Electrode assemblies, batteries, battery packs containing them, and automobiles

Abstract

The present invention provides an electrode assembly having an improved plain section structure that can alleviate the stress applied to the plain section when the plain section exposed at both ends of the electrode assembly is bent. [Solution] The present invention discloses an electrode assembly, a battery, a battery pack, and an automobile. In the electrode assembly, a first blank portion provided at the long side end of a first electrode includes a segment section, which is divided into a plurality of segment sections that can be independently bent by a plurality of cutting grooves provided along the winding direction. The segment section includes a plurality of segment section groups arranged along the winding direction with spacing between groups. The plurality of segment section groups constitute one or more segment section alignment sections on one side of the electrode assembly. At least a portion of the central points of the arc of the winding turn in which the p segment section groups included in the segment section alignment section are located are not located on a predetermined alignment line extending radially from the center of the core.

Description

[Technical Field]

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

[0002] This application claims priority based on Korean Patent Application No. 10-2021-0160823, filed on 19 November 2021, and all contents disclosed in the specification and drawings of said application are incorporated herein by reference. [Background technology]

[0003] Rechargeable batteries, which offer high applicability across different product groups and possess electrical characteristics such as high energy density, are commonly used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) powered by electric drive sources.

[0004] Such secondary batteries are attracting attention not only for their primary benefit of dramatically reducing the use of fossil fuels, but also because they are environmentally friendly in that they produce no by-products from energy use, making them a promising new energy source for improving energy efficiency.

[0005] Currently, rechargeable 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 a single rechargeable battery, i.e., a single battery, is approximately 2.5V to 4.5V. Therefore, when a higher output voltage is required, multiple batteries are connected in series to form a battery pack. Alternatively, multiple batteries may be connected in parallel to form a battery pack, depending on the required charge and discharge capacity. Thus, the number of batteries included in a battery pack and the electrical connection configuration can be set in various ways depending on the required output voltage and / or charge and discharge capacity.

[0006] On the other hand, known types of rechargeable batteries include cylindrical, prismatic, and pouch-type batteries. In the case of a cylindrical battery, an insulating separator membrane is interposed between the positive and negative electrodes, and this is wound up to form a jelly-roll type electrode assembly, which is then inserted into the battery housing to constitute the battery. The battery housing is called a battery can in this industry. Strip-shaped electrode tabs are connected to the blank portions of the positive and negative electrodes, and these electrode tabs electrically connect the electrode assembly to the electrode terminals exposed on the outside. For reference, the positive electrode terminal is the cap of the sealing body that seals the opening of the battery housing, and the negative electrode terminal is the battery housing. However, with conventional cylindrical batteries having such a structure, current is concentrated in the strip-shaped electrode tabs connected to the blank portion of the positive electrode and / or the blank portion of the negative electrode, resulting in high resistance, high heat generation, and poor current collection efficiency.

[0007] In small cylindrical batteries with form factors such as 1865 (diameter: 18mm, height: 65mm) and 2170 (diameter: 21mm, height: 70mm), resistance and heat generation are not much of a problem. However, when increasing the form factor of cylindrical batteries for application in electric vehicles, a problem can arise where the cylindrical battery catches fire during the rapid charging process due to the large amount of heat generated around the electrode tabs.

[0008] To solve these problems, a cylindrical battery (a so-called tab-less cylindrical battery) has been proposed in which a blank positive electrode section and a blank negative electrode section are located at the upper and lower ends of a jelly roll-type electrode assembly, respectively, and a current collector is welded to these blank sections to improve current collection efficiency.

[0009] Figures 1 to 3 illustrate the manufacturing process of a tablet cylindrical battery. Figure 1 shows the structure of the electrodes, Figure 2 shows the electrode winding process, and Figure 3 shows the process of welding the current collector to the bent surface area of ​​the plain section.

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

[0011] Electrode assembly A is manufactured by sequentially stacking the positive electrode 10 and the negative electrode 11 together with two separation films 12, as shown in Figure 2, and then winding them in one direction (the X-axis direction). At this time, the plain portion of the positive electrode 10 and the plain portion of the negative electrode 11 are positioned in opposite directions.

[0012] After the winding process, the plain portion 10a of the positive electrode 10 and the plain portion 11a of the negative electrode 11 are bent towards the core. Then, the current collectors 30 and 31 are welded to the plain portions 10a and 11a, respectively, to join them.

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

[0014] In a tablet cylindrical battery, in order to improve the welding characteristics between the plain sections 10a and 11a and the current collectors 30 and 31, strong pressure must be applied to the welding area of ​​the plain sections 10a and 11a to bend them as flat as possible.

[0015] However, when the welded areas of the plain sections 10a and 11a are bent, the patterns of the plain sections 10a and 11a may be irregularly distorted and deformed. In this case, the deformed parts may come into contact with electrodes of opposite polarity, causing an internal short circuit, or it may induce fine cracks in the plain sections 10a and 11a. Also, the plain section 32 adjacent to the core of electrode assembly A may be bent, blocking all or a portion of the cavity 33 in the core of electrode assembly A. In this case, problems arise in the electrolyte injection process. That is, the cavity 33 in the core of electrode assembly A is used as a passage for electrolyte injection. However, if this passage is blocked, it becomes difficult to inject the electrolyte. In addition, when the electrolyte injector is inserted into the cavity 33, it may interfere with the plain section 32 near the core, potentially causing the plain section 32 to tear.

[0016] Furthermore, the bent portions of the plain sections 10a and 11a to which the current collectors 30 and 31 are welded must overlap multiple times. This ensures sufficient welding strength and prevents the problem of the laser penetrating into the electrode assembly A and melting the separation membrane or active material when using advanced technologies such as laser welding.

[0017] On the other hand, in the bent surface regions formed as the plain parts 10a and 11a of electrode assembly A are folded, there are almost no gaps in the winding axis direction through which the electrolyte can pass. This is because, during the process of folding the plain parts 10a and 11a, the gaps between winding turns that existed immediately after winding are almost completely eliminated. Therefore, in a structure in which the entire ends of the plain parts 10a and 11a are folded, the electrolyte impregnation time may increase. [Overview of the project] [Problems that the invention aims to solve]

[0018] The present invention was conceived against the background of the prior art described above, and one objective is to provide an electrode assembly having an improved plain section structure that can alleviate the stress applied to the plain section when the plain section exposed at both ends of the electrode assembly is bent.

[0019] Another objective of the present invention is to provide an electrode assembly in which the electrolyte injection passage is not blocked even if the plain portion is bent.

[0020] Furthermore, another object of the present invention is to provide an electrode assembly that includes a structure capable of preventing the upper peripheral edge of the electrode assembly from coming into contact with the inner surface of the battery housing when the upper end of the battery housing is beaded.

[0021] Furthermore, the present invention aims to provide an electrode assembly in which the physical properties of the welding area are improved by applying a segmentation structure to the plain portion of the electrode and optimizing the dimensions (width, height, and spacing pitch) of the segmentation segments to sufficiently increase the number of stacked segmentation segments in the area used as the welding target area.

[0022] Furthermore, the present invention aims to provide an electrode assembly with improved energy density and reduced resistance by applying a structure in which a current collector is welded over a wide area to a bent surface region formed by bending a segment.

[0023] Furthermore, another objective of the present invention is to provide an electrode assembly having a structure that allows for stable welding of a current collector to the electrode assembly.

[0024] Furthermore, another objective of the present invention is to provide an electrode assembly with improved electrolyte impregnation characteristics by arranging a plurality of segments radially in a localized region.

[0025] Furthermore, another objective of the present invention is to provide an electrode assembly that can stably secure the weld line of the current collector even when rotated clockwise or counterclockwise due to the thickness tolerance of the electrodes, when a plurality of subsections are arranged radially in a local region.

[0026] Furthermore, the present invention aims to provide a battery including terminals and current collectors with an improved design that allows for electrical wiring to be performed on top.

[0027] Furthermore, the present invention aims to provide a battery including an electrode assembly with an improved structure, a battery pack including the battery, and an automobile including the battery pack.

[0028] The technical problems that this invention aims to solve are not limited to those described above, and other problems will be clearly understood by an ordinary person from the following description of the invention. [Means for solving the problem]

[0029] To achieve the above objectives, an electrode assembly according to one aspect of the present invention is an electrode assembly in which a core and an outer circumference are defined by winding a first electrode, a second electrode, and a separation membrane interposed between the first electrode and the second electrode around a winding shaft.

[0030] The first electrode may include a first active material portion coated with an active material layer along the winding direction, and a first plain portion that is not coated with an active material layer and is exposed to the outside of the separation membrane. The first plain portion may include segmented sections that are divided into a plurality of segmented sections that can be independently bent by a plurality of cutting grooves provided along the winding direction. The segmented sections include a plurality of segmented section groups arranged along the winding direction with intervals between groups, each segmented section group includes one or more segmented sections, and the plurality of segmented section groups may constitute one or more segmented section alignment portions on one side of the electrode assembly.

[0031] The segment alignment section includes p segments (where p is a natural number greater than 2) arranged radially, and the central point of the arc of the winding turn in which the p segment segments are located is C1 to C1, extending radially from the core side. p When defined as such, C1~C p At least a portion of these may not be located on a predetermined alignment line extending radially from the center of the core.

[0032] The aforementioned segment alignment sections number n, and the n segment alignment sections can be spaced apart along the circumferential direction of the electrode assembly.

[0033] The aforementioned n can range from 2 to 9.

[0034] n segment groups may be arranged in the same winding turn, and these n segment groups may be arranged at substantially equal intervals along the winding direction.

[0035] Above C1~C p More than 50% of the electrodes may be in a state where they are rotated in the winding direction of the electrode assembly with respect to the alignment line.

[0036] Above C1~C p More than 50% of the electrodes may be rotated in the opposite direction to the winding direction of the electrode assembly, with respect to the alignment line.

[0037] The n segment alignment sections can be arranged rotationally symmetrically with respect to the center of the core.

[0038] The rotational symmetry angle may be 40°, 45°, 60°, 72°, 90°, 120°, or 180°.

[0039] The n segment alignment sections can be arranged point-symmetrically with respect to the center of the core.

[0040] The n segment alignment sections may extend radially with respect to the center of the core.

[0041] The segment alignment section may have a geometric shape when viewed from the winding axis direction, consisting of an inner arc adjacent to the core, an outer arc adjacent to the outer circumference, and two lines connecting the ends of the arcs of the winding turns in which each segment group is located from the core side to the outer circumference side.

[0042] The aforementioned geometric shape may be a fan shape.

[0043] The two lines mentioned above may each extend in a nonlinear manner.

[0044] The electrode assembly may include a bent surface region formed by bending the p divided chip groups toward the core side.

[0045] The electrode assembly further includes a current collector welded to the bent surface region. When viewed from the winding axis direction of the electrode assembly, the arc of the winding turn where the p divided chip groups are located may intersect the welding line of the current collector and, optionally, a virtual line extending from the welding line with the same width.

[0046] The width of the welding line may be 1 mm or more.

[0047] When the arc of the winding turn is virtually rotated so that C1 to C of the arc of the winding turn is located on the alignment line, the arcs of the winding turns are arranged in a fan shape, and the maximum rotation angle θ of the end of the divided chip group included in the divided chip alignment portion with respect to the alignment line p When defined as the maximum value among the circumferential angle θ of the fan-shaped arc, the circumferential angle θ of the arc of the winding turn that intersects the welding line, and the circumferential angle of half of the arc of the winding turn that intersects the welding line, the following relational expression may be satisfied. max The circumferential angle θ of the fan-shaped arc design And the maximum value among the circumferential angles of half of the arc of the winding turn that intersects the welding line is defined as θ weld,max When defined as, the following relational expression may be satisfied. θ design >θ max +θ weld,max

[0048] The θ weld,max May be a value determined by the following mathematical formula. θ weld,max =(360°×0.5×d arc ) / (2πr) Here, d arc Is the maximum value of the length of the arc of the winding turn that intersects the welding line, and r is the radius of the arc of the corresponding winding turn based on the center of the core.

[0049] In one form, when the electrode thickness tolerance corresponding to the value obtained by adding the thickness tolerance of the first electrode and the thickness tolerance of the second electrode belongs to the range of ±1 μm, the θ design May be greater than 38°.

[0050] In other embodiments, when the thickness tolerance of the electrode corresponding to the sum of the thickness tolerances of the first electrode and the second electrode falls within the range of ±2 μm, the θ design This can be greater than 68°.

[0051] In another embodiment, when the thickness tolerance of the electrode corresponding to the sum of the thickness tolerances of the first electrode and the second electrode falls within the range of ±3 μm, the θ design It can be greater than 100°.

[0052] In another embodiment, when the thickness tolerance of the electrode corresponding to the sum of the thickness tolerances of the first electrode and the second electrode falls within the range of ±4 μm, the θ design This can be greater than 132°.

[0053] In another embodiment, when the thickness tolerance of the electrode corresponding to the sum of the thickness tolerances of the first electrode and the second electrode falls within the range of ±5 μm, the θ design This can be greater than 176°.

[0054] The electrode assembly may include an electrolyte-impregnated portion between adjacent segment alignment portions in the circumferential direction, where the end of the first active material portion in the winding axis direction is exposed from between the ends of radially adjacent separation membranes.

[0055] The number of electrolyte-impregnated portions is n, and the electrolyte-impregnated portions may extend radially from the center of the core.

[0056] The electrode assembly further includes an insulating layer that covers the boundary region between the first blank portion and the active material layer along the winding direction, and a gap may be provided between the insulating layer and the separation film.

[0057] The second electrode may include a second active material portion coated with an active material layer along the winding direction, and a second plain portion that is not coated with an active material layer and is exposed to the outside of the separation membrane so as to face the first plain portion along the winding axis. The second plain portion may include segmented sections divided into a plurality of independently bendable segmented sections by a plurality of cutting grooves provided along the winding direction. The segmented sections of the second plain portion include a plurality of segmented section groups arranged along the winding direction with inter-group spacing intervals, each segmented section group includes one or more segmented sections, and the plurality of such segmented section groups may constitute one or more segmented section alignment sections on one side of the electrode assembly. The segmented section alignment section of the second plain portion includes q (q is a natural number greater than 2) segmented section groups arranged radially, with the center point of the arc of the winding turn in which the q segmented section groups are located being measured radially from the core side C1~C q When defined as such, C1~C q At least a portion of these may not be located on a predetermined alignment line extending radially from the center of the core.

[0058] To achieve the above objectives, an electrode assembly according to another aspect of the present invention is an electrode assembly whose core and outer circumference are defined by winding a first electrode, a second electrode, and a separation membrane interposed between the first electrode and the second electrode 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 plain portion that is not coated with an active material layer and is exposed to the outside of the separation membrane, the first plain portion includes segment sections divided into a plurality of segment sections that can be independently bent by a plurality of cutting grooves provided along the winding direction, the segment sections include a plurality of segment group arrangements with inter-group spacing along the winding direction, each segment group includes one or more segment sections, the plurality of segment group arrangements constitute a plurality of segment alignment sections on one side of the electrode assembly, and the plurality of segment alignment sections are arranged rotationally symmetrically with respect to the center of the core.

[0059] Each of the aforementioned segment alignment sections may have an asymmetrical structure when viewed from the direction of the winding axis.

[0060] The segment alignment section includes p segments (where p is a natural number greater than 2) arranged radially, and the asymmetric structure is such that the central point of the arc of the winding turn in which the p segment segments are located is C1~C, extending radially from the core side. p When defined as such, C1~C p At least a portion of these may be structures that are not located on a predetermined alignment line extending radially from the center of the core.

[0061] To achieve the above objectives, a battery according to yet another aspect of the present invention includes: an electrode assembly having at least one of the above-described features; a battery housing having an open end and a closed end, housing the electrode assembly through the open end, and electrically connected to one of the first electrode and the second electrode to have a first polarity; a seal that seals the open end of the battery housing; and a terminal electrically connected to the other of the first electrode and the second electrode, with its surface exposed to the outside to have a second polarity.

[0062] The battery further includes a current collector electrically coupled to the bent surface region, and when viewed from the winding axis direction of the electrode assembly, the arc of the winding turn in which the p segment groups are located may intersect the weld line of the current collector, and optionally, a hypothetical line extending from the weld line.

[0063] A cavity is provided in the core of the electrode assembly, and the cavity can be opened to the outside without being blocked by the bent surface region.

[0064] The sealing body includes a cap plate that seals the open end of the battery housing and a gasket that wraps around the periphery of the cap plate and is crimped to the open end of the battery housing, and the terminal having the second polarity may be the cap plate.

[0065] The battery further includes a current collector electrically connected to the blank portion of the second electrode having the first polarity, with at least a portion of its periphery bonded to the side wall of the battery housing, the seal includes a non-polarized cap plate and a gasket that wraps around the periphery of the cap plate and is crimped to the open end of the battery housing, the battery housing may include a rivet terminal electrically connected to the first electrode and having the second polarity, which is insulatedly mounted in a through hole formed in the center of the closed end.

[0066] The technical problem of the present invention is solved by a battery pack containing multiple of the above-mentioned batteries.

[0067] Preferably, the battery may have a height-to-diameter ratio greater than 0.4.

[0068] Preferably, the form factor of the battery may be 46110, 4875, 48110, 4880, or 4680.

[0069] Preferably, the resistance of the battery may be 4 mΩ or less.

[0070] The technical challenges of the present invention can also be achieved by an automobile including the battery pack described above. [Effects of the Invention]

[0071] According to one aspect of the present invention, the internal resistance of the battery can be reduced and the energy density increased by using the plain portions protruding from the upper and lower sides of the electrode assembly as electrode tabs.

[0072] Furthermore, according to one aspect of the present invention, the impregnation characteristics of the electrode assembly can be improved by arranging a plurality of subsections radially in a localized region.

[0073] Furthermore, according to one aspect of the present invention, when multiple subsections are arranged radially in a local region, the welding line of the current collector can be stably maintained even when rotated clockwise or counterclockwise due to the thickness tolerance of the electrodes.

[0074] Furthermore, according to one aspect of the present invention, by improving the structure of the plain portion of the electrode assembly, it is possible to prevent the plain portion from tearing when bent, and to sufficiently increase the number of overlapping layers of the plain portion to improve the welding strength of the current collector.

[0075] Furthermore, according to one aspect of the present invention, by applying a segmentation structure to the plain portion of the electrode and optimizing the dimensions of the segmentation segments (width, height, and spacing pitch) to sufficiently increase the number of stacked segmentation segments in the area used as the welding target area, the physical properties of the area to which the current collector is welded can be improved.

[0076] Furthermore, according to one aspect of the present invention, by applying a structure in which a current collector is welded over a wide area to a bent surface region formed by bending a segment, it is possible to provide an electrode assembly with improved energy density and reduced resistance.

[0077] Furthermore, according to one aspect of the present invention, a cylindrical battery with an improved design that allows electrical wiring to be performed on the top can be provided.

[0078] Furthermore, according to one aspect of the present invention, by improving the structure of the plain portion adjacent to the core of the electrode assembly, it is possible to prevent the cavity in the core of the electrode assembly from becoming blocked when the plain portion is bent, thereby facilitating the electrolyte injection process and the welding process between the battery housing (or terminals) and the current collector.

[0079] Furthermore, according to one aspect of the present invention, it is possible to provide a cylindrical battery having a structure with low internal resistance, prevention of internal short circuits, and improved welding strength between the current collector and the blank portion, a battery pack including the cylindrical battery, and an automobile.

[0080] 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 cylindrical battery, and an automobile.

[0081] The present invention also provides a variety of other effects, which will be described later with reference to embodiments. However, effects that can be easily inferred by an ordinary person will not be described.

[0082] The following drawings accompanying this specification illustrate preferred embodiments of the invention and, together with the detailed description of the invention, are intended to further illustrate the technical idea of ​​the invention; therefore, the invention shall not be construed as being limited solely to what is shown in the drawings. [Brief explanation of the drawing]

[0083] [Figure 1] This is a plan view showing the structure of electrodes used in the manufacture of conventional tablet cylindrical batteries. [Figure 2] This diagram shows the electrode winding process for a conventional cylindrical tablet battery. [Figure 3] This diagram illustrates the process of welding a current collector to the bent surface area of ​​the plain section in a conventional tabletless cylindrical battery. [Figure 4] This is a plan view showing the structure of an electrode according to one embodiment of the present invention. [Figure 5] This figure shows the definitions of the width, height, and spacing pitch of the section according to an embodiment of the present invention. [Figure 6a] This figure shows, with respect to the center of the core of the electrode assembly, the arc formed by the lower end of the segment that defines the width of the segment when the electrode is wound according to an embodiment of the present invention. [Figure 6b] This figure schematically shows the relationship between the heights h1, h2, h3, h4 of the segmentation section, the core radius rc, and the radii r1, r2, r3, r4 of the winding turns where the segmentation section begins to appear, according to an embodiment of the present invention. [Figure 6c]This is a conceptual diagram for determining the maximum value hmax of the segmental intercept height H in the segmental intercept height variable interval. [Figure 6d] This is a schematic diagram illustrating the formula for determining the lower interior angle θ of the segment. [Figure 7a] This is a plan view showing another electrode structure according to an embodiment of the present invention. [Figure 7b] This is a plan view showing yet another electrode structure according to an embodiment of the present invention, in which subsection groups located in the same winding turn are arranged at equal intervals. [Figure 7c] This is a top view of an electrode assembly manufactured by winding the electrode shown in Figure 7a, when the electrode thickness tolerance according to an embodiment of the present invention is 0 (zero). [Figure 7d] This is a top view of an electrode assembly manufactured by winding the electrode shown in Figure 7a, when the electrode thickness tolerance according to an embodiment of the present invention is positive. [Figure 7e] This is a top view of an electrode assembly manufactured by winding the electrode shown in Figure 7a, when the electrode thickness tolerance according to an embodiment of the present invention is negative. [Figure 7f] Figure 7a shows a top view of an electrode assembly manufactured by winding the electrode shown in the embodiment of the present invention, where the electrode thickness tolerance is positive and the electrode thickness tolerance changes along the winding direction. [Figure 7g] Figure 7f is a top view showing the arrangement structure of the weld lines when a current collector is welded to the bent surface region with the segment group included in the segment alignment section shown in Figure 7f bent toward the core side. [Figure 7h] This is a top view showing the state in which the segment group included in the segment alignment section has rotated clockwise by the maximum angle when the electrode according to an embodiment of the present invention has a positive thickness tolerance. [Figure 7i] This is a top view showing the state in which the segment group included in the segment alignment section has rotated counterclockwise by the maximum angle when the electrode according to an embodiment of the present invention has a negative thickness tolerance. [Figure 7j] This figure illustrates the concept of expanding the inscribed angle of the segment alignment portion, taking into account the width of the weld line, according to an embodiment of the present invention. [Figure 8] This figure is for deriving the mathematical relationships that an electrode assembly to which an embodiment of the present invention is applied satisfies. [Figure 9] This figure shows the segment structure in various modified forms according to the present invention. [Figure 10] This is a schematic diagram showing a cross-section of a bent surface region formed when a section is bent toward the core side of the electrode assembly according to an embodiment of the present invention. [Figure 11a] This graph shows the results of counting the number of stacked segments along the radial direction in the bent surface region of the positive electrode formed on the upper part of the electrode assemblies according to Examples 1-1 to 1-7 and the comparative example. [Figure 11b] This graph shows the results of counting the number of stacked segments measured along the radial direction in the bent surface region of the positive electrode formed on the upper part of the electrode assemblies 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 11c] This graph shows the results of counting the number of stacked segments measured along the radial direction in the bent surface region of the positive electrode formed on the upper part of the electrode assembly according to Examples 6-1 to 6-6 and Examples 7-1 to 7-6. [Figure 12] This is a top view of an electrode assembly according to an embodiment of the present invention, showing a uniform layer number section b1 and a decreasing layer number section b2 in the folded surface region of a segment. [Figure 13] This 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 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. [Figure 14] This 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 as 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. [Figure 15]This 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 as 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. [Figure 16] This 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 as 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. [Figure 17] This is a cross-sectional view of a cylindrical battery according to one embodiment of the present invention, obtained by cutting along the Y-axis direction so as to pass through the bent surface region of the segment included in the segment alignment section. [Figure 18] This is a cross-sectional view of a cylindrical battery according to another embodiment of the present invention, obtained by cutting along the Y-axis direction so as to pass through the bent surface region of the segment included in the segment alignment section. [Figure 19] This is a cross-sectional view of a cylindrical battery according to yet another embodiment of the present invention, obtained by cutting along the Y-axis direction so as to pass through the bent surface region of the segment included in the segment alignment section. [Figure 20] This is a cross-sectional view of a cylindrical battery according to yet another embodiment of the present invention, obtained by cutting along the Y-axis direction so as to pass through the bent surface region of the segment included in the segment alignment section. [Figure 21] This is a top view showing the structure of the first current collector according to an embodiment of the present invention. [Figure 22] This is a perspective view showing the structure of the second current collector according to an embodiment of the present invention. [Figure 23] This is a top view showing multiple cylindrical batteries electrically connected. [Figure 24] This is a magnified view of a portion of Figure 23. [Figure 25] This diagram schematically shows the configuration of a battery pack according to one embodiment of the present invention. [Figure 26] This diagram schematically shows an automobile including a battery pack according to one embodiment of the present invention. [Modes for carrying out the invention]

[0084] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. Prior to this, terms and words used herein and in the claims shall not be interpreted in their usual and dictionary sense, but rather in a sense and concept that corresponds to the technical idea of ​​the present invention, in accordance with the principle that the inventor himself may appropriately define the concept of terms in order to best describe the invention.

[0085] Therefore, the embodiments described herein and the configurations shown in the drawings represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the invention. It should be understood that there are various equivalents and modifications that can be substituted for these at the time of filing this application.

[0086] Furthermore, to aid in understanding the invention, the accompanying drawings are not shown to actual scale, and the dimensions of some components may be exaggerated. Also, the same component in different embodiments may be assigned the same reference numeral.

[0087] 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 this industry, for example, deviations of 5% or less. Furthermore, when a parameter is said to be uniform in a given domain, it means that it is uniform in that domain from an average perspective.

[0088] Furthermore, while terms like "first," "second," etc., are used to indicate various components, these terms are not intended to limit the components. These terms are simply used to distinguish one component from others, and unless otherwise specified, the first component can also be the second component.

[0089] Throughout the specification, unless otherwise specified, each component may be singular or plural.

[0090] To say that any component is placed "above (or below)" or "above (or below)" a component means not only that the component is placed in contact with the upper (or lower) surface of the component, but also that other components may be interposed between the component and any component placed above (or below) it.

[0091] Furthermore, when one component is described as being "connected," "joined," or "linked" to another component, this includes not only cases where the components are directly connected to or linked to each other, but also cases where other components are "interposed" between each component, or where each component is "connected," "joined," or "linked" through other components.

[0092] Throughout this specification, "A and / or B" means A, B, or A and B unless otherwise specified, and "C-D" means C to D unless otherwise specified.

[0093] In this specification, for the sake of explanation, 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 periphery direction (X-axis). The direction approaching or moving away from the winding shaft is referred to as the radial direction. Of these, the direction approaching the winding shaft is referred to as the centripetal direction, and the direction moving away from the winding shaft is referred to as the centrifugal direction.

[0094] First, an electrode assembly according to one embodiment of the present invention will be described. The electrode assembly may be a jelly roll type electrode assembly having a structure in which a sheet-like first electrode, a second electrode, and a separation membrane interposed between the first electrode and the second electrode are wound in one direction. However, the present invention is not limited by the type of electrode assembly.

[0095] Preferably, at least one of the first electrode and the second electrode includes a plain portion at the long edge in the winding direction where the active material is not coated. At least a portion of the plain portion is used as an electrode tab. The plain portion includes a core-side plain portion adjacent to the core of the electrode assembly, an outer-circumferential plain portion adjacent to the outer surface of the electrode assembly, and an intermediate plain portion interposed between the core-side plain portion and the outer-circumferential plain portion.

[0096] Preferably, at least one of the plain core portion and the plain outer periphery portion is relatively lower in height than the intermediate plain portion.

[0097] Figure 4 is a plan view showing the structure of an electrode 60 according to one embodiment of the present invention.

[0098] Referring to Figure 4, in one embodiment, the electrode 60 includes a current collector 41 made of metal foil and an active material layer 42. The metal foil may be a conductive metal, such as aluminum or copper, and is appropriately selected according to the polarity of the electrode 60. The active material layer 42 is formed on at least one surface of the current collector 41. The active material layer 42 is formed along the winding direction (X-axis). The electrode 60 includes a plain portion 43 at the long side end in the winding direction (X-axis). The plain portion 43 is a part of the current collector 41 that is not coated with the active material. The region of the current collector 41 on which the active material layer 42 is formed may be called the active material portion.

[0099] In electrode 60, the width of the active material portion in the short-side direction of the current collector 41 can be 50 mm to 120 mm, and the length of the active material portion in the long-side direction of the current collector 41 can be 3 m to 5 m. Therefore, the ratio of the short side to the long side of the active material portion can be 1.0% to 4.0%.

[0100] Preferably, in the electrode 60, the width of the active material portion in the short-side direction of the current collector 41 may be 60 mm to 70 mm, and the length of the active material portion in the long-side direction of the current collector 41 may be 3 m to 5 m. Therefore, the ratio of the short side to the long side of the active material portion may be 1.2% to 2.3%.

[0101] The ratio of the short side to the long side of the active material portion is significantly smaller than the 6%–11% ratio of the short side to the long side of the active material portion of the electrode used in cylindrical batteries with a 1865 or 2170 form factor.

[0102] Preferably, an insulating coating layer 44 may be formed at the boundary between the active material layer 42 and the blank portion 43. The insulating coating layer 44 is formed so that at least a portion of it overlaps the boundary between the active material layer 42 and the blank portion 43. The insulating coating layer 44 prevents short circuits between two electrodes of opposite polarity that are facing each other with a separator film in between. The insulating coating layer 44 may cover the boundary portion between the active material layer 42 and the blank portion 43 with a width of 0.3 mm to 5 mm. The width of the insulating coating layer 44 may vary along the winding direction of the electrode 60. The insulating coating layer 44 contains a polymer resin and may contain inorganic fillers such as SiO2 and Al2O3. The portion of the current collector 41 covered by the insulating coating layer 44 may be considered a blank portion because it is not a region coated with the active material layer.

[0103] The plain portion 43 includes a core-side plain portion B1 adjacent to the core side of the electrode assembly, an outer-circumferential plain portion B3 adjacent to the outer-circumferential side of the electrode assembly, and an intermediate plain portion B2 interposed between the core-side plain portion B1 and the outer-circumferential plain portion B3.

[0104] The plain core portion B1, the plain outer peripheral portion B3, and the plain intermediate portion B2 can be defined as the plain region adjacent to the core, the plain region adjacent to the outer peripheral, and the plain region excluding these areas, respectively, when the electrode 60 is wound up as a jelly roll-type electrode assembly.

[0105] Hereinafter, the plain core section B1, the plain outer perimeter section B3, and the plain intermediate section B2 will be referred to as the first section, the second section, and the third section, respectively.

[0106] For example, the first portion B1 may be a plain area of ​​the electrode region including the innermost winding turn, and the second portion B3 may be a plain area of ​​the electrode region including the outermost winding turn. The winding turns can be counted relative to the core-side end of the electrode assembly.

[0107] As another example, the B1 / B2 boundary can be appropriately defined at a point where the height (or variation pattern) of the plain area substantially changes from the core side to the outer circumference of the electrode assembly, or at a predetermined percentage point relative to the radius of the electrode assembly (e.g., 5%, 10%, 15% of the radius).

[0108] The B2 / B3 boundary can be defined at the point where the height (or variation pattern) of the plain area substantially changes from the outer circumference of the electrode assembly toward the core, or at a predetermined percentage point relative to the radius of the electrode assembly (e.g., 85%, 90%, 95% of the radius). Once the B1 / B2 boundary and the B2 / B3 boundary are identified, the third part B2 can be automatically identified.

[0109] If only the B1 / B2 boundary is specified, the B2 / B3 boundary can be appropriately selected at a point near the outer circumference of the electrode assembly. For example, the second part can be defined as the plain area of ​​the electrode region constituting the outermost winding turn. On the other hand, if only the B2 / B3 boundary is specified, the B1 / B2 boundary can be appropriately selected at a point near the core side of the electrode assembly. For example, the first part B1 can be defined as the plain area of ​​the electrode region constituting the innermost winding turn.

[0110] This does not rule out the possibility of other structures intervening between the first part B1 and the third part B2. Nor does it rule out the possibility of other structures intervening between the third part B2 and the second part B3.

[0111] The height of the plain section 43 is not constant and varies relative to the winding direction (X-axis). That is, the height of the second section B3 (length in the Y-axis direction) is 0 or greater and is relatively lower than the first section B1 and the third section B2. Here, the height of each section may be the average height or the maximum height, and so on. In the winding direction, the length of the third section B2 is even longer than the first section B1 and the second section B3.

[0112] The electrode 60 has a height of 0 or greater for the first part B1 and the second part B3, and is relatively lower than the third part B2. Also, the heights of the first part B1 and the second part B3 may be the same or different.

[0113] Width d of Part B1 B1 The design applies the condition that when the plain portion of the third part B2 is folded towards the core, it does not block the core of the electrode assembly. The core refers to the cavity located at the winding center of the electrode assembly.

[0114] For example, the width d of the first part B1. B1 This can increase in proportion to the fold length of the plain area closest to the core.

[0115] Preferably, the width d of the first portion B1. B1 The radial width of the winding turn formed by the first portion B1 may be set to be greater than or equal to the fold length of the plain area most adjacent to the core. In the modified example, the width d of the first portion B1 B1 This can be set such that the value obtained by subtracting the radial width of the winding turn formed by the first part B1 from the fold length of the plain area most adjacent to the core is less than 0 or less than 10% of the core radius.

[0116] In a specific example, if electrode 60 is used to manufacture an electrode assembly for a cylindrical battery of form factor 4680, the width d of the first part B1 is B1 This can be set to 180mm to 350mm depending on the diameter of the electrode assembly core and the bending length of the plain area most adjacent to the core.

[0117] The blank portion of the third part B2 may include at least a portion of a section containing multiple subsections 61. The height of the multiple subsections 61 may increase gradually from the core side to the outer periphery side. Alternatively, the height of the multiple subsections 61 may be maintained at the same level from the core side to the outer periphery side. The multiple subsections 61 have a geometric shape in which the width decreases from the bottom to the top. Preferably, the geometric shape is a trapezoid. As will be described later, the shape of the geometric shape can be varied in various ways, such as a quadrilateral or parallelogram.

[0118] The section 61 may be notched with a laser. The section 61 may be formed by known metal foil cutting processes such as ultrasonic cutting or punching.

[0119] When bending the plain section 43, it is preferable to provide a predetermined gap between the bottom of the cutting groove between the segment pieces 61 (G in Figure 5) and the active material layer 42 in order to prevent damage to the active material layer 42 and / or the insulating coating layer 44. This is because stress is concentrated near the bottom of the cutting groove 63 when the plain section 43 is bent. The gap may vary along the winding direction of the electrode 60. The gap is preferably 0.2 mm to 4 mm, more preferably 1.5 mm to 2.5 mm. By adjusting the gap to the above numerical range, it is possible to prevent damage to the active material layer 42 and / or the insulating coating layer 44 near the bottom of the cutting groove 63 due to stress generated when bending the plain section 43. The gap can also prevent damage to the active material layer 42 and / or the insulating coating layer 44 due to notches or tolerances during cutting of the segment pieces 61. In one direction parallel to the winding direction, the gap may be substantially the same or vary. In the latter case, the gap between multiple segments can vary individually, in groups, or in groups of two or more along one direction parallel to the winding direction. The bottom of the cutting groove 63 and the insulating coating layer 44 can be separated by 0.5 mm to 2.0 mm. In one direction parallel to the winding direction, the separation distance between the bottom of the cutting groove 63 and the insulating coating layer 44 may be approximately the same or vary. In the latter case, the separation distance between multiple segments can vary individually, in groups, or in groups of two or more along one direction parallel to the winding direction. When the electrode 60 is wound, the end of the insulating coating layer 44 in the direction of the winding axis (Y axis) can be located in the range of -2 mm to 2 mm along the winding axis direction with respect to the end of the separation membrane. The insulating coating layer 44 can prevent short circuits between two electrodes of opposite polarity facing each other with the separation membrane in between, and can support the bending point when the segment 61 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 separation film. 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 direction of the winding axis (Y axis) is located above the bottom of the cutting groove 63.In one example, the end of the insulating coating layer 44 in the winding axis direction may be located within a range of -2 mm to +2 mm relative to the bottom of the cutting groove 63. The thickness of the insulating coating layer 44 may be thinner than that of the active material layer. In this case, a gap may be formed between the surface of the insulating coating layer 44 and the separation film.

[0120] In one embodiment, the multiple subsections 61 may form multiple subsection groups from the core side to the outer circumference side. At least one of the width, height, and spacing pitch of subsections belonging to the same subsection group may be substantially the same. Preferably, the width, height, and spacing pitch of subsections belonging to the same subsection group may be the same as each other.

[0121] Preferably, the width and height of sections belonging to the same section group may be substantially the same.

[0122] In other forms, the segments may be arranged in groups or in groups of two or more groups, with the spacing pitch gradually or stepwise increasing from the core side to the outer periphery side, or vice versa.

[0123] In yet another form, the segments may, in groups or in groups of two or more, have a separation pitch that gradually or stepwise increases from the core side to the outer periphery side, then gradually or stepwise decreases, or vice versa.

[0124] In yet another embodiment, the gap between the bottom of the cutting groove 63 and the insulating coating layer 44 or active material layer 42 may increase gradually or stepwise from the core side to the outer circumference, or vice versa.

[0125] In yet another embodiment, the gap between the bottom of the cutting groove 63 and the insulating coating layer 44 or active material layer 42 may increase or decrease gradually or stepwise from the core side to the outer circumference, or vice versa.

[0126] Figure 5 shows the definitions of the width D, height H, and separation pitch P of the trapezoidal segment 61.

[0127] Referring to Figure 5, the width D, height H, and separation pitch P of the segment 61 are designed to prevent the plain section 43 from tearing near the bending point during bending and to ensure sufficient welding strength, while also preventing abnormal deformation of the plain section 43 by sufficiently increasing the number of overlapping layers of the plain section 43.

[0128] The folding of the segment 61 is performed along or above the line G passing through the bottom of the cutting groove 63. The cutting groove 63 allows for smooth and easy folding of the segment 61 in the radial direction of the electrode assembly.

[0129] The width D of the segment 61 is defined by the distance between two points where two straight lines extending from the side edges 63b of the segment 61 intersect with a straight line extending from the bottom 63a of the cutting groove 63. The height H of the segment 61 is defined by the shortest distance between the uppermost edge of the segment 61 and the straight line extending from the bottom 63a of the cutting groove 63. The spacing pitch P of the segment 61 is defined by the distance between two points where a straight line extending from the bottom 63a of the cutting groove 63 intersects with two straight lines extending from the two side edges 63b connected to the bottom 63a. When the side edges 63b and / or the bottom 63a are curves, the straight lines can be replaced by tangents extending from the intersection of the side edges 63b and the bottom 63a to the side edges 63b and / or the bottom 63a.

[0130] Preferably, the width D of the segment 61 is 1 mm or more. If D is less than 1 mm, when the segment 61 is bent toward the core, the segment 61 may not overlap to a sufficient extent to ensure sufficient welding strength, or a gap may be created.

[0131] Preferably, the width D of the segment 61 can be adaptively adjusted according to the radius of the winding turn in which the segment 61 is located, so that when the segment 61 is bent toward the core side of the electrode assembly, the segment 61 easily overlaps radially.

[0132] Figure 6a shows the lower end of the segment 61 (line segment D in Figure 5) where the width D of the segment 61 is defined when the electrode 60 is wound according to an embodiment of the present invention. ab This diagram shows the arcs A1 and A2 formed by the electrode assembly, with respect to the center O of the core.

[0133] Referring to Figure 6a, the arc A1A2 has a length corresponding to the width D of the segment 61 and has an inscribed angle Φ with respect to the center of the core of the electrode assembly. The inscribed angle Φ can be defined as the angle between two line segments connecting the ends of the arc A1A2 and the center O of the core, on a plane perpendicular to the winding axis passing through the arc A1A2.

[0134] When the lengths of the arcs A1 and A2 of the segment 61 are the same, the inscribed angle Φ decreases as the radius r of the winding turn in which the segment 61 is located increases. Conversely, when the inscribed angle Φ of the segment 61 is the same, the lengths of the arcs A1 and A2 increase proportionally as the radius r of the winding turn in which the segment 61 is located increases.

[0135] The inscribed angle Φ affects the bending quality of the segment 61. In the drawing, solid arrows indicate the direction of the force applied to bend the segment 61, and dotted arrows indicate the direction in which the segment 61 is bent. The bending direction is toward the center O of the core.

[0136] The inscribed angle Φ of the segment 61 may be 45° or less, preferably 30° or less, depending on the radius r of the winding turn in which the segment 61 is located, in order to improve the uniformity of bending and prevent the occurrence of cracks.

[0137] In one embodiment, the inscribed angle Φ of the segmentation section 61 may gradually or stepwise increase or decrease along the radial direction of the electrode assembly within the above numerical range. In another embodiment, the inscribed angle Φ of the segmentation section 61 may gradually or stepwise increase and then gradually or stepwise decrease along the radial direction of the electrode assembly within the above numerical range, and vice versa is also possible. In yet another embodiment, the inscribed angle Φ of the segmentation section 61 may be substantially the same along the radial direction of the electrode assembly within the above numerical range.

[0138] Experiments have shown that when the inscribed angle Φ of the segment 61 exceeds 45°, the folding pattern of the segment 61 becomes uneven. The difference in force applied to the central and side portions of the segment 61 becomes large, resulting in uneven pressure on the segment 61 in the circumferential direction. Furthermore, if the pressing force is increased to ensure folding uniformity, cracks may occur in the plain area 43 near the cutting groove 63.

[0139] In one example, the inscribed angles Φ of the segmental sections 61 contained within the electrode 60 are substantially identical, and the width of the segmental section 61 may increase proportionally as the radius r of the winding turn in which the segmental section 61 is located increases. Substantially identical means either completely identical or with a deviation of less than 5%.

[0140] For example, if the radius of the electrode assembly is 22 mm, the radius of the core is 4 mm, and the segment 61 is positioned from a winding turn located at a radius of 7 mm, and the inscribed angle Φ of the segment 61 is constant at 28.6°, then the width D of the segment 61 can increase proportionally with respect to the radius r of the winding turn in which the segment 61 is located, as shown in Table 1 below. That is, the width of the segment 61 can increase by 0.5 mm at substantially the same rate for every 1 mm increase in the radius r of the winding turn.

[0141] [Table 1]

[0142] Preferably, the width D(r) of the segment 61 located in a winding turn with radius r relative to the center O of the electrode assembly core can be determined within a range that satisfies the following formula 1.

[0143] [Formula 1] 1≦D(r)≦(2×π×r / 360°)×45° Preferably, each of the multiple segment sections 61 may have a winding width D(r) that increases gradually or in steps as the radius r of the winding turn in which the segment section 61 is located increases, relative to the center of the core of the electrode assembly, or vice versa.

[0144] In other embodiments, each of the multiple subsections 61 may have a winding width D(r) that increases gradually or in steps in the winding direction, ranging from 1 mm to 11 mm, as the radius r of the winding turn in which the subsection 61 is located increases with respect to the center of the core of the electrode assembly, or vice versa.

[0145] In yet another embodiment, each of the multiple subsections 61 may have a winding width D(r) that gradually or stepwise increases and then gradually or stepwise decreases as the radius r of the winding turn in which the subsection 61 is located increases with respect to the center of the core of the electrode assembly, or vice versa.

[0146] In yet another embodiment, each of the multiple subsections 61 may have a winding width D(r) that gradually or stepwise increases and then gradually or stepwise decreases in the range of 1 mm to 11 mm as the radius r of the winding turn in which the subsection 61 is located increases with respect to the center of the electrode assembly core, or vice versa.

[0147] In other embodiments, the rate at which the width D(r) of the segment 61 changes as the radius r of the winding turn in which the segment 61 is located increases may be the same or different.

[0148] In other configurations, the rate at which the width D(r) of the segment 61 changes in the range of 1 mm to 11 mm as the radius r of the winding turn in which the segment 61 is located increases may be the same or different.

[0149] Referring further to Figure 5, the height H of the segment 61 may be 2 mm or more. If D2 is less than 2 mm, when the segment 61 is bent toward the core, the segment 61 may not overlap to a sufficient extent to ensure sufficient welding strength, or a gap may be created.

[0150] The height H of the segment 61 can be determined by applying the condition that the segment 61 does not block the core when it is folded toward the core. Preferably, the height H of the segment 61 can be adjusted so that 90% or more of the core's diameter is open to the outside.

[0151] Preferably, the height H of the segment 61 can gradually increase from the core side to the outer circumference depending on the radius of the winding turn and the radius of the core in which the segment 61 is located.

[0152] In one example, the height H of the segment 61 increases from h1 to h as the radius of the winding turn increases. N As it increases stepwise over N steps, the k-th height h of the segment 61 k (k is a natural number from 1 to N), height h k The starting radius of the winding turn is r, which includes a segment 61 having a segment 61. k , the radius of the core is r c When this is the case, the heights h1 to h of the segment 61 should satisfy the following equation 2. N This may be decided.

[0153] [Formula 2] 2mm≦h k ≤r k -α×r c (Preferably, α is 0.90 to 1) Height h of segment 61 k If equation 2 is satisfied, then even if the segment 61 is bent toward the core, the core can be open to the outside by more than 90% of its diameter.

[0154] For example, if the overall winding turn radius of the electrode assembly is 22 mm, the height of the segment 61 starts at 3 mm, and for every 1 mm increase in the radius of the winding turn containing the segment 61, the height of the segment 61 increases sequentially to 3 mm, 4 mm, 5 mm, and 6 mm, and the height can be maintained substantially the same at 6 mm in the remaining winding turns. In other words, the radial width of the variable height section of the segment 61 within the radius of the overall winding turn is 3 mm, and the remaining radial section corresponds to the uniform height section.

[0155] In this case, the radius r of the core of the electrode assembly c The starting radii r1, r2, r3, and r3 of the winding turns, which include segment 61 having heights of 3 mm, 4 mm, 5 mm, and 6 mm respectively, are as shown in Table 2 below, when α is 1 and the equality condition is applied in the inequality on the right.

[0156] [Table 2]

[0157] When the segment 61 is positioned at the radial position shown in Table 2, the core is not blocked by the segment 61 even if the segment 61 is bent toward the core. On the other hand, r1, r2, r3, and r3 shown in Table 2 can be shifted toward the core depending on the α value. In one example, when α is 0.90, r1, r2, r3, and r3 can be shifted toward the core by 10% of the core radius. In this case, when the segment 61 is bent toward the core, 10% of the core radius is blocked by the segment 61. r1, r2, r3, and r3 shown in Table 2 are limit values ​​for the starting position of the segment 61. Therefore, the position of the segment 61 can be shifted by a predetermined distance toward the outer circumference from the radius shown in Table 2. Figure 6b shows the heights h1, h2, h3, h4 of the segment 61 and the core radius r c This diagram schematically shows the relationship between the radii r1, r2, r3, and r3 of the winding turn where the segment 61 begins to appear.

[0158] Referring to Table 2 and Figure 6b, for example, the radius r of core C cWhen it is 3 m, the starting radii r1, r2, r3, and r3 of the winding turns including the segmented slices 61 having heights of 3 mm (h1), 4 mm (h2), 5 mm (h3), and 6 mm (h4) can be 6 mm, 7 mm, 8 mm, and 9 mm respectively, and the height of the segmented slice 61 can be maintained at 6 mm from a radius of 9 mm to the last winding turn. Also, the winding turns having a radius smaller than 6 mm (r1) may not include the segmented slice 61. In such an example, since the segmented slice 61 with a height of 3 mm (h1) closest to the core C is located from the winding turn with a radius of 6 mm, even if the corresponding segmented slice 61 is bent toward the core C side, it only covers the radius range of 3 mm to 6 mm and does not substantially block the core C. Depending on the α value of Equation 2, the position of the segmented slice 61 can be shifted toward the core C within 10% of the core radius r c and can be shifted toward the core C side within 10% of the core radius r.

[0159] In other forms, the height of the segmented slice 61 can increase at the same or different ratios as the starting radius r of the winding turn where the segmented slice 61 is located increases with reference to the center of the core of the electrode assembly.

[0160] Preferably, the height H of the segmented slice 61 satisfies Equation 2 and the maximum height of the segmented slice 61 can be limited.

[0161] FIG. 6c is a conceptual diagram for determining the maximum value h with respect to the height H of the segmented slice 61 in the variable height range of the segmented slice 61. max is a conceptual diagram for determining the maximum value h with respect to the height H of the segmented slice 61 in the variable height range of the segmented slice 61.

[0162] Referring to FIG. 6c, in the winding structure of the electrode assembly, the electrode E1 including the segmented slice 61 faces the electrode E2 of the opposite polarity with the separation membrane S intervening in the radial direction. Active material layers E 1,active are coated on both sides of the electrode E1, and active material layers E 2,active are also coated on both sides of the electrode E2. For electrical insulation, the end S end of the separation membrane S is insulated from the end E 2,end of the electrode E2 by an insulation gap W gapIt may extend further outward by a length corresponding to that. Also, the end of electrode E1 does not extend further outward than the end of electrode E2 for electrical insulation. Therefore, there is an insulating gap W at the lower end of the plain section 43. gap A corresponding section must be secured. Also, when electrodes E1 and E2 and the separation membrane S are wound up, the end S of the separation membrane S end This causes meandering. Therefore, for the section 61 to be exposed to the outside of the separation membrane S, the section W corresponding to the minimum meandering margin of the separation membrane S must be exposed. margin,min The blank section 43 must be allocated to it. Also, in order to cut the segment 61, a minimum cutting scrap margin W must be placed at the end of the current collector foil. scrap,min A value must be assigned. Therefore, the maximum height h of the subsection 61 in the height-variable section of the subsection 61. max This can be determined by the following equation 3. In equation 3, W foil This corresponds to the width of the current collector foil before it is cut.

[0163] [Formula 3] h max =W foil -W scrap,min -W margin,min -W gap Preferably, the insulation gap W gap The insulation gap W can be 0.2 mm to 6 mm when the first electrode is the positive electrode. gap This can be 0.1 mm to 2 mm when the first electrode is the negative electrode.

[0164] Preferably, the minimum cutting scrap margin W scrap,min This can be 1.5mm to 8mm. Minimum cutting scrap margin W scrap,min This does not have to be assigned by the process of forming the segment 61. For example, the cutting groove 63 can be formed so that the upper edge of the segment 61 coincides with the upper edge of the current collector wheel. In this case, in equation 3, W scrap,min It can be 0.

[0165] Preferably, the minimum meandering margin W of the separation membrane. margin,min It can be 0-1 mm.

[0166] As an example, the minimum cutting scrap margin W scrap,min The minimum meandering margin W of the separation membrane S is 1.5 mm. margin,min This can be 0.5 mm. Under these conditions, the width W of the current collector wheel before forming the segment 61. foil The insulation gap is 8mm to 12mm, and W gap When the dimensions are 0.6 mm, 0.8 mm, and 1.0 mm, the maximum height h of the segment 61 can be calculated using formula 3. max The results of the calculation are shown in Table 3 below.

[0167] [Table 3]

[0168] Referring to Table 3, the maximum height h of the subsection 61 in the height-variable section of the subsection 61 max The distance can be set to 10 mm. Therefore, the height of the segment 61 in the height variable section of the segment 61 satisfies Equation 2 and can be increased stepwise or gradually along the radial direction of the electrode assembly in the 2 mm to 10 mm range. Referring further to Figure 5, the separation pitch P of the segment 61 can be adjusted from 0.05 to 1.0 mm. If the separation pitch P is less than 0.05 mm, when the electrode 60 runs during the winding process, stress may cause cracks in the plain section 43 near the bottom of the cutting groove 63. On the other hand, if the separation pitch P exceeds 1 mm, when the segment 61 is bent, the segment 61 may not overlap to a degree that allows sufficient welding strength to be ensured, or gaps may be created.

[0169] On the other hand, if the current collector 41 of the electrode 60 is made of aluminum, it is more preferable to set the separation pitch P to 0.5 mm or more. When the separation pitch P is 0.5 mm or more, even if the electrode 60 runs at a speed of 100 mm / sec or more under a tension of 300 gf or more during the winding process, it is possible to prevent cracks from occurring at the bottom of the cutting groove 63.

[0170] According to experimental results, when the current collector 41 of the electrode 60 is 15 μm thick aluminum foil and the separation pitch P is 0.5 mm or more, no cracks occur at the bottom of the cutting groove 63 when the electrode 60 is running under the above-mentioned running conditions.

[0171] As shown in Figure 5, a cutting groove 63 is interposed between two adjacent segment pieces 61 in the winding direction (X-axis). The cutting groove 63 corresponds to the space created when the plain portion 43 is removed. Preferably, the corner portions at both ends of the bottom of the cutting groove 63 are rounded. That is, the cutting groove 63 includes a substantially flat bottom portion 63a and a rounded portion 63c. The rounded portion 63c connects the bottom portion 63a to the side edge 63b of the segment piece 61. In a modified example, the bottom portion 63a of the cutting groove 63 can be replaced with an arc shape. In this case, the side edges 63b of the segment pieces 61 can be smoothly connected by the arc shape of the bottom portion 63a.

[0172] The radius of curvature of the rounded portion 63c may be greater than 0 and less than or equal to 0.5 mm, preferably greater than 0 and less than or equal to 0.1 mm, and more preferably between 0.01 mm and 0.05 mm. When the radius of curvature of the rounded portion 63c satisfies the above numerical range, it is possible to prevent cracks from forming at the bottom of the cutting groove 63 while the electrode 60 is running during the winding process or the like.

[0173] Multiple subsections 61 may have an increasing lower interior angle θ from the core side to the outer periphery. For example, the lower interior angle θ of multiple subsections 61 may increase gradually or in steps from the core side to the outer periphery. The lower interior angle θ is the angle between a straight line extending from the bottom 63a of the cutting groove 63 and a straight line extending from the side 53b of the subsection 61. When the subsection 61 is symmetrical, the lower interior angles θ on the left and right sides are approximately the same.

[0174] As the radius of the electrode assembly increases, the radius of curvature increases. If the lower inner angle θ of the segment 61 increases with the increase in the radius of the electrode assembly, when the segment 61 is bent, the stress generated in the radial and circumferential directions can be relaxed. Also, if the lower inner angle θ increases, when the segment 61 is bent, both the area overlapping with the inner segment 61 and the number of overlapping layers increase, so that the welding strength can be ensured uniformly in the radial and circumferential directions, and the bent surface region can be formed flat.

[0175] Preferably, the lower inner angle θ can be determined by the radius of the winding turn where the segment 61 is located and the width D of the segment 61.

[0176] FIG. 6d is a schematic diagram for explaining the mathematical formula for determining the lower inner angle θ of the segment 61.

[0177] Referring to FIG. 6d, it is ideal that the sides of the segment 61 coincide with the line segments AE and DE that connect the center E of the core with A and D which are the two ends of the line segment AD corresponding to the width D of the segment 61.

[0178] When the sides of the segment 61 extend in the most ideal direction, the lower inner angle θ of the segment 61 refer can be approximately determined from the width D of the segment 61 and the radius r of the winding turn where the segment 61 is located using the following mathematical formula 4 when assuming that the line segment EF is approximately equal to the line segments AE and DE.

[0179] [Mathematical formula 4] [Number] The angle of the mathematical formula 4 is the lower inner angle θ of the segment 61 referThis is the ideal reference angle. On the other hand, a separation pitch P exists between adjacent segment sections 61 located in the same turn. The length of the separation pitch P is denoted by p. Because the separation pitch P exists between adjacent segment sections 61, a tolerance of 50% of the separation pitch P can be given to the lower interior angle θ. That is, the width of the upper edge BC of the segment section 61 can increase by a maximum of p / 2 up to the upper edge B'C'. The lower interior angle θ', with the tolerance reflected, can be expressed by the following equation 5. Lower interior angle θ refer ∠BAG is the ideal reference angle, and the lower interior angle θ' is the angle ∠B'AG' which reflects the tolerance due to the separation pitch P. In equation 5, H is the height of the segment 61, and p corresponds to the separation pitch.

[0180] [Formula 5]

number

[0181] [Formula 6]

number

[0182] As another example, multiple subsections 61 may have a lower interior angle θ that gradually or stepwise increases from the core side to the outer periphery side in groups of one or more.

[0183] On the other hand, the lower interior angle on the left side of the segment 61 does not have to be equal to the lower interior angle on the right side. Nevertheless, it is still possible to design it so that at least one of the lower interior angles θ satisfies the above equation 6.

[0184] Referring further to Figure 4, the width d of the first part B1 is B1 The design is such that when the segment 61 of the third part B2 is bent toward the core, the core of the electrode assembly is exposed outward by more than 90% relative to its diameter. B1 The width d of the first portion B1 may increase in proportion to the bend length of the segment 61 of group 1. The bend length corresponds to the length from the bend point to the upper edge of the segment 61. Preferably, when the electrode 60 is used to manufacture an electrode assembly of a cylindrical battery of form factor 4680, the width d of the first portion B1 B1 This can be set to 180 mm to 350 mm depending on the diameter of the electrode assembly core and the height of the segment 61 included in group 1.

[0185] The bending point of the segment 61 can be set on a line passing through the bottom of the cutting groove 63 or at a point a predetermined distance above that line. If the segment 61 is bent toward the core at a point a predetermined distance from the bottom of the cutting groove 63, the radial superposition of the segment segments becomes easier. When the segment 61 is bent, the outer segment segments press against the inner segment segments with respect to the center of the core. At this time, if the bending point is a predetermined distance from the bottom of the cutting groove 63, the superposition of the segment segments becomes easier as the inner segment segments are pressed in the winding axis direction by the outer segment segments. The separation distance of the bending point is preferably 1 mm or less. Since the minimum height of the segment segment is 2 mm, the ratio of the separation distance of the bending point to the minimum height may be 50% or less.

[0186] In one example, the width of each segment group may be designed to constitute the same winding turn of the electrode assembly. Here, the winding turns can be counted relative to the end of the first portion B1 in the wound state of the electrode 60.

[0187] In other modifications, the width of each segment group may be designed to constitute at least one winding turn of the electrode assembly.

[0188] In further variations, the width and / or height and / or spacing of the sections 61 belonging to the same section group may increase or decrease gradually and / or stepwise and / or irregularly within the group or between adjacent groups.

[0189] Groups 1 to 8 are merely examples of segment groups included in the third section B2. The number of groups, the number of segment segments 61 included in each group, and the width of the groups can preferably be adjusted so that the segment segments 61 overlap in multiple layers, thereby maximally distributing stress during the bending process of the plain section 43 and ensuring sufficient welding strength with the current collector.

[0190] When there is only one subsection group, the height of the subsection 61 in the third part B2 may be uniform.

[0191] The segmentation structure of the third section B2 can be extended to the second section B3 (see dotted line). In this case, the second section B3, like the third section B2, may also contain multiple segments. Preferably, the segmentation structure of the second section B3 may be substantially identical to the outermost group of segments in the third section B2. In this case, the segments contained in the second section B3 and the third section B2 may have substantially the same width, height, and spacing pitch. As a variation, the segments of the second section B3 may have a larger width and / or height and / or spacing pitch than those of the third section B2.

[0192] In the third part B2, the sections in which the height of the segment 61 increases in stages (groups 1 to 7) with respect to the winding direction of the electrode 60 are defined as variable segment height sections, and the last group of segment 61 (group 8) can be defined as a uniform height section in which the height of the segment 61 is maintained uniformly.

[0193] In other words, in the third part B2, the height of the segment 61 is from h1 to h N When it increases gradually up to h1~h N-1 An interval in which a segment 61 with a height of (where N is a high index and is a natural number greater than or equal to 2) is placed corresponds to a height-variable interval, h NThe section in which the segment 61 having a certain height is arranged corresponds to the uniform height section. The ratio of the variable height section to the uniform height section with respect to the length of the electrode 60 in the winding direction will be described later with reference to a specific embodiment.

[0194] When electrode 60 is used to manufacture an electrode assembly for a cylindrical battery of form factor 4680, the width d of the first part B1 is B1 The width can be 180-350mm. The width of Group 1 can be 35-40% of the width of Part 1 B1. The width of Group 2 can be 130-150% of the width of Group 1. The width of Group 3 can be 120-135% of the width of Group 2. The width of Group 4 can be 85-90% of the width of Group 3. The width of Group 5 can be 120-130% of the width of Group 4. The width of Group 6 can be 100-120% of the width of Group 5. The width of Group 7 can be 90-120% of the width of Group 6. The width of Group 8 can be 115-130% of the width of Group 7. The width of Part 2 B3 d B3 This can be 180-350 mm, similar to the width of the first section B1.

[0195] The widths of groups 1 through 8 do not show a constant increasing or decreasing pattern. This is because, although the width of the segmental sections gradually increases from group 1 to group 8, the number of segmental sections within a group is limited to an integer, and the electrode thickness has a slight deviation in the winding direction. Therefore, the number of segmental sections may decrease in a particular segmental section group. Consequently, the width of the groups may show an irregular pattern of change from the core side to the outer circumference, as illustrated above.

[0196] In other words, when the winding widths for three consecutively adjacent segment groups in the circumferential direction of the electrode assembly are W1, W2, and W3, respectively, the combination of segment groups may include one in which W3 / W2 is smaller than W2 / W1.

[0197] In the above specific examples, Groups 4 to 6 correspond to the above cases. The width ratio of Group 5 to Group 4 is 120 to 130%, and the width ratio of Group 6 to Group 5 is 100 to 120%, and its value is smaller than 120 to 130%.

[0198] When the plain portion 43 of the electrode 60 has a slit structure, the third portion B2 corresponding to the slit section includes a plurality of slit groups 61g arranged via the inter-group separation interval P along the winding direction (X-axis) as shown in Fig. 7a g and can include. The number of slits 61 included in the slit group 61g can be at least one or more. The section corresponding to the inter-group separation interval P g corresponds to a slit omission section 64 without slits.

[0199] The inter-group separation interval P g can gradually or stepwise increase from the core side toward the outer peripheral side. The height of the plain portion existing in the slit omission section 64 can correspond to the height of the first portion B1 and / or the second portion B3.

[0200] Referring to Fig. 7b, the inter-group separation interval P of the slit groups 61g arranged in the same winding turn (k turn or k + 1 turn) of the electrode assembly JR g is substantially the same, and the inter-group separation interval P g can also gradually increase as the winding turn increases from the k turn to the k + 1 turn.

[0201] The inter-group separation interval P g can be set to form at least one slit alignment portion 66 along the circumferential direction with respect to the center of the core C of the electrode assembly JR when the electrode 60 is wound as shown in Fig.  7c. In the drawing, the dotted line schematically shows the winding turn, and the thick solid line schematically shows the slit group 61g arranged in the winding turn. The slit group 61g can be divided into one or more slits 61. The structure shown in Fig. 7c is the positive electrode side structure of the electrode assembly JR. However, the same structure can also be applied to the negative electrode side of the electrode assembly JR.

[0202] The segment alignment section 66 is a section in which the segment group 61g is arranged radially when the electrode 60 is wound up. The segment alignment section 66 is formed on one end face and / or the other end face of the electrode assembly JR perpendicular to the winding axis (Y axis) direction.

[0203] There may be n segment alignment sections 66, where n is 2, 3, 4, 5, 6, 7, 8, or 9. A configuration with only one segment alignment section 66 is also not excluded.

[0204] When there are n segment alignment sections 66, n segment groups 61g can be arranged in the same winding turn. The n segment groups 61g can be arranged at substantially equal intervals along the winding direction (X-axis).

[0205] The n segment alignment sections 66 can be arranged rotationally symmetrically with respect to the center of the core C. The angles of rotational symmetry can be 40°, 45°, 60°, 72°, 90°, 120°, or 180°. Alternatively, the n segment alignment sections 66 can be arranged point-symmetrically with respect to the center of the core C.

[0206] The n segment alignment sections 66 may have a structure that extends radially from the center of the core of the electrode assembly JR. A radial extension structure means a structure in which the circumferential width of a certain region gradually or in steps as it moves from the core side to the outer circumference side.

[0207] The segment alignment section 66, when viewed from the winding axis direction, may have a geometric shape consisting of an inner arc Arc1 adjacent to the core side of the electrode assembly JR, an outer arc Arc2 adjacent to the outer circumference of the electrode assembly JR, and two lines L1 and L2 connecting the ends of the arcs of the winding turns in which each segment group 61g is located, from the core side to the outer circumference. The two lines L1 and L2 may be straight lines, curves, or a combination thereof. As will be described later, the two lines L1 and L2 may have a nonlinear and irregular change pattern along the radial direction.

[0208] Preferably, the segment alignment section 66 may be a sector shape with the central portion removed. In addition to a sector shape, the segment alignment section 66 may have the form of a geometric figure such as a square, rectangle, parallelogram, or trapezoid.

[0209] The segment alignment section 66 may contain p segment groups 61g (where p is a natural number greater than 2) arranged radially. The number of segment groups 61g contained in each segment alignment section 66 may be the same or different. The difference in the number of segment groups 61g may be 1 to 3.

[0210] The height of the segment 61 contained in p segment groups 61g may increase in stages from the core side to the outer circumference side. Alternatively, the height of the segment 61 contained in p segment groups 61g may be substantially the same along the radial direction. Furthermore, the above-described configuration regarding the width, height, and spacing pitch of the segment 61 can be applied substantially the same in this embodiment as well. That is, the other configurations may be the same as in the above-described embodiment, except that the electrode 60 further includes a plurality of segment omission sections 64.

[0211] Electrolyte-impregnated portions 55 can be formed between adjacent segment alignment portions 66 in the circumferential direction. The electrolyte-impregnated portions 55 may extend radially from the center of the core C.

[0212] The electrolyte-impregnated portion 55 corresponds to the winding turn portion formed as the plain portion 43 region, which is provided between adjacent segment groups 61g in the winding direction (X-axis), is wound. The electrolyte-impregnated portion 55 is the section in which the electrolyte EL is mainly impregnated, and is lower than the height of the segment alignment portion 66 in the winding axis direction (Y-axis).

[0213] As shown in Figure 7c, the electrolyte-impregnated portion 55 does not have any segmental segments 61 protruding to the outside of the separation membrane Se. Furthermore, in the electrolyte-impregnated portion 55, the ends of the active material layer a1 of the positive electrode E1 and the ends of the active material layer a2 of the negative electrode E2 are recessed downward by a predetermined distance from the ends of the separation membrane Se between adjacent separation membrane Ses in the radial direction of the electrode assembly JR. Therefore, insulation between the positive electrode E1 and the negative electrode E2 can be maintained. In the embodiment, the separation distance may be 0.6 mm to 1 mm. An insulating coating layer 44 may be formed on at least one of the ends of the positive electrode E1 and 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 separation membrane arrangement structure shown in Figure 7c can be applied to the other end of the electrode assembly JR. Preferably, at the other end of the electrode assembly JR, the insulating coating layer 44 and the sliding portion may be formed at the end of the negative electrode E2.

[0214] The electrolyte EL can be impregnated into the electrode assembly JR while directly contacting the positive electrode E1 and negative electrode E2 through a gap provided between the ends of the separation membrane Se. Specifically, the electrolyte EL dropped onto the top of the electrode assembly JR quickly permeates into the electrode assembly JR while simultaneously contacting the ends of the positive electrode E1 and negative electrode E2 and the ends of the separation membrane Se. This significantly improves the electrolyte impregnation properties (speed and uniformity).

[0215] In this embodiment, the central points of the arc of the winding turn where the p segment groups 61g are located are C1 to C1, respectively, from the core side to the outer circumference. p It can be defined as follows.

[0216] If the thickness of the electrodes included in the electrode assembly JR perfectly matches the design thickness, then, as shown in Figure 7c, the midpoint C1~C of the winding turn arc p This is a predetermined alignment line L extending radially from the center of the core C. align It is located above. Therefore, the segment alignment section 66 has a symmetrical geometric shape.

[0217] However, the positive and negative electrodes used in the manufacture of the electrode assembly JR have tolerances from the designed thickness. The tolerance can be a positive number or a negative number. When the tolerance is a positive number, the electrode is thicker than the designed thickness. Conversely, when the tolerance is a negative number, the electrode is thinner than the designed thickness. The positive electrode may have a positive tolerance and the negative electrode may have a negative tolerance, and vice versa. Also, both the positive and negative electrodes may have a positive tolerance or a negative tolerance.

[0218] The tolerances of the positive and negative electrodes can be added together as the electrode tolerance. As an example, if the positive electrode has a positive tolerance of 2 μm and the negative electrode has a positive tolerance of 1 μm, the electrode tolerance can be 3 μm. As another example, if the positive electrode has a negative tolerance of 1 μm and the negative electrode has a positive tolerance of 2 μm, the electrode tolerance can be 1 μm.

[0219] As shown in FIGS. 7d and 7e, if the thicknesses of the positive and negative electrodes are different from the designed thickness, the central points C1 to C of the arcs of the winding turns p are displaced from the alignment line L align by.

[0220] As an example, if the tolerance of the electrode is positive, the radius at which each winding turn is located increases from the designed radius. Therefore, the segmented slice group 61g rotates in the opposite direction to the winding direction of the electrode assembly JR with reference to the designed position on the alignment line L align as shown in FIG. 7d. θ + represents the clockwise rotation angle.

[0221] As another example, if the tolerance of the electrode is negative, the radius at which each winding turn is located decreases from the designed radius. Therefore, the segmented slice group 61g rotates in the same direction as the winding direction of the electrode assembly JR with reference to the designed position on the alignment line L align as shown in FIG. 7e. θ - represents the counterclockwise rotation angle.

[0222] Therefore, when the tolerance of the electrode is not 0 based on the designed thickness of the electrode, the central points C1 to C of the arcs of the winding turns where each segmented slice group 61g is located pAt least a portion of these is an alignment line L extending radially from the center of the core. align It may disappear from the top.

[0223] If the electrodes have a thickness tolerance, the center point C1~C of the winding turn p Alignment line L align The distance separating from the core in the circumferential direction may increase from the core side towards the outer circumference. This is because the increase in the radius of the winding turn due to the electrode thickness tolerance accumulates proportionally from the core side towards the outer circumference.

[0224] On the other hand, the electrode tolerance is a numerical value based on an average concept. Therefore, depending on the position in the winding direction (X-axis), the electrode thickness may differ from the thickness corresponding to "design thickness + tolerance". Consequently, in the segment alignment section 66, the amount of rotation of the segment group 61g located in each winding turn portion may differ, as shown in Figure 7f. If the amount of rotation of each segment group 61g differs, the lines L1 and L2 connecting both ends of the winding turn portions included in the segment alignment section 66 may be deformed from straight lines to irregular lines. However, the rotational symmetry, point symmetry, or radial extension structure of the segment alignment section 66 can be maintained.

[0225] Figure 7f shows the case where the electrode tolerance is positive. It is obvious that when the electrode tolerance is negative, the segment group 61g can rotate counterclockwise.

[0226] In the embodiment, when the electrode tolerance is positive, C1~C p 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more are aligned line L align It can rotate in the opposite direction to the winding direction of the electrode assembly JR, using as a reference. Also, when the tolerance of the electrodes is negative, C1~C p 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more are aligned line L align It can rotate in the winding direction of the electrode assembly JR with respect to this reference point.

[0227] When the electrodes have a positive or negative tolerance, the more uniform the thickness of the positive and negative electrodes in the winding direction of the electrodes, the more aligned the alignment line L is.align C1~C that deviates from p The ratio can converge to 100%.

[0228] Referring to Figure 7g, the segment group 61g included in the segment alignment section 66 can be bent toward the core C of the electrode assembly JR to form a bent surface region F.

[0229] The electrode assembly JR may include a current collector (not shown) welded to the bent surface region F. Reference numeral W. L The arrow indicates the weld line of the current collector. Weld line W L These can be formed on the bent surface region F of each segment alignment portion 66.

[0230] Weld line W L This could be a laser welding line. Welding line W L When forming by laser welding, the weld line W L The minimum width can be 1 mm. Welding line W L The circular pattern schematically represents the laser beam irradiation points. The minimum width is obtained when the welding points are formed radially in a two-row structure by the laser beam.

[0231] Preferably, the arc of the winding turn in which the p segment groups 61g included in the segment alignment section 66 are located is the welding line W of the current collector. L , and optionally, weld line W L A virtual line W extending from it with the same width * L It can intersect with this.

[0232] The arc of the winding turn and the weld line W as described above L , and optionally a virtual line W * L If the intersection condition is met, then the weld line W L The entire region can be superimposed on the bent surface region F, allowing for stable welding.

[0233] The tolerance conditions are preferably met by designing the size of the inscribed angle of the segment alignment section 66 in advance. That is, the thickness tolerance of the electrodes used in the actual manufacture of the electrode assembly JR is predicted in advance, relative to the design conditions for the electrode thickness. The electrode thickness tolerance can be 1 μm to 5 μm. It is preferable for the electrode thickness tolerance to converge to 0, but a thickness tolerance of about 1 μm is unavoidable. However, a thickness tolerance greater than 5 μm will significantly change the diameter of the electrode assembly JR and have a negative impact on the battery quality. Therefore, it is preferable that the electrode thickness tolerance be controlled to about 1 μm to 5 μm. Once the electrode thickness tolerance is predicted, assuming that there is no deviation in the electrode thickness along the winding direction of the electrode, the maximum rotation angle clockwise or counterclockwise of the segment group 61g can be determined based on the predicted tolerance.

[0234] Figures 7h and 7i show the maximum clockwise rotation angle (θ) for segment group 61g, respectively, as a parameter calculated based on the predicted thickness tolerance of the electrode. +,max ) and the maximum angle of rotation counterclockwise (θ -,max The maximum rotation angle (θ) is shown. Here, counterclockwise is the same direction as the winding direction, and clockwise is the opposite direction of the winding direction. +,max ) is obtained when the electrode thickness tolerance is positive, and the maximum rotation angle (θ -,max This is obtained when the electrode thickness tolerance is negative.

[0235] Table 4 below shows the θ calculated for the electrode thickness tolerance. +,max and θ -,max The calculated values ​​are shown. Positive electrode tolerance, negative electrode tolerance, and electrode tolerance may have values ​​other than those shown in the table. Also, under conditions where the electrode tolerance is the same, various combinations of positive electrode tolerance and negative electrode tolerance are possible. For example, even if the positive electrode tolerance is 1.3 μm and the negative electrode tolerance is 1.7 μm, it still falls under tolerance condition 5, where the electrode tolerance is 3 μm.

[0236] [Table 4]

[0237] Referring to Table 4, the minimum inscribed angle of the segment alignment section 66 is θ -,max and θ +,max It can be designed so that it corresponds to the sum of the following values. Designing the segment alignment section 66 to have the minimum inscribed angle means the width of the segment group 61g and the spacing P between groups. g By adjusting this, it means that when the electrodes are wound up, the segment group 61g is arranged in a sector-shaped region having an inscribed angle greater than the minimum inscribed angle.

[0238] The actual shape of the segment alignment section 66 is deformed as shown in Figure 7f by the rotation of the segment group 61g when viewed from the winding axis direction (Y axis). However, the arc of the winding turn in which the segment group 61g is located and the weld line W L Because they intersect, there are no problems with the progress of the welding process.

[0239] Referring to Table 4, if the electrode tolerance is expected to be controllable to ±1 μm or less, the segment group 61g included in the segment alignment section 66 can be rotated up to 19° clockwise and up to 19° counterclockwise. Therefore, excluding the electrode thickness tolerance, from a purely design standpoint, the width of the segment group 61g and the inter-group spacing P should be such that the inscribed angle of the segment alignment section 66 exceeds 38°. g If designed this way, the electrode assembly JR that is actually manufactured will have a weld line W L , and optionally, weld line W L A virtual line W extending from * L The condition is met that the current collector can be stably welded onto the bent surface region F when it intersects with the arc of the winding turn corresponding to segment group 61g.

[0240] As another example, if the electrode tolerance is expected to be controllable to ±2 μm or less, the segment groups 61g included in the segment alignment section 66 can be rotated up to 34° clockwise and up to 34° counterclockwise. Therefore, excluding the electrode thickness tolerance, from a purely design standpoint, the width of the segment groups 61g and the inter-group spacing P should be such that the inscribed angle of the segment alignment section 66 exceeds 68°. gIf designed this way, the electrode assembly JR that is actually manufactured will have a weld line W L , and optionally, weld line W L A virtual line W extending from * L The condition is met that the current collector can be stably welded onto the bent surface region F when it intersects with the arc of the winding turn corresponding to segment group 61g.

[0241] As another example, if the electrode tolerance is expected to be controllable to ±3 μm or less, the segment groups 61g included in the segment alignment section 66 can be rotated up to 50° clockwise and up to 50° counterclockwise. Therefore, excluding the electrode thickness tolerance, from a purely design standpoint, the width of the segment groups 61g and the inter-group spacing P can be adjusted so that the inscribed angle of the segment alignment section 66 exceeds 100°. g If designed this way, the electrode assembly JR that is actually manufactured will have a weld line W L , and optionally, weld line W L A virtual line W extending from * L The condition is met that the current collector can be stably welded onto the bent surface region F when it intersects with the arc of the winding turn corresponding to segment group 61g.

[0242] As another example, if the electrode tolerance is expected to be controllable to ±4 μm or less, the segment groups 61g included in the segment alignment section 66 can be rotated up to 66° clockwise and up to 66° counterclockwise. Therefore, excluding the electrode thickness tolerance, from a purely design standpoint, the width of the segment groups 61g and the inter-group spacing P should be such that the inscribed angle of the segment alignment section 66 exceeds 132°. g If designed this way, the electrode assembly JR that is actually manufactured will have a weld line W L , and optionally, weld line W L A virtual line W extending from * L The condition is met that the current collector can be stably welded onto the bent surface region F when it intersects with the arc of the winding turn corresponding to segment group 61g.

[0243] As another example, if the electrode tolerance is expected to be controllable to ±5 μm or less, the segment groups 61g included in the segment alignment section 66 can be rotated up to 88° clockwise and up to 88° counterclockwise. Therefore, excluding the electrode thickness tolerance, from a purely design standpoint, the width of the segment groups 61g and the inter-group spacing P should be such that the inscribed angle of the segment alignment section 66 exceeds 176°. g If designed this way, the electrode assembly JR that is actually manufactured will have a weld line W L , and optionally, weld line W L A virtual line W extending from * L The condition is met that the current collector can be stably welded onto the bent surface region F when it intersects with the arc of the winding turn corresponding to segment group 61g.

[0244] The number of segment alignment sections 66 can be determined by considering the design condition for the minimum inscribed angle of the segment alignment section 66, which is determined by the thickness tolerance of the electrode.

[0245] For example, if the electrode thickness tolerance is expected to be controllable to ±1 μm or less, the minimum inscribed angle of the segment alignment section 66 is greater than 38°, so the number of segment alignment sections 66 can be determined to be in the range of 1 to 9.

[0246] As another example, if the electrode thickness tolerance is expected to be controllable to ±2 μm or less, the number of segment alignment sections 66 can be determined to be in the range of 1 to 5, since the minimum inscribed angle of the segment alignment section 66 is greater than 68°.

[0247] As another example, if the electrode thickness tolerance is expected to be controllable to ±3 μm or less, the minimum inscribed angle of the segment alignment section 66 is greater than 100°, so the number of segment alignment sections 66 can be determined to be in the range of 1 to 3.

[0248] As another example, if the electrode thickness tolerance is expected to be controllable to ±4 μm or less, the number of segment alignment sections 66 can be determined to be in the range of 1 to 2, since the minimum inscribed angle of the segment alignment section 66 is greater than 132°.

[0249] As another example, if the electrode thickness tolerance is expected to be controllable to ±5 μm or less, the number of segment alignment sections 66 can be determined to be in the range of 1 to 2, since the minimum inscribed angle of the segment alignment section 66 is greater than 176°.

[0250] In the present invention, the electrode tolerance is not limited to those described above. Therefore, those skilled in the art will be able to determine θ for other values ​​outside of the electrode tolerances shown in the table. -,max and θ +,max By determining this, the design conditions for the minimum inscribed angle of the segment alignment section 66 can be easily calculated.

[0251] On the other hand, when calculating the minimum inscribed angle condition of the segment alignment section 66, the weld line W L It is preferable to further consider the range.

[0252] Referring to Figure 7j, weld line W L In order to stably form the weld line W L The maximum value (θ) of the inscribed angle subtended by half of the arc of the intersecting winding turn, calculated by the following equation 7. weld,max It is preferable to add this value to the minimum inscribed angle of the segment alignment section 66.

[0253] [Equation 7] θ weld,max =(360° × 0.5 × d arc ) / (2πr) Here, d arc The weld line W L This is the length of the arc of the winding turn that intersects with the curve and has the largest inscribed angle, where r is the radius of the arc of that winding turn relative to the center of the core.

[0254] Weld line W L If it extends radially from the center of the core C of the electrode assembly JR with the same width, d arc The weld line W L This corresponds to the length of the arc of the winding turn that is closest to core C among the arcs of the winding turns that intersect with it.

[0255] Table 5 below shows d arc When is 1 mm, θ corresponds to the change in r. weld,max The calculation results are shown.

[0256] [Table 5]

[0257] θ calculated by equation 7 weld,max If this is added to the minimum inscribed angle of the segment alignment section 66, then even if the segment group 61g included in the segment alignment section 66 rotates clockwise or counterclockwise at the maximum angle, θ weld,max Because the segment alignment section 66 is expanded by the inscribed angle, the weld line W L It is possible to form this. On the other hand, the electrode assembly JR manufactured according to the embodiment of the present invention may further satisfy the following relational equation 8.

[0258] [Formula 8] θ design >θ max +θ weld,max Referring to Figure 8(a), the electrode assembly JR manufactured according to an embodiment of the present invention includes a segment alignment section 66 and an electrolyte impregnation section 55. The segment group 61g contained in the segment alignment section 66 is rotated in a predetermined direction rather than in the design position due to the electrode thickness tolerance. The rotation angle of the segment group 61g is less than or equal to the maximum rotation angle due to the electrode thickness tolerance.

[0259] Referring to Figure 8(b), θ design C1~C corresponds to the center point of the arc of the winding turn included in the segment alignment section 66 of the electrode assembly JR. p is the weld line W L Alignment line L overlaps with this. align When the arc of the winding turn is virtually rotated so that it is positioned above, it corresponds to the inscribed angle of the sector shape formed by the arc of the winding turn.

[0260] θ designAs explained with reference to Table 4, this has an angle value larger than the minimum inscribed angle of the segment alignment section 66, which was determined purely from a design perspective, taking into account the thickness tolerance of the electrodes.

[0261] θ max This is the alignment line L align This is the maximum rotation angle of the end of the segment group included in the segment alignment section 66, relative to θ. max This corresponds to the rotation angle of the end of the segment group located on the outermost periphery.

[0262] θ weld,max This rotates each segment group 61g contained in the segment alignment section 66 to its maximum extent so that the ends of the segment groups 61g are aligned along the alignment line L. align This is the angle value calculated using formula 7, with the position at the top as the reference point.

[0263] Preferably, the segments 61 contained in segment group 61g can be deformed into various forms while satisfying at least one of the following conditions.

[0264] Condition 1: The width of the bottom is wider than the width of the top.

[0265] Condition 2: The width of the bottom and the width of the top are equal.

[0266] Condition 3: The width is maintained at a constant level from bottom to top.

[0267] Condition 4: The width decreases from the bottom to the top.

[0268] Condition 5: The width decreases from the bottom to the top, then increases.

[0269] Condition 6: The width increases from the bottom to the top, then decreases.

[0270] Condition 7: The width increases from the bottom to the top and then remains constant.

[0271] Condition 8: The width decreases from the bottom to the top and then remains constant.

[0272] Condition 9: The interior angle on one side of the lower section is the same as the interior angle on the other side.

[0273] Here, the interior angle can 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 a curve, the interior angle is defined as the angle between the tangent line drawn at the lowest point of the curve and the width direction of the lower part of the segment.

[0274] Condition 10: The interior angle on one side of the lower section is different from the interior angle on the other side.

[0275] Condition 11: The interior angle on one side of the lower section and the interior angle on the other side of the lower section are acute, right, or obtuse, respectively.

[0276] Condition 12: It is symmetrical with respect to the winding axis direction.

[0277] Condition 13: It is asymmetrical with respect to the winding axis direction.

[0278] Condition 14: The sides are straight.

[0279] Condition 15: The sides are curved.

[0280] Condition 16: The sides are convex outwards.

[0281] Condition 17: The sides are convex inward.

[0282] Condition 18: The upper and / or lower corners are structured such that two straight lines intersect.

[0283] Condition 19: The upper and / or lower corners are structured in which a straight line and a curve intersect.

[0284] Condition 20: The upper and / or lower corners are structured in a way that curves intersect.

[0285] Condition 21: The top and / or bottom corners are rounded.

[0286] Figure 9 is an illustrative diagram showing the shape of a section according to a modified form of the present invention.

[0287] As illustrated, the section can have a variety of geometric shapes with a dotted line connecting the bottoms of the cutting grooves on both sides as its base. The geometric shape has a structure in which at least one straight line, at least one curve, or a combination thereof is connected. For example, the section can have a variety of shapes such as polygons, rounded patterns, or combinations thereof.

[0288] Specifically, the segment can be a symmetrical trapezoid (circle a); an asymmetrical trapezoid (circle b); a parallelogram (circle c); a triangular shape (circle l); a pentagon (circle k); an arc shape (circle e); or an ellipse (circle f).

[0289] The shape of the section is not limited to that shown in Figure 9, and can be modified to other polygonal shapes, other round shapes, or combinations thereof, so as to satisfy at least one of the conditions 1 to 21 described above.

[0290] In the polygonal shapes of the segmental sections, circles a, b, c, k, and l, the upper corners and / or lower corners may be the shape of two intersecting straight lines or rounded (see the enlarged view of the upper and lower corners of circle a).

[0291] In the polygonal shapes of the segmental sections, circles a, b, c, k, and l, and the round shapes of the segmental sections, circles e and f, the interior angles θ1 and θ2 on one side of the lower section may be the same or different, and these interior angles θ1 and θ2 on the other side may be acute, right, or obtuse, respectively. An interior angle is the angle between the base and the sides of a geometric figure. When the sides are curves, straight lines may be replaced by tangents extending from the intersection of the base and the sides.

[0292] The shape of the sides of polygonal segments can be varied in many ways.

[0293] For example, the side of morphological circle a of the segmental section can be transformed into a curve that bulges outward, like morphological circle d, or into a curve that is concave inward, like morphological circle g or circle j.

[0294] As another example, the side of morphological circle a of the segmental section can be deformed into a rib line that is concave inward, like morphological circle h or circle i. Although not shown, the side of morphological circle a of the segmental section can also be deformed into a rib line that bulges outward.

[0295] In the morphological forms of the segment sections, round d, round g, round j, round h, and round i, in which the sides are deformed in various ways, the interior angle θ1 on one side and the interior angle θ2 on the other side of the lower section are either the same or different, and the interior angles θ1 and θ2 on the other side of the lower section can be acute, right, or obtuse, respectively.

[0296] The width of the segment can exhibit diverse patterns of change from the bottom to the top.

[0297] As one example, the width of the segment may be kept constant from bottom to top (morphology circle c). As another example, the width of the segment may gradually decrease from bottom to top (morphology circles a, b, d, e, f, and g). As yet another example, the width of segment 61 may gradually decrease from bottom to top and then increase (morphology circles i and j). As yet another example, the width of the segment may gradually increase from bottom to top and then decrease (morphology circle k). As yet another example, the width of the segment may gradually decrease from bottom to top and then be kept constant (morphology circle h). Although not shown, the width of the segment may gradually increase from bottom to top and then be kept constant.

[0298] On the other hand, among the segmental section shapes illustrated in Figure 9, the polygonal shape with a flattened top can be rotated by 180°. For example, when segmental section shapes a, b, d, or g are rotated by 180°, the width of the segmental section may gradually increase from the bottom to the top. As another example, when segmental section shape h is rotated by 180°, the width of the segmental section may be kept constant from the bottom to the top and then gradually increase.

[0299] In the above-described embodiment (modified form), according to another embodiment of the present invention, it is also possible to change the shape of the segment 61 along the region of the third part B2. For example, a round shape (e.g., semicircular, elliptical, etc.) that is advantageous for stress distribution can be applied to sections where stress is concentrated, and a polygonal shape (e.g., quadrilateral, trapezoid, parallelogram, etc.) that maximizes the area can be applied to sections where stress is relatively low.

[0300] In other embodiments, the multiple sections may have different shapes individually, in groups, or in groups of two or more, along one direction parallel to the winding direction of the electrode assembly.

[0301] In the above-described embodiment (modified form), the segmentation structure of the third part B2 can also be applied to the first part B1. However, if the segmentation structure is applied to the first part B1, when the segmentation piece 61 of the third part B2 is bent due to the radius of curvature of the core, there is a risk of reverse forming occurring, where the end of the first part B1 bends outward. Therefore, it is preferable not to apply the segmentation structure to the first part B1, or, if the segmentation structure is applied, to adjust the width and / or height and / or spacing pitch of the segmentation pieces 61, 61' to a level that does not cause reverse forming, taking into account the radius of curvature of the core.

[0302] According to yet another embodiment of the present invention, after the electrode 60 is wound up as an electrode assembly JR, the segmented segments 61 that are exposed on the upper and lower sides of the electrode assembly JR and constitute the segmented segment alignment section 66 can overlap in multiple layers along the radial direction of the electrode assembly JR to form a bent surface region F.

[0303] Figure 10 is a schematic diagram showing a cross-section of the bent surface region F formed when the segment 61 included in the segment alignment section 66 is bent toward the core C side of the electrode assembly JR. The cross-sectional structure of the bent surface region F shows the structure when the segment alignment section 66 is cut radially. The bent surface region F is formed when the segment 61, whose height changes in stages from the core side toward the outer circumference of the electrode assembly JR, is bent. In Figure 10, only the left side of the cross-section of the bent surface region F is shown with reference to the winding axis of the electrode assembly JR. The bent surface region F can be formed on both the upper and lower parts of the electrode assembly JR.

[0304] Referring to Figure 10, the bent surface region F has a structure in which subsections 61 are superimposed in multiple layers in the winding axis direction. The superposition direction is the winding axis direction (Y axis). Section circle 1 is a subsection-omitted section (first part) where there are no subsections, and sections circle 2 and circle 3 are sections where winding turns containing subsection groups 61g arranged in the winding direction with spacing between groups. Section circle 2 is a height-variable section in which the height of the subsections 61 changes, and section circle 3 is a height-uniform section in which the height of the subsections is maintained uniformly up to the outer circumference of the electrode assembly. As will be described later, the radial lengths of sections circle 2 and section circle 3 may change. On the other hand, a plain section (second part B3) included in at least one winding turn, including the outermost winding turn, does not have to contain a subsection structure. In this case, the second part can be excluded from section circle 3.

[0305] In section 2, the height of the segment 61 is equal to the radius r1~r of the electrode assembly JR. N Minimum height h1 (=h) in the interval min ) from maximum height h N (=h max ) can change in stages up to r. The height-variable interval in which the height of the segment 61 changes is r1 to r N Therefore, the radius r N From the radius R of the electrode assembly JR, the height of the segment 61 is h N It is maintained uniformly. Uniform height means that the height deviation is within 5%.

[0306] At any radial position in section circle 2 and section circle 3, the number of layers of subsection 61 varies depending on the radial position. Also, the number of layers of subsection 61 depends on the width of section circle 2 and the minimum height h1 and maximum height h of the subsection in the height-variable section of subsection 61. N Furthermore, this can vary depending on the height change Δh of the segment 61. The number of stacked segment 61 is the number of segment segments that intersect a virtual line drawn in the winding axis direction from an arbitrary radial position of the electrode assembly JR.

[0307] Preferably, the height, width (length in the winding direction), and spacing pitch of the segmentation segments 61 can be adjusted according to the radius of the winding turn containing the segmentation segments 61, thereby optimizing the number of layers of segmentation segments 61 at each position in the bent surface region F to match the required welding strength of the current collector.

[0308] First, when the minimum height h1 of the segment 61 is the same in the height-variable interval (circle 2), the maximum height h of the segment 61 N The following will explain, with specific examples, how the number of layers of the segment 61 changes along the radial direction of the folded surface region F due to the change in [the specified parameter].

[0309] Electrode assemblies for Examples 1-1 to 1-7 were prepared. The electrode assemblies in the examples have a radius of 22 mm and a core diameter of 4 mm. The positive and negative electrodes included in the electrode assemblies have the electrode structure shown in Figure 4a. The second portion B3 of the positive and negative electrodes does not include a segment. The length of the second portion B3 is 2% to 4% of the total length of the electrode. The positive electrode, negative electrode, and separator membrane were wound using the method described with reference to Figure 2. The number of winding turns is between 48 and 56 turns, but the number of winding turns in the examples is 51 turns. The thicknesses of the positive electrode, negative electrode, and separator membrane are 149 μm, 193 μm, and 13 μm, respectively. The thicknesses of the positive and negative electrodes include the thickness of the active material layer. The thicknesses of the positive electrode current collector and negative electrode current collector are 15 μm and 10 μm, respectively. The lengths of the positive and negative electrodes in the winding direction are 3948 mm and 4045 mm, respectively.

[0310] In each embodiment, the minimum height of the segment 61 was set to 3 mm, starting from a radius of 5 mm in the variable height section of the segment 61 (circle 2). In addition, in each embodiment, the height of the segment 61 was increased by 1 mm for every 1 mm increase in radius, and the maximum height of the segment 61 varied from 4 mm to 10 mm.

[0311] Specifically, in Example 1-1, the height variable section (circle 2) of the segment 61 is 5 mm to 6 mm, and the height of the segment 61 changes from a radius of 3 mm to 4 mm. In Example 1-2, the height variable section (circle 2) of the segment 61 is 5 mm to 7 mm, and the height of the segment 61 changes from 3 mm to 5 mm. In Example 1-3, the height variable section (circle 2) of the segment 61 is 5 mm to 8 mm, and the height of the segment 61 changes from 3 mm to 6 mm. In Example 1-4, the height variable section (circle 2) of the segment 61 is 5 mm to 9 mm, and the height of the segment 61 changes from 3 mm to 7 mm. In Example 1-5, the height variable section (circle 2) of the segment 61 is 5 mm to 10 mm, and the height of the segment 61 changes from 3 mm to 8 mm. In Examples 1-6, the height of the segment 61 is variable in the range of 5 mm to 11 mm (circle 2), and the height of the segment 61 varies from 3 mm to 9 mm. In Example 1-7, the height of the segment 61 is variable in the range of 5 mm to 12 mm (circle 2), and the height of the segment 61 varies from 3 mm to 10 mm. In Examples 1-1 to 1-7, the height of the segment 61 is uniform from the radius corresponding to the upper limit of the height variable range (circle 2) to the outer circumference. For example, in Example 1-7, the height of the segment 61 is uniformly 10 mm from a radius of 12 mm to 22 mm. On the other hand, in the comparative example electrode assembly, the height of the segment 61 was maintained at a single height of 3 mm from a radius of 5 mm to a radius of 22 mm.

[0312] Figure 11a 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 part of the electrode assemblies according to Examples 1-1 to 1-7 and the comparative example. The folded surface region F is formed when the segments 61 included in the segment alignment section 66 are folded toward the core side of the electrode assembly JR. The folded surface region of the negative electrode shows substantially the same results. The horizontal axis of the graph is the radius relative to the center of the core, and the vertical axis of the graph is the number of stacked segments counted at each radial point. The same applies to Figures 11b and 11c, which will be described later.

[0313] Referring to Figure 11a, the uniform number of layers of the segmental intercepts interval b1 appears in common in Examples 1-1 to 1-7 and Comparative Example 1. The uniform number of layers interval b1 is the radius interval of the flattened region in each graph. The length of the uniform number of layers interval b1 increases as the maximum height of the segmental intercept decreases, with the uniform number of layers interval b1' in the Comparative Example being the longest. On the other hand, the number of layers of the segmental intercepts is equal to the maximum height of the segmental intercept h N It increases as the value increases. That is, the maximum height of the segment h N As the radius increases and the width of the variable-height section of the segment (circle 2) increases, the number of stacked segment segments increases, while the width of the uniform-number-of-stacks section b1 decreases. Outside the uniform-number-of-stacks section b1, a decreasing-number-of-stacks section b2 appears where the number of stacked segment segments decreases as the radius increases. The decreasing-number-of-stacks section b2 is a radial section where the number of stacked segment segments decreases as the radius of the electrode assembly increases. The uniform-number-of-stacks section b1 and the decreasing-number-of-stacks section b2 are adjacent in the radial direction and are complementary to each other. That is, if the length of one section increases, the length of the other section decreases. Also, in the decreasing-number-of-stacks section b2, the amount of decrease in the number of stacks is proportional to the distance from the uniform-number-of-stacks section b1.

[0314] From the perspective of the number of layers of segmentation segments, Examples 1-1 to 1-7 have 10 or more layers of segmentation segments in the uniform segmentation segmentation segmentation segmentation segment b1. The region with 10 or more layers of segmentation segments can be set as a preferred welding target region. The welding target region is the section in which at least a portion of the current collector is welded.

[0315] In Examples 1-1 to 1-7, the uniform layering section b1 begins at the radius point where the variable-height section of the segment (circle 2) begins. That is, the variable-height section (circle 2) starts at a radius of 5 mm and extends outwards.

[0316] Table 6 below shows the results of calculations for Examples 1-1 to 1-7 and Comparative Example 1, including the ratio of the length of the segment omission section (c) to the radius (ba) of the electrode assembly excluding the core with respect to the positive electrode, the ratio (e / f) of the length of the uniform number of layers section b1 to the length (f) from the radius point where the uniform number of layers section begins (5 mm) to the outermost point of the electrode assembly (22 mm), the ratio (d / f) of the length of the segment omission section (d) to the length (f) from the radius point where the uniform number of layers section begins (5 mm) to the outermost point of the electrode assembly (22 mm), the ratio (h) of the electrode region corresponding to the segment omission section to the total length of the electrode, the ratio (i) of the electrode region corresponding to the height variable section to the total length of the electrode, and the ratio (i) of the electrode region corresponding to the uniform height section to the total length of the electrode.

[0317] The negative electrode is almost identical to the positive electrode in all other parameters, except that it shows a difference of 0.1 to 1.2% with respect to parameter h. The sum of ratios h, i, and j is slightly different from 100%. This is because there is a section without a segment in the second part B3, which corresponds to the plain outer part of the electrode. For example, in Example 1-1, there is no segment in the second part B3, which corresponds to approximately 3% of the total length of the electrode. In Table 6, a to f are parameters based on the radial length, and h, i, and j are parameters based on the length in the winding direction of the electrode. Also, the parameters corresponding to ratios (%) are values ​​rounded to the first decimal place. These are substantially the same in Tables 7 and 8 described later.

[0318] [Table 6]

[0319] Referring to Examples 1-1 to 1-7 in Table 6, the number of layers of segmentation segments ranges from 11 to 27, and the ratio of the height-variable section (d) to the radius section (f) containing segmentation segments (d / f) is 6% to 41%. The ratio of the uniform number of layers section (e) to the radius section (f) containing segmentation segments (e / f) is 47% to 82%. The ratio of the segmentation-omitted section (c) to the radius (ba) of the electrode assembly excluding the core (c / (ba)) is 15%. The ratio of the length of the electrode region corresponding to the segmentation-omitted section to the total length of the electrode is 6%, the ratio of the length of the electrode region corresponding to the height-variable section to the total length of the electrode is 3% to 32%, and the ratio of the length of the electrode region corresponding to the height-uniform section to the total length of the electrode is 59% to 87%. The number of layers (g) in the uniform number of layers section is 10 or more in all Examples 1-1 to 1-7. The uniform layer count section (e) decreases as the variable section height section (d) increases, but the number of layers of the section (g) increases in the uniform layer count section (e). Preferably, the uniform layer count section (e) where the number of layers of the section (g) is 10 or more can be set as a welding target area.

[0320] Cylindrical batteries with the 1865 or 2170 form factor have an electrode assembly radius of approximately 9mm to 10mm. Therefore, compared to conventional cylindrical batteries, it is not possible to secure a radial length of 17mm in the segment section (f) and to secure a uniform stacking section (e) with 10 or more stacking segments in the 8mm to 14mm section compared to conventional cylindrical batteries. This is because, in conventional cylindrical batteries, if the core radius is designed to be 2mm, the same as in Examples 1-1 to 1-7, the radial section in which segment sections can be placed is effectively only 7mm to 8mm. Furthermore, in conventional cylindrical batteries, the length of the electrodes in the winding direction is in the 600mm to 980mm range. Such short electrode lengths are only about 15% to 24% of the electrode lengths used in Examples 1-1 to 1-7 (positive electrode 3948mm, negative electrode 4045mm). Therefore, the numerical ranges for parameters h, i, and j cannot be easily derived from the design specifications of conventional cylindrical batteries.

[0321] Next, in the section with variable segment height (circle 2 in Figure 10), the maximum height of the segment h N When the minimum height h1 of the segment is the same, we will explain, with specific examples, how the number of stacked segments changes along the radial direction of the folded surface region F due to the change in the minimum height h1 of the segment.

[0322] The electrode assemblies of Examples 2-1 to 2-5 have a radius of 22 mm and a core C diameter of 4 mm. The minimum height h1 in the height-variable section of the segment 61 (circle 2 in Figure 10) is the same as 4 mm, and the maximum height h N The width 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 width of the variable section height section (circle 2 in Figure 10) is 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm, respectively, and the section omitted section (circle 1 in Figure 10) is a radius section from 2 mm to 6 mm.

[0323] The electrode assemblies of Examples 3-1 to 3-4 have a radius of 22 mm and a core C diameter of 4 mm. The minimum height h1 in the height-variable section of the segment 61 (circle 2 in Figure 10) is the same as 5 mm, and the maximum height h N The width was varied from 7 mm to 10 mm in 1 mm increments. Therefore, in the electrode assemblies of Examples 3-1 to 3-4, the width of the variable section height section (circle 2 in Figure 10) is 2 mm, 3 mm, 4 mm, and 5 mm, respectively, and the section omitted section (circle 1 in Figure 10) is a radius section from 2 mm to 7 mm.

[0324] The electrode assemblies of Examples 4-1 to 4-3 have a radius of 22 mm and a core C diameter of 4 mm. The minimum height h1 in the height-variable section of the segment 61 (circle 2 in Figure 10) is the same as 6 mm, and the maximum height h N The width was varied from 8 mm to 10 mm in 1 mm increments. Therefore, in the electrode assemblies of Examples 4-1 to 4-3, the width of the variable section height section (circle 2 in Figure 10) is 2 mm, 3 mm, and 4 mm, respectively, and the section omitted section (circle 1 in Figure 10) is a radius section from 2 mm to 8 mm.

[0325] The electrode assemblies of Examples 5-1 to 5-2 have a radius of 22 mm and a core diameter of 4 mm. The minimum height h1 in the height-variable section of the segment 61 (circle 2 in Figure 10) is the same as 7 mm, and the maximum height h N The width was varied from 9 mm to 10 mm in 1 mm increments. Therefore, in the electrode assemblies of Examples 5-1 to 5-2, the width of the variable section height section (circle 2 in Figure 10) is 2 mm and 3 mm, respectively, and the section omitted section (circle 1 in Figure 10) is a radius section from 2 mm to 9 mm.

[0326] Figure 11b is a graph showing the results of counting the number of stacked segments measured radially in the bent surface region F of the positive electrode formed on the upper part of the electrode assemblies 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. Substantially the same results are observed in the bent surface region of the negative electrode.

[0327] In Figure 11b, graph (a) shows the results of counting the number of layers of subsections along the radial direction in the folded surface region F for Examples 2-1 to 2-5, graph (b) for Examples 3-1 to 3-4, graph (c) for Examples 4-1 to 4-3, and graph (d) for Examples 5-1 and 5-2.

[0328] Referring to Figure 11b, the uniform stacking interval b1 of the segmental intercepts appears in common in all examples. The uniform stacking interval b1 is the radius interval of the flattened region in the graph. The length of the uniform stacking interval b1 is equal to the maximum height h of the segmental intercepts when the minimum height h1 of the segmental intercepts is the same. N It increases as the decrease in the number of layers decreases. Also, the length of the uniform layering interval b1 is equal to the maximum height of the subsection h. N When these are the same, the number of layers of the subsection increases as the minimum height h1 of the subsection decreases. On the other hand, in the uniform layering interval b1, the number of layers of the subsection is equal to the maximum height h of the subsection. N The value increases as the value increases. In the example, a section b2 with a decreasing number of layers appears adjacent to a section b1 with a uniform number of layers.

[0329] In the example, the number of layers of the segment in the uniform layer number section b1 is 10 or more in all cases. Preferably, the region where the number of layers of the segment is 10 or more can be set as a preferred welding target region.

[0330] In the examples, the uniform layer count section b1 starts from the radius point where the variable height section of the segment (circle 2 in Figure 10) begins. In Examples 2-1 to 2-5, the variable height section of the segment (circle 2 in Figure 10) starts at 6 mm and extends outward. In Examples 3-1 to 3-4, the variable height section of the segment (circle 2 in Figure 10) starts at 7 mm and extends outward. In Examples 4-3 to 4-3, the variable height section of the segment (circle 2 in Figure 10) starts at 8 mm and extends outward. In Examples 5-1 and 5-2, the variable height section of the segment (circle 2 in Figure 10) starts at 9 mm and extends outward.

[0331] Table 7 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 layer count section to the length from the radius point where the uniform layer count section begins (6mm, 7mm, 8mm, 9mm) to the outermost point of the electrode assembly (22mm), and the ratio (d / f) of the length of the variable segment height section (circle 2) to the length from the radius point where the uniform layer count section begins (6mm, 7mm, 8mm, 9mm) to the outermost point of the electrode assembly (22mm).

[0332] [Table 7]

[0333] Referring to Examples 2-5, 3-4, 4-3, and 5-2 in Table 5, along with Figures 10 and 11b, the maximum height h of the segment in the segment height variable section (circle 2) is shown. NAlthough the height is the same at 10 mm, the minimum height h1 of the segment increases by 1 mm each time, from 4 mm, 5 mm, 6 mm, to 7 mm, while the length of the height-variable section (circle 2) decreases by 1 mm each time, from 6 mm, 5 mm, 4 mm, to 3 mm. In the four examples, the ratio of the uniform number of layers section (e / f) is highest in Example 2-5 at 69% and lowest in Example 5-1 at 31%, and the number of layers in the uniform number of layers section is the same in all examples. From the results shown in Table 7, the maximum height h of the segment N When these values ​​are the same, it can be seen that as the minimum height h1 of the subsection decreases and the width of the variable height subsection section (circle 2) increases, the width of the uniform stacking section also increases proportionally. The reason for this is that the smaller the minimum length h1 of the subsection, the closer the radius point where the subsection begins is to the core, and the region where the subsections are stacked expands towards the core.

[0334] Referring to Table 7, it can be seen that the number of layers of segmentation segments ranges from 16 to 27, the ratio of the segmentation segment with variable height (circle 2) (d / f) is 13% to 38%, and the ratio of the segmentation segment with a uniform number of layers (e / f) is 31% to 69%. Furthermore, the ratio of the segmentation segment omitted section (c) to the radius of the electrode assembly excluding the core (ba) (c / (ba)) is 20% to 35%. In addition, the ratio of the length of the electrode region corresponding to the segmentation segment omitted section to the total 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 total length of the electrode is 6% to 25%, and the ratio of the length of the electrode region corresponding to the height uniform section to the total length of the electrode is 62% to 81%.

[0335] Cylindrical batteries with the 1865 or 2170 form factor have an electrode assembly radius of approximately 9mm to 10mm. Therefore, as in the embodiment, it is not possible to ensure a radial length of 13mm to 16mm for the segment section (f), and it is not possible to ensure a length of approximately 4mm to 7mm for the segment omission section (c) while simultaneously ensuring a length of 5mm to 11mm for the uniform number of stacked segments (e) where the number of stacked segments is 10 or more. In conventional cylindrical batteries, if the core radius is designed to be the same as in the embodiment (2mm), the radial section in which segment sections can be placed is effectively only 7mm to 8mm. Furthermore, in conventional cylindrical batteries, the length of the electrodes in the winding direction is in the range of 600mm to 980mm. Such short electrode lengths are only about 15% to 24% of the electrode lengths in the embodiment (positive electrode 3948mm, negative electrode 4045mm). Therefore, the numerical ranges for parameters h, i, and j cannot be easily derived from the design specifications of conventional cylindrical batteries.

[0336] Next, in the section with variable segment height (circle 2 in Figure 10), the minimum height h1 and maximum height h N When the core diameter C of the electrode assembly is the same, we will explain, with specific examples, how the number of stacked segments changes along the radial direction of the bent surface region F depending on the core diameter C of the electrode assembly.

[0337] 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 in the height-variable section of segment 61 (circle 2 in Figure 10) is the same as 3 mm, and the maximum height h of the segment is the same. N The width was varied from 5 mm to 10 mm in 1 mm increments. Therefore, in the electrode assemblies of Examples 6-1 to 6-6, the width of the variable section height section (circle 2 in Figure 10) is 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm, respectively, and the section omitted section (circle 1 in Figure 10) is a radius section from 4 mm to 7 mm.

[0338] The electrode assemblies of Examples 7-1 to 7-6 have a radius of 22 mm, and the radius of core C is 2 mm. The minimum height h1 of the segment in the height-variable section of segment 61 (circle 2 in Figure 10) is the same as 3 mm, and the maximum height h of the segment is the same. N The width was varied from 5 mm to 10 mm in 1 mm increments. Therefore, in the electrode assemblies of Examples 7-1 to 7-6, the width of the variable section height section (circle 2 in Figure 10) is 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm, respectively, and the section omitted section (circle 1) is the same as the radius section from 2 mm to 5 mm.

[0339] Figure 11c is a graph showing the results of counting the number of stacked segments measured along the radial direction in the bent 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 Examples 7-1 to 7-6. Substantially the same results are observed in the bent surface region of the negative electrode.

[0340] In Figure 11c, graph (a) shows the results of counting the number of layers of subsections measured along the radial direction in the folded surface region F for Examples 6-1 to 6-6, and graph (b) shows the results for Examples 7-1 to 7-6.

[0341] Referring to Figure 11c, the uniform stacking interval b1 of the segmental intercepts appears in common in all examples. The uniform stacking interval b1 is the radial interval of the flattened region in the graph. The radial length of the uniform stacking interval b1 is equal to the maximum height h of the segmental intercepts when the minimum height h1 of the segmental intercepts is the same. N It increases as decreases. On the other hand, in the uniform layer number interval b1, the number of layers of the subsection is the maximum height of the subsection h N The value increases as the value increases. In the example, a section b2 with a decreasing number of layers is observed adjacent to a section b1 with a uniform number of layers.

[0342] In the example, the number of layers of the segment in the uniform layer number section b1 is 10 or more in all cases. Preferably, the region where the number of layers of the segment is 10 or more can be set as a preferred welding target region.

[0343] In the examples, the uniform layering interval b1 begins at the radius point where the variable-height section of the segment (circle 2 in Figure 10) begins. In Examples 6-1 to 6-6, the radius at which the variable-height section of the segment (circle 2 in Figure 10) begins is 7 mm, and in Examples 7-1 to 7-6, the radius at which the variable-height section of the segment (circle 2 in Figure 10) begins is 5 mm.

[0344] Table 8 below shows the calculation results for 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 layer count section to the length from the radius point where the uniform layer count section begins (7 mm, 5 mm) to the outermost point of the electrode assembly (22 mm), and the ratio (d / f) of the length of the variable-height section of the segment (circle 2) to the length from the radius point where the uniform layer count section begins (7 mm, 5 mm) to the outermost point of the electrode assembly (22 mm).

[0345] [Table 8]

[0346] Referring to Figure 10 and Examples 6-6 and 7-6 in Table 8, the minimum height h1 and maximum height h of the segment in the segment height variable section (circle 2) NThese are the same at 3 mm and 10 mm, respectively. However, the core radius of Example 6-6 is 2 mm larger than that of Example 7-6. Therefore, in Example 6-6, the uniform layer count section (e) and the segment section (f) are 2 mm smaller than in Example 7-6, while the number of layers of segment sections in the uniform layer count section is the same. This result is due to the difference in core radius. From the results shown in Table 8, it can be seen that when the width of the height-variable section of segment sections (circle 2) is the same, the smaller the core radius (a), the smaller the ratio of the height-variable section (circle 2) (d / f), while the ratio of the uniform layer count section (e / f) increases. Referring to Table 8, it can be seen that the number of layers of segment sections is 13 to 27, the ratio of the height-variable section of segment sections (circle 2) (d / f) is 12% to 47%, and the ratio of the length of the uniform layer count section (e / f) is 40% to 76%. Furthermore, the ratio of the segment omission section (c) to the radius (ba) of the electrode assembly excluding the core (c / (ba)) is 15% to 17%. Also, the ratio of the length of the electrode region corresponding to the segment omission section to the total length of the electrode is 6%, the ratio of the length of the electrode region corresponding to the height-variable section to the total length of the electrode is 7% to 32%, and the ratio of the length of the electrode region corresponding to the height-uniform section (circle 3) to the total length of the electrode is 59% to 83%.

[0347] Cylindrical batteries with the 1865 or 2170 form factor have an electrode assembly radius of approximately 9mm to 10mm. Therefore, as in the embodiment, it is not possible to secure a radial length of 15mm to 17mm for the segment section (f), and it is not possible to secure a length of approximately 3mm for the segment omission section (c) while simultaneously securing a length of 6mm to 13mm for the uniform stacking section (e) where the number of stacked segments is 10 or more. In conventional cylindrical batteries, if the core radius is designed to be the same as in the embodiment (2mm to 4mm), the radial section in which segment sections can be placed is effectively only 5mm to 8mm. Furthermore, in conventional cylindrical batteries, the length of the electrodes in the winding direction is in the range of 600mm to 980mm. Such short electrode lengths are only about 15% to 24% of the electrode lengths in the embodiment (positive electrode 3948mm, negative electrode 4045mm). Therefore, the numerical ranges for parameters h, i, and j cannot be easily derived from the design specifications of conventional cylindrical batteries.

[0348] Considering the data in Tables 6 to 8 comprehensively, the number of layers of segmental segments in the uniform segmental segmental segment section can be 11 to 27. Also, the ratio (d / f) of the segmental segmental segment with variable height (circle 2) can be 6% to 47%. Also, the ratio (e / f) of the uniform segmental segment section can be 31% to 82%. Also, the ratio (c / (ba)) of the length of the segmental segment omitted section to the radius of the electrode assembly excluding the core can be 15% to 35%. Also, the ratio of the length of the electrode region corresponding to the segmental segment omitted section to the total length of the electrode (length in the winding direction) can be 6% to 20%. Also, the ratio of the length of the electrode region corresponding to the segmental segmental segment with variable height to the total length of the electrode can be 3% to 32%. Also, the ratio of the length of the electrode region corresponding to the segmental segmental segment with uniform height to the total length of the electrode can be 59% to 87%.

[0349] On the other hand, the parameters described in Tables 6 to 8 are: core radius (a); electrode assembly radius (b); minimum height h1 and maximum height h in the variable section of the segment height. N ;The change in segment height Δh per 1 mm increase in radius; this can vary depending on design factors including the thickness of the positive electrode, negative electrode, and separation membrane.

[0350] Therefore, the number of layers of subsections in the uniform layering section can be extended from 10 to 35. The ratio of the variable-height section of subsections (d / f) can be extended from 1% to 50%. The ratio of the uniform layering section (e / f) can be extended from 30% to 85%. The ratio of the length of the subsection-omitted section to the radius of the electrode assembly excluding the core (c / (ba)) can be extended from 10% to 40%. The ratio of the length of the electrode region corresponding to the subsection-omitted section to the total length of the electrode (length in the winding direction) can be extended from 1% to 30%. The ratio of the length of the electrode region corresponding to the variable-height section of subsections to the total length of the electrode can be extended from 1% to 40%. The ratio of the length of the electrode region corresponding to the uniform-height section of subsections to the total length of the electrode can be extended from 50% to 90%.

[0351] In the bent surface regions F formed on the upper and lower parts of the electrode assembly, the uniform layer count section can be used as a welding target region for the current collector.

[0352] Preferably, the welding region of the current collector overlaps with the uniform layering section of the electrode assembly by at least 50% in the radial direction, and a higher overlap ratio is even more preferable.

[0353] Preferably, other regions of the current collector's welding area that do not overlap with the uniform layer count section may overlap with the decreasing layer count section adjacent to the uniform layer count section in the radial direction.

[0354] More preferably, other regions of the current collector's welding area that do not overlap with the uniform layer count section may overlap with regions of the decreasing layer count section where the number of overlapping segments is 10 or more.

[0355] Welding the current collector to a region with 10 or more layers of segmentation is preferable in terms of weld strength and the ability to prevent damage to the separation film and active material layer during welding. This is particularly useful when welding the current collector using a high-power laser with high transmission characteristics.

[0356] When a current collector is welded with a laser to a section with a uniform number of layers, where 10 or more sections are stacked, even if the laser output is increased to improve welding quality, the section with a uniform number of layers absorbs almost all of the laser energy and forms weld beads. This prevents the separation film and active material layer below the bent surface region F from being damaged by the laser.

[0357] Furthermore, because the laser-irradiated area has 10 or more layers of segmented material, welding beads are formed with sufficient volume and thickness. Therefore, sufficient welding strength is ensured, and the resistance at the welding interface can be reduced to a level suitable for rapid charging.

[0358] The laser output during welding of the current collector can be determined by the desired welding strength between the bent surface region F and the current collector. The welding strength increases proportionally to the number of layers of segmentation. This is because the volume of welding beads formed by the laser increases as the number of layers increases. Welding beads are formed as the current collector material and the segmentation material are melted together. Therefore, a larger volume of welding beads results in a stronger bond between the current collector and the bent surface region, and a lower contact resistance at the welding interface.

[0359] Preferably, the weld strength is 2 kgf / cm². 2 More preferably 4 kgf / cm² 2 The above is possible. Furthermore, the welding strength is preferably 8 kgf / cm². 2 The following is more like 6 kgf / cm² 2 It can be set as follows:

[0360] If the welding strength meets the above numerical range, the physical properties of the weld interface will not deteriorate even if the electrode assembly is subjected to severe vibration along the winding axis and / or radial direction, and the resistance of the weld interface can also be reduced because the volume of welding beads is sufficient.

[0361] 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 40% to 90% of the maximum laser output specifications provided by the device.

[0362] Weld strength is the tensile force per unit area (kgf / cm²) of the current collector when the current collector begins to separate from the bent surface region F. 2 It can be defined as follows: Specifically, after the welding of the current collector is completed, a tensile force is applied to the current collector, and its magnitude is gradually increased. When the tensile force exceeds a critical value, the intercepts begin to separate from the weld interface. At this point, the value obtained by dividing the tensile force applied to the current collector by the area of ​​the current collector corresponds to the weld strength.

[0363] The bent surface region F is composed of multiple layers of segmented sections, and according to the embodiment described above, the number of layered segmented sections can be increased from a minimum of 10 to a maximum of 35.

[0364] The thickness of the positive electrode current collector (foil) is 10 μm to 25 μm, and the thickness of the negative electrode current collector (foil) can be selected in the range of 5 μm to 20 μm. Therefore, the bent surface region F of the positive electrode may include a region where the total stacking thickness of the segmented sections is 100 μm to 875 μm. Similarly, the bent surface region F of the negative electrode may include a region where the total stacking thickness of the segmented sections is 50 μm to 700 μm.

[0365] Figure 12 is a top view of an electrode assembly showing a uniform layer number section b1 and a decreasing layer number section b2 in the bent surface region F formed by the section 61 included in the section alignment section 66 according to an embodiment of the present invention.

[0366] Referring to Figure 12, the bent surface region F of the segment 61 is formed as the segment 61 included in the segment alignment section 66 is bent toward the core C of the electrode assembly JR. In Figure 12, the region between the two circles indicated by the dashed line corresponds to the uniform number of layers section 61 section b1, where the number of layers of segment 61 is 10 or more, and the region outside the uniform number of layers section b1 corresponds to the decreasing number of layers section b2.

[0367] As an example, current collector Pc If the segmented segments 61 of the segmented segment alignment section 66 are welded to the bent surface region F formed while being bent, the current collector P c Weld pattern W on the surface p This is generated. Weld pattern W p This can be an arrangement of line patterns or dot patterns. Welding pattern W p This corresponds to the welding area and can overlap by 50% or more with the uniform layer number section b1 along the radial direction. Therefore, welding pattern W p A portion of the weld pattern is included in the uniform layer number section b1, and the remaining weld pattern W p This may be included in the section b2 where the number of layers decreases, outside the section b1 where the number of layers is uniform. Of course, the welding pattern W p The entire structure can overlap with the uniform layering interval b1.

[0368] Preferably, current collector P c The end of the portion that contacts the bent surface region F may cover the end of the segment 61 that was bent towards the core C in the last winding turn. In this case, the segment 61 covers the current collector P c Weld pattern W while pressed down p As a result of the formation of the current collector P c The bending surface region F is strongly bonded to the weld surface region. As a result, the segmented sections 61 stacked in the winding axis direction are tightly bonded to each other, which reduces the resistance at the welding interface and prevents the segmented sections 61 from lifting up.

[0369] On the other hand, the bending direction of the segment may be opposite to the direction described above. That is, the segment may be bent from the core side to the outer circumference side. In this case, the pattern in which the height of the segment segments 61 included in the segment segment group 61g changes along the winding direction (X-axis direction) may be opposite to that of the embodiment (modified form) described above. For example, the height of the segment segments 61 may decrease in stages from the core to the outer circumference side. Also, the structure applied to the first part B1 and the structure applied to the second part B3 can be substituted for each other. Preferably, the height change pattern of the segment segments can be designed such that the height of the segment segments 61 decreases in stages from the core side to the outer circumference side, and when the segment segment 61 closest to the outer circumference of the electrode assembly is bent to the outer circumference side, the end of the segment segment 61 does not protrude outside the outer circumference of the electrode assembly.

[0370] The electrode structure of the above-described embodiment (modified form) can be applied to at least one of the first and second electrodes with different polarities included in a jelly roll-type electrode assembly. Furthermore, when the electrode structure of the embodiment (modified form) is applied to one of the first and second electrodes, a conventional electrode structure may be applied to the other. In addition, the electrode structures applied to the first and second electrodes may not be the same, but may be different.

[0371] As an example, when the first electrode and the second electrode are the positive and negative electrodes, one of the embodiments (modified forms) may be applied to the first electrode, and a conventional electrode structure (see Figure 1) may be applied to the second electrode.

[0372] As another example, when the first electrode and the second electrode are a positive electrode and a negative electrode, one of the embodiments (modified forms) may be selectively applied to the first electrode, and one of the embodiments (modified forms) may be selectively applied to the second electrode.

[0373] 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 can be any active material known in the industry without limitation.

[0374] For example, the positive electrode active material is a material with the general chemical formula A[Ax M y ]O 2+z The compound may contain alkali metal compounds represented as follows: (A contains at least one element from Li, Na, and K; M contains 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; stoichiometric coefficients x, y, and z are selected so that the compound maintains electrical neutrality).

[0375] As another example, the positive electrode active material is an alkali metal compound xLiM disclosed in U.S. Patent No. 6,677,082, U.S. Patent No. 6,680,143, etc. 1 O2-(1-x)Li2M 2 O3(M 1 It contains at least one element having an average oxidation state of 3; M 2 It may contain at least one element having an average oxidation state of 4 (0 ≤ x ≤ 1).

[0376] As yet 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 It contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg and Al; M 2 It 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 3contains 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 can be a lithium metal phosphate represented by Li3M2(PO4)3 [M contains at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg, and Al].

[0377] Preferably, the positive electrode active material may contain primary particles and / or secondary particles formed by aggregation of primary particles.

[0378] 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 with 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.

[0379] As the separation membrane, a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., can be used alone or by laminating these. As another example, the separation membrane can use a normal porous non-woven fabric, for example, a non-woven fabric made of high-melting-point glass fibers, polyethylene terephthalate fibers, etc.

[0380] At least one surface of the separation membrane may include a coating layer of inorganic particles. Also, the separation membrane itself may consist of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure bonded to a binder so that an interstitial volume exists between adjacent particles.

[0381] The inorganic particles can be made of an inorganic substance with a dielectric constant of 5 or more. As a non-limiting example, the inorganic particles are Pb(Zr,Ti)O3 (PZT), Pb 1-x Lax ZR 1-y Ti y O3(PLZT), PB(Mg3Nb) 2 / 3 It may contain at least one substance selected from the group consisting of O3-PbTiO3(PMN-PT), BaTiO3, hafnia (HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO, and Y2O3.

[0382] The structure of an electrode assembly according to one embodiment of the present invention will be described in detail below.

[0383] Figure 13 is a cross-sectional view of a jelly roll-type electrode assembly 100, in which the electrodes 60 of the embodiment are applied as 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 66.

[0384] Referring to Figure 13, the plain 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.

[0385] The height of the plain portion of the first part B1 is relatively smaller than the height of the segment 61. Also, in the third part B2, the fold length of the innermost segment 61 is the same as or shorter than the radial length R of the first part B1. The fold length H corresponds to the distance from the point where the innermost segment 61 is folded to the upper end of the segment 61. In the modified example, the fold length H may be smaller than the sum of the radial length R of the winding turn formed by the first part B1 and 10% of the radius of the core 102.

[0386] Therefore, even if the segment 61 included in the segment alignment section 66 is bent, more than 90% of the diameter of the core 102 of the electrode assembly 100 remains open to the outside. The core 102 is a cavity at the center of the electrode assembly 100. If the core 102 is not blocked, the electrolyte injection process is not hindered, and the efficiency of electrolyte injection is improved. In addition, a welding jig can be inserted through the core 102 to facilitate the welding process between the current collector on the negative electrode (or positive electrode) side and the battery housing (or rivet terminal).

[0387] The height of the plain portion of the second section B3 is relatively lower than the height of the segment 61. Therefore, it is possible to prevent the phenomenon of an internal short circuit occurring when the beading portion of the battery housing comes into contact with the upper edge of the electrode assembly 100 during the process in which the beading portion of the battery housing is pressurized near the winding turn of the second section B3.

[0388] In one modified example, the second part B3 may include segmental segments 61 that form the segmental segment alignment section 66, and the height of the segmental segments 61 of the second part B3 may decrease gradually or in steps, unlike in the illustration in Figure 13. Also, in Figure 13, the height of the segmental segments 61 of the segmental segment alignment section 66 is equal in a portion of the outer periphery, but the height of the segmental segments 61 of the segmental segment alignment section 66 may increase gradually or in steps from the boundary between the first part B1 and the third part B2 to the boundary between the third part B2 and the second part B3. The section in the segmental segment alignment section 66 where the height of the segmental segments 61 changes corresponds to the segmental segment height variable section (circle 2 in Figure 10).

[0389] The second blank portion 43b has the same structure as the first blank portion 43a. In one modified example, the second blank portion 43b may have a conventional electrode structure or an electrode structure of another embodiment (modified form).

[0390] The end portion 101 of the segment 61 included in the segment alignment section 66 can be bent radially from the electrode assembly 100, for example, from the outer circumference to the core. In this case, the plain portions of the first section B1 and the second section B3 are not substantially bent.

[0391] Since the segment alignment section 66 includes multiple segment segments 61 arranged in the radial direction, the bending stress is relieved, preventing the plain sections 43a and 43b near the bending point from tearing or becoming abnormally deformed. Furthermore, when the width and / or height and / or spacing pitch of the segment segments 61 are adjusted within the numerical range of the above-described embodiment, the segment segments 61 overlap in sufficient quantities to ensure sufficient welding strength while being bent toward the core, and do not form any gaps in the bending surface region F.

[0392] Figure 14 is a cross-sectional view of an electrode assembly 110 according to yet another embodiment of the present invention, cut along the Y-axis direction (winding axis direction) so as to pass through the segment alignment section 66.

[0393] Referring to Figure 14, the electrode assembly 110 is substantially identical to the electrode assembly 100 in Figure 13, except that the second part B3 also includes segmentation segments 61 that form the segmentation segment alignment section 66, and the height of the segmentation segments 61 of the second part B3 is substantially the same as the height of the outermost segmentation segments 61 of the third part B2.

[0394] In the electrode assembly 110, the height of the plain portion of the first part B1 is relatively lower than the height of the segment 61 included in the segment alignment portion 66. Also, the bend length H of the innermost segment 61 in the segment alignment portion 66 is the same as or shorter than the radial length R of the winding turn formed by the first part B1. Preferably, the winding turn formed by the first part B1 may be a segment-omitted section without segment segments (circle 1 in Figure 10). In a modified example, the bend length H may be smaller than the sum of the radial length R of the winding turn formed by the first part B1 and 10% of the radius of the core 112.

[0395] Therefore, even if the segment 61 included in the segment alignment section 66 is bent, more than 90% of the diameter of the core 112 of the electrode assembly 110 remains open to the outside. If the core 112 is not blocked, there is no interference with the electrolyte injection process, and the efficiency of electrolyte injection is improved. In addition, a welding jig can be inserted through the core 112 to easily perform the welding process between the current collector on the negative electrode (or positive electrode) side and the battery housing (or rivet terminal).

[0396] In one modified example, the structure in which the height of the segment 61 included in the segment alignment section 66 gradually or stepwise increases from the core side to the outer circumference side can be extended to the winding turn formed by the second section B3. In this case, the height of the segment 61 included in the segment alignment section 66 can gradually or stepwise increase from the boundary between the first section B1 and the third section B2 to the outermost surface of the electrode assembly 110.

[0397] The second blank portion 43b has the same structure as the first blank portion 43a. In one modified example, the second blank portion 43b may have a conventional electrode structure or an electrode structure of another embodiment (modified form).

[0398] The end portion 111 of the segment 61 included in the segment alignment section 66 can be bent radially from the electrode assembly 110, for example, from the outer circumference to the core. In this case, the plain portion of the first section B1 is not substantially bent.

[0399] Since the segment alignment section 66 includes multiple segment segments 61 arranged in the radial direction, the bending stress is relieved, preventing the plain sections 43a and 43b near the bending point from tearing or becoming abnormally deformed. Furthermore, when the width and / or height and / or spacing pitch of the segment segments 61 are adjusted within the numerical range of the above-described embodiment, the segment segments 61 overlap in sufficient quantities to ensure sufficient welding strength while being bent toward the core, and do not form any gaps in the bending surface region.

[0400] Figure 15 is a cross-sectional view of an electrode assembly 120 according to yet another embodiment of the present invention, cut along the Y-axis direction (winding axis direction) so as to pass through the segment alignment section 66.

[0401] Referring to Figure 15, the electrode assembly 120 is substantially identical to the electrode assembly 100 in Figure 13, except that the height of the segment 61 included in the segment alignment section 66 gradually or stepwise increases and then decreases. The radial section in which the height of the segment 61 changes can be considered as the segment height variable section (circle 2 in Figure 10). In this case as well, the segment height variable section of the segment 61 can be designed such that a uniform stacking section, where the number of stacked segments of the segment 61 is 10 or more, appears in the bent surface region F formed as the segment 61 is bent, within the preferred numerical range described above.

[0402] In the electrode assembly 120, the height of the plain portion of the first part B1 is relatively lower than the height of the segment 61. Also, the bend length H of the segment 61 closest to the core 122 is the same as or shorter than the radial length R of the winding turn formed by the first part B1. The section corresponding to the winding turn formed by the first part B1 corresponds to the segment omission section (circle 1 in Figure 10) where there is no segment. In the modified example, the bend length H may be smaller than the sum of the radial length R of the winding turn formed by the first part B1 and 10% of the radius of the core 102.

[0403] Therefore, even if the segment 61 included in the segment alignment section 66 is bent toward the core, more than 90% of the diameter of the core 122 of the electrode assembly 120 remains open to the outside. If the core 122 is not blocked, there is no interference with the electrolyte injection process, and the efficiency of electrolyte injection is improved. Furthermore, a welding jig can be inserted through the core 122 to facilitate the welding process between the negative electrode (or positive electrode) side current collector and the battery housing (or rivet terminal).

[0404] Furthermore, the height of the plain portion of the second portion B3 is relatively lower than the height of the segment 61, and preferably, segment 61 may not be formed on the second portion B3. Therefore, it is possible to prevent the phenomenon of internal short circuits occurring when the beading portion of the battery housing is pressurized near the winding turns formed by the second portion B3, while the beading portion and the periphery of the electrode assembly 120 come into contact with each other. In one modified example, the second portion B3 may include segment slits that form the segment slit alignment portion 66, and the height of the segment slits of the second portion B3 may decrease gradually or in steps toward the outer circumference.

[0405] The second blank portion 43b has the same structure as the first blank portion 43a. In modified examples, the second blank portion 43b may have a conventional electrode structure or an electrode structure of another embodiment (modified form).

[0406] The end portion 121 of the segment 61 included in the segment alignment section 66 can be bent from the outer circumference side of the electrode assembly 120 toward the core side. At this time, the plain portions of the first section B1 and the second section B3 are not substantially bent.

[0407] Since the segment alignment section 66 includes multiple segment segments 61 arranged in the radial direction, bending stress is relieved, preventing the plain sections 43a and 43b from tearing or deforming abnormally. Furthermore, when the width and / or height and / or spacing pitch of the segment segments 61 are adjusted within the numerical range of the above-described embodiment, the segment segments 61 overlap in sufficient quantities to ensure sufficient welding strength while being bent toward the core, and no gaps are formed in the bent surface region F.

[0408] Figure 16 is a cross-sectional view of an electrode assembly 130 according to yet another embodiment of the present invention, cut along the Y-axis direction (winding axis direction) so as to pass through the segment alignment section 66.

[0409] Referring to Figure 16, the electrode assembly 130 is substantially identical to the electrode assembly 120 in Figure 15, except that the second portion B3 includes segmental segments 61 that form a segmental segment alignment portion 66, and the height of the segmental segments 61 has a pattern in which it gradually or stepwise decreases from the boundary point between the second portion B3 and the third portion B2 toward the outermost surface of the electrode assembly 130.

[0410] In the electrode assembly 130, the height of the plain portion of the first part B1 is relatively lower than the height of the segment 61. Also, the bend length H of the segment 61 closest to the core 132 is the same as or shorter than the radial length R of the winding turn formed by the first part B1. The winding turn formed by the first part B1 corresponds to the segment omission section (circle 1 in Figure 10) where there is no segment. In the modified example, the bend length H may be smaller than the sum of the radial length R of the winding turn formed by the first part B1 and 10% of the radius of the core 102.

[0411] Therefore, even if the segment 61 included in the segment alignment section 66 is bent toward the core, more than 90% of the diameter of the core 132 of the electrode assembly 130 remains open to the outside. If the core 132 is not blocked, there is no interference with the electrolyte injection process, and the efficiency of electrolyte injection is improved. In addition, a welding jig can be inserted through the core 132 to easily perform the welding process between the current collector on the negative electrode (or positive electrode) side and the battery housing (or rivet terminal).

[0412] The second blank portion 43b has the same structure as the first blank portion 43a. In one modified example, the second blank portion 43b may have a conventional electrode structure or an electrode structure of another embodiment (modified form).

[0413] The end portion 131 of the segment 61 included in the segment alignment section 66 can be bent from the outer circumference side of the electrode assembly 130 toward the core side. In this case, the plain portion of the first section B1 is not substantially bent.

[0414] Since the segment alignment section 66 includes multiple segment segments 61 arranged in the radial direction, the bending stress is relieved, preventing the plain sections 43a and 43b near the bending point from tearing or becoming abnormally deformed. Furthermore, when the width and / or height and / or spacing pitch of the segment segments 61 are adjusted within the numerical range of the above-described embodiment, the segment segments 61 overlap in sufficient quantities to ensure sufficient welding strength while being bent toward the core, and do not form any gaps in the bending surface region F.

[0415] On the other hand, in the above-described embodiment (modified form), the ends of the segment segments 61 included in the segment segment alignment section 66 may be bent from the core side to the outer circumference side. In this case, it is preferable that the winding turn formed by the second section B3 is designed as a segment segment omitted section (circle 1 in Figure 10) without segment segments and is not bent to the outer circumference side. Furthermore, the radial width of the winding turn formed by the second section B3 may be the same as or greater than the length to which the outermost segment segment is bent. This prevents the end of the bent portion from protruding beyond the outer surface of the electrode assembly toward the inner surface of the battery housing when the outermost segment segment is bent toward the outer circumference side. Also, the structural change pattern of the segment segments included in the segment segment alignment section 66 may be the opposite of that in the above-described embodiment (modified form). For example, the height of the segment segments may increase stepwise or gradually from the core side toward the outer circumference side. In other words, by arranging sections with omitted segments (circle 1 in Figure 10), sections with variable segment height (circle 2 in Figure 10), and sections with uniform segment height (circle 3 in Figure 10) sequentially from the outer circumference to the core side of the electrode assembly, a section with a uniform number of layers, where the number of layers of segments is 10 or more, may appear in the bent surface region F within a preferred numerical range.

[0416] The diverse electrode assembly structures according to the embodiments of the present invention can be applied to jelly roll-type cylindrical batteries.

[0417] Preferably, the cylindrical battery may be a cylindrical battery with a form factor ratio (defined as the ratio of the diameter to the height of the cylindrical battery, i.e., the ratio of height (H) to relative diameter (Φ)) greater than approximately 0.4. Here, the form factor refers to the values ​​indicating the diameter and height of the cylindrical battery.

[0418] Preferably, the diameter of the cylindrical battery may be 35 mm or more, preferably 40 mm to 50 mm. The height of the cylindrical battery may be 70 mm or more, preferably 75 mm to 90 mm. A cylindrical battery according to one embodiment may be, for example, a 46110 battery, a 4875 battery, a 48110 battery, a 4880 battery, or a 4680 battery. In the numerical value indicating the form factor, the first two digits indicate the diameter of the battery, and the remaining digits indicate the height of the battery.

[0419] When an electrode assembly with a tabless structure is applied to a cylindrical battery with a form factor ratio exceeding 0.4, the stress applied radially when bending the plain section is large, making the plain section prone to tearing. Furthermore, when welding a current collector to the bent surface region of the plain section, the number of layers of the plain section in the bent surface region must be sufficiently increased in order to ensure sufficient welding strength and reduce resistance. These requirements can be met by the electrode and electrode assembly according to an embodiment (modified form) of the present invention.

[0420] A battery according to one embodiment of the present invention may be a cylindrical battery that is substantially cylindrical in shape, with a diameter of approximately 46 mm, a height of approximately 110 mm, and a form factor ratio of 0.418.

[0421] A battery according to another embodiment may be a cylindrical battery that is substantially cylindrical in shape, with a diameter of approximately 48 mm, a height of approximately 75 mm, and a form factor ratio of 0.640.

[0422] Furthermore, another embodiment of the battery may be a cylindrical battery that is substantially cylindrical in shape, with a diameter of approximately 48 mm, a height of approximately 110 mm, and a form factor ratio of 0.436.

[0423] Furthermore, a battery according to another embodiment may be a cylindrical battery that is substantially cylindrical in shape, with a diameter of approximately 48 mm, a height of approximately 80 mm, and a form factor ratio of 0.600.

[0424] Furthermore, a battery according to another embodiment may be a cylindrical battery that is substantially cylindrical in shape, with a diameter of approximately 46 mm, a height of approximately 80 mm, and a form factor ratio of 0.575.

[0425] Traditionally, 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. In the case of an 1865 battery, the diameter is approximately 18mm, the height is approximately 65mm, and the form factor ratio is 0.277. In the case of a 2170 battery, the diameter is approximately 21mm, the height is approximately 70mm, and the form factor ratio is 0.300.

[0426] The following describes in detail a cylindrical battery according to an embodiment of the present invention.

[0427] Figure 17 is a cross-sectional view of a cylindrical battery 190 according to one embodiment of the present invention, obtained by cutting along the Y-axis direction so as to pass through the bent surface region (F in Figure 7g) of the segment included in the segment alignment section (66 in Figure 7g).

[0428] Referring to Figure 17, a cylindrical battery 190 according to one embodiment of the present invention includes an electrode assembly 110 comprising a first electrode, a separator membrane, and a second electrode, a battery housing 142 housing the electrode assembly 110, and a sealant 143 sealing the open end of the battery housing 142.

[0429] The battery housing 142 is a cylindrical container with an opening formed at the top. The battery housing 142 is made of a conductive metallic 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 houses the electrode assembly 110 in its inner space through the upper opening, and also houses the electrolyte together with it.

[0430] Electrolytes are, A + B - It can be a salt with a structure like this. Here, A + Li + kaNa + , K + It contains alkali metal cations such as, or ions consisting of combinations thereof. And, B - 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 - It contains one or more anions selected from the group consisting of the following.

[0431] Furthermore, electrolytes may be used after being dissolved in an organic solvent. Suitable organic solvents include 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 mixtures thereof.

[0432] The electrode assembly 110 may have a jelly-roll structure. As shown in Figure 2, the electrode assembly 110 can be manufactured by winding a laminate formed by stacking a lower separation membrane, a first electrode, an upper separation membrane, and a second electrode in order at least once, with the winding center C as the reference point.

[0433] The first electrode and the second electrode have different polarities. That is, if one has positive polarity, the other has negative polarity. At least one of the first electrode and the second electrode may have an electrode structure according to the embodiment (modified form) described above. The other of the first electrode and the second electrode may have a conventional electrode structure or an electrode structure according to the embodiment (modified form). The electrode assembly 110 is not limited to one electrode pair, but may have two or more.

[0434] As shown in Figure 7f, the upper and lower parts of the electrode assembly 110 are provided with segment alignment sections (see 66 in Figure 7f) formed by segment segments contained in the first blank section 146a of the first electrode and the second blank section 146b of the second electrode, respectively.

[0435] The segments included in the segment alignment section 66 are bent radially in the electrode assembly 110, for example from the outer circumference to the core, forming a bent surface region F.

[0436] The first section B1 is shorter in height than the other sections and corresponds to the section a1 without a subsection, so it cannot be folded toward the core.

[0437] Preferably, the bent surface region F may include, in order from the core side to the outer circumference, a section with omitted segment a1, a section with variable segment height a2, and a section with uniform segment height a3.

[0438] As shown in Figures 11a, 11b, and 11c, the bent surface region F includes a section a1 where the section is omitted, and adjacent to it, a section b1 with a uniform number of layers where the number of layers of section is 10 or more.

[0439] The bent surface region F may also include a layer count reduction section b2 adjacent to the outer circumference of the electrode assembly 110, where the number of layers of segmentation decreases toward the outer circumference. Preferably, the uniform layer count section b1 may be set as a welding target region.

[0440] In the folded surface region F, the preferred numerical ranges for the ratio of the variable height section a2 of the segment (a2 / c), the ratio of the uniform number of layered segments b1 (b1 / c), and the ratio of the area of ​​the uniform number of layered segments b1 to the area of ​​the folded surface region F have been described above, so a repeated explanation will be omitted.

[0441] The first current collector 144 can be laser-welded to the bent surface region F of the first plain section 146a, and the second current collector 145 can be laser-welded to the bent surface region F of the second plain section 146b. The welding method can be replaced with ultrasonic welding, resistance welding, spot welding, etc.

[0442] Preferably, more than 50% of the welding area W of the first current collector 144 and the second current collector 145 may overlap with the uniform layer number section b1 of the bent surface area F. Optionally, the remaining area of ​​the welding area W may overlap with the decreasing layer number section b2 of the bent surface area F. It is more preferable for the entire welding area W to overlap with the uniform layer number section b1 in terms of high welding strength, low resistance at the welding interface, and prevention of damage to the separation film and active material layer.

[0443] Preferably, in the uniform layer count section b1 that overlaps with the welding region W, and in the selectively decreasing layer count section b2, the number of layers of the segment can be 10 to 35.

[0444] Selectively, if the number of layers in the segment of the layer count reduction section b2 that overlaps the welding area W is less than 10, the laser output in the layer count reduction section b2 may be lower than the laser output in the layer count uniform section b1. That is, when the welding area W overlaps simultaneously with the layer count uniform section b1 and the layer count reduction section b2, the laser output can be varied according to the number of layers in the segment. In this case, the welding strength in the layer count uniform section b1 may be greater than the welding strength in the layer count reduction section b2.

[0445] In the bent surface regions F formed on the upper and lower parts of the electrode assembly 110, the radial lengths of the segment omission section a1 and / or the segment height variable section a2 and / or segment height uniform section a3 may be the same or different.

[0446] Furthermore, the bent surface regions F formed on the upper and lower parts of the electrode assembly 110 can form a planar symmetrical structure. Therefore, when the upper bent surface region F is projected onto the lower bent surface region F, they can substantially overlap each other.

[0447] In the electrode assembly 110, the height of the plain portion of the first part B1 is relatively lower than that of the other parts. Also, as shown in Figure 14, the bend 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 part B1 and 10% of the radius of the core 112.

[0448] Therefore, even if the segmented segments included in the segmented segment alignment section 66 are bent toward the core, more than 90% 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, there is no interference with the electrolyte injection process, and the efficiency of electrolyte injection is improved. In addition, a welding jig can be inserted through the core 112 to facilitate the welding process between the second current collector 145 and the battery housing 142.

[0449] When the width and / or height and / or spacing pitch of the segmental sections are adjusted to satisfy the numerical range of the above-described embodiment, when the segmental sections are bent, they overlap to a sufficient degree to ensure sufficient welding strength, and do not form any gaps in the bent surface region F.

[0450] Preferably, the first current collector 144 and the second current collector 145 may have an outer diameter that covers the ends of the segmental segments (see 61 in Figure 12) that are bent in the final winding turn of the first and second electrodes. In this case, welding is possible with the segmental segments forming the bent surface region F uniformly pressed by the current collectors, and the tightly stacked state of the segmental segments can be maintained even after welding. A tightly stacked state means a state in which there are substantially no gaps between the segmental segments, as shown in Figure 10. A tightly stacked state contributes to reducing the resistance of the cylindrical battery 190 to a level suitable for rapid charging (e.g., 4 mΩ) or below.

[0451] The sealing body 143 may include a cap plate 143a, a first gasket 143b that provides airtightness and insulation between the cap plate 143a and the battery housing 142, and a connecting plate 143c that is electrically and mechanically coupled to the cap plate 143a.

[0452] The cap plate 143a is a component made of a conductive metallic 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 electrically insulated from the battery housing 142 through the first gasket 143b. Thus, the cap plate 143a can function as the first electrode terminal (e.g., positive electrode) of the cylindrical battery 190.

[0453] The cap plate 143a is placed on a beading portion 147 formed on the battery housing 142 and secured 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 projection 143d that protrudes upward from its center.

[0454] The battery housing 142 is electrically connected to the bent surface region F of the second electrode. Therefore, the battery housing 142 has the same polarity as the second electrode. If the second electrode has negative polarity, then the battery housing 142 also has negative polarity.

[0455] The battery housing 142 is provided with a beading portion 147 and a crimping portion 148 at its upper end. The beading portion 147 is formed by pressing around the outer circumferential surface of the battery housing 142. The beading portion 147 prevents the electrode assembly 110 housed inside the battery housing 142 from coming out of the upper end opening of the battery housing 142 and can function as a support portion on which the seal 143 is placed.

[0456] The second portion B3 of the first electrode does not include a segment and can be notched in the same way as the first portion B1. Preferably, the inner circumferential surface of the beading portion 147 is separated from the winding turns formed by the second portion B3 of the first electrode by a predetermined distance. 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 separated from the winding turns formed by the second portion B3 of the first electrode by a predetermined distance. Also, because the plain portion of the second portion B3 is low in height, the winding turns of the second portion B3 are not substantially affected when the battery housing 142 is pushed in from the outside to form the beading portion 147. Therefore, the winding turns of the second portion B3 are not compressed by other components such as the beading portion 147, thereby preventing partial deformation of the electrode assembly 110 and preventing internal short circuits in the cylindrical battery 190.

[0457] Preferably, if the indentation depth of the beading portion 147 is D1 and 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 is D2, then the relation "D1 ≤ D2" may be satisfied. In this case, when the battery housing 142 is pressed in to form the beading portion 147, damage to the winding turns formed by the second portion B3 is substantially prevented.

[0458] The crimping portion 148 is formed on the upper part of the beading portion 147. The crimping portion 148 has a shape that extends and bends to enclose the outer circumferential surface of the cap plate 143a, which is positioned on the beading portion 147, and a portion of the upper surface of the cap plate 143a.

[0459] The cylindrical battery 190 may further include a first current collector 144 and / or a second current collector 145 and / or an insulator 146.

[0460] The first current collector 144 is coupled to the upper part of the electrode assembly 110. The first current collector 144 is made of a conductive metallic material such as aluminum, copper, steel, or nickel, 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 collector 144. The lead 149 may extend above the electrode assembly 110 and be coupled to the connecting plate 143c, or it may be directly coupled to the lower surface of the cap plate 143a. The lead 149 may be coupled to other parts by welding.

[0461] Preferably, the first current collector 144 can 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.

[0462] The bonding of the first current collector 144 to the bent surface region F of the first electrode can be performed, for example, by laser welding. Laser welding can be performed in a manner that partially melts the base material of the current collector. In a modified example, the welding of the first current collector 144 to the bent surface region F can be performed with solder interposed. In this case, the solder may have a lower melting point than the first current collector 144 and the first blank portion 146a. Laser welding can be replaced by resistance welding, ultrasonic welding, spot welding, etc.

[0463] A second current collector 145 may be bonded to the lower surface of the electrode assembly 110. One surface of the second current collector 145 may be welded to the bent surface region F of the second electrode, and the other surface may be welded to the inner bottom surface of the battery housing 142. The bonding structure between the second current collector 145 and the bent surface region F of the second electrode may be substantially the same as the bonding structure between the first current collector 144 and the bent surface region F of the first electrode.

[0464] The insulator 146 can cover the first current collector 144. By covering the upper surface of the first current collector 144 with the insulator 146, direct contact between the first current collector 144 and the inner surface of the battery housing 142 can be prevented.

[0465] The insulator 146 is provided with a lead hole 151 through which a lead 149 extending upward from the first current collector 144 is drawn out. The lead 149 is drawn out upward through the lead hole 151 and coupled to the lower surface of the connecting plate 143c or the lower surface of the cap plate 143a.

[0466] The peripheral region of the insulator 146 is interposed between the first current collector 144 and the beading portion 147, and can fix the connection between the electrode assembly 110 and the first current collector 144. As a result, the connection between the electrode assembly 110 and the first current collector 144 restricts the movement of the battery 140 in the height direction, thereby improving the assembly stability of the battery 140.

[0467] The insulator 146 may consist of an insulating polymer resin. For example, the insulator 146 may consist of polyethylene, polypropylene, polyimide, or polybutylene terephthalate.

[0468] The battery housing 142 may further include a vent portion 152 formed on its lower surface. The vent portion 152 corresponds to an area on the lower surface of the battery housing 142 that is thinner than the surrounding area. The vent portion 152 is structurally weaker than the surrounding area. Therefore, if an abnormality occurs in the cylindrical battery 190 and the internal pressure increases above a certain level, the vent portion 152 may rupture, and the gas generated inside the battery housing 142 may be discharged to the outside. The internal pressure at which the vent portion 152 ruptures is approximately 15 kgf / cm². 2 ~35 kgf / cm² 2 It is possible.

[0469] The vent portion 152 may be formed continuously or discontinuously in a circular pattern on the lower surface of the battery housing 142. In a modified form, the vent portion 152 may be formed in a linear pattern or other patterns.

[0470] Figure 18 is a cross-sectional view of a cylindrical battery 200 according to another embodiment of the present invention, obtained by cutting along the Y-axis direction so as to pass through the bent surface region (F in Figure 7g) of the segment included in the segment alignment section (66 in Figure 7g).

[0471] Referring to Figure 18, the cylindrical battery 200 has substantially the same electrode assembly structure as the cylindrical battery 190 shown in Figure 17, and differs in that other structures besides the electrode assembly have been modified.

[0472] Specifically, the cylindrical battery 200 includes a battery housing 171 through which rivet terminals 172 are driven. The rivet terminals 172 are installed through through holes formed in the closed surface (top surface in the drawing) of the battery housing 171. The rivet terminals 172 are reveting into the through holes of the battery housing 171 with a second gasket 173 made of an insulating material interposed between them. The rivet terminals 172 are exposed outward in the direction opposite to the direction of gravity.

[0473] 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 in the center of the closed surface of the battery housing 171. The maximum diameter of the terminal exposure portion 172a may be formed to be larger than the maximum diameter of the through hole formed in the battery housing 171. The terminal insertion portion 172b may penetrate approximately in the center of the closed surface of the battery housing 171 and be electrically connected to the plain portion 146a of the first electrode. The bottom edge of the terminal insertion portion 172b may be riveted onto the inner surface of the battery housing 171. That is, the bottom edge of the terminal insertion portion 172b may have a curved shape toward the inner surface of the battery housing 171. Inside the bottom edge of the terminal insertion portion 172b is a flat portion 172c. The maximum diameter of the bottom of the riveted terminal insertion portion 172b may be even larger than the maximum diameter of the through-hole in the battery housing 171.

[0474] The flat portion 172c of the terminal insertion portion 172b can be welded to the central portion of the first current collector 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 can be used as alternatives.

[0475] An insulator 174 made of an insulating material may be interposed between the first current collector 144 and the inner surface of the battery housing 171. The insulator 174 covers the upper part of the first current collector 144 and the upper peripheral 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 opposite polarity, and causing a short circuit.

[0476] The thickness of the insulator 174 corresponds to or is slightly greater than the distance between the upper surface of the first current collector 144 and the inner surface of the closing portion of the battery housing 171. Therefore, the insulator 174 can come into contact with the upper surface of the first current collector 144 and the inner surface of the closing portion of the battery housing 171.

[0477] The terminal insertion portion 172b of the rivet terminal 172 can be welded to the first current collector 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 rivet portion at the bottom of the terminal insertion portion 172b. Preferably, the through hole may expose the bottom of the terminal insertion portion 172b and the second gasket 173.

[0478] The second gasket 173 is interposed between the battery housing 171 and the rivet terminal 172, preventing 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 the second electrode terminal (e.g., the negative electrode) of the cylindrical battery 200.

[0479] The second gasket 173 includes a gasket exposed portion 173a and a gasket inserted portion 173b. The gasket exposed portion 173a is interposed between the terminal exposed portion 172a of the rivet terminal 172 and the battery housing 171. The gasket inserted portion 173b is interposed between the terminal inserted portion 172b of the rivet terminal 172 and the battery housing 171. The gasket inserted portion 173b can be deformed together with the terminal inserted portion 172b during reveting to make it tightly adhere to the inner surface of the battery housing 171. The second gasket 173 may be made of, for example, an insulating polymer resin.

[0480] The gasket exposed portion 173a of the second gasket 173 may have a form that extends to cover the outer circumferential surface of the terminal exposed portion 172a of the rivet terminal 172. When the second gasket 173 covers the outer circumferential surface of the rivet terminal 172, it is possible to prevent short circuits from occurring during the process of connecting electrical connection components such as busbars to the upper surface of the battery housing 171 and / or the rivet terminal 172. Although not shown, the gasket exposed portion 173a may have a form that extends to cover not only the outer circumferential surface of the terminal exposed portion 172a but also a part of the upper surface.

[0481] When the second gasket 173 is made of a polymer resin, the second gasket 173 can be bonded to the battery housing 171 and the rivet terminal 172 by heat fusion. In this case, the airtightness at the bonding interface between the second gasket 173 and the rivet terminal 172 and the bonding interface between the second gasket 173 and the battery housing 171 is enhanced. On the other hand, when the gasket exposed portion 173a of the second gasket 173 extends to the upper surface of the terminal exposed portion 172a, the rivet terminal 172 may be integrally bonded to the second gasket 173 by insert injection molding.

[0482] On the upper surface of the battery housing 171, the area 175 other than the area occupied by the rivet terminal 172 and the second gasket 173 corresponds to the second electrode terminal having the opposite polarity to the rivet terminal 172.

[0483] The second current collector 176 is coupled to the lower part of the electrode assembly 141. The second current collector 176 is made of a conductive metallic material such as aluminum, steel, copper, or nickel, and is electrically connected to the bent surface region F of the second electrode.

[0484] Preferably, the second current collector 176 is electrically connected to the battery housing 171. Therefore, the second current collector 176 can be fixed by interposing at least a portion of its peripheral edge between the inner surface of the battery housing 171 and the first gasket 178b. As an example, at least a portion of the peripheral edge of the second current collector 176 can be fixed to the beading portion 180 formed at the lower end of the battery housing 171 by welding, while being supported by the lower end surface of the beading portion 180. In a modified example, at least a portion of the peripheral edge of the second current collector 176 can be directly welded to the inner wall surface of the battery housing 171.

[0485] Preferably, the second current collector 176 and the bent surface region F of the second electrode can be joined, for example, by laser welding. The welded portion between the second current collector 176 and the bent surface region F can be separated by a predetermined distance toward the core C with respect to the inner circumferential surface of the beading portion 180.

[0486] The seal 178 that seals the open lower 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 fixes the periphery of the cap plate 178a and the first gasket 178b together. The cap plate 178a is provided with a vent portion 179. The configuration of the vent portion 179 is substantially the same as that of the above-described embodiment (modified form). The lower surface of the cap plate 178a may be located above the lower end of the crimping portion 181. In this case, a space is formed below the cap plate 178a, allowing for smooth ventilation. This is particularly useful when the cylindrical battery 200 is installed so that the crimping portion 181 faces in the direction of gravity.

[0487] 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 seal 178 mainly serves to seal the open lower end of the battery housing 171 and to release gas when the internal pressure of the battery 200 increases above a critical value. The critical value of the internal pressure is 15 kgf / cm². 2 ~35 kgf / cm² 2 That is the case.

[0488] Preferably, the rivet terminal 172 electrically connected to the bent surface region F of the first electrode is used as the first electrode terminal. In addition, the portion 175 of the upper surface of the battery housing 171, excluding the rivet terminal 172, which is electrically connected to the bent surface region F of the second electrode through the second current collector 176, is used as the second electrode terminal with opposite polarity to the first electrode terminal. In this way, when the two electrode terminals are located on the top of the cylindrical battery 200, it is possible to place electrical connection components such as busbars on only one side of the cylindrical battery 200. This can lead to a simplification of the battery pack structure and an improvement in energy density. Furthermore, since the portion 175 used as the second electrode terminal has a substantially flattened shape, it is possible to secure a sufficient contact area for joining electrical connection components such as busbars. As a result, the cylindrical battery 200 can reduce the resistance at the joint of the electrical connection components to a desirable level.

[0489] Figure 19 is a cross-sectional view of a cylindrical battery 210 according to yet another embodiment of the present invention, obtained by cutting along the Y-axis direction so as to pass through the folded surface region (F in Figure 7g) of the segment included in the segment alignment section (66 in Figure 7g).

[0490] Referring to Figure 19, the cylindrical battery 210 includes the electrode assembly 100 shown in Figure 13, and the other components, excluding the electrode assembly 100, are substantially the same as those of the cylindrical battery 190 shown in Figure 17. Therefore, the configurations described with reference to Figures 13 and 17 can be applied substantially similarly to this embodiment.

[0491] Preferably, the first blank portion 146a and the second blank portion 146b of the electrode assembly 100 include a plurality of segment groups 61g. The plurality of segment groups 61g form segment alignment portions (66 in Figure 7f) at the top and bottom of the electrode assembly 100. The segment segments 61 included in the segment alignment portion 66 are bent radially from the electrode assembly 100, for example, from the outer circumference to the core. At this time, the blank portions of the first part B1 and the second part B3 of the first blank portion 146a are shorter in height than the other parts and do not contain segment segments, and are therefore not substantially bent. The same applies to the second blank portion 146b.

[0492] In this embodiment as well, the folded surface region F formed by the segmented segments 61 included in the segmented segment alignment section 66 may include, in order from the core side to the outer circumference, a segmented segment omitted section a1, a segmented segment with variable height a2, and a segmented segment with uniform height a3. However, since the plain portion of the second section B3 is not folded, the radial length of the folded surface region F may be shorter than in the embodiment described above.

[0493] As shown in Figures 11a, 11b, and 11c, the bent surface region F includes a section a1 where the section is omitted, and adjacent to it, a section b1 with a uniform number of layers where the number of layers of section is 10 or more.

[0494] The bent surface region F may also include a layer count reduction section b2 adjacent to the winding turn of the second portion B3 of the electrode assembly 100, where the number of layer counts decreases toward the outer circumference. Preferably, the uniform layer count section b1 may be set as a welding target region.

[0495] In the folded surface region F, the preferred numerical ranges for the ratio of the variable height section a2 of the segment (a2 / c), the ratio of the uniform number of layered segments b1 (b1 / c), and the ratio of the area of ​​the uniform number of layered segments b1 to the area of ​​the folded surface region F have been described above, so a repeated explanation will be omitted.

[0496] The first current collector 144 can be welded to the bent surface region F of the first plain section 146a, and the second current collector 145 can be welded to the bent surface region F of the second plain section 146b.

[0497] The overlapping relationship between the uniform layer number section b1 and the decreasing layer number section b2 and the welding area W, the outer diameters of the first current collector 144 and the second current collector 145, and the configuration in which the first part B1 does not block the core are essentially as described above.

[0498] On the other hand, the second part B3 does not include a segment, and the height of the plain section is lower than that of the segment of the third part B2. Therefore, when the segment of the third part B2 is folded, the second part B3 is not substantially folded. In addition, since the winding turns of the second part B3 are sufficiently separated from the beading section 147, the problem of the winding turns of the second part B3 being damaged during the process of the beading section 147 being pressed in can be solved.

[0499] Figure 20 is a cross-sectional view of a cylindrical battery 220 according to yet another embodiment of the present invention, obtained by cutting along the Y-axis direction so as to pass through the bent surface region (F in Figure 7g) of the segment included in the segment alignment section (66 in Figure 7g).

[0500] Referring to Figure 20, the cylindrical battery 220 includes the electrode assembly 100 shown in Figure 13, and the other components, excluding the electrode assembly 100, are substantially the same as those of the cylindrical battery 200 shown in Figure 18. Therefore, the configurations described with reference to Figures 13 and 18 can be applied substantially similarly to this embodiment.

[0501] Preferably, the first blank portion 146a and the second blank portion 146b of the electrode assembly 100 include a plurality of segment groups 61g, and the plurality of segment groups 61g are arranged radially to form a segment alignment portion (66 in Figure 7f). The segment segments included in the segment alignment portion 66 are bent from the outer circumference side of the electrode assembly 100 toward the core side to form a bent surface region F. At this time, the first portion B1 and the second portion B3 of the first blank portion 146a are not substantially bent toward the core side because their blank portion height is lower than the other portions and they do not contain segment segments. The same applies to the second blank portion 146b.

[0502] Therefore, in this embodiment as well, similar to the embodiment in Figure 19, the folded surface region F may include, in order from the core side to the outer periphery, a section with omitted segment a1, a section with variable segment height a2, and a section with uniform segment height a3. However, since the plain portion of the second part B3 is not folded, the radial length of the folded surface region F may be shorter than in the embodiment described above.

[0503] As shown in Figures 11a, 11b, and 11c, the bent surface region F includes a section a1 where the section is omitted, and adjacent to it, a section b1 with a uniform number of layers where the number of layers of section is 10 or more.

[0504] The bent surface region F may also include a layer count reduction section b2 adjacent to the winding turn of the second portion B3 of the electrode assembly 100, where the number of layer counts decreases toward the outer circumference. Preferably, the uniform layer count section b1 may be set as a welding target region.

[0505] In the folded surface region F, the preferred numerical ranges for the ratio of the variable height section a2 of the segment (a2 / c), the ratio of the uniform number of layered segments b1 (b1 / c), and the ratio of the area of ​​the uniform number of layered segments b1 to the area of ​​the folded surface region F have been described above, so a repeated explanation will be omitted.

[0506] The first current collector 144 can be welded to the bent surface region F of the first plain section 146a, and the second current collector 176 can be welded to the bent surface region F of the second plain section 146b.

[0507] The overlapping relationship between the uniform layer count section b1 and the decreasing layer count section b2 and the welding area W, the outer diameters of the first current collector 144 and the second current collector 176, and the configuration in which the first part B1 does not block the core are essentially as described above.

[0508] In the above-described embodiment (modified form), the first current collector 144 and the second current collector 176 included in the cylindrical batteries 200 and 220, which include the rivet terminal 172, may have an improved structure as shown in Figures 21 and 22.

[0509] The improved structure of the first current collector 144 and the second current collector 176 can contribute to improving vibration resistance and energy density while reducing the resistance of the cylindrical battery. In particular, the first current collector 144 and the second current collector 176 are effective when applied to large cylindrical batteries with a height-to-diameter ratio greater than 0.4.

[0510] Figure 21 is a top view showing the structure of the first current collector 144 according to one embodiment of the present invention.

[0511] Referring to Figures 20 and 21, the first current collector 144 may include a peripheral portion 144a, a first blank portion connecting portion 144b, and a terminal connecting portion 144c. The peripheral portion 144a is positioned on the upper part of the electrode assembly 100. The peripheral portion 144a has an empty space S inside it. open It may have a substantially rim shape in which the peripheral edge portion 144a is formed. The drawings only show the case where the peripheral edge portion 144a is substantially circular in shape, but this does not limit the present invention. The peripheral edge portion 144a may be substantially square, hexagonal, octagonal, or any other rim shape, contrary to the figures shown. The number of peripheral edges 144a may be increased to two or more. In this case, another peripheral edge portion of the rim shape may be included inside the peripheral edge portion 144a.

[0512] The terminal coupling portion 144c may have a diameter that is the same as or larger than the diameter of the flat portion 172c formed on the bottom surface of the rivet terminal 172, in order to secure a welding area for coupling with the flat portion 172c formed on the bottom surface of the rivet terminal 172.

[0513] The first plain portion joining portion 144b extends inward from the peripheral portion 144a and is joined to the bent surface region F of the plain portion 146a by welding. The terminal joining portion 144c is located inside the peripheral portion 144a, separated from the first plain portion joining portion 144b. The terminal joining portion 144c can be joined to the rivet terminal 172 by welding. The terminal joining portion 144c is located in an inner space S surrounded, for example, by the peripheral portion 144a. open It may be located approximately in the center. 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 is not exposed to the outside of the terminal coupling portion 144c. Therefore, the terminal coupling portion 144c may have a larger diameter or width than the hole formed in the core C of the electrode assembly 100.

[0514] The first plain section coupling portion 144b and the terminal coupling portion 144c are not directly connected but are arranged separately and can be indirectly connected by the peripheral portion 144a. In this way, the first current collector 144 has a structure in which the first plain section coupling portion 144b and the terminal coupling portion 144c are not directly connected but are connected through the peripheral portion 144a, so that when shock and / or vibration occurs in the cylindrical battery 220, the shock applied to the coupling portion between the first plain section coupling portion 144b and the first plain section 146a and the coupling portion between the terminal coupling portion 144c and the rivet terminal 172 can be dispersed. Four first plain section coupling portions 144b are shown in the drawing, but this does not limit the present invention. The number of the first plain section coupling portions 144b is determined by 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 Various factors can be taken into consideration when making a decision.

[0515] The first current collector 144 may further include a bridge portion 144d that extends inward from the peripheral portion 144a and is connected to the terminal coupling portion 144c. The bridge portion 144d may be formed with a cross-sectional area smaller than that of the first plain portion coupling portion 144b and the peripheral portion 144a, at least in part. For example, the bridge portion 144d may be formed with a width and / or thickness that is even smaller than that of the first plain portion coupling portion 144b, at least in part. In this case, the electrical resistance of the bridge portion 144d increases. As a result, when current flows through the bridge portion 144d, the relatively large resistance causes melting due to overcurrent heating in part of the bridge portion 144d, which irreversibly interrupts the overcurrent. The cross-sectional area of ​​the bridge portion 144d may be adjusted to an appropriate level to take such overcurrent interruption function into consideration.

[0516] 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. When the tapered portion 144e is provided, the rigidity of the component is improved at the connection point between the bridge portion 144d and the peripheral portion 144a. When the tapered portion 144e is provided, in the manufacturing process of the cylindrical battery 220, for example, a transfer device and / or an operator can easily and safely transfer the first current collector 144 and / or the assembly of the first current collector 144 and the electrode assembly 100 by gripping the tapered portion 144e. In other words, when the tapered portion 144e is provided, product defects that occur when gripping parts that are welded to other parts, such as the first plain portion coupling portion 144b and the terminal coupling portion 144c, can be prevented.

[0517] Multiple first plain portion joining portions 144b may be provided. Multiple first plain portion joining portions 144b may be arranged at equal intervals from one another along the extension direction of the peripheral portion 144a. The extended lengths of each of the multiple first plain portion joining portions 144b may be substantially the same. The first plain portion joining portions 144b may be joined to the bent surface region F of the plain portion 146a by laser welding. Welding may be replaced by ultrasonic welding, spot welding, or the like.

[0518] The weld pattern 144f formed by welding the first plain joint portion 144b and the bent surface region F may have a structure that extends along the radial direction of the electrode assembly 100. The weld pattern 144f may be an arrangement of line patterns or dot patterns.

[0519] The welding pattern 144f corresponds to the welding area. Therefore, it is preferable that the welding pattern 144f overlaps with the uniform layer number section b1 of the bent surface area F by 50% or more. The welding pattern 144f that does not overlap with the uniform layer number section b1 may overlap with the decreasing layer number section b2. More preferably, the entire welding pattern 144f may overlap with the uniform layer number section b1 of the bent surface area F. It is preferable that the uniform layer number section b1 and the selectively decreasing layer number section b2 of the bent surface area F below the point where the welding pattern 144f is formed have 10 or more layers per segment.

[0520] The terminal coupling portion 144c may be arranged so as to be surrounded by a plurality of the first plain portion coupling portions 144b. The terminal coupling portion 144c may be joined 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 plain portion coupling portions 144b. In this case, the distance from the bridge portion 144d to one of the pair of first plain portion coupling portions 144b along the extension direction of the peripheral portion 144a may be substantially the same as the distance from the bridge portion 144d to the other of the pair of first plain portion coupling portions 144b along the extension direction of the peripheral portion 144a. The cross-sectional area of ​​each of the plurality of first plain portion coupling portions 144b may be formed to be substantially the same. The width and thickness of each of the plurality of first plain portion coupling portions 144b may be formed to be substantially the same.

[0521] Although not shown in the figures, there may be multiple bridge portions 144d. Each of the multiple bridge portions 144d may be positioned between adjacent pairs of first plain portion connecting portions 144b. The multiple bridge portions 144d may be positioned at approximately equal intervals from one another along the extension direction of the peripheral portion 144a. The distance from each of the multiple bridge portions 144d to one of adjacent pairs of first plain portion connecting portions 144b along the extension direction of the peripheral portion 144a may be approximately the same as the distance to the other first plain portion connecting portion 144b.

[0522] As described above, when multiple first blank section connecting portions 144b and / or bridge portions 144d are provided, if the distance between the first blank section connecting portions 144b and / or the distance between the bridge portions 144d and / or the distance between the first blank section connecting portions 144b and bridge portions 144d is kept constant, then a smooth flow of current from the first blank section connecting portions 144b to the bridge portions 144d or from the bridge portions 144d to the first blank section connecting portions 144b will be formed.

[0523] The bridge portion 144d may include a notching portion N formed to partially reduce the cross-sectional area of ​​the bridge portion 144d. Adjustment of the cross-sectional area of ​​the notching portion N can be achieved, for example, by partially reducing the width and / or thickness of the bridge portion 144d. When the notching portion N is provided, the electrical resistance in the region in which the notching portion N is formed increases, thereby enabling rapid current interruption in the event of an overcurrent.

[0524] The notch N is preferably provided in a region corresponding to the uniform layering section of the electrode assembly 100 in order to prevent foreign matter generated during fracture from flowing into the inside of the electrode assembly 100. This is because in this region the number of layers of the segment of the plain section 146a is maintained at its maximum, and the overlapping segment can function as a mask.

[0525] The notch N may be covered and wrapped with insulating tape. In this case, the heat generated in the notch N will not be dissipated to the outside, and when an overcurrent flows through the bridge portion 144d, the notch N will break more quickly.

[0526] Figure 22 is a top view showing the structure of the second current collector 176 according to one embodiment of the present invention.

[0527] Referring to Figures 20 and 22, the second current collector 176 is positioned at the bottom of the electrode assembly 100. The second current collector 176 may also be configured to electrically connect the plain portion 146b of the electrode assembly 100 to the battery housing 171. The second current collector 176 is made of a conductive metallic material and is electrically connected to the bent surface region F of the plain portion 146b. The second current collector 176 is also electrically connected to the battery housing 171. The peripheral portion of the second current collector 176 may be interposed and fixed between the inner surface of the battery housing 171 and the first gasket 178b. Specifically, the peripheral portion of the second current collector 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 alternatively, the peripheral portion of the second current collector 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.

[0528] The second current collector 176 may include a support portion 176a positioned at the bottom of the electrode assembly 100, a second plain portion connecting portion 176b extending from the support portion 176a along the radial direction of the electrode assembly 100 and coupled to the bent surface region F of the plain portion 146b, and a housing connecting portion 176c extending from the support portion 176a inclined toward the inner surface of the battery housing 171 with respect to the radial direction of the electrode assembly 100 and coupled to the inner surface. The second plain portion connecting portion 176b and the housing connecting portion 176c are indirectly connected through the support portion 176a and are not directly connected to each other. Therefore, when an external impact is applied to the cylindrical battery 220 according to one embodiment of the present invention, damage to the coupling portion between the second current collector 176 and the electrode assembly 100 and the coupling portion between the second current collector 176 and the battery housing 171 can be minimized. However, the second current collector 176 according to one embodiment of the present invention is not limited to having a structure in which the second blank portion coupling portion 176b and the housing coupling portion 176c are indirectly connected. For example, the second current collector 176 may have a structure in which there is no support portion 176a that indirectly connects the second blank portion coupling portion 176b and the housing coupling portion 176c, and / or a structure in which the blank portion 146b and the housing coupling portion 176c are directly connected.

[0529] The support portion 176a and the second plain portion connecting portion 176b are positioned at the bottom of the electrode assembly 100. The second plain portion connecting portion 176b is connected to the bent surface region F of the plain portion 146b. Not only the second plain portion connecting portion 176b, but the support portion 176a can also be connected to the plain portion 146b. The second plain portion connecting portion 176b and the bent surface region F of the plain portion 146b can be connected by laser welding. Welding can be replaced by ultrasonic welding, spot welding, etc. The support portion 176a and the second plain portion connecting portion 176b are positioned above the beading portion 180 if a beading portion 180 is formed on the battery housing 171.

[0530] The support portion 176a includes a current collector 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 collector hole 176d, which are in communication with each other, can function as a passage for inserting a welding rod for welding between the rivet terminal 172 and the terminal coupling portion 144c of the first current collector 144, or for irradiating with a laser beam.

[0531] The current collector hole 176d is a hole formed in the core C of the electrode assembly 100 with radius r c 0.5r c It may have a radius greater than or equal to the above. The radius of the current collector hole 176d is 0.5r c ~1.0r c In this case, when venting occurs in the cylindrical battery 220, the venting pressure prevents the separation membrane and electrode winding structure near the core C of the electrode assembly 100 from being pushed out of the core C. The radius of the current collector hole 176d is 1.0r c A larger value allows core C to open to its maximum extent, facilitating the injection of electrolytes during the electrolyte injection process.

[0532] When multiple second blank portion connecting portions 176b are provided, the multiple second blank portion connecting portions 176b may have a configuration in which they extend substantially radially from the support portion 176a of the second current collector 176 toward the side wall of the battery housing 171. Each of the multiple second blank portion connecting portions 176b may be located spaced apart from each other along the perimeter of the support portion 176a.

[0533] Multiple housing coupling portions 176c may be provided. In this case, the multiple housing coupling portions 176c may have a configuration that extends substantially radially from the center of the second current collector 176 toward the side wall of the battery housing 171. This allows for electrical connection between the second current collector 176 and the battery housing 171 at multiple points. By performing coupling for electrical connection at multiple points in this way, the coupling area can be maximized and electrical resistance can be minimized. Each of the multiple housing coupling portions 176c may be located spaced apart from each other along the perimeter of the support portion 176a. At least one housing coupling portion 176c may be located between adjacent second plain portion coupling portions 176b. The multiple 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 portions 176c may be coupled to the lower surface of the beading portion 180 in particular by laser welding. Welding can be replaced by ultrasonic welding, spot welding, etc. By welding multiple housing coupling portions 176c onto the beading portion 180 in this manner, the current path can be distributed radially, limiting the resistance level of the cylindrical battery 220 to approximately 4 mΩ or less. Furthermore, by shaping the lower surface of the beading portion 180 to extend in a direction substantially parallel to the upper surface of the battery housing 171, that is, in a direction substantially perpendicular to the side wall of the battery housing 171, and shaping the housing coupling portions 176c to extend in the same direction, that is, 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 portion of the beading portion 180 in this manner, welding between the two parts is performed smoothly, thereby improving the bonding force between the two parts and minimizing the increase in resistance at the joint.

[0534] The housing coupling portion 176c may include a contact portion 176e that is coupled to the inner surface of the battery housing 171, and a coupling portion 176f that connects the support portion 176a and the contact portion 176e.

[0535] The contact portion 176e is coupled to the inner surface of the battery housing 171. If a beading portion 180 is formed on 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 on 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 have a form that extends for a predetermined length along the circumferential direction of the battery housing 171 on the beading portion 180.

[0536] The connecting portion 176f can be bent at an obtuse angle. The bending point may be above 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 is divided into a lower and upper part with respect to the bending point, and the length of the lower part may be greater than that of the upper part. Also, the inclination angle with respect to the surface of the support portion 176a may be even greater at the lower part of the bending point than at the upper part. When the connecting portion 176f is bent, it can buffer the 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 connecting portion 176f is deformed as the bending point of the connecting portion 176f moves upward, thereby buffering stress.

[0537] On the other hand, it is preferable that the maximum distance from the center of the second current collector 176 to the end of the second plain section connecting portion 176b along the radial direction of the electrode assembly 100 is the same as 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 plain section connecting portion 176b from pressing against the periphery of the electrode assembly 100 during the sizing process in which the battery housing 171 is compressed along the height direction.

[0538] The second plain joint 176b includes a hole 176g. The hole 176g can be used as a passage for the electrolyte to move. The weld pattern 176h formed by welding the second plain joint 176b to the bent surface region F may have a structure that extends along the radial direction of the electrode assembly 100. The weld pattern 176h may be an arrangement of line patterns or dot patterns.

[0539] The welding pattern 176h corresponds to the welding area. Therefore, it is preferable that the welding pattern 176h overlaps by 50% or more with the uniform layer number section b1 of the bent surface region F located at the bottom of the electrode assembly 100. The welding pattern 176h that does not overlap with the uniform layer number section b1 may overlap with the decreasing layer number section b2. More preferably, the entire welding pattern 176h may overlap with the uniform layer number section b1 of the bent surface region F. It is preferable that the uniform layer number section b1 and the selectively decreasing layer number section b2 of the bent surface region F located above the point where the welding pattern 176h is formed have 10 or more layers of segmented material.

[0540] The first current collector 144 and the second current collector 176 described above have different outer diameters. The outer diameter is the outer diameter of the contact area between the bent surface area F and the current collector. The outer diameter is defined as the maximum value of the distance between two points where a straight line passing through the center of the electrode assembly core C intersects with the edge of the contact area. Since the second current collector 176 is located inside the beading area, its outer diameter is smaller than that of the first current collector 144. Also, the length of the welding pattern 144f of the first current collector 144 is even longer than the length of the welding pattern 176h of the second current collector 176. Preferably, the welding patterns 144f and 176h may extend outward from substantially the same point with respect to the center of the core C.

[0541] The cylindrical batteries 200 and 220 according to embodiments of the present invention can be electrically connected at the top.

[0542] Figure 23 is a top view showing multiple cylindrical batteries 200 electrically connected, and Figure 24 is a partial enlargement of Figure 23. The cylindrical batteries 200 can be replaced with cylindrical batteries 220 of other structures.

[0543] Referring to Figures 23 and 24, multiple cylindrical batteries 200 can be connected in series and parallel at the top of the cylindrical batteries 200 using busbars 210. The number of cylindrical batteries 200 can be increased or decreased depending on the capacity of the battery pack.

[0544] In each cylindrical battery 200, the rivet terminal 172 has positive polarity, and the flattened surface 171a around the rivet terminal 172 of the battery housing 171 may have negative polarity. Of course, the opposite is also possible.

[0545] Preferably, multiple cylindrical batteries 200 may be arranged in multiple columns and rows. In the drawing, columns are in the vertical direction and rows are in the horizontal direction. Also, in order to maximize space efficiency, the cylindrical batteries 200 may be arranged in a closest packing structure. A 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. Preferably, the busbar 210 connects cylindrical batteries 200 arranged in the same column in parallel and connects cylindrical batteries 200 arranged in two adjacent columns in series.

[0546] Preferably, the busbar 210 may include a body portion 211, a plurality of first busbar terminals 212, and a plurality of second busbar terminals 213 for series and parallel connections.

[0547] 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 be regularly bent in a zigzag pattern.

[0548] Multiple first busbar terminals 212 extend from one side of the body portion 211 and can be electrically coupled to rivet terminals 172 of a cylindrical battery 200 located on the same side. The electrical coupling between the first busbar terminals 212 and the rivet terminals 172 can be performed by laser welding, ultrasonic welding, or the like.

[0549] Multiple second busbar terminals 213 can extend from the other side of the body portion 211 and be electrically coupled to the flattened surface 171a around the rivet terminal 172 located on the other side. The electrical coupling between the second busbar terminals 213 and the flattened surface 171a can be performed by laser welding, ultrasonic welding, or the like.

[0550] Preferably, the body portion 211, the plurality of first busbar terminals 212, and the plurality of second busbar terminals 213 may be made of 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. As a modified example, the body portion 211, the plurality of first busbar terminals 212, and the second busbar terminals 213 may be manufactured as separate pieces and then joined together by welding or the like.

[0551] The cylindrical battery 200 according to the embodiment described above has a structure in which resistance is minimized by increasing the welding area through the bent surface region F, doubling the current path using the second current collector 176, and minimizing the current path length. The AC resistance of the cylindrical battery 200, measured by a resistance meter between the positive electrode and the negative electrode, i.e., between the rivet terminal 172 and the surrounding flattened surface 171a, can be about 4 mΩ or less, which is suitable for rapid charging.

[0552] In one embodiment of the present invention, the cylindrical battery 200 has a rivet terminal 172 with positive polarity and a flattened surface 171a with negative polarity located in the same direction, so that electrical connections between cylindrical batteries 200 can be easily achieved using a busbar 210.

[0553] Furthermore, because the rivet terminals 172 of the cylindrical battery 200 and the surrounding flat surfaces 171a have a large surface area, sufficient bonding area for the busbar 210 can be secured, thereby significantly reducing the resistance of the battery pack including the cylindrical battery 200.

[0554] Furthermore, 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.

[0555] The cylindrical battery according to the above-described embodiment (modified form) is used in the manufacture of a battery pack.

[0556] Figure 25 is a schematic diagram showing the configuration of a battery pack according to one embodiment of the present invention.

[0557] Referring to Figure 25, a battery pack 300 according to one embodiment of the present invention includes an assembly of electrically connected cylindrical batteries 301 and a pack housing 302 that houses them. The cylindrical batteries 301 may be any one of the batteries according to the embodiments (modified forms) described above. For illustrative purposes, components such as busbars, cooling units, and external terminals for the electrical connection of the cylindrical batteries 301 are not shown.

[0558] The battery pack 300 is installed in a vehicle. The vehicle may, for example, be an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle includes four-wheeled vehicles and two-wheeled vehicles.

[0559] Figure 26 is a diagram illustrating an automobile including the battery pack 300 shown in Figure 25.

[0560] Referring to Figure 26, an automobile V according to one embodiment of the present invention includes a battery pack 300 according to one embodiment of the present invention. The automobile V operates by receiving power from the battery pack 300 according to one embodiment of the present invention.

[0561] According to one embodiment of the present invention, the internal resistance of the battery can be reduced and the energy density increased by using the plain portions protruding from the upper and lower sides of the electrode assembly as electrode tabs.

[0562] Furthermore, according to one embodiment of the present invention, by improving the structure of the plain portion of the electrode assembly, interference between the electrode assembly and the inner circumferential surface of the battery housing is prevented during the process of forming the beading portion of the battery housing, thereby preventing internal short circuits in the cylindrical battery due to partial deformation of the electrode assembly.

[0563] Furthermore, according to one embodiment of the present invention, by improving the structure of the plain portion of the electrode assembly, it is possible to prevent the plain portion from tearing when bent, and to sufficiently increase the number of overlapping layers of the plain portion to improve the welding strength of the current collector.

[0564] Furthermore, according to one embodiment of the present invention, by forming multiple sub-sections on the plain portion of the electrode, arranging the multiple sub-sections in a predetermined direction when winding the electrode, and exposing the edges of the active material layer formed on the electrode from between the winding turns of the separation membrane in areas where sub-sections are not arranged, the electrolyte impregnation (speed and uniformity) can be increased.

[0565] Furthermore, according to one embodiment of the present invention, by designing the minimum conditions for the inscribed angle of the segment alignment section, taking into account the electrode thickness tolerance and, optionally, the width of the weld line, the welding process of the current collector can be easily performed even if the segment group included in the segment alignment section rotates clockwise or counterclockwise.

[0566] Furthermore, according to one embodiment of the present invention, by applying a segmentation structure to the plain portion of the electrode and optimizing the dimensions of the segmentation segments (width, height, and spacing pitch), the number of stacked segmentation segments in the area used as a welding target area can be sufficiently increased, thereby improving the physical properties of the area where the current collector is welded.

[0567] Furthermore, according to one embodiment of the present invention, by applying a structure in which a current collector is welded over a wide area to a bent surface region formed by bending a segment, it is possible to provide an electrode assembly with improved energy density and reduced resistance.

[0568] Furthermore, according to one embodiment of the present invention, a cylindrical battery with an improved design for electrical wiring at the top can be provided.

[0569] Furthermore, according to one embodiment of the present invention, by improving the structure of the plain portion adjacent to the core of the electrode assembly, it is possible to prevent the cavity in the core of the electrode assembly from becoming blocked when the plain portion is bent, thereby facilitating the electrolyte injection process and the welding process between the battery housing (or rivet terminal) and the current collector.

[0570] Furthermore, according to one embodiment of the present invention, it is possible to provide a cylindrical battery having a structure with low internal resistance, prevention of internal short circuits, and improved welding strength between the current collector and the plain portion, a battery pack including the cylindrical battery, and an automobile.

[0571] 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 cylindrical battery, and an automobile.

[0572] As described above, the present invention has been explained with limited embodiments and drawings, but it goes without saying that the present invention is not limited thereto, and that various modifications and variations are possible within the equivalent scope of the technical concept and claims of the present invention by persons with ordinary skill in the art to which the present invention belongs. [Explanation of Symbols]

[0573] 10 positive electrode 11 Plain section 12 Separation membrane 20 Current collector 21 Active material 22 Plain section 30 Current collector 31 Current collector 32 Plain section 33 Cavity 41 Current collector 42 Active material layer 43 Plain section 44 Insulating coating layer 53 Side 55 Electrolyte-impregnated area 60 electrodes 61-minute section 63 Bottom 63 Cutting groove 63 side 63 Round Section 64-minute segment omitted 66-minute section alignment 100 electrode assembly 101 End 102 cores 110 Electrode assembly 111 End 112 cores 120 Electrode assembly 121 End 122 cores 130 Electrode assembly 131 End 132 cores 140 batteries 141 Electrode assembly 142 Battery Housing 143 Sealed body 144 First current collector 145 Second current collector 146 Insulator 146 Plain section 147 Beading section 148 Crimping Section 149 Reed 151 lead holes 152 Vent section 171 Battery Housing 172 Rivet terminals 173 Second Gasket 174 Insulator 176 Second current collector 178 Sealed body 179 Vent section 180 Beading section 181 Crimping section 190 Cylindrical Battery 200 Cylindrical Battery 210 Cylindrical Battery, Busbar 211 Body part 212 First busbar terminal 213 Second busbar terminal 220 Cylindrical Battery 300 Battery Pack 301 Cylindrical Battery 302 Pack Housing

Claims

1. An electrode assembly having a core and outer circumference defined by winding a first electrode, a second electrode, and a separation membrane 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 the winding direction, and a first plain portion that is not coated with an active material layer and is exposed to the outside of the separation film. The first plain section includes a segment section which is divided into a plurality of segment sections that can be independently folded by a plurality of cutting grooves provided along the winding direction, The segment section includes a plurality of segment groups arranged along the winding direction with intervals between groups, each segment group includes one or more segments, and the plurality of segment groups constitute one or more segment alignment sections on one side of the electrode assembly. The segment alignment section includes p segments (where p is a natural number greater than 2) arranged radially, and the central point of the arc of the winding turn in which the p segment segments are located is C, extending radially from the core side. １ ~C ｐ When defined as, the above C １ ~C ｐ An electrode assembly in which at least a portion of the electrodes are not located on a predetermined alignment line extending radially from the center of the core.

2. The aforementioned segment alignment section consists of n segments. The electrode assembly according to claim 1, wherein the n segment alignment portions are spaced apart along the circumferential direction of the electrode assembly.

3. The electrode assembly according to claim 2, wherein n is 2 to 9.

4. n segment groups are arranged in the same winding turn, The electrode assembly according to claim 2, wherein the n segment groups are arranged at substantially equal intervals along the winding direction.

5. Said C １ ~C ｐ More than 50% of the electrode assembly is in a state rotated in the winding direction of the electrode assembly with respect to the alignment line, according to claim 1.

6. Said C １ ~C ｐ More than 50% of the electrode assembly is rotated in the opposite direction to the winding direction of the electrode assembly with respect to the alignment line, according to claim 1.

7. The electrode assembly according to claim 2, wherein the n segment alignment sections are arranged rotationally symmetrically with respect to the center of the core.

8. The electrode assembly according to claim 7, wherein the rotational symmetry angle is 40°, 45°, 60°, 72°, 90°, 120°, or 180°.

9. The electrode assembly according to claim 2, wherein the n segment alignment sections are arranged point-symmetrically with respect to the center of the core.

10. The electrode assembly according to claim 2, wherein the n segment alignment portions extend radially with respect to the center of the core.

11. The electrode assembly according to any one of claims 1 to 10, wherein the segment alignment portion, when viewed from the winding axis direction, has a geometric shape consisting of an inner arc adjacent to the core, an outer arc adjacent to the outer circumference, and two lines connecting the ends of the arcs of the winding turns in which each segment group is located from the core side to the outer circumference side.

12. The electrode assembly according to claim 11, wherein the geometric shape is a fan shape.

13. The electrode assembly according to claim 11, wherein the two lines each extend in a nonlinear manner.

14. The electrode assembly according to claim 1, comprising a bent surface region formed by bending the p subsection groups toward the core side.

15. The present invention further includes a current collector welded to the aforementioned bent surface region, The electrode assembly according to claim 14, wherein, when viewed from the winding axis direction of the electrode assembly, the arc of the winding turn in which the p segment groups are located intersects the weld line of the current collector, and optionally, a virtual line extending from the weld line with the same width.

16. The electrode assembly according to claim 15, wherein the width of the welding line is 1 mm or more.

17. The C of the arc of the winding turn １ to C ｐ When the arc of the winding turn is virtually rotated so that it is located on the alignment line, the arcs of the winding turns are arranged in a fan shape, With respect to the alignment line, the maximum rotation angle θ of the end of the segment group included in the segment alignment section ｍａｘ , the inscribed angle θ of the sector shape ｄｅｓｉｇｎ , and the maximum value of the inscribed angles with respect to half the arc of the winding turn intersecting the weld line is θ ｗｅｌｄ，ｍａｘ When defined as, The following relationship i ｄｅｓｉｇｎ >θ ｍａｘ +θ ｗｅｌｄ，ｍａｘ The electrode assembly according to claim 15, satisfying the requirements.

18. Said θ ｗｅｌｄ，ｍａｘ The following formula i ｗｅｌｄ，ｍａｘ = (360゜×0.5×d) ａｒｃ ) / (222) The value is determined by d ａｒｃ The electrode assembly according to claim 17, wherein is the maximum length of the arc of the winding turn intersecting the weld line, and r is the radius of the arc of the winding turn with respect to the center of the core.

19. When the thickness tolerance of the electrode corresponding to the sum of the thickness tolerances of the first electrode and the second electrode falls within the range of ±1 μm, the θ ｄｅｓｉｇｎ The electrode assembly according to claim 17, wherein the angle is greater than 38°.

20. When the thickness tolerance of the electrode corresponding to the sum of the thickness tolerances of the first electrode and the second electrode falls within the range of ±2 μm, the θ ｄｅｓｉｇｎ The electrode assembly according to claim 17, wherein the angle is greater than 68°.

21. When the thickness tolerance of the electrode corresponding to the sum of the thickness tolerances of the first electrode and the second electrode falls within the range of ±3 μm, the θ ｄｅｓｉｇｎ The electrode assembly according to claim 17, wherein the angle is greater than 100°.

22. When the thickness tolerance of the electrode corresponding to the sum of the thickness tolerances of the first electrode and the second electrode falls within the range of ±4 μm, the θ ｄｅｓｉｇｎ The electrode assembly according to claim 17, wherein the angle is greater than 132°.

23. When the thickness tolerance of the electrode corresponding to the sum of the thickness tolerances of the first electrode and the second electrode falls within the range of ±5 μm, the θ ｄｅｓｉｇｎ The electrode assembly according to claim 17, wherein the angle is greater than 176°.

24. The electrode assembly according to claim 2, wherein, between adjacent segment alignment portions in the circumferential direction, the end portion of the first active material portion in the winding axis direction is exposed from between the ends of radially adjacent separation membranes.

25. The number of electrolyte-impregnated parts is n. The electrode assembly according to claim 24, wherein the electrolyte-impregnated portion extends radially with respect to the center of the core.

26. The material further includes an insulating layer that covers the boundary region between the first plain portion and the active material layer along the winding direction, The electrode assembly according to claim 1, wherein a gap is provided between the insulating layer and the separation membrane.

27. The second electrode includes a second active material portion coated with an active material layer along the winding direction, and a second plain portion that is not coated with an active material layer and is exposed to the outside of the separation film so as to face the first plain portion along the winding axis direction. The second plain section includes a segment section which is divided into a plurality of segments that can be independently folded by a plurality of cutting grooves provided along the winding direction, The segmented section of the second blank portion includes a plurality of segmented section groups arranged along the winding direction with intervals between groups, each segmented section group includes one or more segmented sections, and the plurality of such segmented section groups constitute one or more segmented section alignment sections on one side of the electrode assembly. The segment alignment section of the second blank section includes q segments (where q is a natural number greater than 2) arranged radially, and the center point of the arc of the winding turn in which the q segment groups are located is C, extending radially from the core side. １ ~C ｑ When defined as, the above C １ ~C ｑ The electrode assembly according to claim 1, wherein at least a portion of the electrodes are not located on a predetermined alignment line extending radially from the center of the core.

28. An electrode assembly having a core and outer circumference defined by winding a first electrode, a second electrode, and a separation membrane 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 the winding direction, and a first plain portion that is not coated with an active material layer and is exposed to the outside of the separation film. The first plain section includes a segment section which is divided into a plurality of segment sections that can be independently folded by a plurality of cutting grooves provided along the winding direction, The segment section includes a plurality of segment groups arranged along the winding direction with intervals between groups, each segment group includes one or more segments, and the plurality of segment groups constitute a plurality of segment alignment sections on one side of the electrode assembly. An electrode assembly in which multiple segments are arranged rotationally symmetrically with respect to the center of the core.

29. The electrode assembly according to claim 28, wherein each of the multiple segment alignment sections has an asymmetric structure when viewed from the winding axis direction.

30. The segment alignment section includes p segments (where p is a natural number greater than 2) arranged along the radial direction. The asymmetric structure is such that the central point of the arc of the winding turn in which the p segment groups are located is radially aligned from the core side to C １ ~C ｐ When defined as, the above C １ ~C ｐ The electrode assembly according to claim 29, wherein at least a portion of the structure is not located on a predetermined alignment line extending radially from the center of the core.

31. An electrode assembly in which a core and outer circumference are defined by winding a first electrode, a second electrode, and a separation membrane interposed between the first electrode and the second electrode 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 plain portion that is not coated with an active material layer and is exposed to the outside of the separation membrane, and the first plain portion includes segment sections that are divided into a plurality of segment sections that can be independently bent by a plurality of cutting grooves provided along the winding direction, The segment section includes a plurality of segment groups arranged along the winding direction with a group spacing between them, each segment group includes one or more segment pieces, and the plurality of segment groups constitute one or more segment alignment sections on one side of the electrode assembly, and the segment alignment section includes a bent surface region formed by bending p (p is a natural number greater than 2) segment groups arranged along the radial direction, and the center point of the arc of the winding turn in which the p segment groups are located is C radially from the core side. １ ~C ｐ When defined as, the above C １ ~C ｐ An electrode assembly in which at least a portion of the electrodes are not located on a predetermined alignment line extending radially from the center of the core, A battery housing having an open end and a closed end, housing the electrode assembly through the open end, and electrically connected to one of the first electrode and the second electrode to have a first polarity, A sealing body that seals the open end of the battery housing, A terminal having a second polarity, electrically connected to the other of the first electrode and the second electrode, with its surface exposed to the outside, Includes a battery.

32. The present invention further includes a current collector electrically coupled to the aforementioned bent surface region, The battery according to claim 31, wherein, when viewed from the winding axis direction of the electrode assembly, the arc of the winding turn in which the p segment groups are located intersects the weld line of the current collector, and optionally, a virtual line extending from the weld line.

33. A cavity is provided in the core of the electrode assembly. The battery according to claim 31, wherein the cavity is open to the outside without being blocked by the bent surface region.

34. The sealing body includes a cap plate that seals the open end of the battery housing, and a gasket that wraps around the periphery of the cap plate and is crimped to the open end of the battery housing. The battery according to claim 31, wherein the terminal having the second polarity is the cap plate.

35. The present invention further includes a current collector that is electrically connected to the blank portion of the second electrode having the first polarity, and whose peripheral edge is coupled to the side wall of the battery housing, The sealing body includes a non-polarized cap plate and a gasket that wraps around the periphery of the cap plate and is crimped to the open end of the battery housing. The battery according to claim 31, wherein the battery housing is insulatedly mounted in a through hole formed in the center of the closed end and includes a rivet terminal electrically connected to the first electrode and having the second polarity.

36. An electrode assembly having a core and outer circumference defined by winding a first electrode, a second electrode, and a separation membrane interposed between the first electrode and the second electrode 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 plain portion not coated with an active material layer and exposed to the outside of the separation membrane, the first plain portion includes segment sections divided into a plurality of independently bendable segment sections by a plurality of cutting grooves provided along the winding direction, the segment sections include a plurality of segment group arrangements with inter-group spacing along the winding direction, each segment group includes one or more segment sections, the plurality of segment groups constitute a plurality of segment alignment sections on one side of the electrode assembly, and the plurality of segment alignment sections are arranged rotationally symmetrically with respect to the center of the core, A battery housing having an open end and a closed end, housing the electrode assembly through the open end, and electrically connected to one of the first electrode and the second electrode to have a first polarity, A sealing body that seals the open end of the battery housing, A terminal having a second polarity, electrically connected to the other of the first electrode and the second electrode, with its surface exposed to the outside, A battery that includes this.

37. The battery according to claim 36, wherein each of the plurality of segment alignment sections has an asymmetric structure when viewed from the winding axis direction.

38. The segment alignment section includes p segments (where p is a natural number greater than 2) arranged along the radial direction. The asymmetric structure is such that the central point of the arc of the winding turn in which the p segment groups are located is radially aligned from the core side to C １ ~C ｐ When defined as, the above C １ ~C ｐ The battery according to claim 37, wherein at least a portion of the structure is not located on a predetermined alignment line extending radially from the center of the core.

39. The present invention further includes a current collector electrically coupled to the aforementioned bent surface region, The battery according to claim 36, wherein, when viewed from the winding axis direction of the electrode assembly, the arc of the winding turn in which the p segment groups are located intersects the weld line of the current collector, and optionally, a virtual line extending from the weld line.

40. A cavity is provided in the core of the electrode assembly. The battery according to claim 36, wherein the cavity is open to the outside without being blocked by the bent surface region.

41. The sealing body includes a cap plate that seals the open end of the battery housing, and a gasket that wraps around the periphery of the cap plate and is crimped to the open end of the battery housing. The battery according to claim 36, wherein the terminal having the second polarity is the cap plate.

42. The present invention further includes a current collector that is electrically connected to the blank portion of the second electrode having the first polarity, and whose peripheral edge is coupled to the side wall of the battery housing, The sealing body includes a non-polarized cap plate and a gasket that wraps around the periphery of the cap plate and is crimped to the open end of the battery housing. The battery according to claim 36, wherein the battery housing is insulatedly mounted in a through hole formed in the center of the closed end and includes a rivet terminal electrically connected to the first electrode and having the second polarity.

43. A battery pack comprising a plurality of batteries according to any one of claims 31 to 42.

44. An automobile comprising the battery pack described in claim 43.

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