embodiment of the present invention will be described. The electrode assembly is a jelly-roll type electrode assembly having a structure in which a sheet-like first electrode, a sheet-like second electrode, and a separator interposed between the first and second electrodes are wound in one direction.

[0103] Preferably, at least one of the first electrode and the second electrode includes a non-coated portion on a long side edge in the winding direction where no active material is coated, and at least a portion of the non-coated portion itself is used as an electrode tab. That is, no separate strip-shaped tab is provided on the non-coated portion, and only a portion of the non-coated portion is used as the tab.

[0104] FIG. 4 is a plan view showing the structure of an electrode 40 according to one embodiment of the present invention.

[0105] Referring to FIG. 4, the electrode 40 includes a sheet-shaped current collector 41 and an active material layer 42. The current collector 41 may be made of a metal foil. The metal foil may be made of a conductive metal, such as aluminum or copper. The material of the current collector 41 may be appropriately selected depending on the polarity of the electrode 40. The metal foil may be replaced with a metal mesh or the like. The metal foil may have a structure in which a thin metal film is coated on both sides of a substrate made of an insulating film. An active material layer 42 is formed on at least one side of the current collector 41. The active material layer 42 is formed along the winding direction (X-axis). The electrode 40 includes a non-coated portion 43 at the end of the long side in the winding direction (X-axis). The non-coated portion 43 is a portion of the current collector 41 that is not coated with an active material. In the electrode 40, the region of the current collector 41 on which the active material layer 42 is formed may be referred to as the active material portion.

[0106] In electrode 40, the width of current collector 41 in the short side direction may be 60 mm to 70 mm, and the length of current collector 41 in the long side direction may be 3 m to 5 m. Therefore, the ratio of the short side to the long side of electrode 40 may be 1.2% to 2.3%. This ratio is significantly smaller than the 6% to 11% ratio of the long side to the short side of electrodes used in cylindrical batteries having 1865 or 2170 form factors.

[0107] Preferably, an insulating coating layer 44 may be formed at the boundary between the active material layer 42 and the uncoated portion 43. The insulating coating layer 44 is formed so that at least a portion thereof overlaps the boundary between the active material layer 42 and the uncoated portion 43. The insulating coating layer 44 prevents short-circuiting between two electrodes of opposite polarity that face each other via a separator. The insulating coating layer 44 may cover the boundary between the active material layer 42 and the uncoated portion 43 with a width of 0.3 mm to 5 mm. The insulating coating layer 44 includes a polymer resin and may also include an inorganic filler such as Al2O3 or SiO2. The portion of the current collector 41 covered by the insulating coating layer 44 is not a region coated with an active material layer and may therefore be considered an uncoated portion.

[0108] The uncoated portion 43 includes a first portion B1 adjacent to the core side, a second portion B3 adjacent to the outer periphery side, and a third portion B2 interposed between the first portion B1 and the second portion B3. The core and outer periphery refer to the central region and outer periphery of the electrode assembly when the electrode 40 is wound into the electrode assembly.

[0109] Of the first portion B1, the second portion B3, and the third portion B2, the third portion B2 has the longest length and accounts for most of the length of the electrode 40. The first portion B1 may form multiple winding turns adjacent to the core of the electrode assembly. The second portion B3 may form one or more winding turns adjacent to the outer periphery of the electrode assembly.

[0110] The third portion B2 includes a plurality of segments 45. Preferably, the segments 45 may be rectangular. Alternatively, the segments 45 may be trapezoidal, parallelogrammatic, semicircular, etc. The geometric shape of the segments 45 may be varied in various ways.

[0111] The plurality of segment segments 45 may be laser notched. Alternatively, the segment segments 45 may be formed by a known metal foil cutting process such as ultrasonic cutting or punching. In the winding direction (X-axis), the spacing (pitch) between the segment segments 45 may gradually increase from the core side toward the outer periphery.

[0112] A cutting groove 46 is interposed between adjacent segments 45 in the winding direction (X-axis). The cutting groove 46 is formed during the notching process of the segments 45. The cutting groove 46 includes a flat bottom portion 46a, a rounded portion 46b adjacent to the bottom portion 46a, and a side portion 46c of the segment 45. The rounded portion 46b relieves stress when the segment 45 is bent, thereby preventing cracks from occurring at the lower end of the segment 45.

[0113] To prevent damage to the active material layer 42 and / or the insulating coating layer 44 during bending of the cut pieces 45, it is preferable to provide a predetermined gap between the bottom 46a of the cut groove 46 and the active material layer 42. This is because stress is concentrated near the bottom 46a of the cut groove 46 when the cut pieces 45 are bent. The gap is preferably 0.2 mm to 4 mm, and more preferably 1.5 mm to 2.5 mm. Adjusting the gap within the above numerical range can prevent damage to the active material layer 42 and / or the insulating coating layer 44 near the bottom end of the cut groove 46 due to stress generated during bending of the cut pieces 45. In addition, the gap can prevent damage to the active material layer 42 and / or the insulating coating layer 44 due to tolerances during notching or cutting of the cut pieces 45. The bottom end of the cut groove 46 can be spaced 0.5 mm to 1.0 mm from the insulating coating layer 44. When the electrode 40 is wound, the end of the insulating coating layer 44 in the winding axis (Y-axis) direction may be located within a range of -2 mm to 2 mm in the winding axis direction from the end of the separator. The insulating coating layer 44 prevents short circuits between two electrodes of opposite polarity that face each other across the separator and supports the bending point when the divided piece 45 is bent. To improve the short circuit prevention effect between the two electrodes, the insulating coating layer 44 may be exposed to the outside of the separator. Furthermore, to further maximize the short circuit prevention effect between the two electrodes, the width of the insulating coating layer 44 may be increased so that the end of the insulating coating layer 44 in the winding axis (Y-axis) direction is located above the bottom 46a of the cutting groove 46. In one example, the end of the insulating coating layer 44 in the winding axis direction may be located within a range of -1 mm to +1 mm from the bottom 46a of the cutting groove 46.

[0114] Figure 5 is a top view of an electrode assembly JR manufactured by winding a positive electrode and a negative electrode having the structure of electrode 40 shown in Figure 4 together with a separator, Figure 6 is a partial perspective view showing the top of the electrode assembly JR, and Figure 7 is a partial cross-sectional view taken along line A-A' in Figure 5. The top of the electrode assembly JR shown in the drawings is the positive electrode side.

[0115] 4 to 7, the plurality of segment pieces 45 protrude outward from the separator in the winding axis direction (Y-axis). The plurality of segment pieces 45 are radially arranged with respect to the center of the core C of the electrode assembly JR to form a segment piece alignment portion 50. The segment piece alignment portion 50 refers to a collection of segment pieces 45 in which segment pieces 45 located on different winding turns are arranged while overlapping each other in the radial direction of the electrode assembly JR.

[0116] The radial overlap of the multiple segments 45 included in the segment alignment section 50 means that when a predetermined straight line is drawn from the center of the core through the segment alignment section 50, all of the segments 45 intersect with the line.

[0117] The segment alignment portion 50 has a structure extending a predetermined length along the radial direction of the electrode assembly JR, and in the segment alignment portion 50, the segment portions 45 of radially adjacent winding turns can overlap each other at their circumferential angles.

[0118] The number of segment alignment portions 50 may be four, three, or two, but is not limited to these. When there are multiple segment alignment portions 50, the segment alignment portions 50 may be arranged at equal or unequal intervals in the circumferential direction.

[0119] When there are four segment alignment portions 50, the angle between adjacent segment alignment portions 50 in the circumferential direction may be 80° to 100°, preferably 85° to 95°, and more preferably 90°. When there are three segment alignment portions 50, the angle between adjacent segment alignment portions 50 in the circumferential direction may be approximately 110° to 130°, preferably approximately 115° to 125°, and more preferably approximately 120°. When there are two segment alignment portions 50, the angle between adjacent segment alignment portions 50 in the circumferential direction may be approximately 170° to 190°, preferably approximately 175° to 185°, and more preferably approximately 180°.

[0120] The angle θ between adjacent segment alignment portions 50 in the circumferential direction is defined as the angle between the extension line of the side edge of one segment alignment portion 50 and the extension line of the side edge of the other segment alignment portion 50 that is closest to the segment alignment portion 50 when the electrode assembly JR is viewed from the winding axis direction (Y axis). The angle θ is substantially equal to the angle formed by an imaginary line (see the dashed dotted line) that is drawn from the center of the core C of the electrode assembly JR and passes through the center of the segment alignment portion 50 and is adjacent in the circumferential direction.

[0121] The pitch of the segment segments 45 gradually increases from the core side to the outer periphery in the winding direction (X-axis) of the electrode assembly JR, and can be determined according to a predetermined rule so that a segment segment alignment portion 50 is formed in the radial direction of the electrode assembly JR. The rule for changing the pitch of the segment segments 45 in the winding direction (X-axis) will be described later.

[0122] An electrolyte-impregnated portion 60 is formed between adjacent segment alignment portions 50 in the circumferential direction of the electrode assembly JR. The electrolyte-impregnated portion 60 is formed while the region of the uncoated portion 43 where the cutting grooves 46 are formed is being wound up.

[0123] As shown in FIG. 7, the electrolyte-impregnated portion 60 is a section primarily impregnated with the electrolyte EL and has a height lower than the segment alignment portion 50 in the winding axis direction (Y-axis). The electrolyte-impregnated portion 60 does not have segment pieces 45 protruding outward from the separator Se. Furthermore, in the electrolyte-impregnated portion 60, between adjacent separators Se in the radial direction of the electrode assembly JR, the end of the active material layer a1 of the positive electrode E1 and the end of the active material layer a2 of the negative electrode E2 are spaced a predetermined distance below the end of the separator Se. Therefore, insulation between the positive electrode E1 and the negative electrode E2 can be maintained. In an embodiment, the distance may be 0.6 mm to 1 mm. An insulating coating layer 44 may be formed on at least one of the end of the positive electrode E1 and the end of the negative electrode E2. The end of the positive electrode E1 may include a sliding portion where the thickness of the active material layer a1 gradually decreases. The electrode and separator arrangement structure shown in FIG. 7 may also be applied to the lower portion of the electrode assembly JR. Preferably, an insulating coating layer 44 and a sliding portion may be formed on the end of the negative electrode E2 at the bottom of the electrode assembly JR.

[0124] The electrolyte EL can be impregnated into the electrode assembly JR while passing through the gap between the ends of the separator Se and directly contacting the positive electrode E1 and the negative electrode E2. Specifically, the electrolyte EL dropped onto the electrode assembly JR quickly penetrates into the electrode assembly JR while simultaneously contacting the ends of the positive electrode E1 and the negative electrode E2 and the end of the separator Se. This significantly improves the electrolyte impregnation rate.

[0125] The width W of the segment 45 can be set to an appropriate value taking into consideration the size of the welding area of ​​the current collector plate and the impregnation rate of the electrolyte EL. Preferably, the width W of the segment 45 can be set in the range of 3 mm to 11 mm. If the width W of the segment 45 is smaller than 3 mm, the welding area of ​​the current collector plate is excessively reduced, reducing the processability of the welding process and increasing the possibility of failure in folding the tab during electrode operation. On the other hand, if the width W of the segment 45 is larger than 11 mm, the area of ​​the electrolyte-impregnated portion 60 is reduced, which reduces the impregnation rate of the electrolyte and increases the possibility of failure in the subsequent bending (forming) process of the segment 45.

[0126] Preferably, the height H of the segment 45 may be substantially uniform in the radial direction of the electrode assembly JR. For example, the height of the segment 45 may be 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. Alternatively, the height H of the segment 45 may increase stepwise from the core side to the outer periphery side of the electrode assembly JR. For example, the height of the segment 45 may increase stepwise from 2 mm to 10 mm. For example, when the core diameter of the electrode assembly JR is 8 mm, the height of the segment 45 may increase in 1 mm increments from 2 mm to 10 mm in the radius range of 6 mm to 14 mm. By increasing the height H of the segment 45 stepwise, the number of laminations of the segment 45 on the bent surface of the segment 45 can be increased, and the length of the region with a uniform number of laminations can be increased in the radial direction of the electrode assembly JR. This will be described later.

[0127] Referring to FIG. 4, the width d of the first portion B1 B1 The width d of the first portion B1 is designed so that the core of the electrode assembly is not blocked when the segment 45 of the third portion B2 that is closest to the first portion B1 is bent toward the core. B1 The third portion B2 can be designed so that when the divided piece 45 of the third portion B2 is bent toward the core, the core of the electrode assembly JR is opened outward by 90% or more in diameter.

[0128] Preferably, the height H of the segment 45 may increase from the core side toward the outer periphery depending on the radius of the winding turn on which the segment 45 is located and the radius of the core.

[0129] In one embodiment, the height H of the segment 45 increases from h1 to h2 with increasing radius of the winding turn. N If we increase the height stepwise over N stages until the k-th height of the section 45, h k (k is a natural number between 1 and N), height h k The starting radius of the winding turn containing the segment 45 is r k , the radius of the core is r c Then, the heights h1 to h5 of the segment 45 are determined so that the following formula 3 is satisfied. N can be determined.

[0130] [Formula 3] 2mm≦h k ≦r k -α*r c (Preferably, a is 0.90 to 1)

[0131] Height h of section 45 k If formula 3 is satisfied, even if the segment pieces 45 of the segment piece alignment portion 50 are bent toward the core, 90% or more of the diameter of the core can be opened to the outside.

[0132] For example, if the radius of the entire winding turn of the electrode assembly JR is 22 mm, the height of the sub-segment 45 starts at 3 mm, and as the radius of the winding turn including the sub-segment 45 increases by 1 mm, the height of the sub-segment 45 increases in order from 3 mm to 4 mm, 5 mm, and 6 mm, while the height of the remaining winding turns remains substantially constant at 6 mm. That is, the width of the height-variable section of the sub-segment 45 of the radius of the entire winding turn is 3 mm, and the remaining radius sections correspond to uniform height sections.

[0133] In this case, the radius r of the core of the electrode assembly c The starting radii r1, r2, r3, r4 of the winding turn including the segment 45 having heights of 3 mm, 4 mm, 5 mm, and 6 mm according to the above are as shown in Table 1 below when α is 1 and the equality condition is applied in the inequality on the right.

[0134] [Table 1]

[0135] When the segment 45 is positioned at the radial position shown in Table 1, the core is not blocked even when the segment 45 is bent toward the core. Meanwhile, r1, r2, r3, and r4 shown in Table 1 can be shifted toward the core depending on the α value. In one example, when α is 0.90, r1, r2, r3, and r4 can be shifted toward the core by 10% of the core radius. In this case, when the segment 45 is bent toward the core, 10% of the core radius is blocked by the segment 45. r1, r2, r3, and r4 shown in Table 1 are limit values ​​for the position where the segment 45 starts. Therefore, the position of the segment 45 can be shifted a predetermined distance toward the outer periphery from the radius shown in Table 1. Figure 8 shows the relationship between the heights h1, h2, h3, and h4 of the segment 45 and the core radius r c 10 is a diagram showing a schematic relationship between the radii r1, r2, r3, and r4 of the winding turns at which the winding segment 45 begins to appear.

[0136] Referring to Table 1 and FIG. 8, for example, the radius r of the core C c When the radius of the core C is 3 mm, the starting radii r1, r2, r3, and r4 of the winding turn including the fractional segments 45 with heights of 3 mm (h1), 4 mm (h2), 5 mm (h3), and 6 mm (h4) may be 6 mm, 7 mm, 8 mm, and 9 mm, respectively, and the height of the fractional segments 45 may be maintained at 6 mm from the radius of 9 mm to the last winding turn. Furthermore, the fractional segments 45 may not be included in winding turns with radii smaller than 6 mm (r1). In this example, the fractional segment 45 with a height of 3 mm (h1) closest to the core C is located from the winding turn with a radius of 6 mm. Therefore, even if the fractional segment 45 is bent toward the core C, it only covers the radius section from 3 mm to 6 mm and does not substantially block the core C. The position of the fractional segment 45 is determined by the value of α in Equation 1, depending on the core radius r. c can be shifted to the core C side within 10% of the

[0137] Width d of the first portion B1 B1may increase in proportion to the bending length of the third portion B2 segment 45 closest to the first portion B1. The bending length corresponds to the length from the bending point (47 in FIG. 7) to the top edge of the third portion B2 segment 45. Preferably, when the electrode 40 is used to manufacture an electrode assembly for a cylindrical battery with a form factor of 4680, the width d of the first portion B1 B1 can be set to 180 mm to 350 mm depending on the diameter of the core of the electrode assembly JR and the height of the division piece 45 of the third portion B2.

[0138] The folding points 47 of the segments 45 may be set on a line passing through the bottoms 46a of the cutting grooves 46 or at a point spaced a predetermined distance above that line. If the segments 45 are folded toward the core at a point spaced a predetermined distance from the bottom of the cutting grooves 46, overlapping of the segments in the radial direction becomes easier. When the segments 45 are folded, the outer segments press against the inner segments relative to the center of the core. If the folding points 47 are spaced a predetermined distance from the bottom of the cutting grooves 46, the inner segments are pressed against the outer segments in the winding axial direction, making overlapping of the segments 45 easier. The separation distance between the folding points 47 may be 3 mm or less, preferably 2 mm or less.

[0139] The pitch of the segments 45 corresponds to the width of the cut grooves 46 in the winding direction (X-axis), and can be predetermined so that segment alignment portions 50 are formed in a predetermined region in the radial direction of the electrode assembly JR when the electrode 40 is wound. The predetermined pitch information of the segments 45 can be referenced when notching the uncoated portion 43 of the electrode 40 using a notching device to form a plurality of segments 45.

[0140] When the electrode 40 is wound, a spiral winding turn structure is formed. As the number of winding turns increases, the radius of the electrode assembly JR increases slightly. Therefore, the spiral winding structure of the electrode 40 can be approximated to a structure of continuously connected semicircles whose radius increases uniformly every half winding turn. This approximated spiral winding turn structure can be used to predetermine the pitch of the segment 45. Hereinafter, a winding turn structure approximated by continuously connected semicircles will be referred to as an approximated winding turn structure.

[0141] FIG. 9a is a diagram showing a schematic diagram of an approximate winding turn structure in which semicircles C1, C2, C3, C4, C5, C6, ... whose radii increase every 1 / 2 winding turn are connected in series to determine the pitch of the winding segment 45.

[0142] Referring to FIG. 9a, the line of the approximate wound turn structure approximately corresponds to the line where a plane passing through the center position in the thickness direction of the current collector 41 included in the electrode 40 intersects with a plane perpendicular to the winding axis of the electrode assembly JR.

[0143] The approximate wound turn structure is a structure in which semicircles with radii increasing by Δ / 2 are connected in a counterclockwise direction. In other words, semicircles C1 (R1), C2 (R2), C3 (R3), C4 (R4), C5 (R5)... with radii increasing by Δ / 2 are connected in a counterclockwise direction to form the approximate wound turn structure. The symbols in parentheses indicate the radii. R2 is R1 + Δ / 2, R3 is R1 + Δ, R4 is R1 + 3Δ / 2, and R5 is R1 + 2Δ.

[0144] In the drawings, Δ corresponds to the distance between adjacent winding turns in the radial direction in the winding turn structure of the electrode assembly JR. Referring to Figure 7, one positive electrode E1, one negative electrode E2, and two separators Se are included between the winding turns that pass through the center in the thickness direction of current collectors (foils) e1 and e2. Therefore, Δ is the sum of the thicknesses of the positive electrode E1, negative electrode E2, and two separators Se. The thickness of the positive electrode E1 is the sum of the thicknesses of the current collector (foil) e1 and the active material layers a1 coated on both sides of it, and the thickness of the negative electrode E2 is the sum of the thicknesses of the current collector (foil) e2 and the active material layers a2 coated on both sides of it.

[0145] In FIG. 9a, the point where semicircle C1 having radius R1 intersects with the positive X-axis corresponds to the boundary between first portion B1 and third portion B2, i.e., the position where the first segment 45 appears based on the winding direction (X-axis). The winding turn structure formed by first portion B1 of electrode 40 is not shown in FIG. 9a. Semicircle C6 having radius R6 is indicated by a dotted line. This means that the connection of semicircles continues until the total length of the entire semicircle is equal to the total length of second portion B3 and third portion B2 of electrode 40. The radius of the semicircle increases in increments of "Δ / 2" as described above. C odd indicates the centers of odd-indexed semicircles C1, C3, C5, etc., and C even denotes the center of the even-indexed semicircles C2, C4, C6, etc. The center of the odd-indexed semicircles is C odd and the centers of the even-indexed semicircles are C even is the same as

[0146] 9b is a diagram for deriving a mathematical formula for determining the pitch of the segment 45 using the approximate wound turn structure shown in Fig. 9a. For convenience of explanation, an embodiment will be described in which the segment 45 is arranged in a cross shape as shown in Fig. 5, and the angle between adjacent segment alignment portions 50 in the circumferential direction is substantially 90°.

[0147] In FIG. 9b, the parameters indicated by the symbols are as follows: - A1: Length of the first piece in the winding direction (or length of the arc in the semicircle C1) -A2: Length of the second piece in the winding direction (or the arc length of the semicircle C1) -A3: Length of the third segment in the winding direction (or the arc length of the semicircle C2) -D1: The pitch between the first and second segments (or the arc length of the semicircle C1) -D2: the pitch between the second and third segments (or the length of the arc spanning semicircles C1 and C2) -θ A1 :The inscribed angle of the first intercept in the semicircle C1 that contains the arc corresponding to the first intercept -θ A2 :The inscribed angle of the second segment in the semicircle C1 containing the arc corresponding to the second segment -θ A3 :The inscribed angle of the third segment in the semicircle C2 containing the arc corresponding to the third segment -θ D1 : The inscribed angle of the first pitch D1 in the semicircle C1 that contains the arc corresponding to the first pitch D1 -θ D2 : The inscribed angle of the second pitch D2 in the semicircles C1 and C2 that contain the arc corresponding to the second pitch D2

[0148] When the segments 45 are arranged radially in a cross shape as shown in FIGS. 5 and 6, the angle of circumference θ of the first segment A1 and the inscribed angle θ of the first pitch D1 D1 The sum of the angle θ and the angle θ can be set to 90°. A1 and inscribed angle θ D1 Since is a generalized angle, the inscribed angle θ A1 and inscribed angle θ D1 The sum of these angles does not appear to be 90°. Similarly, the angle θ of the second segment A2 and the inscribed angle θ of the second pitch D2 D2The sum of these may be set to 90°. If the angle between adjacent segment alignment portions 50 in the circumferential direction is 120°, the 90° may be replaced with 120°. Also, if the angle between adjacent segment alignment portions 50 in the circumferential direction is 180°, the 90° may be replaced with 180°.

[0149] According to geometry, the inscribed angle of an arc is expressed as "length of the arc / radius." Also, if an arc is located between two connected semicircles, the inscribed angle of the arc can be approximated as "length of the arc / (average radius of the two semicircles)."

[0150] From the above description, the inclined angle θ A1 , θ A2 , θ D1 and θ D2 can be expressed as the following Equation 4.

[0151] [Formula 4] θ A1 =A1 / R1, θ D1 =D1 / R1 θ A2 =A2 / R1, θ D2 =D2 / {(R1+R2) / 2} θ A1 +θ D1 =π / 2, θ D1 =π / 2-θ A1 θ A2 +θ D2 =π / 2, θ D2 =π / 2-θ A2 Here, R2=R1+Δ / 2.

[0152] In Equation 4, π / 2 (90°) can be replaced with 2π / 3 (120°), π (180°), etc. depending on the angle between adjacent segment alignment portions 50 in the circumferential direction.

[0153] On the other hand, the length of the arc corresponding to the first pitch D1 is the circumference angle θ D1 and the radius R1 of the semicircle C1, the pitch D1 can be expressed as the following Equation 5.

[0154] [Formula 5] D1=θ D1 *R1=(π / 2-θ A1 )*R1=(π / 2-A1 / R1)*R1

[0155] Similarly, the length of the arc corresponding to the second pitch D2 is the inclined angle θ D2 and the average radius of the semicircles C1 and C2, the pitch D2 can be expressed as Equation 6 below.

[0156] [Formula 6] D2=θ D2 *(R1+R2) / 2=(π / 2-θ A2 )*{(R1+R2) / 2}=(π / 2-A2 / R1)*{(R1+R2) / 2}

[0157] In Equations 5 and 6, A1 and A2 correspond to the lengths of the first and second segments in the winding direction and are known values. Preferably, A1 and A2 are the same. Furthermore, R1 is a known value based on the design conditions of the electrode assembly, and R2 is a value determined by Δ.

[0158] Referring to the above description, the n+1th pitch D adjacent to the n+1th segment along the winding direction n+1 can be generalized and expressed as the following Equation 7.

[0159] [Formula 7] Case 1:D n+1 =θ Dn+1 *R n+1 =(90°-θ An+1 )*R n+1 Case 2:D n+1 =θ Dn+1 *(R n +R n+1 ) / 2=(90°-θ An+1 )*(R n +R n+1 ) / 2 (n is an integer greater than or equal to 0)

[0160] In Equation 7, the equation for Case 1 is the n+1th pitch D n+1 The arc corresponding to the first pitch D1 is similar to the arc corresponding to the n+1th semicircle C n+1 This is the formula that applies when the

[0161] On the other hand, the formula for Case 2 is the n+1th pitch D n+1 The arc corresponding to the second pitch D2 is similar to the arc corresponding to the nth semicircle C n and the n+1th semicircle C n+1 This is a formula that applies when the object is located across the

[0162] In the winding direction (X-axis), the lengths A1, A2, A3, etc. of the segments 45 and the radius R1 of the semicircle where the arc of the first segment is located are known values ​​based on design conditions, and Δ, a factor that determines the radius of the semicircle, is also a known value based on the electrode thickness and the separator thickness.

[0163] Therefore, the general formula D for the pitch of the known interval and the interval n+1 By using this method, the notching position of the segment 45 can be determined in the uncoated portion 43 of the electrode 40, and the segment 45 can be formed in an accurate position. Furthermore, by winding up the electrode with the segment 45 formed in this way as an electrode assembly, segment alignment portions 50 extending radially can be formed at the top and bottom of the electrode assembly.

[0164] Specifically, a portion corresponding to the first portion B1 is cut from the uncoated portion 43 of the electrode 40. Next, a section corresponding to the length A1 of the first segment is skipped from the point where cutting of the first portion B1 ends. A section of the uncoated portion 43 corresponding to the first pitch D1 is cut from the point where the cutting skip section ends. Next, a section corresponding to the length of the second segment is skipped, and a section of the uncoated portion 43 corresponding to the second pitch D2 is cut from the point where the cutting skip section ends. This process of cutting uncoated portions corresponding to the pitch of the segment segments and skipping cutting of uncoated portions where segment segments will be formed can be repeated until the notching process is completed for the entire uncoated portion. A jelly-roll-type electrode assembly can be manufactured using the positive and negative electrodes manufactured through this notching process, and a separator, to form segment alignment portions 50 extending radially from the top and bottom of the electrode assembly, as shown in FIG. 5.

[0165] The known values ​​used in the notching process of the minute segments and the pitch values ​​predetermined by the formulas may be recorded in a recording medium of a computer device. The notching device of the minute segments may be connected to the computer device via a network and / or a data line. The notching device of the minute segments may use the data A1, A2, A3, ..., A4 about the lengths of the minute segments in the winding direction recorded in the recording medium of the computer device. n and pitch data D1, D2, D3, ..., D n The information about the cutting edge can be read out and the operation and movement of the notching means (e.g., a laser cutter) can be controlled to form the cutting edge at the desired position.

[0166] Since notching devices for forming the divided pieces in the uncoated portion are well known in the art, a detailed description of the specific configuration of the notching device will be omitted.

[0167] On the other hand, in the winding direction (X axis), the length of each of the segments 45 does not necessarily have to be uniform, and may gradually increase from the core side toward the outer periphery. In this case, the lengths A1, A2, A3, ..., An etc. may be set to increase according to a certain rule. If the length of the segment 45 in the winding direction increases from the core side to the outer periphery, the shape of the segment alignment portion 50 may be deformed into a fan shape as shown in Figure 10a. Also, if the length of the segment 45 increases in the winding direction (X-axis), the segment 45 may not be bent smoothly when bent toward the core of the electrode assembly, and therefore, multiple sub-segments 45' may be formed in the uncoated section where one segment 45 is formed, as shown in Figure 9b.

[0168] Although not shown, it is obvious to a person skilled in the art to which the present invention pertains that the shape of the segment alignment section 50 can be modified into other geometric shapes such as a parallelogram, a trapezoid, etc. by adjusting the length and pitch of the segment 45 in the winding direction according to various conditions.

[0169] In one embodiment of the present invention, the segment 45 may be modified into various shapes while satisfying at least one of the following conditions. Condition 1: The width at the bottom is wider than the width at the top. Condition 2: The width of the bottom and the width of the top are equal. Condition 3: The width remains the same from bottom to top. Condition 4: The width decreases from bottom to top. Condition 5: The width decreases and then increases from bottom to top. Condition 6: The width increases and then decreases from bottom to top. Condition 7: The width increases from bottom to top and then remains constant. Condition 8: The width decreases from bottom to top and then remains constant. Condition 9: The interior angles on one side of the lower part are the same as the interior angles on the other side. Here, the interior angle may be defined as the angle formed by the side of the segment with respect to the width direction of the lower part of the segment. If the side is curved, the interior angle is defined as the angle between the tangent drawn at the lowest point of the curve and the width direction of the lower part of the segment. Condition 10: The interior angles on one side of the lower part are different from the interior angles on the other side. Condition 11: The interior angle on one side of the lower part and the interior angle on the other side of the lower part are each an acute angle, a right angle, or an obtuse angle. Condition 12: Symmetrical with respect to the winding axis direction. Condition 13: Asymmetrical with respect to the winding axis direction. Condition 14: The sides are straight. Condition 15: The side is curved. Condition 16: The sides are convex outward. Condition 17: The sides are convex inward. Condition 18: The upper and / or lower corners are constructed where two straight lines intersect. Condition 19: The upper and / or lower corners are structures where straight lines and curves intersect. Condition 20: The upper and / or lower corners are structures where curves intersect with each other. Condition 21: The top and / or bottom corners are rounded.

[0170] FIG. 11 is a diagram showing an example of the shape of a segment 45 according to a modified example of the present invention.

[0171] As shown in the drawings, the segment 45 may have various geometric shapes with the dotted line connecting the bottoms 46a of the cut grooves 46 on both sides as its base. The geometric shape has a structure in which at least one straight line, at least one curved line, or a combination thereof is connected. For example, the segment 45 may have a polygonal shape, a rounded shape, or various shapes that combine these.

[0172] Specifically, the segment 45 may be a symmetrical trapezoid (circle a); an asymmetrical trapezoid (circle b); a parallelogram (circle c); a triangle (circle l); a pentagon (circle k); an arc (circle e); or an ellipse (circle f).

[0173] The shape of the segment 45 is not limited to that shown in FIG. 11, and may be modified to other polygonal shapes, other round shapes, or a combination thereof, so long as it satisfies at least one of the above conditions 1 to 21.

[0174] In the polygonal shapes of the segments 45, circles a, b, c, k and l, the upper and / or lower corners may be straight line intersections or rounded (see enlargement of the upper and lower corners of circle a).

[0175] In the polygonal shapes a, b, c, k, and l of the segment 45 and the round shapes e and f of the segment 45, the interior angle θ1 on one side of the lower part and the interior angle θ2 on the other side can be the same or different, and the interior angle θ1 on one side of the lower part and the interior angle θ2 on the other side can be acute, right, or obtuse. The interior angle is the angle between the base and side of a geometric figure. When the side is curved, the straight line can be replaced by a tangent extending from the intersection of the base and side.

[0176] The shape of the side of the polygonal segment 45 can be varied in various ways.

[0177] As an example, the side of the segment circle a can be transformed into a curve that bulges outward, as in circle d, or into a curve that concaves inward, as in circle g or circle j.

[0178] As another example, the side of the segment with the circle a shape can be transformed into a concave folded line inward, like the shape of the circle h or circle i. Although not shown, the side of the segment with the circle a shape can be transformed into a bulging folded line outward.

[0179] In the shapes of the segments with variously modified sides, circle d, circle g, circle j, circle h, and circle i, the interior angle θ1 on one side of the lower part and the interior angle θ2 on the other side may be the same or different, and the interior angle θ1 on one side of the lower part and the interior angle θ2 on the other side may be an acute angle, a right angle, or an obtuse angle, respectively.

[0180] The width (length in the winding direction) of the segment 45 may have various change patterns from the bottom to the top.

[0181] As one example, the width of the minute segment 45 may be maintained constant from bottom to top (circle c). As another example, the width of the minute segment 45 may gradually decrease from bottom to top (circles a, b, d, e, f, and g). As yet another example, the width of the minute segment 45 may gradually decrease and then increase from bottom to top (circles i and j). As yet another example, the width of the minute segment 45 may gradually increase and then decrease from bottom to top (circle k). As yet another example, the width of the minute segment 45 may gradually decrease from bottom to top and then remain constant (circle h). Although not shown, the width of the minute segment 45 may gradually increase from bottom to top and then remain constant.

[0182] Meanwhile, among the shapes of the segment 45 illustrated in Fig. 11, the polygonal shape with a flattened top may be rotated 180°. As an example, when the shape of the segment a, b, d, or g is rotated 180°, the width of the segment 45 may gradually increase from the bottom to the top. As another example, when the shape of the segment h is rotated 180°, the width of the segment 45 may remain constant and then gradually increase from the bottom to the top.

[0183] In the above-described embodiment (variant), according to another aspect of the present invention, the shape of the segment 45 can be changed along the region of the third portion B2. For example, a round shape (e.g., semicircular, elliptical, etc.) that is advantageous for stress dispersion can be applied to the section where stress is concentrated, and a polygonal shape (e.g., quadrilateral, trapezoid, parallelogram, etc.) with the largest possible area can be applied to the section where stress is relatively low.

[0184] In the above-described embodiment (variant), the division structure of the third portion B2 may also be applied to the first portion B1. However, if the division structure is applied to the first portion B1, a reverse forming phenomenon may occur, in which the end of the first portion B1 bends toward the outer periphery when the division pieces 45 of the third portion B2 are bent due to the curvature radius of the core. Therefore, it is preferable not to apply a division structure to the first portion B1, or, even if a division structure is applied, to adjust the width, height, and / or spacing pitch of the division pieces 45 to a small level that does not cause reverse forming, taking into account the curvature radius of the core.

[0185] According to yet another aspect of the present invention, after the electrode 40 is wound into the electrode assembly JR, the segment pieces 45 that are exposed on the upper and lower sides of the electrode assembly JR and form the segment alignment portion 50 may overlap in multiple layers along the radial direction of the electrode assembly JR to form a folded surface region.

[0186] FIG. 12a is a schematic diagram showing a cross section of a folded surface region F formed by bending a segment 45 included in the segment alignment unit 50 toward the core C of the electrode assembly JR. The cross-sectional structure of the folded surface region F shows the structure when the segment alignment unit 50 is cut in the radial direction. The folded surface region F is formed by bending a segment 45 whose height gradually changes from the core side toward the outer periphery of the electrode assembly JR. In FIG. 12a, the cross section of the folded surface region F is shown only on the left side relative to the winding shaft of the electrode assembly JR. The folded surface region F can be formed on both the top and bottom of the electrode assembly JR.

[0187] Referring to FIG. 12a, the folded surface region F has a structure in which the split segments 45 are stacked in multiple layers in the winding axis direction. The stacking direction is the winding axis direction (Y axis). Section 1 is a split segment-free section (first portion) where there are no split segments, and sections 2 and 3 are sections where winding turns including the split segments 45 are located. Section 2 is a height-variable section where the height of the split segments 45 varies, and section 3 is a height-uniform section where the split segment height is maintained uniform up to the outer periphery of the electrode assembly. As will be described later, the radial lengths of sections 2 and 3 may vary. Meanwhile, the uncoated portion (second portion) included in at least one winding turn, including the outermost winding turn, may not include a split segment structure. In this case, the second portion may be excluded from section 3.

[0188] In the section 2, the height of the segment 45 is the radius r1 to r N The minimum height in the section is h1 (=h min ) to maximum height h N (=h max ) The height variable section where the height of the segment 45 changes is r1 to r N The radius r N From the radius R of the electrode assembly JR, the height of the segment 45 is h N The uniform height means that the deviation in height is within 5%.

[0189] At any radial position in the section 2 and the section 3, the number of layers of the segment 45 varies depending on the radial position. The number of layers of the segment 45 is determined by the width of the section 2, the minimum height h1 and the maximum height h2 of the segment 45 in the height variable section. N , and may vary depending on the height change width Δh of the segment 45. The number of stacked segments 45 is the number of segments that intersect with an imaginary line drawn from any radial position of the electrode assembly JR in the direction of the winding axis.

[0190] Preferably, the number of stacked segments 45 at each position of the folded surface area F can be optimized to match the required welding strength of the current collector plate by adjusting the height, width (length in the winding direction) and spacing pitch of the segment 45 according to the radius of the winding turn containing the segment 45.

[0191] First, when the minimum height h1 of the segment 45 is the same in the height variable section (circle 2), the maximum height h N How the number of stacked segments 45 changes along the radial direction of the folded surface region F depending on the change in the thickness of the folded surface region F will be described below with reference to a specific example.

[0192] Electrode assemblies of Examples 1-1 to 1-7 were prepared. The electrode assemblies of the Examples had a radius of 22 mm and a core diameter of 4 mm. The positive and negative electrodes included in the electrode assemblies had the electrode structure shown in FIG. 4. The second portion B3 of the positive and negative electrodes did not include the divided pieces. The length of the second portion B3 was 2% to 4% of the overall length of the electrode. The positive and negative electrodes and separator were wound using the method described with reference to FIG. 2. The winding turns ranged from 48 to 56 turns, with the winding turns being 51 turns in the Examples. The thicknesses of the positive, negative, and separator were 149 μm, 193 μm, and 13 μm, respectively. The thicknesses of the positive and negative electrodes included the thickness of the active material layer. The thicknesses of the positive and negative current collector plates were 15 μm and 10 μm, respectively. The lengths of the positive and negative electrodes in the winding direction were 3948 mm and 4045 mm, respectively.

[0193] In each example, the variable height section (circle 2) of the segment 45 was set to a minimum height of 3 mm so that it started from a radius of 5 mm. In each example, the height of the segment 45 was increased by 1 mm for every 1 mm increase in radius, and the maximum height of the segment 45 was varied from 4 mm to 10 mm.

[0194] Specifically, in Example 1-1, the height variable section (circle 2) of the minute segment 45 is 5 mm to 6 mm, and the height of the minute segment 45 varies from a radius of 3 mm to 4 mm. In Example 1-2, the height variable section (circle 2) of the minute segment 45 is 5 mm to 7 mm, and the height of the minute segment 45 varies from 3 mm to 5 mm. In Example 1-3, the height variable section (circle 2) of the minute segment 45 is 5 mm to 8 mm, and the height of the minute segment 45 varies from 3 mm to 6 mm. In Example 1-4, the height variable section (circle 2) of the minute segment 45 is 5 mm to 9 mm, and the height of the minute segment 45 varies from 3 mm to 7 mm. In Example 1-5, the height variable section (circle 2) of the minute segment 45 is 5 mm to 10 mm, and the height of the minute segment 45 varies from 3 mm to 8 mm. In Example 1-6, the height variable section (circle 2) of the segment 45 is 5 mm to 11 mm, and the height of the segment 45 varies from 3 mm to 9 mm. In Example 1-7, the height variable section (circle 2) of the segment 45 is 5 mm to 12 mm, and the height of the segment 45 varies from 3 mm to 10 mm. In Examples 1-1 to 1-7, the height of the segment 45 is uniform from the radius corresponding to the upper limit of the height variable section (circle 2) to the outer periphery. For example, in Example 1-7, the height of the segment 45 is uniform at 10 mm from a radius of 12 mm to 22 mm. In contrast, the electrode assembly of the comparative example maintained the height of the segment 45 at a uniform height of 3 mm from a radius of 5 mm to a radius of 22 mm.

[0195] FIG. 12b is a graph showing the results of counting the number of stacked segments along the radial direction in the folded surface region F of the positive electrode formed on the upper portion of the electrode assembly according to Examples 1-1 to 1-7 and the Comparative Example. The folded surface region F is formed by folding the segment 45 included in the segment alignment portion 50 toward the core of the electrode assembly JR. Substantially the same results are shown for the folded surface region of the negative electrode. The horizontal axis of the graph is the radius based on the center of the core, and the vertical axis of the graph is the number of stacked segments counted at each radius point. The same applies to FIGS. 12c and 12d described below.

[0196] Referring to FIG. 12b, the uniform number of layers section b1 of the divided section appears in common in Examples 1-1 to 1-7 and Comparative Example 1. The uniform number of layers section b1 is the radius section of the flat region in each graph. The length of the uniform number of layers section b1 increases as the maximum height of the divided section decreases, and the uniform number of layers section b1' of the comparative example is the longest. On the other hand, the number of layers of the divided section increases as the maximum height h of the divided section decreases. N In other words, the maximum height of the segment h N As the width of the variable height section (circle 2) of the electrode segment increases, the number of layers in the electrode segment increases, while the width of the uniform number of layers section b1 decreases. Outside the uniform number of layers section b1, a decreasing number of layers section b2 appears, in which the number of layers in the electrode segment decreases as the radius increases. The decreasing number of layers section b2 is a radial section in which the number of layers in the electrode segment decreases as the radius of the electrode assembly increases. The uniform number of layers section b1 and the decreasing number of layers section b2 are adjacent in the radial direction and are complementary to each other. In other words, as the length of one section increases, the length of the other section decreases. Furthermore, in the decreasing number of layers section b2, the decrease in the number of layers is proportional to the distance from the uniform number of layers section b1.

[0197] In terms of the number of stacked segments, Examples 1-1 to 1-7 have 10 or more stacked segments in the uniform segment number section b1. The region where the number of stacked segments is 10 or more can be set as a preferred welding target region. The welding target region is a region where at least a portion of the current collector plate is welded.

[0198] In Examples 1-1 to 1-7, the uniform number of layers section b1 starts at the radius point where the variable height section (circle 2) of the segment starts. That is, the variable height section (circle 2) starts at a radius of 5 mm and extends toward the outer periphery.

[0199] Table 2 below shows the results of calculating the ratio of the length of the segment-free section (c) to the radius (ba) of the electrode assembly excluding the core for the positive electrode in Examples 1-1 to 1-7 and Comparative Example 1; the ratio (e / f) of the length of the uniform number of stacks section b1 to the length (f) from the radius point (5 mm) where the uniform number of stacks section begins to the outermost point (22 mm) of the electrode assembly; the ratio (d / f) of the length of the variable height section (d) of the segment to the length (f) from the radius point (5 mm) where the uniform number of stacks section begins to the outermost point (22 mm) of the electrode assembly; the ratio (h) of the length of the electrode region corresponding to the segment-free section to the entire length of the electrode; the ratio (i) of the length of the electrode region corresponding to the variable height section to the entire length of the electrode; and the ratio (i) of the electrode region corresponding to the uniform height section to the entire length of the electrode.

[0200] The negative electrode has substantially the same parameters as the positive electrode, except for a difference of 0.1 to 1.2% in parameter h. The sum of the ratios h, i, and j is slightly different from 100%. This is because there is a section without a division segment in the second portion B3, which corresponds to the outer uncoated portion of the electrode. For example, in Example 1-1, there is no division segment in the second portion B3, which corresponds to approximately 3% of the total length of the electrode. In Table 2, a to f are parameters based on the radial length, and h, i, and j are parameters based on the length of the electrode in the winding direction. Furthermore, parameters corresponding to ratios (%) are values ​​rounded to the nearest tenth. These are substantially the same as in Tables 3 and 4 described below.

[0201] [Table 2]

[0202] With reference to Examples 1-1 to 1-7 in Table 2, the number of laminations of the segment segments ranged from 11 to 27, and the ratio (d / f) of the variable height section (d) to the radius section (f) containing the segment segments ranged from 6% to 41%. The ratio (e / f) of the uniform lamination number section (e) to the radius section (f) containing the segment segments ranged from 47% to 82%. The ratio (c / (ba)) of the segment-free section (c) to the radius (ba) of the electrode assembly excluding the core was 15%. The ratio of the length of the electrode region corresponding to the segment-free section to the overall length of the electrode was 6%, the ratio of the length of the electrode region corresponding to the variable height section to the overall length of the electrode was 3% to 32%, and the ratio of the length of the electrode region corresponding to the uniform height section to the overall length of the electrode was 59% to 87%. The number of laminations (g) of the uniform lamination number section was 10 or more in all of Examples 1-1 to 1-7. The uniform number of layers section (e) decreases as the height variable section (d) of the segment increases, but the number of layers (g) of the segment increases in the uniform number of layers section (e). Preferably, the uniform number of layers section (e) where the number of layers of the segment (g) is 10 or more can be set as the welding target area.

[0203] Cylindrical batteries with 1865 and 2170 form factors have an electrode assembly radius of approximately 9 mm to 10 mm. Therefore, in conventional cylindrical batteries, the radial length of the segment section (f) cannot be maintained at 17 mm, as in Examples 1-1 to 1-7, and the length of the uniform stack number section (e), where the number of segment stacks is 10 or more, cannot be maintained at 8 mm to 14 mm. This is because, in conventional cylindrical batteries, if the core radius is designed to be 2 mm, as in Examples 1-1 to 1-7, the radial section in which the segment can be arranged is essentially only 7 mm to 8 mm. Furthermore, in conventional cylindrical batteries, the length of the electrode in the winding direction is approximately 600 mm to 980 mm. This short electrode length is only approximately 15% to 24% of the length of the electrodes used in Examples 1-1 to 1-7 (positive electrode: 3948 mm, negative electrode: 4045 mm). Therefore, the numerical ranges for the parameters h, i, and j cannot be easily derived from the design specifications of conventional cylindrical batteries.

[0204] Next, in the variable height section of the section (circle 2 in Figure 12a), the maximum height of the section h N When the minimum height h1 of the segment pieces is the same, how the number of stacked segment pieces changes along the radial direction of the folded surface area F when the minimum height h1 of the segment pieces is changed will be described using a specific example.

[0205] The electrode assemblies of Examples 2-1 to 2-5 have a radius of 22 mm and a diameter of the core C of 4 mm. The minimum height h1 of the height variable section of the segment 45 (circle 2 in FIG. 12a) is 4 mm, and the maximum height h N was varied in 1 mm increments from 6 mm to 10 mm. Therefore, in the electrode assemblies of Examples 2-1 to 2-5, the widths of the section with variable segment height (circled 2 in FIG. 12a) were 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm, respectively, and the section without segment (circled 1 in FIG. 12a) was a radius section with a radius of 2 mm to 6 mm.

[0206] The electrode assemblies of Examples 3-1 to 3-4 have a radius of 22 mm and a diameter of the core C of 4 mm. The minimum height h1 of the height variable section of the segment 45 (circle 2 in FIG. 12a) is 5 mm, and the maximum height h N was varied in 1 mm increments from 7 mm to 10 mm. Therefore, in the electrode assemblies of Examples 3-1 to 3-4, the widths of the section with variable segment height (circled 2 in FIG. 12a) were 2 mm, 3 mm, 4 mm, and 5 mm, respectively, and the section without segment (circled 1 in FIG. 12a) was a radius section with a radius of 2 mm to 7 mm.

[0207] The electrode assemblies of Examples 4-1 to 4-3 have a radius of 22 mm and a diameter of the core C of 4 mm. The minimum height h1 of the height variable section of the segment 45 (circle 2 in FIG. 12a) is 6 mm, and the maximum height h N was varied in 1 mm increments from 8 mm to 10 mm. Therefore, in the electrode assemblies of Examples 4-1 to 4-3, the widths of the section with variable segment height (circled 2 in FIG. 12a) were 2 mm, 3 mm, and 4 mm, respectively, and the section without segment (circled 1 in FIG. 12a) was a radius section ranging from 2 mm to 8 mm.

[0208] The electrode assemblies of Examples 5-1 and 5-2 have a radius of 22 mm and a diameter of the core C of 4 mm. The minimum height h1 of the height variable section of the segment 45 (circle 2 in FIG. 12a) is 7 mm, and the maximum height h N was varied in 1 mm increments from 9 mm to 10 mm. Therefore, in the electrode assemblies of Examples 5-1 and 5-2, the widths of the section with variable segment height (circled 2 in FIG. 12a) were 2 mm and 3 mm, respectively, and the section without segment (circled 1 in FIG. 12a) was a radius section ranging from 2 mm to 9 mm.

[0209] 12c is a graph showing the results of counting the number of stacked sections measured along the radial direction in the folded surface region F of the positive electrode formed on the upper part of the electrode assemblies according to Examples 2-1 to 2-5, 3-1 to 3-4, 4-1 to 4-3, 5-1, and 5-2. Substantially the same results are shown for the folded surface region of the negative electrode.

[0210] In Figure 12c, graph (a) shows the results of counting the number of stacked pieces along the radial direction in the folded surface region F for Examples 2-1 to 2-5, graph (b) shows the results of counting the number of stacked pieces along the radial direction in the folded surface region F for Examples 3-1 to 3-4, graph (c) shows the results of counting the number of stacked pieces along the radial direction in the folded surface region F for Examples 4-1 to 4-3, and graph (d) shows the results of counting the number of stacked pieces along the radial direction in the folded surface region F for Examples 5-1 and 5-2.

[0211] Referring to FIG. 12c, the uniform number of layers section b1 of the sub-segment appears in all examples. The uniform number of layers section b1 is a radius section of a flat area in the graph. The length of the uniform number of layers section b1 is determined by the maximum height h1 of the sub-segment when the minimum height h1 of the sub-segment is the same. N The length of the uniform stacking section b1 is the maximum height h of the N When the number of layers is the same, the number of layers of the sub-segment increases as the minimum height h1 of the sub-segment decreases. N In the example, a section b2 with a decreased number of layers appears adjacent to a section b1 with a uniform number of layers.

[0212] In the embodiment, the number of layers of the segmented pieces in the uniform layer number section b1 is all equal to or greater than 10. Preferably, the region where the number of layers of the segmented pieces is equal to or greater than 10 can be set as a preferred welding target region.

[0213] In the examples, the uniform number of layers section b1 begins at the radial point where the variable height section of the segment (circled 2 in FIG. 12a) begins. In examples 2-1 to 2-5, the variable height section of the segment (circled 2 in FIG. 12a) begins at 6 mm and extends toward the outer periphery. In examples 3-1 to 3-4, the variable height section of the segment (circled 2 in FIG. 12a) begins at 7 mm and extends toward the outer periphery. In examples 4-3 to 4-3, the variable height section of the segment (circled 2 in FIG. 12a) begins at 8 mm and extends toward the outer periphery. In examples 5-1 and 5-2, the variable height section of the segment (circled 2 in FIG. 12a) begins at 9 mm and extends toward the outer periphery.

[0214] Table 3 below shows the results of calculating various parameters for Examples 2-1 to 2-5, Examples 3-1 to 3-4, Examples 4-1 to 4-3, Examples 5-1 and 5-2, including the ratio (e / f) of the length of the uniform stack count section to the length from the radius point (6 mm, 7 mm, 8 mm, 9 mm) where the uniform stack count section begins to the outermost point (22 mm) of the electrode assembly, and the ratio (d / f) of the length of the variable height section (circle 2) of the segment to the length from the radius point (6 mm, 7 mm, 8 mm, 9 mm) where the uniform stack count section begins to the outermost point (22 mm) of the electrode assembly.

[0215] [Table 3]

[0216] Referring to Examples 2-5, 3-4, 4-3, and 5-2 in Table 3 along with FIGS. 12a and 12c, the maximum height h of the segment in the height variable section (circle 2) of the segment is NAlthough the thickness is the same at 10 mm, the minimum height h1 of the segment increases by 1 mm from 4 mm, 5 mm, 6 mm, and 7 mm, and the length of the height variable section (circle 2) decreases by 1 mm from 6 mm, 5 mm, 4 mm, and 3 mm. In the four examples, the ratio (e / f) of the uniform number of layers section is the highest in Example 2-5 at 69% and the lowest in Example 5-1 at 31%, and the number of layers in the uniform number of layers section is all the same. From the results shown in Table 3, the maximum height h1 of the segment segment N When the minimum length h1 of the sub-segment is the same, the width of the uniform number of layers section increases proportionally as the minimum height h1 of the sub-segment decreases and the width of the variable height section (circle 2) of the sub-segment increases. This is because the smaller the minimum length h1 of the sub-segment, the closer the radius point where the sub-segment starts to the core side, and the area where the sub-segments are stacked expands toward the core side.

[0217] Referring to Table 3, the number of laminations of the segment is 16 to 27, the ratio (d / f) of the segment height variable section (circle 2) is 13% to 38%, and the ratio (e / f) of the uniform lamination section is 31% to 69%. The ratio (c / (ba)) of the segment-free section (c) to the radius (ba) of the electrode assembly excluding the core is 20% to 35%. The ratio of the length of the electrode region corresponding to the segment-free section to the overall length of the electrode is 10% to 20%, the ratio of the length of the electrode region corresponding to the height variable section to the overall length of the electrode is 6% to 25%, and the ratio of the length of the electrode region corresponding to the uniform height section to the overall length of the electrode is 62% to 81%.

[0218] Cylindrical batteries with 1865 and 2170 form factors have an electrode assembly radius of approximately 9 mm to 10 mm. Therefore, unlike the embodiment, the radial length of the segment section (f) cannot be set to 13 mm to 16 mm. The length of the segment-free section (c) cannot be set to 4 mm to 7 mm, while the length of the uniform-number section (e) with 10 or more segment stacks cannot be set to 5 mm to 11 mm. This is because, in a conventional cylindrical battery, if the core radius is designed to be 2 mm as in the embodiment, the radial section in which the segment can be arranged is essentially only 7 mm to 8 mm. Furthermore, in a conventional cylindrical battery, the length of the electrode in the winding direction is approximately 600 mm to 980 mm. This short electrode length is only approximately 15% to 24% of the electrode length in the embodiment (3948 mm for the positive electrode and 4045 mm for the negative electrode). Therefore, the numerical ranges for the parameters h, i, and j cannot be easily derived from the design specifications of a conventional cylindrical battery.

[0219] Next, the minimum height h1 and maximum height h2 of the section are set in the variable height section of the section (circle 2 in Figure 12a). N When the diameter of the core C of the electrode assembly is the same, how the number of laminations of the segmented pieces changes along the radial direction of the folded surface area F will be explained using a specific example.

[0220] The electrode assemblies of Examples 6-1 to 6-6 have a radius of 22 mm, and the radius of the core C is 4 mm. The minimum height h1 of the segment 45 in the height variable section (circle 2 in FIG. 12a) is 3 mm, and the maximum height h N was varied in 1 mm increments from 5 mm to 10 mm. Therefore, in the electrode assemblies of Examples 6-1 to 6-6, the widths of the section with variable segment height (circled 2 in FIG. 12a) were 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm, respectively, and the section without segment (circled 1 in FIG. 12a) was a radius section with a radius of 4 mm to 7 mm.

[0221] The electrode assemblies of Examples 7-1 to 7-6 have a radius of 22 mm, and the radius of the core C is 2 mm. The minimum height h1 of the segment 45 in the height variable section (circle 2 in FIG. 12a) is 3 mm, and the maximum height h N was varied in 1 mm increments from 5 mm to 10 mm. Therefore, in the electrode assemblies of Examples 7-1 to 7-6, the widths of the height-variable section of the segment (circled 2 in FIG. 12a) were 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm, respectively, and the segment-free section (circled 1) was the same as the radius section from 2 mm to 5 mm.

[0222] 12d is a graph showing the results of counting the number of stacked sections measured along the radial direction in the folded surface region F of the positive electrode formed on the upper part of the electrode assemblies according to Examples 6-1 to 6-6 and 7-1 to 7-6. Substantially the same results are observed in the folded surface region of the negative electrode.

[0223] In FIG. 12d, graph (a) shows the results of counting the number of stacked sections measured along the radial direction in the folded surface region F for Examples 6-1 to 6-6, and graph (b) shows the results of counting the number of stacked sections measured along the radial direction in the folded surface region F for Examples 7-1 to 7-6.

[0224] Referring to FIG. 12d, the uniform number of layers section b1 of the segment appears in all examples. The uniform number of layers section b1 is a radial section of a flat area in the graph. The radial length of the uniform number of layers section b1 is the same as the maximum height h1 of the segment when the minimum height h1 of the segment is the same. N On the other hand, in the uniform stacking section b1, the number of stacks of the sub-section increases as the maximum height h N In the example, a section b2 with a reduced number of layers is observed adjacent to the section b1 with a uniform number of layers.

[0225] In the embodiment, the number of layers of the segmented pieces in the uniform layer number section b1 is all equal to or greater than 10. Preferably, the region where the number of layers of the segmented pieces is equal to or greater than 10 can be set as a preferred welding target region.

[0226] In the examples, the uniform number of layers section b1 begins at the radius where the variable height section of the segment (circled 2 in FIG. 12a) begins. In Examples 6-1 to 6-6, the radius where the variable height section of the segment (circled 2 in FIG. 12a) begins is 7 mm, and in Examples 7-1 to 7-6, the radius where the variable height section of the segment (circled 2 in FIG. 12a) begins is 5 mm.

[0227] Table 4 below shows the calculation results of various parameters for Examples 6-1 to 6-6 and Examples 7-1 to 7-6, including the ratio (e / f) of the length of the uniform stack count section to the length from the radius point (7 mm, 5 mm) where the uniform stack count section begins to the outermost point (22 mm) of the electrode assembly, and the ratio (d / f) of the length of the variable height section (circle 2) of the segment to the length from the radius point (7 mm, 5 mm) where the uniform stack count section begins to the outermost point (22 mm) of the electrode assembly.

[0228] [Table 4]

[0229] Referring to FIG. 12a and Examples 6-6 and 7-6 in Table 4, the minimum height h1 and maximum height h2 of the segment in the height variable section (circle 2) of the segment are Nare the same, at 3 mm and 10 mm, respectively. However, Example 6-6 has a core radius 2 mm larger than Example 7-6. Therefore, Example 6-6 has a uniform lamination count section (e) and a segment section (f) 2 mm smaller than Example 7-6, but the number of laminations in the segment in the uniform lamination count section is the same. This result is due to the difference in core radius. From the results shown in Table 4, it can be seen that when the width of the variable height section (circle 2) of the segment is the same, as the core radius (a) becomes smaller, the ratio (d / f) of the variable height section (circle 2) decreases while the ratio (e / f) of the uniform lamination count section increases. Referring to Table 4, it can be seen that the number of laminations in the segment ranges from 13 to 27, the ratio (d / f) of the variable height section (circle 2) of the segment ranges from 12% to 47%, and the ratio (e / f) of the length of the uniform lamination count section ranges from 40% to 76%. The ratio (c / (ba)) of the segment-free section (c) to the radius (ba) of the electrode assembly excluding the core is 15% to 17%. The ratio of the length of the electrode region corresponding to the segment-free section to the entire length of the electrode is 6%, the ratio of the length of the electrode region corresponding to the height-variable section to the entire length of the electrode is 7% to 32%, and the ratio of the length of the electrode region corresponding to the uniform height section to the entire length of the electrode is 59% to 83%.

[0230] Cylindrical batteries with 1865 and 2170 form factors have an electrode assembly radius of approximately 9 mm to 10 mm. Therefore, unlike the embodiment, the radial length of the segment section (f) cannot be secured at 15 mm to 17 mm. It is also impossible to secure a length of approximately 3 mm for the segment-free section (c) while simultaneously securing a length of 6 mm to 13 mm for the uniform-number section (e) with 10 or more segment stacks. This is because, in conventional cylindrical batteries, if the core radius is designed to be 2 mm to 4 mm as in the embodiment, the radius section in which segment sections can be arranged is essentially only 5 mm to 8 mm. Furthermore, in conventional cylindrical batteries, the electrode winding length is approximately 600 mm to 980 mm. This short electrode length is only approximately 15% to 24% of the electrode length in the embodiment (3948 mm for the positive electrode and 4045 mm for the negative electrode). Therefore, the numerical ranges for the parameters h, i, and j cannot be easily derived from the design specifications of conventional cylindrical batteries.

[0231] Considering the data in Tables 2 to 4 comprehensively, the number of layered segments in the uniform layered segment section may be 11 to 27. The ratio (d / f) of the variable layered segment section (circled 2) may be 6% to 47%. The ratio (e / f) of the uniform layered segment section may be 31% to 82%. The ratio (c / (ba)) of the length of the layered segment-free section to the radius of the electrode assembly excluding the core may be 15% to 35%. The ratio of the length of the electrode region corresponding to the layered segment-free section to the overall length of the electrode (length in the winding direction) may be 6% to 20%. The ratio of the length of the electrode region corresponding to the variable layered segment section to the overall length of the electrode may be 3% to 32%. The ratio of the length of the electrode region corresponding to the uniform layered segment section to the overall length of the electrode may be 59% to 87%.

[0232] Meanwhile, the parameters described in Tables 2 to 4 are the radius of the core (a); the radius of the electrode assembly (b); the minimum height h1 and the maximum height h2 in the height variable section of the section. N The change in height of the segment per 1 mm increase in radius, Δh, can vary depending on design factors including the thickness of the positive electrode, negative electrode, and separator.

[0233] Therefore, the number of layered segments in the uniform layered segment section can be expanded to 10 to 35. The ratio (d / f) of the variable layered segment section (circled 1) can be expanded to 1% to 50%. The ratio (e / f) of the uniform layered segment section can be expanded to 30% to 85%. The ratio (c / (ba)) of the length of the layered segment-free section to the radius of the electrode assembly excluding the core can be expanded to 10% to 40%. The ratio of the length of the electrode region corresponding to the layered segment-free section to the overall length of the electrode (length in the winding direction) can be expanded to 1% to 30%. The ratio of the length of the electrode region corresponding to the variable layered segment section to the overall length of the electrode can be expanded to 1% to 40%. The ratio of the length of the electrode region corresponding to the uniform layered segment section to the overall length of the electrode can be expanded to 50% to 90%.

[0234] In the folded surface regions F formed on the upper and lower parts of the electrode assembly, the lamination number uniform sections can be used as welding target regions for the current collector plates.

[0235] Preferably, the welding area of ​​the current collector plate overlaps the uniform lamination number section by at least 50% in the radial direction of the electrode assembly, and the higher the overlap ratio, the more preferable.

[0236] Preferably, the other region of the welding region of the current collector plate that does not overlap with the uniform lamination number section can overlap with the reduced lamination number section adjacent to the uniform lamination number section in the radial direction.

[0237] More preferably, other regions of the welding region of the current collector plate that do not overlap with the uniform lamination number section can overlap with regions of the reduced lamination number section where the overlap number of divided segments is 10 or more.

[0238] Welding the current collector plate to the region where the number of laminated segments is 10 or more is preferable in terms of weld strength and in terms of preventing damage to the separator and active material layer during welding, and is particularly useful when welding the current collector plate using a high-power laser with high transmission characteristics.

[0239] When a uniform lamination section, in which 10 or more division pieces are stacked, is welded to a current collector plate using a laser, even if the laser output is increased to improve welding quality, the uniform lamination section absorbs most of the laser energy to form a weld bead, preventing damage to the separator and active material layer below the folded surface region F by the laser.

[0240] In addition, the area irradiated with the laser has 10 or more stacked pieces, so the weld beads are formed with sufficient volume and thickness, ensuring sufficient weld strength and reducing the resistance of the weld interface to a level suitable for fast charging.

[0241] The laser power used to weld the current collector plate can be determined by the desired weld strength between the folded surface area F and the current collector plate. The weld strength increases in proportion to the number of laminated segments. This is because the greater the number of laminated segments, the larger the volume of the weld bead formed by the laser. The weld bead is formed as the current collector plate material and the laminated segment material are melted together. Therefore, a larger volume of the weld bead results in a stronger bond between the current collector plate and the folded surface area, lowering the contact resistance at the weld interface.

[0242] Preferably, the welding strength is 2 kgf / cm 2 More than 4kgf / cm 2 The welding strength is preferably 8 kgf / cm or more. 2 Less than 6kgf / cm, preferably 6kgf / cm 2 It can be set to:

[0243] When the weld strength satisfies the above numerical range, the physical properties of the weld interface do not deteriorate even when the electrode assembly is subjected to severe vibrations in the winding axial direction and / or radial direction, and the resistance of the weld interface can also be reduced due to the sufficient volume of the weld beads.

[0244] The laser output required to meet the welding strength requirements varies depending on the laser device, but can be appropriately adjusted within the range of 250W to 320W or within the range of 40% to 90% of the maximum laser output specification provided by the device.

[0245] The weld strength is the tensile force per unit area of ​​the current collector (kgf / cm) when the current collector begins to separate from the folded surface area F. 2 ) can be defined as the weld strength. Specifically, after welding of the current collector plate is completed, a tensile force is applied to the current collector plate and the magnitude of the force is gradually increased. When the tensile force exceeds a critical value, the pieces begin to separate from the weld interface. At this time, the tensile force applied to the current collector plate divided by the area of ​​the current collector plate corresponds to the weld strength.

[0246] The folded surface region F is formed by stacking a plurality of layers of segment pieces, and according to the above-described embodiment, the number of stacked segment pieces can be increased from a minimum of 10 to a maximum of 35.

[0247] The thickness of the positive electrode current collector can be selected from the range of 10 μm to 25 μm, and the thickness of the negative electrode current collector can be selected from the range of 5 μm to 20 μm. Therefore, the folded surface region F of the positive electrode can include a region where the total laminate thickness of the divided pieces is 100 μm to 875 μm. Also, the folded surface region F of the negative electrode can include a region where the total laminate thickness of the divided pieces is 50 μm to 700 μm.

[0248] FIG. 12e is a top view of an electrode assembly showing a uniform lamination number section b1 and a reduced lamination number section b2 in the bent surface region F of the divided piece 45 according to an embodiment of the present invention.

[0249] 12e, the bent surface region F of the segment 45 is formed by bending the segment 45 included in the segment alignment portion 50 toward the core C of the electrode assembly JR. In FIG. 12e, the region between the two circles indicated by the dashed dotted lines corresponds to a uniform layer count section b1 where the number of layers of the segment 45 is 10 or more, and the region outside the uniform layer count section b1 corresponds to a reduced layer count section b2.

[0250] As an example, current collector plate P cis welded to the folded surface area F formed by the segment alignment portion 50, the current collector plate P c Welding pattern W on the surface p is generated. Welding pattern W p can be an array of line patterns or dot patterns. p corresponds to the welding area and can overlap with the uniform number of layers section b1 of the divided section along the radial direction by 50% or more. Therefore, the welding pattern W p A part of the layer count uniformity section b1 is included, and the remaining welding pattern W p can be included in the layer number decreasing section b2 outside the layer number uniform section b1. p The entire section may overlap with the uniform stack number section b1.

[0251] Preferably, the current collector plate P c The end of the portion in contact with the folded surface area F may cover the end of the portion 45 bent toward the core C in the last winding turn. In this case, the portion 45 is bent toward the current collector P. c The welding pattern W is pressed by p is formed, the current collector plate P c and the folded surface region F are strongly bonded. As a result, the split pieces 45 stacked in the winding axial direction are tightly adhered to each other, which reduces the resistance at the welding interface and prevents the split pieces 45 from lifting up.

[0252] Meanwhile, the bending direction of the split pieces may be opposite to the above-described direction. That is, the split pieces may be bent from the core side toward the outer periphery. In this case, the pattern in which the height of the split pieces changes along the winding direction (X-axis) may be opposite to that of the above-described embodiment (variant). For example, the height of the split pieces may decrease stepwise from the core side toward the outer periphery. Furthermore, the structure applied to the first portion B1 and the structure applied to the second portion B3 may be interchangeable. Preferably, the height of the split pieces may decrease stepwise from the core side toward the outer periphery, and the split piece height change pattern may be designed so that when the split piece closest to the outer periphery of the electrode assembly is bent toward the outer periphery, the end of the split piece does not protrude outside the outer periphery of the electrode assembly.

[0253] The electrode structure of the above-described embodiment (variant) may be applied to at least one of the first electrode and the second electrode having different polarities included in a jelly roll-type electrode assembly. Furthermore, when the electrode structure of the embodiment (variant) is applied to one of the first electrode and the second electrode, a conventional electrode structure may be applied to the other. Furthermore, the electrode structures applied to the first electrode and the second electrode may not be the same, but may be different.

[0254] As an example, when the first electrode and the second negative electrode are a positive electrode and a negative electrode, respectively, any one of the embodiments (variants) may be applied to the first electrode, and a conventional electrode structure (see FIG. 1) may be applied to the second electrode.

[0255] As another example, when the first electrode and the second electrode are a positive electrode and a negative electrode, respectively, any one of the embodiments (variants) may be selectively applied to the first electrode, and any one of the embodiments (variants) may be selectively applied to the second electrode.

[0256] In one embodiment of the present invention, the positive electrode active material coated on the positive electrode and the negative electrode active material coated on the negative electrode may be any active material known in the art without limitation.

[0257] As an example, the positive electrode active material has the general chemical formula A[A x M y ]O 2+z (A includes at least one element of Li, Na, and K; M includes at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru, and Cr; x≧0, 1≦x+y≦2, −0.1≦z≦2; and the stoichiometric coefficients x, y, and z are selected to maintain electroneutrality of the compound).

[0258] As another example, the positive electrode active material may be an alkali metal compound xLiM disclosed in U.S. Pat. No. 6,677,082, U.S. Pat. No. 6,680,143, etc. 1 O2-(1-x)Li2M 2O3(M 1 contains at least one element having an average oxidation state of 3; M 2 contains at least one element having an average oxidation state of 4; 0 ≦ x ≦ 1) can be.

[0259] As another example, the positive electrode active material has the general chemical formula Li a M 1 x Fe 1-x M 2 y P 1-y M 3 z O 4-z (M 1 contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg and Al; M 2 contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V and S; M 3 contains a halogen group element selectively containing F; 0 < a ≦ 2, 0 ≦ x ≦ 1, 0 ≦ y < 1, 0 ≦ z < 1; the stoichiometric coefficients a, x, y and z are selected so that the compound maintains electrical neutrality), or Li3M2(PO4)3 [M contains at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg and Al] can be a lithium metal phosphate represented by.

[0260] Preferably, the positive electrode active material may contain primary particles and / or secondary particles aggregated from primary particles.

[0261] As an example, as the negative electrode active material, a carbon material, a lithium metal or a lithium metal compound, silicon or a silicon compound, tin or a tin compound, etc. can be used. Metal oxides such as TiO2 and SnO2 having a potential of less than 2V can also be used as the negative electrode active material. As the carbon material, both low-crystalline carbon and high-crystalline carbon can be used.

[0262] The separator may be a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., either alone or in a laminate. Alternatively, the separator may be a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc.

[0263] At least one surface of the separator may include a coating layer of inorganic particles. Alternatively, the separator itself may be made of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are bound with a binder so that there is interstitial volume between adjacent particles.

[0264] The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. Non-limiting examples of the inorganic particles include Pb(Zr,Ti)O3 (PZT), Pb 1-x La x ZR 1-y Ti y O3(PLZT), PB(Mg3Nb 2 / 3 )O3-PbTiO3 (PMN-PT), BaTiO3, hafnia (HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO, and Y2O3.

[0265] Hereinafter, the structure of an electrode assembly according to an embodiment of the present invention will be described in detail.

[0266] FIG. 13 is a cross-sectional view of a jelly roll-type electrode assembly 100 in which the electrode 40 of the embodiment is applied to the first electrode (positive electrode) and the second electrode (negative electrode), cut along the Y-axis direction (winding axis direction) so as to pass through the segment alignment section 50.

[0267] Referring to FIG. 13, the uncoated portion 43a of the first electrode includes a first portion B1 adjacent to the core of the electrode assembly 100, a second portion B3 adjacent to the outer peripheral surface of the electrode assembly 100, and a third portion B2 interposed between the first portion B1 and the second portion B3.

[0268] The height of the uncoated portion of the first portion B1 is relatively smaller than the height of the divisional segments 45. In addition, in the third portion B2, the bending length of the innermost divisional segment 45 is equal to or shorter than the radial length R of the first portion B1. The bending length H corresponds to the distance from the point where the innermost divisional segment 45 is bent to the upper end of the divisional segment 45. In a modified example, the bending length H may be smaller than the sum of the radial length R of the winding turn formed by the first portion B1 and 10% of the radius of the core 102.

[0269] Therefore, even if the segment pieces 45 included in the segment piece alignment unit 50 are bent, 90% or more of the diameter of the core 102 of the electrode assembly 100 remains open to the outside. The core 102 is a cavity in the center of the electrode assembly 100. If the core 102 is not blocked, the electrolyte injection process can be performed without any problems, improving the efficiency of the electrolyte injection. In addition, a welding jig can be inserted through the core 102 to easily perform the welding process between the negative (or positive) electrode current collector plate and the battery housing (or rivet terminal).

[0270] The height of the uncoated portion of the second portion B3 is relatively lower than the height of the dividing piece 45. Therefore, when the beading portion of the battery housing is pressed near the wound turn of the second portion B3, it is possible to prevent the beading portion from coming into contact with the upper periphery of the electrode assembly 100, which could cause an internal short circuit.

[0271] In one variation, the second portion B3 may include a segment 45 that forms the segment alignment portion 50, and the height of the segment 45 of the second portion B3 may decrease gradually or in steps, unlike the illustration in FIG. 13. Also, in FIG. 13, the height of the segment 45 of the segment alignment portion 50 is uniform along a portion of the outer periphery, but the height of the segment 45 of the segment alignment portion 50 may increase gradually or in steps from the boundary between the first portion B1 and the third portion B2 to the boundary between the third portion B2 and the second portion B3. The section in the segment alignment portion 50 where the height of the segment 45 changes corresponds to the segment height variable section (circled 2 in FIG. 12a).

[0272] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In one variation, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of another embodiment (variation).

[0273] The end 101 of the segment 45 included in the segment alignment unit 50 may be bent in the radial direction of the electrode assembly 100, for example, from the outer periphery toward the core. At this time, the uncoated portions of the first portion B1 and the second portion B3 are not substantially bent.

[0274] Since the segment alignment portion 50 includes a plurality of segment pieces 45 aligned in the radial direction, bending stress is alleviated, thereby preventing tearing or abnormal deformation of the uncoated portions 43a, 43b near the bending points. Furthermore, when the width and / or height and / or spacing pitch of the segment pieces 45 are adjusted within the ranges of the above-mentioned embodiments, the segment pieces 45 are overlapped to an extent that sufficient welding strength can be ensured while being bent toward the core, and no open space (gap) is formed in the bent surface region F.

[0275] FIG. 14 is a cross-sectional view of an electrode assembly 110 according to yet another embodiment of the present invention, taken along the Y-axis direction (winding axis direction) so as to pass through the segment alignment unit 50. As shown in FIG.

[0276] Referring to Figure 14, the electrode assembly 110 is substantially identical in configuration to the electrode assembly 100 of Figure 13, except that the second part B3 also includes a segment 45 that forms the segment alignment portion 50, and the height of the segment 45 of the second part B3 is substantially the same as the height of the outermost segment 45 of the third part B2.

[0277] In the electrode assembly 110, the height of the uncoated portion of the first portion B1 is relatively lower than the height of the segment segments 45 included in the segment segment alignment portion 50. Furthermore, the bent length H of the segment segment 45 located at the innermost position in the segment segment alignment portion 50 is equal to or shorter than the radial length R of the winding turn formed by the first portion B1. Preferably, the winding turn formed by the first portion B1 may be a segment-omitted section (circled 1 in FIG. 12a) without a segment segment. In a variant, the bent length H may be smaller than the sum of the radial length R of the winding turn formed by the first portion B1 and 10% of the radius of the core 112.

[0278] Therefore, even if the segment pieces 45 included in the segment piece alignment unit 50 are bent, 90% or more of the diameter of the core 112 of the electrode assembly 110 is open to the outside. If the core 112 is not blocked, the electrolyte injection process can be performed without any problems, improving the efficiency of the electrolyte injection. In addition, a welding jig can be inserted through the core 112 to easily perform the welding process between the negative (or positive) electrode current collector plate and the battery housing (or rivet terminal).

[0279] In one variation, the structure in which the height of the segment 45 included in the segment alignment portion 50 increases gradually or in steps from the core side toward the outer periphery side may be extended to the winding turn formed by the second portion B3. In this case, the height of the segment 45 included in the segment alignment portion 50 may increase gradually or in steps from the boundary between the first portion B1 and the third portion B2 to the outermost surface of the electrode assembly 110.

[0280] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In one variation, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of another embodiment (variation).

[0281] The end 111 of the segment 45 included in the segment alignment unit 50 may be bent in the radial direction of the electrode assembly 110, for example, from the outer periphery toward the core. At this time, the uncoated portion of the first portion B1 is not substantially bent.

[0282] Since the segment alignment portion 50 includes a plurality of segment pieces 45 aligned in the radial direction, bending stress is alleviated, thereby preventing tearing or abnormal deformation of the uncoated portions 43a, 43b near the bending points. Furthermore, when the width and / or height and / or spacing pitch of the segment pieces 45 are adjusted within the ranges of the numerical values ​​of the above-mentioned embodiment, the segment pieces 45 are overlapped to an extent that sufficient welding strength can be ensured while being bent toward the core, and no open spaces (gaps) are formed in the bent surface area.

[0283] FIG. 15 is a cross-sectional view of an electrode assembly 120 according to yet another embodiment of the present invention, taken along the Y-axis direction (winding axis direction) so as to pass through the segment alignment unit 50. As shown in FIG.

[0284] 15, the electrode assembly 120 is substantially identical in configuration to the electrode assembly 100 of FIG. 13, except that the heights of the segment 45 included in the segment alignment portion 50 gradually or stepwise increase and then decrease. The radius section where the height of the segment 45 varies may be considered a variable-height section of the segment (circled 2 in FIG. 12a). In this case, too, the variable-height section of the segment 45 may be designed so that a uniform stack number section, where the number of stacked segments is 10 or more, appears in the above-mentioned preferred numerical range in the folded surface region F formed as the segment 45 is folded.

[0285] In the electrode assembly 120, the height of the uncoated portion of the first portion B1 is relatively shorter than the height of the segment 45. The bent length H of the segment 45 closest to the core 122 is equal to or shorter than the radial length R of the winding turn formed by the first portion B1. The section corresponding to the winding turn formed by the first portion B1 corresponds to the segment-omitted section (circled 1 in FIG. 12a) where no segment is present. In a variant, the bent length H may be smaller than the sum of the radial length R of the winding turn formed by the first portion B1 and 10% of the radius of the core 102.

[0286] Therefore, even if the segment pieces 45 included in the segment piece alignment unit 50 are bent toward the core side, 90% or more of the diameter of the core 122 of the electrode assembly 120 is open to the outside. If the core 122 is not blocked, the electrolyte injection process can be performed without any problems, improving the efficiency of the electrolyte injection. In addition, a welding jig can be inserted through the core 122 to easily perform the welding process between the negative (or positive) side current collector plate and the battery housing (or rivet terminal).

[0287] In addition, the height of the uncoated portion of the second part B3 is relatively lower than the height of the divisional piece 45, and preferably, the divisional piece 45 may not be formed on the second part B3. Therefore, when the beading portion of the battery housing is pressed near the wound turn formed by the second part B3, it is possible to prevent the beading portion and the periphery of the electrode assembly 120 from coming into contact with each other, causing an internal short circuit. In one variation, the second part B3 may include divisional pieces that form the divisional piece alignment portion 50, and the height of the divisional pieces of the second part B3 may gradually or stepwise decrease toward the outer periphery.

[0288] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a modified example, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of another embodiment (modified example).

[0289] The end 121 of the segment 45 included in the segment alignment unit 50 may be bent from the outer periphery of the electrode assembly 120 toward the core. At this time, the uncoated portions of the first portion B1 and the second portion B3 are not substantially bent.

[0290] Since the segment alignment portion 50 includes a plurality of segment pieces 45 aligned in the radial direction, bending stress is alleviated, thereby preventing tearing or abnormal deformation of the uncoated portions 43a, 43b. In addition, when the width and / or height and / or spacing pitch of the segment pieces 45 are adjusted within the range of the values ​​in the above-mentioned embodiment, the segment pieces 45 are overlapped to an extent that sufficient welding strength can be ensured while being bent toward the core, and no open space (gap) is formed in the bent surface region F.

[0291] FIG. 16 is a cross-sectional view of an electrode assembly 130 according to yet another embodiment of the present invention, taken along the Y-axis direction (winding axis direction) so as to pass through the segment alignment unit 50. As shown in FIG.

[0292] Referring to Figure 16, the electrode assembly 130 is substantially identical in configuration to the electrode assembly 120 of Figure 15, except that the second part B3 includes a segment 45 that forms a segment alignment portion 50, and the height of the segment 45 has a pattern in which it gradually or stepwise decreases from the boundary between the second part B3 and the third part B2 toward the outermost surface of the electrode assembly 130.

[0293] In the electrode assembly 130, the height of the uncoated portion of the first portion B1 is relatively shorter than the height of the segment 45. The bent length H of the segment 45 closest to the core 132 is equal to or shorter than the radial length R of the winding turn formed by the first portion B1. The winding turn formed by the first portion B1 corresponds to the segment-omitted section (circled 1 in FIG. 12a) where no segment is present. In a variant, the bent length H may be smaller than the sum of the radial length R of the winding turn formed by the first portion B1 and 10% of the radius of the core 102.

[0294] Therefore, even if the segment pieces 45 included in the segment piece alignment unit 50 are bent toward the core side, 90% or more of the diameter of the core 132 of the electrode assembly 130 is open to the outside. If the core 132 is not blocked, the electrolyte injection process is not hindered and the efficiency of the electrolyte injection is improved. In addition, a welding jig can be inserted through the core 132 to easily perform the welding process between the negative (or positive) side current collector plate and the battery housing (or rivet terminal).

[0295] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In one variation, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of another embodiment (variation).

[0296] The end 131 of the segment 45 included in the segment alignment unit 50 may be bent from the outer periphery of the electrode assembly 130 toward the core. At this time, the uncoated portion of the first portion B1 is not substantially bent.

[0297] Since the segment alignment portion 50 includes a plurality of segment pieces 45 aligned in the radial direction, bending stress is alleviated, thereby preventing tearing or abnormal deformation of the uncoated portions 43a, 43b near the bending points. Furthermore, when the width and / or height and / or spacing pitch of the segment pieces 45 are adjusted within the ranges of the above-mentioned embodiments, the segment pieces 45 are overlapped to an extent that sufficient welding strength can be ensured while being bent toward the core, and no open space (gap) is formed in the bent surface region F.

[0298] Meanwhile, in the above-described embodiment (variant), the end of the segment 45 included in the segment alignment portion 50 may be bent from the core side toward the outer periphery. In this case, it is preferable that the winding turn formed by the second portion B3 be designed as a segment-free section (circled 1 in FIG. 12a) without a segment and not be bent toward the outer periphery. Furthermore, the radial width of the winding turn formed by the second portion B3 may be equal to or greater than the length of the bent outermost segment. Therefore, when the outermost segment is bent toward the outer periphery, the end of the bent portion does not protrude beyond the outer periphery of the electrode assembly toward the inner surface of the battery housing. Furthermore, the structural change pattern of the segment included in the segment alignment portion 50 may be opposite to that of the above-described embodiment (variant). For example, the height of the segment may increase stepwise or gradually from the core side toward the outer periphery. That is, by sequentially arranging a section where segment pieces are omitted (circle 1 in Figure 12a), a section where segment piece heights are variable (circle 2 in Figure 12a), and a section where segment piece heights are uniform (circle 3 in Figure 12a) from the outer periphery side to the core side of the electrode assembly, it is possible to make a uniform stack number section where the number of segment piece stacks is 10 or more appear in a preferred numerical range in the folded surface region F.

[0299] Various electrode assembly structures according to embodiments of the present invention can be applied to jelly-roll type cylindrical batteries.

[0300] Preferably, the cylindrical battery may have a form factor ratio (defined as the diameter divided by the height of a cylindrical battery, i.e., the ratio of height (H) to diameter (Φ)) of greater than about 0.4, where form factor refers to the diameter and height of a cylindrical battery.

[0301] Preferably, the cylindrical battery has a diameter of 40mm to 50mm and a height of 70mm to 90mm. In one embodiment, the cylindrical battery may be, for example, a 46110 battery, a 4875 battery, a 48110 battery, a 4880 battery, or a 4680 battery. In the form factor number, the first two digits indicate the diameter of the battery, and the remaining digits indicate the height of the battery.

[0302] When an electrode assembly having a tabless structure is applied to a cylindrical battery with a form factor ratio exceeding 0.4, the uncoated portion is easily torn due to the large radial stress applied when the uncoated portion is bent. Furthermore, when welding a current collector plate to the bent surface area of ​​the uncoated portion, the number of layers of the uncoated portion in the bent surface area must be increased to ensure sufficient welding strength and reduce resistance. These requirements can be met by the electrode and electrode assembly according to an embodiment (variant) of the present invention.

[0303] A battery according to one embodiment of the present invention may be a generally cylindrical battery having a diameter of about 46 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0304] Another embodiment of the battery may be a generally cylindrical battery having a diameter of about 48 mm, a height of about 75 mm, and a form factor ratio of 0.640.

[0305] In yet another embodiment, the battery may be a generally cylindrical battery having a diameter of about 48 mm, a height of about 110 mm, and a form factor ratio of 0.436.

[0306] In yet another embodiment, the battery may be a generally cylindrical battery having a diameter of about 48 mm, a height of about 80 mm, and a form factor ratio of 0.600.

[0307] In yet another embodiment, the battery may be a generally cylindrical battery having a diameter of about 46 mm, a height of about 80 mm, and a form factor ratio of 0.575.

[0308] Conventionally, batteries with a form factor ratio of approximately 0.4 or less have been used. For example, 1865 batteries and 2170 batteries have been used. The 1865 battery has a diameter of approximately 18 mm, a height of approximately 65 mm, and a form factor ratio of 0.277. The 2170 battery has a diameter of approximately 21 mm, a height of approximately 70 mm, and a form factor ratio of 0.300.

[0309] Hereinafter, a cylindrical battery according to an embodiment of the present invention will be described in detail.

[0310] Figure 17 is a cross-sectional view of a cylindrical battery 190 according to one embodiment of the present invention, cut along the Y-axis direction passing through a folded surface area (F in Figure 12a) formed by bending the segment included in the segment alignment portion (50 in Figure 5).

[0311] Referring to FIG. 17, a cylindrical battery 190 according to one embodiment of the present invention includes an electrode assembly 110 including a first electrode, a separator, and a second electrode, a battery housing 142 that houses the electrode assembly 110, and a seal 143 that seals the open end of the battery housing 142.

[0312] The battery housing 142 is a cylindrical container with an opening at the top. The battery housing 142 is made of a conductive metal material such as aluminum, steel, or stainless steel. A nickel coating layer may be formed on the surface of the battery housing 142. The battery housing 142 accommodates the electrode assembly 110 in the internal space through the opening at the top, along with the electrolyte.

[0313] The electrolyte is A + B - where A+ Li + , Na + , K. + or a combination thereof. - is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , BF2C2O4 - , BC4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - The anion comprises one or more anions selected from the group consisting of:

[0314] The electrolyte may be dissolved in an organic solvent such as propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone, or a mixture thereof.

[0315] The electrode assembly 110 may have a jelly-roll structure. As shown in FIG. 2, the electrode assembly 110 may be manufactured by stacking a lower separator, a first electrode, an upper separator, and a second electrode in order at least once, and winding the stack around a winding center C.

[0316] The first electrode and the second electrode have opposite polarities. That is, one has a positive polarity and the other has a negative polarity. At least one of the first electrode and the second electrode may have an electrode structure according to the above-described embodiment (variant). The other of the first electrode and the second electrode may have a conventional electrode structure or an electrode structure according to the embodiment (variant). The number of electrode pairs included in the electrode assembly 110 is not limited to one, but may be two or more.

[0317] The upper and lower parts of the electrode assembly 110 are provided with segment alignment portions (50 in FIG. 5) formed by the segments included in the first uncoated portion 146a of the first electrode and the second uncoated portion 146b of the second electrode, respectively.

[0318] The segment pieces included in the segment piece aligning unit 50 are bent in the radial direction of the electrode assembly 110, for example, from the outer periphery side to the core side, thereby forming a bent surface region F.

[0319] The first portion B1 is shorter than the other portions and corresponds to the segment omitting section a1 having no segment, and therefore is not bent toward the core side.

[0320] Preferably, the folded surface region F may include, in order from the core side to the outer periphery side, a segment-omitted section a1, a segment-height variable section a2, and a segment-height uniform section a3.

[0321] As shown in FIGS. 12b, 12c, and 12d, the folded surface region F includes a section a1 where no segment is present and a section b1 where the number of stacked segments is uniform and where the number of stacked segments is 10 or more.

[0322] The folded surface region F may also include a layer number decreasing section b2 adjacent to the outer periphery of the electrode assembly 110, where the number of layers of the segment decreases toward the outer periphery. Preferably, the layer number uniform section b1 may be set as a welding target region.

[0323] In the folded surface region F, the ratio (a2 / c) of the height variable section a2 of the segment, based on the radial length (c) in which the segment exists, the ratio (b1 / c) of the uniform number of layers section b1 of the segment, and the preferred numerical ranges of the ratio of the area of ​​the uniform number of layers section b1 to the area of ​​the folded surface region F have been described above, so repeated explanations will be omitted.

[0324] The first current collecting plate 144 may be laser welded to the bent surface area F of the first uncoated portion 146a, and the second current collecting plate 145 may be laser welded to the bent surface area F of the second uncoated portion 146b. The welding method may be ultrasonic welding, resistance welding, spot welding, or the like.

[0325] Preferably, 50% or more of the welding region W of the first current collector 144 and the second current collector 145 may overlap with the uniform lamination number section b1 of the folded surface region F. Optionally, the remaining region of the welding region W may overlap with the reduced lamination number section b2 of the folded surface region F. It is more preferable that the entire welding region W overlap with the uniform lamination number section b1 in terms of high welding strength, low resistance at the welding interface, and prevention of damage to the separator and active material layer.

[0326] Preferably, the number of layers of the divided pieces may be 10 to 35 in the uniform layer number section b1 overlapping the welding area W and optionally in the reduced layer number section b2.

[0327] Alternatively, if the number of layers in the divided section of the layer count reduction section b2 overlapping the welding area W is less than 10, the laser output in the layer count reduction section b2 can be lower than the laser output in the uniform layer count section b1. That is, if the welding area W overlaps the uniform layer count section b1 and the layer count reduction section b2 at the same time, the laser output can be changed depending on the number of layers in the divided section. In this case, the weld strength in the uniform layer count section b1 can be greater than the weld strength in the layer count reduction section b2.

[0328] In the folded surface region F formed on the upper and lower parts of the electrode assembly 110, the radial lengths of the segment-omitted section a1 and / or the segment-height variable section a2 and / or the segment-height uniform section a3 may be the same or different.

[0329] In the electrode assembly 110, the height of the uncoated portion of the first portion B1 is relatively lower than the other portions. Also, as shown in Fig. 14, the bent length H of the segment closest to the core is smaller than the sum of the radial length R of the winding turn formed by the first portion B1 and 10% of the radius of the core 112.

[0330] Therefore, even if the segments included in the segment alignment unit 50 are bent toward the core, 90% or more of the diameter of the core 112 of the electrode assembly 110 can be open to the outside. If the core 112 is not blocked, the electrolyte injection process can be performed without any problems, improving the efficiency of the electrolyte injection. In addition, a welding jig can be inserted through the core 112 to easily perform the welding process between the second current collector plate 145 and the battery housing 142.

[0331] If the width and / or height and / or spacing pitch of the segments are adjusted to satisfy the numerical ranges of the above-mentioned embodiments, when the segments are bent, the segments overlap each other to an extent that sufficient welding strength is ensured, and no open spaces (gaps) are formed in the bent surface area F.

[0332] Preferably, the first current collector plate 144 and the second current collector plate 145 may have an outer diameter that covers the ends of the folded segments (see 45 in FIG. 12e) of the last winding turn of the first and second electrodes. In this case, welding is possible with the segments forming the folded surface area F evenly pressed by the current collector plates, and the segments can be maintained in a tightly stacked state even after welding. A tightly stacked state means that there are substantially no gaps between the segments, as shown in FIG. 12. The tightly stacked state contributes to reducing the resistance of the cylindrical battery 190 to a level suitable for fast charging (e.g., 4 mΩ) or less.

[0333] The sealing body 143 may include a cap plate 143a, a first gasket 143b having insulating properties and providing airtightness between the cap plate 143a and the battery housing 142, and a connecting plate 143c electrically and mechanically connected to the cap plate 143a.

[0334] The cap plate 143a is a component made of a conductive metal material and covers the upper opening of the battery housing 142. The cap plate 143a is electrically connected to the bent surface region F of the first electrode and is electrically insulated from the battery housing 142 via the first gasket 143b. Therefore, the cap plate 143a can function as a first electrode terminal (e.g., a positive electrode) of the cylindrical battery 190.

[0335] The cap plate 143a is placed on a beading portion 147 formed on the battery housing 142 and fixed by a crimping portion 148. A first gasket 143b may be interposed between the cap plate 143a and the crimping portion 148 to ensure airtightness of the battery housing 142 and to provide electrical insulation between the battery housing 142 and the cap plate 143a. The cap plate 143a may have a protrusion 143d formed to protrude upward from the center thereof.

[0336] The battery housing 142 is electrically connected to the bent surface area F of the second electrode. Therefore, the battery housing 142 has the same polarity as the second electrode. If the second electrode has a negative polarity, the battery housing 142 also has a negative polarity.

[0337] The battery housing 142 has a beading portion 147 and a crimping portion 148 at its upper end. The beading portion 147 is formed by pressing in around the outer periphery of the battery housing 142. The beading portion 147 prevents the electrode assembly 110 housed inside the battery housing 142 from slipping out of the upper opening of the battery housing 142, and can also function as a support on which the sealing body 143 is placed.

[0338] The second portion B3 of the first electrode does not include a segment and may be notched in the same structure as the first portion B1. Preferably, the inner circumferential surface of the beading portion 147 is spaced a predetermined distance from the winding turn formed by the second portion B3 of the first electrode. This is because the second portion B3 is notched like the first portion B1. More specifically, the lower end of the inner circumferential surface of the beading portion 147 is spaced a predetermined distance from the winding turn formed by the second portion B3 of the first electrode. Furthermore, because the uncoated portion of the second portion B3 has a low height, the winding turn of the second portion B3 is substantially unaffected even when the battery housing 142 is pressed from the outside to form the beading portion 147. Therefore, the winding turn of the second portion B3 is not compressed by other components such as the beading portion 147, which prevents partial deformation of the electrode assembly 110 and internal short circuits in the cylindrical battery 190.

[0339] Preferably, the relationship D1≦D2 can be satisfied, where D1 is the pressing depth of the beading portion 147 and D2 is the radial length from the inner circumferential surface of the battery housing 142 to the boundary point between the second portion B3 and the third portion B2. In this case, when the battery housing 142 is pressed to form the beading portion 147, damage to the wound turns formed by the second portion B3 is substantially prevented.

[0340] The crimping portion 148 is formed on the upper portion of the beading portion 147. The crimping portion 148 is extended and bent to enclose the outer circumferential surface of the cap plate 143a disposed on the beading portion 147 and a part of the upper surface of the cap plate 143a.

[0341] The cylindrical battery 190 may further include a first current collector 144 and / or a second current collector 145 and / or an insulator 146 .

[0342] The first current collecting plate 144 is coupled to the upper part of the electrode assembly 110. The first current collecting plate 144 is made of a conductive metal material such as aluminum, copper, steel, nickel, etc., and is electrically connected to the bent surface region F of the first electrode. The electrical connection may be made by welding. A lead 149 may be connected to the first current collecting plate 144. The lead 149 may extend upwardly of 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. The lead 149 may be coupled to other components by welding.

[0343] Preferably, the first current collector 144 may be formed integrally with the lead 149. In this case, the lead 149 may have a long plate shape extending outward from near the center of the first current collector 144.

[0344] The first current collecting plate 144 and the bent surface region F of the first electrode may be joined by, for example, laser welding. Laser welding may be performed by partially melting the base material of the current collecting plate. In a modified example, the first current collecting plate 144 and the bent surface region F may be welded together using solder. In this case, the solder may have a lower melting point than the first current collecting plate 144 and the first uncoated portion 146a. Laser welding may be replaced by resistance welding, ultrasonic welding, spot welding, etc.

[0345] A second current collecting plate 145 may be coupled to the lower surface of the electrode assembly 110. One surface of the second current collecting plate 145 may be coupled to the folded surface region F of the second electrode by welding, and the other surface may be coupled to the inner bottom surface of the battery housing 142 by welding. The coupling structure between the second current collecting plate 145 and the folded surface region F of the second electrode may be substantially the same as the coupling structure between the first current collecting plate 144 and the folded surface region F of the first electrode.

[0346] The insulator 146 may cover the first current collector 144. By covering the first current collector 144 on the upper surface of the first current collector 144, the insulator 146 can prevent direct contact between the first current collector 144 and the inner circumferential surface of the battery housing 142.

[0347] The insulator 146 has a lead hole 151 through which the lead 149 extending upward from the first current collector plate 144 is drawn out. The lead 149 is drawn out upward through the lead hole 151 and is coupled to the lower surface of the connecting plate 143c or the lower surface of the cap plate 143a.

[0348] The peripheral region of the insulator 146 may be interposed between the first current collector plate 144 and the beading portion 147 to fix the combination of the electrode assembly 110 and the first current collector plate 144. This limits the movement of the combination of the electrode assembly 110 and the first current collector plate 144 in the height direction of the battery 140, thereby improving the assembly stability of the battery 140.

[0349] The insulator 146 may be made of an insulating polymer resin. For example, the insulator 146 may be made of polyethylene, polypropylene, polyimide, or polybutylene terephthalate.

[0350] The battery housing 142 may further include a venting portion 152 formed on its bottom surface. The venting portion 152 corresponds to a region on the bottom surface of the battery housing 142 that is thinner than the surrounding region. The venting portion 152 is structurally weaker than the surrounding region. Therefore, if an abnormality occurs in the cylindrical battery 190 and the internal pressure increases above a certain level, the venting portion 152 may burst, allowing the gas generated inside the battery housing 142 to be released to the outside. The internal pressure at which the venting portion 152 bursts is approximately 15 kgf / cm. 2 ~35kgf / cm 2 It could be.

[0351] The vents 152 may be formed continuously or discontinuously in a circular pattern on the underside of the battery housing 142. Alternatively, the vents 152 may be formed in a linear pattern or other patterns.

[0352] FIG. 18 is a cross-sectional view of a cylindrical battery 200 according to another embodiment of the present invention, cut along the Y-axis direction passing through a folded surface area (F in FIG. 12a) formed by bending the segment included in the segment alignment portion (50 in FIG. 5).

[0353] Referring to FIG. 18, a cylindrical battery 200 has substantially the same electrode assembly structure as the cylindrical battery 190 shown in FIG. 17, but differs in that other structures except for the electrode assembly have been changed.

[0354] Specifically, the cylindrical battery 200 includes a battery housing 171 having a rivet terminal 172 extending therethrough. The rivet terminal 172 is attached through a through-hole formed in the closed surface (top surface in the drawing) of the battery housing 171. The rivet terminal 172 is riveted into the through-hole of the battery housing 171 with a second gasket 173 made of an insulating material interposed therebetween. The rivet terminal 172 is exposed outward in the direction opposite to the direction of gravity.

[0355] The rivet terminal 172 includes a terminal exposure portion 172a and a terminal insertion portion 172b. The terminal exposure portion 172a is exposed to the outside of the closed surface of the battery housing 171. The terminal exposure portion 172a may be located approximately at the center of the closed surface of the battery housing 171. The maximum diameter of the terminal exposure portion 172a may be larger than the maximum diameter of the through-hole formed in the battery housing 171. The terminal insertion portion 172b may penetrate approximately the center of the closed surface of the battery housing 171 to be electrically connected to the uncoated portion 146a of the first electrode. The lower peripheral edge of the terminal insertion portion 172b may be rivet-connected to the inner surface of the battery housing 171. That is, the lower peripheral edge of the terminal insertion portion 172b may be bent toward the inner surface of the battery housing 171. A flat portion 172c may be included on the inner side of the lower peripheral edge of the terminal insertion portion 172b. The maximum diameter of the bottom of the riveted terminal insertion portion 172b may be larger than the maximum diameter of the through hole in the battery housing 171.

[0356] The flat portion 172c of the terminal insertion portion 172b may be welded to the center of the first current collecting plate 144 connected to the bent surface region F of the first electrode. Laser welding is preferred as the welding method, but other welding methods such as ultrasonic welding may be used instead.

[0357] An insulator 174 made of an insulating material may be interposed between the first current collecting plate 144 and the inner surface of the battery housing 171. The insulator 174 covers the upper portion of the first current collecting plate 144 and the upper peripheral edge portion of the electrode assembly 110. This prevents the second portion B3 of the electrode assembly 110 from coming into contact with the inner surface of the battery housing 171, which has the opposite polarity, and causing a short circuit.

[0358] The thickness of the insulator 174 corresponds to or is slightly larger than the distance between the upper surface of the first current collector 144 and the inner surface of the closed portion of the battery housing 171. Therefore, the insulator 174 can contact the upper surface of the first current collector 144 and the inner surface of the closed portion of the battery housing 171.

[0359] The terminal insertion portion 172b of the rivet terminal 172 may be welded to the first current collecting plate 144 through a through hole in the insulator 174. The diameter of the through hole formed in the insulator 174 may be larger than the diameter of the riveting portion at the lower end of the terminal insertion portion 172b. Preferably, the through hole may expose the lower portion of the terminal insertion portion 172b and the second gasket 173.

[0360] The second gasket 173 is interposed between the battery housing 171 and the rivet terminal 172 to prevent electrical contact between the battery housing 171 and the rivet terminal 172, which have opposite polarities. This allows the upper surface of the battery housing 171, which has a substantially flat shape, to function as a second electrode terminal (e.g., a negative electrode) of the cylindrical battery 200.

[0361] The second gasket 173 includes a gasket exposing portion 173a and a gasket inserting portion 173b. The gasket exposing portion 173a is interposed between the terminal exposing portion 172a of the rivet terminal 172 and the battery housing 171. The gasket inserting portion 173b is interposed between the terminal inserting portion 172b of the rivet terminal 172 and the battery housing 171. The gasket inserting portion 173b may be deformed during riveting of the terminal inserting portion 172b, thereby adhering closely to the inner surface of the battery housing 171. The second gasket 173 may be made of, for example, an insulating polymer resin.

[0362] The gasket exposing portion 173a of the second gasket 173 may extend to cover the outer peripheral surface of the terminal exposing portion 172a of the rivet terminal 172. When the second gasket 173 covers the outer peripheral surface of the rivet terminal 172, it is possible to prevent a short circuit from occurring during the process of connecting an electrical connection component such as a bus bar to the upper surface of the battery housing 171 and / or the rivet terminal 172. Although not shown, the gasket exposing portion 173a may extend to cover not only the outer peripheral surface of the terminal exposing portion 172a but also a portion of the upper surface.

[0363] When the second gasket 173 is made of a polymer resin, the second gasket 173 may be joined to the battery housing 171 and the rivet terminal 172 by heat sealing. In this case, the airtightness at the joining interface between the second gasket 173 and the rivet terminal 172 and at the joining interface between the second gasket 173 and the battery housing 171 is strengthened. Meanwhile, when the gasket exposed portion 173a of the second gasket 173 has a shape that extends to the upper surface of the terminal exposed portion 172a, the rivet terminal 172 may be joined integrally with the second gasket 173 by insert injection molding.

[0364] On the upper surface of the battery housing 171, a region 175 other than the region occupied by the rivet terminal 172 and the second gasket 173 corresponds to a second electrode terminal having a polarity opposite to that of the rivet terminal 172.

[0365] The second current collecting plate 176 is coupled to the lower part of the electrode assembly 141. The second current collecting plate 176 is made of a conductive metal material such as aluminum, steel, copper, or nickel, and is electrically connected to the bent surface region F of the second electrode.

[0366] Preferably, second current collecting plate 176 is electrically connected to battery housing 171. Therefore, second current collecting plate 176 may be fixed with at least a portion of its peripheral edge interposed between the inner surface of battery housing 171 and first gasket 178b. As an example, at least a portion of the peripheral edge of second current collecting plate 176 may be fixed to beading portion 180 by welding while being supported on a lower end surface of beading portion 180 formed at the lower end of battery housing 171. In a modified example, at least a portion of the peripheral edge of second current collecting plate 176 may be directly welded to the inner wall surface of battery housing 171.

[0367] Preferably, the second current collecting plate 176 and the folded surface region F of the second electrode may be joined by, for example, laser welding. In addition, the welded portion between the second current collecting plate 176 and the folded surface region F is spaced a predetermined distance from the inner circumferential surface of the beading portion 180 toward the core C.

[0368] The sealing body 178, which seals the lower open end of the battery housing 171, includes a cap plate 178a and a first gasket 178b. The first gasket 178b electrically isolates the cap plate 178a from the battery housing 171. The crimping portion 181 secures the periphery of the cap plate 178a to the first gasket 178b. The cap plate 178a is provided with a vent portion 179. The configuration of the vent portion 179 is substantially the same as in the above-described embodiment (variant). The lower surface of the cap plate 178a may be located higher than the lower end of the crimping portion 181. In this case, a space is formed below the cap plate 178a, allowing for smooth venting. This is particularly useful when the cylindrical battery 200 is installed with the crimping portion 181 facing the direction of gravity.

[0369] Preferably, the cap plate 178a is made of a conductive metal material. However, since the first gasket 178b is interposed between the cap plate 178a and the battery housing 171, the cap plate 178a does not have electrical polarity. The sealing body 178 seals the open end of the lower part of the battery housing 171 and mainly functions to discharge gas when the internal pressure of the battery 200 increases above a critical value. The critical value of the internal pressure is 15 kgf / cm. 2 ~35kgf / cm 2 is.

[0370] Preferably, the rivet terminal 172 electrically connected to the bent surface region F of the first electrode is used as the first electrode terminal. Furthermore, a portion 175 of the upper surface of the battery housing 171, excluding the rivet terminal 172, electrically connected to the bent surface region F of the second electrode through the second current collector plate 176 is used as a second electrode terminal having the opposite polarity to the first electrode terminal. When two electrode terminals are located on the upper portion of the cylindrical battery 200, electrical connection components such as bus bars can be disposed on only one side of the cylindrical battery 200. This simplifies the battery pack structure and improves energy density. Furthermore, the portion 175 used as the second electrode terminal has a substantially flat shape, ensuring a sufficient contact area for connecting electrical connection components such as bus bars. This allows the cylindrical battery 200 to reduce resistance at the contact points of the electrical connection components to a desirable level.

[0371] FIG. 19 is a cross-sectional view of a cylindrical battery 210 according to another embodiment of the present invention, cut along the Y-axis direction passing through a folded surface area (F in FIG. 12a) formed by bending the segment included in the segment alignment portion (50 in FIG. 5).

[0372] 19, a cylindrical battery 210 includes the electrode assembly 100 shown in FIG. 13, and other configurations except for the electrode assembly 100 are substantially the same as the cylindrical battery 190 shown in FIG. 17. Therefore, the configurations described with reference to FIGS. 13 and 17 can be applied substantially in the same manner to this embodiment.

[0373] Preferably, the first uncoated portion 146a and the second uncoated portion 146b of the electrode assembly 100 include a plurality of segment groups 61g. The plurality of segment groups 61g form segment alignment portions (50 in FIG. 5) at the top and bottom of the electrode assembly 100. The segment 45 included in the segment alignment portion 50 are bent in the radial direction of the electrode assembly 100, for example, from the outer periphery toward the core. In this case, the uncoated portions of the first portion B1 and the second portion B3 of the first uncoated portion 146a are lower in height than the other portions and do not include segment pieces, so they are not substantially bent. The same is true for the second uncoated portion 146b.

[0374] In this embodiment, the folded surface region F formed by the segments included in the segment alignment portion (50 in FIG. 5) may include, from the core side to the outer periphery, a segment-omitted section a1, a segment-height variable section a2, and a segment-height uniform section a3. However, because the plain portion of the second portion B3 is not folded, the radial length of the folded surface region F may be shorter than in the above-described embodiment.

[0375] As shown in FIGS. 12b, 12c, and 12d, the folded surface region F includes a section a1 where no segment is present and a section b1 where the number of stacked segments is uniform and where the number of stacked segments is 10 or more.

[0376] The folded surface region F may also include a layer count decreasing section b2 in which the number of layers of the segment decreases toward the outer periphery adjacent to the winding turns of the second portion B3 of the electrode assembly 100. Preferably, the layer count uniform section b1 may be set as a welding target region.

[0377] In the folded surface region F, the ratio (a2 / c) of the height variable section a2 of the segment, based on the radial length (c) in which the segment exists, the ratio (b1 / c) of the uniform number of layers section b1 of the segment, and the preferred numerical ranges of the ratio of the area of ​​the uniform number of layers section b1 to the area of ​​the folded surface region F have been described above, so repeated explanations will be omitted.

[0378] The first current collecting plate 144 may be welded to the bent surface area F of the first uncoated portion 146a, and the second current collecting plate 145 may be welded to the bent surface area F of the second uncoated portion 146b.

[0379] The overlapping relationship between the uniform stack count section b1 and the reduced stack count section b2 and the welding area W, the outer diameters of the first current collector plate 144 and the second current collector plate 145, and the configuration in which the first portion B1 does not block the core are essentially as described above.

[0380] On the other hand, the second portion B3 does not include a divided segment, and the height of the uncoated portion is lower than that of the divided segment of the third portion B2. Therefore, when the divided segment of the third portion B2 is bent, the second portion B3 is not substantially bent. In addition, the wound turns of the second portion B3 are sufficiently spaced apart from the beading portion 147, which solves the problem of the wound turns of the second portion B3 being damaged when the beading portion 147 is pressed in.

[0381] Figure 20 is a cross-sectional view of a cylindrical battery 220 according to another embodiment of the present invention, cut along the Y-axis direction passing through a folded surface area (F in Figure 12a) formed by bending the segment included in the segment alignment portion (50 in Figure 5).

[0382] 20, a cylindrical battery 220 includes the electrode assembly 100 shown in FIG. 13, and other configurations except for the electrode assembly 100 are substantially the same as the cylindrical battery 200 shown in FIG. 18. Therefore, the configurations described with reference to FIGS. 13 and 18 can be applied substantially similarly to this embodiment.

[0383] Preferably, the first uncoated portion 146a and the second uncoated portion 146b of the electrode assembly 100 include a plurality of segment groups 61g, which are aligned radially to form a segment alignment portion (50 in FIG. 5). The segments included in the segment alignment portion 50 are bent from the outer periphery of the electrode assembly 100 toward the core, forming a bent surface region F. The first and second portions B1 and B3 of the first uncoated portion 146a are not substantially bent toward the core because they are lower in height than the other portions and do not include any segment pieces. The same is true for the second uncoated portion 146b.

[0384] 19, the folded surface region F may include, from the core side to the outer periphery, a segment-free section a1, a segment-height variable section a2, and a segment-height uniform section a3. However, because the plain portion of the second portion B3 is not folded, the radial length of the folded surface region F may be shorter than in the above-described embodiment.

[0385] As shown in FIGS. 12b, 12c, and 12d, the folded surface region F includes a section a1 where no segment is present and a section b1 where the number of stacked segments is uniform and where the number of stacked segments is 10 or more.

[0386] The folded surface region F may also include a layer count decreasing section b2 in which the number of layers of the segment decreases toward the outer periphery adjacent to the winding turns of the second portion B3 of the electrode assembly 100. Preferably, the layer count uniform section b1 may be set as a welding target region.

[0387] In the folded surface region F, the ratio (a2 / c) of the height variable section a2 of the segment, based on the radial length (c) in which the segment exists, the ratio (b1 / c) of the uniform number of layers section b1 of the segment, and the preferred numerical ranges of the ratio of the area of ​​the uniform number of layers section b1 to the area of ​​the folded surface region F have been described above, so repeated explanations will be omitted.

[0388] The first current collector 144 may be welded to the bent surface area F of the first uncoated portion 146a, and the second current collector 176 may be welded to the bent surface area F of the second uncoated portion 146b.

[0389] The overlapping relationship between the uniform stack count section b1 and the reduced stack count section b2 and the welding area W, the outer diameters of the first current collector plate 144 and the second current collector plate 176, and the configuration in which the first portion B1 does not block the core are essentially as described above.

[0390] In the above-described embodiment (variant), the first current collector plate 144 and the second current collector plate 176 included in the cylindrical batteries 200, 220 including the rivet terminals 172 may have an improved structure as shown in Figures 21 and 22.

[0391] The improved structure of the first current collector plate 144 and the second current collector plate 176 can contribute to lowering the resistance of the cylindrical battery, improving vibration resistance, and increasing the energy density. The first current collector plate 144 and the second current collector plate 176 are particularly effective when applied to large cylindrical batteries with a height-to-diameter ratio of greater than 0.4.

[0392] FIG. 21 is a top view showing the structure of a first current collector plate 144 according to an embodiment of the present invention.

[0393] 20 and 21, the first current collecting plate 144 may include a peripheral portion 144a, a first non-coating portion coupling portion 144b, and a terminal coupling portion 144c. The peripheral portion 144a is disposed on the upper portion of the electrode assembly 100. The peripheral portion 144a has an empty space S therein. open The peripheral portion 144a may have a substantially rim shape formed thereon. Although the drawings only show the case where the peripheral portion 144a has a substantially circular rim shape, the present invention is not limited thereto. Unlike the illustrations, the peripheral portion 144a may have a substantially square rim shape, a hexagonal rim shape, an octagonal rim shape, or other rim shapes. The number of peripheral portions 144a may be increased to two or more. In this case, another rim-shaped peripheral portion may be included inside the peripheral portion 144a.

[0394] The terminal coupling portion 144c may have a diameter equal to or larger than the diameter of the flat portion 172c formed on the bottom surface of the rivet terminal 172 to ensure a welding area for coupling with the flat portion 172c formed on the bottom surface of the rivet terminal 172.

[0395] The first non-coating portion coupling portion 144b extends inward from the peripheral portion 144a and is coupled to the bent surface region F of the non-coating portion 146a by welding. The terminal coupling portion 144c is spaced apart from the first non-coating portion coupling portion 144b and is positioned inside the peripheral portion 144a. The terminal coupling portion 144c may be coupled to a rivet terminal 172 by welding. The terminal coupling portion 144c is, for example, in an inner space S surrounded by the peripheral portion 144a. open The terminal coupling portion 144c may be provided at a position corresponding to a hole formed in the core C of the electrode assembly 100. The terminal coupling portion 144c may be configured to cover the hole formed in the core C of the electrode assembly 100 so that the hole formed in the core C of the electrode assembly 100 is not exposed to the outside of the terminal coupling portion 144c. Therefore, the terminal coupling portion 144c may have a diameter or width larger than the hole formed in the core C of the electrode assembly 100.

[0396] The first non-coating portion coupling portion 144b and the terminal coupling portion 144c may be spaced apart and indirectly coupled via the peripheral portion 144a. In this manner, the first current collecting plate 144 has a structure in which the first non-coating portion coupling portion 144b and the terminal coupling portion 144c are not directly coupled but are coupled via the peripheral portion 144a. This allows for dispersion of impacts applied to the coupling portion between the first non-coating portion coupling portion 144b and the first non-coating portion 146a and the coupling portion between the terminal coupling portion 144c and the rivet terminal 172 when shock and / or vibration occurs to the cylindrical battery 220. While four first non-coating portion coupling portions 144b are shown in the drawings, the present invention is not limited thereby. The number of first non-coating portion coupling portions 144b may be determined based on the inner space S of the peripheral portion 144a, taking into consideration the difficulty of manufacturing due to the complexity of the shape, electrical resistance, and electrolyte impregnation. open It can be determined in various ways, taking into consideration the above.

[0397] The first current collecting plate 144 may further include a bridge portion 144d extending inward from the peripheral portion 144a and connecting to the terminal connecting portion 144c. The bridge portion 144d may have at least a portion having a smaller cross-sectional area than the first non-coating portion connecting portion 144b and the peripheral portion 144a. For example, the bridge portion 144d may have at least a portion having a smaller width and / or thickness than the first non-coating portion connecting portion 144b. In this case, electrical resistance increases in the bridge portion 144d. As a result, when current flows through the bridge portion 144d, the relatively large resistance causes a portion of the bridge portion 144d to melt due to overcurrent heating, irreversibly interrupting the overcurrent. The cross-sectional area of ​​the bridge portion 144d may be adjusted to an appropriate level in consideration of this overcurrent interruption function.

[0398] The bridge portion 144d may include a tapered portion 144e whose width gradually narrows from the inner surface of the peripheral portion 144a toward the terminal coupling portion 144c. The tapered portion 144e improves the rigidity of the component at the connection portion between the bridge portion 144d and the peripheral portion 144a. The tapered portion 144e allows, for example, a transfer device and / or a worker to grip the tapered portion 144e during the manufacturing process of the cylindrical battery 220, thereby allowing the first current collecting plate 144 and / or the combination of the first current collecting plate 144 and the electrode assembly 100 to be easily and safely transported. That is, the tapered portion 144e can prevent product defects caused by gripping portions to be welded to other components, such as the first uncoated portion coupling portion 144b and the terminal coupling portion 144c.

[0399] The first non-coating portion joining portions 144b may be provided in plurality. The first non-coating portion joining portions 144b may be disposed at equal intervals along the extension direction of the peripheral portion 144a. The first non-coating portion joining portions 144b may have substantially the same extension length. The first non-coating portion joining portions 144b may be joined to the folded surface region F of the non-coating portion 146a by laser welding. The welding may be substituted by ultrasonic welding, spot welding, etc.

[0400] The welding pattern 144f formed by welding the first non-coating portion joining portion 144b and the bent surface region F may have a structure extending along the radial direction of the electrode assembly 100. The welding pattern 144f may be an array of lines or dots.

[0401] The welding pattern 144f corresponds to a welding region. Therefore, it is preferable that the welding pattern 144f overlaps with the uniform layer count section b1 of the folded surface region F by 50% or more. The welding pattern 144f that does not overlap with the uniform layer count section b1 may overlap with the reduced layer count section b2. More preferably, the entire welding pattern 144f may overlap with the uniform layer count section b1 of the folded surface region F. It is preferable that the uniform layer count section b1 and optionally the reduced layer count section b2 of the folded surface region F below the point where the welding pattern 144f is formed have a number of laminated sections of 10 or more.

[0402] The terminal coupling portion 144c may be disposed to be surrounded by the plurality of first non-coating portion coupling portions 144b. The terminal coupling portion 144c may be coupled to the flat portion 172c of the rivet terminal 172 by welding. The bridge portion 144d may be located between a pair of adjacent first non-coating portion coupling portions 144b. In this case, the distance from the bridge portion 144d to one of the pair of first non-coating portion coupling portions 144b along the extension direction of the peripheral portion 144a may be approximately the same as the distance from the bridge portion 144d to the other of the pair of first non-coating portion coupling portions 144b along the extension direction of the peripheral portion 144a. The cross-sectional area of ​​each of the plurality of first non-coating portion coupling portions 144b may be approximately the same. The width and thickness of each of the plurality of first non-coating portion coupling portions 144b may be approximately the same.

[0403] Although not shown, a plurality of bridge portions 144d may be provided. Each of the plurality of bridge portions 144d may be disposed between an adjacent pair of first non-coating portion joining portions 144b. The plurality of bridge portions 144d may be disposed at substantially equal intervals from one another along the extension direction of the peripheral portion 144a. The distance from each of the plurality of bridge portions 144d to one of the adjacent pair of first non-coating portion joining portions 144b along the extension direction of the peripheral portion 144a may be substantially the same as the distance to the other first non-coating portion joining portion 144b.

[0404] As described above, when a plurality of first uncoated portion joining portions 144b and / or bridge portions 144d are provided, if the distance between the first uncoated portion joining portions 144b and / or the distance between the bridge portions 144d and / or the distance between the first uncoated portion joining portions 144b and the bridge portions 144d are constant, a current can smoothly flow from the first uncoated portion joining portions 144b to the bridge portions 144d or from the bridge portions 144d to the first uncoated portion joining portions 144b.

[0405] The bridge portion 144d may include a notch N formed to partially reduce the cross-sectional area of ​​the bridge portion 144d. The adjustment of the cross-sectional area of ​​the notch N can be achieved, for example, by partially reducing the width and / or thickness of the bridge portion 144d. When the notch N is provided, the electrical resistance in the region where the notch N is formed increases, thereby enabling rapid current interruption when an overcurrent occurs.

[0406] The notched portion N is preferably provided in a region corresponding to a uniform lamination section of the electrode assembly 100 to prevent foreign matter generated during breakage from entering the electrode assembly 100. This is because the number of laminations of the uncoated portion 146a is maximized in this region, allowing the overlapping laminations to function as a mask.

[0407] The notched portion N may be wrapped with insulating tape, so that heat generated at the notched portion N is not dissipated to the outside, and therefore the notched portion N breaks more quickly when an overcurrent flows through the bridge portion 144d.

[0408] FIG. 22 is a top view showing the structure of a second current collector plate 176 according to one embodiment of the present invention.

[0409] 20 and 22, the second current collecting plate 176 is disposed at the bottom of the electrode assembly 100. The second current collecting plate 176 may be configured to electrically connect the uncoated portion 146b of the electrode assembly 100 to the battery housing 171. The second current collecting plate 176 is made of a conductive metal material and is electrically connected to the bent surface region F of the uncoated portion 146b. The second current collecting plate 176 is also electrically connected to the battery housing 171. A peripheral portion of the second current collecting plate 176 may be interposed and fixed between the inner surface of the battery housing 171 and the first gasket 178b. Specifically, a peripheral portion of the second current collecting plate 176 may be interposed between the lower surface of the beading portion 180 of the battery housing 171 and the first gasket 178b. However, this does not limit the present invention, and instead, the peripheral portion of the second current collecting plate 176 may be welded to the inner wall surface of the battery housing 171 in an area where the beading portion 180 is not formed.

[0410] The second current collecting plate 176 may include a support portion 176a disposed at a lower portion of the electrode assembly 100, a second non-coating portion coupling portion 176b extending from the support portion 176a substantially along the radial direction of the electrode assembly 100 and coupled to the bent surface region F of the non-coating portion 146b, and a housing coupling portion 176c extending from the support portion 176a at an angle substantially toward the inner surface of the battery housing 171 relative to the radial direction of the electrode assembly 100 and coupled to the inner surface. The second non-coating portion coupling portion 176b and the housing coupling portion 176c are indirectly coupled to each other via the support portion 176a and are not directly coupled to each other. Therefore, when an external impact is applied to the cylindrical battery 220 according to one embodiment of the present invention, damage to the coupling portions between the second current collecting plate 176 and the electrode assembly 100 and between the second current collecting plate 176 and the battery housing 171 can be minimized. However, the second current collecting plate 176 according to an embodiment of the present invention is not limited to having a structure in which the second uncoated portion coupling portion 176b and the housing coupling portion 176c are indirectly coupled to each other. For example, the second current collecting plate 176 may have a structure without the support portion 176a that indirectly couples the second uncoated portion coupling portion 176b and the housing coupling portion 176c and / or a structure in which the uncoated portion 146b and the housing coupling portion 176c are directly coupled to each other.

[0411] The support portion 176a and the second non-coating portion joining portion 176b are disposed at the bottom of the electrode assembly 100. The second non-coating portion joining portion 176b is joined to the folded surface region F of the non-coating portion 146b. Not only the second non-coating portion joining portion 176b but also the support portion 176a may be joined to the non-coating portion 146b. The second non-coating portion joining portion 176b and the folded surface region F of the non-coating portion 146b may be joined by laser welding. Welding may be replaced by ultrasonic welding, spot welding, or the like. If a beading portion 180 is formed on the battery housing 171, the support portion 176a and the second non-coating portion joining portion 176b are located above the beading portion 180.

[0412] The support portion 176a has a current collecting plate hole 176d formed at a position corresponding to a hole formed in the core C of the electrode assembly 100. The core C of the electrode assembly 100 and the current collecting plate hole 176d, which are in communication with each other, can function as a passage for inserting a welding rod or irradiating a laser beam for welding between the rivet terminal 172 and the terminal coupling portion 144c of the first current collecting plate 144.

[0413] The current collecting plate hole 176d has a radius r c 0.5r to c The radius of the current collecting plate hole 176d may be 0.5r or more. c ~1.0r c In this case, when venting occurs in the cylindrical battery 220, the separator and the electrode winding structure near the core C of the electrode assembly 100 are prevented from being pushed out of the core C by the vent pressure. c When the core C is larger than 1 / 2, the core C is opened to the maximum extent, which makes it easier to inject the electrolyte in the electrolyte injection step.

[0414] When a plurality of second uncoated portion coupling portions 176b are provided, the plurality of second uncoated portion coupling portions 176b may extend radially from the support portion 176a of the second current collector plate 176 toward the sidewall of the battery housing 171. The plurality of second uncoated portion coupling portions 176b may be spaced apart from one another along the periphery of the support portion 176a.

[0415] A plurality of the housing coupling portions 176c may be provided. In this case, the plurality of housing coupling portions 176c may extend radially from the center of the second current collecting plate 176 toward the sidewall of the battery housing 171. This allows electrical connection between the second current collecting plate 176 and the battery housing 171 at multiple points. By coupling for electrical connection at multiple points, the coupling area can be maximized and electrical resistance can be minimized. The plurality of housing coupling portions 176c may be spaced apart from one another along the periphery of the support portion 176a. At least one housing coupling portion 176c may be located between adjacent second non-coating portion coupling portions 176b. The plurality of housing coupling portions 176c may be coupled to the inner surface of the battery housing 171, for example, to the beading portion 180. The housing coupling portion 176c may be coupled to the lower surface of the beading portion 180 by laser welding. The welding may be substituted by ultrasonic welding, spot welding, or the like. By welding a plurality of housing coupling portions 176c onto the beading portion 180 in this manner, the current path is dispersed radially, thereby limiting the resistance level of the cylindrical battery 220 to approximately 4 mΩ or less. In addition, by forming the lower surface of the beading portion 180 to extend in a direction approximately parallel to the upper surface of the battery housing 171, i.e., in a direction approximately perpendicular to the sidewall of the battery housing 171, and forming the housing coupling portions 176c to extend in the same direction, i.e., in the radial and circumferential directions, the housing coupling portions 176c can be stably contacted onto the beading portion 180. In addition, because the housing coupling portions 176c are stably contacted onto the flat portions of the beading portion 180 in this manner, welding between the two components is performed smoothly, thereby improving the bonding strength between the two components and minimizing the increase in resistance at the bonding site.

[0416] The housing coupling portion 176c may include a contact portion 176e coupled to the inner surface of the battery housing 171, and a coupling portion 176f connecting the support portion 176a and the contact portion 176e.

[0417] The contact portion 176e is coupled to an inner surface of the battery housing 171. If a beading portion 180 is formed in the battery housing 171, the contact portion 176e may be coupled to the beading portion 180 as described above. More specifically, the contact portion 176e may be electrically coupled to a flat portion formed on the lower surface of the beading portion 180 formed in the battery housing 171, and may be interposed between the lower surface of the beading portion 180 and the first gasket 178b. In this case, for stable contact and coupling, the contact portion 176e may extend a predetermined length in the beading portion 180 along the circumferential direction of the battery housing 171.

[0418] The connecting portion 176f may be bent at an obtuse angle. The bending point may be higher than the midpoint of the connecting portion 176f. When the connecting portion 176f is bent, the contact portion 176e is stably supported on the flat surface of the beading portion 180. The connecting portion 176f may be divided into a lower portion and an upper portion based on the bending point, and the length of the lower portion may be greater than that of the upper portion. In addition, the inclination angle based on the surface of the support portion 176a may be greater at the lower portion at the bending point than at the upper portion. When the connecting portion 176f is bent, it can buffer pressure (force) applied vertically to the battery housing 171. For example, when pressure is transmitted to the contact portion 176e during the sizing process of the battery housing 171 and the contact portion 176e moves vertically toward the support portion 176a, the bending point of the connecting portion 176f moves upward, deforming the connecting portion 176f, thereby buffering stress.

[0419] Meanwhile, the maximum distance from the center of the second current collector plate 176 to the end of the second uncoated portion joining portion 176b along the radial direction of the electrode assembly 100 is preferably equal to or smaller than the inner diameter of the battery housing 171 in the region where the beading portion 180 is formed, i.e., the minimum inner diameter of the battery housing 171. This is to prevent the end of the second uncoated portion joining portion 176b from pressing against the end of the electrode assembly 100 during a sizing process in which the battery housing 171 is compressed in the height direction.

[0420] The second non-coating portion joining portion 176b includes holes 176g. The holes 176g can be used as passages for electrolyte movement. A welding pattern 176h formed by welding the second non-coating portion joining portion 176b to the bent surface region F can have a structure extending along the radial direction of the electrode assembly 100. The welding pattern 176h can be an array of lines or dots.

[0421] The welding pattern 176h corresponds to a welding region. Therefore, it is preferable that the welding pattern 176h overlaps with the uniform lamination number section b1 of the folded surface region F located at the bottom of the electrode assembly 100 by 50% or more. The welding pattern 176h that does not overlap with the uniform lamination number section b1 may overlap with the reduced lamination number section b2. More preferably, the entire welding pattern 176h may overlap with the uniform lamination number section b1 of the folded surface region F. It is preferable that the uniform lamination number section b1 and, optionally, the reduced lamination number section b2 of the folded surface region F located above the point where the welding pattern 176h is formed have a divisional section with a lamination number of 10 or more.

[0422] The first current collector plate 144 and the second current collector plate 176 have different outer diameters. The outer diameter is the outer diameter of the contact area between the folded surface region F and the current collector plate. The outer diameter is defined as the maximum distance between two points where a line passing through the center of the core C of the electrode assembly intersects with the edge of the contact area. Because the second current collector plate 176 is located inside the beading portion, its outer diameter is smaller than that of the first current collector plate 144. In addition, the length of the welding pattern 144f of the first current collector plate 144 is longer than the length of the welding pattern 176h of the second current collector plate 176. Preferably, the welding pattern 144f and the welding pattern 176h may extend radially outward from substantially the same point relative to the center of the core C.

[0423] The cylindrical batteries 200 and 220 according to the present invention may be electrically connected at the top.

[0424] Fig. 23 is a top view showing a state in which a plurality of cylindrical batteries 200 are electrically connected, and Fig. 24 is a partially enlarged view of Fig. 23. The cylindrical battery 200 can be replaced with a cylindrical battery 220 having a different structure.

[0425] 23 and 24, a plurality of cylindrical batteries 200 may be connected in series and parallel at the top of the cylindrical batteries 200 using bus bars 210. The number of cylindrical batteries 200 may be increased or decreased depending on the capacity of the battery pack.

[0426] In each cylindrical battery 200, the rivet terminal 172 may have a positive polarity, and the flat surface 171a around the rivet terminal 172 of the battery housing 171 may have a negative polarity. Of course, the opposite is also possible.

[0427] Preferably, the cylindrical batteries 200 may be arranged in a plurality of rows and columns. In the drawings, columns are arranged in the vertical direction, and rows are arranged in the horizontal direction. Furthermore, to maximize space efficiency, the cylindrical batteries 200 may be arranged in the closest packing structure. The closest packing structure is formed when an equilateral triangle is drawn when the centers of the rivet terminals 172 exposed on the outside of the battery housing 171 are connected to each other. Preferably, the bus bars 210 connect the cylindrical batteries 200 arranged in the same column in parallel with each other, and connect the cylindrical batteries 200 arranged in two adjacent columns in series with each other.

[0428] Preferably, the bus bar 210 may include a body portion 211, a plurality of first bus bar terminals 212, and a plurality of second bus bar terminals 213 for series and parallel connection.

[0429] The body portion 211 may extend along the row of cylindrical batteries 200 between adjacent rivet terminals 172. Alternatively, the body portion 211 may extend along the row of cylindrical batteries 200 but may be bent regularly, such as in a zigzag shape.

[0430] The plurality of first bus bar terminals 212 may extend from one side of the body portion 211 and be electrically coupled to the rivet terminals 172 of the cylindrical battery 200 located on the one side. The electrical coupling between the first bus bar terminals 212 and the rivet terminals 172 may be performed by laser welding, ultrasonic welding, or the like.

[0431] The plurality of second bus bar terminals 213 may extend from the other side of the body portion 211 and be electrically coupled to the flat surface 171a around the rivet terminals 172 located on the other side. The electrical coupling between the second bus bar terminals 213 and the flat surface 171a may be performed by laser welding, ultrasonic welding, or the like.

[0432] Preferably, the body portion 211, the plurality of first bus bar terminals 212, and the plurality of second bus bar terminals 213 may be formed from a single conductive metal plate. The metal plate may be, for example, an aluminum plate or a copper plate, but the present invention is not limited thereto. Alternatively, the body portion 211, the plurality of first bus bar terminals 212, and the second bus bar terminals 213 may be manufactured as separate pieces and then joined together by welding or the like.

[0433] The cylindrical battery 200 according to the embodiment of the present invention has a structure in which resistance is minimized by expanding the welding area through the bent surface area F, multiplexing the current paths using the second current collector plate 176, and minimizing the length of the current paths. The AC resistance of the cylindrical battery 200 measured by a resistance meter between the positive and negative electrodes, i.e., between the rivet terminal 172 and the surrounding flat surface 171a, may be approximately 4 mΩ or less, which is suitable for fast charging.

[0434] In the cylindrical battery 200 according to one embodiment of the present invention, the rivet terminal 172 having a positive polarity and the flat surface 171a having a negative polarity are positioned in the same direction, so that electrical connection between the cylindrical batteries 200 can be easily achieved using the bus bar 210.

[0435] In addition, since the rivet terminal 172 of the cylindrical battery 200 and the surrounding flat surface 171a have a large area, the connection area of ​​the bus bar 210 can be sufficiently secured, thereby sufficiently reducing the resistance of the battery pack including the cylindrical battery 200.

[0436] In addition, since electrical wiring can be performed on the top of the cylindrical battery 200, the energy density per unit volume of the battery module / pack can be maximized.

[0437] The cylindrical battery according to the above-described embodiment (variant) is used to manufacture a battery pack.

[0438] FIG. 25 is a diagram schematically illustrating the configuration of a battery pack according to one embodiment of the present invention.

[0439] 25, a battery pack 300 according to an embodiment of the present invention includes an assembly of electrically connected cylindrical batteries 301 and a pack housing 302 that accommodates the assembly. The cylindrical batteries 301 may be any one of the batteries according to the above-described embodiments (variants). For convenience of illustration, components such as bus bars for electrical connection of the cylindrical batteries 301, a cooling unit, and external terminals are not shown.

[0440] The battery pack 300 is mounted on a vehicle. The vehicle may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle may be a four-wheeled vehicle or a two-wheeled vehicle.

[0441] FIG. 26 is a diagram illustrating a vehicle including the battery pack 300 of FIG.

[0442] 26, an automobile V according to an embodiment of the present invention includes a battery pack 300 according to an embodiment of the present invention. The automobile V operates by receiving a supply of power from the battery pack 300 according to an embodiment of the present invention.

[0443] According to an embodiment of the present invention, the uncoated portions protruding from the upper and lower sides of the electrode assembly are used as electrode tabs, thereby reducing the internal resistance of the battery and increasing the energy density.

[0444] Furthermore, according to one embodiment of the present invention, the structure of the uncoated portion of the electrode assembly is improved so that the electrode assembly does not interfere with the inner surface of the battery housing during the process of forming the beading portion of the battery housing, thereby preventing internal short circuits in cylindrical batteries due to partial deformation of the electrode assembly.

[0445] Furthermore, according to one embodiment of the present invention, the structure of the uncoated portion of the electrode assembly is improved to prevent the uncoated portion from being torn when the uncoated portion is bent, and the number of overlapping layers of the uncoated portion is sufficiently increased to improve the welding strength of the current collector plate.

[0446] In addition, according to one embodiment of the present invention, a plurality of segments are formed in an uncoated portion of the electrode, and when the electrode is wound up, the plurality of segments are aligned in a predetermined direction. In areas where no segments are arranged, the ends of the active material layer formed on the electrode are exposed between the wound turns of the separator, thereby increasing the electrolyte impregnation rate.

[0447] In addition, according to one embodiment of the present invention, by applying a segment structure to the uncoated portion of the electrode and optimizing the dimensions (width, height, and spacing pitch) of the segments, the number of segments stacked in the area used as the welding target area can be sufficiently increased, thereby improving the physical properties of the area where the current collector plate is welded.

[0448] Furthermore, according to one embodiment of the present invention, a structure in which a current collector plate is welded over a wide area to a folded surface region formed by bending a segmented piece is applied, thereby providing an electrode assembly with improved energy density and reduced resistance.

[0449] Furthermore, according to one embodiment of the present invention, a cylindrical battery with an improved design that allows electrical wiring to be performed at the top can be provided.

[0450] Furthermore, according to one embodiment of the present invention, the structure of the uncoated portion adjacent to the core of the electrode assembly is improved to prevent the cavity in the core of the electrode assembly from being blocked when the uncoated portion is bent, facilitating the electrolyte injection process and the welding process between the battery housing (or rivet terminal) and the current collector plate.

[0451] Furthermore, according to one embodiment of the present invention, it is possible to provide a cylindrical battery having a structure in which internal resistance is low, internal short circuits are prevented, and welding strength between a current collector plate and a non-coating portion is improved, as well as a battery pack and a vehicle including the same.

[0452] In particular, the present invention can provide a cylindrical battery having a height-to-diameter ratio of 0.4 or more and a resistance of 4 mΩ or less, a battery pack including the same, and a vehicle.

[0453] As described above, the present invention has been described using limited embodiments and drawings, but the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims. [Explanation of symbols]

[0454] 40 electrodes 41 Current collector 42 Active material layer 43 Plain area 43a First plain section 43b 2nd plain area 44 insulating coating layer 45 min sectioning 46 Cutting groove 47 Bending point 50 min section alignment section 60 Electrolyte impregnated part 100 electrode assembly 110 Electrode assembly 120 Electrode assembly 130 Electrode assembly 140 Battery 141 Electrode assembly 142 Battery housing 143 Sealed body 144 First current collector plate 145 Second current collector plate 146 Insulators 146a First plain section 146b Second plain section 147 Beading section 148 Crimping section 149 leads 151 Lead hole 152 Venting section 171 Battery housing 172 Rivet terminal 173 Second gasket 174 Insulators 176 Second current collector plate 178 Sealed body 179 Vent 180 Beading section 181 Crimping section 190 Cylindrical Battery 200 Cylindrical Battery 210 Busbar 211 Body 212 First bus bar terminal 213 Second bus bar terminal 220 Cylindrical Battery 300 battery pack 301 Cylindrical Battery 302 Pack Housing

Claims

1. An electrode assembly in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode around a winding shaft, the first electrode includes a first active material portion coated with an active material layer along a winding direction, and a first uncoated portion not coated with an active material layer, the first uncoated portion includes a plurality of segments that can be independently bent along the winding direction and are exposed to the outside of the separator; The plurality of segments are aligned in a radial direction of the electrode assembly while overlapping each other to form a plurality of segment alignment portions spaced apart in a circumferential direction, The electrode assembly includes an electrolyte-impregnated portion where an end of the first active material portion is exposed between the wound turns of the separator between the adjacent segment alignment portions in the circumferential direction.

2. The electrode assembly according to claim 1 , wherein the segment aligning portions are defined as electrode tabs when folded along the radial direction of the electrode assembly.

3. The electrode assembly according to claim 1 or 2, wherein the plurality of segment alignment portions extend radially along the radial direction of the electrode assembly.

4. The electrode assembly according to claim 1 or 2, wherein the plurality of segment alignment portions are arranged at equal intervals along the circumferential direction of the electrode assembly.

5. 5. The electrode assembly according to claim 4, wherein an angle between adjacent segment alignment portions in the circumferential direction of the electrode assembly is 90 degrees, 120 degrees, or 180 degrees.

6. The electrode assembly according to claim 1 or 2, wherein the plurality of segments have the same length in the winding direction.

7. The electrode assembly according to claim 1 or 2, wherein the lengths of the plurality of segments in the winding direction gradually increase.

8. The electrode assembly according to claim 1 or 2, wherein the plurality of segment alignment portions have a rectangular or fan shape when viewed from the direction of the winding axis of the electrode assembly.

9. 3. The electrode assembly according to claim 1, wherein an area of ​​the electrolyte-impregnated portion is larger than an area of ​​the plurality of segment alignment portions when viewed in the direction of the winding axis of the electrode assembly.

10. 3. The electrode assembly of claim 1, wherein in a cross section of the electrolyte-impregnated portion cut along the winding shaft, an end of the first active material portion is spaced toward an inner side of the electrode assembly relative to an end of the separator.

11. 11. The electrode assembly of claim 10, wherein the distance between the end of the first active material portion and the end of the separator is 0.6 mm to 1.0 mm.

12. 3. The electrode assembly according to claim 1, wherein the winding direction lengths and pitches of the plurality of segment pieces are assigned values ​​that are approximately the same as mathematically designed values ​​using predetermined winding direction lengths of the segment pieces based on an approximate winding turn structure in which semicircles with periodically increasing radii are connected in the winding direction, and angles between adjacent segment piece alignment portions in the circumferential direction.

13. The n+1th pitch D adjacent to the n+1th segment along the winding direction ｎ＋１ is expressed by the following formula 1. [Formula 1] ケース1:D ｎ＋１ =θ Ｄｎ＋１ *R ｎ＋１ = (90k-θ) Ａｎ＋１ )*R ｎ＋１ ケース2:D ｎ＋１ =θ Ｄｎ＋１ * (R ｎ +R ｎ＋１ ) / 2=(90゜-θ Ａｎ＋１ )*(R ｎ +R ｎ＋１ ) / 2 (n is an integer of 0 or more; the starting point of the first semicircle corresponds to the position of the first segment in the winding direction; R ｎ is the radius of the nth semicircle; R ｎ＋１ is the radius of the n+1th semicircle; θ Ａｎ＋１ is the inscribed angle of the n+1th segment; θ Ｄｎ＋１ is the inscribed angle for the pitch of the n+1th segment; the formula for Case 1 is the n+1th pitch D ｎ＋１ The formula for Case 2 is the formula for the n+1 pitch D ｎ＋１ (The formula applied when the arc corresponding to the nth semicircle is located between the nth semicircle and the n+1th semicircle) 13. The electrode assembly of claim 12, wherein the electrode is assigned a value substantially equal to the value determined using

14. 14. The electrode assembly of claim 13, wherein the radius of the semicircle increases by Δ / 2 (Δ is a symbol indicating the spacing between adjacent winding turns) every 1 / 2 winding turn.

15. The electrode assembly according to claim 14 , wherein the symbol Δ is assigned a value substantially equal to the sum of the thickness of one positive electrode, the thickness of one negative electrode, and the thickness of two separators.

16. 3. The electrode assembly according to claim 1, wherein a cutting groove is interposed between adjacent segments in the winding direction, and a lower portion of the cutting groove includes a bottom portion and rounded portions connecting both ends of the bottom portion to side edges of the segments on both sides of the cutting groove.

17. The electrode assembly of claim 16 , wherein the bottom of the cutting groove is spaced a predetermined distance from the active material layer.

18. The electrode assembly of claim 17, wherein a distance between the lower end of the cutting groove and the active material layer is 0.2 mm to 4 mm.

19. 17. The electrode assembly of claim 16, wherein an insulating coating layer is formed at a boundary between the active material layer and an uncoated region present in a section where the bottom of the cut groove and the active material layer are separated.

20. The electrode assembly of claim 1 or 2, wherein the plurality of segment alignment portions include a radial section in which the height of the segments increases from a core side to an outer periphery side of the electrode assembly.

21. The plurality of segment alignment portions have a first height h from the core side to the outer periphery side of the electrode assembly. １ ~ N-1th height h Ｎ－１ (N is a natural number of 3 or more) and a variable height section where the height is increased stepwise up to N height h Ｎ (h Ｎ－１ 3. The electrode assembly according to claim 1, further comprising a uniform height section that is maintained uniformly at a height greater than 1 / 2.

22. Height h ｋ (k is a natural number from 1 to N) The starting radius of the winding turn containing the segment is r ｋ When the core of the electrode assembly is defined as ｋ 22. The electrode assembly of claim 21, wherein 90% or more of the diameter is not obstructed by the bends of the segment located at the positions.

23. Height h ｋ (k is a natural number from 1 to N) The starting radius of the winding turn containing the segment is r ｋ , the radius of the core is r ｃ Then, the height of the segment h ｋ is expressed by the following formula 2 [Formula 2] 2 mm ≦ h ｋ ≦r ｋ -α*r ｃ (a is 0.90 to 1) The electrode assembly according to claim 21 , wherein

24. 3. The electrode assembly of claim 1, wherein the plurality of segment alignment portions include, in order along a radial direction based on a cross section along the winding axis, a segment omission section where no segments are present, a height variable section where the height of the segments varies, and a height uniform section where the height of the segments is uniform, and the plurality of segments are arranged in the height variable section and the height uniform section and are bent along a radial direction of the electrode assembly to form a bent surface region extending along the radial direction.

25. 25. The electrode assembly of claim 24, wherein the number of laminations of the segment pieces at a radial position of the folded surface region is defined as the number of laminations of the segment pieces intersecting a virtual line parallel to the winding axis direction at the radial position of the folded surface region relative to the center of the core of the electrode assembly, and the folded surface region includes a uniform lamination number section in which the number of laminations of the segment pieces is uniform from the core side to the outer periphery, and a decreasing lamination number section located outside the uniform lamination number section in which the number of laminations of the segment pieces decreases toward the outer periphery.

26. The electrode assembly of claim 25, wherein the number of stacked segments in the uniform stacking section is 10 to 35.

27. 26. The electrode assembly of claim 25, wherein the first electrode is a positive electrode, and the thickness of the laminated pieces in the uniform laminated number section is 100 μm to 875 μm.

28. 26. The electrode assembly of claim 25, wherein the first electrode is a negative electrode, and the thickness of the laminated pieces in the uniform laminated number section is 50 μm to 700 μm.

29. 3. The electrode assembly of claim 1, wherein the second electrode includes a second active material portion coated with an active material layer along the winding direction and a second uncoated portion not coated with an active material layer, the second uncoated portion including a plurality of segments that can be independently bent along the winding direction and are exposed to the outside of the separator, the plurality of segments of the second uncoated portion being aligned along the radial direction of the electrode assembly to form a plurality of segment alignment portions spaced apart in the circumferential direction, and an end of the second active material portion between adjacent segment alignment portions of the second uncoated portion in the circumferential direction includes an electrolyte-impregnated portion exposed between the wound turns of the separator.

30. an electrode assembly in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed between the first and second electrodes around a winding shaft, the first electrode including a first active material portion coated with an active material layer along the winding direction and a first uncoated portion not coated with the active material layer, the first uncoated portion including a plurality of segments that can be independently bent along the winding direction and exposed to the outside of the separator, the plurality of segments being aligned in an overlapping manner along a radial direction of the electrode assembly to form a plurality of segment alignment portions spaced apart in a circumferential direction, and an electrode assembly in which ends of the first active material portion include electrolyte-impregnated portions exposed between the wound turns of the separator between adjacent segment alignment portions in the circumferential direction; a battery housing including an open end and a bottom portion opposite the open end, the battery housing accommodating the electrode assembly in a space between the open end and the bottom portion, the battery housing being electrically connected to one of the first electrode and the second electrode and having a first polarity; a seal that seals the open end of the battery housing; a terminal of a second polarity electrically connected to the other of the first electrode and the second electrode and having an exposed surface.

31. 31. The battery of claim 30, further comprising a first current collecting plate electrically connected to the first uncoated portion, wherein the terminal is a rivet terminal insulatively attached to a through hole formed in a bottom of the battery housing, electrically connected to the first current collecting plate, and having the second polarity.

32. 32. The battery of claim 31, further comprising an insulator interposed between an inner surface of the bottom of the battery housing and an upper surface of the first current collector plate to electrically insulate the inner surface of the bottom of the battery housing from the first current collector plate.

33. 33. The battery of claim 32, wherein the rivet terminal includes a flat portion at a bottom end, the insulator includes an opening that exposes the flat portion, and the flat portion is welded to the first current collector plate through the opening.

34. 34. The battery of claim 30, wherein the second electrode includes a second active material portion coated with an active material layer along the winding direction and a second uncoated portion not coated with an active material layer, the second electrode having the first polarity, at least a portion of the second uncoated portion being defined as an electrode tab, and the battery further includes a second current collector plate electrically connected to the second uncoated portion and having at least a portion of its periphery attached to a side wall of the battery housing.

35. 35. The battery of claim 34, wherein the cell housing includes a beading portion pressed inwardly on an inner wall adjacent an open end, and the periphery of the second current collector plate is electrically connected to the beading portion.

36. 36. The battery of claim 35, comprising: a cap plate having a non-polarity and a periphery supported by the beading portion; a gasket interposed between the periphery of the cap plate and the open end of the battery housing; and a crimping portion extending inward from the open end of the battery housing and bent to wrap around and secure the periphery of the cap plate together with the gasket, wherein the periphery of the second current collector plate is interposed and secured between the beading portion and the gasket by the crimping portion.

37. 34. The battery of claim 30, wherein the electrode assembly includes, in order along a radial direction with respect to a cross section taken along the winding axis, a segment-free section where no segments are present, a height-variable section where the height of the segments varies, and a height-uniform section where the height of the segments is uniform, and the plurality of segments are arranged in the height-variable section and the height-uniform section and are folded along the radial direction of the electrode assembly to form a folded surface region.

38. 38. The battery of claim 37, wherein the number of laminations of the segment pieces at a radial position of the folded surface region is defined as the number of laminations of the segment pieces intersecting a virtual line parallel to the winding axis direction at the radial position of the folded surface region relative to the center of the core of the electrode assembly, and the folded surface region includes a uniform lamination number section in which the number of laminations of the segment pieces is uniform from the core side to the outer periphery side, and a decreasing lamination number section located adjacent to the uniform lamination number section and in which the number of laminations of the segment pieces decreases with increasing distance from the uniform lamination number section.

39. The battery according to claim 38, wherein the uniform stacking number section has 10 to 35 stacked pieces.

40. The battery according to claim 38, wherein the first electrode is a positive electrode, and the thickness of the divided pieces in the uniform stacking number section is 100 μm to 875 μm.

41. The battery of claim 38, wherein the first electrode is a negative electrode, and the thickness of the divided pieces in the uniform stacking number section is 50 μm to 700 μm.

42. 39. The battery of claim 38, further comprising a current collector plate welded to the bent surface region, wherein the welded region of the current collector plate overlaps with the uniform stack number section by at least 50% in the radial direction of the electrode assembly.

43. 34. The battery of any one of claims 30 to 33, wherein the battery is cylindrical and has a height to diameter ratio of greater than 0.

4.

44. 44. The battery of claim 43, wherein the battery is cylindrical and has a form factor of 46110, 4875, 48110, 4880, or 4680.

45. 34. The battery of any one of claims 30 to 33, wherein the resistance of the battery is 4 mΩ or less.

46. 34. A battery pack comprising a plurality of batteries according to any one of claims 30 to 33.

47. the plurality of batteries are cylindrical; 47. The battery pack of claim 46, wherein the plurality of batteries are arranged in a predetermined number of rows, and are arranged so that the electrode terminals of each battery and the outer surface of the bottom of the battery housing face upward.

48. 48. The battery pack of claim 47, comprising: a plurality of bus bars connecting the plurality of batteries in series and parallel, the plurality of bus bars being disposed on top of the plurality of batteries, each bus bar including: a body portion extending between electrode terminals of adjacent batteries; a plurality of first bus bar terminals extending to one side of the body portion and electrically coupled to the electrode terminals of the batteries located on the one side; and a plurality of second bus bar terminals extending to the other side of the body portion and electrically coupled to outer surfaces of bottoms of cell housings of the batteries located on the other side.

49. 47. A motor vehicle including the battery pack of claim 46.

50. An electrode assembly in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode around a winding shaft, the first electrode includes a first active material portion coated with an active material layer along a winding direction, and a first uncoated portion not coated with an active material layer, the first uncoated portion includes a plurality of segments that can be independently bent along the winding direction and are exposed to the outside of the separator; The plurality of segments are aligned in a radial direction of the electrode assembly while overlapping each other to form a plurality of segment alignment portions spaced apart in a circumferential direction, the lengths and pitches of the plurality of segments in the winding direction are set such that, in each segment alignment portion, all of the segments constituting the segment alignment portion overlap along the radial direction of the electrode assembly; The electrode assembly includes an electrolyte-impregnated portion where an end of the first active material portion is exposed between the wound turns of the separator between the adjacent segment alignment portions in the circumferential direction.

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