CN116806392A

CN116806392A - Electrode assembly, battery pack including the same, and vehicle

Info

Publication number: CN116806392A
Application number: CN202280009703.3A
Authority: CN
Inventors: 朴种殖; 林在垣; 崔惟瑆; 金学均; 李帝俊; 李炳九; 柳德铉; 李宽熙; 李宰恩; 朴必圭; 皇甫光洙; 金度均; 闵建宇; 林惠珍; 赵敏起; 崔修智; 姜宝炫; 金在雄; 郑池敏; 孔镇鹤
Original assignee: LG Energy Solution Ltd
Current assignee: LG Energy Solution Ltd
Priority date: 2021-01-19
Filing date: 2022-01-19
Publication date: 2023-09-26
Also published as: CN116783771A; CN116711149A

Abstract

An electrode assembly and a battery, and a battery pack and a vehicle including the battery are disclosed. The electrode assembly is an electrode assembly in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode around a winding axis, wherein the first electrode includes a first active material portion coated with an active material layer and a first uncoated portion uncoated with the active material layer in a winding direction. At least a portion of the first uncoated portion is defined as an electrode tab. The first uncoated portion may include: a first portion adjacent to the core of the electrode assembly; a second portion adjacent to an outer circumferential surface of the electrode assembly; and a third portion between the first portion and the second portion. The first portion or the second portion may have a smaller height in the winding axis direction than the third portion.

Description

Electrode assembly, battery pack including the same, and vehicle

Technical Field

The present disclosure relates to an electrode assembly, a battery pack including the battery, and a vehicle.

The application claims the benefit of the following patent applications: patent application number 10-2021-0007278 filed in korea on 1 month 19 of 2021;

Patent application number 10-2021-0022897 filed in korea on day 2 and 19 of 2021;

patent application number 10-2021-0022894 filed in korea on day 2 and 19 of 2021;

patent application number 10-2021-0022891 filed in korea on day 2 and 19 of 2021;

patent application number 10-2021-0022881 filed in korea on day 2 and 19 of 2021;

patent application number 10-2021-0024424 filed in korea on 2/23 of 2021;

patent application number 10-2021-0030300 filed in korea on 3/8 of 2021;

patent application number 10-2021-0030291 filed in korea on 3/8 of 2021;

patent application number 10-2021-0046798 filed in korea on day 4 and 9 of 2021;

patent application number 10-2021-0058183 filed in korea on 5/4 of 2021;

patent application number 10-2021-007046 filed in korea at 2021, 6 and 14;

patent application number 10-2021-0084326 filed in korea on month 6 and 28 of 2021;

patent application number 10-2021-01331225 filed in korea on day 10, month 1 of 2021;

patent application number 10-2021-01331215 filed in korea on 10/1;

patent application number 10-2021-01331205 filed in korea on 10/1;

patent application number 10-2021-01331208 filed in korea on 10/1;

patent application number 10-2021-01331207 filed in korea on day 10, month 1 of 2021;

Patent application number 10-2021-013001 filed in korea at 10.14/2021;

patent application number 10-2021-0137856 filed in korea on day 10 and 15 of 2021;

patent application number 10-2021-0142196 filed in korea on 10 months 22 of 2021;

patent application number 10-2021-0153472 filed in korea on day 11 and 9 of 2021;

patent application number 10-2021-0160823 filed in korea on day 11 and 19 of 2021;

patent application number 10-2021-0163809 filed in korea on month 11 and 24 of 2021;

patent application number 10-2021-0165866 filed in korea on 11 and 26 of 2021;

patent application number 10-2021-0172446 filed in korea on 12 months and 3 days 2021;

patent application number 10-2021-0177091 filed in korea on 12 months of 2021;

patent application number 10-2021-0194593 filed in korea on 12 months and 31 days 2021;

patent application number 10-2021-0194610 filed in korea on 12 months and 31 days 2021;

patent application number 10-2021-0194572 filed in korea on 12 months and 31 days 2021;

patent application number 10-2021-0194612 filed in korea on 12 months of 2021;

patent application number 10-2021-0194611 filed in korea on 12 months of 2021; and

patent application number 10-2022-0001802 filed in korea on 1 month 5 of 2022,

The entire disclosures of all of these patent applications are hereby incorporated by reference into the present application.

Background

A secondary battery, which is easily applicable to various product groups and has electrical characteristics such as high energy density, is widely applied not only to portable devices but also to Electric Vehicles (EVs) or Hybrid Electric Vehicles (HEVs) driven by an electric drive source.

Since these secondary batteries have a major advantage in that the use of fossil fuel can be significantly reduced and a minor advantage in that no by-products are generated by the use of energy, they are attracting attention as a new energy source for improving the eco-friendliness and energy efficiency.

The types of secondary batteries currently widely used in the art include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, and the like. The operating voltage of the unit secondary battery (i.e., the unit cell) is about 2.5V to 4.5V. Therefore, when a higher output voltage is required, the battery pack can be configured by connecting a plurality of batteries in series. Further, a plurality of batteries may be connected in parallel to form a battery pack according to the charge/discharge capacity required for the battery pack. Accordingly, the number of batteries included in the battery pack and the form of electrical connection may be differently set according to a desired output voltage and/or charge/discharge capacity.

Meanwhile, as a unit secondary battery, cylindrical, rectangular, and pouch-shaped batteries are known. In the case of a cylindrical battery, a separator serving as an insulator is interposed between a positive electrode and a negative electrode, and they are wound to form an electrode assembly in the form of a jelly-roll, which is inserted into a battery case to configure the battery. Further, a strip-shaped electrode tab may be connected to an uncoated portion of each of the positive and negative electrodes, and the electrode tab electrically connects the electrode assembly and the electrode terminal exposed to the outside. For reference, the positive terminal is a cap of a sealing body that seals an opening of the battery case, and the negative terminal is the battery case. However, according to the conventional cylindrical battery having such a structure, since current is concentrated in the strip-shaped electrode tabs coupled to the uncoated portion of the positive electrode and/or the uncoated portion of the negative electrode, a large resistance and a large amount of heat are generated, and the current collection efficiency is not good.

For small cylindrical cells with a shape factor of 1865 (diameter: 18mm, height: 65 mm) or 2170 (diameter: 21mm, height: 70 mm), resistance and heat are not major problems. However, when the form factor is increased to apply the cylindrical battery to an electric vehicle, the cylindrical battery may fire when a large amount of heat is generated around the electrode tab during the rapid charging process.

In order to solve this problem, there is provided a cylindrical battery (so-called tab-less cylindrical battery) in which an uncoated portion of a positive electrode and an uncoated portion of a negative electrode are designed to be positioned at the top and bottom of a jelly-roll type electrode assembly, respectively, and a current collector is welded to the uncoated portion to improve current collecting efficiency.

Fig. 1 to 3 are diagrams illustrating a process of manufacturing a tab-less cylindrical battery. Fig. 1 shows the structure of an electrode, fig. 2 shows a process of winding the electrode, and fig. 3 shows a process of welding a current collecting plate to a bent surface region of an uncoated portion.

Referring to fig. 1 to 3, the positive electrode 10 and the negative electrode 11 have a structure in which a sheet-shaped current collector 20 is coated with an active material 21 and includes an uncoated portion 22 at one long side in a winding direction X. The long side is a direction parallel to the X-axis direction, and refers to a side of a relatively long length.

As shown in fig. 2, an electrode assembly a is manufactured by sequentially stacking a positive electrode 10 and a negative electrode 11 with two separators 12 and then winding them in one direction X. At this time, the uncoated portions of the positive electrode 10 and the negative electrode 11 are arranged in opposite directions.

After the winding process, the uncoated portion 10a of the positive electrode 10 and the uncoated portion 11a of the negative electrode 11 are bent toward the core. Thereafter, the current collectors 30, 31 are welded and connected to the uncoated portions 10a, 11a, respectively.

The electrode tabs are not separately coupled to the positive electrode non-coating portion 10a and the negative electrode non-coating portion 11a, the current collectors 30, 31 are connected to external electrode terminals, and the current path is formed to have a large cross-sectional area in the winding axis direction (see arrow) of the electrode assembly a, which has an advantage of reducing the resistance of the battery. This is because the resistance is inversely proportional to the cross-sectional area of the path through which the current flows.

In the non-joint cylindrical battery, in order to improve the welding characteristics of the non-coated portions 10a, 11a and the current collectors 30, 31, it is necessary to apply a strong pressure to the welding area of the non-coated portions 10a, 11a to bend the non-coated portions 10a, 11a as flat as possible.

However, when the welding area of the uncoated portions 10a, 11a is bent, the shape of the uncoated portions 10a, 11a may be irregularly distorted and deformed. In this case, the deformed portion may be in contact with the electrode of the opposite polarity, thereby causing an internal short circuit or causing microcracks in the uncoated portions 10a, 11 a. In addition, when the uncoated portion 32 adjacent to the core of the electrode assembly a is bent, all or most of the cavity 33 in the core of the electrode assembly a is blocked. In this case, a problem in the electrolyte injection process is caused. That is, the cavity 33 in the core of the electrode assembly a serves as a passage for injecting electrolyte. However, if the corresponding channels are blocked, it is difficult to inject the electrolyte. Further, when the electrolyte injector is inserted into the cavity 33, the electrolyte injector may interfere with the uncoated portion 32 near the core, which may cause the uncoated portion 32 to be torn.

Further, the bent portions of the non-coating portions 10a, 11a for welding the current collectors 30, 31 should overlap in a plurality of layers, and there should not be any empty space (gap). In this way, a sufficient welding strength can be obtained, and even with the latest technology such as laser welding, it is possible to prevent laser light from penetrating into the electrode assembly a and melting the separator or the active material.

Meanwhile, in the conventional tab-less cylindrical battery, the positive electrode non-coating portion 10a is entirely formed on the upper portion of the electrode assembly a. Therefore, when the outer circumference of the top of the battery case is pressed inward to form the beading portion, the top edge region 34 of the electrode assembly a is compressed by the battery case. This compression may cause local deformation of electrode assembly a, which may tear separator 12 and cause internal shorting. If a short circuit occurs inside the battery, the battery may be heated or exploded.

Disclosure of Invention

Technical problem

The present disclosure is directed to solving the problems of the prior art, and therefore, the present disclosure is directed to providing an electrode assembly having an improved uncoated portion structure to relieve stress applied to an uncoated portion when the uncoated portion exposed at both ends of the electrode assembly is bent.

The present disclosure is also directed to providing an electrode assembly in which an electrolyte injection channel is not blocked even if an uncoated portion is bent.

The present disclosure is also directed to providing an electrode assembly including a structure that may prevent a top edge of the electrode assembly from contacting an inner surface of a battery case when a beading part is formed at the top of the battery case.

The present disclosure is also directed to providing an electrode assembly that improves the physical properties of a welding zone by applying a segment structure to an uncoated portion of an electrode and optimizing the dimensions (width, height, separation pitch) of the segments to substantially increase the number of overlapping layers of the segments in the region serving as the welding target zone.

The present disclosure also relates to providing an electrode assembly with improved energy density and reduced resistance by applying a structure in which a current collector is welded over a large area to a inflection surface region formed by the inflection section.

The present disclosure is also directed to providing a battery that includes a terminal and a current collector having an improved design for electrical routing at an upper portion of the battery.

The present disclosure also relates to providing a battery including an electrode assembly having an improved structure, a battery pack including the battery, and a vehicle including the battery pack.

Technical objects to be solved by the present disclosure are not limited thereto, and other objects not mentioned herein will be clearly understood by those skilled in the art from the following disclosure.

Technical proposal

In one aspect of the present disclosure, there is provided an electrode assembly in which a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode are wound based on a winding axis to define a core and an outer circumference, wherein the first electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion uncoated with the active material layer, at least a portion of the first uncoated portion itself being defined as an electrode tab, the first uncoated portion including a first portion adjacent to the core of the electrode assembly, a second portion adjacent to the outer circumference of the electrode assembly, and a third portion interposed between the first portion and the second portion, and the first portion or the second portion has a height in the winding axis direction smaller than the third portion.

In one embodiment, the third portion may be defined as the electrode tab in a state of being bent in a radial direction of the electrode assembly.

In another embodiment, the second portion and the third portion may be defined as the electrode tab in a state of being bent in a radial direction of the electrode assembly.

Preferably, at least a partial region of the third portion may be divided into a plurality of sections that are individually bendable.

Preferably, each of the plurality of sections may have a geometry of one or more straight lines, one or more curved lines, or a combination thereof.

In one embodiment, in each of the plurality of sections, the width of the lower portion may be greater than the width of the upper portion.

In another embodiment, in each of the plurality of sections, the width of the lower portion and the width of the upper portion may be the same.

In yet another embodiment, each of the plurality of sections may have a width that gradually decreases from a lower portion to an upper portion.

In yet another embodiment, each of the plurality of sections may have a width that gradually decreases and then increases from the lower portion to the upper portion.

In yet another embodiment, each of the plurality of sections may have a width that gradually increases and then decreases from the lower portion to the upper portion.

In yet another embodiment, each of the plurality of sections may have a width that gradually increases from a lower portion to an upper portion and then remains constant.

In yet another embodiment, each of the plurality of sections may have a width that gradually decreases from a lower portion to an upper portion and then remains constant.

Preferably, each of the plurality of sections may have a side formed by one or more straight lines, one or more curved lines, or a combination thereof.

In one embodiment, each of the plurality of sections may have a side portion that is outwardly convex or inwardly convex.

In another embodiment, the corners of the upper portion of each of the plurality of sections may have a rounded shape.

In the present disclosure, the plurality of sections may be configured such that the geometry varies individually, in groups, or in two or more groups in one direction parallel to the winding direction.

Preferably, the plurality of sections may have lower internal angles that increase individually, in groups, or in a plurality of grouping units in one direction parallel to the winding direction.

In one embodiment, the lower internal angles of the plurality of sections may be increased in the range of 60 degrees to 85 degrees individually, in groups, or in a plurality of grouping units in the one direction parallel to the winding direction.

In another embodiment, the lower internal angle of each of the sections belonging to the same section group may be larger than the lower internal angle of each section belonging to the section group arranged closer to the core.

In another embodiment, each of the plurality of sections may have a geometry in which a width gradually decreases from a lower portion to an upper portion, and a lower inner angle (θ) of a section located in a convolution having a radius (r) based on the core of the electrode assembly may fall within an angle range of the following formula:

(D is the width of the segment in the winding direction; r is the radius of the convolutions comprising the segment; H is the height of the segment; p is the separation pitch of the segments).

In yet another embodiment, each of the plurality of sections may have a side formed from one or more straight lines, one or more curved lines, or a combination thereof.

In yet another embodiment, each of the plurality of sections has a side that is outwardly convex or inwardly convex.

In yet another embodiment, the corners of the upper portion of each of the plurality of sections have a rounded shape.

Preferably, a cutting groove may be interposed between sections adjacent to each other in the winding direction, and a lower portion of the cutting groove may include a bottom portion and a rounded portion for connecting both ends of the bottom portion to side portions of the sections on both sides of the cutting groove.

In one embodiment, the rounded portion may have a radius of curvature greater than 0 and equal to or less than 0.1mm, more preferably 0.01mm to 0.05 mm.

In another embodiment, the bottom may be flat.

In yet another embodiment, wherein a separation pitch defined as a space between two points where a line extending from the side portions of two sections located at both sides of the cutting groove and a line extending from the bottom of the cutting groove intersect may be 0.05mm to 1.00mm.

In still another embodiment, the plurality of sections may be made of aluminum foil, and a separation pitch defined as a space between two points where a line extending from the side portions of two sections located at both sides of the cutting groove and a line extending from the bottom of the cutting groove intersect may be 0.05mm to 1.00mm.

In still another embodiment, the plurality of sections may be configured such that a separation pitch defined as a space between two points at which a line extending from the side portions of two sections located at both sides of the cutting groove and a line extending from the bottom of the cutting groove intersect varies in one direction parallel to the winding direction.

In yet another embodiment, the separation pitches of the plurality of sections are varied in groups in one direction parallel to the winding direction or in two or more groups units.

In yet another embodiment, the bottom of the cutting groove may be spaced apart from the active material layer by a predetermined distance.

Preferably, a separation distance between the bottom of the cutting groove and the active material layer may be 0.2mm to 4mm.

In one embodiment, in a plurality of sections, a separation distance between the bottom of the cutting groove and the active material layer may be the same or vary in one direction parallel to the winding direction. In the latter case, the separation distances of the plurality of sections may be varied individually, in groups, or in two or more groups in one direction parallel to the winding direction.

Preferably, the bending regions of the plurality of segments in the radial direction of the electrode assembly are located in a range of 0mm to 1mm above the lower end of the cutting groove.

In yet another embodiment, in each of the plurality of sections, a circumferential angle of an arc formed by a lower end of the section based on a core center of the electrode assembly may be 45 degrees or less.

Preferably, in each of the plurality of sections, assuming that a radius of a convolution including the section is r based on a core center of the electrode assembly and a width of the section in the winding direction is D (r), D (r) may satisfy the following formula:

1≤D(r)≤(2*π*r/360°)*45°。

in still another embodiment, in each of the plurality of sections, the width D (r) in the winding direction may be gradually or stepwise increased as a radius (r) of the convolution where the section is located based on the core center of the electrode assembly increases, and vice versa.

In still another embodiment, in each of the plurality of sections, the width D (r) in the winding direction may gradually or stepwise increase and then gradually or stepwise decrease, or vice versa, as a radius (r) of the convolution where the section is located based on the core center of the electrode assembly increases.

In yet another embodiment, the circumferential angle may be substantially the same based on the core center of the electrode assembly in the plurality of sections.

In yet another embodiment, the widths of the plurality of sections in the winding direction may increase at substantially the same rate in one direction parallel to the winding direction of the electrode assembly.

Preferably, in each of the plurality of sections, as a radius (r) of a winding turn where the section is located based on the core center of the electrode assembly increases, a width in the winding direction may be gradually or stepwise increased in a range of 1mm to 11 mm.

In a further embodiment, in at least a partial region of the third portion, the height in the winding axis direction may be gradually or stepwise varied in one direction parallel to the winding direction.

Preferably, in said at least partial region of said third portion, said height in the direction of said winding axis may vary gradually or stepwise in a direction parallel to said winding direction.

Preferably, in said at least partial region of said third portion, said height in the direction of said winding axis may gradually or stepwise increase and then gradually or stepwise decrease in one direction parallel to said winding direction.

Preferably, the third portion and optionally the second portion may be divided into a plurality of regions having different heights in one direction parallel to the winding direction, and the heights of the uncoated portions in the plurality of regions may be gradually increased or gradually increased in one direction parallel to the winding direction.

In one embodiment, the first uncoated portion may include a height-variable region in which the height of the section is greater than a first height (h ₁ ) Gradually increases to the N-1 th height (h _N-1 N is a height index and is a natural number of 2 or more), in the height uniformity region, the height of the section is maintained at an nth height (h _N Is greater than h _N-1 )。

Preferably, the N may be a natural number of 2 to 30.

In one embodiment, height h _k (k is a natural number of 1 to N) can be allocated to a plurality of sections and has the height h _k May be provided in at least one convolution.

In another embodiment, when included with a height h _k The starting radius of the convolutions of the section (k is a natural number from 1 to N) is defined as r _k The core of the electrode assembly may not be located at the r by at least 90% or more of its diameter _k The bent part of the section is covered.

In yet another embodiment, when included with a height h _k The starting radius of the convolutions of the section (k is a natural number from 1 to N) is defined as r _k And the radius of the core is r _c At the same time, the height h of the section _k The following formula may be satisfied:

2mm≤h _k ≤r _k -α*r _c (alpha is 0.90 to 1).

Preferably, the electrode assembly may sequentially include a segment skip region having no segments, a height variable region in which segments have variable heights, and a height uniform region in which segments have uniform heights, in a radial direction based on a section along the winding axis direction, and the plurality of segments may be disposed in the height variable region and the height uniform region, and the plurality of segments may be bent in the radial direction of the electrode assembly to form a bent surface region.

In one embodiment, the first portion may not be divided into sections, and the section skip region may correspond to the first portion.

In another embodiment, the third portion may be divided into a plurality of sections that can be individually bent, and the height-variable region and the height-uniform region may correspond to the third portion.

In yet another embodiment, the second portion and the third portion may be divided into a plurality of sections that are individually bendable, and the height-variable region and the height-uniform region may correspond to the second portion and the third portion.

Preferably, in the height-variable region and the height-uniform region, the maximum height (h _max ) The following formula may be satisfied:

h _max ≤W _foil -W _scrap,min -W _margin,min -W _gap

(W _foil is the width of the current collector foil before forming the segments; w (W) _scrap,min Is the width corresponding to the minimum cut scrap margin when forming a section by cutting the current collector foil; w (W) _margin,min Is a width corresponding to a minimum meandering margin of the diaphragm; and W is _gap Is a width of an insulation gap between an end of the separator and an end of the second electrode facing the first electrode with the separator interposed therebetween).

Preferably, the first electrode is a positive electrode, and the insulation gap may be in the range of 0.2mm to 6 mm.

Preferably, the first electrode is a negative electrode, and the insulation gap may be in a range of 0.1mm to 2 mm.

Preferably, wherein the minimum cutting waste margin may be in the range of 1.5mm to 8 mm.

Preferably, the minimum meandering margin may be in the range of 0mm to 1 mm. In one variation, the minimum cutting waste margin may be zero.

Preferably, the height of the section provided in the height-variable region may be gradually or stepwise increased in a range of 2mm to 10 mm.

In one embodiment, a ratio of a radial length of the segment skip region to a radius of the electrode assembly other than the core may be 10% to 40% in the radial direction of the electrode assembly.

In another embodiment, a ratio of a radial length of the height-variable region to a radial length corresponding to the height-variable region and the height-uniform region in the radial direction of the electrode assembly may be 1% to 50%.

In still another embodiment, a ratio of a length of an electrode region corresponding to the segment skip region to an entire length of the first electrode may be 1% to 30%.

In yet another embodiment, a ratio of a length of the electrode region corresponding to the height variable region to an entire length of the first electrode may be 1% to 40%.

In yet another embodiment, a ratio of a length of an electrode region corresponding to the highly uniform region to an entire length of the first electrode may be 50% to 90%.

Preferably, at least one selected from the width in the winding direction and the height in the winding axis direction of the plurality of sections may be gradually or stepwise increased in one direction parallel to the winding direction.

In one embodiment, the plurality of sections may form a plurality of section groups in one direction parallel to the winding direction of the electrode assembly, and sections belonging to the same section group may be substantially identical to each other in terms of width in the winding direction and height in the winding axis direction.

In another embodiment, the plurality of sections may form a plurality of section groups in one direction parallel to the winding direction of the electrode assembly, and sections belonging to the same section group may be substantially identical to each other in at least one aspect selected from a width in the winding direction and a height in the winding axis direction and a lower inner angle of the sections.

In still another embodiment, the plurality of segment groups may be configured such that the segments have different shapes in groups or in two or more grouping units.

In yet another embodiment, the plurality of segment groups may be configured such that the segments have different separation pitches in groups or in two or more groups units.

Preferably, at least one of the width in the winding direction, the height in the winding axis direction, and the lower internal angle thereof of the segments belonging to the same segment group may be gradually increased in one direction parallel to the winding direction of the electrode assembly.

In yet another embodiment, at least one of the width of the plurality of sections in the winding direction, the height in the winding axis direction may be gradually or stepwise increased and then gradually or stepwise decreased in one direction parallel to the winding direction, and vice versa.

In one embodiment, when widths in the winding direction of three segment groups sequentially adjacent to each other in one direction parallel to the winding direction of the electrode assembly are W1, W2, and W3, respectively, a combination of segment groups having W3/W2 less than W2/W1 may be included.

In still another embodiment, the first portion may not be divided into sections, and the first portion may not be bent in a radial direction of the electrode assembly.

In still another embodiment, the second portion may not be divided into sections, and the second portion may not be bent in a radial direction of the electrode assembly.

Preferably, an insulating coating layer may be formed at a boundary between the active material layer and a region of an uncoated portion disposed in a portion where the bottom of the cutting groove is separated from the active material layer.

In one embodiment, the insulating coating layer may include a polymer resin and an inorganic filler dispersed in the polymer resin.

In another embodiment, the insulating coating layer may be formed to cover a boundary portion of the active material layer and the first uncoated portion in the winding direction.

In still another embodiment, the insulating coating layer may be formed to cover the boundary portion of the active material layer and the first uncoated portion in a width of 0.3mm to 5mm in the winding axis direction.

In still another embodiment, an end of the insulating coating layer may be located in a range of-2 mm to 2mm in the winding axis direction based on an end of the separator.

Preferably, the insulating coating layer may be exposed outside the separator.

Preferably, the lower end of the cutting groove may be spaced apart from the insulating coating layer by a distance of 0.5mm to 2 mm.

Preferably, an end of the insulating coating layer in the winding axis direction may be located in a range of-2 mm to +2mm based on the lower end of the cutting groove.

In one embodiment, the separation distance between the bottom of the cutting groove and the active material layer may be substantially the same or vary among the plurality of sections. In the latter case, the separation distance between the bottom of the cutting groove and the active material layer may be varied individually, in groups, or in two or more groups in one direction parallel to the winding direction.

Preferably, a separation distance between the bottom of the cutting groove and the active material layer may vary in one direction parallel to the winding direction.

In one embodiment, the separation distance between the bottom of the cutting groove and the active material layer may be varied individually, in groups, or in two or more groups in one direction parallel to the winding direction.

Preferably, the second electrode may include a second active material portion coated with an active material layer along the winding direction, and an end portion of the second active material portion may be located between an upper end and a lower end of the insulating coating layer in the winding axis direction.

In yet another embodiment, the third portion and optionally the second portion may be divided into a plurality of sections that can be individually bent, and the electrode assembly may include a bending surface region formed by bending the plurality of sections in a radial direction of the electrode assembly.

Preferably, when the number of sections intersecting with a virtual line parallel to the winding axis direction at any radial position of the inflection surface region based on the core center of the electrode assembly is defined as the number of overlapping layers of sections at the corresponding radial position, the inflection surface region may include an overlapping layer number uniform region in which the overlapping layer number of sections is uniform from the core toward the outer circumference and a region of reduced overlapping layer number located outside the overlapping layer number uniform region such that the overlapping layer number of sections gradually decreases toward the outer circumference, or vice versa.

In one embodiment, the radial length of the overlapping layer number uniform region and the overlapping layer number reduced region based on the core center of the electrode assembly may correspond to the radial length of a radial region where the convolutions including the plurality of sections are located.

In another embodiment, the electrode assembly may sequentially include a segment skip region having no segments, a height variable region in which segments have variable heights, and a height uniform region in which segments have uniform heights in the radial direction, and a starting radius of the overlapping layer number uniform region based on the core center of the electrode assembly may correspond to a starting radius of the height variable region.

Preferably, in the overlapping layer number uniform region, the number of overlapping layers of the section may be 10 to 35.

In one embodiment, the first electrode may be a positive electrode, and in the overlapping layer number uniform region, the overlapping thickness of the segments may be in the range of 875 μm of 100 μm.

In another embodiment, the first electrode may be a negative electrode, and in the overlapping layer number uniform region, the overlapping thickness of the segments may be in a range of 50 μm to 700 μm.

In yet another embodiment, the ratio of the radial length of the overlapping layer number uniform region to the radial lengths of the overlapping layer number uniform region and the overlapping layer number reduced region may be 30% to 85%.

Preferably, the electrode assembly may further include: a current collector welded to the inflection surface region, and a welding region of the current collector may overlap the overlapping layer number uniformity region by at least 50% in the radial direction of the electrode assembly.

In one embodiment, a region of the welding region of the current collector, which does not overlap the overlapping layer number uniform region, may overlap the overlapping layer number reduction region in the radial direction of the electrode assembly.

In another embodiment, an edge of the current collector may be disposed on the inflection surface region to cover an end of the inflection portion of the outermost section in the radial direction of the electrode assembly and welded to the inflection surface region.

Preferably, the welding strength of the current collector and the welding region may be 2kgf/cm ² Above mentioned

More preferably, the welding strength of the current collector and the welding region may be 4kgf/cm ² The above.

In still another embodiment, the first uncoated portion may be made of a metal foil, and the elongation of the metal foil may be 1.5% to 3.0%, and the tensile strength may be 25kgf/mm ² To 35kgf/mm ² 。

Preferably, the metal foil may be an aluminum foil.

Preferably, the first electrode may have a warp length of less than 20 mm.

Preferably, in the first active material portion, a ratio of a length of a short side parallel to the winding axis direction to a length of a long side parallel to the winding direction may be 1% to 4%.

In yet another embodiment, the height of the second portion may gradually or stepwise decrease from the core of the electrode assembly toward the outer periphery.

In still another embodiment, the second portion and the third portion may be divided into a plurality of sections that are individually bendable, and the sections included in the second portion may be larger than the sections included in the third portion in at least one of a width in the winding direction and a height in the winding axis direction.

In yet another embodiment, the third portion may include a segment skip region having no segment along the winding direction of the electrode assembly.

Preferably, the third portion may include a plurality of section skip regions in one direction parallel to the winding direction.

In one embodiment, the plurality of section skip regions may have a width gradually increasing or decreasing in one direction parallel to the winding direction.

Preferably, the height of the uncoated portion of the section skip zone may be substantially the same as the height of the uncoated portion of the first portion or the uncoated portion of the second portion.

Preferably, the plurality of segments may be arranged based on a radial shape of the center of the core of the electrode assembly, and the segment skip region may be further arranged based on a radial shape of the center of the electrode assembly.

Preferably, the plurality of sections may be located within a circumferential angle range preset based on a core center of the electrode assembly.

In one embodiment, the plurality of segments may be located in at least two sector-shaped regions or polygonal-shaped regions disposed in a circumferential direction based on a core center of the electrode assembly.

Preferably, the scalloped region may have a circumferential angle of 20 degrees or more.

In still another embodiment, the second electrode may include a second active material portion coated with an active material layer and a second uncoated portion uncoated with the active material layer in the winding direction, at least a portion of the second uncoated portion may itself be defined as an electrode tab, the second uncoated portion may include an area divided into a plurality of sections that can be individually bent, and the plurality of sections may be bent in a radial direction of the electrode assembly to form a bent surface area.

In another aspect of the present disclosure, there is also provided an electrode assembly in which a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode are wound based on a winding axis to define a core and an outer circumference, wherein the first electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion uncoated with an active material layer, the first uncoated portion including a region divided into a plurality of sections that can be individually bent from the core toward the outer circumference of the electrode assembly, the plurality of sections being bent in a radial direction of the electrode assembly to form a bending surface region, and the bending surface region including an overlap amount-of-layer uniformity region in which the number of overlapping layers of the sections is 10 or more, and an overlap amount-of-layer reduction region positioned adjacent to the overlap amount uniformity region in the radial direction such that the number of overlapping layers of the sections is gradually reduced away from the overlap amount uniformity region.

In another aspect of the present disclosure, there is also provided an electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are wound based on a winding axis to define a core and an outer circumference, wherein the positive electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion not coated with an active material layer, at least a portion of the first uncoated portion itself serving as an electrode joint, the first uncoated portion including a plurality of sections individually bendable from the core of the electrode assembly toward the outer circumference, the plurality of sections being bendable and overlapping in a radial direction of the electrode assembly to form a bending surface region including an overlapping layer number uniform region in which an overlapping layer number of the sections is uniform and an overlapping layer number reduction region positioned adjacent to the overlapping layer number uniform region in the radial direction such that an overlapping amount of the sections is distant from the overlapping layer number uniform region and gradually decreases in an overlapping layer number of the sections by 5 μm between the uniform region of the overlapping layer number 875 μm.

Preferably, the electrode assembly may further include a current collector welded to the overlap layer number uniform region such that at least a portion of a welding region of the current collector overlaps the overlap layer number uniform region, and the overlap layer of a section in the welding region has a thickness in a range of 100 μm to 875 μm.

In another aspect of the present disclosure, there is also provided an electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are wound based on a winding axis to define a core and an outer circumference, wherein the negative electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion not coated with an active material layer, at least a portion of the first uncoated portion itself serving as an electrode joint, the first uncoated portion including a plurality of sections individually bendable from the core of the electrode assembly toward the outer circumference, the plurality of sections being bent and overlapped in a radial direction of the electrode assembly to form a bending surface region including an overlapped layer number uniform region in which an overlapped layer number is uniform and an overlapped layer number reduced region positioned adjacent to the overlapped layer number uniform region in the radial direction such that an overlapped layer number of the sections is distant from the overlapped layer number uniform region, and the overlapped layer number is gradually reduced in a thickness region of 700 μm between the sections.

Preferably, the electrode assembly may further include a current collector welded to the overlap layer number uniform region such that at least a portion of a welding region of the current collector overlaps the overlap layer number uniform region, and the overlap layer of a section in the welding region has a thickness ranging from 50 μm to 700 μm.

In another aspect of the present disclosure, there is also provided a battery including: an electrode assembly in which a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode are wound based on a winding axis to define a core and an outer circumference, wherein the first electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion uncoated with the active material layer, at least a portion of the first uncoated portion itself being defined as an electrode tab, the first uncoated portion including a first portion adjacent to the core of the electrode assembly, a second portion adjacent to the outer circumference of the electrode assembly, and a third portion interposed between the first portion and the second portion, and the first portion or the second portion has a height smaller than the third portion in the winding axis direction; a battery case including an open end and a bottom opposite the open end, wherein the electrode assembly is received in a space between the open end and the bottom, and the battery case is electrically connected with any one of the first electrode and the second electrode to have a first polarity; a sealing body configured to seal the open end of the battery case; and a terminal electrically connected to the other of the first electrode and the second electrode to have a second polarity and configured to have a surface exposed to the outside.

In one embodiment, the second portion may have a smaller height than the third portion in the winding axis direction, the battery case may include a beading portion press-fitted inward at a region adjacent to the open end, and an inner circumference of the beading portion facing the top edge of the electrode assembly may be spaced apart from the second portion by a predetermined distance.

Preferably, a press-in depth (D1) of the beading portion and a distance (D2) from the inner periphery of the battery case to a boundary between the second portion and the third portion may satisfy the formula d1.ltoreq.d2.

In another embodiment, the battery may further include: a current collector electrically coupled to the third portion; and an insulator configured to cover the current collector and having an edge interposed and fixed between the inner periphery of the beading portion and the current collector.

Preferably, the diameter of the current collector may be smaller than the minimum inner diameter of the inner circumference of the beading part, and the diameter of the current collector may be equal to or larger than the outermost diameter of the third part.

In another embodiment, the current collector may be located higher than the beading part in the winding axis direction.

In still another embodiment, the sealing body may include a cap configured to seal the open end of the battery case, a gasket interposed between an edge of the cap and the open end of the battery case, and a crimp bent and extending into the battery case and configured to surround and fix the edge of the cap together with the gasket, and the terminal having the second polarity may be the cap.

In yet another embodiment, the battery may further include: a first current collector electrically connected to the first uncoated portion, and the terminal may be a rivet terminal installed to be insulated from the battery case and electrically connected to the first current collector in a penetration hole formed in the bottom of the battery case to have the second polarity.

In still another embodiment, the battery may further include an insulator interposed between an inner surface of the bottom of the battery case and an upper surface of the first current collector to electrically insulate the inner surface of the bottom of the battery case from the first current collector.

Preferably, the thickness of the insulator may correspond to a distance between the inner surface of the bottom of the battery case and the upper surface of the first current collector, and the insulator is in close contact with the inner surface of the bottom of the battery case and the upper surface of the first current collector.

In still another embodiment, the terminal may include a flat portion at a lower end thereof, the insulator may have an opening for exposing the flat portion, and the flat portion may be welded to the first current collector through the opening.

In still another embodiment, the second electrode may include a second active material portion coated with an active material layer in the winding direction and a second uncoated portion uncoated with an active material layer, the second electrode may have the first polarity, at least a portion of the second uncoated portion may itself be defined as an electrode tab, and the battery may further include a second current collector electrically connected to the second uncoated portion and having an edge at least partially coupled to a sidewall of the battery case.

In still another embodiment, the second electrode may include a second active material portion coated with an active material layer in the winding direction and a second uncoated portion uncoated with an active material layer, the second electrode may have the first polarity, at least a portion of the second uncoated portion may itself be defined as an electrode tab, and the battery may further include a second current collector electrically connected to the second uncoated portion and having an edge at least partially coupled to a sidewall of the battery case, and an outer diameter of the first current collector may be equal to or greater than an outer diameter of the second current collector.

Preferably, the first and second current collectors may be welded to the first and second uncoated portions, respectively, in a radial direction of the electrode assembly to form a welding pattern, and a length of the welding pattern of the first current collector may be longer than a length of the welding pattern of the second current collector.

Preferably, the welding pattern of the first current collector and the welding pattern of the second current collector may be located at substantially the same distance from a core center of the electrode assembly.

Preferably, the battery case may include a beading portion press-fitted inward at an inner wall adjacent to the open end, and the edge of the second current collector may be electrically connected to the beading portion.

Preferably, a region of the second current collector electrically contacting the second uncoated portion may be further inward than an inner circumference of the beading portion.

In yet another embodiment, the battery may include: a cap having an edge supported by the beading portion and having no polarity; a gasket interposed between the edge of the cap and the open end of the battery case; and a crimping portion bent and extending into the open end of the battery case and configured to surround and fix the edge of the cap together with the gasket. Preferably, the edge of the second current collector may be interposed and fixed between the crimping part and the gasket by means of the crimping part.

Preferably, the edge of the second current collector may be welded to the beading part.

In another aspect of the present disclosure, there is also provided a battery including: an electrode assembly in which a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode are wound based on a winding axis to define a core and an outer circumference, wherein the first electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion uncoated with an active material layer, the first uncoated portion includes a region divided into a plurality of sections individually bendable from the core of the electrode assembly toward the outer circumference, the plurality of sections are bent in a radial direction of the electrode assembly to form a bending surface region, and the bending surface region includes an overlapping layer number uniform region in which the number of overlapping layers of the sections is 10 or more, and an overlapping layer number reduction region positioned adjacent to the overlapping layer number uniform region in the radial direction such that the number of overlapping layers of the sections gradually decreases away from the overlapping layer number uniform region; a battery case including an open end and a bottom opposite the open end, wherein the electrode assembly is received in a space between the open end and the bottom, and the battery case is electrically connected with any one of the first electrode and the second electrode to have a first polarity; a sealing body configured to seal the open end of the battery case; and a terminal electrically connected to the other of the first electrode and the second electrode to have a second polarity and configured to have a surface exposed to the outside.

In another aspect of the present disclosure, there is also provided a battery including: an electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are wound based on a winding axis to define a core and an outer circumference, wherein the positive electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion uncoated with an active material layer, at least a portion of the first uncoated portion itself serving as an electrode tab, the first uncoated portion including a plurality of sections individually bendable from the core toward the outer circumference of the electrode assembly, the plurality of sections being bent in a radial direction of the electrode assembly and overlapping into a plurality of layers to form a bending surface region, the bending surface region including an overlapping layer number uniform region in which an overlapping layer number of the sections is uniform and a overlapping layer number uniform region positioned adjacent to the overlapping layer number uniform region in the radial direction such that the amount of the sections is gradually reduced away from the overlapping layer number uniform region and a number of overlapping layers 87m is gradually reduced between the overlapping layer number uniform region and a thickness of the sections of 100 μm; a battery case including an open end and a bottom opposite the open end, wherein the electrode assembly is received in a space between the open end and the bottom, and the battery case is electrically connected with any one of the first electrode and the second electrode to have a first polarity; a sealing body configured to seal the open end of the battery case; and a terminal electrically connected to the other of the first electrode and the second electrode to have a second polarity and configured to have a surface exposed to the outside.

Preferably, the battery may further include a current collector welded to the overlap layer number uniform region such that at least a portion of a welding region of the current collector overlaps the overlap layer number uniform region, and the overlap layer of a section in the welding region has a thickness in a range of 100 μm to 875 μm.

In another aspect of the present disclosure, there is also provided a battery including: an electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are wound based on a winding axis to define a core and an outer circumference, wherein the negative electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion not coated with an active material layer, at least a portion of the first uncoated portion itself serving as an electrode tab, the first uncoated portion including a plurality of sections individually bendable from the core of the electrode assembly toward the outer circumference, the plurality of sections being bent in a radial direction of the electrode assembly and overlapping into a plurality of layers to form a bending surface region including an overlapping layer number uniform region in which an overlapping amount of the sections is uniform and an overlapping layer number uniform region positioned adjacent to the overlapping layer number uniform region in the radial direction such that the number of layers of the sections is gradually reduced away from the overlapping uniform region and a number of layers of the overlapping layer is gradually reduced to 700 μm in the overlapping layer number uniform region between the sections; a battery case including an open end and a bottom opposite the open end, wherein the electrode assembly is received in a space between the open end and the bottom, and the battery case is electrically connected with any one of the first electrode and the second electrode to have a first polarity; a sealing body configured to seal the open end of the battery case; and a terminal electrically connected to the other of the first electrode and the second electrode to have a second polarity and configured to have a surface exposed to the outside.

Preferably, the battery may further include a current collector welded to the overlap layer number uniform region such that at least a portion of a welding region of the current collector overlaps the overlap layer number uniform region, and the overlap layer of a section in the welding region has a thickness in a range of 50 μm to 700 μm.

In another aspect of the present disclosure, there is also provided a battery pack including a plurality of the above-described batteries.

Preferably, the ratio of the diameter to the height of the battery may be greater than 0.4.

Preferably, the battery may have a form factor of 46110, 4875, 48110, 4880 or 4680.

Preferably, the battery may have a resistance of less than 4 milliohms.

According to an embodiment, in the battery pack, the plurality of cells may be arranged in a predetermined number of columns such that the electrode terminal of each cell and the outer surface of the bottom of the cell case of each cell face upward.

According to another embodiment, the battery pack may further include a plurality of bus bars configured to connect the plurality of batteries in series and parallel.

Preferably, the plurality of bus bars may be disposed at upper portions of the plurality of batteries, and each of the bus bars may include: a body portion configured to extend between terminals of adjacent cells; a plurality of first bus bar terminals configured to extend from one side of the body portion and to be electrically coupled to electrode terminals of a battery located at one side; and a plurality of second bus bar terminals configured to extend from the other side of the body portion and to be electrically coupled to an outer surface of the bottom portion of the battery case of the battery located at the other side.

In another aspect of the present disclosure, there is also provided a vehicle including the battery pack.

Advantageous effects

According to one embodiment of the present disclosure, since the uncoated portions protruding from the upper and lower parts of the electrode assembly themselves serve as electrode tabs, it is possible to reduce the internal resistance of the battery and increase the energy density.

According to another embodiment of the present disclosure, since the structure of the uncoated portion of the electrode assembly is improved such that the electrode assembly does not interfere with the inner circumference of the battery in the process of forming the beading portion of the battery case, it is possible to prevent a short circuit in the cylindrical battery caused by the local deformation of the electrode assembly.

According to still another embodiment of the present disclosure, since the structure of the uncoated portion of the electrode assembly is improved, it is possible to prevent the uncoated portion from being torn when bent, and the number of overlapping layers of the uncoated portion is sufficiently increased to improve the welding strength of the current collector.

According to still another embodiment of the present disclosure, by applying a segment structure to an uncoated portion of an electrode and optimizing the size (width, height, separation pitch) of the segments to sufficiently increase the number of overlapping layers of the segments in the region serving as a welding target region, physical properties of the region where the current collector is welded may be improved.

According to still another embodiment of the present disclosure, an electrode assembly having improved energy density and reduced resistance may be provided by applying a structure in which a current collector is welded over a large area to a bent surface region formed by a bent section.

According to still another embodiment of the present disclosure, a cylindrical battery having an improved design may be provided for electrical wiring at an upper portion thereof.

According to still another embodiment of the present disclosure, since the structure of the uncoated portion adjacent to the core of the electrode assembly is improved, blocking of the cavity in the core of the electrode assembly when the uncoated portion is bent can be prevented. Therefore, the electrolyte injection process and the process of welding the battery case (or terminal) with the current collector can be easily performed.

According to still another embodiment of the present disclosure, a cylindrical battery having a structure of low internal resistance, preventing internal short circuits, and improving welding strength between a current collector and an uncoated portion, and a battery pack and a vehicle including the same may be provided.

In particular, the present disclosure may provide a cylindrical battery having a diameter to height ratio of 0.4 or more and a resistance of 4 milliohms (mohm) or less, and may provide a battery pack and a vehicle including the same.

Furthermore, the present disclosure may have several other effects, and such effects will be described in each embodiment, or any description for effects that can be easily inferred by those skilled in the art will be omitted.

Drawings

The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, help to further understand the technical features of the present disclosure, and thus the present disclosure is not to be construed as limited to the accompanying drawings only.

Fig. 1 is a plan view showing an electrode structure for manufacturing a conventional tab-less cylindrical battery.

Fig. 2 is a diagram illustrating an electrode winding process of a conventional tab-less cylindrical battery.

Fig. 3 is a diagram showing a process of welding a current collector to a bent surface area of an uncoated portion in a conventional tab-less cylindrical battery.

Fig. 4 is a plan view illustrating an electrode structure according to a first embodiment of the present disclosure.

Fig. 5 is a plan view illustrating an electrode structure according to a second embodiment of the present disclosure.

Fig. 6 is a plan view illustrating an electrode structure according to a third embodiment of the present disclosure.

Fig. 7a is a plan view illustrating an electrode structure according to a fourth embodiment of the present disclosure.

Fig. 7b is a diagram illustrating the definition of width, height and separation pitch of a segment according to one embodiment of the present disclosure.

Fig. 7c is a diagram illustrating an arc formed by a lower end of a section defining a width of the section based on a core center of an electrode assembly when the electrode is wound according to one embodiment of the present disclosure.

Fig. 7d is a graph showing the relationship of the heights h1, h2, h3, h4 of the sections, the core radius (rc), and the radii r1, r2, r3, r4 of the convolutions of the sections starting to appear, according to one embodiment of the present disclosure.

Fig. 7e is a graph of a maximum value (hmax) for determining the height (H) of a zone in the zone's height variable region.

Fig. 7f is a schematic diagram showing a formula for determining the lower internal angle (θ) of a segment.

Fig. 7g is a plan view showing a modified structure of an electrode according to a fourth embodiment of the present disclosure.

Fig. 7h is a top plan view illustrating individual regions in which multiple sections may be positioned when an electrode according to a variation of the present disclosure is wound into an electrode assembly.

Fig. 8a is a plan view illustrating an electrode structure according to a fifth embodiment of the present disclosure.

Fig. 8b is a diagram illustrating the definition of width, height and separation pitch of a segment according to another embodiment of the present disclosure.

Fig. 8c is a plan view showing a modified structure of an electrode according to a fifth embodiment of the present disclosure.

Fig. 9 is a diagram showing a section structure according to various modifications of the present disclosure.

Fig. 10a is a view showing a cross section of a bent surface region formed by bending a segment toward a core of an electrode assembly.

Fig. 10b is a top perspective view schematically illustrating an electrode assembly in which a inflection surface region is formed.

Fig. 10c is a graph showing the result obtained by counting the number of overlapping layers of sections in the radial direction in the bent surface region of the positive electrode formed at the upper portion of the electrode assembly according to examples 1-1 to 1-7.

Fig. 10d is a graph showing the result obtained by counting the number of overlapping layers of the sections measured in the radial direction in the bent surface region of the positive electrode formed at the upper portion of the electrode assembly according to examples 2-1 to 2-5, examples 3-1 to 3-4, examples 4-1 to 4-3, and examples 5-1 and 5-2.

Fig. 10e is a graph showing the result obtained by counting the number of overlapping layers of sections measured in the radial direction in the bent surface region of the positive electrode formed at the upper portion of the electrode assembly according to examples 6-1 to 6-6 and examples 7-1 to 7-6.

Fig. 10f is a top plan view of an electrode assembly according to an embodiment of the present disclosure, showing overlapping layer number uniform regions b1 and overlapping layer number reduced regions b2 in the inflection surface regions of the segments.

Fig. 11 is a sectional view showing a jelly-roll type electrode assembly in which the first electrode (positive electrode) and the second electrode (negative electrode) apply the electrodes of the first embodiment, as taken along the Y-axis direction (winding axis direction).

Fig. 12 is a sectional view showing a jelly-roll type electrode assembly in which the first electrode (positive electrode) and the second electrode (negative electrode) apply the electrode of the second embodiment, as taken along the Y-axis direction (winding axis direction).

Fig. 13 is a cross-sectional view showing a jelly-roll type electrode assembly in which any one of the electrodes of the third to fifth embodiments (modifications thereof) is applied to a first electrode (positive electrode) and a second electrode (negative electrode) as taken along the Y-axis direction (winding axis direction).

Fig. 14 is a cross-sectional view illustrating an electrode assembly according to still another embodiment of the present disclosure, taken along the Y-axis direction (winding axis direction).

Fig. 15 is a cross-sectional view illustrating an electrode assembly according to still another embodiment of the present disclosure, taken along the Y-axis direction (winding axis direction).

Fig. 16 is a cross-sectional view illustrating an electrode assembly according to still another embodiment of the present disclosure, taken along the Y-axis direction (winding axis direction).

Fig. 17 is a sectional view illustrating a cylindrical battery according to an embodiment of the present disclosure, taken along the Y-axis direction.

Fig. 18 is a sectional view illustrating a cylindrical battery according to another embodiment of the present disclosure, taken along the Y-axis direction.

Fig. 19 is a sectional view illustrating a cylindrical battery according to still another embodiment of the present disclosure, taken along the Y-axis direction.

Fig. 20 is a sectional view illustrating a cylindrical battery according to still another embodiment of the present disclosure, taken along the Y-axis direction.

Fig. 21 is a sectional view illustrating a cylindrical battery according to still another embodiment of the present disclosure, taken along the Y-axis direction.

Fig. 22 is a sectional view illustrating a cylindrical battery according to still another embodiment of the present disclosure, taken along the Y-axis direction.

Fig. 23 is a sectional view illustrating a cylindrical battery according to still another embodiment of the present disclosure, taken along the Y-axis direction.

Fig. 24 is a sectional view illustrating a cylindrical battery according to still another embodiment of the present disclosure, taken along the Y-axis direction.

Fig. 25 is a sectional view illustrating a cylindrical battery according to still another embodiment of the present disclosure, taken along the Y-axis direction.

Fig. 26 is a top plan view illustrating a structure of a first current collector according to an embodiment of the present disclosure.

Fig. 27 is a top plan view illustrating a structure of a second current collector according to an embodiment of the present disclosure.

Fig. 28 is a top plan view showing a state in which a plurality of cylindrical batteries are electrically connected.

Fig. 29 is a partial enlarged view of fig. 28.

Fig. 30 is a diagram schematically illustrating a battery pack according to an embodiment of the present disclosure.

Fig. 31 is a diagram schematically illustrating a vehicle including a battery pack according to an embodiment of the present disclosure.

Detailed Description

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

Accordingly, the description set forth herein is for the purpose of illustration only and is not intended to limit the scope of the present disclosure, so that it should be understood that other equivalents and modifications may be made to the description without departing from the scope of the present disclosure.

Moreover, in the drawings, some components have not been drawn to scale and their size may be exaggerated to aid in the understanding of the present invention. Furthermore, in different embodiments, the same components may be given the same reference numerals.

When two objects are interpreted to be identical, this means that the objects are "substantially identical". Thus, substantially identical objects may include deviations that are considered low in the art, e.g., deviations within 5%. Furthermore, when it is explained that certain parameters are uniform in a region, this may mean that the parameters are uniform in average in the corresponding region.

Although the terms first, second, etc. may be used to describe various elements, these elements should not be limited by the terms. These terms are used to distinguish one element from another element, and a first element may be a second element unless otherwise indicated.

Throughout the specification, each element may be in the singular or the plural unless otherwise indicated.

When an element is "above (or below)" or "on (or below)" another element, the element may be on an upper surface (or lower surface) of the other element, and intervening elements may be present between the one element and the other element on (or below) the element.

In addition, when an element is referred to as being "connected," "coupled," or "linked" to another element, it can be directly connected or coupled to the other element, but it is understood that there can be intermediate elements between each element or each element can be "connected," "coupled," or "linked" to each other via the other element.

Throughout the specification, "a and/or B" means a or B or both a and B unless explicitly stated otherwise, and "C to D" means C or above and D or below unless explicitly stated otherwise.

For convenience of description, a direction along a length direction of a winding axis of the electrode assembly wound in a roll shape is referred to herein as an axis direction Y. Further, the direction about the winding axis is referred to herein as the peripheral direction or peripheral direction X. Furthermore, the direction approaching or departing from the winding axis is referred to as radial direction. Among these, in particular, a direction approaching the winding axis is referred to as a centripetal direction, and a direction departing from the winding axis is referred to as an eccentric direction.

First, an electrode assembly according to one embodiment of the present disclosure will be described. The electrode assembly may be a jelly-roll type electrode assembly in which a first electrode and a second electrode having a sheet shape and a separator interposed between the first electrode and the second electrode are wound in one direction. However, the present invention is not limited to a specific kind of electrode assembly.

Preferably, at least one of the first electrode and the second electrode includes an uncoated portion whose long-side end in the winding direction is not coated with the active material. At least a portion of the uncoated portion itself serves as an electrode tab. The uncoated portion includes: a core-side uncoated portion adjacent to the core of the electrode assembly; an outer circumference non-coating part adjacent to the outer circumference of the electrode assembly; and an intermediate uncoated portion interposed between the core-side uncoated portion and the outer peripheral uncoated portion.

Preferably, at least one of the core-side uncoated portion and the outer peripheral uncoated portion has a relatively lower height than the intermediate uncoated portion.

Fig. 4 is a plan view showing the structure of an electrode 40 according to the first embodiment of the present disclosure.

Referring to fig. 4, an electrode 40 of the first embodiment includes: a current collector 41 made of a metal foil; and an active material layer 42. The metal foil may be a metal having conductivity (e.g., aluminum or copper), and is appropriately selected according to the polarity of the electrode 40. An active material layer 42 is formed on at least one surface of the current collector 41. The active material layer 42 is formed along the winding direction X. The electrode 40 includes an uncoated portion 43 at a long-side end in the winding direction X. The uncoated portion 43 is a partial region of the current collector 41 where the active material is not coated. The region of the current collector 41 where the active material is formed may be referred to as an active material portion.

In the electrode 40, the width of the active material portion in the direction along the short side of the current collector 41 may be 50mm to 120mm, and the length of the active material portion in the direction along the long side of the current collector 41 may be 3m to 5m. Thus, the ratio of the short side to the long side of the active material portion may be 1% to 4%.

Preferably, in the electrode 40, the width of the active material portion in the short side direction along the current collector 41 may be 60mm to 70mm, and the length of the active material portion in the long side direction along the current collector 41 may be 3m to 5m. Therefore, the ratio of the short side to the long side of the active material portion may be 1.2% to 2.3%.

The ratio of the short side to the long side of the active material portion is significantly smaller than that of the active material portion in an electrode used in a cylindrical battery having a shape factor of 1865 or 2170, the latter being 6% to 11%.

Preferably, the current collector 41 may have an elongation of 1.5% to 3.0% and 25kgf/mm ² To 35kgf/mm ² Tensile strength of (c). Elongation and tensile strength can be measured according to the measurement method of IPC-TM-650. The electrode 40 is manufactured by forming the active material layer 42 on the current collector 41 and then compressing it. During compression, the region of the uncoated portion 43 and the region of the active material layer 42 have different extensionsLong rate. Thus, after compression, the electrode 40 swells, and the longer the electrode 40, the more severe the swelling.

When the length of the electrode 40 is about 4m, optimization of the elongation and tensile strength of the current collector 41 reduces the warp length after compression to less than 20mm. When expanding the expanded electrode 40, the warp length is the maximum deflection of the electrode 40 in the winding direction X. The maximum deflection can be measured at the peripheral end. The electrode 40 in which the elongation and tensile strength of the current collector 41 are optimized has a small warp length so that there is no meandering defect when the electrode 40 is grooved or wound around the uncoated portion 43.

Current collector 41 tends to be prone to breakage due to the small elongation. When the elongation of the current collector 41 is less than 1.5%, the rolling process efficiency of the current collector 41 is deteriorated, and thus when the electrode 40 coated with the active material layer 42 is compressed onto the current collector 41, the current collector 41 may be broken. Meanwhile, when the elongation of the current collector 41 exceeds 3.0%, the active material portion of the electrode 40 is elongated more, and thus the warp length is significantly increased. When the tensile strength of the current collector 41 is less than 25kgf/mm ² Or greater than 35kgf/mm ² When this occurs, the electrode processing efficiency of the electrode 40 is deteriorated.

In a positive electrode current collector made of aluminum foil, the warpage phenomenon is particularly problematic. According to the present disclosure, if an elongation of 1.5% to 3.0% and a tensile strength of 25kgf/mm is used ² To 35kgf/mm ² The aluminum foil of (a) is used as a current collector, and thus the warping phenomenon can be suppressed. Preferably, an active material layer is formed on the current collector to serve as a positive electrode.

Preferably, an insulating coating layer 44 may be formed at a boundary between the active material layer 42 and the non-coating portion 43. The insulating coating layer 44 is formed such that at least a portion thereof overlaps with the boundary between the active material layer 42 and the uncoated portion 43. The insulating coating layer 44 prevents a short circuit between two electrodes having different polarities and facing each other with a separator interposed therebetween. The insulating coating layer 44 has a width of 0.3mm to 5mm, and thus may cover the boundary portion of the active material layer 42 and the uncoated portion 43. The width of the insulating coating layer 44 may vary in the winding direction of the electrode 40. The insulating coating layer 44 contains a polymer resin And may contain an inorganic filler such as Al ₂ O ₃ . The portion of the current collector 41 covered by the insulating coating layer 44 is not a region coated with the active material layer, and thus may be regarded as an uncoated portion.

The uncoated portion 43 may include: a core-side uncoated portion B1 adjacent to the core side of the electrode assembly; an outer circumference non-coating part B3 adjacent to the outer circumference side of the electrode assembly; and an intermediate uncoated portion B2 interposed between the core-side uncoated portion B1 and the outer peripheral uncoated portion B3.

The core-side uncoated portion B1, the outer peripheral uncoated portion B3, and the intermediate uncoated portion B2 may be defined as an uncoated portion of a region adjacent to the core, an uncoated portion of a region adjacent to the outer periphery, and an uncoated portion of a remaining region other than the above regions, respectively, when the electrode 40 is wound into a rolled core type electrode assembly.

Hereinafter, the core-side uncoated portion B1, the outer peripheral uncoated portion B3, and the intermediate uncoated portion B2 will be referred to as a first portion, a second portion, and a third portion, respectively.

In one embodiment, the first portion B1 may be an uncoated portion of the electrode region including the innermost convolution, and the second portion may be an uncoated portion of the electrode region including the outermost convolution. The convolutions may be counted based on the core-side end of the electrode assembly.

In another embodiment, the boundary of B1/B2 may be appropriately defined as a point at which the height (or variation pattern) of the uncoated portion varies significantly from the core to the outer circumference of the electrode assembly, or a specific percentage (%) point based on the radius of the electrode assembly (e.g., 5% point, 10% point, 15% point, etc. of the radius).

The boundary of B2/B3 is a point at which the height (or variation pattern) of the uncoated portion varies significantly from the outer periphery of the electrode assembly to the core, or a specific percentage (%) point based on the radius of the electrode assembly (e.g., 85% point, 90% point, 95% point, etc. of the radius). When the boundary of B1/B2 and the boundary of B2/B3 are specified, the third portion B2 may be automatically specified.

If only the boundary of B1/B2 is specified, the boundary of B2/B3 may be appropriately selected at a point near the outer periphery of the electrode assembly. In one embodiment, the second portion may be defined as an uncoated portion of the electrode region constituting the outermost convolution. In contrast, if only the boundary of B2/B3 is specified, the boundary of B1/B2 may be appropriately selected at a point near the core of the electrode assembly. In one embodiment, the first portion may be defined as an uncoated portion of the electrode region constituting the innermost convolution.

It is not excluded that a further structure is interposed between the first portion B1 and the third portion B2. Furthermore, it is not excluded that a further structure is interposed between the third portion B2 and the second portion B3.

In the first embodiment, the height of the uncoated portion 43 is not constant, and there is a relative difference in the winding direction X. That is, the height (length in the Y-axis direction) of the second portion B3 is relatively smaller than the heights of the first portion B1 and the third portion B2. Here, the height of each portion may be an average height or a maximum height, and the same concept is applied below. The third portion B2 is longer than the first portion B1 and the second portion B3 in the winding direction.

Fig. 5 is a plan view showing the structure of an electrode 45 according to a second embodiment of the present disclosure.

Referring to fig. 5, the electrode 45 of the second embodiment is different from the electrode 45 of the first embodiment only in that the height of the second portion B3 gradually decreases toward the outer periphery, and other configurations are substantially the same.

In a modification, the second portion B3 may be transformed into a stepped shape in which the height is gradually reduced (see a broken line).

Fig. 6 is a plan view showing the structure of an electrode 50 according to a third embodiment of the present disclosure.

Referring to fig. 6, in the electrode 50 of the third embodiment, the heights of the first portion B1 and the second portion B3 are 0 or more and relatively smaller than the height of the third portion B2. Further, the heights of the first and second portions B1 and B3 may be the same or different from each other.

Preferably, the height of the third portion B2 may have a stepped shape that increases stepwise from the core to the outer periphery.

The patterns 1 to 7 classify the third portions B2 based on the positions of the height variations of the uncoated portions 43. Preferably, the number of patterns, and the height (length in the Y-axis direction) and width (length in the X-axis direction) of each pattern may be adjusted to disperse stress as much as possible during bending of the uncoated portion 43. The stress dispersion is to prevent the uncoated portion 43 from being torn when it is bent toward the core of the electrode assembly.

The width (d) of the first portion B1 is designed by applying the condition that the core of the electrode assembly is not covered when the pattern of the third portion B2 is bent toward the core _B1 ). The core means a cavity existing at the winding center of the electrode assembly.

In one embodiment, the width (d _B1 ) May increase in proportion to the bending length of the pattern 1. The bending length corresponds to the height of the bending point of the pattern based on the pattern.

Preferably, the width (d _B1 ) The radial width of the convolution formed by the first portion B1 may be set such that it is equal to or greater than the folded length of the pattern 1. In a modification, the width (d _B1 ) It may be set such that a value obtained by subtracting the radial width of the convolution formed by the first portion B1 from the folded length of the pattern 1 is less than 0 or equal to or less than 10% of the radius of the core.

In one embodiment, when electrode 60 is used to fabricate an electrode assembly of a cylindrical battery having a shape factor of 4680, the width (d _B1 ) Is set to 180mm to 350mm.

In one embodiment, the width of each pattern may be designed to constitute one or more convolutions of the electrode assembly.

In one variation, the height of the third portion B2 may have a stepped shape that then decreases from the core to the outside Zhou Zengda.

In another modification, the second portion B3 may be modified to have the same structure as the second embodiment.

In still another modification, the pattern structure applied to the third portion B2 may be extended to the second portion B3 (see the dotted line).

Fig. 7a is a plan view showing the structure of an electrode 60 according to a fourth embodiment of the present disclosure.

Referring to fig. 7a, in the electrode 60 of the fourth embodiment, the height of the first portion B1 and the second portion B3 in the winding axis (Y) direction is 0 or more and relatively smaller than the height of the third portion B2. Furthermore, the heights of the first portion B1 and the second portion B3 in the winding axis (Y) direction may be the same or different.

Preferably, at least a partial region of the third portion B2 may comprise a plurality of sections 61. The height of the plurality of sections 61 may increase stepwise from the core to the periphery. The plurality of sections 61 have a geometry that tapers in width from bottom to top. Preferably, the geometry is trapezoidal in shape. As will be explained later, the shape of the geometric figure may be modified in various ways.

The section 61 may be formed by laser grooving. The segments 61 may be formed by known metal foil cutting processes such as ultrasonic cutting or stamping.

In the fourth embodiment, in order to prevent the active material layer 42 and/or the insulating coating layer 44 from being damaged during bending of the uncoated portion 43, it is preferable to provide a predetermined gap between the bottom G (see fig. 7 b) of the cutting groove 63 between the sections 61 and the active material layer 42. This is because stress is concentrated near the bottom of the cutting groove 63 when the uncoated portion 43 is bent. The gap is preferably 0.2mm to 4mm, more preferably 1.5mm to 2.5mm. The gap may vary along the winding direction of the electrode 60. If the gap is adjusted within the corresponding numerical range, it is possible to prevent the active material layer 42 and/or the insulating coating layer 44 from being damaged near the bottom of the cutting groove 63 due to the stress generated during bending of the uncoated portion 43. In addition, the gap may prevent the active material layer 42 and/or the insulating coating layer 44 from being damaged due to tolerances during slotting or cutting of the section 61. The gap may be substantially the same or may vary in one direction parallel to the winding direction. In the latter case, the gaps of the plurality of sections may vary individually, in groups, or in two or more grouping units along one direction parallel to the winding direction. The lower end of the cutting groove 63 and the insulating coating layer 44 may be separated by 0.5mm to 2.0mm. The separation distance between the bottom of the cutting groove 63 and the insulating coating layer 44 may be substantially the same or may vary in one direction parallel to the winding direction. In the latter case, the separation distances of the plurality of sections may be varied individually, in groups, or in two or more grouping units in one direction parallel to the winding direction. When the electrode 60 is wound, an end of the insulating coating layer 44 in the winding axis (Y) direction may be located in a range of-2 mm to 2mm in the winding axis direction with respect to an end of the separator. The insulating coating layer 44 can prevent a short circuit between two electrodes having different polarities facing each other with a separator interposed therebetween, and support a bending point when the section 61 is bent. In order to improve the effect of preventing a short circuit between the two electrodes, the insulating coating layer 44 may be exposed to the outside of the separator. Further, in order to further maximize the effect of preventing the short circuit between the two electrodes, the width of the insulating coating layer 44 may be increased so that its end in the winding axis (Y) direction is located at a higher position than the lower end of the cutting groove 63. In one embodiment, an end of the insulating coating layer 44 in the winding axis direction may be located in a range of-2 mm to +2mm with respect to a lower end 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, there may be a gap between the surface of the insulating coating layer 44 and the separator.

In one aspect, the plurality of segments 61 may form a plurality of segment groups from the core to the outer periphery. The plurality of sections belonging to the same section group may be substantially identical to each other in at least one of width, height, and separation distance. The widths, heights, and separation pitches of the sections belonging to the same section group may be the same as each other.

Preferably, the widths and heights of the sections belonging to the same section group may be substantially the same.

In another embodiment, the separation pitch may be increased gradually or stepwise from the core to the outer periphery, or vice versa, in groups or in two or more groups units, in a plurality of sections.

In yet another embodiment, in multiple segments, the separation pitch may be increased gradually or stepwise from the core to the outer periphery, and then gradually or stepwise decreased, or vice versa, in groups or in two or more groups units.

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

In still another embodiment, in a plurality of sections, the gap between the bottom of the cutting groove 63 and the insulating coating layer 44 or the active material layer 42 may gradually or stepwise increase from the core to the outer circumference and then gradually or stepwise decrease, or vice versa.

Fig. 7b is a diagram showing definitions of the width (D), the height (H), and the separation pitch (P) of the trapezoidal section 61.

Referring to fig. 7b, the width (D), height (H) and separation pitch (P) of the section 61 are designed to prevent the uncoated portion 43 from being abnormally deformed while sufficiently increasing the number of overlapped layers so as to prevent the uncoated portion 43 near the bending point from being torn during bending of the uncoated portion 43 and sufficiently improve the welding strength of the uncoated portion 43.

The section 61 is bent on or above a line G passing through the lower end of the cutting groove 63. The cutting grooves 63 may allow the sections 61 to be smoothly and easily bent in the radial direction of the electrode assembly.

The width (D) of the section 61 is defined as the length between two points at which two straight lines extending from both sides 63b of the section 61 intersect with a straight line extending from the bottom 63a of the cutting groove 63. The height (H) of the section 61 is defined as the shortest distance between the uppermost side of the section 61 and a straight line extending from the bottom 63a of the cutting groove 63. The separation pitch (P) of the sections 61 is defined as the length between two points at which a straight line extending from the bottom 63a of the cutting groove 63 intersects a straight line extending from both sides 63b connected to the bottom 63 a. When side 63b and/or bottom 63a are curved, the straight line may be replaced by a tangent line extending from side 63b and/or bottom 63a at the intersection of side 63b and bottom 63 a.

Preferably, the width (D) of the section 61 is at least 1mm. If D is less than 1mm, when the section 61 is bent toward the core, an empty space (gap) may occur or a region where the sections 61 overlap insufficiently to secure welding strength.

Preferably, the width (D) of the section 61 may be adaptively adjusted according to the radius of the convolution where the section 61 is located, such that the section 61 easily overlaps in the radial direction when the section 61 is bent toward the core of the electrode assembly.

FIG. 7c is a graph showing the lower end of the width (D) of section 61 (segment D of FIG. 7 b) defined by section 61 when electrode 60 is wound according to one embodiment of the present disclosure _ab ) An arc (A) formed based on the core center O of the electrode assembly ₁ A ₂ ) Is a diagram of (a).

Referring to fig. 7c, arc (a ₁ A ₂ ) Has a length corresponding to the width (D) of the section 61, and has a circumferential angle (Φ) with respect to the core center of the electrode assembly. The circumferential angle (Φ) can be defined as the connecting arc (A) ₁ A ₂ ) Two line segments perpendicular to the passing arc (A ₁ A ₂ ) Is provided, the angle in the plane of the winding axis of (a).

When the arc of section 61 (A ₁ A ₂ ) When the lengths of the turns are identical, the circumferential angle (Φ) decreases as the radius (r) of the winding turn in which the section 61 is located increases. Conversely, when the circumferential angle (Φ) of the segment 61 is the same, as the radius (r) of the convolutions on which the segment 61 is located increases, the arc (a ₁ A ₂ ) Proportionally increasing in length.

The circumferential angle (Φ) influences the bending quality of the section 61. In the figure, solid arrows indicate the direction of force applied by bending section 61, and dashed arrows indicate the direction in which section 61 is bent. The bending direction is towards the core center O.

The circumferential angle (Φ) of the segment 61 may be preferably 45 degrees or less, and more preferably 30 degrees or less, depending on the radius (r) of the convolution where the segment 61 is located, thereby improving the uniformity of bending and preventing the occurrence of cracks.

In one aspect, the circumferential angle (Φ) of the segment 61 may be gradually or stepwise increased or decreased in the radial direction of the electrode assembly within the above-described numerical range. In another aspect, the circumferential angle (Φ) of the segment 61 may gradually or stepwise increase and then gradually or stepwise decrease in the radial direction of the electrode assembly, and vice versa, within the above-described numerical range. In another aspect, the circumferential angle (Φ) of the segment 61 may be substantially the same in the radial direction of the electrode assembly within the above-described numerical range.

According to experiments, when the circumferential angle (Φ) of the segment 61 exceeds 45 degrees, the bent shape of the segment 61 is not uniform. The force applied to the middle of the section 61 is very different from the force applied to the side, and thus the section 61 is unevenly pressed in the circumferential direction. Further, if the pressing force is increased for uniformity of bending, cracks may occur in the uncoated portion 43 in the vicinity of the cut groove 63.

In one embodiment, the circumferential angle (Φ) of the segments 61 included in the electrode 60 is substantially the same, and the width of the segments 61 may increase in proportion to the increase in the radius (r) of the convolutions in which the segments 61 are located. The term "substantially identical" means that they are identical or have a deviation of less than 5%.

For example, when the radius of the electrode assembly is 22mm, the radius of the core is 4mm, and the section 61 is disposed starting from the convolution at the point where the radius is 7mm, if the circumferential angle (Φ) of the section 61 is constant at 28.6 degrees, the width (D) of the section 61 may be proportionally increased according to the radius (r) of the convolution where the section 61 is located, as shown in table 1 below. That is, each time the radius (r) of the convolution increases by 1mm, the width of the section 61 may increase by 0.5mm at approximately the same rate.

[TABLE 1]

Preferably, the width D (r) of the section 61 located in the convolution with a radius r with respect to the core center O of the electrode assembly may be determined within the range satisfying the following formula 1.

< formula 1>

1≤D(r)≤(2*π*r/360°)*45°

Preferably, as the winding turn in which the sections are located increases based on the radius (r) of the core center of the electrode assembly, the width D (r) of each of the plurality of sections 61 in the winding direction gradually or stepwise increases, and vice versa.

In another aspect, as the winding turn in which the sections are located increases based on the radius (r) of the core center of the electrode assembly, the width D (r) of each of the plurality of sections 61 in the winding direction gradually or stepwise increases in the range of 1mm to 11mm, and vice versa.

In another aspect, as the winding turn in which the sections are located increases based on the radius (r) of the core center of the electrode assembly, the width D (r) of each of the plurality of sections 61 in the winding direction gradually or stepwise increases, and then gradually or stepwise decreases, and vice versa.

In another aspect, as the winding turn in which the sections are located increases based on the radius (r) of the core center of the electrode assembly, the width D (r) of each of the plurality of sections 61 in the winding direction gradually or stepwise increases in the range of 1mm to 11mm, and then gradually or stepwise decreases, and vice versa.

In another aspect, as the radius (r) of the convolutions in which the sections are located increases based on the core center of the electrode assembly, the rate of change of D (r) may be substantially the same or different depending on the radius (r).

In another aspect, as the radius (r) of the convolution where the section is located based on the core center of the electrode assembly increases, the rate of change of D (r) may be approximately the same or different in the range of 1mm to 11mm depending on the radius (r).

Referring again to fig. 7b, the height (H) of the section 61 may be 2mm or more. If D2 is less than 2mm, when the section 61 is bent toward the core, an empty space (gap) or a region where the sections 61 overlap insufficiently to secure welding strength may occur.

The height (H) of the section 61 may be determined by applying a condition that the section 61 does not cover the core when bending towards the core. Preferably, the height (H) of the section 61 may be adjusted so that the core may be opened to the outside by more than 90% of its diameter.

Preferably, the height (H) of the section 61 may gradually increase from the core to the outer circumference, depending on the radius of the core and the radius of the winding turn in which the section 61 is located.

In one embodiment, it is assumed that the height (H) of the section 61 increases from H as the radius of the convolutions increases ₁ To h _N Step up N steps, when the kth height of the section 61 is h _k (k is a natural number from 1 to N) comprising a height h _k Is a segment of (2)61 having a starting radius r of the convolutions of _k And the radius of the core is r _c The height h of the section 61 can be determined ₁ To h _N The following equation 2 is satisfied.

< formula 2>

2mm≤h _k ≤r _k -α*r _c (preferably, alpha is 0.90 to 1)

If the height (h _k ) If equation 2 is satisfied, even if the segment 61 is bent toward the core, 90% or more of the diameter of the core may be opened to the outside.

In one embodiment, the total convolution radius of the electrode 60 is 22mm, the height of the sections 61 starts from 3mm, each time the convolution radius including a section 61 increases by 1mm, the height of the sections 61 increases to 3mm, 4mm, 5mm and 6mm in sequence, and the height of the sections 61 (6 mm) may remain approximately the same in the remaining convolutions. That is, the radial width of the height-variable region of the section 61 is 3mm in the radius of all the convolutions, and the remaining radial region corresponds to the height-uniform region.

In this case, according to the radius (r) of the core of the electrode assembly _c ) When α is 1 and the equal sign condition is applied to the right side inequality of the above formula, the start radius r of the convolutions of the segment 61 including the heights 3mm, 4mm, 5mm and 6mm ₁ 、r ₂ 、r ₃ 、r ₄ Can be seen as shown in table 2 below.

[TABLE 2]

When the section 61 is disposed at the radial position shown in table 2, the core is not covered by the section 61 even if the section 61 is bent toward the core. Meanwhile, r is shown in Table 2 ₁ 、r ₂ 、r ₃ 、r ₄ May be offset toward the core based on the alpha value. In one embodiment, whenWhen alpha is 0.90, r ₁ 、r ₂ 、r ₃ 、r ₄ It is possible to offset 10% of the core radius towards the core. In this case, 10% of the core radius is covered by section 61 when section 61 is bent toward the core. R shown in Table 2 ₁ 、r ₂ 、r ₃ 、r ₄ Is the limit value of the position where the section 61 starts. Thus, the position of the segment 61 may be shifted a predetermined distance to the outer circumference, further to the radius shown in table 2. Fig. 7d is a schematic illustration of the height h of the section ₁ 、h ₂ 、h ₃ 、h ₄ Radius of core (r) _c ) Radius r of the convolutions beginning to emerge with section 61 ₁ 、r ₂ 、r ₃ 、r ₄ A graph of the relationship between them.

Referring to both Table 2 and FIG. 7d, for example, when the radius (r _c ) At 3m, the height is 3mm (h ₁ )、4mm(h ₂ )、5mm(h ₃ ) And 6mm (h) ₄ ) The initial radius r of the convolutions of section 61 of (a) ₁ 、r ₂ 、r ₃ And r ₄ May be 6mm, 7mm, 8mm and 9mm, respectively, and the height of the section 61 may be maintained at 6mm from a radius of 9mm to the last convolution. In addition, the radius is less than 6mm (r ₁ ) May not include section 61. In this embodiment, since the height nearest to the core C is 3mm (h ₁ ) Is located at a position of the convolutions having a radius of 6mm, so that even if the section 61 is folded toward the core C, the section 61 covers only a radial area of 3mm to 6mm and the core C is not substantially shielded. The position of segment 61 may be at the core radius (r _c ) Is offset toward core C within 10%.

In another aspect, as the winding turn in which the section 61 is located increases based on the starting radius (r) of the core center of the electrode assembly, the height of the section 61 may increase at approximately the same rate or different ranges depending on the radius (r).

Preferably, the height (H) of the section 61 may satisfy equation 2, and at the same time limit the maximum height of the section.

FIG. 7e is a graph (H) for determining the maximum value (H) of the height (H) of the section 61 in the height variable region of the section 61 _max ) A kind of electronic deviceA conceptual diagram.

Referring to fig. 7E, in the wound structure of the electrode assembly, the electrode (E ₁ ) Facing electrodes of opposite polarity in radial direction (E ₂ ) The diaphragm S is interposed between the electrodes (E ₁ ) And electrode (E) ₂ ) Between them. Electrode (E) ₁ ) Is coated with an active material layer (E _1，active ) And electrode (E) ₂ ) Is also coated with an active material layer (E _2，active ). For electrical insulation, the end (S _end ) Can be obtained from the electrode (E ₂ ) End (E) of (E) _2，end ) Further extends outwardly by a length corresponding to the length of the insulation gap (W _gap ) Corresponding to each other. Furthermore, the electrode (E) ₁ ) Is not compared with the electrode (E) ₂ ) Extends further outwardly for electrical insulation. Therefore, it is necessary to secure an insulation gap (W at the lower end of the uncoated portion 43 _gap ) Corresponding regions. Furthermore, when the electrode (E ₁ 、E ₂ ) And an end portion (S _end ) Causing the serpentine. Therefore, in order to expose the section 61 to the outside of the diaphragm S, it is necessary to expose the region (W _margin，min ) Is allocated to the uncoated portion 43. Furthermore, in order to cut the section 61, a minimum cutting scrap margin (W _scrap，min ) Assigned to the ends of the current collector foil. Thus, the maximum height (h _max ) Can be determined by the following equation 3. In formula 3, W _foil Corresponding to the width of the current collector foil before it is cut.

< formula 3>

h _max ＝W _foil -W _scrap,min -W _margin,min -W _gap

Preferably, the insulation gap (W _gap ) The first electrode may be in the range of 0.2mm to 6mm when the first electrode is a positive electrode, and may be in the range of 0.1mm to 2mm when the first electrode is a negative electrode.

Preferably, the minimum cutting scrap margin (W _scrap，min ) May be in the range of 1.5mm to 8 mm. Depending on the process of cutting section 61, minimum cuts may be disregardedMargin of cutting waste (W) _scrap，min ). For example, the cutting groove 63 may be formed such that the upper side of the section 61 coincides with the upper side of the current collector foil. In this case, W of formula 3 _scrap，min May be zero.

Preferably, the minimum winding margin (W _margin，min ) May be in the range of 0 to 1 mm.

In one embodiment, the minimum cutting waste margin (W _scrap，min ) May be 1.5mm, and the minimum meandering margin (W _margin，min ) May be 0.5mm. Under these conditions, when the width (W _foil ) Is 8mm to 12mm and has an insulation gap (W _gap ) At 0.6mm, 0.8mm and 1.0mm, the maximum height (h) of the section 61 is calculated using equation 3 _max ) The results of (2) are shown in Table 3 below.

TABLE 3

Considering table 3, the maximum height (h _max ) Set to 10mm. Therefore, in the height-variable region of the section 61, the height of the section 61 satisfies formula 2, and at the same time may be gradually or gradually increased in the radial direction of the electrode assembly in the region of 2mm to 10mm. Referring again to fig. 7b, the separation pitch (P) of the sections 61 may be adjusted in the range of 0.05 to 1 mm. If the separation pitch (P) is less than 0.05mm, cracks may occur in the uncoated portion 43 near the lower end of the cutting groove 63 due to stress when the electrode 60 is advanced during winding or the like. Meanwhile, if the separation pitch (P) exceeds 1mm, an empty space (gap) may occur or a region where the sections 61 overlap each other insufficiently to secure the welding strength when the sections 61 are bent.

Meanwhile, when the current collector 41 of the electrode 60 is made of aluminum, the separation pitch (P) is more preferably set to 0.5mm or more. When the separation pitch (P) is 0.5mm or more, even if the electrode 60 travels at a speed of 100mm/sec or more under a tensile force of 300gf or more during a winding process or the like, it is possible to prevent occurrence of cracks in the lower portion of the cutting groove 63.

According to the experimental results, when the current collector 41 of the electrode 60 is an aluminum foil having a thickness of 15 μm and the separation pitch (P) is 0.5mm or more, the lower portion of the cutting groove 63 does not develop cracks when the electrode 60 travels under the above conditions.

As shown in fig. 7b, a cutting groove 63 is interposed between two sections 61 adjacent to each other in the winding direction X. The cut groove 63 corresponds to a space created when the uncoated portion 43 is removed. Preferably, both ends of the lower portion of the cutting groove 63 have a rounded shape. That is, the cutting groove 63 includes a substantially flat bottom 63a and a rounded portion 63c. The rounded portion 63c connects the bottom 63a and the side 63b of the section 61. In a modification, the bottom 63a of the cutting groove 63 may be replaced with an arc shape. In this case, the side portions 63b of the section 61 may be smoothly connected by the arc shape of the bottom portion 63 a.

The radius of curvature of the rounded portion 63c may be preferably in the range of 0 to 0.5mm, more preferably in the range of 0 to 0.1mm, or more preferably in the range of 0.01 to 0.05 mm. When the radius of curvature of the rounded portion 63c satisfies the above numerical range, it is possible to prevent occurrence of a crack in the lower portion of the cutting groove 63 when the electrode 60 is advanced during winding or the like.

In the plurality of sections 61, the lower internal angle (θ) may increase from the core to the outer circumference. In one embodiment, the lower internal angle (θ) of the plurality of sections 61 may gradually or stepwise increase from the core to the outer circumference. The lower internal angle (θ) is an 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 section 61. When the section 61 is symmetrical in the left-right direction, the lower internal angles (θ) of the left and right sides are substantially the same.

If the radius of the electrode assembly increases, the radius of curvature increases. If the lower internal angle (θ) of the section 61 increases as the radius of the electrode assembly increases, stress generated in the radial and circumferential directions when the section 61 is bent may be relieved. Further, if the lower internal angle (θ) is increased, when the section 61 is bent, the area where it overlaps with the section 61 located on the inner side and the number of overlapping layers are also increased together, thereby ensuring uniform welding strength in the radial and circumferential directions and forming a bent surface region in a flat form.

Preferably, the lower internal angle (θ) may be determined by the radius of the convolution where the section 61 is located and the width (D) of the section 61.

Fig. 7f is a schematic diagram for explaining a formula for determining the lower internal angle (θ) of the section 61.

Referring to fig. 7f, the sides of segment 61 coincide identically with segments AE and DE, which connect the core center (E) with two endpoints a and D of segment AD, which corresponds to the width (D) of segment 61.

When the side portion of the section 61 extends in the most ideal direction, assuming that the line segment EF is approximately equal to the line segments AE and DE, the lower internal angle (θ) of the section 61 can be approximately determined according to the width (D) of the section 61 and the radius (r) of the winding turn where the section 61 is located by the following equation 4 _refer )。

< formula 4>

The angle in equation 4 is the lower internal angle (θ) of segment 61 _refer ) Is a standard angle of ideal. At the same time, there is a separation pitch (P) between adjacent sections 61 located in the same convolution. The length of the separation pitch (P) is denoted by P. Since the separation pitch (P) exists between the adjacent sections 61, the tolerance of the lower internal angle (θ) can be set to 50% of the separation pitch (P). That is, the width of the upper side BC of the section 61 may be increased by p/2 to the upper side B 'C' at maximum. The lower internal angle (θ') reflecting the tolerance can be expressed by the following equation 5. Lower internal angle (theta) _refer ) Is an ideal standard angle BAG and the lower internal angle (θ ') is an angle B ' AG ' reflecting the tolerance according to the separation pitch (P). In equation 5, H corresponds to the height of the section 61, and p corresponds to the separation pitch.

< formula 5>

Preferably, the lower internal angle (θ) of the section 61 at each convolution of the electrode assembly may satisfy the following formula 6. Then, when the sections 61 are bent toward the core center of the electrode assembly, the sections 61 adjacent in the circumferential direction do not interfere with each other and are smoothly bent.

< formula 6>

In one embodiment, when electrode 60 is formed into a rolled configuration having a diameter of 22mm and a core radius of 4mm, the lower internal angle of section 61 may be gradually or stepwise increased in the range of 60 degrees to 85 degrees in the height variable region.

In another embodiment, in the plurality of sections 61, the lower internal angle (θ) may gradually or stepwise increase from the core to the outer circumference in one or more grouping units.

Meanwhile, the lower inner angles of the sections 61 at the left and right sides may be different from each other. Nonetheless, at least one of the lower interior angles at the left and right sides of section 61 may be designed to satisfy equation 6.

Referring again to fig. 7a, the width (d _B1 ) Designed such that when the section 61 of the third portion B2 is bent toward the core, the core of the electrode assembly is open to the outside by more than 90% based on the diameter of the core. Width (d) of the first portion B1 _B1 ) May increase in proportion to the bending length of the section 61 of group 1. The bending length corresponds to the length from the bending point to the uppermost side of the section 61. Preferably, when the electrode 60 is used to manufacture an electrode assembly of a cylindrical battery having a shape factor of 4680, the width (d _B1 ) May be set to 180mm to 350mm.

The bending point of the section 61 may be set at a line passing through the lower end of the cutting groove 63 or at a point spaced a predetermined distance upward from the line. When the section 61 is bent toward the core at a point spaced a predetermined distance from the lower end of the cutting groove 63, the sections may more easily overlap in the radial direction. When the sections 61 are bent, the inner sections are pressed based on the sections of the core that are located outside the center. At this time, if the bending point is spaced apart from the lower end of the cutting groove 63 by a predetermined distance, the inner section is pressed by the outer section in the winding axis direction so that the sections overlap better. Preferably, the separation distance of the bending points may be 1mm or less. The minimum height of the section 61 is 2mm, and thus the ratio of the separation distance to the minimum height of the section 61 may be 50% or less.

In one embodiment, the width of each segment group may be designed to constitute the same convolution of the electrode assembly. Here, when the electrode 60 is in the wound state, the winding turn may be counted based on the end of the first portion B1.

In another modification, the width of each segment group may be designed to constitute at least one convolution of the electrode assembly.

In a further variant, the width and/or height and/or the separation pitch of the segments 61 belonging to the same segment group may be gradually and/or stepwise and/or irregularly increased or decreased within a group or between adjacent groups.

Groups 1 to 8 are only embodiments of the group of sections included in the third section B2. The number of groups, the number of sections 61 included in each group, and the width of each group may be desirably adjusted so that the sections 61 overlap in a plurality of layers to disperse stress as much as possible during the bending process of the uncoated portion 43 and to sufficiently secure the welding strength with the current collector.

In another modification, the height of the second portion B3 may be gradually or stepwise reduced as in the first and second embodiments.

In a further variant, the section structure of the third portion B2 can be extended to the second portion B3 (see dashed line). In this case, the second portion B3 may also include a plurality of sections as the third portion B2. Preferably, the section structure of the second portion B3 may be substantially the same as the outermost section group of the third portion B2. In this case, the sections included in the second and third portions B3 and B2 may be substantially the same in terms of width, height, and separation distance. In a variant, the width and/or height and/or separation distance of the sections of the second portion B3 may be greater than the width and/or height and/or separation distance of the third portion B2.

In the third portion B2, the region (group 1 to group 7) in which the height of the section 61 increases stepwise based on the winding direction of the electrode 60 is defined as a height-variable region of the section, and the final section group (group 8) may be defined as a height-uniform region in which the height of the section is uniformly maintained.

That is, in the third portion B2, when the height of the section 61 is from h ₁ Gradually increase to h _N When arranged with a height h ₁ To h _N-1 The region of the section 61 (N is a height index and a natural number of 2 or more) corresponds to a height variable region, and is arranged with a height h _N The area of section 61 of (a) corresponds to a highly uniform region. The ratio of the height-variable region and the height-uniform region to the length of the electrode 60 in the winding direction will be described later with reference to the specific embodiment.

When electrode 60 is used to fabricate an electrode assembly for a cylindrical battery having a form factor of 4680, the width (d _B1 ) May be 180mm to 350mm. The width of the group 1 may be 35% to 40% of the width of the first portion B1. The width of group 2 may be 130% to 150% of the width of group 1. The width of group 3 may be 120% to 135% of the width of group 2. The width of group 4 may be 85% to 90% of the width of group 3. The width of group 5 may be 120% to 130% of the width of group 4. The width of group 6 may be 100% to 120% of the width of group 5. The width of group 7 may be 90% to 120% of the width of group 6. The width of group 8 may be 115% to 130% of the width of group 7. Width (d) of the second portion B3 _B3 ) May be 180mm to 350mm, similar to the width of the first portion B1.

The reason why the widths of the first to eighth groups do not show a pattern that constantly increases or decreases is that the segment widths gradually increase from group 1 to group 8, but the number of segments included in the groups is limited to an integer, and the thicknesses of the electrodes have a slight deviation in the winding direction. Thus, the number of segments in a particular segment group may be reduced. Thus, the width of the group may show an irregularly changing pattern from the core to the outer periphery as in the above embodiment.

That is, assuming that the width in the winding direction of each of three segment groups consecutively adjacent to each other in the circumferential direction of the electrode assembly is W1, W2, and W3, respectively, a combination of segment groups in which W3/W2 is smaller than W2/W1 may be included.

In a specific embodiment, groups 4 to 6 correspond to the above. 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%, which is less than 120% to 130%.

According to another modification, when the uncoated portion 43 of the electrode 60 has a segment structure, the electrode 60 may include a segment skip region 64 in which some of the plurality of segments are regularly or irregularly omitted, as shown in fig. 7 g.

Preferably, a plurality of section skip areas 64 may be provided. In one embodiment, the width of the segment skip region 64 may be Zhou Hengding outwardly from the core. In another embodiment, the width of the section skip region 64 may be increased or decreased regularly or irregularly from the core toward the outer circumference. Preferably, the height of the uncoated portion existing in the section skip region 64 may correspond to the height of the first portion B1 and/or the second portion B3.

The number of sections 61 existing between the section skip regions 64 may be at least one. As shown in fig. 7g, the electrode 60 may include an uncoated portion in which the number of sections 61 existing between the section skip regions 64 increases from the core toward the outer circumference.

Preferably, the width of the segment skip region 64 may be set such that when the electrode 60 is wound as shown in fig. 7h, the segments located in each winding turn may be located in a preset individual region 66 with respect to the core center C of the electrode assembly 65.

That is, when the electrode assembly 65 is viewed in the winding axis direction, the plurality of sections 61 may be located within the plurality of individual regions 66 with respect to the core center C. The number of individual zones 66 may vary to 2, 3, 4, 5, etc.

Preferably, the individual regions 66 may have a fan shape. In this case, the angle between the individual regions 66 may be approximately the same. Further, the peripheral angle (δ) of the individual zones 66 may be 20 degrees or more, optionally 25 degrees or more, optionally 30 degrees or more, optionally 35 degrees or more, or optionally 40 degrees or more.

In variations, the individual regions 66 may have a geometric shape such as square, rectangular, parallelogram, trapezoid, or the like.

In the present disclosure, the shape of the section 61 may be variously modified.

Fig. 8a is a plan view showing the structure of an electrode 70 according to a fifth embodiment of the present disclosure.

Referring to fig. 8a, the electrode 70 of the fifth embodiment has substantially the same configuration as the electrode 70 of the previous embodiment except for the shape of the section 61'. Therefore, the configuration of the fourth embodiment can be equally applied to the fifth embodiment unless otherwise specified.

The geometry of section 61' has substantially the same width at the top and bottom. Preferably, the section 61' may have a rectangular shape.

Fig. 8b is a diagram showing the definition of the width, height and separation pitch of the rectangular section 61'.

Referring to fig. 8b, the width (D), the height (H), and the separation pitch (P) of the section 61' may be set to prevent the uncoated portion 43 from being abnormally deformed while increasing the number of overlapping layers of the uncoated portion 43 sufficiently so as to prevent the uncoated portion 43 from being torn at the time of bending and to improve the welding strength with the current collector. The abnormal deformation means that the uncoated portion below the bending point does not maintain a straight line state and irregularly contracts and deforms.

The width (D) of the section 61 'is defined as the length between two points where two straight lines extending from both sides of the section 61' intersect with a straight line extending from the bottom 63a of the cutting groove 63. The height (H) of the section 61 'is defined as the shortest distance between the uppermost side of the section 61' and a straight line extending from the bottom 63a of the cutting groove 63. The separation pitch (P) of the sections 61' is defined as the length between two points at which a straight line extending from the bottom 63a of the cutting groove 63 intersects a straight line extending from both sides 63b connected to the bottom 63 a. When side 63b and/or bottom 63a are curved, the straight line may be replaced by a tangent line extending from side 63b and/or bottom 63a at the intersection of side 63b and bottom 63 a.

Preferably, the conditions concerning the width (D), the height (H) and the separation pitch (P) of the section 61' are substantially the same as those of the fourth embodiment, and thus will not be described again. However, since the section 61 'has a rectangular shape, the lower internal angle of the section 61' may be constant at 90 degrees.

Similar to the electrode 60 of the fourth embodiment, the electrode 70 according to the fifth embodiment may further include a section skip region 64 in which some of the plurality of sections are regularly or irregularly omitted, as shown in fig. 8 c.

Further, when the electrode 70 including the segment skip region 64 is wound into an electrode assembly, the segments may be located within a plurality of individual regions 66, as shown in fig. 7 h.

As in the fourth and fifth embodiments, when the third and second portions B2, B3 include a plurality of sections 61, 61', the shape of each section 61, 61' may be differently modified.

Preferably, the segments may be deformed into various shapes if at least one of the following conditions is satisfied.

Condition 1: the width of the lower portion is greater than the width of the upper portion.

Condition 2: the width of the lower portion is the same as the width of the upper portion.

Condition 3: the width remains the same from bottom to top.

Condition 4: the width decreases from bottom to top.

Condition 5: the width decreases from bottom to top and then increases.

Condition 6: the width increases from bottom to top and then decreases.

Condition 7: the width increases from bottom to top and remains constant.

Condition 8: the width decreases from bottom to top and remains constant.

Condition 9: the inner angle of one side of the lower part is the same as the inner angle of the other side.

Here, the inner angle may be defined as an angle formed by the side portion of the section based on the width direction of the lower portion of the section. When the side portion is curved, the internal angle is defined as the angle between the tangent drawn at the lowermost end of the curve and the width direction of the lower portion of the section.

Condition 10: the inner angle of one side and the inner angle of the other side of the lower part are different from each other.

Condition 11: the inner angle of one side of the lower part and the inner angle of the other side of the lower part have an acute angle, a right angle or an obtuse angle respectively.

Condition 12: is bilaterally symmetrical about the winding axis direction.

Condition 13: is asymmetric left and right with respect to the winding axis direction.

Condition 14: the side portion has a straight line shape.

Condition 15: the side portions are curved.

Condition 16: the side portion is outwardly convex.

Condition 17: the side portions are inwardly convex.

Condition 18: the corners of the upper and/or lower portions have a structure in which straight lines intersect with straight lines.

Condition 19: the corners of the upper and/or lower portions have a structure in which straight lines intersect with curved lines.

Condition 20: the corners of the upper and/or lower portions have a curve-to-curve intersection configuration

Condition 21: the corners of the upper and/or lower portions have rounded configurations.

Fig. 9 is a diagram exemplarily showing the shape of a section according to a modification of the present disclosure.

As shown in the figures, the segments may have various geometries, with the dashed line connecting the bottoms of the cut grooves on both sides being the base. The geometric figure has a structure connecting one or more straight lines, one or more curved lines, or a combination thereof. In one embodiment, the segments may have a polygonal shape, a rounded shape, or various shapes in combination therewith.

In particular, the segments may have a laterally symmetrical trapezoidal shapeLeft and right asymmetric trapezoid shape ++>Parallelogram shape->Triangle shape ((1)); pentagonal shape->Arc shape->Oval shape->

Since the shape of the segment is not limited to the shape shown in fig. 9, it may be transformed into other polygonal shapes, other rounded shapes, or a combination thereof to satisfy at least one of the above-described conditions 1 to 21.

Polygonal shape in sectionAnd (1) the corners of the upper and/or lower portions may be shaped such that a straight line intersects a straight line, or may be rounded (see shape +.>An enlarged view of the upper and lower corners of (a)).

Polygonal shape in sectionAnd (1) and the curved shape of the segment +.>And->In the lower part, the inner angle (theta) ₁ ) And the inner angle (theta) of the other side thereof ₂ ) May be the same or different from each other, and the inner angle (θ) of one side of the lower portion ₁ ) And the other side thereofInternal angle (theta) ₂ ) May be any one of an acute angle, a right angle, or an obtuse angle, respectively. An interior angle is the angle at which the base and side of the geometric figure intersect. When the side portions are curved, the straight line may be replaced by a tangent line extending at the point where the base portion and the side portions meet.

The shape of the sides of the sections having a polygonal shape may be modified in various ways.

In one embodiment, the segment shapeCan be transformed as in the shape +.>The outward convex curve in (a) or transformed into a shape as in +.>Or->Is recessed into the section.

In another embodiment, the segment shapeCan be transformed as in the shape +.>Or->A straight line of bending recessed into the section. Although not shown, the section shape +.>The sides of (a) may be transformed into outwardly convex straight lines of curvature.

Section shapes differently deformed at the sidesAnd +.>In the lower part, the inner angle (theta) ₁ ) And the inner angle (theta) of the other side thereof ₂ ) May be the same or different from each other, and the inner angle (θ) of one side of the lower portion ₁ ) And the inner angle (theta) of the other side thereof ₂ ) May be any of acute angle, right angle or obtuse angle, respectively.

The width of the segments may have various patterns of variation from bottom to top.

In one embodiment, the width of the segments may be kept constant from bottom to top (shape). In another embodiment, the width of the segments may decrease gradually from bottom to top (shape +.>And +.>). In a further embodiment, the width of the segments may gradually decrease from bottom to top and then increase (shape +.>And->). In a further embodiment, the width of the segments may gradually increase from bottom to top and then decrease (shape +. >). In a further embodiment, the width of the segments may gradually decrease from bottom to top and then remain constant (shape +.>). Although not shown, the width of the segmentsMay gradually increase from bottom to top and remain constant.

Meanwhile, in the shape of the section shown in fig. 9, a polygonal shape having a flat top may be rotated 180 degrees. In one embodiment, when the segment is shapedOr->The width of the segments may gradually increase from bottom to top when rotated 180 degrees. In another embodiment, if the section shape +.>The width of the segments may remain constant from bottom to top and then gradually increase by 180 degrees.

In the above embodiment (modification), according to another aspect of the present disclosure, the shape of the sections 61, 61' may be varied differently according to the region of the third portion B2. In one embodiment, a rounded shape (e.g., semi-circular, oval, etc.) that facilitates stress distribution is applied to the region of stress concentration, and a polygonal shape (e.g., rectangular, trapezoidal, parallelogram, etc.) with the largest area may be applied to the region of relatively lower stress.

In another embodiment, the plurality of sections may have different shapes in one direction parallel to the winding direction of the electrode assembly, individually, in groups, or in two or more grouping units.

In the above embodiment (modification), the section structure of the third portion B2 is also applicable to the first portion B1. However, if a segment structure is applied to the first portion B1, when the segments 61, 61' of the third portion B2 are bent according to the radius of curvature of the core, the end of the first portion B1 may be bent toward the outer circumference, which is called reverse forming. Thus, the first portion B1 has no segments, or even if a segment structure is applied to the first portion B1, it is desirable to control the width and/or height and/or spacing of the segments 61, 61' as much as possible in consideration of the radius of curvature of the core so that reverse shaping does not occur.

According to yet another aspect of the present disclosure, after the electrode 60, 70 is wound into an electrode assembly, the sections exposed at the upper and lower portions of the electrode assembly may be overlapped in a plurality of layers in the radial direction of the electrode assembly to form a bent surface region.

Fig. 10a is a schematic diagram showing a cross section of a bending surface region F formed when the section 61 is bent toward the core C of the electrode assembly 80. In fig. 10a, only the left side of the cross section of the inflection surface region F is shown with respect to the winding axis of the electrode assembly 80. The inflection surface regions F may be formed at the upper and lower portions of the electrode assembly 80. Fig. 10b is a top perspective view schematically illustrating an electrode assembly 80 forming a inflection surface region F.

Referring to fig. 10a and 10b, the inflection surface region F has a structure in which the sections 61 overlap in the winding axis direction in a plurality of layers. The overlapping direction is the winding axis direction (Y). Region (1) is a section skip region (first portion B1) having no section, and regions (2) and (3) are regions where the convolution including section 61 is located. Region (2) is a height-variable region in which the height of section 61 is variable, and region (3) is a height-uniform region in which the height of the section remains uniform to the outer circumference of the electrode assembly. As will be described later, the radial lengths of the regions (2) and (3) may be variable. Meanwhile, the uncoated portion (second portion B3) included in at least one convolution including the outermost convolution may not include a segment structure. In this case, the second portion B3 may be excluded from the region (3).

In region (2), the height of section 61 may be within the radius region r of electrode assembly 80 ₁ To r _N From the minimum height h ₁ (＝h _min ) Stepwise to a maximum height h _N (＝h _max ). The height-variable region of section 61, which is variable in height, is r ₁ To r _N . Radius r from electrode assembly 80 _N To radius R, the height of segment 61 is uniformly maintained at h _N . Uniform height means that the height deviation is within 5%.

At any radial position of the zone (2) and the zone (3), the intersection of the sections 61The number of laminations varies depending on the radial position. Furthermore, the number of overlapping layers of the sections 61 may be based on the width of the region (2), the minimum height (h) of the sections in the height-variable region of the sections 61 ₁ ) And maximum height (h) _N-1 ) And the height variation (Δh) of the section 61. The number of overlapping layers of the sections 61 is the number of sections intersecting the virtual line when the virtual line is drawn in the winding axis direction at any radial position of the electrode assembly 80.

Preferably, the number of overlapping layers of the sections 61 at each position of the bending surface region F may be optimized to be suitable for the required welding strength of the current collector by adjusting the height, width and separation pitch of the sections 61 according to the radius of the convolutions including the sections 61.

First, when the minimum height (h) of the section in the height-variable region ((2)) of the section 61 ₁ ) In the same case, how the number of overlapping layers of the section 61 is according to the maximum height (h _N ) And along the radial direction of the inflection surface region F.

Electrode assemblies of examples 1-1 to 1-7 were prepared. The electrode assemblies of these embodiments have a radius of 22mm and a core diameter of 4 mm. The positive and negative electrodes included in the electrode assembly have the electrode structure shown in fig. 7 a. That is, the segments have a trapezoidal shape. The second portions B3 of the positive and negative electrodes have no segments. The length of the second portion B3 is 2% to 4% compared to the total length of the electrode. The positive electrode, the negative electrode, and the separator are wound by the method described with reference to fig. 2. The convolutions were between 48 and 56 turns, while the convolutions of these embodiments were 51 turns. The thicknesses of the positive electrode, the negative electrode and the separator were 149 μm, 193 μm and 13 μm, respectively. The thicknesses of the positive electrode and the negative electrode are thicknesses including the thickness of the active material layer. The thicknesses of the positive electrode current collector and the negative electrode current collector were 15 μm and 10 μm, respectively. The lengths of the positive electrode and the negative electrode in the winding direction were 3948mm and 4045mm, respectively.

In each embodiment, the minimum height of the section 61 is set to 3mm, so that the height variable region ((2)) of the section 61 starts from a radius of 5 mm. Furthermore, in each embodiment, the height of the section 61 increases by 1mm for every 1mm increase in radius, and the maximum height of the section 61 varies from 4mm to 10mm.

Specifically, in embodiment 1-1, the height-variable region ((2)) of the section 61 is 5mm to 6mm, and the height of the section 61 is variable at a radius of 3mm to 4 mm. In embodiments 1-2, the height variable area ((2)) of the section 61 is 5mm to 7mm, and the height of the section 61 may vary from 3mm to 5 mm. In embodiments 1-3, the height variable area ((2)) of the section 61 is 5mm to 8mm, and the height of the section 61 may vary from 3mm to 6 mm. In examples 1-4, the height variable area ((2)) of the section 61 was 5mm to 9mm, and the height of the section 61 was variable from 3mm to 7 mm. In embodiments 1-5, the height variable area ((2)) of the section 61 is 5mm to 10mm, and the height of the section 61 may vary from 3mm to 8 mm. In examples 1-6, the height variable area ((2)) of the section 61 was 5mm to 11mm, and the height of the section 61 was variable from 3mm to 9 mm. In embodiments 1-7, the height variable area ((2)) of the section 61 is 5mm to 12mm, and the height of the section 61 may vary from 3mm to 10mm. In embodiments 1-1 to 1-7, the height of the section 61 is uniform from the radius corresponding to the upper limit of the height-variable region ((2)) to the outer periphery. In one embodiment, in embodiments 1-7, the height of the section 61 located at a radius from 12mm to 22mm is uniformly 10mm. Meanwhile, in the electrode assembly of the comparative example, the height of the section 61 was maintained at a single height of 3mm at a radius from 5mm to 22 mm.

Fig. 10c is a graph showing the result of counting the number of overlapping layers of sections in the radial direction in the bent surface region F of the positive electrode formed on the upper portion of the electrode assembly according to examples 1-1 to 1-7 and comparative example. The inflection surface area of the negative electrode showed about the same result. The horizontal axis of the graph is based on the radius of the core center, and the vertical axis of the graph is the number of overlapping layers counted at each radius point, and is the same in fig. 10d and 10e, which will be explained later.

Referring to fig. 10c, the overlapping layer number uniformity region b1 of the sections is shown in common in examples 1-1 to 1-7 and comparative example 1. The overlapping layer number uniform region b1 is a radial region of the flat region in each graph. The length of the overlapping layer number uniformity region b1 increases as the maximum height of the section decreases, and the overlapping layer number uniformity of the comparative exampleZone (b 1') is longest. At the same time, the number of overlapping layers of the segments follows the maximum height (h _N ) Increasing and increasing. I.e. if the maximum height of the segment (h _N ) Increasing such that the width of the height-variable region ((2)) of the section increases, the number of overlapping layers of the section increases, but the width of the overlapping layer number uniform region b1 decreases. Outside the overlapping layer number uniform region b1, a overlapping layer number decreasing region b2 occurs in which the number of overlapping layers decreases with increasing radius. The overlap number reduced region b2 is a radial region in which the overlap number is reduced as the radius of the electrode assembly is increased. The overlapping layer number uniform region b1 and the overlapping layer number reduced region b2 are adjacent in the radial direction and are complementary to each other. That is, if the length of one region increases, the length of the other region decreases. Further, the amount of decrease in the number of overlapped layers in the overlapped layer number decrease region b2 is proportional to the distance spaced apart from the overlapped layer number uniform region b1.

From the viewpoint of the number of overlapped layers of the sections, in examples 1-1 to 1-7, the number of overlapped layers of the sections in the overlapped layer number uniform region b1 was 10 or more. A region where the number of overlapping layers of the segments is 10 or more may be set as a preferable welding target region. The welding target region is a region where at least a portion of the current collector may be welded.

In examples 1-1 to 1-7, the overlapping layer number uniform region b1 starts from a radius point at which the height-variable region ((2)) of the section starts. That is, the height-variable region ((2)) starts from a radius of 5mm and extends toward the outer periphery.

The following table 4 shows the following calculation results with respect to the positive electrode in examples 1-1 to 1-7 and comparative example 1: a ratio of a length of the segment skip region (c, fig. 10a (1)) to a radius (b-a) of the electrode assembly excluding the core; a ratio (e/f) of the length of the overlapping layer number uniform region b1 to the length (f) from a radius point (5 mm) of the overlapping layer number uniform region to an outermost point (22 mm) of the electrode assembly; a ratio (d/f) of a length of the height-variable region (d) of the section (d) to a length (f) from a radius point (5 mm) at which the number of overlapping layers is uniform to an outermost point (22 mm) of the electrode assembly; a ratio (h) of the length of the electrode region to the total length of the electrode corresponding to the section skip region (first portion B1); a ratio (i) of a length of the electrode region corresponding to the height-variable region to a total length of the electrode; a ratio (j) of the length of the electrode region corresponding to the highly uniform region to the total length of the electrode, and the like.

The remaining parameters were substantially the same as the positive electrode except that the negative electrode showed a difference of 0.1% to 1.2% with respect to the parameter h. The sum of the ratios h, i and j is slightly different from 100%. The reason is that there is a region without a segment in the second portion B3 corresponding to the outer peripheral uncoated portion of the electrode. For example, in example 1-1, there is no segment in the second portion B3 corresponding to approximately 4% of the total electrode length. In table 4, a to f are parameters based on the length in the radial direction, and h, i, and j are parameters based on the length in the electrode length direction before winding into an electrode assembly. Further, the parameter corresponding to the ratio (%) is a value rounded to the first decimal place. These aspects are substantially the same in tables 5 and 6 explained later.

TABLE 4

Referring to examples 1-1 to 1-7 of table 4, the number of overlapping layers of the sections was 11 to 26, and the ratio (d/f) of the height-variable region (d) to the radius region (f) including the sections was 6% to 41%. Furthermore, the ratio (e/f) of the overlapping layer number uniform region (e) to the radius region (f) including the segment is 47% to 82%. Further, the ratio (c/(b-a)) of the segment skip region (c, fig. 10a (1)) to the radius (b-a) (excluding the core) of the electrode assembly was 15%. Further, the ratio of the length of the electrode region corresponding to the segment skip region (first portion B1) to the total length of the electrode is 6%, the ratio of the length of the electrode region corresponding to the height-variable region 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 region to the total length of the electrode is 59% to 87%. The number of overlapping layers (g) of the overlapping layer number uniformity region was 10 or more for all examples 1-1 to 1-7. The overlapping layer number uniformity region (e) decreases as the height variable region (d) of the segment increases, but in the overlapping layer number uniformity region (e), the overlapping layer number (g) of the segment increases. Preferably, a crossover number uniformity region (e) in which the crossover number (g) of the segments is 10 or more may be set as the welding target region.

In the cylindrical batteries with form factors of 1865 and 2170, the radius of the electrode assembly is approximately 9mm to 10mm. Therefore, for a conventional cylindrical battery, the radial length of the segment region (f) cannot be ensured at the level of 17mm as in examples 1-1 to 1-7, and the length of the overlapping layer number uniform region (e) in which the number of overlapping layers of the segment is 10 or more cannot be ensured at the level of 8mm to 14 mm. This is because, in the conventional cylindrical battery, when the radius of the core is designed to be 2mm (as in examples 1-1 to 1-7), the radial area in which the segments can be provided is approximately only 7mm to 8mm. Further, in the conventional cylindrical battery, the length of the electrode in the winding direction is at a level of 600mm to 980 mm. Such short electrode length is only about 15% to 24% of the electrode length used in examples 1-1 to 1-7 (positive electrode 3948mm, negative electrode 4045 mm). Therefore, the numerical ranges of the parameters h, i, and j cannot be easily derived from the design specifications of the conventional cylindrical battery.

Next, when the maximum height (h _N ) When the height-variable regions of the sections are the same (fig. 10a (2)), how the number of overlapping layers of the sections is in accordance with the minimum height (h) of the sections ₁ ) But in the radial direction of the inflection surface region F.

The radius of the electrode assemblies of examples 2-1 to 2-5 was 22mm, and the diameter of the core C was 4mm. In the height-variable region of section 61 (2) in fig. 10 a), the minimum height (h ₁ ) Is identical to 4mm, and has a maximum height (h _N ) Varying from 6mm to 10mm in 1mm increments. Therefore, in the electrode assemblies of examples 2-1 to 2-5, the widths of the height-variable regions of the segments ((2) in fig. 10 a) were 2mm, 3mm, 4mm, 5mm and 6mm, respectively, and the segment skip regions ((1) in fig. 10 a) were radial regions having a radius of 2mm to 6 mm.

Radius of electrode assemblies of examples 3-1 to 3-422mm and the diameter of the core C is 4mm. In the height-variable region of the segment 61 (2) of fig. 10 a), the minimum height (h ₁ ) Is identical to 5mm, and has a maximum height (h _N ) Varying from 7mm to 10mm in 1mm increments. Therefore, in the electrode assemblies of examples 3-1 to 3-4, the widths of the segment height-variable regions ((2) in fig. 10 a) were 2mm, 3mm, 4mm and 5mm, respectively, and the segment skip regions ((1) in fig. 10 a) were radial regions having a radius of 2mm to 7 mm.

The radius of the electrode assemblies of examples 4-1 to 4-3 was 22mm, and the diameter of the core C was 4mm. In the height-variable region of the segment 61 (2) in fig. 10 a), the minimum height (h ₁ ) Is the same as 6mm, and has a maximum height (h _N ) Varying from 8mm to 10mm in 1mm increments. Therefore, in the electrode assemblies of examples 4-1 to 4-3, the widths of the height-variable regions of the segments ((2) in fig. 10 a) were 2mm, 3mm, and 4mm, respectively, and the segment skip regions ((1) in fig. 10 a) were radius regions having a radius of 2mm to 8 mm.

The radius of the electrode assemblies of examples 5-1 to 5-2 was 22mm, and the diameter of the core C was 4mm. In the height-variable region of the segment 61 (2) in fig. 10 a), the minimum height (h ₁ ) Is the same as 7mm, and has a maximum height (h _N ) Varying from 9mm to 10mm in 1mm increments. Therefore, in the electrode assemblies of examples 5-1 to 5-2, the widths of the height-variable regions of the segments ((2) in fig. 10 a) were 2mm and 3mm, respectively, and the segment skip regions ((1) in fig. 10 a) were radius regions having a radius of 2mm to 9 mm.

Fig. 10d is a graph showing the result of counting the number of overlapping layers of sections measured in the radial direction in the bent surface region F of the positive electrode formed on the upper portion of the electrode assembly according to examples 2-1 to 2-5, examples 3-1 to 3-4, examples 4-1 to 4-3, and examples 5-1 and 5-2. The inflection surface area of the negative electrode also showed about the same result.

In fig. 10d, graph (a) shows the result of counting the number of overlapping layers of the sections in the radial direction in the bending surface region F of examples 2-1 to 2-5, graph (b) shows the result of examples 3-1 to 3-4, graph C shows the result of examples 4-1 to 4-3, and graph (d) shows the result of examples 5-1 to 5-2.

Referring to fig. 10d, a zone b1 of uniform number of overlapping layers of segments is commonly present in all embodiments. The overlapping layer number uniform region b1 is a radial region of the flat region in the graph. When the minimum height (h ₁ ) At the same time, the length of the overlapping layer number uniform region b1 follows the maximum height (h _N ) Decreasing and increasing. Furthermore, when the maximum height of the section (h _N ) At the same time, the length of the overlapping layer number uniform region b1 follows the minimum height (h ₁ ) Decreasing and increasing. Meanwhile, in the overlapping layer number uniform region b1, the overlapping layer number of the sections follows the maximum height (h _N ) Increasing and increasing. Also in these embodiments, adjacent to the crossover number uniform zone b1, a crossover number reduction zone b2 occurs.

In these embodiments, the number of overlapping layers of the sections in the overlapping layer number uniform region b1 is 10 or more. Preferably, a region in which the number of overlapping layers of the segments is 10 or more may be set as a preferable welding target region.

In these embodiments, the overlapping layer number uniform region b1 starts from a radius point at which the height-variable region of the section ((2) in fig. 10 a) starts. In examples 2-1 to 2-5, the highly variable region of the segment ((2) in fig. 10 a) starts from 6mm and extends toward the periphery. In examples 3-1 to 3-4, the highly variable region of the segment ((2) in fig. 10 a) starts from 7mm and extends toward the periphery. In examples 4-3 to 4-3, the height variable region of the segment ((2) in fig. 10 a) starts from 8mm and extends toward the periphery. In examples 5-1 to 5-2, the height variable region of the segment ((2) in fig. 10 a) starts from 9mm and extends toward the periphery.

Table 5 below shows the results of calculating various parameters such as the ratio (e/f) of the length of the overlapping layer number uniform region to the length from the radius point (6 mm, 7mm, 8mm, 9 mm) of the overlapping layer number uniform region to the outermost point (22 mm) of the electrode assembly, the ratio (d/f) of the length of the height variable region ((2)) to the length from the radius point (6 mm, 7mm, 8mm, 9 mm) of the overlapping layer number uniform region to the outermost point (22 mm) of the electrode assembly, and the like for examples 2-1 to 2-5, examples 3-1 to 3-4, examples 4-1 to 4-3, and examples 5-1 to 5-2.

TABLE 5

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See examples 2-5, 3-4, 4-3 and 5-2 of Table 5 and FIGS. 10a and 10d, maximum height (h) of a zone in the zone's height variable region ((2)) _N ) Identical to 10mm, but the minimum height of the segments (h ₁ ) To 4mm, 5mm, 6mm and 7mm in 1mm increments, and the length of the height variable region ((2)) is reduced to 6mm, 5mm, 4mm, 3mm in 1mm decrements. Of the four examples, the ratio (e/f) of the overlapping layer number uniformity region was the largest in examples 2-5, which was 69%, and the smallest in example 5-2, which was 38%, and the overlapping layer number of the overlapping layer number uniformity region was the same in all examples. According to the results shown in Table 5, when the maximum height (h _N ) The minimum height (h ₁ ) When decreasing, it is understood that the width of the overlapping layer number uniform region increases proportionally with the increase in the width of the height-variable region ((2)) of the segment. The reason is that the minimum length (h ₁ ) Smaller, the radius point at which the segments start is closer to the core, such that the area of the stack of segments extends toward the core.

Referring to table 5, it can be found that the number of overlapping layers of the segments is 16 to 26, the ratio (d/f) of the highly variable regions ((2)) of the segments is 13% to 38%, and the ratio (e/f) of the overlapping layer number uniform regions is 31% to 69%. Further, the ratio (c/(b-a)) of the segment skip region ((1)) to the radius (b-a) (excluding the core) of the electrode assembly is 20% to 35%. Further, the ratio of the length of the electrode region corresponding to the segment skip region ((1)) 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 region ((2)) 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 region ((3)) to the total length of the electrode is 62% to 81%.

In the cylindrical batteries with form factors of 1865 and 2170, the radius of the electrode assembly is approximately 9mm to 10mm. Therefore, the radial length of the segment region (f) cannot be ensured at a level of 13mm to 16mm as in the embodiment, and the length of the segment skip region (c, (1)) cannot be ensured at a level of 4mm to 7mm, while the length of the overlapping layer number uniform region (e) in which the number of overlapping layers of the segment is 10 or more is ensured at a level of 5mm to 11 mm. This is because, in a conventional cylindrical battery, when the radius of the core is designed to be 2mm (as in these embodiments), the radial area in which the segments can be provided is approximately only 7mm to 8mm. Further, in the conventional cylindrical battery, the length of the electrode in the winding direction is at a level of 600mm to 980 mm. This short electrode length is only about 15% to 24% of the electrode length used in these examples (3948 mm positive electrode and 4045mm negative electrode). Therefore, the numerical ranges of the parameters h, i, and j cannot be easily derived from the design specifications of the conventional cylindrical battery.

Next, when the minimum height (h ₁ ) And maximum height (h) _N ) When the same in the height-variable region ((2)) of the segments, how the number of overlapping layers of the segments varies in the radial direction of the inflection surface region F according to the radius of the core C of the electrode assembly.

The radius of the electrode assemblies of examples 6-1 to 6-6 was 22mm, and the radius of the core C was 4mm. In the height-variable region of the segment 61 ((2)), the minimum height of the segment (h) ₁ ) Is the same as 3mm, and the maximum height of the segment (h _N ) Varying from 5mm to 10mm in 1mm increments. Thus, in the electrode assemblies of examples 6-1 to 6-6, the widths of the height-variable regions ((2)) of the segments were 2mm, 3mm, 4mm, 5mm, 6mm and 7mm, respectively, and the segment skip regions ((1)) were radial regions having a radius of 4mm to 7 mm.

Examples 7-1 to 7The radius of the electrode assembly of 6 is 22mm and the radius of the core C is 2mm. In the height-variable region ((2)) of the section 61, the minimum height (h ₁ ) Is the same as 3mm, and the maximum height of the segment (h _N ) Varying from 5mm to 10mm in 1mm increments. Thus, in the electrode assemblies of examples 7-1 to 7-6, the widths of the segment height-variable regions ((2)) were 2mm, 3mm, 4mm, 5mm, 6mm and 7mm, respectively, and the segment skip regions ((1)) were radial regions having a radius of 2mm to 5 mm.

Fig. 10e is a graph showing the result of counting the number of overlapped layers of the sections measured in the radial direction in the bent surface region F of the positive electrode formed on the upper portion of the electrode assembly of examples 6-1 to 6-6 and examples 7-1 to 7-6. The bent surface region of the negative electrode showed about the same result.

In fig. 10e, graph (a) shows the result of counting the number of overlapping layers of the sections measured in the radial direction in the inflection surface region F of examples 6-1 to 6-6, and graph (b) shows the result of examples 7-1 to 7-6.

Referring to fig. 10e, the overlapping layer number uniform region b1 of the sections is commonly present in all embodiments. The overlapping layer number uniform region b1 is a radial region of the flat region in the graph. When the minimum height (h ₁ ) At the same time, the radial length of the overlapping layer number uniform region b1 varies with the maximum height (h _N ) Decreasing and increasing. Meanwhile, in the overlapping layer number uniform region b1, the overlapping layer number of the sections follows the maximum height (h _N ) Increasing and increasing. In these embodiments, adjacent to the crossover number uniform zone b1, a crossover number reduction zone b2 occurs.

In these embodiments, the number of overlapping layers of the sections in the overlapping layer number uniform region b1 is 10 or more for all embodiments. Preferably, a region in which the number of overlapping layers of the segments is 10 or more may be set as a preferable welding target region.

In these embodiments, the overlapping layer number uniform region b1 starts from a radius point at which the highly variable region ((2)) of the section starts. In examples 6-1 to 6-6, the radius at the beginning of the zone height-variable region ((2)) was 7mm, and in examples 7-1 to 7-6, the radius at the beginning of the zone height-variable region ((2)) was 5mm.

Table 6 below shows the results of calculating various parameters including the ratio (e/f) of the length of the overlapping layer number uniform region to the length from the radius point (7 mm, 5 mm) starting from the overlapping layer number uniform region to the outermost point (22 mm) of the electrode assembly, the ratio (d/f) of the length of the height variable region ((2)) to the length from the radius point (7 mm, 5 mm) starting from the overlapping layer number uniform region to the outermost point (22 mm) of the electrode assembly, and the like for examples 6-1 to 6-6 and examples 7-1 to 7-6 and the like.

TABLE 6

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See examples 6-6 and 7-6 of Table 6 and FIG. 10a, the minimum height (h) of the zone in the zone's height variable zone ((2)) ₁ ) And maximum height (h) _N ) Identical to 3mm and 10mm respectively. However, in examples 6-6, the radius of the core was 2mm greater than in examples 7-6. Therefore, in examples 6 to 6, the number of overlapping layers of the uniform region (e) and the section region (f) was smaller by 2mm as compared with examples 7 to 6, and the number of overlapping layers of the sections in the uniform region of the number of overlapping layers was the same. These results are derived from the difference in core radius. From the results shown in table 6, it can be understood that when the widths of the height-variable regions ((2)) of the sections are the same, the ratio (d/f) of the height-variable regions ((2)) decreases and the ratio (e/f) of the number of overlapping layers of the uniform regions increases because the radius (a) of the core is smaller. Referring to table 6, it can be found that the number of overlapping layers of the segments is 13 to 26, the ratio (d/f) of the highly variable regions ((2)) of the segments is 12% to 47%, and the ratio (e/f) of the overlapping layer number uniform regions is 40% to 76%. Further, the ratio (c/(b-a)) of the segment skip region ((1)) to the radius (b-a) (excluding the core) of the electrode assembly is 15% to 17%. In addition, the length of the electrode region and the electrode corresponding to the segment skip region ((1)) The ratio of the total length is 6%, the ratio of the length of the electrode region corresponding to the height-variable region ((2)) 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 region ((3)) to the total length of the electrode is 59% to 83%.

For cylindrical cells with form factors of 1865 and 2170, the radius of the electrode assembly is approximately 9mm to 10mm. Therefore, the radial length of the section area (f) cannot be ensured at a level of 15mm to 17mm, and the length of the section skip area ((1)) cannot be ensured at a level of about 3mm, while the length of the overlapping layer number uniform area (e) in which the number of overlapping layers of the section is 10 or more is ensured at a level of 6mm to 13mm as in these embodiments. This is because, in a conventional cylindrical battery, when the radius of the core is designed to be 2mm to 4mm (as in these embodiments), the radial area in which the segments can be provided is approximately only 5mm to 8mm. Further, in the conventional cylindrical battery, the length of the electrode in the winding direction is at a level of 600mm to 980 mm. This short electrode length is only about 15% to 24% of the electrode length used in these examples (3948 mm positive electrode and 4045mm negative electrode). Therefore, the numerical ranges of the parameters h, i, and j cannot be easily derived from the design specifications of the conventional cylindrical battery.

Considering the data in tables 4 to 6 in combination, the number of overlapping layers of the sections in the area where the number of overlapping layers of the sections is uniform may be 11 to 26. Furthermore, the ratio (d/f) of the highly variable region ((2)) of the segment may be 6% to 47%. Further, the ratio (e/f) of the overlapping layer number uniformity region may be 31% to 82%. Further, the ratio (c/(b-a)) of the length of the segment skip region ((1)) to the radius of the electrode assembly excluding the core may be 15% to 35%. Further, the ratio of the length of the electrode region corresponding to the segment skip region ((1)) to the total length of the electrode (length in the winding direction) may be 6% to 20%. Furthermore, the ratio of the length of the electrode region corresponding to the height-variable region ((2)) of the segment to the total length of the electrode may be 3% to 32%. Furthermore, the ratio of the length of the electrode region corresponding to the highly uniform region ((3)) of the segment to the total length of the electrode may be 59% to 87%.

At the same time, described by means of tables 4 to 6The parameters may vary depending on design factors including: radius of core (a); radius (b) of the electrode assembly; minimum height (h) in height variable zone of zone ((2)) ₁ ) And maximum height (h) _N ) The method comprises the steps of carrying out a first treatment on the surface of the Height variation (Δh) per 1mm radius increase segment; the thicknesses of the positive electrode, the negative electrode, and the separator, and the like.

Thus, in the area where the number of overlapping layers of the sections is uniform, the number of overlapping layers of the sections can be expanded to 10 to 35. The ratio (d/f) of the highly variable regions ((2)) of the segments can be extended to 1% to 50%. In addition, the ratio (e/f) of the overlapping layer number uniformity region may be extended to 30% to 85%. Further, the ratio (c/(b-a)) of the length of the segment skip region ((1)) to the radius of the electrode assembly excluding the core may be extended to 10% to 40%. Further, the ratio of the length of the electrode region corresponding to the segment skip region ((1)) to the total length of the electrode (length in the winding direction) may be extended to 1% to 30%. Furthermore, the ratio of the length of the electrode region corresponding to the height-variable region ((2)) of the segment to the total length of the electrode may be extended to 1% to 40%. Furthermore, the ratio of the length of the electrode region corresponding to the highly uniform region ((3)) of the segment to the total length of the electrode may be extended to 50% to 90%. In the above embodiment, the maximum heights (h) of the sections in the height-variable region ((2)) and the height-uniform region ((3)) _N ) The height index "N" in (2) to (8). For example, referring to Table 4, examples 1-1 and 1-7 have a height index "N" of 2 and 8, respectively. However, the height index "N" may vary according to the height variation (Δh) of the segments in the radial direction of the electrode assembly. When the radial length of the height-variable zone ((2)) is fixed, as the height variation (Δh) of the segment decreases, the height index "N" correspondingly increases, and vice versa. Preferably, the height index "N" can be extended to a range of 2 to 20, and optionally further extended to a range of 2 to 30.

In the inflection surface regions F formed at the top and bottom of the electrode assembly, the overlapping layer number uniform region may serve as a welding target region of the current collector.

Preferably, the welding region of the current collector overlaps at least 50% of the overlapping layer number uniform region in the radial direction of the electrode assembly. Here, a higher overlapping ratio is more preferable.

Preferably, a remaining region of the welding region of the current collector, which does not overlap the overlapping layer number uniform region, may overlap the overlapping layer number reduction region adjacent to the overlapping layer number uniform region in the radial direction.

More preferably, the remaining region of the welding region of the current collector, which does not overlap the overlapping layer number uniform region, may overlap the region of the overlapping layer number reduced region, which has the overlapping layer number of 10 or more.

If the current collector is welded to the region where the number of the stacked layers of the segments is 10 or more, it is preferable in terms of welding strength and in terms of preventing damage to the separator or the active material layer during welding. In particular, it is useful when welding current collectors using high power lasers having high penetration characteristics.

If the overlapping layer number uniform region in which the sections of 10 or more are stacked is welded to the current collector with laser, even if the laser output is increased to improve welding quality, the overlapping layer number uniform region absorbs most of laser energy to form a weld bead, and thus the separator and the active material layer under the bending surface region F can be prevented from being damaged by the laser.

In the laser-irradiated region, the number of overlapping layers of the segments is 10 or more, and therefore a weld bead having a sufficient approximate volume and thickness is formed. Therefore, the welding strength can be sufficiently ensured, and the resistance of the welding interface can be reduced to a level suitable for rapid charging.

When welding the current collector, the laser output may be determined by the desired weld strength between the inflection surface region F and the current collector. The weld strength increases in proportion to the number of overlapping layers of the segments. This is because the volume of the weld bead formed by the laser increases as the number of overlapping layers increases. When the material of the current collector and the material of the segments are melted together, a weld bead is formed. Thus, if the volume of the weld bead is large, the current collector and the inflection surface region are more firmly coupled and the contact resistance of the welding interface is reduced.

Preferably, the welding strength may be 2kgf/cm ² The above is more preferably 4kgf/cm ² The above. Maximum welding strengthMay depend on the power of the laser welding apparatus. As an example, the welding strength may be preferably set to 8kgf/cm ² Hereinafter, more preferably 6kgf/cm ² The present invention is not limited to the following.

If the welding strength satisfies the above numerical range, physical properties of the welding interface are not deteriorated even if strong vibration is applied to the electrode assembly in the winding axis direction and/or the radial direction, and the resistance of the welding interface may be reduced due to a sufficiently large volume of the weld bead.

The laser power satisfying the welding strength condition varies according to the laser apparatus and may be appropriately adjusted in the range of 250W to 320W or 40% to 100% of the maximum laser power specification provided by the corresponding apparatus.

The welding strength may be defined as a tensile force per unit area (kgf/cm) of the current collector when the current collector starts to separate from the inflection surface region F ² ). Specifically, after the current collector is completely welded, a tensile force may be applied to the current collector, but the magnitude of the tensile force may be gradually increased. If the pulling force exceeds the threshold, the segment begins to separate from the weld interface. At this time, a value obtained by dividing the tensile force applied to the current collector by the area of the current collector corresponds to the welding strength.

In the inflection surface region F, the segments are stacked in a plurality of layers, and according to the above embodiment, the number of overlapping layers of the segments can be increased from a minimum of 10 sheets to a maximum of 35 sheets.

The thickness of the positive electrode current collector (foil) constituting the non-coating portion 43 may be in the range of 10 μm to 25 μm, and the thickness of the negative electrode current collector (foil) constituting the non-coating portion 43 may be in the range of 5 μm to 20 μm. Thus, the inflection surface region F of the positive electrode may include a region in which the total overlapping thickness of the segments is 100 μm to 875 μm. Further, the inflection surface region F of the anode may include a region in which the total overlapping thickness of the segments is 50 μm to 700 μm.

Fig. 10F is a top plan view illustrating an electrode assembly in which an overlapping layer number uniform region b1 and an overlapping layer number reduced region b2 are depicted in a inflection surface region F of sections 61, 61', according to one embodiment of the present disclosure.

Referring to fig. 10F, the region between two circles indicated by the thick solid line corresponds to the folded surface region F of the segment, and the region between two circles indicated by the chain line corresponds to the overlapping layer number uniform region b1 in which the overlapping layer number of the segment is 10 or more, and the outer region of the overlapping layer number uniform region b1 corresponds to the overlapping layer number reduced region b2.

In one embodiment, if the current collector (P _c ) Welded to the inflection surface region F, the heat is transferred to the current collector (P _c ) Form a welding pattern (W) on the surface of _p ). Welding pattern (W) _p ) May be a line pattern or a dot matrix pattern. Welding pattern (W) _p ) Corresponds to the welding region and may overlap the overlapping layer number uniform region b1 of the section by 50% or more in the radial direction. Thus, a part (W _p ) May be included in the overlapping layer number uniform region b1, and the remaining part (W _p ) May be included in the overlap number amount reduction region b2 outside the overlap number amount uniform region b 1. Of course, the whole welding pattern (W _p ) May overlap with the overlapping layer number uniform region b1 to maximize the welding strength and reduce the resistance in the welding region.

The area of the inflection surface region F may be defined as the sum of the area of the overlapping layer number uniform region b1 of the sections and the area of the overlapping layer number reduced region b 2. Since the ratio (e/F) of the overlapping layer number uniform region b1 is 30% to 85%, preferably 31% to 82%, the ratio of the area of the overlapping layer number uniform region b1 to the area of the inflection surface region F can be 9% (30 ² /100 ² ) Up to 72% (85) ² /100 ² ) Preferably 10% (31) ² /100 ² ) Up to 67% (82) ² /100 ² )。

Preferably, the current collector (P _c ) The edges of the portion contacting the inflection surface region F may cover the ends of the sections 61, 61 of the last convolution of the highly uniform region ((3)) that are inflection toward the core C. In this case, due to the welding pattern (W _p ) Formed in sections 61, 61' as a current collector (P _c ) In the pressed state, therefore, the current collector (P _c ) Is firmly connected with the bending surface area F. Accordingly, the sections 61, 61 'stacked in the winding axis direction are closely adhered to each other, thereby reducing the resistance at the welding interface and preventing the sections 61, 61' from lifting.

Meanwhile, the bending direction of the sections may be opposite to that described above. That is, the segments may be bent from the core toward the outer periphery. In this case, the pattern in which the height of the segments varies in the winding direction (X-axis direction) may be opposite to the pattern of the foregoing embodiment (modification). For example, the height of the segments may gradually decrease from the core towards the periphery. Furthermore, the structure applied to the first portion B1 and the structure applied to the second portion B3 may be exchanged with each other. Preferably, the height variation pattern of the segments may be designed such that the heights of the segments gradually decrease from the core side to the outer circumference side, but when the segments closest to the outer circumference of the electrode assembly are bent toward the outer circumference, the ends of the segments are not exposed to the outside of the outer circumference of the electrode assembly.

The electrode structure of the above embodiment (modification) may be applied to at least one of the first electrode and the second electrode having different polarities included in a jelly-roll type electrode assembly or other types of electrode assemblies known in the art. Further, when the electrode structure of the above embodiment (modification) is applied to either one of the first electrode and the second electrode, a conventional electrode structure may be applied to the other. Further, the electrode structures applied to the first electrode and the second electrode may not be the same but different from each other.

For example, when the first electrode and the second electrode are a positive electrode and a negative electrode, respectively, any of the above embodiments (modifications) is applied to the first electrode, and a conventional electrode structure may be applied to the second electrode (see fig. 1).

As another example, when the first electrode and the second electrode are a positive electrode and a negative electrode, respectively, any of the above embodiments (modifications) may be selectively applied to the first electrode, and any of the above embodiments (modifications) may be selectively applied to the second electrode.

In the present disclosure, the positive electrode active material coated on the positive electrode and the negative electrode active material coated on the negative electrode may employ any active material known in the art without limitation.

In one embodiment, the positive electrode active material may include a material represented by the general formula A [ A ] _x M _y ]O _2+z The alkali metal compound represented (A comprises at least one of Li, na and K; M comprises at least one element selected from Ni, co, mn, ca, mg, al, ti, si, fe, mo, V, zr, zn, cu, al, mo, sc, zr, ru and Cr; x.gtoreq.0, 1.ltoreq.x+y.ltoreq.2, -0.1.ltoreq.z.ltoreq.2; and the stoichiometric coefficients of x, y and z are selected so as to maintain the electroneutrality of the compound).

In another embodiment, the positive electrode active material may be an alkali metal compound xLiM disclosed in US 6,677,082, US 6,680,143, or the like ¹ O ₂ -(1-x)Li ₂ M ² O ₃ (M ¹ Comprising at least one element having an average oxidation state of 3; m is M ² Comprising at least one element having an average oxidation state of 4; and 0.ltoreq.x.ltoreq.1).

In yet another embodiment, the positive electrode active material may be a material represented by the general formula Li _a M ¹ _x Fe _1-x M ² _y P _1-y M ³ _z O _4-z (M ¹ Comprises at least one element selected from Ti, si, mn, co, fe, V, cr, mo, ni, nd, al, mg and Al; m is M ² Comprising 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 is M ³ Comprising a halogen element optionally comprising F; a is more than or equal to 0 and less than or equal to 2, x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, and z is more than or equal to 0 and less than or equal to 1; the stoichiometric coefficient of a, x, y, z is selected to maintain the charge neutrality of the compound) or Li ₃ M ₂ (PO ₄ ) ₃ (M includes at least one element selected from Ti, si, mn, fe, co, V, cr, mo, ni, al, mg and Al).

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

In one embodiment, the anode active material may employ a carbon material, lithium metal or lithium metal compound, silicon or silicon compound, tin or tin compound, or the like. Metal oxides having a potential of less than 2V (e.g. TiO ₂ And SnO ₂ ) Can also be used as a negative electrode active material. As the carbon material, low crystalline carbon, high crystalline carbon, and the like can be used.

The separator may employ a porous polymer film, such as 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, or the like, or a laminate thereof. As another example, the separator may employ a general porous non-woven fabric, for example, a non-woven fabric made of glass fiber having a high melting point, polyethylene terephthalate fiber, or the like.

A coating layer of inorganic particles may be included in at least one surface of the separator. It is also possible that the separator itself is made of a coating layer of inorganic particles. The particles in the coating layer may be coupled with a binder such that inter-particulate volumes exist between adjacent particles.

The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. In one non-limiting embodiment, the inorganic particles may include at least one material selected from the group consisting of: pb (Zr, ti) O ₃ (PZT)、Pb _1-x La _x Zr _1-y Ti _y O ₃ (PLZT)、PB(Mg ₃ Nb _2/3 )O ₃ -PbTiO ₃ (PMN-PT)、BaTiO ₃ 、HfO ₂ 、SrTiO ₃ 、TiO ₂ 、Al ₂ O ₃ 、ZrO ₂ 、SnO ₂ 、CeO ₂ MgO, caO, znO and Y ₂ O ₃ 。

Hereinafter, the structure of the electrode assembly according to one embodiment of the present disclosure will be described in detail.

Fig. 11 is a sectional view showing a jellyroll-type electrode assembly 80 in which the first electrode (positive electrode) and the second electrode (negative electrode) are applied to the electrode 40 of the first embodiment, as taken along the Y-axis direction (winding axis direction).

The electrode assembly 80 may be manufactured by the winding method described with reference to fig. 2. For convenience of description, the protruding structures of the first and second uncoated portions 43a and 43b extending out of the separator are shown in detail, and the winding structures of the first and second electrodes and the separator are not shown. The first uncoated portion 43a protruding upward extends from the first electrode, and the second uncoated portion 43b protruding downward extends from the second electrode.

The pattern of the height variation of the first and second uncoated portions 43a and 43b is schematically shown. That is, the height of the uncoated portion may be irregularly changed according to the position of the cut profile. For example, at a section cutting the sides of the trapezoid sections 61, 61 'or the cutting groove 63, the height of the uncoated portion in the section is lower than the height H of the sections 61, 61'. Therefore, it should be understood that the height of the non-coating portion depicted in the drawings showing the cross-section of the electrode assembly corresponds to an average value of the heights (H in fig. 7b and 8 b) of the non-coating portion included in each convolution.

Referring to fig. 11, the first non-coating portion 43a includes a first portion B1 adjacent to the core of the electrode assembly 80, a second portion B3 adjacent to the outer circumference of the electrode assembly 80, and a third portion B2 interposed between the first portion B1 and the second portion B3.

The height (length in the Y-axis direction) of the second portion B3 is relatively smaller than the height of the third portion B2. Therefore, it is possible to prevent an internal short circuit from occurring due to the bead portion and the second portion B3 contacting each other when the bead portion of the battery case is pressed near the second portion B3.

The second uncoated portion 43b has the same structure as the first uncoated portion 43 a. In one modification, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (modifications).

The end portions 81 of the first and second uncoated portions 43a and 43b may be bent in the radial direction of the electrode assembly 80, for example, from the outer circumference toward the core. At this time, the second portion B3 may be substantially not bent.

Fig. 12 is a cross-sectional view showing a jellyroll-type electrode assembly 90 in which the electrode 45 of the second embodiment is applied to the first electrode (positive electrode) and the second electrode (negative electrode) along the Y-axis direction (winding axis direction).

Referring to fig. 12, the first non-coating portion 43a includes a first portion B1 adjacent to the core of the electrode assembly 90, a second portion B3 adjacent to the outer circumference of the electrode assembly 90, and a third portion B2 interposed between the first portion B1 and the second portion B3.

The height of the second portion B3 is relatively smaller than the height of the third portion B2, and gradually or stepwise decreases from the core to the outer periphery. Therefore, it is possible to prevent an internal short circuit from occurring due to the bead portion and the second portion B3 contacting each other when the bead portion of the battery case is pressed near the second portion B3.

The end portions 91 of the first and second uncoated portions 43a and 43b may be bent in the radial direction of the electrode assembly 90, for example, from the outer circumference to the core. At this time, the outermost portion 92 of the second portion B3 may be substantially unbent.

Fig. 13 is a sectional view showing a jellyroll-type electrode assembly 100 in which the electrodes 50, 60, 70 of the third to fifth embodiments (modifications thereof) are applied to the first electrode (positive electrode) and the second electrode (negative electrode) along the Y-axis direction (winding axis direction).

Referring to fig. 13, the first non-coating portion 43a includes a first portion B1 adjacent to the core of the electrode assembly 100, a second portion B3 adjacent to the outer circumference of the electrode assembly 100, and a third portion B2 interposed between the first portion B1 and the second portion B3.

The height of the first portion B1 is relatively smaller than the height of the third portion B2. Further, the folded length of the uncoated portion 43a located at the innermost side of the third portion B2 is equal to or smaller than the radial length (R) of the first portion B1. The bending length (H) corresponds to a distance from the bending point of the uncoated portion 43a to the top of the uncoated portion 43 a. In one variation, the bend length (H) may be less than the sum of the radial length (R) of the first portion B1 and 10% of the radius of the core 102.

Therefore, even if the third portion B2 is bent, the core 102 of the electrode assembly 100 is opened to the outside by 90% or more of the diameter of the core 102. 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 difficult and the electrolyte injection efficiency is improved. Further, by inserting a welding jig through the core 102, a welding process can be easily performed between the current collector of the negative electrode (or positive electrode) and the battery case (or terminal).

The height of the second portion B3 is relatively smaller than the height of the third portion B2. Therefore, when the beading portion of the battery case is pressed near the second portion B3, the beading portion and the second portion B3 can be prevented from contacting each other to cause an internal short circuit.

In a variant, the height of the second portion B3 may be gradually or stepwise reduced, unlike that shown in fig. 13. Further, in fig. 13, although the height of the third portion B2 is partially the same in the circumferential direction, the height of the third portion B2 may gradually or stepwise increase from the boundary between the first portion B1 and the third portion B2 to the boundary between the third portion B2 and the second portion B3. When the third portion B2 is divided into a plurality of sections, the region in which the height of the uncoated portion 43a varies corresponds to the height-variable region of the section ((2) in fig. 10 a).

The end portions 101 of the first and second uncoated portions 43a and 43b may be bent in the radial direction of the electrode assembly 100, for example, from the outer circumference to the core. At this time, the first portion B1 and the second portion B3 are not substantially bent.

When the third portion B2 includes a plurality of sections, the bending stress can be relieved to prevent the uncoated portion 43a near the bending point from being torn or deformed abnormally. Furthermore, when the width and/or height of the segments and/or the separation pitch are adjusted according to the numerical ranges of the above embodiments, the segments are folded toward the core and overlapped in the layers to sufficiently secure the welding strength, and no empty holes (gaps) are formed in the folded surface region.

Fig. 14 shows a cross-sectional view of an electrode assembly 110 according to still another embodiment of the present disclosure, taken along the Y-axis direction (winding axis direction).

Referring to fig. 14, the electrode assembly 110 is substantially the same as the electrode assembly 100 of fig. 13, except that the height of the second portion B3 is substantially the same as the outermost height of the third portion B2.

The second portion B3 may include a plurality of sections. The configuration of the plurality of sections is substantially the same as that described in the fourth and fifth embodiments (modifications) regarding the electrodes.

In the electrode assembly 110, the height of the first portion B1 is relatively smaller than the height of the third portion B2. Further, the folded length (H) of the uncoated portion located at the innermost side of the third portion B2 is equal to or smaller than the radial length (R) of the first portion B1. Preferably, the first portion B1 may be a section skip zone having no section ((1) in fig. 10 a). In one variation, the bend length (H) may be less than the sum of the radial length (R) of the first portion B1 and 10% of the radius of the core 102.

Therefore, even if the third portion B2 is bent, the core 112 of the electrode assembly 110 is opened to the outside by at least 90% or more of the diameter of the core 112. If the core 112 is not blocked, there is no difficulty in the electrolyte injection process, and the electrolyte injection efficiency is improved. Further, by inserting a welding jig through the core 112, a welding process can be easily performed between the current collector of the negative electrode (or positive electrode) and the battery case (or terminal).

In a modification, the structure in which the height of the third portion B2 gradually or stepwise increases from the core toward the outer periphery may extend to the second portion B3. In this case, the height of the non-coating portion 43a may be gradually or stepwise increased from the boundary between the first and third portions B1 and B2 to the outermost surface of the electrode assembly 110.

The end portions 111 of the first and second non-coating portions 43a and 43b may be bent in the radial direction of the electrode assembly 110, for example, from the outer circumference toward the core. At this time, the first portion B1 is not substantially bent.

When the third portion B2 and the second portion B3 include a plurality of sections, the bending stress can be relieved to prevent the uncoated portions 43a, 43B near the bending point from being torn or deformed abnormally. Furthermore, when the width and/or height of the segments and/or the separation pitch are adjusted according to the numerical ranges of the above embodiments, the segments are folded toward the core and overlapped in the layers to sufficiently secure the welding strength, and no empty holes (gaps) are formed in the folded surface region.

Fig. 15 shows a cross-sectional view of an electrode assembly 120 according to still another embodiment of the present disclosure, taken along the Y-axis direction (winding axis direction).

Referring to fig. 15, the electrode assembly 120 is substantially the same as the electrode assembly 100 of fig. 13, except that the height of the third portion B2 has a pattern that gradually or stepwise increases and then decreases. The radial region in which the height of the third portion B2 varies may be regarded as a height-variable region of the segment ((2) in fig. 10 a). Even in this case, the height-variable region of the segment may be designed such that the overlapping layer number uniformity region in which the number of overlapping layers of the segment is 10 or more appears within the above-described preferred numerical range in the folded surface region F formed by folding the third portion B2.

This variation in the height of the third portion B2 may be implemented by using a stepped pattern (see fig. 6) or adjusting the height of the sections included in the third portion B2 (see fig. 7a or 8 a).

In the electrode assembly 120, the height of the first portion B1 is relatively smaller than the height of the third portion B2. Further, the folded length (H) of the uncoated portion located at the innermost side of the third portion B2 is equal to or smaller than the radial length (R) of the first portion B1. The area corresponding to the first portion B1 corresponds to a section skip area having no section ((1) in fig. 10 a). In one variation, the bend length (H) may be less than the sum of the radial length (R) of the first portion B1 and 10% of the radius of the core 102.

Therefore, even if the third portion B2 is bent toward the core, the core 122 of the electrode assembly 120 is opened to the outside by at least 90% or more of its diameter. If the core 122 is not blocked, there is no difficulty in the electrolyte injection process, and the electrolyte injection efficiency is improved. Further, by inserting a welding jig through the core 122, a welding process can be easily performed between the current collector of the negative electrode (or positive electrode) and the battery case (or terminal).

Furthermore, the height of the second portion B3 is relatively smaller than that of the third portion B2, and preferably, a section may not be formed in the second portion B3. Therefore, it is possible to prevent an internal short circuit from occurring due to the bead portion and the second portion B3 contacting each other when the bead portion of the battery case is pressed near the second portion B3. In a variant, the height of the second portion B3 may decrease gradually or stepwise towards the periphery.

The end portions 121 of the first and second non-coating portions 43a and 43b may be bent from the outer circumference of the electrode assembly 120 to the core. At this time, the first portion B1 and the second portion B3 are not substantially bent.

When the third portion B2 includes a plurality of sections, the bending stress can be relieved to prevent the uncoated portions 43a, 43B from being torn or deformed abnormally. Furthermore, when the width and/or height of the segments and/or the separation pitch are adjusted according to the numerical ranges of the above embodiments, the segments are folded toward the core and overlapped in the layers to sufficiently secure the welding strength, and no empty holes (gaps) are formed in the folded surface region.

Fig. 16 shows a cross-sectional view of an electrode assembly 130 according to still another embodiment of the present disclosure, taken along the Y-axis direction (winding axis direction).

Referring to fig. 16, the electrode assembly 130 is substantially the same as the electrode assembly 120 of fig. 15, except that the height of the second portion B3 has a pattern gradually or stepwise decreasing from the boundary point of the second portion B3 and the third portion B2 toward the outermost surface of the electrode assembly 130.

This variation in the height of the second portion B3 may be implemented by extending the step pattern (see fig. 6) included in the third portion B2 to the second portion B3 while gradually or stepwise decreasing the height of the pattern toward the outer circumference. Further, in another modification, the height change of the second portion B3 may be implemented by extending the section structure of the third portion B2 to the second portion B3 while gradually or stepwise decreasing the height of the section toward the outer periphery.

In the electrode assembly 130, the height of the first portion B1 is relatively smaller than the height of the third portion B2. Further, in the third portion B2, the bending length (H) of the innermost uncoated portion is equal to or smaller than the radial length (R) of the first portion B1. The first portion B1 corresponds to a section skip zone having no section ((1) in fig. 10 a). In one variation, the bend length (H) may be less than the sum of the radial length (R) of the first portion B1 and 10% of the radius of the core 102.

Therefore, even if the third portion B2 is bent toward the core, the core 132 of the electrode assembly 130 is opened to the outside by at least 90% or more of its diameter. If the core 132 is not blocked, there is no difficulty in the electrolyte injection process, and the electrolyte injection efficiency is improved. Further, by inserting a welding jig through the core 132, a welding process can be easily performed between the current collector of the negative electrode (or positive electrode) and the battery case (or terminal).

The end portions 131 of the first and second non-coating portions 43a and 43b may be bent from the outer circumference of the electrode assembly 130 to the core. At this time, the first portion B1 is not substantially bent.

Meanwhile, in the foregoing embodiment (modification), the end portions of the first and second uncoated portions 43a and 43b may be bent from the core toward the outer periphery. In this case, the second portion B3 is preferably designed as a section skip region having no section ((1) in fig. 10 a) and is not bent toward the outer circumference. Further, the width of the second portion B3 in the radial direction may be equal to or greater than the length of the outermost uncoated portion (or section) bend of the third portion B2. Only when the outermost uncoated portion (or section) of the third portion B2 is bent toward the outer circumference, the end of the bent portion does not protrude beyond the outer circumference of the electrode assembly toward the inner surface of the battery case. Furthermore, the pattern of variation of the segment structure may be reversed from the previous embodiment (modification). For example, the height of the segments may increase gradually or gradually from the core towards the periphery. That is, by sequentially arranging the segment skip region (fig. 10a (1)), the height variable region of the segment (fig. 10a (2)) and the height uniform region of the segment (fig. 10a (3)) from the outer periphery of the electrode assembly to the core, the overlapping layer number uniform region in which the number of overlapping layers of the segment is 10 or more may occur within an ideal numerical range in the inflection surface region.

Various electrode assembly structures according to one embodiment of the present disclosure may be applied to a cylindrical battery.

Preferably, the cylindrical battery may be, for example, a cylindrical battery having a shape factor ratio (defined as the diameter of the cylindrical battery divided by the height, i.e., the ratio of height (H) to diameter (Φ)) of greater than about 0.4. Here, the form factor refers to a value indicating the diameter and height of the cylindrical battery.

Preferably, the cylindrical battery may have a diameter of 40mm to 50mm and a height of 60mm to 130 mm. The form factor of a cylindrical battery according to one embodiment of the present disclosure may be, for example, 46110, 4875, 48110, 4880, or 4680. Among the values representing the form factors, the first two numbers indicate the diameter of the battery, and the remaining numbers indicate the height of the battery.

When the electrode assembly having the non-joint structure is applied to a cylindrical battery having a shape factor ratio of more than 0.4, stress applied in a radial direction when the uncoated portion is bent is large, so that the uncoated portion may be easily torn. Further, when welding the current collector to the folded surface region of the uncoated portion, it is necessary to sufficiently increase the number of overlapped layers of the uncoated portion on the folded surface region in order to sufficiently secure the welding strength and reduce the resistance. This requirement can be achieved by means of an electrode and an electrode assembly according to an embodiment (variant) of the present disclosure.

A battery according to one embodiment of the present disclosure may be a cylindrical battery having an approximately cylindrical shape with a diameter of approximately 46mm, a height of approximately 110mm, and a form factor ratio of 0.418.

The battery according to another embodiment may be a cylindrical battery having a substantially cylindrical shape with a diameter of about 48mm and a height of about 75mm, and a shape factor ratio of 0.640.

The battery according to still another embodiment may be a cylindrical battery having an approximately cylindrical shape, which has a diameter of approximately 48mm, a height of approximately 110mm, and a shape factor ratio of 0.436.

The battery according to still another embodiment may be a cylindrical battery having an approximately cylindrical shape, which has a diameter of approximately 48mm, a height of approximately 80mm, and a shape factor ratio of 0.600.

The battery according to still another embodiment may be a cylindrical battery having an approximately cylindrical shape, which has a diameter of approximately 46mm, a height of approximately 80mm, and a shape factor ratio of 0.575.

Batteries having a shape factor ratio of about 0.4 or less have conventionally been used. That is, for example, 1865 battery, 2170 battery, and the like are conventionally used. 1865 cells have a diameter of approximately 18mm, a height of approximately 65mm, and a form factor ratio of 0.277. 2170 cells had a diameter of approximately 21mm, a height of approximately 70mm and a form factor ratio of 0.300.

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

Fig. 17 illustrates a cross-sectional view of a cylindrical battery 140 according to an embodiment of the present disclosure, taken along the Y-axis direction.

Referring to fig. 17, a cylindrical battery 140 according to one embodiment of the present disclosure includes an electrode assembly 141 having a first electrode, a separator, and a second electrode, a battery case 142 for accommodating the electrode assembly 141, and a sealing body 143 for sealing an open end of the battery case 142.

The battery case 142 is a cylindrical container having an opening at the top. The battery case 142 is made of a conductive metal material such as aluminum, steel, or stainless steel. A nickel coating layer may be formed on the surface of the battery case 142. The battery case 142 accommodates the electrode assembly 141 in the inner space through the top opening, and also accommodates an electrolyte.

The electrolyte may be of a material such as A ⁺ B ^- Is a salt of the structure of (a). Here, A ⁺ Comprising alkali metal cations, e.g. Li ⁺ 、Na ⁺ Or K ⁺ Or a combination thereof. And B is ^- Comprising at least one anion selected from the group consisting of: f (F) ^- ；Cl ^- ；Br ^- ；I ^- ；NO ₃ ^- ；N(CN) ₂ ^- ；BF ₄ ^- ；ClO ₄ ^- ；AlO ₄ ^- ；AlCl ₄ ^- ；PF ₆ ^- ；SbF ₆ ^- ；AsF ₆ ^- ；BF ₂ C ₂ O ₄ ^- ；BC ₄ O ₈ ^- ；(CF ₃ ) ₂ PF ₄ ^- ；(CF ₃ ) ₃ PF ₃ ^- ；(CF ₃ ) ₄ PF ₂ ^- ；(CF ₃ ) ₅ PF ^- ；(CF ₃ ) ₆ P ^- ；CF ₃ SO ₃ ^- ；C ₄ F ₉ SO ₃ ^- ；CF ₃ CF ₂ SO ₃ ^- ；(CF ₃ SO ₂ ) ₂ N ^- ；(FSO ₂ ) ₂ N ^- ；CF ₃ CF ₂ (CF ₃ ) ₂ CO ^- ；(CF ₃ SO ₂ ) ₂ CH ^- ；(SF ₅ ) ₃ C ^- ；(CF ₃ SO ₂ ) ₃ C ^- ；CF ₃ (CF ₂ ) ₇ SO ₃ ^- ；CF ₃ CO ₂ ^- ；CH ₃ CO ₂ ^- ；SCN ^- (CF) ₃ CF ₂ SO ₂ ) ₂ N ^- 。

The electrolyte may also be dissolved in an organic solvent. The organic solvent may be Propylene Carbonate (PC), ethylene Carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), γ -butyrolactone, or a mixture thereof.

The electrode assembly 141 may have a jelly-roll shape, but the present invention is not limited thereto. As shown in fig. 2, the electrode assembly 141 may be manufactured by winding a laminate formed by sequentially laminating a lower separator, a first electrode, an upper separator, and a second electrode at least once based on a winding axis of the core C.

The first electrode and the second electrode have different polarities. That is, if one electrode has a positive polarity, the other electrode has a negative polarity. At least one of the first electrode and the second electrode may have an electrode structure according to the above embodiment (modification). Further, the other of the first electrode and the second electrode may have a conventional electrode structure or an electrode structure according to an embodiment (modification). The electrode pairs included in the electrode assembly 141 are not limited to one pair, but may also include two or more pairs.

The first uncoated portion 146a of the first electrode and the second uncoated portion 146b of the second electrode protrude from the upper and lower portions of the electrode assembly 141, respectively. The first electrode has the electrode structure of the first embodiment (modification). Therefore, in the first uncoated portion 146a, the height of the second portion B3 is smaller than that of the uncoated portion of the other region. The second portion B3 is spaced apart from the inner circumference of the battery case 142 (particularly, the beading portion 147) at a predetermined interval. Accordingly, the second portion B3 of the first electrode is not in contact with the battery case 142 electrically connected to the second electrode, thereby preventing an internal short circuit of the battery 140.

The second uncoated portion 146b of the second electrode may have the same structure as the first uncoated portion 146 a. In another modification, the second uncoated portion 146b may optionally have a structure of an uncoated portion of the electrode according to the embodiment (modification).

The sealing body 143 may include: a cap 143a having a plate shape; a first gasket 143b for providing air tightness and insulation between the cap 143a and the battery case 142; and a connection plate 143c electrically and mechanically coupled to the cap 143a.

The cap 143a is a member made of a conductive metal material, and covers the top opening of the battery case 142. The cap 143a is electrically connected to the uncoated portion 146a of the first electrode, and is electrically insulated from the battery case 142 by the first gasket 143 b. Accordingly, the cap 143a may serve as a first electrode terminal (e.g., a positive electrode) of the cylindrical battery 140.

The cap 143a is placed on the beading portion 147 formed on the battery case 142 and is fixed by means of the crimp portion 148. Between the cap 143a and the crimp 148, a first gasket 143b may be interposed to ensure the air tightness of the battery case 142 and the electrical insulation between the battery case 142 and the cap 143a. The cap 143a may have a protrusion 143d protruding upward from its center.

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

The battery case 142 includes a crimp portion 147 and a crimp portion 148 at the top thereof. The beading portion 147 is formed by press-fitting the outer periphery of the battery case 142. The beading portion 147 prevents the electrode assembly 141 received inside the battery case 142 from escaping through the top opening of the battery case 142, and may serve as a supporting portion on which the sealing body 143 is placed.

The inner circumference of the beading portion 147 is spaced apart from the second portion B3 of the first electrode at a predetermined interval. More specifically, the lower end of the inner circumference of the beading portion 147 is spaced apart from the second portion B3 of the first electrode at a predetermined interval. Further, since the second portion B3 has a low height, the second portion B3 is not substantially affected even when the battery case 142 is press-fitted from the outside to form the beading portion 147. Accordingly, the second portion B3 is not compressed by other members such as the beading portion 147, thus preventing the shape of the electrode assembly 141 from being partially deformed, thereby preventing short circuits inside the cylindrical battery 140.

Preferably, when the press-in depth of the beading portion 147 is defined as D1 and the radial length from the inner circumference of the battery case 142 to the boundary point of the second portion B3 and the third portion B2 is defined as D2, the formula d1+.d2 may be satisfied. In this case, when the battery case 142 is press-fitted to form the beading portion 147, damage to the second portion B3 is substantially prevented.

The crimp portion 148 is formed on the crimp portion 147. The crimp portion 148 has an extended and bent shape to cover the outer circumference of the cap 143a provided on the beading portion 147 and a portion of the upper surface of the cap 143 a.

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

The first current collector 144 is coupled to an upper portion of the electrode assembly 141. The first current collector 144 is made of a conductive metal material such as aluminum, copper, steel, and nickel, and is electrically connected to the uncoated portion 146a of the first electrode. The electrical connection may be made by soldering. Leads 149 may be connected to first current collector 144. The lead 149 may extend upward above the electrode assembly 141 and be coupled to the connection plate 143c or directly to the lower surface of the cap 143 a. The leads 149 may be connected to other components by soldering.

Preferably, the first current collector 144 may be integrally formed with the lead 149. In this case, the lead 149 may have an elongated plate shape extending outward from near the center of the first current collector 144.

The first current collector 144 may include a plurality of uneven portions (not shown) radially formed on a lower surface thereof. When provided with radial unevenness, the unevenness may be press-fitted into the first uncoated portion 146a of the first electrode by pressing the first current collector 144.

The first current collector 144 is coupled to an end of the first uncoated portion 146 a. The first uncoated portion 146a and the first current collector 144 may be coupled, for example, by laser welding. The laser welding may be performed in such a manner as to locally melt the base material of the current collector 144. In one modification, the first current collector 144 and the first uncoated portion 146a may be soldered in a state in which solder is interposed therebetween. In this case, the solder may have a lower melting point than the first current collector 144 and the first uncoated portion 146 a. The laser welding may be replaced by resistance welding, ultrasonic welding, spot welding, or the like.

The second current collector 145 may be coupled to a lower surface of the electrode assembly 141. One side of the second current collector 145 may be coupled to the second uncoated portion 146b by welding, and the other side may be coupled to the inner bottom surface of the battery case 142 by welding. The coupling structure between the second current collector 145 and the second non-coating portion 146b may be substantially the same as the coupling structure between the first current collector 144 and the first non-coating portion 146 a.

The uncoated portions 146a, 146b are not limited to the illustrated structure. Therefore, the uncoated portions 146a, 146b may selectively employ not only a conventional uncoated portion structure but also an uncoated portion structure of an electrode according to an embodiment (modification).

An insulator 146 may cover the first current collector 144. The insulator 146 may cover the first current collector 144 at an upper surface of the first current collector 144, thereby preventing the first current collector 144 from directly contacting the inner circumference of the battery case 142.

The insulator 146 has a lead hole 151 so that a lead 149 extending upward from the first current collector 144 may be drawn out from the lead hole. The lead 149 is pulled upward through the lead hole 151 and coupled to the lower surface of the connection plate 143c or the lower surface of the cap 143 a.

A peripheral region of an edge of the insulator 146 may be interposed between the first current collector 144 and the beading portion 147 to fix the coupling body of the electrode assembly 141 and the first current collector 144. Thereby, in the coupled body of the electrode assembly 141 and the first current collector 144, the movement of the battery 140 in the winding axis direction may be restricted, thereby improving the assembly stability of the battery 140.

The insulator 146 may be made of insulating polymer resin. In one embodiment, the insulator 146 may be made of polyethylene, polypropylene, polyimide, or polybutylene terephthalate.

The battery housing 142 may also include a table formed thereinAn exhaust portion 152 at the face. The exhaust portion 152 corresponds to a region having a smaller thickness than the peripheral region of the lower surface of the battery case 142. The exhaust portion 152 is structurally weaker than the peripheral region. Therefore, when an abnormality occurs in the cylindrical battery 140 and the internal pressure increases above a predetermined level, the gas discharge portion 152 may be ruptured so that the gas generated inside the battery case 142 is discharged to the outside. The internal pressure at which the exhaust portion 152 is ruptured may be approximately 15kgf/cm ² To 35kgf/cm ² 。

The exhaust portion 152 may be continuously or discontinuously formed while drawing a circular shape at the lower surface of the battery case 142. In one variation, the exhaust portion 152 may be formed in a straight line pattern or other patterns.

Fig. 18 illustrates a cross-sectional view of a cylindrical battery 150 according to another embodiment of the present disclosure, taken along the Y-axis direction.

Referring to fig. 18, a cylindrical battery 150 is substantially the same as the cylindrical battery 140 of fig. 17, except that the electrode structure of the second embodiment (modification) is employed in the first uncoated portion 146a of the first electrode.

Referring to fig. 18, the first uncoated portion 146a of the first electrode may have a shape in which the height of the second portion B3 gradually or stepwise decreases toward the inner circumference of the battery case 142. Preferably, a virtual line connecting the top ends of the second portions B3 may have the same or similar shape as the inner circumference of the beading portion 147.

The second portion B3 forms an inclined surface. Accordingly, when the battery case 142 is press-fitted to form the beading portion 147, the second portion B3 can be prevented from being compressed and damaged by the beading portion 147. Further, the phenomenon that the second portion B3 contacts the battery case 142 having different polarities to cause an internal short circuit can be suppressed.

The remaining components of the cylindrical battery 150 are substantially the same as those of the above-described embodiment (modification).

The uncoated portions 146a, 146b are not limited to the illustrated structure. Therefore, the uncoated portions 146a, 146b may selectively have not only a conventional uncoated portion structure but also an uncoated portion structure of an electrode according to an embodiment (modification).

Fig. 19 shows a cross-sectional view of a cylindrical battery 160 according to still another embodiment of the present disclosure, taken along the Y-axis direction.

Referring to fig. 19, the cylindrical battery 160 is substantially the same as the cylindrical batteries 140, 150 described above, except that the lead 149 connected to the first current collector 144 is directly connected to the cap 143a of the sealing body 143 through the lead hole 151 of the insulator 146, and the insulator 146 and the first current collector 144 have a structure in close contact with the lower surface of the cap 143 a.

In the cylindrical battery 160, the diameter of the first current collector 144 and the outermost diameter of the third portion B2 are smaller than the minimum inner diameter of the battery case 142. Further, the diameter of the first current collector 144 may be equal to or greater than the outermost diameter of the third portion B2.

Specifically, the minimum inner diameter of the battery case 142 may correspond to the inner diameter of the battery case 142 at the position where the beading portion 147 is formed. At this time, the outermost diameters of the first current collector 144 and the third portion B2 are smaller than the inner diameter of the battery case 142 at the position where the beading 147 is formed. Further, the diameter of the first current collector 144 may be equal to or greater than the outermost diameter of the third portion B2. A peripheral region of the edge of the insulator 146 may be interposed between the second portion B3 and the beading portion 147 in a state of being bent downward to fix the coupling body of the electrode assembly 141 and the first current collector 144.

Preferably, the insulator 146 may include a portion covering the second portion B3 and a portion covering the first current collector 144, and the portion connecting the two portions may have a form of being bent together in response to the bent shape of the beading portion 147. The insulator 146 may insulate the second portion B3 from the inner circumference of the beading portion 147 while insulating the first current collector 144 from the inner circumference of the beading portion 147.

The first current collector 144 may be positioned higher than the lower end of the beading portion 147, and may be coupled to the first and third parts B1 and B2. At this time, the press-in depth D1 of the beading portion 147 is less than or equal to the distance D2 from the inner periphery of the battery case 142 to the boundary between the second portion B3 and the third portion B2. Accordingly, the first portion B1, the third portion B2, and the first current collector 144 coupled thereto may be positioned higher than the lower end of the beading portion 147. The lower end of the beading part 147 refers to a inflection point (B) between the portion of the battery case 142 where the electrode assembly 141 is received and the beading part 147.

Since the first and third portions B1 and B2 occupy the inner space of the beading portion 147 in the radial direction, an empty space between the electrode assembly 141 and the cap 143a can be minimized. In addition, the connection plate 143c located in the empty space between the electrode assembly 141 and the cap 143a is omitted. Accordingly, the lead 149 of the first current collector 144 may be directly coupled to the lower surface of the cap 143 a. According to the above structure, the empty space in the battery can be reduced, and the energy density can be maximized in accordance with the amount of the reduced empty space.

In the cylindrical battery 160, the first and second current collectors 144 and 145 may be welded to the ends of the first and second uncoated portions 146a and 146b, respectively, in the same manner as in the above embodiments.

Fig. 20 is a sectional view illustrating a cylindrical battery 170 according to still another embodiment of the present disclosure, taken along the Y-axis.

Referring to fig. 20, the structure of the electrode assembly of the cylindrical battery 170 is substantially the same as that of the cylindrical battery 140 of fig. 17, and other structures except for the electrode assembly are changed.

Specifically, the cylindrical battery 170 includes a battery case 171, and the terminals 172 are mounted through the battery case 171. The terminals 172 are mounted through perforations formed on the closed surface (upper surface in the drawing) of the battery case 171. The terminal 172 is riveted to the penetration hole of the battery case 171 in a state in which a second gasket 173 made of an insulating material is interposed between the terminal and the battery case 171. The terminal 172 is exposed to the outside in a direction opposite to the gravitational direction.

The terminal 172 includes a terminal exposing portion 172a and a terminal inserting portion 172b. The terminal exposing portion 172a is exposed to the outside of the closing surface of the battery case 171. The terminal exposing portion 172a may be located substantially at a central portion of the closing surface of the battery case 171. The maximum diameter of the terminal exposing portion 172a may be greater than the maximum diameter of the penetration hole formed in the battery case 171. The terminal insertion part 172b may be electrically connected to the non-coating part 146a of the first electrode through a substantially central portion of the sealing surface of the battery case 171. The bottom edge of the terminal insertion part 172b may be riveted to the inner surface of the battery case 171. That is, the bottom edge of the terminal insertion part 172b may have a shape bent toward the inner surface of the battery case 171. The terminal insertion portion 172b includes a flat portion 172c in a bottom edge thereof. The maximum diameter of the staked lower portion of the terminal insertion portion 172b may be greater than the maximum diameter of the perforation of the battery case 171.

The flat portion 172c of the terminal insertion portion 172b may be welded to the center of the first current collector 144 connected to the first uncoated portion 146a of the first electrode. As the welding method, laser welding is preferable, but other welding methods such as ultrasonic welding may be used.

An insulator 174 made of an insulating material may be interposed between the first current collector 144 and the inner surface of the battery case 171. The insulator 174 covers the upper portion of the first current collector 144 and the top edge of the electrode assembly 141. Accordingly, it is possible to prevent the second portion B3 of the electrode assembly 141 from contacting the inner surfaces of the battery cases 171 having different polarities to cause a short circuit.

The thickness of the insulator 174 corresponds to or is slightly larger than the distance between the upper surface of the first current collector 144 and the inner surface of the closed portion of the battery case 171. Accordingly, the insulator 174 may be in contact with the upper surface of the first current collector 144 and the inner surface of the closed portion of the battery case 171.

The terminal insertion portion 172b of the terminal 172 may be welded to the first current collector 144 through the penetration hole of the insulator 174. The diameter of the penetration hole formed in the insulator 174 may be larger than the diameter of the caulking portion at the lower end of the terminal insertion portion 172 b. Preferably, the penetration holes may expose a lower portion of the terminal insertion part 172b and the second gasket 173.

The second gasket 173 is interposed between the battery case 171 and the terminal 172 to prevent the battery case 171 and the terminal 172 having opposite polarities from being in electrical contact with each other. Accordingly, the upper surface of the battery case 171 having an approximately flat shape may serve as a second electrode terminal (e.g., a negative electrode) of the cylindrical battery 170.

The second gasket 173 includes a gasket exposing portion 173a and a gasket inserting portion 173b. The gasket exposure portion 173a is interposed between the terminal exposure portion 172a of the terminal 172 and the battery case 171. The gasket insertion portion 173b is interposed between the terminal insertion portion 172b of the terminal 172 and the battery case 171. When the terminal insertion part 172b is riveted, the gasket insertion part 173b may be deformed together so as to be in close contact with the inner surface of the battery case 171. The second gasket 173 may be made of, for example, a polymer resin having insulation properties.

The gasket exposure portion 173a of the second gasket 173 may have an extended shape to cover the outer circumference of the terminal exposure portion 172a of the terminal 172. When the second gasket 173 covers the outer circumference of the terminal 172, it is possible to prevent a short circuit from occurring when an electrical connection portion such as a bus bar is coupled to the upper surface of the battery case 171 and/or the terminal 172. Although not shown in the drawings, the gasket exposure portion 173a may have an extended shape to cover not only the outer circumferential surface but also a portion of the upper surface of the terminal exposure portion 172 a.

When the second gasket 173 is made of a polymer resin, the second gasket 173 may be coupled to the battery case 171 and the terminal 172 by thermal fusion. In this case, the air tightness at the coupling interface between the second gasket 173 and the terminal 172 and the coupling interface between the second gasket 173 and the battery case 171 may be enhanced. Meanwhile, when the gasket exposure portion 173a of the second gasket 173 has a shape extending to the upper surface of the terminal exposure portion 172a, the terminal 172 may be integrally coupled with the second gasket 173 by insert injection molding.

In the upper surface of the battery case 171, the remaining region 175 except for the region occupied by the terminal 172 and the second gasket 173 corresponds to a second electrode terminal having a polarity opposite to that of the terminal 172.

The second current collector 176 is coupled to a lower portion of the electrode assembly 141. The second current collector 176 is made of a conductive metal material such as aluminum, steel, copper, or nickel, and is electrically connected to the second uncoated portion 146a of the second electrode.

Preferably, the second current collector 176 is electrically connected with the battery case 171. To this end, at least a portion of the edge of the second current collector 176 may be interposed and fixed between the inner surface of the battery case 171 and the first gasket 178 b. In one embodiment, at least a portion of the edge of the second current collector 176 may be fixed to the beading part 180 by welding in a state of being supported on the bottom surface of the beading part 180 formed at the bottom of the battery case 171. In a modification, at least a portion of the edge of the second current collector 176 may be directly welded to the inner wall surface of the battery case 171.

The second current collector 176 may include a plurality of uneven portions (not shown) radially formed on a surface facing the second uncoated portion 146 b. When the uneven portion is formed, the uneven portion may be press-fitted into the second uncoated portion 146b by pressing the second current collector 176.

Preferably, the ends of the second current collector 176 and the second uncoated portion 146b may be coupled by welding (e.g., laser welding). Further, the welded portions of the second current collector 176 and the second uncoated portion 146b may be spaced apart toward the core C by a predetermined distance based on the inner circumference of the beading portion 180.

The sealing body 178 for sealing the lower open end of the battery case 171 includes a cap 178a having a plate shape and a first gasket 178b. The first gasket 178b electrically separates the cap 178a and the battery case 171. The crimp 181 secures the edge of the cap 178a and the first washer 178b together. Cap 178a has a vent 179. The arrangement of the exhaust portion 179 is substantially the same as that of the above-described embodiment (modification). The lower surface of the cap 178a may be positioned higher than the lower end of the crimp portion 181. In this case, a space is formed under the cap 178a, thereby ensuring smooth exhaust. This is particularly useful when the cylindrical battery 170 is mounted such that the crimp 181 faces in the direction of gravity.

Preferably, cap 178a is made of a conductive metallic material. However, since the first gasket 178b is interposed between the cap 178a and the battery case 171, the cap 178a does not have an electric polarity. The sealing body 178 mainly seals the open end of the lower portion of the battery case 171 and serves to exhaust gas when the internal pressure of the battery 170 increases beyond a critical value. Internal pressureIs 15kgf/cm ² To 35kgf/cm ² 。

Preferably, the terminal 172 electrically connected to the uncoated portion 146a of the first electrode serves as a first electrode terminal. Further, in the upper surface of the battery case 171 electrically connected to the second uncoated portion 146a of the second electrode via the second current collector 176, a portion 175 other than the terminal 172 serves as a second electrode terminal having a different polarity from the first electrode terminal. If two electrode terminals are located at the upper portion of the cylindrical battery 170 as described above, an electrical connection member such as a bus bar may be disposed at only one side of the cylindrical battery 170. This can simplify the structure of the battery pack and improve the energy density. Further, since the portion 175 serving as the second electrode terminal has an approximately flat shape, a sufficient connection area can be ensured for connecting an electrical connection member such as a bus bar. Accordingly, the cylindrical battery 170 can reduce the resistance at the connection portion of the electrical connection member to a desired level.

Meanwhile, the structure of the uncoated portion and the structure of the electrode assembly 141 are not limited to those shown in the drawings, and may be replaced with those of the above embodiment (modification).

Fig. 21 is a sectional view illustrating a cylindrical battery 180 according to still another embodiment of the present disclosure, taken along the Y-axis.

Referring to fig. 21, the structure of the electrode assembly 141 of the cylindrical battery 180 is substantially the same as that of the cylindrical battery 150 shown in fig. 18, and components other than the electrode assembly 141 are substantially the same as those of the cylindrical battery 170 shown in fig. 20.

Accordingly, the configuration regarding the embodiment (modification) of the cylindrical batteries 150, 170 can be equally applied to the cylindrical battery 180.

Further, the structure of the electrode assembly 141 and the structure of the uncoated portion are not limited to those shown in the drawings, and may be replaced with the structure of the above embodiment (modification).

Fig. 22 is a sectional view illustrating a cylindrical battery 190 according to still another embodiment of the present disclosure, taken along the Y-axis.

Referring to fig. 22, a cylindrical battery 190 includes the electrode assembly 110 shown in fig. 14, and components other than the electrode assembly 110 are substantially the same as the cylindrical battery 140 shown in fig. 17. Accordingly, the configuration described with reference to fig. 14 and 17 can be applied to this embodiment in substantially the same manner.

Referring to fig. 10a and 22, the first and second uncoated portions 146a and 146b of the electrode assembly 110 are bent in a radial direction of the electrode assembly 110, for example, from the outer circumference to the core, to form a bent surface region F.

The first portion B1 has a lower height than the other portions, and corresponds to a section skip area a1 having no section, so it is not bent toward the core.

Preferably, the inflection surface region F may include a segment skip region a1, a height variable region a2 of the segment, and a height uniform region a3 of the segment from the core toward the outer circumference.

As shown in fig. 10c, 10d and 10e, the inflection surface region F includes an overlapping layer number uniform region b1 adjacent to the segment skip region a1 in which the overlapping layer number of segments is 10 or more.

The inflection surface region F may further include a crossover number reduction zone b2 adjacent to the outer circumference of the electrode assembly 110, in which the crossover number of the segments gradually decreases toward the outer circumference. Preferably, the overlapping layer number uniform region b1 may be set as the welding target region.

In the inflection surface region F, preferred numerical ranges as the ratio (a 2/c) of the height-variable region a2 to the radius region c including the segment, the ratio (b 1/c) of the overlapping layer number uniform region b1 to the radius region c including the segment, and the ratio of the area of the overlapping layer number uniform region b1 to the area of the inflection surface region F have been described above, and thus will not be described.

The first current collector 144 may be laser welded to the inflection surface region F of the first uncoated portion 146a, and the second current collector 145 may be laser welded to the inflection surface region F of the second uncoated portion 146 b. The welding method may be replaced by ultrasonic welding, resistance welding, spot welding, or the like.

Preferably, 50% or more of the welding region W of the first current collector 144 and the second current collector 145 may overlap the overlapping layer number uniform region b1 of the inflection surface region F. Optionally, the remaining region of the welding region W may overlap with the overlapping layer number reduction region b2 of the inflection surface region F. In terms of high welding strength, low resistance of the welding interface, and prevention of damage to the separator or the active material layer, it is more preferable that the entire welding region W overlap with the overlapping layer number uniform region b 1.

Preferably, in the overlapping layer number uniform region b1 overlapping the welding region W and optionally the overlapping layer number reduced region b2, the number of overlapping layers of the sections may be 10 to 35.

Optionally, when the number of overlapping layers of the section in the overlapping layer number reduction region b2 overlapping the welding region W is less than 10, the laser power for welding the overlapping layer number reduction region b2 may be reduced below the laser power for welding the overlapping layer number uniform region b 1. That is, when the welding region W is overlapped with both the overlapping layer number uniform region b1 and the overlapping layer number reduced region b2, the laser power may be varied according to the overlapping layer number of the sections. In this case, the welding strength of the overlapping layer number uniform region b1 may be greater than the welding strength of the overlapping layer number reduced region b 2.

In the inflection surface regions F formed at the upper and lower parts of the electrode assembly 110, the radial lengths of the segment skip regions a1 and/or the height variable regions a2 of the segments and/or the height uniform regions a3 of the segments may be the same or different from each other.

In the electrode assembly 110, the height of the first portion B1 is relatively smaller than that of the other portions. Further, as shown in fig. 14, the bending length (H) of the uncoated portion located at the innermost side of the third portion B2 is smaller than a value obtained by adding the radial length (R) of the first portion B1 to 10% of the radius of the core 112.

Therefore, even when the first uncoated portion 146a is bent toward the core, the core 112 of the electrode assembly 110 may be opened to the outside by at least 90% or more of its diameter. If the core 112 is not blocked, there is no difficulty in the electrolyte injection process, and the electrolyte injection efficiency is improved. Further, by inserting the welding jig through the core 112, the welding process between the second current collector 145 and the battery case 142 can be easily performed.

When the uncoated portions 146a, 146b have a segment structure, if the width and/or height of the segments and/or the separation pitch are adjusted to satisfy the numerical ranges of the above embodiments, when the segments are bent, the segments overlap in a plurality of layers to sufficiently secure the welding strength, and an empty space (gap) is not formed in the bending surface region F.

Preferably, the first and second current collectors 144 and 145 may have an outer diameter covering ends of the sections 61, 61' (see fig. 10 f) bent in the last convolution of the highly uniform region a3 of the first and second electrodes. In this case, welding can be performed in a state in which the segments forming the inflection surface regions F are uniformly pressed by the current collector, and even after welding, a tightly stacked state of the segments can be well maintained. The tightly stacked state refers to a state in which there is substantially no gap between the sections (as shown in fig. 10 a). The tightly stacked state helps reduce the resistance of the cylindrical battery 190 to a level suitable for rapid charging (e.g., 4 milliohms) or less.

The structure of the uncoated portions 146a, 146b may be changed to the structure according to the above embodiment (modification). Further, the conventional uncoated portion structure may be applied to any one of the uncoated portions 146a, 146b without limitation.

Fig. 23 is a sectional view illustrating a cylindrical battery 200 according to still another embodiment of the present disclosure, taken along the Y-axis.

Referring to fig. 23, a cylindrical battery 200 includes the electrode assembly 110 shown in fig. 14, and components other than the electrode assembly 110 are substantially the same as those of the cylindrical battery 180 shown in fig. 21. Accordingly, the configuration described with reference to fig. 14 and 21 can be applied to this embodiment in substantially the same manner.

Referring to fig. 10a and 23, the first and second uncoated portions 146a and 146b of the electrode assembly 110 are bent in a radial direction (e.g., from the outer circumference toward the core) of the electrode assembly 110 to form a bent surface region F.

The inflection surface region F may further include a crossover number reduction zone b2 adjacent to the outer circumference of the electrode assembly 110, in which the crossover number of the segments decreases toward the outer circumference. Preferably, the overlapping layer number uniform region b1 may be set as the welding target region.

The first current collector 144 may be laser welded to the inflection surface region F of the first uncoated portion 146a, and the second current collector 176 may be laser welded to the inflection surface region F of the second uncoated portion 146 b. The welding method may be replaced by ultrasonic welding, resistance welding, spot welding, or the like. The welding region W of the second current collector 176 and the second uncoated portion 146b may be spaced apart from the inner surface of the beading portion 180 by a predetermined distance.

Therefore, even when the uncoated portion 146a is bent toward the core, the core 112 of the electrode assembly 110 may be opened to the outside by at least 90% or more of its diameter. If the core 112 is not blocked, there is no difficulty in the electrolyte injection process, and the electrolyte injection efficiency is improved. Further, by inserting the welding jig through the core 112, the welding process between the first current collector 144 and the terminal 72 can be easily performed.

When the first and second uncoated portions 146a and 146b have a segment structure, if the width and/or height of the segments and/or the separation pitch are adjusted to satisfy the numerical ranges of the above embodiments, when the segments are bent, the segments overlap in a plurality of layers to sufficiently secure the welding strength, and an empty space (gap) is not formed in the bending surface region F.

Preferably, in the first and second current collectors 144 and 176, the regions contacting the first and second uncoated portions 146a and 146b may have an outer diameter covering the ends of the sections 61, 61' (see fig. 10 f) bent in the last convolution of the highly uniform regions a3 of the first and second electrodes. In this case, welding can be performed in a state in which the segments forming the inflection surface regions F are uniformly pressed by the current collector, and even after welding, a tightly stacked state of the segments can be well maintained. The tightly stacked state refers to a state in which there is substantially no gap between the sections (as shown in fig. 10 a). The tightly stacked state helps reduce the resistance of the cylindrical battery 190 to a level suitable for rapid charging (e.g., 4 milliohms) or less.

Fig. 24 is a sectional view illustrating a cylindrical battery 210 according to still another embodiment of the present disclosure, taken along the Y-axis.

Referring to fig. 24, a cylindrical battery 210 includes the electrode assembly 100 shown in fig. 13, and the configuration other than the electrode assembly 100 is substantially the same as the cylindrical battery 140 shown in fig. 17. Accordingly, the configuration described with reference to fig. 13 and 17 can be applied substantially identically to this embodiment.

Preferably, the first and second uncoated portions 146a and 146b of the electrode assembly 100 are divided into a plurality of sections, and the plurality of sections are bent in a radial direction of the electrode assembly 100, for example, from the outer circumference toward the core. At this time, the first and second portions B1 and B3 of the first uncoated portion 146a have a lower height than other portions and have no sections, so they are not substantially bent. This is the same for the second uncoated portion 146 b.

Also in this embodiment, the inflection surface region F may include a segment skip region a1, a segment height variable region a2, and a segment height uniform region a3 from the core toward the outer circumference. However, since the second portion B3 is not bent, the radial length of the bent surface region F may be shorter than that of the previous embodiment.

The inflection surface region F may further include a crossover number reduction zone B2 adjacent to the second portion B3 of the electrode assembly 110, in which the crossover number of the segments gradually decreases toward the outer circumference. Preferably, the overlapping layer number uniform region b1 may be set as the welding target region.

The first current collector 144 may be laser welded to the inflection surface region F of the first uncoated portion 146a, and the second current collector 145 may be laser welded to the inflection surface region F of the second uncoated portion 146 b.

The overlapping relationship of the overlapping layer number uniform region B1 and the overlapping layer number reduced region B2 with the welding region W, the outer diameters of the first current collector 144 and the second current collector 145, the configuration in which at least 10% or more of the diameter of the core is not closed by the first portion B1, and the like are substantially the same as described above.

Meanwhile, the second portion B3 has no section and has a lower height than the third portion B2. Therefore, when the first uncoated portion 146a is bent, the second portion B3 is not substantially bent. Further, since the second portion B3 is sufficiently spaced apart from the hemming portion 147, the problem of damaging the second portion B3 when the hemming portion 147 is press-fitted can be solved.

Fig. 25 is a sectional view illustrating a cylindrical battery 220 according to still another embodiment of the present disclosure, taken along the Y-axis.

Referring to fig. 25, a cylindrical battery 220 includes the electrode assembly 100 shown in fig. 24, and the configuration other than the electrode assembly 100 is substantially the same as the cylindrical battery 180 shown in fig. 21. Therefore, the configuration described with reference to fig. 21 and 24 can be applied substantially identically to this embodiment.

Preferably, the first and second non-coating portions 146a and 146b of the electrode assembly 100 are divided into a plurality of sections, and the plurality of sections are bent from the outer circumference toward the core. At this time, the first and second portions B1 and B3 of the first uncoated portion 146a have a lower height than other portions and have no sections, so they are not substantially bent. This is the same for the second uncoated portion 146 b.

Thus, in this embodiment, similar to the embodiment of fig. 24, the inflection surface region F may include a segment skip region a1, a segment height variable region a2, and a segment height uniform region a3 from the core toward the outer circumference. However, since the second portion B3 is not bent, the radial length of the bent surface region F may be shorter than that of the previous embodiment.

The first current collector 144 may be laser welded to the inflection surface region F of the first uncoated portion 146a, and the second current collector 176 may be laser welded to the inflection surface region F of the second uncoated portion 146 b.

The overlapping relationship of the overlapping layer number uniform region B1 and the overlapping layer number reduced region B2 with the welding region W, the outer diameters of the first current collector 144 and the second current collector 176, the configuration in which at least 10% or more of the diameter of the core is not closed by the first portion B1, and the like are substantially the same as described above.

In the foregoing embodiment (modification), the first current collector 144 and the second current collector 176 included in the cylindrical batteries 170, 180, 200, 220 including the terminal 172 may have the improved structure as shown in fig. 26 and 27.

The improved structure of the first current collector 144 and the second current collector 176 may help to reduce the resistance of the cylindrical battery, improve vibration resistance, and improve energy density. In particular, the first current collector 144 and the second current collector 176 are more effective when used in large cylindrical cells having a diameter to height ratio of greater than 0.4.

Fig. 26 is a top plan view illustrating a first current collector 144 according to one embodiment of the present disclosure.

Referring to fig. 23 and 26 together, the first current collector 144 may include an edge portion 144a, a first non-coating portion coupling portion 144b, and a terminal coupling portion 144c. The edge portion 144a is disposed on the electrode assembly 110. The edge portion 144a may have a substantially frame shape having an empty space (S) _open ). In the drawings of the present disclosure, only a case where the edge portion 144a has a substantially circular frame shape is shown, but the present disclosure is not limited thereto. The rim portion 144a may have a substantially rectangular rim shape, a hexagonal rim shape, an octagonal rim shape, or other rim shape that is different from the rim shape shown. The number of edge portions 144a may be increased to two or more. In this case, another edge portion in the shape of a frame may be provided to the edgeThe inner side of the portion 144 a.

The diameter of the terminal coupling portion 144c may be equal to or greater than the diameter of the flat portion 172c formed on the bottom surface of the terminal 172 so as to secure a welding area for coupling with the flat portion 172c formed on the bottom surface of the terminal 172.

The first uncoated portion coupling portion 144b extends inward from the edge portion 144a and is coupled to the uncoated portion 146a by welding. The terminal coupling portion 144c is spaced apart from the first non-coating portion coupling portion 144b and positioned inside the edge portion 144 a. The terminal coupling portion 144c may be coupled to the terminal 172 by welding. The terminal coupling portion 144c may be located, for example, approximately in an inner space surrounded by the edge portion 144a (S _open ) Is defined in the center of the (c). The terminal coupling part 144C may be disposed at a position corresponding to a hole formed in the core C of the electrode assembly 110. The terminal coupling part 144C may be configured to cover a hole formed in the core C of the electrode assembly 110 such that the hole formed in the core C of the electrode assembly 110 is not exposed to the outside of the terminal coupling part 144C. For this, the terminal coupling part 144C may have a larger diameter or width than the hole formed in the core C of the electrode assembly 110.

The first non-coating portion coupling portion 144b and the terminal coupling portion 144c may not be directly connected, but may be disposed to be spaced apart from each other and indirectly connected by the edge portion 144 a. Since the first current collector 144 has a structure in which the first non-coating portion coupling portion 144b and the terminal coupling portion 144c are not directly connected to each other but are connected by the edge portion 144a as described above, when shock and/or vibration occurs at the cylindrical battery 200, shock applied to the coupling portion between the first non-coating portion coupling portion 144b and the first non-coating portion 146a and the coupling portion between the terminal coupling portion 144c and the terminal 172 can be dispersed. In the drawings of the present disclosure, only a case where four first non-coating portion coupling portions 144b are provided is illustrated, but the present disclosure is not limited thereto. The space inside the edge portion 144a in consideration of electrolyte impregnation in terms of complexity, resistance of the shape (S _open ) The number of the first non-coated portion coupling portions 144b is differently determined in consideration of manufacturing difficulty, etc.

The first current collector 144 may further include a bridge portion 144d, the bridge portion 144d extending inward from the edge portion 144a and connected to the terminal coupling portion 144c. At least a portion of the bridging portion 144d may have a smaller cross-sectional area than the first uncoated portion coupling portion 144b and the edge portion 144 a. For example, at least a portion of the bridging portion 144d may be formed to have a smaller width and/or thickness than the first uncoated portion coupling portion 144 b. In this case, the resistance in the bridge portion 144d increases. Thus, when current flows through the bridge 144d, a relatively large resistance causes a portion of the bridge 144d to melt due to the over-current heating. Thus, the overcurrent is irreversibly blocked. The cross-sectional area of the bridge portion 144d may be adjusted to an appropriate level in consideration of the overcurrent blocking function.

The bridging portion 144d may include a tapered portion 144e having a width gradually decreasing from an inner surface of the edge portion 144a toward the terminal coupling portion 144 c. When the tapered portion 144e is provided, the rigidity of the member can be improved at the connecting portion between the bridge portion 144d and the edge portion 144 a. When the tapered portion 144e is provided, in the course of manufacturing the cylindrical battery 200, for example, the transfer device and/or the worker may easily and safely transport the first current collector 144 and/or the coupling body of the first current collector 144 with the electrode assembly 110 by clamping the tapered portion 144 e. That is, when the tapered portion 144e is provided, it is possible to prevent product defects that may occur by sandwiching portions welded with other members such as the first uncoated portion coupling portion 144b and the terminal coupling portion 144 c.

A plurality of first uncoated portion coupling portions 144b may be provided. The plurality of first uncoated portion coupling portions 144b may be disposed substantially at regular intervals from each other in the extending direction of the edge portion 144 a. The extension length of each of the plurality of first uncoated portion coupling portions 144b may be substantially equal to each other. The first uncoated portion coupling portion 144b may be coupled to the inflection surface region F of the uncoated portion 146a by laser welding. The welding may be replaced by ultrasonic welding, spot welding, or the like.

The welding pattern 144F formed by welding between the first non-coating portion coupling portion 144b and the bending surface region F may have a structure extending in the radial direction of the electrode assembly 110. The welding pattern 144f may be a line pattern or a dot array pattern.

The bonding pattern 144f corresponds to a bonding region. Therefore, the welding pattern 144F preferably overlaps the overlapping layer number uniform region b1 of the inflection surface region F by 50% or more. The welding pattern 144f that does not overlap the overlapping layer number uniform region b1 may overlap the overlapping layer number reduced region b 2. More preferably, the entire welding pattern 144F may overlap the overlapping layer number uniform region b1 of the inflection surface region F. In the inflection surface region F below the region where the welding pattern 144F is formed, the number of overlapped layers of the segment is preferably 10 or more in the overlapped layer number uniform region b1 and optionally the overlapped layer number reduced region b 2.

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

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

In the case where the plurality of first non-coating portion coupling portions 144b and/or the bridging portions 144d are provided as described above, if the distance between the first non-coating portion coupling portions 144b and/or the distance between the bridging portions 144d and/or the distance between the first non-coating portion coupling portions 144b and the bridging portions 144d are uniformly formed, the current flowing from the first non-coating portion coupling portions 144b to the bridging portions 144d or the current flowing from the bridging portions 144d to the first non-coating portion coupling portions 144b may be smoothly and uniformly formed.

The bridge portion 144d may include a notched portion N formed to partially reduce the cross-sectional area of the bridge portion 144d. The cross-sectional area of the notched portion N may be adjusted, for example, by locally reducing the width and/or thickness of the bridging portion 144d. When the notched portions N are provided, the resistance in the formation region of the notched portions N increases, thereby realizing rapid current interruption when overcurrent occurs.

The notched portions N are preferably disposed in regions corresponding to the overlapping layer number uniform regions b1 of the electrode assembly 110 to prevent substances generated during rupture from flowing into the electrode assembly 110. This is because, in this region, the number of overlapping layers of the sections of the uncoated portion 146a is maintained to be maximum, and thus the overlapping sections can be used as a mask.

The notched portion N may be surrounded by an insulating tape. Accordingly, since heat generated at the notched portion N is not dissipated to the outside, the notched portion N may be broken more rapidly when an overcurrent flows through the bridging portion 144 d.

Fig. 27 is a top plan view illustrating a structure of a second current collector 176 according to an embodiment of the present disclosure.

Referring to fig. 23 and 27 together, the second current collector 176 is disposed under the electrode assembly 110. In addition, the second current collector 176 may be configured to electrically connect the uncoated portion 146b of the electrode assembly 110 and the battery case 171. The second current collector 176 is made of a metal material having conductivity, and is electrically connected to the folded surface region F of the uncoated portion 146 b. Further, the second current collector 176 is electrically connected to the battery case 171. An edge portion of the second current collector 176 may be interposed and fixed between the inner surface of the battery case 171 and the first gasket 178 b. Specifically, an edge portion of the second current collector 176 may be interposed between the lower surface of the beading portion 180 of the battery case 171 and the first gasket 178 b. However, the present disclosure is not limited thereto, and the edge portion of the second current collector 176 may be welded to the inner wall surface of the battery case 171 in a region where the beading portion 180 is not formed.

The second current collector 176 may include: a support portion 176a disposed under the electrode assembly 110; a second uncoated portion coupling portion 176b extending from the supporting portion 176a approximately in the radial direction of the electrode assembly 110 and coupled to the bent surface region F of the uncoated portion 146 b; and a case coupling part 176c extending from the support part 176a toward the inner surface of the battery case 171 approximately in an oblique direction based on the radial direction of the electrode assembly 110 and coupled to the inner surface of the battery case 171. The second uncoated portion coupling portion 176b and the case coupling portion 176c are indirectly connected by means of the supporting portion 176a, and are not directly connected to each other. Accordingly, when external impact is applied to the cylindrical battery 200 of the present disclosure, the possibility of damaging the coupling parts of the second current collector 176 and the electrode assembly 110 and the coupling parts of the second current collector 176 and the battery case 171 may be minimized. However, the second current collector 176 of the present disclosure is not limited to a structure in which the second uncoated portion coupling portion 176b and the case coupling portion 176c are only indirectly connected. For example, the second current collector 176 may have a structure that does not include the supporting portion 176a for indirectly connecting the second uncoated portion coupling portion 176b and the case coupling portion 176c and/or a structure that directly connects the uncoated portion 146b and the case coupling portion 176c to each other.

The support portion 176a and the second non-coating portion coupling portion 176b are disposed under the electrode assembly 110. The second uncoated portion coupling portion 176b is coupled to the inflection surface region F of the uncoated portion 146b. The supporting portion 176a may be coupled to the non-coating portion 146b in addition to the second non-coating portion coupling portion 176 b. The second uncoated portion coupling portion 176b and the folded surface region F of the uncoated portion 146b may be coupled by welding. The welding may be replaced by ultrasonic welding, spot welding, or the like. When the beading part 180 is formed on the battery case 171, the supporting part 176a and the second uncoated part coupling part 176b are located at a position higher than the beading part 180.

The support portion 176a has a collector hole 176d formed at a position corresponding to the hole formed at the core C of the electrode assembly 110. The core C and the current collector hole 176d of the electrode assembly 110, which communicate with each other, may serve as a passage for inserting a welding rod for welding between the terminal 172 and the terminal coupling part 144C of the first current collector 144 or for irradiating a laser beam.

And the radius (r) of the hole formed in the core C of the electrode assembly 110 _c ) In contrast, the current collector hole 176d may have 0.5r _c The radius above. If the radius of the current collector hole 176d is 0.5r _c To 1.0r _c It is possible to prevent the wound structure of the separator or the electrode near the core C of the electrode assembly 110 from being pushed out of the core C due to the exhaust pressure when the exhaust occurs in the cylindrical battery 200. When the radius of the current collector hole 176d is greater than 1.0r _c When the core C is opened to the maximum, the electrolyte can be easily injected during the electrolyte injection.

When the plurality of second non-coating portion coupling portions 176b are provided, the plurality of second non-coating portion coupling portions 176b may have a shape extending approximately radially from the support portion 176a of the second current collector 176 toward the side wall of the battery case 171. The plurality of second uncoated portion coupling portions 176b may be positioned to be spaced apart from each other along the periphery of the supporting portion 176 a.

A plurality of housing coupling portions 176c may be provided. In this case, the plurality of case coupling parts 176c may have a shape extending approximately radially from the center of the second current collector 176 toward the side wall of the battery case 171. Accordingly, electrical connection between the second current collector 176 and the battery case 171 may be made at a plurality of points. Since coupling for electrical connection is performed at a plurality of points, a coupling area can be maximized, thereby minimizing resistance. The plurality of case coupling parts 176c may be positioned to be spaced apart from each other along the outer periphery of the supporting part 176 a. At least one housing coupling portion 176c may be positioned between second uncoated portion coupling portions 176b adjacent to each other. The plurality of case coupling parts 176c may be coupled to, for example, a beading part 180 in the inner surface of the battery case 171. The case coupling portion 176c may be coupled to the lower surface of the beading portion 180, particularly by laser welding. The welding may be replaced by ultrasonic welding, spot welding, or the like. By coupling the plurality of case coupling parts 176c to the beading part 180 by welding in this way, the current paths are radially dispersed, thereby limiting the resistance level of the cylindrical battery 200 to about 4 milliohms or less. Further, since the lower surface of the beading part 180 has a shape extending in a direction approximately parallel to the upper surface of the battery case 171 (i.e., in a direction approximately perpendicular to the side wall of the battery case 171), and the case coupling part 176c also has a shape extending in the same direction (i.e., in the radial direction and the circumferential direction), the case coupling part 176c can be stably in contact with the beading part 180. Further, since the case coupling portion 176c is stably in contact with the flat portion of the beading portion 180, the two components can be smoothly welded, thereby improving coupling force between the two components and minimizing an increase in resistance at the coupling portion.

The case coupling part 176c may include a contact part 176e coupled to the inner surface of the battery case 171 and a connection part 176f for connecting the support part 176a and the contact part 176 e.

The contact portion 176e is coupled to the inner surface of the battery case 171. In the case where the beading 180 is formed on the battery case 171, the contact portion 176e may be coupled to the beading 180 as described above. More specifically, the contact portion 176e may be electrically coupled to a flat portion at a lower surface of the beading 180 formed on the battery case 171, and may be interposed between the lower surface of the beading 180 and the first gasket 178 b. In this case, the contact portion 176e may have a shape extending a predetermined length on the beading 180 in the circumferential direction of the battery case 171 for stable contact and coupling.

The connection portion 176f may be bent at an obtuse angle. The inflection point may be higher than the intermediate point of the connection 176f. When the connection portion 176f is bent, the contact portion 176e may be stably supported on the flat surface of the beading portion 180. The connection portion 176f may be divided into a lower portion and an upper portion based on the inflection point, and the length of the lower portion may be greater than that of the upper portion. Further, the inclination angle with respect to the surface of the supporting portion 176a is larger at the lower portion of the inflection point than at the upper portion. If the connection portion 176f is bent, the connection portion 176f may buffer pressure (force) applied in the vertical direction of the battery case 171. For example, if pressure is transmitted to the contact portion 176e during the sizing of the battery case 171 such that the contact portion 176e moves vertically toward the support portion 176a, the inflection point of the connection portion 176f may move upward to deform the shape of the connection portion 176f, thereby buffering the stress.

Meanwhile, the maximum distance from the center of the second current collector 176 to the end of the second non-coating portion coupling portion 176b in the radial direction of the electrode assembly 110 is preferably equal to or less than the inner diameter of the battery case 171 in the region where the beading 180 is formed, i.e., the minimum inner diameter of the battery case 171. This is to prevent the end of the second non-coating portion coupling portion 176b from pressing the edge of the electrode assembly 110 during the size setting process for compressing the battery case 171 in the height direction.

The second uncoated portion coupling portion 176b includes a hole 176g. The holes 176g may serve as channels through which electrolyte may move. The welding pattern 176h formed by welding between the second non-coating portion coupling portion 176b and the bending surface region F may have a structure extending in the radial direction of the electrode assembly 110. The welding pattern 176h may be a line pattern or a dot array pattern.

The bonding pattern 176h corresponds to a bonding region. Therefore, the welding pattern 176h preferably overlaps the overlapping layer number uniform region b1 of the inflection surface region F by 50% or more. The welding pattern 176h that does not overlap the overlapping layer number uniform region b1 may overlap the overlapping layer number reduced region b 2. More preferably, the entire welding pattern 176h may overlap the overlapping layer number uniform region b1 of the inflection surface region F. In the inflection surface region F above the region where the welding pattern 176h is formed, the number of overlapped layers of the segment is preferably 10 or more in the overlapped layer number uniform region b1 and optionally the overlapped layer number reduced region b 2.

The diameters of the first current collector 144 and the second current collector 176 are different from each other. The diameter is the peripheral diameter of the contact area between the inflection surface region F and the current collector. The diameter is defined as the maximum value in the distance between two points at which a straight line passing through the center of the core C of the electrode assembly intersects with the boundary of the contact region. Since the second current collector 176 is located inside the beading portion 180, the diameter of the second current collector 176 is smaller than that of the first current collector 144. Further, the length of the welding pattern 144f of the first current collector 144 is longer than the length of the welding pattern 176h of the second current collector 176. Preferably, the welding pattern 144f and the welding pattern 176h may extend from substantially the same point toward the outer circumference with respect to the center of the core C.

An advantage of the cylindrical batteries 170, 180, 200, 220 according to one embodiment of the present disclosure is that electrical connection can be made at the upper portion thereof.

Fig. 28 is a top plan view showing a state in which a plurality of cylindrical batteries 200 are electrically connected, and fig. 29 is a partial enlarged view of fig. 28. The cylindrical battery 200 may be replaced with cylindrical batteries 170, 180, 220 having different structures.

Referring to fig. 28 and 29, a plurality of cylindrical batteries 200 may be connected in series and parallel at the upper portion of the cylindrical batteries 200 using a bus bar 210. The number of cylindrical batteries 200 may be increased or decreased in consideration of the capacity of the battery pack.

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

Preferably, the plurality of cylindrical batteries 200 may be arranged in a plurality of columns and a plurality of rows. Columns are arranged in the up-down direction on the figure, and rows are arranged in the left-right direction on the figure. Further, in order to maximize space efficiency, the cylindrical battery 200 may be arranged in the most compact packaging structure. When the equilateral triangle is formed by connecting the centers of the terminals 172 exposed to the outside of the battery case 171 to each other, a tight package structure is formed. Preferably, the bus bars 210 connect the cylindrical batteries 200 arranged in the same column in parallel with each other, and connect the cylindrical batteries 200 arranged in adjacent two columns in series with each other.

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

The body portion 211 may extend along the column of cylindrical cells 200 between adjacent terminals 172. Alternatively, the body portion 211 may extend along a row of the cylindrical batteries 1, and the body portion 211 may be regularly bent in a zigzag shape.

The plurality of first bus bar terminals 212 may extend from one side of the body portion 211 and may be electrically coupled to the terminals 172 of the cylindrical battery 200 located at one side. The electrical connection between the first bus bar terminal 212 and the terminal 172 may be achieved by laser welding, ultrasonic welding, or the like.

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

Preferably, the body portion 211, the plurality of first bus bar terminals 212, and the plurality of second bus bar terminals 213 may be made of one conductive metal plate. The metal plate may be, for example, an aluminum plate or a copper plate, but the present disclosure is not limited thereto. In a modification, the body portion 211, the plurality of first bus bar terminals 212, and the second bus bar terminals 213 may be manufactured as separate pieces and then coupled to each other by welding or the like.

The cylindrical battery 200 of the present disclosure as described above has a structure in which the resistance is minimized by enlarging the welding area by means of the bent surface region F, multiplexing the current path by means of the second current collector 176, minimizing the current path length, and the like. The AC resistance of cylindrical battery 200, measured by means of a resistance meter, between the positive and negative electrodes (i.e., between terminal 172 and flat surface 171a around terminal 172) may be about 0.5 milliohms to 4 milliohms (preferably 1 milliohm to 4 milliohms) suitable for rapid charging.

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

Further, since the terminal 172 of the cylindrical battery 200 and the flat surface 171a around the terminal 172 have a large area, the coupling area of the bus bar 210 can be sufficiently ensured to sufficiently reduce the resistance of the battery pack including the cylindrical battery 200.

Further, since electrical wiring may be performed at the upper portion of the cylindrical battery 200, there is an advantage in that the energy density per unit volume of the battery module/battery pack may be maximized.

The cylindrical battery according to the above embodiment (modification) may be used to manufacture a battery pack.

Referring to fig. 30, a battery pack 300 according to an embodiment of the present disclosure includes: an aggregate in which the cylindrical batteries 301 are electrically connected; and a battery pack housing 302 for containing the aggregate. The cylindrical battery 301 may be any one of the batteries according to the above embodiment (modification). In the drawings, for convenience of illustration, components such as bus bars for electrical connection of the cylindrical battery 301, a cooling unit, external terminals, and the like are not depicted.

The battery pack 300 may be mounted to a vehicle. The vehicle may be, for example, an electric vehicle, a hybrid electric vehicle, or a plug-in hybrid vehicle. The vehicle includes a four-wheeled vehicle or a two-wheeled vehicle.

Fig. 31 is a diagram schematically illustrating a vehicle including the battery pack 300 of fig. 30 according to an embodiment of the present disclosure.

Referring to fig. 31, a vehicle V according to an embodiment of the present invention includes a battery pack 300 according to an embodiment of the present disclosure. According to one embodiment of the present disclosure, the vehicle V is operated by receiving power from the battery pack 300.

According to the present disclosure, since the uncoated portions protruding from the upper and lower parts of the electrode assembly themselves serve as electrode tabs, it is possible to reduce the internal resistance of the battery and increase the energy density.

According to yet another embodiment of the present disclosure, a cylindrical battery including an improved design for electrical wiring at an upper portion thereof may be provided.

In particular, the present disclosure may provide a cylindrical battery having a diameter to height ratio of 0.4 or more and a resistance of 4 milliohms or less, and may provide a battery pack and a vehicle including the cylindrical battery.

The present disclosure has been described in detail. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the scope of the disclosure will become apparent to those skilled in the art from this detailed description.

Claims

1. An electrode assembly in which a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode are wound based on a winding axis to define a core and an outer circumference,

wherein the first electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion uncoated with the active material layer,

at least a portion of the first uncoated portion itself is defined as an electrode tab,

the first uncoated portion includes a first portion adjacent to the core of the electrode assembly, a second portion adjacent to the outer periphery of the electrode assembly, and a third portion interposed between the first portion and the second portion, an

The first portion or the second portion has a height in the winding axis direction smaller than that of the third portion.

2. The electrode assembly according to claim 1,

wherein the third portion is defined as the electrode tab in a state of being bent in a radial direction of the electrode assembly.

3. The electrode assembly according to claim 1,

wherein the second portion and the third portion are defined as the electrode tab in a state of being bent in a radial direction of the electrode assembly.

4. The electrode assembly according to claim 1,

wherein at least a partial region of the third portion is divided into a plurality of sections that are individually bendable.

5. The electrode assembly according to claim 4,

wherein each of the plurality of segments has a geometry of one or more straight lines, one or more curved lines, or a combination thereof.

6. The electrode assembly according to claim 5,

wherein in each of the plurality of sections, the width of the lower portion is greater than the width of the upper portion.

7. The electrode assembly according to claim 5,

wherein in each of the plurality of sections, the width of the lower portion is the same as the width of the upper portion.

8. The electrode assembly according to claim 5,

wherein each of the plurality of sections has a width that gradually decreases from a lower portion to an upper portion.

9. The electrode assembly according to claim 5,

wherein each of the plurality of sections has a width that gradually decreases and then increases from a lower portion to an upper portion.

10. The electrode assembly according to claim 5,

wherein each of the plurality of sections has a width that gradually increases and then decreases from a lower portion to an upper portion.

11. The electrode assembly according to claim 5,

wherein each of the plurality of sections has a width that gradually increases from a lower portion to an upper portion and then remains constant.

12. The electrode assembly according to claim 5,

wherein each of the plurality of sections has a width that gradually decreases from a lower portion to an upper portion and then remains constant.

13. The electrode assembly according to claim 5,

wherein the plurality of sections have lower internal angles that increase individually, in groups, or in units of groups in one direction parallel to the winding direction.

14. The electrode assembly according to claim 13,

Wherein the lower internal angles of the plurality of sections individually increase, group-wise increase, or increase in a plurality of group units in the range of 60 degrees to 85 degrees in the one direction parallel to the winding direction.

15. The electrode assembly according to claim 4,

wherein each of the plurality of sections has a geometry in which a width gradually decreases from a lower portion to an upper portion, and a lower inner angle θ of a section located in a convolution having a radius r based on the core of the electrode assembly falls within an angular range of the following formula:

wherein D is the width of the segment in the winding direction; r is the radius of the convolutions comprising the segment; h is the height of the segment; p is the separation pitch of the segments.

16. The electrode assembly according to claim 5,

wherein each of the plurality of sections has a side formed from one or more straight lines, one or more curved lines, or a combination thereof.

17. The electrode assembly according to claim 5,

wherein each of the plurality of sections has a side portion that is outwardly convex or inwardly convex.

18. The electrode assembly according to claim 5,

wherein the corners of the upper portion of each of the plurality of sections have a rounded shape.

19. The electrode assembly according to claim 5,

wherein the plurality of segments are configured such that the geometry varies individually, in groups, or in two or more groups in one direction parallel to the winding direction.

20. The electrode assembly according to claim 4,

wherein a cutting groove is interposed between sections adjacent to each other in the winding direction, and a lower portion of the cutting groove includes a bottom portion and a rounded portion for connecting both ends of the bottom portion to side portions of the sections on both sides of the cutting groove.

21. The electrode assembly according to claim 20,

wherein the rounded portion has a radius of curvature greater than 0 and equal to or less than 0.1 mm.

22. The electrode assembly according to claim 20,

wherein the rounded portion has a radius of curvature of 0.01mm to 0.05 mm.

23. The electrode assembly according to claim 20,

wherein the bottom is flat.

24. The electrode assembly according to claim 20,

wherein a separation pitch defined as a space between two points where a line extending from the side portions of two sections located at both sides of the cutting groove and a line extending from the bottom of the cutting groove intersect is 0.05mm to 1.00mm.

25. The electrode assembly according to claim 20,

wherein the plurality of sections are made of aluminum foil, and are defined as a separation pitch of 0.05mm to 1.00mm of a space between two points where a line extending from the side portions of two sections located at both sides of the cutting groove intersects a line extending from the bottom of the cutting groove.

26. The electrode assembly according to claim 20,

wherein the plurality of sections are configured such that a separation pitch defined as a space between two points at which a line extending from the side portions of two sections located at both sides of the cutting groove intersects a line extending from the bottom of the cutting groove varies in one direction parallel to the winding direction.

27. The electrode assembly according to claim 26,

wherein the separation pitches of the plurality of sections are changed in groups in one direction parallel to the winding direction or in two or more groups.

28. The electrode assembly according to claim 20,

wherein the bottom of the cutting groove is spaced apart from the active material layer by a predetermined distance.

29. The electrode assembly according to claim 28,

wherein a separation distance between the bottom of the cutting groove and the active material layer is 0.2mm to 4mm.

30. The electrode assembly according to claim 28,

wherein a separation distance between the bottom of the cutting groove and the active material layer varies in one direction parallel to the winding direction.

31. The electrode assembly according to claim 30,

wherein the separation distance between the bottom of the cutting groove and the active material layer is changed individually, in groups, or in two or more groups in one direction parallel to the winding direction.

32. The electrode assembly according to claim 20,

wherein bending regions of the plurality of segments in the radial direction of the electrode assembly are located within a range of 0mm to 1mm above the lower end of the cutting groove.

33. The electrode assembly according to claim 4,

wherein, in each of the plurality of sections, a circumferential angle of an arc formed by a lower end of the section based on a core center of the electrode assembly is 45 degrees or less.

34. The electrode assembly according to claim 4,

wherein, in each of the plurality of sections, assuming that a radius of a convolution including the section is r based on a core center of the electrode assembly and a width of the section in the winding direction is D (r), D (r) satisfies the following formula:

1≤D(r)≤(2*π*r/360°)*45°。

35. The electrode assembly according to claim 34,

wherein, in each of the plurality of sections, as a radius r of a winding turn where the section is located based on the core center of the electrode assembly increases, a width D (r) in the winding direction gradually or stepwise increases or decreases.

36. The electrode assembly according to claim 34,

wherein, in each of the plurality of sections, as the radius r of the winding turn where the section is located based on the core center of the electrode assembly increases, the width D (r) in the winding direction gradually or stepwise increases and then gradually or stepwise decreases, or gradually or stepwise decreases and then gradually or stepwise increases.

37. The electrode assembly according to claim 33,

wherein, in the plurality of sections, the circumferential angle is substantially the same based on the core center of the electrode assembly.

38. The electrode assembly according to claim 33,

wherein the widths of the plurality of sections in the winding direction increase at substantially the same rate in one direction parallel to the winding direction of the electrode assembly.

39. The electrode assembly according to claim 4,

Wherein, in each of the plurality of sections, as a radius r of a winding turn where the section is located based on the core center of the electrode assembly increases, a width in the winding direction gradually or stepwise increases in a range of 1mm to 11 mm.

40. The electrode assembly according to claim 1,

wherein in at least a partial region of the third portion, the height in the winding axis direction varies gradually or stepwise in one direction parallel to the winding direction.

41. The electrode assembly according to claim 40,

wherein in at least a partial region of the second and third portions, the height in the winding axis direction is gradually or stepwise varied in one direction parallel to the winding direction.

42. The electrode assembly according to claim 40,

wherein the third portion is divided into a plurality of regions having different heights in one direction parallel to the winding direction, and the height of the uncoated portion in the plurality of regions is gradually or stepwise increased in one direction parallel to the winding direction.

43. The electrode assembly according to claim 4,

wherein the first uncoated portion comprises a height-variable region in which the height of the section is from a first height h ₁ Gradually increase to the N-1 th height h _N-1 Wherein N is a natural number of 2 or more and the height of the segment in the height uniformity region is maintained at an Nth height h _N ，h _N Is greater than h _N-1 。

44. The electrode assembly according to claim 43,

wherein, N is a natural number from 2 to 30.

45. The electrode assembly according to claim 43,

wherein the height h _k Is assigned to a plurality of sections and has the height h _k Is provided in at least one convolution, wherein k is a natural number from 1 to N.

46. The electrode assembly according to claim 43,

wherein when it includes a height h _k The initial radius of the convolutions of the segment of (a) is defined as r _k When the core of the electrode assembly is not located at the r by at least 90% or more of its diameter _k The bend of the segment at which k is a natural number from 1 to N.

47. The electrode assembly according to claim 43,

wherein when it includes a height h _k The initial radius of the convolutions of the segment of (a) is defined as r _k And the radius of the core is r _c Where k is a natural number from 1 to N, the height h of the segment _k The following formula is satisfied:

2mm≤h _k ≤r _k -α*r _c wherein α is 0.90 to 1.

48. The electrode assembly according to claim 4,

Wherein the electrode assembly sequentially includes a segment skip region having no segments, a height variable region having a variable height in which the segments and a height uniform region having a uniform height in which the segments are disposed in the height variable region and the height uniform region in a radial direction based on a section along the winding axis direction, and the plurality of segments are bent in the radial direction of the electrode assembly to form a bent surface region.

49. The electrode assembly according to claim 48,

wherein the first portion is not divided into sections, and the section skip area corresponds to the first portion.

50. The electrode assembly according to claim 48,

wherein the third portion is divided into a plurality of sections that are individually bendable, and the height-variable region and the height-uniform region correspond to the third portion.

51. The electrode assembly according to claim 48,

wherein the second portion and the third portion are divided into a plurality of sections that are individually bendable, and the height-variable region and the height-uniform region correspond to the second portion and the third portion.

52. The electrode assembly according to claim 48,

Wherein in the height-variable region and the height-uniform region, the maximum height h of the section _max The following formula is satisfied:

h _max ≤W _foil -W _scrap,min -W _margin,min -W _gap

wherein W is _foil Is the width of the current collector foil before forming the segments; w (W) _scrap,min Is the width corresponding to the minimum cut scrap margin when forming a section by cutting the current collector foil; w (W) _margin,min Is a width corresponding to a minimum meandering margin of the diaphragm; and W is _gap Is a width corresponding to an insulation gap between an end of the separator and an end of the second electrode facing the first electrode with the separator interposed therebetween.

53. The electrode assembly according to claim 52,

wherein the first electrode is a positive electrode, and the insulation gap is in the range of 0.2mm to 6 mm.

54. The electrode assembly according to claim 52,

wherein the first electrode is a negative electrode, and the insulation gap is in the range of 0.1mm to 2 mm.

55. The electrode assembly according to claim 52,

wherein the minimum cutting waste margin is in the range of 1.5mm to 8 mm.

56. The electrode assembly according to claim 52,

wherein the minimum meandering margin is in the range of 0mm to 1 mm.

57. The electrode assembly according to claim 52,

Wherein the minimum cutting waste margin is zero.

58. The electrode assembly according to claim 48,

wherein the height of the sections provided in the height-variable region is gradually or stepwise increased in the range of 2mm to 10 mm.

59. The electrode assembly according to claim 48,

wherein a ratio of a radial length of the segment skip region to a radius of the electrode assembly other than the core in the radial direction of the electrode assembly is 10% to 40%.

60. The electrode assembly according to claim 48,

wherein a ratio of a radial length of the height-variable region to a radial length corresponding to the height-variable region and the height-uniform region in the radial direction of the electrode assembly is 1% to 50%.

61. The electrode assembly according to claim 48,

wherein a ratio of a length of an electrode region corresponding to the segment skip region to an entire length of the first electrode is 1% to 30%.

62. The electrode assembly according to claim 48,

wherein a ratio of a length of an electrode region corresponding to the height variable region to an entire length of the first electrode is 1% to 40%.

63. The electrode assembly according to claim 48,

Wherein a ratio of a length of an electrode region corresponding to the highly uniform region to an entire length of the first electrode is 50% to 90%.

64. The electrode assembly according to claim 4,

wherein at least one selected from the width in the winding direction and the height in the winding axis direction of the plurality of sections gradually or stepwise increases in one direction parallel to the winding direction.

65. The electrode assembly according to claim 4,

wherein at least one of the width in the winding direction and the height in the winding axis direction of the plurality of sections gradually or gradually increases and then gradually or gradually decreases, or gradually decreases and then gradually or gradually increases in one direction parallel to the winding direction.

66. The electrode assembly according to claim 4,

wherein the plurality of segments form a plurality of segment groups along one direction parallel to the winding direction of the electrode assembly, and segments belonging to the same segment group are substantially identical to each other in terms of width in the winding direction and height in the winding axis direction.

67. The electrode assembly of claim 66,

Wherein at least one of the width in the winding direction and the height in the winding axis direction of the segments belonging to the same segment group gradually or stepwise increases in one direction parallel to the winding direction of the electrode assembly.

68. The electrode assembly according to claim 61,

wherein the lower inner angles of the segments belonging to the same segment group are gradually or stepwise increased in groups or in two or more groups in one direction parallel to the winding direction of the electrode assembly.

69. The electrode assembly of claim 66,

wherein when widths in the winding direction of three segment groups sequentially adjacent to each other in one direction parallel to the winding direction of the electrode assembly are W1, W2, and W3, respectively, a combination of segment groups having W3/W2 smaller than W2/W1 is included.

70. The electrode assembly according to claim 1,

wherein the first portion is not divided into sections, and the first portion is not bent in a radial direction of the electrode assembly.

71. The electrode assembly according to claim 1,

wherein the second portion is not divided into sections, and the second portion is not bent in a radial direction of the electrode assembly.

72. The electrode assembly according to claim 20,

wherein an insulating coating layer is formed at a boundary between the active material layer and a region of an uncoated portion provided in a portion where the bottom of the cutting groove is separated from the active material layer.

73. The electrode assembly of claim 72,

wherein the insulating coating layer includes a polymer resin and an inorganic filler dispersed in the polymer resin.

74. The electrode assembly of claim 72,

wherein the insulating coating layer is formed to cover a boundary portion of the active material layer and the first uncoated portion in the winding direction.

75. The electrode assembly of claim 74,

wherein the insulating coating layer is formed to cover the boundary portion of the active material layer and the first uncoated portion with a width of 0.3mm to 5mm in the winding axis direction.

76. The electrode assembly of claim 72,

wherein an end of the insulating coating layer is located in a range of-2 mm to 2mm in the winding axis direction based on an end of the separator.

77. The electrode assembly of claim 76,

wherein the insulating coating layer is exposed outside the separator.

78. The electrode assembly of claim 72,

wherein the lower end of the cutting groove is spaced apart from the insulating coating layer by a distance of 0.5mm to 2 mm.

79. The electrode assembly of claim 78,

wherein an end of the insulating coating layer in the winding axis direction is located in a range of-2 mm to +2mm based on the lower end of the cutting groove.

80. The electrode assembly of claim 72,

wherein, in the plurality of sections, a separation distance between the bottom of the cutting groove and the active material layer varies in one direction parallel to the winding direction.

81. The electrode assembly of claim 80,

wherein in the plurality of sections, the separation distance varies alone, in groups, or in two or more groups.

82. The electrode assembly of claim 72,

wherein the second electrode includes a second active material portion coated with an active material layer in the winding direction, an end of the second active material portion being located between an upper end and a lower end of the insulating coating layer in the winding axis direction.

83. The electrode assembly according to claim 1,

Wherein the third portion and optionally the second portion are divided into a plurality of sections that are individually bendable, and the electrode assembly comprises a bending surface region formed by bending the plurality of sections in a radial direction of the electrode assembly.

84. The electrode assembly of claim 83 wherein,

wherein, when the number of sections intersecting with a virtual line parallel to the winding axis direction at any radial position of the inflection surface region based on the core center of the electrode assembly is defined as the number of overlapping layers of sections at the respective radial positions, the inflection surface region includes an overlapping layer number uniform region in which the overlapping layer number of sections is uniform from the core toward the outer circumference and an overlapping layer number reduced region located outside the overlapping layer number uniform region such that the overlapping layer number of sections gradually decreases toward the outer circumference.

85. The electrode assembly of claim 84,

wherein a radial length of the overlapping layer number uniform region and the overlapping layer number reduced region based on the core center of the electrode assembly corresponds to a radial length of a radial region where the convolution including the plurality of sections is located.

86. The electrode assembly of claim 84,

wherein the electrode assembly sequentially includes a segment skip region having no segments, a height variable region having a variable height in the segments, and a height uniformity region having a uniform height in the segments in the radial direction, and a starting radius of the overlapping layer number uniformity region based on the core center of the electrode assembly corresponds to a starting radius of the height variable region.

87. The electrode assembly of claim 84,

wherein the number of overlapping layers of the sections is 10 to 35 in the area of uniform number of overlapping layers.

88. The electrode assembly of claim 84,

wherein the first electrode is a positive electrode, and in the overlapping layer number uniform region, an overlapping thickness of the segments is between 100 μm and 875 μm.

89. The electrode assembly of claim 84,

wherein the first electrode is a negative electrode, and in the overlapping layer number uniform region, an overlapping thickness of the segments is between 50 μm and 700 μm.

90. The electrode assembly of claim 84,

wherein a ratio of a radial length of the overlapping layer number uniform region to a radial length of the overlapping layer number uniform region and the overlapping layer number reduced region is 30% to 85%.

91. The electrode assembly of claim 84, further comprising:

a current collector welded to the inflection surface region,

wherein, in the radial direction of the electrode assembly, the welding region of the current collector overlaps the overlapping layer number uniformity region by at least 50%.

92. The electrode assembly of claim 91,

wherein, in the radial direction of the electrode assembly, a region of the welding region of the current collector that does not overlap the overlapping layer number uniformity region overlaps the overlapping layer number reduction region.

93. The electrode assembly of claim 91,

wherein an edge of the current collector is disposed on the inflection surface region to cover an end of the inflection of the outermost section in the radial direction of the electrode assembly and welded to the inflection surface region.

94. The electrode assembly of claim 91,

wherein the current collector and the welding areaHas a weld strength of at least 2kgf/cm ² Or larger.

95. The electrode assembly of claim 91,

wherein the welding strength of the current collector and the welding area is at least 4kgf/cm ² Or larger.

96. The electrode assembly according to claim 1,

wherein the first uncoated portion is made of a metal foil, and

the metal foil has an elongation of 1.5% to 3.0% and a tensile strength of 25kgf/mm ² To 35kgf/mm ² 。

97. The electrode assembly of claim 96,

wherein the metal foil is aluminum foil.

98. The electrode assembly of claim 96,

wherein the first electrode has a warp length of less than 20 mm.

99. The electrode assembly according to claim 1,

wherein, in the first active material portion, a ratio of a length of a short side parallel to the winding axis direction to a length of a long side parallel to the winding direction is 1% to 4%.

100. The electrode assembly according to claim 1,

wherein the height of the second portion gradually or stepwise decreases from the core of the electrode assembly toward the outer periphery.

101. The electrode assembly according to claim 1,

wherein the second portion and the third portion are divided into a plurality of sections that are individually bendable, and a section included in the second portion is larger than a section included in the third portion in at least one of a width in the winding direction and a height in the winding axis direction.

102. The electrode assembly according to claim 4,

wherein the third portion includes a segment skip region having no segments in the winding direction of the electrode assembly.

103. The electrode assembly of claim 102,

wherein the third portion includes a plurality of section skip regions in one direction parallel to the winding direction.

104. The electrode assembly of claim 103,

wherein the plurality of section skip regions have a width gradually increasing or decreasing in one direction parallel to the winding direction.

105. The electrode assembly of claim 102,

wherein the height of the uncoated portion of the segment skip region is substantially the same as the height of the uncoated portion of the first portion or the uncoated portion of the second portion.

106. The electrode assembly of claim 102,

wherein the plurality of segments are located within a circumferential angle range preset based on a core center of the electrode assembly.

107. The electrode assembly of claim 102,

wherein the plurality of segments are located in at least two sector-shaped regions or polygonal regions disposed in a circumferential direction based on a core center of the electrode assembly.

108. The electrode assembly of claim 107,

wherein the scalloped region has a circumferential angle of 20 degrees or greater.

109. The electrode assembly according to claim 1,

wherein the second electrode includes a second active material portion coated with an active material layer in the winding direction and a second uncoated portion uncoated with an active material layer, at least a portion of the second uncoated portion itself being defined as an electrode tab, the second uncoated portion including a region divided into a plurality of sections that can be individually bent, and the plurality of sections being bent in a radial direction of the electrode assembly to form a bent surface region.

110. An electrode assembly in which a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode are wound based on a winding axis to define a core and an outer circumference,

the first uncoated portion includes a region divided into a plurality of sections individually bendable from the core of the electrode assembly toward the outer circumference,

The plurality of sections are bent in a radial direction of the electrode assembly to form a bent surface region, and

the inflection surface region includes an overlapping layer number uniformity region in which the number of overlapping layers of the segment is 10 or more and an overlapping layer number reduction region positioned adjacent to the overlapping layer number uniformity region in the radial direction such that the overlapping layer number of the segment gradually decreases away from the overlapping layer number uniformity region.

111. The electrode assembly of claim 110,

wherein the electrode assembly sequentially includes a segment skip region having no segments, a height variable region having a gradually increasing height in the radial direction of the electrode assembly, and a height uniform region having uniform height in the segments, and a starting radius of the overlapping layer number uniform region corresponds to a starting radius of the height variable region based on a core center of the electrode assembly.

112. The electrode assembly of claim 111,

wherein a region of the first uncoated portion adjacent to the core is not divided into sections and is disposed in the convolutions of the section skip zone.

113. The electrode assembly of claim 111,

114. The electrode assembly of claim 111,

115. The electrode assembly of claim 111,

116. The electrode assembly of claim 111,

117. The electrode assembly of claim 110,

wherein, in the region divided into the plurality of sections, at least one selected from the width of the section in the winding direction, the height in the winding axis direction, and the lower internal angle thereof is gradually increased in one direction parallel to the winding direction.

118. The electrode assembly of claim 110,

wherein a height of a region of the first uncoated portion adjacent to the core or the outer periphery of the electrode assembly is lower than a height of the plurality of sections.

119. The electrode assembly of claim 110,

wherein the plurality of sections are bent toward the core of the electrode assembly, and the core of the electrode assembly is not covered by the bent portion of a section positioned closest to the core of the electrode assembly by at least 90% or more of its diameter.

120. An electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are wound based on a winding axis to define a core and an outer circumference,

wherein the positive electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion uncoated with the active material layer,

at least a portion of the first uncoated portion itself serves as an electrode tab,

the first uncoated portion includes a plurality of sections individually bendable from the core of the electrode assembly toward the outer circumference,

the plurality of segments are bent in a radial direction of the electrode assembly and overlapped into a plurality of layers to form a bent surface region,

The inflection surface region includes an overlapping layer number uniformity region in which the overlapping layer number of the sections is uniform and a region of reduced overlapping layer number positioned adjacent to the overlapping layer number uniformity region in the radial direction such that the overlapping layer number of the sections gradually decreases away from the overlapping layer number uniformity region, and

in the region of uniform number of overlapping layers, the overlapping thickness of the segments is between 100 μm and 875 μm.

121. An electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are wound based on a winding axis to define a core and an outer circumference,

wherein the anode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion uncoated with the active material layer,

in the area of uniform number of overlapping layers, the overlapping thickness of the segments is between 50 μm and 700 μm.

122. A battery, the battery comprising:

an electrode assembly in which a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode are wound based on a winding axis to define a core and an outer circumference, wherein the first electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion uncoated with the active material layer, at least a portion of the first uncoated portion itself being defined as an electrode tab, the first uncoated portion including a first portion adjacent to the core of the electrode assembly, a second portion adjacent to the outer circumference of the electrode assembly, and a third portion interposed between the first portion and the second portion, and the first portion or the second portion has a height smaller than the third portion in the winding axis direction;

A battery case including an open end and a bottom opposite the open end, wherein the electrode assembly is received in a space between the open end and the bottom, and the battery case is electrically connected with any one of the first electrode and the second electrode to have a first polarity;

a sealing body configured to seal the open end of the battery case; and

a terminal electrically connected to the other of the first electrode and the second electrode to have a second polarity and configured to have a surface exposed to the outside.

123. The battery of claim 122,

wherein the second portion has a smaller height than the third portion in the winding axis direction, the battery case includes a beading portion press-fitted inward at a region adjacent to the open end, and an inner periphery of the beading portion facing a top edge of the electrode assembly is spaced apart from the second portion by a predetermined distance.

124. The battery of claim 123,

wherein a press-in depth D1 of the crimping portion and a distance D2 from the inner periphery of the battery case to a boundary between the second portion and the third portion satisfy a formula D1 ∈d2.

125. The battery of claim 123, the battery further comprising:

a current collector electrically coupled to the third portion; and

an insulator configured to cover the current collector and having an edge interposed and fixed between the inner periphery of the crimping portion and the current collector.

126. The battery of claim 125,

wherein the diameter of the current collector is smaller than the minimum inner diameter of the inner periphery of the beading portion, and the diameter of the current collector is equal to or larger than the outermost diameter of the third portion.

127. The battery of claim 125,

wherein the current collector is located at a position higher than the crimping portion in the winding axis direction.

128. The battery of claim 122,

wherein the sealing body includes a cap configured to seal the open end of the battery case, a gasket interposed between an edge of the cap and the open end of the battery case, and a crimping portion bent and extending into the battery case and configured to surround and fix the edge of the cap together with the gasket, and the terminal having the second polarity is the cap.

129. The battery of claim 122, the battery further comprising:

a first current collector electrically connected to the first uncoated portion,

wherein the terminal is a rivet terminal that is installed to be insulated from the battery case and electrically connected to the first current collector to have the second polarity in a penetration hole formed in the bottom of the battery case.

130. The battery of claim 129, the battery further comprising:

an insulator interposed between an inner surface of the bottom of the battery case and an upper surface of the first current collector to electrically insulate the inner surface of the bottom of the battery case from the first current collector.

131. The battery of claim 130,

wherein a thickness of the insulator corresponds to a distance between an inner surface of the bottom of the battery case and the upper surface of the first current collector, and the insulator is in close contact with the inner surface of the bottom of the battery case and the upper surface of the first current collector.

132. The battery of claim 130,

wherein the terminal includes a flat portion at a lower end thereof, the insulator has an opening for exposing the flat portion, and the flat portion is welded to the first current collector through the opening.

133. The battery of claim 122,

wherein the second electrode includes a second active material portion coated with an active material layer in the winding direction and a second uncoated portion uncoated with an active material layer, the second electrode having the first polarity, at least a portion of the second uncoated portion itself being defined as an electrode tab, and the battery further includes a second current collector electrically connected to the second uncoated portion and having an edge at least partially coupled to a side wall of the battery case.

134. The battery of claim 129,

wherein the second electrode includes a second active material portion coated with an active material layer in the winding direction and a second uncoated portion uncoated with an active material layer, the second electrode having the first polarity, at least a portion of the second uncoated portion itself being defined as an electrode tab, the battery further including a second current collector electrically connected to the second uncoated portion and having an edge at least partially coupled to a side wall of the battery case, and an outer diameter of the first current collector being equal to or greater than an outer diameter of the second current collector.

135. The battery of claim 134,

wherein the first and second current collectors are welded to the first and second uncoated portions, respectively, in a radial direction of the electrode assembly to form a welding pattern, and a length of the welding pattern of the first current collector is longer than a length of the welding pattern of the second current collector.

136. The battery of claim 135,

wherein the welding pattern of the first current collector and the welding pattern of the second current collector are located at substantially the same distance from a core center of the electrode assembly.

137. The battery of claim 133,

wherein the battery case includes a beading portion press-fitted inward at an inner wall adjacent to the open end, and the edge of the second current collector is electrically connected to the beading portion.

138. The battery of claim 137,

wherein a region of the second current collector that is in electrical contact with the second uncoated portion is further inward than an inner periphery of the crimping portion.

139. The battery of claim 137,

wherein, the battery includes: a cap having an edge supported by the beading portion and having no polarity; a gasket interposed between the edge of the cap and the open end of the battery case; and a crimping portion bent and extending into the open end of the battery case and configured to surround and fix the edge of the cap together with the gasket, and the edge of the second current collector is interposed and fixed between the crimping portion and the gasket by means of the crimping portion.

140. The battery of claim 137,

wherein the edge of the second current collector is welded to the beading portion.

141. The battery of claim 122,

wherein the third portion and optionally the second portion are divided into a plurality of sections that are individually bendable, and the area of the first uncoated portion divided into the plurality of sections includes a height-variable region in which the height of the sections is from a first height h ₁ Gradually change to the N-1 height h _N-1 N is a natural number of 2 or more and the height of the segment in the height uniformity region is maintained at an Nth height h _N ，h _N Is greater than h _N-1 。

142. The battery of claim 141,

wherein, N is a natural number from 2 to 30.

143. The battery of claim 141,

144. The battery of claim 141,

wherein when it includes a height h _k The initial radius of the convolutions of the segment of (a) is defined as r _k At least the core of the electrode assembly has a diameter at the same time 90% or more of the non-linear units are not located at the r _k The bend of the segment at which k is a natural number from 1 to N.

145. The battery of claim 141,

2mm≤h _k ≤r _k -α*r _c wherein α is 0.90 to 1.

146. The battery of claim 141,

wherein, when the convolution including the section is defined as r based on a radius of a core center of the electrode assembly and a width of the section in the winding direction is defined as D (r), D (r) satisfies the following formula:

1≤D(r)≤(2*π*r/360°)*45°。

147. the battery of claim 141,

wherein, in each of the plurality of sections, as the radius r of the winding turn where the section is located based on the core center of the electrode assembly increases, the width of the section in the winding direction gradually or stepwise increases or decreases.

148. The battery of claim 141,

wherein, in each of the plurality of sections, as the radius r of the winding turn where the section is located based on the core center of the electrode assembly increases, the height of the section in the winding direction gradually or stepwise increases and then gradually or stepwise decreases, or gradually or stepwise decreases and then gradually or stepwise increases.

149. The battery of claim 141,

wherein each of the plurality of sections has a geometry in which a width of a lower portion is greater than a width of an upper portion, and a lower internal angle θ of a section located in a convolution having a radius r based on the core of the electrode assembly falls within an angular range of the following formula:

150. The battery of claim 149,

wherein the lower internal angles of the plurality of sections increase individually or in groups in a range of 60 degrees to 85 degrees in one direction parallel to the winding direction.

151. The battery of claim 141,

h _max ≤W _foil -W _scrap,min -W _margin,min -W _gap

wherein W is _foil Is the width of the current collector foil before forming the segments; w (W) _scrap,min Is the width corresponding to the minimum cut scrap margin when forming a section by cutting the current collector foil; w (W) _margin,min Is a width corresponding to a minimum meandering margin of the diaphragm; w (W) _gap Is a width corresponding to an insulation gap between an end of the separator and an end of the second electrode facing the first electrode with the separator interposed therebetween.

152. The battery of claim 151,

153. The battery of claim 151,

154. The battery of claim 151,

wherein the minimum cutting waste margin is in the range of 1.5mm to 8 mm.

155. The battery of claim 151,

wherein the minimum meandering margin is in the range of 0mm to 1 mm.

156. The battery of claim 151,

wherein the minimum cutting waste margin is zero.

157. The battery of claim 151,

158. The battery of claim 122,

wherein the third portion and optionally the second portion are divided into a plurality of sections that can be individually bent, the electrode assembly sequentially includes a section skip region having no sections, a height variable region in which sections have a variable height, and a height uniform region in which sections have a uniform height in a radial direction based on a section along the winding axis direction, and the plurality of sections are disposed in the height variable region and the height uniform region, and the plurality of sections are bent in the radial direction of the electrode assembly to form a bent surface region.

159. The battery of claim 158,

160. The battery of claim 158,

161. The battery of claim 158,

162. The battery of claim 158,

163. The battery of claim 158,

164. The battery of claim 158,

165. The battery of claim 141,

166. The battery of claim 165,

167. The battery of claim 165,

168. The battery of claim 158,

wherein, when the number of sections intersecting with a virtual line parallel to the winding axis direction at any radial position of the inflection surface region based on the core center of the electrode assembly is defined as the number of overlapping layers of sections at the corresponding radial position, the inflection surface region includes an overlapping layer number uniform region in which the overlapping layer number of sections is uniform from the core toward the outer circumference and an overlapping layer number reduction region positioned adjacent to the overlapping layer number uniform region such that the overlapping layer number of sections gradually decreases away from the overlapping layer number uniform region.

169. The battery of claim 168,

wherein the number of overlapping layers of the section is 10 or more in the overlapping layer number uniform region.

170. The battery of claim 168,

wherein the number of overlapping layers of the section is 10 to 35 in the overlapping layer number uniform region.

171. The battery of claim 168,

wherein a starting radius of the overlapping layer number uniform region corresponds to a starting radius of the height variable region based on the core center of the electrode assembly.

172. The battery of claim 168,

173. The battery of claim 168,

174. The battery of claim 168,

wherein the battery further comprises a current collector welded to the overlap layer number uniformity region such that at least a portion of the welded region of the current collector overlaps the overlap layer number uniformity region, and

Wherein the first electrode is a positive electrode and the overlapping layer of the segments in the welding zone has a thickness in the range of 100 μm to 875 μm.

175. The battery of claim 168,

176. The battery of claim 168,

wherein the first electrode is a negative electrode and the overlapping layer of the segments in the welding zone has a thickness in the range of 50 μm to 700 μm.

177. The battery of claim 122,

wherein the third portion and optionally the second portion are divided into a plurality of sections that can be individually bent, a cutting groove is interposed between the sections adjacent to each other in the winding direction, and a lower portion of the cutting groove includes a bottom portion and a rounded portion for connecting both ends of the bottom portion to side portions of the sections on both sides of the cutting groove.

178. The battery of claim 177,

179. The battery of claim 177,

wherein the rounded portion has a radius of curvature of 0.01mm to 0.05 mm.

180. The battery of claim 177,

wherein the bottom is flat.

181. The battery of claim 177,

182. The battery of claim 177,

wherein the plurality of sections are made of aluminum foil, and are defined as a separation pitch of 0.05mm to 1.00mm of a space between two points where a line extending from the side portions of the two sections located at both sides of the cutting groove intersects a line extending from the lower end of the cutting groove.

183. The battery of claim 177,

184. The battery of claim 183,

185. The battery of claim 177,

186. The battery of claim 177,

187. The battery of claim 186,

188. The battery of claim 186,

189. The battery of claim 188,

190. The battery of claim 186,

191. The battery of claim 190,

wherein the insulating coating layer is exposed outside the separator.

192. The battery of claim 186,

193. The battery of claim 192,

194. The battery of claim 168, the battery further comprising:

a current collector welded to the inflection surface region,

195. The battery of claim 194,

196. The battery of claim 194,

wherein an edge of the current collector is disposed on the inflection surface region to cover an end of the inflection portion of the outermost section in the radial direction of the electrode assembly and welded to the inflection surface region.

197. The battery of claim 194,

wherein the welding strength of the current collector and the welding area is 2kgf/cm ² The above.

198. The battery of claim 194,

wherein the welding strength of the current collector and the welding area is 4kgf/cm ² The above.

199. The battery of claim 122,

wherein the first uncoated portion is made of a metal foil, and the metal foil has an elongation of 1.5% to 3.0% and a tensile strength of 25kgf/mm ² To 35kgf/mm ² 。

200. The battery of claim 199,

wherein the metal foil is aluminum foil.

201. The battery of claim 199,

wherein the first electrode has a warp length of less than 20 mm.

202. The battery of claim 122,

203. A battery, the battery comprising:

an electrode assembly in which a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode are wound based on a winding axis to define a core and an outer circumference, wherein the first electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion uncoated with an active material layer, the first uncoated portion includes a region divided into a plurality of sections individually bendable from the core of the electrode assembly toward the outer circumference, the plurality of sections are bent in a radial direction of the electrode assembly to form a bending surface region, and the bending surface region includes an overlapping layer number uniform region in which the number of overlapping layers of the sections is 10 or more, and an overlapping layer number reduction region positioned adjacent to the overlapping layer number uniform region in the radial direction such that the number of overlapping layers of the sections gradually decreases away from the overlapping layer number uniform region;

A sealing body configured to seal the open end of the battery case; and

204. A battery, the battery comprising:

an electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are wound based on a winding axis to define a core and an outer circumference, wherein the positive electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion uncoated with an active material layer, at least a portion of the first uncoated portion itself serving as an electrode tab, the first uncoated portion including a plurality of sections individually bendable from the core toward the outer circumference of the electrode assembly, the plurality of sections being bent in a radial direction of the electrode assembly and overlapping into a plurality of layers to form a bending surface region, the bending surface region including an overlapping layer number uniform region in which an overlapping layer number of the sections is uniform and a overlapping layer number uniform region positioned adjacent to the overlapping layer number uniform region in the radial direction such that the amount of the sections is gradually reduced away from the overlapping layer number uniform region and a number of overlapping layers 87m is gradually reduced between the overlapping layer number uniform region and a thickness of the sections of 100 μm;

a sealing body configured to seal the open end of the battery case; and

205. The battery of claim 204,

wherein the overlapping layer of segments in the weld zone has a thickness in the range of 100 μm to 875 μm.

206. A battery, the battery comprising:

an electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are wound based on a winding axis to define a core and an outer circumference, wherein the negative electrode includes a first active material portion coated with an active material layer in a winding direction and a first uncoated portion not coated with an active material layer, at least a portion of the first uncoated portion itself serving as an electrode tab, the first uncoated portion including a plurality of sections individually bendable from the core of the electrode assembly toward the outer circumference, the plurality of sections being bent in a radial direction of the electrode assembly and overlapping into a plurality of layers to form a bending surface region including an overlapping layer number uniform region in which an overlapping amount of the sections is uniform and an overlapping layer number uniform region positioned adjacent to the overlapping layer number uniform region in the radial direction such that the number of layers of the sections is gradually reduced away from the overlapping uniform region and a number of layers of the overlapping layer is gradually reduced to 700 μm in the overlapping layer number uniform region between the sections;

a sealing body configured to seal the open end of the battery case; and

207. The battery of claim 206,

wherein the overlapping layer of segments in the weld zone has a thickness in the range of 50 μm to 700 μm.

208. A battery pack comprising a plurality of cells according to any one of claims 122 to 207.

209. The battery pack of claim 208,

Wherein the ratio of the diameter to the height of the battery is greater than 0.4.

210. The battery pack of claim 209,

wherein the battery has a form factor of 46110, 4875, 48110, 4880, or 4680.

211. The battery pack of claim 208,

wherein the battery has a resistance of less than 4 milliohms.

212. The battery pack of claim 208,

wherein the plurality of cells are arranged in a predetermined number of columns such that the terminals of each cell and the outer surface of the bottom of the cell housing of each cell face upward.

213. The battery pack of claim 212, the battery pack further comprising:

a plurality of bus bars configured to connect the plurality of batteries in series and parallel,

wherein the plurality of bus bars are disposed at upper portions of the plurality of batteries, and

each of the bus bars includes: a body portion configured to extend between terminals of adjacent cells; a plurality of first bus bar terminals configured to extend from one side of the body portion and to be electrically coupled to terminals of a battery located on one side; and a plurality of second bus bar terminals configured to extend from the other side of the body portion and to be electrically coupled to an outer surface of the bottom portion of the battery case of the battery located at the other side.

214. A vehicle comprising a battery pack according to any one of claims 208 to 213.