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

Abstract

Disclosed are an electrode assembly, a battery, and a battery pack and a vehicle including the battery. One end of the electrode assembly includes: a plurality of segment alignment units in which a plurality of segment groups are aligned in a radial direction; and an electrolyte impregnation portion in which end portions of an active material portion between segment alignment units adjacent in a circumferential direction are exposed between wound turns of a separator, wherein segments included in the segment alignment units form a bent surface region, and an end portion of the separator can be spaced apart from a reference line by a distance of not more than 30% of a minimum height of segments forming the bent surface region, the reference line extending in a wound axis direction along a position corresponding to a cutting groove between segments.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2021-0160823, filed in Korea on November 19, 2021, and Korean Patent Application No. 10-2022-0005393, filed in Korea on January 13, 2022, the disclosures of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to an electrode assembly, a battery, a battery pack including the battery, and a vehicle. Background Technology

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

[0004] Because these secondary batteries have the primary advantage of significantly reducing fossil fuel use and the secondary advantage of not producing byproducts from energy use, they are attracting attention as a new energy source for improving eco-friendliness and energy efficiency.

[0005] Currently, widely used secondary battery types in this field include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of a single secondary battery (i.e., a single cell) is approximately 2.5V to 4.5V. Therefore, when a higher output voltage is required, multiple batteries can be connected in series to form a battery pack. Furthermore, multiple batteries can be connected in parallel to form a battery pack, depending on the required charge / discharge capacity. Therefore, the number of batteries included in a battery pack and the form of electrical connection can be set differently depending on the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, cylindrical, rectangular, and pouch-type batteries are known as unitary secondary batteries. In the case of cylindrical batteries, a separator, serving as an insulator, is inserted between the positive and negative electrodes, and these separators are wound to form an electrode assembly in the form of a wound core, which is inserted into the battery casing to configure the battery. The battery casing is referred to in the art as a battery can. Furthermore, a strip electrode connector can be connected to the uncoated portion of each of the positive and negative electrodes, and the electrode connector electrically connects the electrode assembly to the exposed electrode terminals. For reference, the positive terminal is the cap of a seal that seals the opening of the battery casing, and the negative terminal is the battery casing itself. However, according to conventional cylindrical batteries with this structure, the current collection efficiency is poor due to high resistance and significant heat generation because the current is concentrated in the strip electrode connector connected to the uncoated portion of the positive electrode and / or the uncoated portion of the negative electrode.

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

[0008] To address this issue, a cylindrical battery (so-called a connectorless cylindrical battery) is provided, wherein the uncoated portions of the positive and negative electrodes are designed to be positioned at the top and bottom of a wound electrode assembly, respectively, and the current collector is welded to the uncoated portions to improve current collection efficiency.

[0009] Figures 1 to 3 This is a diagram illustrating the process of manufacturing a connectorless cylindrical battery. Figure 1 The structure of the electrode is shown. Figure 2 The process of winding the electrode is shown, and Figure 3 The process of welding a current collector to a bent surface of an uncoated portion is shown.

[0010] refer to Figures 1 to 3 The positive electrode 10 and the negative electrode 11 have a structure in which the current collector 20 is coated with an active material 21 and includes an uncoated portion 22 along a long side in the winding direction X. The long side refers to the relatively long side in the direction parallel to the x-axis.

[0011] like Figure 2 As shown, electrode assembly A is manufactured by sequentially stacking the positive electrode 10 and the 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.

[0012] After the winding process, the uncoated portion 10a of the positive electrode 10 and the uncoated portion 11a of the negative electrode 11 are bent toward the core. Thereafter, current collectors 30 and 31 are welded and connected to the uncoated portions 10a and 11a, respectively.

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

[0014] In a seamless cylindrical battery, in order to improve the welding characteristics between the uncoated portions 10a and 11a and the current collectors 30 and 31, it is necessary to apply strong pressure to the welding area of ​​the uncoated portions 10a and 11a to make the uncoated portions 10a and 11a bend as flat as possible.

[0015] However, when the welding area of ​​the uncoated portions 10a and 11a is bent, the shape of the uncoated portions 10a and 11a may be irregularly twisted and deformed. In this case, the deformed portion may come into contact with an electrode of opposite polarity, resulting in an internal short circuit or micro-cracks in the uncoated portions 10a and 11a. Furthermore, when the uncoated portion 32 of the core of the adjacent 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, problems arise during the electrolyte injection process. That is, the cavity 33 in the core of the electrode assembly A serves as a channel for injecting electrolyte. However, if the corresponding channel is blocked, it is difficult to inject electrolyte. Furthermore, 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 tear.

[0016] Furthermore, the bends of the welding current collectors 30 and 31 in the uncoated portions 10a and 11a should overlap in multiple layers, and there should be no empty spaces (gaps). In this way, sufficient welding strength can be obtained, and even with the latest technologies such as laser welding, it can be prevented that the laser penetrates into the electrode assembly A and melts the diaphragm or active material.

[0017] Meanwhile, the bent surface area formed by bending the uncoated portions 10a and 11a of electrode assembly A has almost no gap in the winding axis direction through which the electrolyte can pass. This is because during the bending of the uncoated portions 10a and 11a, most of the gap between the winding turns that immediately follow the winding disappears.

[0018] Therefore, the structure of bending the entire end of the uncoated portions 10a and 11a can increase the electrolyte immersion time.

[0019] Furthermore, in conventional seamless cylindrical batteries, the uncoated positive electrode portion 10a is integrally formed on the upper part of the electrode assembly A. Therefore, when the outer periphery at the top of the battery casing is press-fitted inward to form a rolled edge, the upper edge region 34 of the electrode assembly A is pressed by the battery casing. This pressing may cause localized deformation of the electrode assembly A, potentially leading to an internal short circuit due to tearing of the separator 12. If an internal short circuit occurs, it may cause the battery to overheat or explode. Summary of the Invention

[0020] Technical issues

[0021] The present invention aims to solve the problems of the prior art, and therefore aims to provide an electrode assembly with an uncoated portion structure, which is improved to reduce the stress applied to the uncoated portion when the uncoated portion exposed at both ends of the electrode assembly is bent.

[0022] This disclosure also relates to providing an electrode assembly in which the electrolyte injection channel is not blocked even if the uncoated portion is bent.

[0023] This disclosure also relates to providing an electrode assembly having a structure that prevents the top edge of the electrode assembly from contacting the inner surface of the battery housing when a crimp is formed on the top of the battery housing.

[0024] This disclosure also relates to an electrode assembly with improved characteristics of the welding area by applying a segment structure to the uncoated portion of the electrode and optimizing the dimensions (width, height, and spacing) of the segments to sufficiently increase the number of segments stacked in the area used as the welding target area.

[0025] This disclosure also relates to an electrode assembly with improved energy density and reduced resistance by applying a structure in which a current collector is welded to a curved surface region formed by bending a segment through a wide area.

[0026] This disclosure also relates to providing an electrode assembly having a structure to which a current collector can be stably welded.

[0027] This disclosure also relates to providing electrode assemblies with improved electrolyte impregnation characteristics.

[0028] This disclosure also relates to providing a battery with an improved design including terminals and current collectors, which allows electrical wiring to be performed in the upper portion.

[0029] This disclosure also relates to providing a battery including an electrode assembly with an improved structure, a battery pack including the battery, and a vehicle including the battery pack.

[0030] The technical objectives to be addressed by this invention are not limited thereto, and those skilled in the art will clearly understand from the following disclosure that other objectives not mentioned herein exist.

[0031] Technical solution

[0032] In one aspect of this disclosure, an electrode assembly is provided in which a first electrode, a second electrode, and a diaphragm inserted between the first electrode and the second electrode are wound based on a winding axis to define a core and an outer periphery, wherein at least one of the first electrode and the second electrode may include an active material portion coated with an active material layer along the winding direction and an uncoated portion without an active material layer.

[0033] At least a portion of the uncoated portion can itself be used as an electrode connector.

[0034] The uncoated portion may include an insulating layer formed along the winding direction at the base end, which serves as the boundary region with the active material layer.

[0035] The uncoated portion may include an area divided into multiple independently bendable segments by means of multiple cutting grooves arranged along the winding direction.

[0036] The gap between the bottom of the cutting groove and the insulation layer can be varied along the winding direction.

[0037] When a segment is bent, the insulation layer supports the base end of the uncoated portion to prevent deformation of the base end. Because the stiffness of the base end is reinforced, the segment can be bent precisely based on its lower end when bent.

[0038] At least a portion of the insulating layer may be exposed to the outside of the diaphragm. When the segment bends, short circuits between adjacent electrodes with different polarities can be prevented by covering an area of ​​the uncoated portion with the insulating layer that protrudes further outward than the diaphragm.

[0039] The insulating layer formed on the uncoated portion can be thinner than the active material layer, thus allowing it to be spaced apart from the diaphragm. That is, the active material layer can contact the diaphragm, but a gap can exist between the insulating layer on the uncoated portion and the diaphragm. Therefore, even if the base end of the uncoated portion deforms slightly due to bending force during segmental bending, the insulating layer can minimize the impact of the deformation on the diaphragm.

[0040] Within a predetermined region of the electrode, the gap can be increased or decreased more than in the remaining region.

[0041] In the predetermined region of the electrode, the gap can be uniform along a direction parallel to the winding direction, or it can gradually or progressively increase along a direction parallel to the winding direction.

[0042] The gap can be from 0.2mm to 4mm.

[0043] The segment can have a geometry in which the width in the winding direction decreases from bottom to top, and the lower inner angle can gradually or progressively increase from the core toward the periphery.

[0044] Multiple segments can include groups of segments that have the same lower interior angle between adjacent segments in the winding direction. If segments are managed in groups, segments can be easily designed and manufactured.

[0045] The lower interior angle (θ) of each segment belonging to any segment group can be equal to or greater than the lower interior angle of each segment belonging to the segment group closer to the core. The curvature of the core-type electrode assembly decreases towards the outer periphery. Therefore, the gap between adjacent segments in the circumferential direction of the electrode assembly can be minimized by increasing the lower interior angle of the segments closer to the outer periphery, which helps to ensure the weld strength of the current collector, as explained later.

[0046] Multiple segments may include multiple segment groups that are identical in terms of a first element selected from the lower interior angle (θ) of the segment, the axial height (H) of the segment, the width (D) of the segment in the winding direction, the shape of the segment, the height of the bottom of the cutting groove between two segments, and the separation distance (P) between two segments.

[0047] Here, the first element can be different between segments belonging to different segment groups.

[0048] When the first element is the lower interior angle of a segment, the lower interior angle of a segment belonging to any segment group can be greater than the lower interior angle of a segment belonging to a segment group closer to the core.

[0049] When the first element is the height of the segment in the axial direction (the winding axis of the core shape), the height of a segment belonging to one segment group can be higher than the height of a segment belonging to a segment group closer to the core. Then, when the segment located at the outer periphery is bent, the number of overlapping segments with the segment located closer to the core can be further increased, and the number of overlapping segments of the bent segments remains uniform in the radial direction of the electrode assembly, thereby fixing a bent surface area suitable for welding current collectors and easy to weld.

[0050] When the first element is the width of the segment in the winding direction, the width of a segment belonging to any segment group in the winding direction can be greater than the width of a segment belonging to a segment group closer to the core in the winding direction. The radius of curvature of the electrode assembly wound in the form of a core increases towards the outer periphery. Therefore, it is desirable to gradually increase the width in the winding direction so that the segments can bend smoothly.

[0051] Segments belonging to the same segment group can be identical not only in terms of the first element, but also in terms of the second element, which is selected to not overlap with the first element in terms of the lower inner angle of the segment, the axial height of the segment, the width of the segment in the winding direction, the shape of the segment, the height of the bottom of the cutting groove between the two segments, and the separation distance between the two segments.

[0052] For example, segments belonging to the same segment group can be substantially the same in terms of the lower interior angle of the segment, the axial height of the segment, the width of the segment in the winding direction, the shape of the segment, the height of the bottom of the cutting groove between the two segments, and the separation distance between the two segments.

[0053] Segments belonging to different segment groups can differ from each other in terms of the second element. For example, segments belonging to different segment groups can differ from each other in terms of the lower interior angle of the segment, the axial height of the segment, and the width of the segment in the winding direction.

[0054] Multiple segment groups can have a group separation interval Db that is greater than the separation distance between segments in the same segment group.

[0055] The group separation interval Db can provide an electrolyte impregnation portion that is not covered by segments bent on a surface perpendicular to the axial direction of the electrode assembly. The area corresponding to the electrolyte impregnation portion is not welded to the current collector, which can improve the impregnation performance of the electrolyte.

[0056] The segment groups separated by the group separation intervals can be arranged radially based on the center of the electrode assembly to form multiple segment alignment sections. Furthermore, an electrolyte impregnation section formed by the area around the separation sections between the groups can be provided radially based on the center of the electrode assembly. Therefore, a channel for electrolyte impregnation can be ensured, while reliably guaranteeing the welding area with the current collector.

[0057] The segments included in the segment alignment section can be bent radially toward the core of the electrode assembly to form bent surface areas in multiple separation regions.

[0058] The circumferential angle between adjacent segment alignments (or bent surface areas) in the circumferential direction can be approximately 30, 40, 45, 60, 72, 90, 120, or 180 degrees. When the angle measurement line is defined as a line connecting the geometric center of each segment alignment (or bent surface area) from the core center of the electrode assembly, the angle is the angle between adjacent angle measurement lines in the circumferential direction. The geometric center is the geometric center of the figure formed approximately by the edges of the segment alignment (or bent surface area) when viewed in the axial direction. The geometric center can be the centroid of the figure.

[0059] The current collector can be welded to multiple bent surface areas. The number of weld positions can be 12, 9, 8, 6, 5, 4, 3 or 2 at equal intervals in the circumferential direction.

[0060] The width of at least one of the group separation intervals and each group of segments in the winding direction can gradually or progressively increase from the core toward the outer periphery. Therefore, the bent surface area formed by bending the unsegmented surfaces of the segments and / or electrode assemblies along the axial direction can form a fan shape that is generally without a central region.

[0061] The uncoated portion may include a first portion adjacent to the core of the electrode assembly, a second portion adjacent to the outer peripheral surface of the electrode assembly, and a third portion inserted between the first and second portions.

[0062] The third part may include segments.

[0063] The second part may not have a segmental structure.

[0064] Preferably, at least one of the first and second portions may have a relatively smaller height than the third portion in the direction of the winding axis.

[0065] The first and third parts can be directly connected without connecting their respective regions, or connected by means of regions that connect them.

[0066] The third and second parts can be directly connected without connecting areas, or connected by means of areas that connect them.

[0067] In the winding direction, the first section can begin from the end near the core.

[0068] In the winding direction, the length of the third part can be longer than the length of the first and second parts.

[0069] In the winding direction, the second portion may include at least one last turn exposed on the outermost side of the electrode assembly.

[0070] The height of the uncoated portion in the predetermined area can represent the average height of the corresponding area or the maximum height within the corresponding area.

[0071] The height of the first part can be constant along the winding direction. That is, the first part may not include segments.

[0072] In at least a portion of the third part, the height of the segment can increase from the core toward the periphery.

[0073] At this point, the height of the segment can be gradually increased.

[0074] Furthermore, as the height gradually increases, the length (width) of the region corresponding to each height in the winding direction can also gradually increase.

[0075] The second part may also include segments.

[0076] This segment can be bent in the radial direction of the electrode assembly.

[0077] This segment can be bent toward the core (i.e., in the centripetal direction) along the central axis of the electrode assembly.

[0078] The first part does not have segments, so it does not need to be bent.

[0079] The last turn may not include any segments. Furthermore, the last turn may have a lower height than the third section. When forming a wound-core electrode assembly, manipulating the assembly can be cumbersome if there are segments to be bent in the last turn, as accidental deformation of the segments must be prevented. Removing the segments from the last turn reduces this cumbersome work.

[0080] The center of the electrode assembly may have a hollow portion extending axially, and the bent segments may not cover the hollow portion in the direction toward the core.

[0081] The third part of the bend can overlap in the axial direction.

[0082] The third and second bends can overlap in the axial direction.

[0083] Each of the multiple segments can have a trapezoidal shape.

[0084] In one respect, in at least a portion of the third part, the height in the direction of the winding axis can gradually increase from the core toward the outer periphery.

[0085] On the other hand, at least a portion of the third part can be divided into multiple segments.

[0086] The uncoated portion can be separated by a cutting groove extending from the axial end of the winding axis to the inner side in the axial direction (from the edge of the electrode assembly in the axial direction to the center in the axial direction). The shape of the cutting groove is determined by the shape of the side surfaces of the segments located on both sides of the cutting groove. The cutting line can also be regarded as a cutting groove when the uncoated portion is simply cut by grooving it without removing at least a portion of the uncoated portion from the notch.

[0087] On the other hand, each of the multiple segments can have a rectangular, trapezoidal, triangular, parallelogram, semicircular, or semielliptical structure.

[0088] In one implementation, each of the plurality of segments is trapezoidal, and the plurality of segments can be configured such that the lower interior angle of the trapezoid increases individually or in groups from the core toward the periphery.

[0089] With the help of segments, the axial extension length of the uncoated portion can vary along the winding direction. For ease of explanation, if the axial extension length of the uncoated portion at a predetermined position in the winding direction (the distance from the axial direction to the front end) is simply referred to as height, it is clear that the meaning that the height of the uncoated portion at the first position in the winding direction is higher than the height of the uncoated portion at the second position in the winding direction can be understood.

[0090] When explaining the height of the uncoated portion in the embodiment, the relative value of the height of the uncoated portion measured at different positions in the winding direction is more meaningful than the absolute value of the height of the uncoated portion. Therefore, when measuring the height of the uncoated portion, the rule of the line (zero point) used as the standard for height measurement will be omitted.

[0091] The height of the uncoated portion can differ between the portion corresponding to the top of the segment, the portion corresponding to the cutting groove to which the segment is to be formed, and the portion corresponding to the bottom of the cutting groove. That is, even if the shape and size of the segment are the same as the shape and size of the cutting groove, the height of the uncoated portion measured axially can vary depending on the measurement position determined along the winding direction. For example, it is obvious that the height of the uncoated portion at the position in the winding direction corresponding to the top of the segment is approximately higher than the height of the uncoated portion at the position in the winding direction corresponding to the bottom of the cutting groove.

[0092] Furthermore, the top height of each segment can be different, the shape of the cutting groove can be different, and the bottom height of the cutting groove can also be different. That is, since the shape and size of the segments and the shape and size of the cutting groove can vary, the height of the uncoated portion measured along the axial direction can be changed according to the measurement position determined along the winding direction.

[0093] Meanwhile, the height of a segment can be defined as the axial distance (H) from the bottom of the cutting groove defining the corresponding segment to the front end of the corresponding segment. If the heights of the bottoms of the cutting grooves on both sides are different based on the corresponding segment, the height of the corresponding segment can be defined as the axial distance from the average height point of the bottoms of the cutting grooves on both sides to the front end of the segment.

[0094] Preferably, at least one of the height in the winding axis direction and the width in the winding direction of the multiple segments can be gradually increased from the core toward the outer periphery, either individually or in groups.

[0095] Preferably, each of the plurality of segments can satisfy at least one of the following conditions: a width condition of 1 mm to 11 mm in the winding direction; a height condition of 2 mm to 10 mm in the winding axis direction; and a separation spacing condition of 0.05 mm to 1 mm in the winding direction.

[0096] Preferably, there may be a gap between the bottom of the cutting groove of the segment and the active material layer, but the gap may be from 0.2 mm to 4 mm.

[0097] Preferably, multiple segments extend from the core toward the outer periphery to form multiple segment groups, and segments belonging to the same segment group may have the same width in the winding direction, height in the winding axis direction, and spacing in the winding direction.

[0098] Preferably, when the widths of three consecutive adjacent segments in the radial direction of the electrode assembly are W1, W2 and W3 respectively in the winding direction, it may include a combination of segments in which W3 / W2 is less than W2 / W1.

[0099] Preferably, in segments belonging to the same segment group, at least one of the width in the winding direction, the height in the winding axis direction, and the separation distance in the winding direction can gradually increase from the core towards the outer periphery.

[0100] In one embodiment, at least a portion of the multiple segment groups may be located at the same winding turn of the electrode assembly.

[0101] In another embodiment, the first or second portion may not have a segmental structure with an uncoated portion.

[0102] The segment can be bent in the radial direction.

[0103] All segments in a multi-segment structure can be bent.

[0104] A portion of a multi-segment may remain straight.

[0105] Preferably, multiple segments can overlap in several layers along the winding axis while bending toward the core.

[0106] Preferably, a cavity can be provided in the core of the electrode assembly, and the cavity can be opened without being blocked by multiple segments bending toward the core.

[0107] Therefore, the radial length (R) of the first part and the bending length (H) of the innermost segment of the third part can satisfy the relationship H≤R.

[0108] In one implementation, the height of the second part can decrease gradually or progressively from the core toward the outer periphery.

[0109] In one embodiment, the second portion is divided into multiple segments, and in at least one aspect of the width in the winding direction, the height in the winding axis direction, and the separation spacing in the winding direction, the multiple segments included in the second portion may be larger than the multiple segments included in the third portion.

[0110] If an imaginary straight line drawn along the winding direction (circumferential direction) corresponding to the height of the bottom of the cutting groove is called the baseline DL, then the baseline can be a straight line parallel to the winding direction X of the uncoated portion.

[0111] The baseline can be set between two adjacent segments at a position corresponding to the bottom of the cutting groove to form segments.

[0112] The heights corresponding to the bottoms of multiple cutting grooves can correspond to each other along the winding axis. In this case, the position of the baseline can be defined as the position corresponding to the bottom of the cutting groove.

[0113] The bottom heights of multiple cutting grooves can be different from each other.

[0114] If the majority of the bottom of the cut groove (e.g., 50% or more) is located at a specific height and only some cut grooves have bottoms at heights different from this specific height, then the position of the baseline can be determined to correspond to the height of that specific height. That is, in this case, the baseline can be determined based on the height of the bottom of the cut groove that occupies the longest length in the winding direction. For example, if approximately two-thirds of the total length of the cut groove's bottom in the winding direction has a first height, and the bottom of the cut groove corresponding to the remaining one-third of the total length of the cut groove's bottom in the winding direction has a height different from the first height, then the baseline can be defined as the position corresponding to the first height.

[0115] If the height of the bottom of the cut groove is not concentrated at a specific height (when the proportion of the uncoated portion forming the cut groove with the most frequent height is less than 50% of the total electrode length), the baseline can be set at the average height of the bottom of the cut groove. For example, when measuring the height based on the boundary point between the active material layer and the uncoated portion, if the length of the uncoated portion where the bottom height of the cut groove is 2 mm occupies 30% of the total electrode length, the length of the uncoated portion where the bottom height of the cut groove is 3 mm occupies 30% of the total electrode length in the winding direction, and the length of the uncoated portion where the bottom height of the cut groove is 4 mm occupies 40% of the total electrode length in the winding direction, then the baseline can be located at a height of 3.1 mm, which is 2*0.3+3*0.3+4*0.4.

[0116] The position of the end SL of the diaphragm in the axial direction Y can be adjusted relative to the baseline DL.

[0117] The segment with the smallest height among multiple segments is called the smallest segment.

[0118] When determining the segment with the minimum height, unbent segments can be excluded. That is, the minimum segment can be the segment with the minimum height among the bent segments included in the bent surface area. The bent surface area refers to the region where the segments on the end face of the electrode assembly are bent in the radial direction and overlap into multiple layers along the winding axis.

[0119] The smallest segment can be determined within the bent segments.

[0120] If the height of the segment is less than 2 mm, there is a possibility that the segment may not be able to bend smoothly due to interference between the diaphragm and the segment.

[0121] Therefore, the minimum segment can be determined in segments with a height of 2 mm or greater.

[0122] If the segment height is less than 3 mm, the segment may bend undesirably in the expected direction or may take shape in an undesirable direction during the bending process.

[0123] Therefore, the minimum segment can be determined in segments with a height of 3 mm or greater.

[0124] If the height of a segment is less than 4 mm, welding between segments and / or welding between the current collector and the segment may not be fully performed.

[0125] Therefore, the minimum segment can be determined in segments with a height of 4 mm or greater.

[0126] If the segment height is 5mm or greater, bending can be performed reliably during the bending process, even taking manufacturing errors into account.

[0127] Therefore, the minimum segment can be determined in segments with a height of 5 mm or greater.

[0128] The end SL of the diaphragm in the width direction may be located in the outward direction of the electrode assembly within 30% of the height Ha of the minimum segment based on the reference line DL, or the end SL of the diaphragm in the width direction may be located in the inward direction of the electrode assembly within 30% of the height of the minimum segment based on the reference line DL.

[0129] That is, the position of the end of the diaphragm in the width direction can be within the range of DL±0.3Ha.

[0130] The end SL of the diaphragm in the width direction can be located in the outward direction of the electrode assembly within 1.5 mm based on the reference line DL, or the end SL of the diaphragm in the width direction can be located in the inward direction of the electrode assembly within 1.5 mm based on the reference line DL.

[0131] That is, the position of the end SL of the diaphragm in the width direction can be within the range of DL±1.5mm.

[0132] The end SL of the diaphragm in the width direction can be located in the outward direction of the electrode assembly within 1.2 mm based on the reference line DL, or the end SL of the diaphragm in the width direction can be located in the inward direction of the electrode assembly within 1.2 mm based on the reference line DL.

[0133] That is, the position of the end SL of the diaphragm in the width direction can be within the range of DL±1.2mm.

[0134] The end SL of the diaphragm in the width direction can be located in the outward direction of the electrode assembly within 0.9 mm based on the reference line DL, or the end SL of the diaphragm in the width direction can be located in the inward direction of the electrode assembly within 0.9 mm based on the reference line DL.

[0135] That is, the position of the end SL of the diaphragm in the width direction can be within the range of DL±0.9mm.

[0136] The end SL of the diaphragm in the width direction can be located in the outward direction of the electrode assembly within 0.6 mm based on the reference line DL, or the end SL of the diaphragm in the width direction can be located in the inward direction of the electrode assembly within 0.6 mm based on the reference line DL.

[0137] That is, the position of the end SL of the diaphragm in the width direction can be within the range of DL±0.6mm.

[0138] The position of the end SL of the diaphragm in the width direction can be within the range of DL±1.5mm and DL±0.3Ha.

[0139] The position of the end SL of the diaphragm in the width direction can be within the range of DL±1.2mm and DL±0.3Ha.

[0140] The position of the end SL of the diaphragm in the width direction can be within the range of DL±0.9mm and DL±0.3Ha.

[0141] The position of the end SL of the diaphragm in the width direction can be within the range of DL±0.6mm and DL±0.3Ha.

[0142] The membrane may include: a porous polymer substrate; and a porous coating layer located on the surface of the porous polymer substrate and comprising inorganic particles and a binder polymer.

[0143] The porous coating can be located on both surfaces of the porous polymer substrate.

[0144] Multiple segments can have a predetermined separation spacing.

[0145] The separation spacing can be defined by the distance between the bottom corners of two adjacent segments.

[0146] The separation gap can be 0.5 mm or greater. When the separation gap is smaller than this, stress concentration occurs, which may cause cracks to appear at the bottom of the corresponding cut groove during processing, winding, or bending.

[0147] The corners at the bottom of the two segments can be directly connected. That is, the bottom of the cutting groove can have a flat, linear shape extending along the winding direction X.

[0148] Rounded reinforcement sections can be added to corners.

[0149] The radius (r) of the rounded reinforcement can be greater than or equal to 0.02 mm. If the corresponding radius is 0.02 mm or greater, the effect on stress distribution can be clearly observed.

[0150] The radius of the rounded reinforcement section can be 0.1 mm or smaller. If the radius exceeds 0.1 mm, the effect of stress distribution no longer increases, and the space around the bottom of the cut groove decreases, which may degrade the impregnation characteristics of the electrolyte.

[0151] The separation gap can be less than 1 mm. If the separation gap exceeds 1 mm, the impregnation characteristics will not increase, but gaps may be generated between the bent segments, which may increase the possibility that the current collector is not properly welded.

[0152] The separation gap can be determined relative to the width of adjacent segments measured in the winding direction.

[0153] For example, as the width of a segment increases in the winding direction, the separation distance between segments may also tend to increase. Therefore, the impregnation properties of the electrolyte can be uniform.

[0154] The width of the segment in the winding direction can show a trend of gradually increasing from the core of the electrode assembly toward the outer periphery.

[0155] The width of the segment in the winding direction can gradually or progressively increase from the core of the electrode assembly toward the outer periphery.

[0156] Therefore, the separation distance can also gradually or progressively increase from the core of the electrode assembly toward the outer periphery.

[0157] In one aspect of this disclosure, a battery may be provided, comprising: an electrode assembly in which a first electrode, a second electrode, and a separator between the first and second electrodes are wound based on a winding axis to define a core and an outer periphery; a battery housing configured to house the electrode assembly and electrically connected to one of the first and second electrodes to have a first polarity; a seal configured to seal an open end of the battery housing; and a terminal having a surface exposed to the outside and electrically connected to the other of the first and second electrodes to have a second polarity.

[0158] Preferably, at least one of the first electrode and the second electrode may include an uncoated portion at the long side end where no active material layer is coated.

[0159] Preferably, at least a portion of the uncoated portion can be used as an electrode connector alone, and the uncoated portion may include: 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 inserted between the first portion and the second portion, and at least one of the first portion and the second portion may have a relatively smaller height than the third portion in the winding axis direction.

[0160] In one embodiment, the second portion may have a relatively smaller height than the third portion in the winding axis direction, the battery housing may include an inwardly press-fitted crimped portion at an end adjacent to the open end, and the inner periphery of the crimped portion facing the upper edge of the electrode assembly and the second portion may be spaced apart by a predetermined interval.

[0161] Preferably, the press fit depth (D1) of the rolled edge and the distance (D2) from the inner circumference of the battery casing to the boundary point between the second and third parts can satisfy the relationship D1≤D2.

[0162] In one embodiment, the battery according to this disclosure may further include: a current collector electrically connected to a third portion; and an insulator configured to cover the current collector and having an edge inserted into and fixed between the inner periphery of the rolled edge and the current collector.

[0163] In another embodiment, the outermost diameter of the current collector and the third part can be smaller than the minimum inner diameter of the inner circumference of the rolled edge, and the diameter of the current collector can be greater than or equal to the outermost diameter of the third part.

[0164] In yet another embodiment, the current collector may be located above the rolled edge.

[0165] Preferably, at least a portion of the third part can be bent from the outer periphery toward the core, and the core of the electrode assembly can have a cavity that can be opened outward without being blocked by the bending structure of the third part.

[0166] Therefore, the third part may include multiple segments separated along the winding direction of the electrode assembly, the multiple segments may be bent from the outer periphery toward the core, and the length (R) of the first part in the radial direction and the bending length (H) of the innermost segment of the third part may satisfy the relationship H≤R.

[0167] Preferably, each of the multiple segments can have a rectangular, trapezoidal, triangular, parallelogram, semicircular, or semielliptical structure.

[0168] Preferably, each of the plurality of segments can satisfy at least one of the following conditions: a width condition of 1 mm to 11 mm in the winding direction; a height condition of 2 mm to 10 mm in the winding axis direction; and a separation spacing condition of 0.05 mm to 1 mm in the winding direction.

[0169] Preferably, there may be a gap between the bottom of the cutting groove of the segment and the active material layer, but the gap may be from 0.2 mm to 4 mm.

[0170] Preferably, multiple segments form multiple groups, and segments belonging to the same segment group can be identical to each other in at least one aspect of width in the winding direction, height in the winding axis direction, and separation spacing in the winding direction, and at least one of the multiple groups can be configured with the same winding turn of the electrode assembly.

[0171] Preferably, when the widths of three consecutive adjacent segments in the radial direction of the electrode assembly are W1, W2 and W3 respectively in the winding direction, it may include a combination of segments in which W3 / W2 is smaller than W2 / W1.

[0172] In one embodiment, the seal includes a cap configured to seal the open end of the battery housing and a gasket configured to surround the edge of the cap and press against the top of the battery housing, and a terminal having a second polarity may be the cap.

[0173] In another embodiment, the battery according to this disclosure may further include a current collector electrically connected to an uncoated portion of a second electrode having a first polarity and having an edge at least partially connected to a sidewall of the battery housing. In this case, the sealing body may include a non-polarized cap and a gasket configured to surround the edge of the cap and press against the top of the battery housing, and the battery housing may include riveting terminals mounted to be insulated in a perforation formed at the center of its closed surface and electrically connected to the first electrode to have a second polarity.

[0174] In another aspect of the present invention, a battery pack comprising a plurality of the above-described batteries is also provided.

[0175] Preferably, the battery may have a diameter-to-height ratio greater than 0.4.

[0176] Preferably, the battery may have a shape factor of 46110, 4875, 48110, 4880 or 4680.

[0177] Preferably, the battery may have a resistance of 4 milliohms or lower.

[0178] On one hand, in a battery pack, multiple batteries can be arranged in a predetermined number of columns, and the electrode terminals of each battery and the outer surface of the bottom of the battery casing can be arranged to face upwards.

[0179] On the other hand, the battery pack may include multiple busbars configured to connect multiple batteries in series and in parallel.

[0180] Preferably, the plurality of busbars may be disposed on the upper part of the plurality of batteries, and each busbar may include: a main body portion configured to extend between the electrode terminals of adjacent batteries; a plurality of first busbar terminals configured to extend in one direction of the main body portion and electrically connected to the electrode terminals of the battery located in the one direction; and a plurality of second busbar terminals configured to extend in another direction of the main body portion and electrically connected to the outer surface of the bottom of the battery casing of the battery located in the other direction.

[0181] In another aspect of the invention, a vehicle comprising the above-described battery pack is also provided.

[0182] Beneficial effects

[0183] According to one aspect of this disclosure, by using the uncoated portions protruding from the upper and lower portions of the electrode assembly as electrode connectors, the internal resistance of the battery can be reduced and the energy density can be increased.

[0184] According to another aspect of this disclosure, by improving the structure of the uncoated portion of the electrode assembly to prevent interference between the electrode assembly and the inner circumference of the battery housing during the formation of the rolled edge portion of the battery housing, short circuits inside the cylindrical battery due to partial deformation of the electrode assembly can be prevented.

[0185] According to another aspect of this disclosure, by improving the structure of the uncoated portion of the electrode assembly, it is possible to prevent the uncoated portion from tearing when bent, and the welding strength of the current collector can be improved by sufficiently increasing the number of overlapping layers of the uncoated portion.

[0186] According to another aspect of this disclosure, by applying a segment structure to the uncoated portion of the electrode and optimizing the dimensions (width, height, and spacing) of the segments to sufficiently increase the number of segments stacked in the area used as the welding target area, the physical properties of the area where the current collector is welded can be improved.

[0187] According to another aspect of this disclosure, an electrode assembly with improved energy density and reduced resistance is provided by applying a structure in which the current collector is welded to a bent surface region formed by a bent segment.

[0188] According to another aspect of this disclosure, a cylindrical battery with an improved design is provided, which allows for electrical wiring to be carried out on its upper portion.

[0189] According to another aspect of this disclosure, by improving the structure of the uncoated portion adjacent to the core of the electrode assembly, it is possible to prevent the uncoated portion from blocking the cavity in the core of the electrode assembly when it is bent, thereby facilitating the electrolyte injection process and the welding process between the battery casing (or terminals) and the current collector.

[0190] According to another aspect of this disclosure, since the bent surface area formed by bending the uncoated portion is prepared to correspond to the weld portion having the current collector, the impregnation of the electrolyte can be ensured while the current collector is stably welded.

[0191] According to another aspect of this disclosure, even if the uncoated portion of the electrode assembly is bent, the impregnation of the electrolyte can be adequately guaranteed.

[0192] According to another aspect of this disclosure, a cylindrical battery, a battery pack including the cylindrical battery, and a vehicle may be provided, the cylindrical battery having a structure with low internal resistance, preventing internal short circuits, and improving the welding strength between the current collector and the uncoated portion.

[0193] In particular, this disclosure can provide a cylindrical battery having a diameter-to-height ratio of 0.4 or greater and a resistance of 4 milliohms or less, and can provide battery packs and vehicles including the cylindrical battery.

[0194] In addition, this disclosure may have several other effects, and such effects will be described in each embodiment, or any descriptions that can be readily deduced by those skilled in the art will be omitted for the sake of effect. Attached Figure Description

[0195] 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. Therefore, the present disclosure is not to be construed as being limited to the drawings.

[0196] Figure 1 This is a plan view showing the electrode structure used to manufacture a conventional connectorless cylindrical battery.

[0197] Figure 2 This diagram illustrates the electrode winding process of a conventional connectorless cylindrical battery.

[0198] Figure 3 This diagram illustrates the process of welding a current collector to the bent surface area of ​​an uncoated portion in a conventional seamless cylindrical battery.

[0199] Figure 4 This is a plan view showing the structure of the electrode according to the first embodiment of the present disclosure.

[0200] Figure 5 This is a plan view showing the electrode structure according to the second embodiment of the present disclosure.

[0201] Figure 6 This is a plan view showing the electrode structure according to the third embodiment of the present disclosure.

[0202] Figure 7aThis is a plan view showing the electrode structure according to the fourth embodiment of the present disclosure.

[0203] Figure 7b This is a diagram illustrating the definitions of the width, height, and separation spacing of a segment according to one embodiment of the present disclosure.

[0204] Figure 7c This is a diagram showing the arc formed by the lower end of the width of the segment relative to the core center of the electrode assembly when the electrode is wound according to an embodiment of the present disclosure.

[0205] Figure 7d This schematically illustrates the segment heights h1, h2, h3, h4, and core radius r according to an embodiment of the present disclosure. c A diagram showing the relationship between the radii r1, r2, r3, and r4 of the winding turns where segments begin to appear.

[0206] Figure 7e It is used to determine the maximum value (h) of the segment height (H) in the variable segment height region. max Concept map.

[0207] Figure 7f This is a diagram used to explain the formula for determining the lower interior angle (θ) of a segment.

[0208] Figure 7g This is a plan view showing a modified structure of the electrode according to the fourth embodiment of the present disclosure.

[0209] Figure 7h and Figure 7i This is a top plan view showing an embodiment in which multiple segment alignment portions (bending surface areas) and multiple electrolyte impregnation portions are radially formed at one end of the electrode assembly when the electrode according to a variant of the present disclosure is wound into an electrode assembly.

[0210] Figure 7j This is a diagram illustrating the structure of a segment group included in a fan-shaped segment alignment portion according to an embodiment of the present disclosure, arranged in different winding turns.

[0211] Figure 8a This is a plan view showing the electrode structure according to the fifth embodiment of the present disclosure.

[0212] Figure 8b This is a diagram illustrating the definitions of the width, height, and separation spacing of a segment according to another embodiment of the present disclosure.

[0213] Figure 8c This is a plan view showing a modified structure of the electrode according to the fifth embodiment of the present disclosure.

[0214] Figure 9This is a diagram illustrating the segmental structure of various variations according to this disclosure.

[0215] Figure 10a This is a schematic diagram showing a cross-section of the bent surface region formed by bending a segment toward the core of the electrode assembly.

[0216] Figure 10b This is a schematic top perspective view of the electrode assembly in which the bent surface area is formed.

[0217] Figure 10c It is a graph showing the result of counting the number of segments stacked in the radial direction in the bent surface area of ​​the positive electrode formed at the upper part of the electrode assembly according to embodiments 1-1 to 1-7 and the comparative example.

[0218] Figure 10d It is a graph showing the result of counting the number of segments stacked in the radial direction in the bent surface area of ​​the positive electrode formed at the upper part of the electrode assembly according to embodiments 2-1 to 2-5, embodiments 3-1 to 3-4, embodiments 4-1 to 4-3, and embodiments 5-1 and 5-2.

[0219] Figure 10e It is a graph showing the result of counting the number of segments stacked in the radial direction in the bent surface area of ​​the positive electrode formed at the upper part of the electrode assembly according to embodiments 6-1 to 6-6 and embodiments 7-1 to 7-6.

[0220] Figure 10f This is a top plan view of an electrode assembly according to an embodiment of the present disclosure, showing a uniform stacking area b1 and a reduced stacking area b2 in the bent surface region of the segment.

[0221] Figure 11 This is a cross-sectional view of a wound-core type electrode assembly cut along the Y-axis direction (winding axis direction), in which the first electrode (positive electrode) and the second electrode (negative electrode) are electrodes of the first embodiment.

[0222] Figure 12 This is a cross-sectional view of a wound core type electrode assembly cut along the Y-axis direction (winding axis direction), in which the first electrode (positive electrode) and the second electrode (negative electrode) employ electrodes of the second embodiment.

[0223] Figure 13 This is a cross-sectional view of a wound-core type electrode assembly cut along the Y-axis direction (winding axis direction), in which the first electrode (positive electrode) and the second electrode (negative electrode) employ any of the electrodes of the third to fifth embodiments (variations thereof).

[0224] Figure 14It is a cross-sectional view of the electrode assembly according to another embodiment of the present disclosure, cut along the Y-axis direction (winding axis direction).

[0225] Figure 15 It is a cross-sectional view of the electrode assembly according to another embodiment of the present disclosure, cut along the Y-axis direction (winding axis direction).

[0226] Figure 16 It is a cross-sectional view of the electrode assembly according to another embodiment of the present disclosure, cut along the Y-axis direction (winding axis direction).

[0227] Figure 17 This is a cross-sectional view showing a cylindrical battery according to an embodiment of the present disclosure, cut along the Y-axis.

[0228] Figure 18 This is a cross-sectional view showing a cylindrical battery according to another embodiment of the present disclosure, cut along the Y-axis.

[0229] Figure 19 This is a cross-sectional view of a cylindrical battery according to another embodiment of the present disclosure, cut along the Y-axis.

[0230] Figure 20 This is a cross-sectional view showing a cylindrical battery according to another embodiment of the present disclosure, cut along the Y-axis.

[0231] Figure 21 This is a cross-sectional view showing a cylindrical battery according to another embodiment of the present disclosure, cut along the Y-axis.

[0232] Figure 22 This is a cross-sectional view showing a cylindrical battery according to another embodiment of the present disclosure, cut along the Y-axis.

[0233] Figure 23 This is a cross-sectional view showing a cylindrical battery according to another embodiment of the present disclosure, cut along the Y-axis.

[0234] Figure 24 This is a cross-sectional view showing a cylindrical battery according to another embodiment of the present disclosure, cut along the Y-axis.

[0235] Figure 25 This is a cross-sectional view showing a cylindrical battery according to another embodiment of the present disclosure, cut along the Y-axis.

[0236] Figure 26 This is a top plan view showing the structure of a first current collector according to one embodiment of the present disclosure.

[0237] Figure 27 This is a top plan view showing the structure of a second current collector according to one embodiment of the present disclosure.

[0238] Figure 28 It is a top plan view showing the electrical connection of multiple cylindrical batteries.

[0239] Figure 29 yes Figure 28 A magnified view of a portion of the image.

[0240] Figure 30 This is a schematic diagram illustrating a battery pack according to one embodiment of the present disclosure.

[0241] Figure 31 This is a schematic diagram of a vehicle including a battery pack according to one embodiment of the present disclosure. Detailed Implementation

[0242] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Before the description, it should be understood that the terminology used in the specification and appended claims should not be construed as limited to its general and dictionary meaning, but should be interpreted based on the meaning and concepts corresponding to the technical aspects of the present disclosure, in accordance with the principle that inventors are allowed to appropriately define terms to obtain the best interpretation.

[0243] Therefore, the descriptions presented herein are merely preferred embodiments and are for illustrative purposes only, and are not intended to limit the scope of this disclosure. It should be understood that other equivalents and modifications may be made to the descriptions without departing from the scope of this disclosure.

[0244] Furthermore, to aid in understanding this disclosure, the drawings are not drawn to scale and some component dimensions may be enlarged. Additionally, in different embodiments, the same elements may be given the same reference numerals.

[0245] When explaining that two objects are identical, this means that these objects are "substantially identical." Therefore, substantially identical objects can include those considered to have low deviations in the field, such as deviations within 5%. Furthermore, when explaining that certain parameters are uniform across a region, this can mean that the parameters are uniform in terms of average value across the corresponding region.

[0246] Although the terms first, second, etc., are used to describe different elements, these elements are not limited by the terms. These terms are used to distinguish one element from another, and unless otherwise stated, the first element can be the second element.

[0247] Throughout this specification, unless otherwise stated, each element may be singular or plural.

[0248] When an element is "above (or below)" or "on (or under) another element," the element may be on the upper (or lower) surface of the other element, and there may be an intermediate element between the one element and the other element above (or below) the one element.

[0249] Furthermore, when an element is referred to as “connected,” “linked,” or “attached” to another element, the element may be directly connected or linked to the other element. However, it should be understood that there may be intermediate elements between each element, or each element may be “connected,” “linked,” or “attached” to each other via another element.

[0250] Furthermore, unless the context clearly indicates otherwise, singular expressions used in this specification include plural expressions. In this application, terms such as “comprising” or “including” should not be construed as necessarily including all the various components or steps described in the specification, and should be construed as potentially excluding some components or steps, or potentially including additional components or steps.

[0251] Throughout this specification, unless otherwise expressly stated, “A and / or B” means A or B or both A and B, and unless otherwise expressly stated, “C to D” means C or greater and D or less.

[0252] For ease of description, the direction along the length of the winding axis of the coiled electrode assembly is referred to herein as the axial direction Y. Furthermore, the direction around the winding axis is referred to herein as the circumferential direction or outer circumferential direction X. Additionally, directions approaching or away from the winding axis are referred to as radial directions. Specifically, the direction approaching the winding axis is called the centripetal direction, and the direction away from the winding axis is called the centrifugal direction.

[0253] First, an electrode assembly according to one embodiment of the present disclosure will be described. The electrode assembly may be a wound-core type electrode assembly, wherein a first electrode and a second electrode having a sheet shape and a diaphragm inserted between the first electrode and the second electrode are wound in one direction. However, the present disclosure is not limited to the type of electrode assembly.

[0254] Preferably, at least one of the first electrode and the second electrode includes an uncoated portion, wherein the long side of the uncoated portion is not coated with active material in the winding direction. At least a portion of the uncoated portion itself serves as an electrode connector. The uncoated portion includes: a core-side uncoated portion adjacent to the core of the electrode assembly; an outer peripheral-side uncoated portion adjacent to the outer peripheral surface of the electrode assembly; and an intermediate uncoated portion inserted between the core-side uncoated portion and the outer peripheral-side uncoated portion.

[0255] Preferably, at least one of the uncoated core side and the uncoated outer peripheral side has a relatively lower height than the uncoated middle side.

[0256] Figure 4 This is a plan view showing the structure of the electrode 40 according to the first embodiment of the present disclosure.

[0257] refer to Figure 4 The 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 conductive metal (e.g., aluminum or copper) and is appropriately selected according to the polarity of the electrode 40. The active material layer 42 is formed on at least one surface of the current collector 41. The active material layer 42 is formed along a winding direction X. The electrode 40 includes an uncoated portion 43 at the long side end in the winding direction X. The uncoated portion 43 is a local area of ​​the current collector 41 where the active material layer 42 is formed. The region of the current collector 41 where the active material layer 42 is formed may be referred to as the active material portion.

[0258] In electrode 40, the width of the active material portion along the short side of the current collector 41 can be from 50 mm to 120 mm, and the length of the active material portion along the long side of the current collector 41 can be from 3 m to 5 m. Therefore, the ratio of the short side to the long side of the active material portion can be from 1.0% to 4.0%.

[0259] Preferably, in the electrode 40, the width of the active material portion along the short side of the current collector 41 can be 60 mm to 70 mm, and the length of the active material portion along the long side of the current collector 41 can be 3 m to 5 m. Therefore, the ratio of the short side to the long side of the active material portion can be 1.2% to 2.3%.

[0260] The ratio of the short side to the long side of the active material portion is significantly less than 6% to 11%, which is the ratio of the short side to the long side of the active material portion of the electrode used in cylindrical batteries with a form factor of 1865 or 2170.

[0261] Preferably, the current collector 41 may have an elongation of 1.5% to 3.0% and 25 kgf / mm². 2 Up to 35 kgf / mm 2 The tensile strength. Elongation and tensile strength can be measured according to the measurement method of IPC-TM-650. The electrode 40 is manufactured by forming an active material layer 42 on the current collector 41 and then compressing it. When compressed, the uncoated area 43 and the area of ​​the active material layer 42 have different elongations. Therefore, after compression, expansion occurs on the electrode 40, and the longer the electrode 40, the more severe the expansion.

[0262] When the length of electrode 40 is approximately 4 m, optimization of the elongation and tensile strength of current collector 41 reduces the warpage length after compression to less than 20 mm. When the expanded electrode 40 is unwound, the warpage length is the maximum deflection of electrode 40 in the winding direction X. The maximum deflection can be measured at the outer periphery. Because electrode 40, in which the elongation and tensile strength of current collector 41 are optimized, has a small warpage length, there are no wavy defects during grooving operations on the uncoated portion 43 or during winding of electrode 40.

[0263] The current collector 41 is more prone to breakage due to its lower elongation. When the elongation of the current collector 41 is less than 1.5%, the rolling efficiency of the current collector 41 decreases, therefore, when the electrode 40 coated with the active material layer 42 is pressed onto the current collector 41, breakage may occur within the current collector 41. Simultaneously, when the elongation of the current collector 41 exceeds 3.0%, the elongation of the active material portion of the electrode 40 increases, thus significantly increasing the warpage length. If the tensile strength of the current collector 41 is less than 25 kgf / mm... 2 or greater than 35 kgf / mm 2 When this happens, the electrode processing efficiency of electrode 40 deteriorates.

[0264] For positive current collectors made of aluminum foil, warping is particularly problematic. According to this disclosure, warping is addressed by using an elongation of 1.5% to 3.0% and a tensile strength of 25 kgf / mm². 2 Up to 35 kgf / mm 2 Using aluminum foil as a current collector can suppress warping. Ideally, an active material layer should be formed on the current collector and used as the positive electrode.

[0265] Preferably, an insulating coating layer 44 may be formed at the boundary between the active material layer 42 and the uncoated portion 43. Hereinafter, the insulating coating layer 44 may be simply referred to as the insulating layer 44. The insulating coating layer 44 is formed such that at least a portion of it overlaps with the boundary between the active material layer 42 and the uncoated portion 43. The insulating coating layer 44 prevents short circuits between two electrodes facing each other with different polarities and a diaphragm inserted therebetween. The insulating coating layer 44 has a width of 0.3 mm to 5 mm and can cover the boundary between the active material layer 42 and the uncoated portion 43. The width of the insulating coating layer 44 can be varied along the winding direction of the electrode 40. The insulating coating layer 44 may include a polymer resin and an inorganic filler such as Al2O3. Since the portion of the current collector 41 covered by the insulating coating layer 44 is not an area coated with the active material layer, it can be considered an uncoated portion.

[0266] The uncoated portion 43 includes: a core-side uncoated portion B1 adjacent to the core side of the electrode assembly; an outer peripheral-side uncoated portion B3 adjacent to the outer periphery of the electrode assembly; and an intermediate uncoated portion B2 inserted between the core-side uncoated portion B1 and the outer peripheral-side uncoated portion B3.

[0267] The uncoated portion B1 on the core side, the uncoated portion B3 on the outer periphery side, and the uncoated portion B2 in the middle can be defined as the uncoated portion of the region adjacent to the core, the uncoated portion of the region adjacent to the outer periphery, and the uncoated portion of the remaining region other than the aforementioned regions when the electrode 40 is wound into a core-type electrode assembly, respectively.

[0268] In the following text, the uncoated portion B1 on the core side, the uncoated portion B3 on the outer periphery side, and the uncoated portion B2 in the middle will be referred to as the first part, the second part, and the third part, respectively.

[0269] In one embodiment, the first portion B1 may be an uncoated portion of the electrode region including the innermost wound turn, and the second portion may be an uncoated portion of the electrode region including the outermost wound turn. The number of wound turns may be based on the core-side end of the electrode assembly.

[0270] In another embodiment, the boundary of B1 / B2 may be suitably defined as the point where the height (or variation pattern) of the uncoated portion changes significantly from the core of the electrode assembly toward the periphery, or as a point based on a predetermined percentage (%) of the radius of the electrode assembly (e.g., 5%, 10%, 15%, etc. of the radius).

[0271] The boundary of B2 / B3 can be defined as the point where the height (or variation pattern) of the uncoated portion changes significantly from the outer periphery of the electrode assembly toward the core, or as a predetermined percentage (%) point based on the radius of the electrode assembly (e.g., 85%, 90%, 95%, etc. of the radius). When the boundaries of B1 / B2 and B2 / B3 are specified, the third part B2 can be automatically specified.

[0272] If only the boundaries of B1 / B2 are specified, the boundaries of B2 / B3 can be appropriately selected at a point near the outer periphery of the electrode assembly. In one embodiment, the second portion can be defined as the uncoated portion of the electrode region constituting the outermost winding turn. Conversely, when only the boundaries of B2 / B3 are specified, the boundaries of B1 / B2 can be appropriately selected at a point near the core of the electrode assembly. In one embodiment, the first portion can be defined as the uncoated portion of the electrode region constituting the innermost winding turn.

[0273] It is possible that another structure is inserted between the first part B1 and the third part B2. Furthermore, it is possible that another structure is inserted between the third part B2 and the second part B3.

[0274] In the first embodiment, the height of the uncoated portion 43 is not constant and varies relatively in the winding direction X. That is, the height (length in the Y-axis direction) of the second portion B3 is 0 or greater, but relatively smaller than the heights of the first portion B1 and the third portion B2. Here, the height of each portion can be an average height or a maximum height, which also applies below. In the winding direction, the third portion B2 is longer than the first portion B1 and the second portion B3.

[0275] Figure 5 This is a plan view showing the structure of the electrode 45 according to the second embodiment of the present disclosure.

[0276] refer to Figure 5 Except that the height of the second part B3 gradually decreases towards the outer periphery, the electrode 45 of the second embodiment is substantially the same as the electrode 45 of the first embodiment.

[0277] In one variant, the second part B3 can be transformed into a stepped shape in which the height gradually decreases (see dashed line).

[0278] Figure 6 This is a plan view showing the structure of the electrode 50 according to the third embodiment of this disclosure.

[0279] refer to Figure 6 In the electrode 50 of the third embodiment, the height of the first portion B1 and the second portion B3 is 0 or greater, but relatively smaller than the height of the third portion B2. Furthermore, the heights of the first portion B1 and the second portion B3 may be the same or different.

[0280] Preferably, the height of the third part B2 can have a stepped shape that gradually increases from the core to the outer periphery.

[0281] Pattern 1 to Figure 7j The third part B2 is classified based on the position of the height variation of the uncoated portion 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 can be adjusted to distribute stress as much as possible during the bending process of the uncoated portion 43. The stress distribution is to prevent the uncoated portion 43 from tearing when bending towards the core of the electrode assembly.

[0282] The width (d) of the first part B1 is designed by applying the condition that the core does not cover the electrode assembly when the pattern of the third part B2 is bent toward the core. B1 The core refers to the cavity located at the center of the winding of the electrode assembly.

[0283] In one embodiment, the width (d) of the first portion B1 B1 The bending length can be increased proportionally to the bending length of pattern 1. The bending length corresponds to the height of the bending point of the pattern.

[0284] Preferably, the width (d) of the first part B1 B1 The width of the winding turn formed by the first portion B1 can be set such that the radial width is equal to or greater than the bending length of pattern 1. In a variant, the width (d) of the first portion B1 is... B1 The value obtained by subtracting the radial width of the winding turn formed by the first part B1 from the bending length of pattern 1 is less than 0 or equal to or less than 10% of the radius of the core.

[0285] In one specific embodiment, when electrode 60 is used to manufacture an electrode assembly for a cylindrical battery with a form factor of 4680, the width (d) of the first portion B1 is determined based on the diameter of the electrode assembly's core and the bending length of pattern 1. B1 The setting can be set from 180mm to 350mm.

[0286] In one implementation, the width of each pattern can be designed as one or more winding turns constituting an electrode assembly.

[0287] In a variant, the height of the third part B2 can have a stepped shape, where the height increases from the core toward the periphery and then decreases.

[0288] In another variation, the second part B3 can be modified to have the same structure as the second embodiment.

[0289] In yet another variation, the pattern structure applied to the third part B2 can be extended to the second part B3 (see dashed line).

[0290] The third part B2 can be folded in the radial direction of the electrode assembly based on an imaginary line connecting the front ends of the first part B1 and the second part B3 in the winding direction.

[0291] Figure 7a This is a plan view showing the structure of the electrode 60 according to the fourth embodiment of the present disclosure.

[0292] refer to Figure 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 greater, but 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.

[0293] Preferably, at least a partial region of the third part B2 may include a plurality of segments 61. The height of the plurality of segments 61 may gradually increase from the core toward the outer periphery. The plurality of segments 61 have a geometry in which the width decreases from the bottom to the top. Preferably, the geometry is trapezoidal. The corners or vertices of the trapezoid are rounded or beveled, rather than sharp. As will be described later, the shape of the geometry may be varied in various ways.

[0294] Segment 61 can be formed by laser grooving. Segment 61 can also be formed by known metal foil cutting processes such as ultrasonic cutting or stamping.

[0295] The third part B2 can be folded in the radial direction of the electrode assembly based on an imaginary line connecting the front ends of the first part B1 and the second part B3 in the winding direction. In this case, segment 61 can be bent based on the bottom of the cut groove. The height of the bottom of the cut groove between segments can correspond to the height of the first part B1 and / or the second part B3.

[0296] In the fourth embodiment, to prevent damage to the active material layer 42 and / or the insulating coating layer 44 during bending of the uncoated portion 43, it is preferable to have a groove at the bottom between the segments 61. Figure 7b A predetermined gap is provided between the portion indicated by G and the active material layer 42. This is because when the uncoated portion 43 is bent, stress is concentrated near the bottom of the cutting groove 63.

[0297] The gap can be varied along the winding direction of electrode 60. The gap is 0.2 mm to 4 mm, preferably 1.5 mm to 2.5 mm.

[0298] When electrode 60 is the negative electrode, the gap is more preferably 1.0 mm or greater, and when electrode 60 is the positive electrode, the gap is more preferably 2.0 mm or greater.

[0299] If the gap is adjusted within the appropriate numerical range, the active material layer 42 and / or the insulating coating layer 44 can be prevented from being damaged near the bottom of the cutting groove 63 due to the stress generated during bending of the uncoated portion 43.

[0300] Preferably, when the electrode 40 is wound into an electrode assembly, at least a portion of the insulating coating layer 44 may be exposed to the outside of the diaphragm. In this case, the insulating coating layer 44 may support the bending point when the segment 61 is bent.

[0301] The gap prevents the active material layer 42 and / or the insulating coating layer 44 from being damaged due to tolerances during grooving or cutting of the segment 61. The gap may be substantially the same or may vary in one direction parallel to the winding direction. In the latter case, the gap of multiple segments may be varied individually, in groups, or in two or more groups along one direction parallel to the winding direction.

[0302] The lower end of the segment 61 formed by the cutting groove 63 can be the area that causes bending during the bending process of the segment 61. That is, during the bending process, the bending resistance is almost constant from the lower end of the uncoated portion 43 to near the bottom of the cutting groove 63, then decreases rapidly near the bottom of the cutting groove 63, and then remains almost constant until it reaches the top of the segment 61.

[0303] The lower end of the cutting groove 63 and the insulating coating layer 44 can be spaced 0.2mm to 2.0mm apart. If the separation distance is less than 0.2mm, the above-mentioned damage prevention effect cannot be fully demonstrated; if the separation distance is greater than 2.0mm, the bending support effect of the insulating coating layer 44 will be reduced without increasing the damage prevention effect.

[0304] In a direction parallel to the winding direction, the separation distance between the lower end of the cutting groove 63 and the insulating coating layer 44 can be substantially the same or can be varied. In the latter case, the separation distance of multiple segments can be varied individually, in groups, or in two or more groups along a direction parallel to the winding direction.

[0305] When the electrode 60 is wound, the end of the insulating coating layer 44 in the winding axis Y direction can be located in the range of -2 mm to 2 mm along the winding axis direction based on the end of the diaphragm. The insulating coating layer 44 can prevent short circuits between two electrodes facing each other and having different polarities when a diaphragm is inserted between them, and can support the bending point when the segment 61 is bent. To improve the effect of preventing short circuits between the two electrodes, the insulating coating layer 44 can be exposed outside the diaphragm. Furthermore, to further maximize the effect of preventing short circuits between the two electrodes, the width of the insulating coating layer 44 can be increased so that the end of the insulating coating layer 44 in the winding axis Y direction is located above the lower end of the cutting groove 63. In one embodiment, the end of the insulating coating layer 44 in the winding axis direction can be located in the range of -2 mm to +2 mm based on the lower end of the cutting groove 63. The thickness of the insulating coating layer 44 can be smaller than the thickness of the active material layer. Therefore, when the electrode 60 is stacked with the membrane, the insulating coating layer 44 may have a weaker contact with the membrane or form a gap with the membrane compared to the degree of adhesion between the active material layer 42 of the electrode 60 and the membrane.

[0306] The insulating coating 44 provides support so that the base of the uncoated portion does not deform during the bending process of segment 61. However, even if the support does not overcome the bending force and causes slight deformation, the deformation of the insulating coating 44 may not immediately and directly affect the diaphragm due to the small gap between the insulating coating 44 and the diaphragm membrane.

[0307] Multiple segments 61 can form multiple segment groups from the core toward the outer periphery. In the segment group, adjacent segments in the winding direction can be identical in at least one of the following aspects: the lower inner angle of the segment, the axial height of the segment, the width of the segment in the winding direction, the shape of the segment, the height of the bottom of the cutting groove between the two segments, and the separation distance between the two segments.

[0308] Figures 7a to 7j An exemplary embodiment is shown in which segments belonging to the same segment group have substantially the same width, height, and separation spacing.

[0309] In segments belonging to different segment groups, at least one identical factor within the same group can be different.

[0310] On the other hand, the separation distance between multiple segments can gradually or progressively increase from the core toward the periphery in one group or in two or more groups, and vice versa.

[0311] On the other hand, the separation distance between multiple segments can be gradually or progressively increased from the core toward the periphery in one group or in two or more groups, and then gradually or progressively decreased, and vice versa.

[0312] On the other hand, in multiple segments, the gap between the lower end of the cutting groove 63 and the insulating coating layer 44 or the active material layer 42 can gradually or progressively increase from the core toward the outer periphery, and vice versa.

[0313] On the other hand, in multiple segments, the gap between the lower end of the cutting groove 63 and the insulating coating layer 44 or the active material layer 42 can gradually increase or decrease from the core toward the outer periphery, and vice versa.

[0314] exist Figure 7a In this embodiment, the heights of the segments in different segment groups are different. In the electrode assembly, the diaphragm SP may face the active material layer 42 and / or the insulating coating layer 44 of the electrode 60. Preferably, the position of the ends of the diaphragm SP can be adjusted to improve the impregnation of the electrolyte.

[0315] In the electrode assembly, when a reference line DL is defined as the line extending parallel to the winding direction X based on the point with the minimum height in the first part B1, the second part B3, and the third part B2, and the segment with the minimum height among the multiple segments is called the minimum segment, the end SL of the diaphragm SP in the width direction can be located within 30% of the height Ha of the minimum segment based on the reference line DL in the outward direction of the electrode assembly. Here, the outward direction of the electrode assembly refers to the direction from the active material layer 42 of the electrode 60 toward the orientation of the uncoated portion 43.

[0316] Alternatively, the end SL of the diaphragm SP in the width direction may be located within 30% of the height Ha of the minimum segment based on the reference line DL in the inward direction of the electrode assembly. Here, the inward direction of the electrode assembly refers to the direction from the uncoated portion 43 of the electrode 60 toward the orientation of the active material layer 42.

[0317] Preferably, the height Ha of the minimum segment can substantially correspond to the minimum height value of the segment bent in the radial direction of the electrode assembly.

[0318] The baseline DL, which extends parallel to the winding direction X from the point with the minimum height in the first part B1, the second part B3, and the third part B2, corresponds to the bottom of the cutting groove 63 between adjacent segments, and the bottom of the cutting groove can be referred to as the notching groove.

[0319] According to one embodiment of this disclosure, by controlling the end of the separator SP to be positioned close to the reference line DL in the width direction, the electrolyte flows into the electrode assembly along the slotted openings (empty spaces), thereby increasing the impregnation rate. Specifically, when the electrolyte is injected into the battery casing into which the electrode assembly is inserted, the electrolyte moves to the slotted openings between the uncoated segments of the electrode. The electrolyte also impregnates into the slotted openings between the segments (i.e., the end of the separator close to the reference line) and ultimately impregnates into the active material layer of the electrode. As a result, the uniformity of electrolyte impregnation within the electrode assembly is increased.

[0320] As the end SL of the diaphragm SP extends outward in the electrode assembly, the welding characteristics are adversely affected, and as the end SL of the diaphragm SP is positioned towards the inside of the electrode assembly, the risk of short circuit between the positive and negative electrodes increases, which may be a problem.

[0321] Therefore, in this disclosure, the end SL of the diaphragm SP in the width direction is controlled to be within 30% of the height of the minimum segment based on the reference line DL in the outward direction of the electrode assembly, or the end SL of the diaphragm SP in the width direction is controlled to be within 30% of the height of the minimum segment based on the reference line DL in the inward direction of the electrode assembly.

[0322] According to one embodiment of the present disclosure, the end SL of the diaphragm SP in the width direction may be located within 1.5 mm in the outward direction of the electrode assembly based on the reference line DL, or the end SL of the diaphragm SP in the width direction may be located within 1.5 mm in the inward direction of the electrode assembly based on the reference line DL.

[0323] Figure 7b This is a diagram defining the width D, height H, and separation spacing P of segment 61 according to one embodiment of this disclosure.

[0324] refer to Figure 7b The width (D), height (H), and separation spacing (P) of segment 61 are designed to prevent the uncoated portion 43 from being torn near the bending point during bending and to prevent abnormal deformation of the uncoated portion 43, while also sufficiently increasing the number of overlapping layers of the uncoated portion 43 to ensure sufficient weld strength.

[0325] Segment 61 is bent at line G, which passes through the bottom of the cut groove 63, or at the top of that line. The cut groove 63 allows segment 61 to be bent smoothly and easily in the radial direction of the electrode assembly.

[0326] The width (D) of segment 61 is defined as the length between two points where two straight lines extending from the sides 63b of segment 61 intersect with a straight line extending from the bottom 63a of the cutting groove 63. The height (H) of segment 61 is defined as the shortest distance between the uppermost edge of segment 61 and a straight line extending from the bottom 63a of the cutting groove 63. The separation distance (P) of segment 61 is defined as the length between two points where a straight line extending from the bottom 63a of the cutting groove 63 intersects with a straight line extending from the sides 63b connected to the bottom 63a. When the sides 63b and / or the bottom 63a are curved, the straight lines can be replaced by tangents extending from the sides 63b and / or the bottom 63a at the intersection of the sides 63b and the bottom 63a.

[0327] Preferably, the width (D) of segment 61 is 1 mm or greater. If D is less than 1 mm, when segment 61 is bent toward the core, there may be areas or gaps where segment 61 does not overlap sufficiently to ensure adequate weld strength.

[0328] Preferably, the width (D) of segment 61 can be adaptively adjusted according to the radius of the winding turn in which segment 61 is located, so that when segment 61 bends toward the core of the electrode assembly, segment 61 overlaps well in the radial direction.

[0329] Figure 7c This illustrates the lower end of the width (D) of segment 61 defined by segment 61 when the electrode 60 is wound according to one embodiment of the present disclosure. Figure 7b Line D in ab A diagram of the arc (A1A2) formed relative to the core center O of the electrode assembly.

[0330] refer to Figure 7c Arc (A1A2) has a length corresponding to the width (D) of segment 61, and has a circumferential angle (Φ) with the core center of the electrode assembly. The circumferential angle (Φ) can be defined as the angle between two line segments connecting the two ends of arc (A1A2) and the core center O on a plane perpendicular to the winding axis passing through arc (A1A2).

[0331] When the lengths of the arcs (A1A2) of segment 61 are the same, the circumferential angle (Φ) decreases as the radius (r) of the winding turn containing segment 61 increases. Conversely, when the circumferential angle (Φ) of segment 61 is the same, the length of the arc (A1A2) increases proportionally as the radius (r) of the winding turn containing segment 61 increases.

[0332] The circumferential angle (Φ) affects the bending quality of segment 61. In the figure, the solid arrow indicates the direction of the force applied to the bending segment 61, and the dashed arrow indicates the bending direction of segment 61. The bending direction is towards the core center O.

[0333] The circumferential angle (Φ) of segment 61 can be 45 degrees or less, preferably 30 degrees or less, depending on the radius (r) of the winding turn in which segment 61 is located, in order to improve bending uniformity and prevent cracking.

[0334] In one respect, the circumferential angle (Φ) of segment 61 may gradually increase or decrease along the radial direction of the electrode assembly within the above-mentioned numerical range. In another respect, the circumferential angle (Φ) of segment 61 may gradually increase or decrease along the radial direction of the electrode assembly within the above-mentioned numerical range, and vice versa. In yet another respect, the circumferential angle (Φ) of segment 61 may be substantially the same along the radial direction of the electrode assembly within the above-mentioned numerical range.

[0335] According to experiments, when the circumferential angle (Φ) of segment 61 exceeds 45 degrees, the bending shape of segment 61 becomes uneven. The difference between the force applied to the middle of segment 61 and the force applied to the sides increases, thus segment 61 is compressed unevenly in the circumferential direction. Furthermore, if the pressing force is increased to achieve uniform bending, cracks may appear in the uncoated portion 43 near the cutting groove 63.

[0336] In one embodiment, the circumferential angles (Φ) of the segments 61 included in the electrode 60 are substantially the same, and the width of the segments 61 may increase proportionally with the radius (r) of the winding turn in which the segments 61 are located. The term "substantially the same" means that they are completely identical or have a difference of less than 5%.

[0337] For example, when the radius of the electrode assembly is 22 mm and the radius of the core is 4 mm, and segment 61 is set starting from the winding turn located at a point with a radius of 7 mm, if the circumferential angle (Φ) of segment 61 is consistently 28.6 degrees, then the width (D) of segment 61 can be increased proportionally according to the radius (r) of the winding turn in which segment 61 is located, as shown in Table 1 below. That is, whenever the radius (r) of the winding turn increases by 1 mm, the width of segment 61 can be increased by approximately 0.5 mm at the same rate.

[0338] [Table 1]

[0339] Winding turn radius (mm) 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0 21.0 22.0 Segment width (D, mm) 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 Circumferential angle (degrees) 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6

[0340] Preferably, the width D(r) of the segment 61 located in the winding turn with radius r based on the core center O of the electrode assembly can be determined within the range of the following formula 1.

[0341] <Formula 1>

[0342] 1≤D(r)≤(2*π*r / 360°)*45°

[0343] Preferably, as the radius r of the winding turn containing segment 61 based on the core center of the electrode assembly increases, the width D(r) of multiple segments 61 in the winding direction gradually or progressively increases, and vice versa.

[0344] On the other hand, as the radius r of the core center of the winding turn where segment 61 is located increases, the width D(r) of multiple segments 61 in the winding direction gradually or progressively increases in the range of 1 mm to 11 mm, and vice versa.

[0345] On the other hand, as the radius r of the core center of the electrode assembly increases, the width D(r) of the multiple segments 61 in the winding direction gradually or progressively increases and then gradually or progressively decreases, and vice versa.

[0346] On the other hand, as the radius r of the core center of the winding turn where segment 61 is located increases, the width D(r) of multiple segments 61 in the winding direction gradually or progressively increases in the range of 1 mm to 11 mm, and then gradually or progressively decreases, and vice versa.

[0347] On the other hand, as the radius r of the winding turn containing segment 61 increases, the rate of change of the width D(r) of segment 61 can be the same or different.

[0348] On the other hand, as the radius r of the winding turn where segment 61 is located increases, the rate of change of the width D(r) of segment 61 can be the same or different in the range of 1 mm to 11 mm.

[0349] Refer again Figure 7b The height (H) of segment 61 can be 2 mm or greater. If D2 is less than 2 mm, then when segment 61 bends toward the core, there may be empty spaces (gap) or areas where the overlap of segments 61 is insufficient to guarantee weld strength.

[0350] The height (H) of segment 61 can be determined by applying the condition that segment 61 does not obstruct the core when bending toward the core. Preferably, the height (H) of segment 61 can be adjusted so that the core can be open to the outside at 90% or more of its diameter.

[0351] Preferably, the height (H) of segment 61 can increase from the core toward the outer periphery, depending on the radius of the core and the radius of the winding turn in which segment 61 is located.

[0352] In one implementation, the height (H) of segment 61 increases from h1 to h as the radius of the winding turn increases. N Assuming the height of segment 61 is h when the step size is gradually increased by N steps, k (k is a natural number from 1 to N), including those with height h k The initial radius of the winding turn of segment 61 is r k And the radius of the core is r c At that time, the height h1 to h of segment 61 can be determined. N It satisfies the following formula 2.

[0353] <Formula 2>

[0354] 2mm≤h k ≤r k -α*r c (Preferably, α is 0.90 to 1)

[0355] If the height of segment 61 (h) k If Formula 2 is satisfied, then even if segment 61 bends toward the core, it can still open 90% or more of the core's diameter to the outside.

[0356] In one embodiment, the total radius of the winding of electrode 60 is 22 mm, and the height of segment 61 starts from 3 mm. Whenever the radius of the winding including segment 61 increases by 1 mm, the height of segment 61 increases sequentially to 3 mm, 4 mm, 5 mm, and 6 mm, and the height can remain substantially the same (6 mm) in the remaining winding turns. That is, within the radius of the entire winding turn, the radial width of the variable height region of segment 61 is 3 mm, and the remaining radial region corresponds to the uniform height region.

[0357] In this case, based on the radius (r) of the electrode assembly core cWhen α is 1 and the equality condition is applied to the inequality on the right, the starting radii r1, r2, r3, r4 of the winding turns including segments 61 with heights of 3mm, 4mm, 5mm and 6mm can be shown in Table 2 below.

[0358] [Table 2]

[0359]

[0360] When segment 61 is positioned at the radius shown in Table 2, the core will not be blocked by segment 61 even if segment 61 bends towards the core. Simultaneously, r1, r2, r3, and r4 shown in Table 2 can be offset towards the core according to the value of α. In one embodiment, when α is 0.90, r1, r2, r3, and r4 can be offset towards the core by 10% of the core radius. In this case, when segment 61 bends towards the core, 10% of the core radius is blocked by segment 61. r1, r2, r3, and r4 shown in Table 2 are the limit values ​​for the starting position of segment 61. Therefore, the position of segment 61 may not be the radius shown in Table 2, but rather offset towards the outer perimeter by a predetermined distance.

[0361] Figure 7d This schematically shows the heights h1, h2, h3, h4, and core radius (r) of segment 61. c A diagram showing the relationship between the radii r1, r2, r3, and r4 of the winding turns that begin to appear at the start of segment 61.

[0362] Also refer to Table 2 and Figure 7d For example, when the radius (r) of core C c When the radius is 3mm, the starting radii r1, r2, r3, and r4 of the winding turns including segments 61 with heights of 3mm (h1), 4mm (h2), 5mm (h3), and 6mm (h4) can be 6mm, 7mm, 8mm, and 9mm, respectively, and the height of segment 61 can be maintained at 6mm from a radius of 9mm to the last winding turn. Furthermore, segments 61 may not be included in winding turns with a radius less than 6mm (h1). In this embodiment, since the segment 61 with a height of 3mm (h1) closest to the core C is located at the position of the winding turn with a radius of 6mm, even if segment 61 bends towards the core C, segment 61 only covers a radial area of ​​3mm to 6mm, and the core C is not substantially obstructed. According to the α value of Formula 2, the position of segment 61 can be within the core radius (h1). c ) within 10% of the core C offset.

[0363] In another embodiment, the height of segment 61 can be increased at the same or different rates as the starting radius r of the winding turn containing segment 61 based on the core center of the electrode assembly increases.

[0364] Preferably, the height (H) of segment 61 satisfies Formula 2, and at the same time, the maximum height of segment 61 can be limited.

[0365] Figure 7e It is used to determine the maximum value (h) of the height (H) of segment 61 in the variable height region of segment 61. max Concept map.

[0366] refer to Figure 7e In the wound structure of the electrode assembly, an electrode (E1) including segment 61 faces an electrode (E2) of opposite polarity in the radial direction, separated by a diaphragm S. Both surfaces of the electrode (E1) are coated with an active material layer (E... 1，active Furthermore, both surfaces of the electrode (E2) are also coated with an active material layer (E... 2，active For electrical insulation, the end of the diaphragm S (S end ) can be obtained from the end (E) of electrode (E2) 2，end ) further extends outward to the insulation gap (W) gap The length corresponding to the electrode (E1). Furthermore, the end of electrode (E1) will not extend further outward beyond the end of electrode (E2) for electrical insulation. Therefore, an insulation gap (W) should be maintained at the lower end of the uncoated portion 43. gap The corresponding region. Furthermore, when the electrodes (E1, E2) and the diaphragm S are wound, the end of the diaphragm S (S... end This causes meandering. Therefore, in order to expose segment 61 to the outside of diaphragm S, the region (W) corresponding to the minimum meandering margin of diaphragm S must be... margin，min ) is allocated to the uncoated portion 43. Furthermore, in order to cut segment 61, a minimum cutting waste margin (W) should be allocated. scrap，min The end of the current collector foil is allocated to the segment 61. Therefore, the maximum height (h) of segment 61 in the variable height region of segment 61 is... max ) can be determined by some formulas 3. In formula 3, W foil This corresponds to the width of the current collector foil before it is cut.

[0367] <Formula 3>

[0368] h max =W foil -W scrap,min -W margin,min -W gap

[0369] Preferably, the insulation gap W gap When the first electrode is positive, the gap can be from 0.2 mm to 6 mm. Furthermore, the insulation gap W... gap When the first electrode is the negative electrode, the diameter can be from 0.1 mm to 2 mm.

[0370] Preferably, the minimum cutting waste margin W scrap，min The thickness can range from 1.5mm to 8mm. Depending on the process of forming segment 61, a minimum cutting waste margin W may not be allocated. scrap，min For example, the cutting groove 63 can be formed such that the upper edge of the segment 61 coincides with the upper edge of the current collector foil. In this case, in Formula 3, W scrap，min It can be 0.

[0371] Preferably, the minimum tortuosity margin W of the diaphragm margin，min It can be 0 to 1 mm.

[0372] In one embodiment, the minimum scrap margin (W) scrap，min The minimum tortuosity margin (W) of the diaphragm S can be 1.5 mm. margin，min The width (W) of the current collector foil before forming segment 61 can be 0.5 mm. Under these conditions, the width of the current collector foil before forming segment 61 is... foil The insulation gap is 8mm to 12mm and the insulation distance is (W). gap When the thicknesses are 0.6mm, 0.8mm, and 1.0mm, the maximum height (h) of segment 61 can be calculated using Formula 3. max ), as shown in Table 3 below.

[0373] [Table 3]

[0374]

[0375]

[0376] Considering Table 3, the maximum height (h) of segment 61 in the variable height zone of segment 61 can be determined. max The height is set to 10mm. Therefore, in the variable height region of segment 61, the height of segment 61 satisfies Formula 2 and can gradually increase or progressively increase along the radial direction of the electrode assembly within the range of 2mm to 10mm. Design conditions where the height of segment 61 exceeds 10mm may lead to expansion in the uncoated portion, thereby worsening the flatness of the uncoated portion. (Refer again...) Figure 7b The separation distance (P) of segment 61 can be adjusted within the range of 0.05 mm to 1 mm. If the separation distance (P) is less than 0.05 mm, cracks may appear in the uncoated portion 43 near the lower end of the cutting groove 63 due to stress when the electrode 60 travels during the winding process, etc. At the same time, if the separation distance (P) exceeds 1 mm, when segment 61 is bent, there may be areas where segments 61 overlap each other, which are insufficient to ensure welding strength, or empty spaces (gaps).

[0377] Meanwhile, when the current collector 41 of the electrode 60 is made of aluminum, the separation gap (P) is more preferably set to 0.5 mm or greater. When the separation gap (P) is 0.5 mm or greater, even if the electrode 60 travels at a speed of 100 mm / sec or greater under a tension of 300 gf or greater during the winding process or the like, cracks can be prevented from appearing at the bottom of the cutting groove 63.

[0378] According to the experimental results, when the current collector 41 of the electrode 60 is an aluminum foil with a thickness of 15 μm and the separation gap (P) is 0.5 mm or greater, no cracks are generated at the bottom of the cutting groove 63 when the electrode 60 travels under the above travel conditions.

[0379] like Figure 7b As shown, a cutting groove 63 is inserted between two adjacent segments 61 in the winding direction X. The cutting groove 63 corresponds to the space created by removing the uncoated portion 43. Preferably, the edges at both ends of the lower portion of the cutting groove 63 have a rounded shape. That is, the cutting groove 63 includes a generally flat bottom portion 63a and a rounded portion 63c. The rounded portion 63c connects the bottom portion 63a and the side portion 63b of the segment 61. In a variant, the bottom portion 63a of the cutting groove 63 can be replaced with an arcuate shape. In this case, the side portion 63b of the segment 61 can be smoothly connected by the arcuate shape of the bottom portion 63a.

[0380] The radius of curvature of the rounded portion 63c can be greater than 0 and less than or equal to 0.5 mm, preferably greater than 0 and less than or equal to 0.1 mm, and more preferably 0.01 mm to 0.05 mm. When the radius of curvature of the rounded portion 63c meets the above numerical range, cracks can be prevented from appearing in the lower part of the cutting groove 63 when the electrode 60 travels during winding or other processes. If the radius of curvature of the rounded portion 63c exceeds the upper limit of the above numerical range, the space at the bottom of the cutting groove 63 is reduced, which may adversely affect the impregnation of the electrolyte.

[0381] The lower interior angle (θ) of the plurality of segments 61 can increase from the core to the outer periphery. In one embodiment, the lower interior angle (θ) of the plurality of segments 61 can gradually or progressively increase from the core to the outer periphery. The lower interior angle (θ) is the angle between a straight line extending from the bottom 63a of the cutting groove 63 and a straight line extending from the side 63b of the segment 61. When the segments 61 are symmetrical in the left-right direction, the lower interior angle (θ) on the left and right sides is approximately the same.

[0382] If the radius of the electrode assembly increases, the radius of curvature also increases. If the lower interior angle (θ) of segment 61 increases with the radius of the electrode assembly, the stress generated in the radial and circumferential directions when segment 61 bends can be reduced. Furthermore, if the lower interior angle (θ) increases, the area of ​​overlap between segment 61 and the inner segment 61 and the number of overlapping layers also increase when segment 61 bends, thereby ensuring that the weld strength is uniform in the radial and circumferential directions and that a flat bending surface area can be formed.

[0383] Preferably, the lower interior angle (θ) can be determined by the radius of the winding turn where segment 61 is located and the width (D) of segment 61.

[0384] Figure 7f This is a schematic diagram used to explain the formula for determining the lower interior angle (θ) of segment 61.

[0385] refer to Figure 7f The side of segment 61 ideally coincides with line segments AE and DE, which connect the core center (E) to the two endpoints A and D of line segment AD, and line segment AD corresponds to the width (D) of segment 61.

[0386] When the side of segment 61 extends in the most ideal direction, assuming that segment EF is approximately equal to segment AE and segment DE, the lower interior angle (θ) of segment 61 can be approximately determined using the following formula 4, based on the width (D) of segment 61 and the radius (r) of the winding turn in which segment 61 is located. refer ).

[0387] <Formula 4>

[0388]

[0389] The angle in Formula 4 is the lower interior angle (θ) of segment 61. refer The ideal standard angle is θ. Simultaneously, there is a separation distance (P) between adjacent segments 61 located in the same winding turn. The length of the separation distance (P) is expressed as p. Since the separation distance (P) exists between adjacent segments 61, a tolerance of 50% can be given to the lower interior angle (θ) of the separation distance (P). That is, the width of the upper edge BC of segment 61 can be increased by a maximum of p / 2, thus forming the upper edge B'C'. The lower interior angle (θ') reflecting the tolerance can be expressed as in the following formula 5. Lower interior angle (θ) refer ) is the ideal standard angle ∠BAG, and the lower interior angle (θ') is the angle ∠B'AG' reflecting the tolerance according to the separation spacing (P). In Formula 5, H is the height of segment 61, and p corresponds to the separation spacing.

[0390] <Formula 5>

[0391]

[0392] Preferably, the lower interior angle (θ) of the segment 61 located at each winding turn of the electrode assembly can satisfy the following formula 6. Then, when the segment 61 bends toward the core center of the electrode assembly, adjacent segments 61 in the circumferential direction do not interfere with each other and can bend smoothly.

[0393] <Formula 6>

[0394]

[0395] In one embodiment, when the electrode 60 forms a wound structure with a diameter of 22 mm and a core radius of 4 mm, the lower inner angle of the segment 61 can gradually or progressively increase within the range of 60 degrees to 85 degrees in the height-variable region.

[0396] In another embodiment, the lower interior angle (θ) of the plurality of segments 61 may gradually or progressively increase from the core toward the periphery in a group or in two or more groups.

[0397] Meanwhile, the lower left and lower right interior angles of segment 61 can be different. Nevertheless, the lower interior angle (θ) on either side can be designed to satisfy the above formula 6.

[0398] Refer again Figure 7a The width of the first part B1 (d) B1 The design ensures that when segment 61 of the third part B2 bends towards the core, the core of the electrode assembly is opened outward by 90% or more based on its diameter. The width (d) of the first part B1 B1 The width (d) of the first portion B1 can be increased proportionally to the bending length of segment 61 of group 1. The bending length corresponds to the length from the bending point to the upper end of segment 61. Preferably, when electrode 60 is used to manufacture an electrode assembly for a cylindrical battery with a form factor of 4680, the width (d) of the first portion B1 is increased proportionally to the bending length of segment 61 of group 1. B1 The setting can be set from 180mm to 350mm.

[0399] The bending point of segment 61 can be set at the line passing through the lower end of the cutting groove 63 or at a point spaced upwards from that line by a predetermined distance. When segment 61 bends towards the core at a point spaced a certain distance from the lower end of the cutting groove 63, the segments can overlap better in the radial direction. When segment 61 bends, the segment with the center of the core on the outside presses down on the segment on the inside. At this time, if the bending point is spaced a predetermined distance from the lower end of the cutting groove 63, the inner segment is pressed down by the outer segment along the winding axis, and the segments overlap better. The separation distance of the bending point can preferably be 1 mm or less. Since the minimum height of segment 61 is 2 mm, the ratio of the separation distance of the bending point to the minimum height can be 50% or less.

[0400] In one embodiment, the width of each segment group can be designed to form the same winding turn constituting the electrode assembly. Here, when the electrode 60 is in a wound state, the winding turns can be counted based on the end of the first portion B1.

[0401] In another variation, the width of each segment group can be designed to constitute at least one winding turn of the electrode assembly.

[0402] In another variation, the width and / or height and / or separation spacing of segments 61 belonging to the same segment group may gradually and / or progressively and / or irregularly increase or decrease within the group or between adjacent groups.

[0403] Groups 1 to 8 are merely embodiments of the segment groups included in Part B2. The number of groups, the number of segments 61 included in each group, and the width of the group can preferably be adjusted such that the segments 61 overlap in multiple layers to distribute stress as much as possible during the bending process of the uncoated portion 43 and to adequately ensure the welding strength with the current collector.

[0404] In another variation, the height of the second part B3 can be gradually or progressively reduced, as in the first and second embodiments.

[0405] In another variation, the segmental structure of the third portion B2 may extend to the second portion B3 (see dashed lines). In this case, the second portion B3 may also include multiple segments, just like the third portion B2. Preferably, the segmental structure of the second portion B3 may be substantially the same as the outermost segment group structure of the third portion B2. In this case, the segments included in the second portion B3 and the third portion B2 may have substantially the same width, height, and separation spacing. In a variation, the width and / or height and / or separation spacing of the segments in the second portion B3 may be greater than the width and / or height and / or separation spacing of the third portion B2. Optionally, the last winding turn of the second portion B3 may have a shape with segments removed.

[0406] In Part B2, the region (groups 1 to 7) in which the height of segment 61 gradually increases based on the winding direction of electrode 60 is defined as the segment height variable region, and the final segment group (group 8) can be defined as the height uniform region in which the height of the segment is uniformly maintained.

[0407] That is, in part B2 of the third section, when the height of segment 61 gradually increases from h1 to h... N At that time, the height is h1 to h N-1 The region of segment 61 (where N is the height exponent and a natural number greater than 2) corresponds to the height-variable zone, and is arranged with height h. N The region of segment 61 corresponds to the height uniformity region. The ratio of the height variable region and the height uniformity region to the length of electrode 60 in the winding direction will be described later with reference to specific embodiments.

[0408] When electrode 60 is used to manufacture the electrode assembly of a cylindrical battery with a form factor of 4680, the width (d) of the first portion B1 B1 The width of group 1 can be from 180mm to 350mm. The width of group 1 can be 35% to 40% of the width of the first part B1. The width of group 2 can be 130% to 150% of the width of group 1. The width of group 3 can be 120% to 135% of the width of group 2. The width of group 4 can be 85% to 90% of the width of group 3. The width of group 5 can be 120% to 130% of the width of group 4. The width of group 6 can be 100% to 120% of the width of group 5. The width of group 7 can be 90% to 120% of the width of group 6. The width of group 8 can be 115% to 130% of the width of group 7. The width of the second part B3 (d...) B3 The width can be 180mm to 350mm, similar to the width of part B1 in the first section.

[0409] In this embodiment, the widths of groups 1 to 8 do not exhibit a pattern of constant increase or decrease. This is because the segment widths gradually increase from group 1 to group 8, but the number of segments included in a group is limited to an integer, and the electrode thickness has a slight deviation along the winding direction. Therefore, in a specific segment group, the number of segments can be reduced. Thus, the width of the group can exhibit an irregular variation pattern from the core to the outer periphery, as shown in the embodiments above. Of course, groups 1 to 8 can also be designed to exhibit a pattern of constant increase in width by reducing the segment widths.

[0410] That is, assuming that the widths of each of the three segment groups that are continuously adjacent to each other in the circumferential direction of the electrode assembly are W1, W2 and W3 respectively in the winding direction, the electrode assembly may include a combination of segment groups in which W3 / W2 is less than W2 / W1.

[0411] In a specific embodiment, groups 4 to 6 correspond to the above situation. 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%.

[0412] According to another variation, when the uncoated portion 43 of electrode 60 has multiple segment groups, the segment group (G k-1 G k G k+1 They can be spaced apart by a group separation interval Db in the winding direction X, such as Figure 7g As shown in the diagram, the height of the uncoated portion corresponding to the group separation interval Db can be approximately the same as the height of the first portion B1 or the second portion B3.

[0413] In one respect, from the core toward the outer periphery, the width (D) of the segment 61 in the winding direction belonging to each segment group can be gradually increased for each group, the height (H) of the segment 61 can also be gradually increased for each group, and the lower interior angle (θ) can also be gradually increased for each group.

[0414] On the other hand, the width Dg of the segment group in the winding direction can gradually or progressively increase from the core towards the outer periphery. The width Dg in the winding direction can be increased for each segment group or for every two or more segment groups.

[0415] On the other hand, the interval Db between segment groups can increase gradually or progressively from the core toward the periphery. The group separation interval Db can be increased for each segment group or for every two or more segment groups.

[0416] When adjusting the width Dg and the group separation interval Db in the winding direction of the segment group, as follows: Figure 7h and Figure 7i As shown, segments 61 are arranged radially in some regions to form one or more segment alignment portions 61g. The segment alignment portions 61g are groups of segments (G) aligned along the radial direction of the electrode assembly JR. k-1 G k G k+1 A set of ).

[0417] like Figure 7j As shown, if the segment group (G) included in the segment alignment part 61g is connected by a line... k-1 G k G k+1 The two ends of the core C and the center O of the core C form a fan shape for each segment group.

[0418] Preferably, the segment alignment part 61g includes a segment group (G) k-1 G k G k+1The circumferential angle (δ) of the sector shape can be substantially the same in size and range. If the electrode has a thickness tolerance, the segment group (G) included in the segment alignment part 61g k-1 G k G k+1 The inscribed angles (δ) of the circles can have approximately the same size, and the range of the inscribed angles (δ) can be different.

[0419] The inscribed angle (δ) can be 20 degrees or greater, optionally 25 degrees or greater, optionally 30 degrees or greater, optionally 35 degrees or greater, or optionally 40 degrees or greater.

[0420] When segment 61, included in segment alignment portion 61g, bends toward core C, a bending surface region F is formed on a plane substantially perpendicular to the winding axis, such as... Figure 7h and Figure 7i As shown in the figure. In addition, an electrolyte impregnation portion Ep is formed between adjacent bent surface regions F in the circumferential direction.

[0421] Since the bent structure of segment 61 is not present in the electrolyte impregnation section Ep, the ends of the diaphragm and the active material layer of the electrode are exposed to the outside when viewed in the winding axis direction (i.e., the direction of electrolyte injection). Therefore, when electrolyte is injected along the winding axis direction of the electrode assembly JR, the electrolyte rapidly penetrates into the electrode assembly JR while directly contacting the ends of the diaphragm and the active material layer, thereby increasing the electrolyte impregnation rate.

[0422] Additionally, as mentioned above... Figure 7a To further improve the electrolyte impregnation rate, the end SL of the diaphragm SP in the winding axis direction is preferably spaced from the baseline DL by a distance corresponding to 30% or less of the minimum segment height Ha. In this case, since the electrolyte is also impregnated through the bottom of the cutting groove 63, the electrolyte impregnation rate can be further improved, and the uniformity of electrolyte impregnation can also be improved.

[0423] Figure 7h The structure is shown with the bent surface regions F spaced 90 degrees apart, and Figure 7i A structure is shown where the bent surface regions F are spaced 180 degrees apart. Here, the arrangement angle of the bent surface regions F can be defined as the angle between straight lines passing through the geometric center of a pattern that approximately corresponds to the edge shape of the bent surface region F. That is, when the line connecting the center of the electrode assembly and the geometric center of the pattern that approximately corresponds to the edge shape of the bent surface region F is defined as the angle measurement line, the angle measured using the angle measurement lines of adjacent bent surface regions F in the circumferential direction can be regarded as the arrangement angle of the bent surface regions F. In one embodiment, the geometric center of the pattern corresponding to the edge of the bent surface region F can be the centroid.

[0424] The segment group constituting the bent surface region F can be arranged radially from the core center of the electrode assembly JR. Furthermore, the uncoated portion of the wound portion constituting the electrolyte impregnation section Ep can also be arranged radially from the core center of the electrode assembly JR. The circumferential length of the segment group included in the bent surface region F gradually increases from the core towards the outer periphery. Additionally, the circumferential length of the uncoated portion of the wound portion constituting the electrolyte impregnation section Ep also increases from the core towards the outer periphery. The shape of the pattern formed by the edges of the bent surface region F resembles a fan shape with the central portion removed.

[0425] Figure 7h The electrode assembly JR shown is suitable for welding current collectors, wherein four welding zones are radially designed at 90-degree intervals, and Figure 7i The electrode assembly JR shown is suitable for welding current collectors, with two welding zones designed radially at 180-degree intervals.

[0426] The above embodiments illustrate a structure with four bent surface areas (welding areas) F spaced at 90-degree intervals or two bent surface areas F spaced at 180-degree intervals, but this disclosure is not necessarily limited to this. For example, various radial arrangements can be used, such as 12 bent surface areas spaced at 30-degree intervals, 8 bent surface areas spaced at 45-degree intervals, 6 bent surface areas spaced at 60-degree intervals, 5 bent surface areas spaced at 72-degree intervals, and 3 bent surface areas spaced at 120-degree intervals.

[0427] In another variation, the bent surface area F may not be radially arranged, but rather formed in various shapes at a location corresponding to the area where the current collector is to be welded. The bent surface area F can have geometries such as squares, rectangles, parallelograms, or trapezoids. The various shapes of the bent surface area F can be determined by adjusting the width Dg of the segment group in the winding direction and the separation distance Db between the segment groups.

[0428] Meanwhile, when the segment groups are designed to be spaced apart along the winding direction X so that bending surface areas F are not formed in some regions, positional deviations of the segment groups may occur from the core towards the outer periphery due to electrode thickness variations. These positional deviations of the segment groups gradually accumulate towards the outer periphery.

[0429] According to one embodiment of this disclosure, in order to ensure that the area where the current collector can be welded is guaranteed even if the positional deviation of the segment group accumulates as it gets closer to the outer circumference, the width of the segment group can gradually or progressively increase from the core toward the outer circumference, thereby forming a fan-shaped bent surface area F.

[0430] Therefore, even if the shape of the bent surface region F is deformed due to the accumulation of positional errors of the segment group toward the outer periphery (see... Figure 7i (When the electrode assembly is wound clockwise, the shape of the bent surface area F also deforms clockwise), as in... Figure 7iAs can be seen in the deformation area indicated by the arrow, the predetermined welding area W can still be adequately guaranteed.

[0431] The circumferential angle of the sector forming the bent surface region F can be determined based on the amount of accumulated error (see [reference]). Figure 7j (δ in the figure). In one embodiment, a sector shape with a circumferential angle of approximately 30 degrees is illustrated. As the circumferential angle of the sector shape increases, the amount of allowable cumulative error may increase. However, in return, the area of ​​the electrolyte immersion portion Ep, where the bending surface region F is not formed, decreases.

[0432] Meanwhile, if the area corresponding to the width of the segment group consists of a single segment, the circumferential angle of the fan-shaped area corresponding to the bending surface area F is relatively large. When the segment bends, deformation occurs in the circumferential direction, and the segment may not be able to bend smoothly. Therefore, in this disclosure, when the bending surface area F is designed as a fan shape, the uncoated portion in the area corresponding to the fan shape of the winding turn is formed into a segment group, and the bending of the segments belonging to the corresponding group allows the uncoated portion to bend smoothly.

[0433] According to this embodiment, when the circumferential angle of the region of the winding turn located within the fan-shaped area corresponding to the bending surface area F exceeds 30 degrees, the uncoated portion in the region of the winding turn is divided into at least two segments, such that the circumferential angle in the region of the winding turn corresponding to each segment becomes less than 30 degrees.

[0434] In this disclosure, the shape of segment 61 can vary in different ways.

[0435] Figure 8a This is a plan view showing the structure of the electrode 70 according to the fifth embodiment of this disclosure.

[0436] refer to Figure 8a Except for the shape of segment 61', the electrode 70 of the fifth embodiment is substantially the same as the electrode 70 of the previous embodiment. Therefore, unless otherwise described, the configuration of the fourth embodiment can be applied equivalently to the fifth embodiment.

[0437] Segment 61' has a geometric shape with approximately equal upper and lower widths. Preferably, segment 61' may have a rectangular shape.

[0438] The corners or vertices of a rectangle can be rounded or beveled, but not sharp.

[0439] Figure 8b This is a diagram showing the definition of the width, height, and separation spacing of segment 61'.

[0440] refer to Figure 8bThe width (D), height (H), and separation spacing (P) of segment 61' can be set to prevent the uncoated portion 43 from tearing during bending and to prevent abnormal deformation of the coated portion 43, while sufficiently increasing the number of overlapping layers of the uncoated portion 43 to improve the welding strength with the current collector. Abnormal deformation refers to the uncoated portion below the bending point not maintaining a straight state and deforming irregularly when falling.

[0441] The width (D) of segment 61' is defined as the length between two points where two straight lines extending from both sides of segment 61' intersect with a straight line extending from the bottom 63a of the cutting groove 63. The height (H) of segment 61' is defined as the shortest distance between the uppermost edge of segment 61' and a straight line extending from the bottom 63a of the cutting groove 63. The separation distance (P) of segment 61' is defined as the length between two points where a straight line extending from the bottom 63a of the cutting groove 63 intersects with a straight line extending from both sides 63b connected to the bottom 63a. When the sides 63b and / or the bottom 63a are curved, the straight lines can be replaced by tangents extending from the sides 63b and / or the bottom 63a at the intersection of the sides 63b and the bottom 63a.

[0442] Preferably, the conditions regarding the width (D), height (H), and separation distance (P) of segment 61' are largely the same as those in the fourth embodiment described above, and therefore will not be described again. However, since segment 61' has a rectangular shape, the lower interior angle of segment 61' can be kept constant at 90 degrees.

[0443] Furthermore, the electrode 70 according to the fifth embodiment may also have a plurality of segment groups (G) arranged along the winding direction X at a separation interval Dg. k-1 G k G k+1 ),like Figure 8c As shown in the image. In this case, refer to... Figure 7h , Figure 7i and Figure 7j The described implementation methods can be applied substantially equivalently to winding. Figure 8c The electrode assembly manufactured by electrode 70 shown. That is, except that the shape of the segments included in the segment group changes from trapezoidal to rectangular, the reference can be applied in a substantially the same way. Figure 7h , Figure 7i and Figure 7j The described implementation method.

[0444] In the fourth and fifth embodiments, when the third part B2 and the second part B3 include multiple segments 61, 61', the shape of each segment 61, 61' can be varied in various ways.

[0445] Preferably, the segments can be deformed into various shapes if at least one of the following conditions is met.

[0446] Condition 1: The width of the lower part is greater than the width of the upper part.

[0447] Condition 2: The width of the lower part is the same as the width of the upper part.

[0448] Condition 3: The width remains uniform from the top to the bottom.

[0449] Condition 4: The width decreases from the top to the bottom.

[0450] Condition 5: The width decreases from the bottom to the top and then increases.

[0451] Condition 6: The width increases from the bottom to the top and then decreases.

[0452] Condition 7: The width increases from the bottom to the top and then remains uniform.

[0453] Condition 8: The width decreases from the bottom to the top and remains constant.

[0454] Condition 9: The interior angle on one side of the lower part is the same as the interior angle on the other side.

[0455] Here, the interior angle can be defined as the angle formed by the side portion of a segment based on the width direction of the lower portion of the segment. When the side portion is curved, the interior angle is defined as the angle between the tangent drawn at the lowest point of the curve and the width direction of the lower portion of the segment.

[0456] Condition 10: The interior angles on one side of the lower part are different from the interior angles on the other side.

[0457] Condition 11: The interior angles on one side of the lower part and the interior angles on the other side of the lower part are acute, right, or obtuse, respectively.

[0458] Condition 12: Based on the symmetry of the winding axis direction in the left and right directions.

[0459] Condition 13: Based on the asymmetry of the winding axis direction in the left and right directions.

[0460] Condition 14: The side portion is straight.

[0461] Condition 15: The side portion is curved.

[0462] Condition 16: The lateral portion bulges outward.

[0463] Condition 17: The lateral portion convexes inward.

[0464] Condition 18: The corners of the upper and / or lower parts have a structure where straight lines intersect.

[0465] Condition 19: The corners of the upper and / or lower parts have a structure where a straight line intersects a curve.

[0466] Condition 20: The corners of the upper and / or lower parts have a structure where curves intersect.

[0467] Condition 21: The corners of the upper and / or lower parts have a rounded structure.

[0468] Figure 9 This is an exemplary diagram showing the shape of a segment according to a variant of this disclosure.

[0469] As shown in the figure, the segment can have various geometries, where the dashed line connecting the bottom portions of the two cutting grooves is the base. The geometry has a structure connecting at least one straight line, at least one curve, or a combination thereof. In one embodiment, the segment can have a polygonal shape, a rounded shape, or a combination thereof.

[0470] Specifically, the segment can have a trapezoidal shape that is symmetrical from left to right. A trapezoidal shape with left and right asymmetry parallelogram shape triangle shape pentagonal shape arc shape Or oval shape

[0471] Because the shape of the segment is not limited to Figure 9 The shape shown can therefore be transformed into other polygonal shapes, other rounded shapes, or combinations thereof to satisfy at least one of conditions 1 to 21 above.

[0472] In the polygonal shape of the segment as well as In the middle, the corners of the upper and / or lower parts can have a shape with intersecting straight lines or a rounded shape (see Shape). (Enlarged view of the corners of the upper and / or lower parts).

[0473] In the polygonal shape of the segment as well as and the curve shape of the segment and In a geometric figure, the interior angles (θ1) on one side and (θ2) on the other side can be the same or different, and these angles can be acute, right, or obtuse, respectively. An interior angle is the angle where the base and lateral parts of a geometric figure intersect. When the lateral part is a curve, a straight line can be replaced by a tangent extending from the point where the base and lateral parts intersect.

[0474] The shape of the side portion of a segment with a polygonal shape can vary in a variety of ways.

[0475] In one embodiment, segment shape The side portion can be transformed into an outwardly convex curve (such as a shape). ), or transform into inwardly curved segments (such as shapes) or ).

[0476] In another embodiment, the segment shape The side portion can be transformed into, for example, the shape or A curved straight line that curves inward into the segment. Although not shown, the segment shape... The side portion can be transformed into an outwardly convex bent straight line.

[0477] The segmental shapes vary differently in the lateral portion. as well as In the lower part, the interior angle (θ1) on one side and the interior angle (θ2) on the other side can be the same or different, and the interior angle (θ1) on one side and the interior angle (θ2) on the other side of the lower part can be any one of acute angle, right angle or obtuse angle.

[0478] The width of a segment can have various patterns of variation from bottom to top.

[0479] In one embodiment, the width of the segment can remain uniform from bottom to top (shape). In another embodiment, the width of the segment may gradually decrease from bottom to top (shape). as well as In yet another embodiment, the width of the segment may gradually decrease from bottom to top and then increase (shape). and In yet another embodiment, the width of the segment may gradually increase from bottom to top and then decrease (shape). In yet another embodiment, the width of the segment may gradually decrease from bottom to top, and then remain uniform (shape). Although not shown, the width of the segment can gradually increase from bottom to top and remain constant.

[0480] At the same time, Figure 9 In the segment shapes shown, the polygonal shapes with flat tops can be rotated 180 degrees. In one embodiment, when the segment shape... or When rotated 180 degrees, the width of the segment can gradually increase from bottom to top. In another embodiment, if the segment shape... Rotating 180 degrees allows the segment width to remain uniform from bottom to top, and then gradually increase.

[0481] In the above-described embodiments (variations), according to another aspect of this disclosure, the shapes of segments 61 and 61' can be varied depending on the region of the third part B2. In one embodiment, rounded shapes that facilitate stress distribution (e.g., semicircles, semi-ellipses, etc.) can be applied to regions of stress concentration, and polygonal shapes with the widest possible area (e.g., squares, trapezoids, parallelograms, etc.) can be applied to regions of relatively low stress.

[0482] On the other hand, they can have different shapes individually, in groups, or in two or more groups, in one direction parallel to the winding direction of the electrode assembly.

[0483] In another embodiment (variant), the segmental structure of the third part B2 can also be applied to the first part B1. However, when the segmental structure is applied to the first part B1, when the segments 61, 61' of the third part B2 are bent according to the radius of curvature of the core, a reverse forming phenomenon may occur, where the ends of the first part B1 bend towards the outer periphery. Therefore, even if the first part B1 does not have segments, or even if a segmental structure is applied, it is desirable to adjust the width and / or height and / or separation distance of the segments 61, 61' as much as possible, taking into account the radius of curvature of the core, so that reverse forming does not occur.

[0484] The height of the segment that can be reverse-formed can be less than about 3 mm. Furthermore, if the segment height is less than 2 mm, interference may occur between the segment and the diaphragm, making bending difficult. Additionally, if the segment height is less than 4 mm, the segment welding process may be unsuccessful. Preferably, the minimum height (H) of the segment designed for bending is... min It can be 5mm.

[0485] refer to Figure 8a and Figure 9 Based on the baseline DL, if the height in the uncoated portion is equal to or greater than the minimum bendable height (H) min In segments (e.g., 2mm, 3mm, 4mm, or 5mm), if the end SL of the diaphragm in the width direction exists within ±30% of the height Ha of the minimum segment, the impregnation performance can be greatly enhanced. That is, when determining the minimum segment that defines the position of the end SL of the diaphragm in the width direction, segments that may lead to reverse forming or non-bending segments can be excluded.

[0486] From another perspective, based on the baseline DL, if the end SL of the diaphragm in the width direction exists in the uncoated portion, the minimum segment height Ha and the minimum bendable height (H) are considered. min The larger height {max(Ha, H)} min Within ±30% of the range, the impregnation performance can be greatly enhanced.

[0487] From another perspective, based on the baseline DL, if the end SL of the diaphragm in the width direction exists at the minimum bendable height (H)... min Within ±30% of the baseline DL, the impregnation performance of the electrolyte can be greatly enhanced. This can be within the range of DL ±1.5mm, DL ±1.2mm, DL ±0.9mm, or DL ​​±0.6mm.

[0488] According to another aspect of this disclosure, after the electrodes 60 and 70 are wound into an electrode assembly, the segments exposed on the upper and lower portions of the electrode assembly can overlap in several layers along the radial direction of the electrode assembly to form a bent surface region.

[0489] It should be noted in advance that the following description of the bent surface area can be applied in a substantially similar manner to the bent surface area formed by the segments of the bent segment alignment part.

[0490] Figure 10a This is a schematic diagram showing a cross-section of the bent surface region F formed when these segments 61 are bent toward the core C of the electrode assembly JR. Figure 10a In the diagram, based on the winding axis of the electrode assembly 80, only the left side shows a cross-section of the bent surface region F. The bent surface region F can be formed in both the upper and lower portions of the electrode assembly 80. Figure 10b This is a schematic top perspective view of an electrode assembly 80 having a bent surface region F.

[0491] refer to Figure 10a and Figure 10b The bent surface region F has a structure in which segments 61 overlap in multiple layers in the direction of the winding axis. The overlapping direction is the winding axis direction Y. Region ① is a segment skipping region (first part B1) without segments, and regions ② and ③ are regions containing winding turns containing segments 61 with separation gaps between them. Region ② is a height-variable region where the height of segments 61 varies, and region ③ is a height-uniform region where the height of segments remains uniform up to the outer periphery of the electrode assembly. As will be described later, the lengths of regions ② and ③ in the radial direction can be variable. Meanwhile, the uncoated portion (second part B3) included in at least one winding turn including the outermost winding turn may not include the segment structure. In this case, the second part B3 can be excluded from this region.

[0492] In region ②, the height of segment 61 can be within the radius region r1 to r of electrode assembly 80. N From the minimum height h1 (=h min Gradually change to the maximum height h N (=h maxThe variable height zone for the height change of segment 61 is from r1 to r. N From the radius r of electrode assembly 80 N Up to radius R, the height of segment 61 is uniformly maintained at h. N Uniform height refers to a height deviation within 5%.

[0493] At any radial location in regions ② and ③, the number of segments 61 stacked varies depending on the radius. Furthermore, the number of segments 61 stacked can be determined based on the width of region ②, the minimum height (h1) and maximum height (h2) of the segments in the variable height zone of segment 61. N-1 The number of segments 61 is changed by the height variation (Δh) of segment 61. The number of segments stacked is the number of segments that intersect the imaginary line when an imaginary line is drawn along the winding axis at any radial position of the electrode assembly 80.

[0494] Preferably, the number of segments 61 stacked at each location in the bent surface region F can be optimized according to the required welding strength of the current collector by adjusting the height, width, and separation spacing of the segments 61 according to the radius of the winding turn containing the segments 61.

[0495] First, in the variable height region (②) of segment 61, when the minimum height (h1) of the segments is the same, the stacking number of segments 61 will be described through a specific implementation method to illustrate how it varies with the maximum height (h1) of segment 61. N-1 The change occurs along the radial direction of the bent surface region F due to the change in ) ).

[0496] Electrode assemblies according to embodiments 1-1 to 1-7 are prepared. These electrode assemblies have a radius of 22 mm and a core diameter of 4 mm. The positive and negative electrodes included in the electrode assembly have… Figure 7a The electrode structure shown is such that the segments have a trapezoidal shape. The second portion B3 of both the positive and negative electrodes does not contain any segments. The length of the second portion B3 is 3% to 4% of the total length of the electrode. Figure 2 The method described herein winds a positive electrode, a negative electrode, and a separator. The number of winding turns is between 48 and 56, while in these embodiments, the number of winding turns is 51. The thicknesses of the positive electrode, negative electrode, and separator are 149 μm, 193 μm, and 13 μm, respectively. The thicknesses of the positive and negative electrodes include the thickness of the active material layer. The thicknesses of the positive and negative current collectors are 15 μm and 10 μm, respectively. The lengths of the positive and negative electrodes in the winding direction are 3948 mm and 4045 mm, respectively.

[0497] In each embodiment, the minimum height of segment 61 is set to 3 mm, such that the variable height zone (②) of segment 61 starts from a radius of 5 mm. Furthermore, in each embodiment, the height of segment 61 increases by 1 mm for every 1 mm increase in radius, and the maximum height of segment 61 varies from 4 mm to 10 mm.

[0498] Specifically, in Embodiment 1-1, the height variable area (②) of segment 61 is 5mm to 6mm, and the height of segment 61 can be changed from 3mm to 4mm. In Embodiment 1-2, the height variable area (②) of segment 61 is 5mm to 7mm, and the height of segment 61 can be changed from 3mm to 5mm. In Embodiment 1-3, the height variable area (②) of segment 61 is 5mm to 8mm, and the height of segment 61 can be changed from 3mm to 6mm. In Embodiment 1-4, the height variable area (②) of segment 61 is 5mm to 9mm, and the height of segment 61 can be changed from 3mm to 7mm. In Embodiment 1-5, the height variable area (②) of segment 61 is 5mm to 10mm, and the height of segment 61 can be changed from 3mm to 8mm. In Embodiment 1-6, the height variable area (②) of segment 61 is 5mm to 11mm, and the height of segment 61 can be changed from 3mm to 9mm. In embodiments 1-7, the height variable region (②) of segment 61 is 5 mm to 12 mm, and the height of segment 61 can be varied from 3 mm to 10 mm. In embodiments 1-1 to 1-7, the height of segment 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 (10 mm) of segment 61 located at a radius from 12 mm to 22 mm is uniform. Meanwhile, in the electrode assembly of the comparative example, the height of segment 61 is maintained at a single height of 3 mm from a radius of 5 mm to 22 mm.

[0499] Figure 10c This is a graph showing the results of counting the number of segments stacked in the radial direction in the bent surface region F of the positive electrode formed at the upper portion of the electrode assembly according to embodiments 1-1 to 1-7 and the comparative example. The bent surface region of the negative electrode also shows substantially the same results. 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 stacks counted at each radial point; this also applies in the same way to what will be explained later. Figure 10d and Figure 10e .

[0500] refer to Figure 10cThe uniform stacking number region b1 of segments is shown in both Embodiments 1-1 to 1-7 and Comparative Example 1. The uniform stacking number region b1 is the radial region of the flat area in each graph. The length of the uniform stacking number region b1 increases as the maximum height of the segment decreases, and the uniform stacking number region b1' of the Comparative Example is the longest. Simultaneously, the number of segments stacked increases with the maximum height of the segment (h). N As the segment increases, the height increases. That is, at the maximum height of the segment (h) N As the height of the segment increases, the width of the variable height region (②) increases, resulting in an increase in the number of segments stacked, but the width of the uniform stacking region b1 decreases. Outside the uniform stacking region b1, a stacking number reduction region b2 appears, where the number of segments stacked decreases with increasing radius. The stacking number reduction region b2 is a radial region where the number of segments stacked decreases with increasing electrode assembly radius. The uniform stacking region b1 and the stacking number reduction region b2 are adjacent and complementary in the radial direction. That is, when the length of one region increases, the length of the other region decreases. Furthermore, in the stacking number reduction region b2, the number of segments stacked decreases proportionally to the distance from the uniform stacking region b1.

[0501] From the perspective of the number of stacked segments, in embodiments 1-1 to 1-7, the number of stacked segments in the uniform stacking area b1 is 10 or more. The area with 10 or more stacked segments can be set as an ideal welding target area. The welding target area is an area where at least a portion of the current collector can be welded.

[0502] In embodiments 1-1 to 1-7, the uniform stacking area b1 starts from the radius point of the segment height variable area (②). That is, the height variable area (②) starts from a radius of 5 mm and extends towards the outer periphery.

[0503] Table 4 below shows the following calculation results for the positive electrode in Embodiments 1-1 to 1-7 and Comparative Example 1: Segment skipping region (c, Figure 10a The ratio of the length of ①) to the radius (ba) of the electrode assembly excluding the core; the ratio of the length of the uniform stacking area b1 to the length (f) from the radius point (5mm) starting from the uniform stacking area to the outermost point (22mm) of the electrode assembly (e / f); the ratio of the length (d) of the segment height variable area to the length (f) from the radius point (5mm) starting from the uniform stacking area to the outermost point (22mm) of the electrode assembly (d / f); the ratio of the length of the electrode area corresponding to the segment skipping area (first part B1) to the total length of the electrode (h); the ratio of the length of the electrode area corresponding to the height variable area to the total length of the electrode (i); and the ratio of the length of the electrode area corresponding to the height uniform area to the total length of the electrode (j), etc.

[0504] Except for the negative electrode, which shows a difference of 0.1% to 1.2% with respect to parameter h, the other parameters are largely the same as those for the positive electrode. The sum of the proportions h, i, and j is slightly different from 100%. This is because there is a region without segments in the second portion B3, which corresponds to the uncoated portion of the outer periphery of the electrode. For example, in Embodiment 1-1, there are no segments in the second portion B3, which corresponds 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 longitudinal direction of the electrode before it is wound into an electrode assembly. Furthermore, the parameters corresponding to the ratios (%) are values ​​rounded to a decimal place. These aspects are largely the same in Tables 5 and 6, which will be explained later.

[0505] [Table 4]

[0506]

[0507] Referring to embodiments 1-1 to 1-7 in Table 4, the number of stacked segments is 11 to 27, and the ratio (d / f) of the height-variable region (d) to the radial region f containing segments is 6% to 41%. Furthermore, the ratio (e / f) of the uniform stacking region (e) to the radial region f containing segments is 47% to 82%. Additionally, there is a segment skipping region (c... Figure 10a The ratio (c / (ba)) of ①) to the radius (ba) of the electrode assembly (excluding the core) is 15%. Furthermore, the ratio of the length of the electrode area corresponding to the segment skipping area (first part B1) to the total length of the electrode is 6%, the ratio of the length of the electrode area corresponding to the height variable area to the total length of the electrode is 3% to 32%, and the ratio of the length of the electrode area corresponding to the height uniform area to the total length of the electrode is 59% to 87%. For all embodiments 1-1 to 1-7, the number of stacks (g) in the stack number uniform area is 10 or more. The stack number uniform area (e) decreases as the height variable area (d) of the segment increases, but the number of segments stacked (g) increases in the stack number uniform area (e). Preferably, the stack number uniform area (e) in which the number of segments stacked (g) is 10 or more can be set as the welding target area.

[0508] In cylindrical batteries with form factors of 1865 and 2170, the radius of the electrode assembly is approximately 9 mm to 10 mm. Therefore, for conventional cylindrical batteries, the radial length of the segment region (f) cannot be guaranteed to be at the level of 17 mm as in embodiments 1-1 to 1-7, and the length of the uniform stacking area (e) cannot be guaranteed to be at the level of 8 mm to 14 mm. This is because, in conventional cylindrical batteries, when the core radius is designed to be 2 mm (the same as in embodiments 1-1 to 1-7), the radial region where segments can be set is approximately only 7 mm to 8 mm. Furthermore, in conventional cylindrical batteries, the length of the electrode in the winding direction is approximately 600 mm to 980 mm. This short electrode length is only about 15% to 24% of the electrode length used in embodiments 1-1 to 1-7 (3948 mm for the positive electrode and 4045 mm for the negative electrode). Therefore, the numerical ranges of parameters h, i, and j cannot be easily derived from the design specifications of conventional cylindrical batteries.

[0509] Next, when the maximum height of the segment (h) N In the segment height variable region ( Figure 10a When the same applies to section ②, the specific implementation method will explain how the number of stacked segments changes in the radial direction of the bent surface area F according to the change of the minimum height (h1) of the segment.

[0510] The electrode assemblies in embodiments 2-1 to 2-5 have a radius of 22 mm and a core C diameter of 4 mm. In the height-variable region of segment 61 ( Figure 10a In section ②), the minimum height (h1) is 4mm, and the maximum height (h) is... N The height of the segment is varied from 6mm to 10mm in increments of 1mm. Therefore, in the electrode assemblies of embodiments 2-1 to 2-5, the height of the segment is variable (…). Figure 10a The widths of ②) are 2mm, 3mm, 4mm, 5mm and 6mm respectively, and the segment skipping area ( Figure 10a ①) is a radial region with a radius of 2mm to 6mm.

[0511] The electrode assemblies in embodiments 3-1 to 3-4 have a radius of 22 mm and a core C diameter of 4 mm. In the height-variable region of segment 61 ( Figure 10a In section ②), the minimum height (h1) is 5mm, and the maximum height (h) is... N The segment height is varied from 7mm to 10mm in 1mm increments. Therefore, in the electrode assemblies of embodiments 3-1 to 3-4, the segment height variable area ( Figure 10a The widths of ②) are 2mm, 3mm, 4mm and 5mm respectively, and the segment skipping area ( Figure 10a ①) in the figure is a radial region with a radius of 2 mm to 7 mm.

[0512] The electrode assemblies in embodiments 4-1 to 4-3 have a radius of 22 mm and a core C diameter of 4 mm. In the height-variable region of segment 61 ( Figure 10a In section ②), the minimum height (h1) is 6mm, and the maximum height (h) is... N The height of the segment is varied from 8mm to 10mm in increments of 1mm. Therefore, in the electrode assemblies of embodiments 4-1 to 4-3, the height of the segment is variable (…). Figure 10a The widths of ②) are 2mm, 3mm and 4mm respectively, and the segment skipping area ( Figure 10a ①) in the figure is a radial region with a radius of 2 mm to 8 mm.

[0513] The electrode assemblies in embodiments 5-1 and 5-2 have a radius of 22 mm and a core C diameter of 4 mm. In the height-variable region of segment 61 ( Figure 10a In section ②), the minimum height (h1) is 7mm, and the maximum height (h) is... N The height of the segment is varied from 9mm to 10mm in increments of 1mm. Therefore, in the electrode assemblies of embodiments 5-1 to 5-2, the height of the segment is variable (…). Figure 10a The widths of ②) are 2mm and 3mm respectively, and the segment skipping area ( Figure 10a ①) in the figure is a radial region with a radius of 2 mm to 9 mm.

[0514] Figure 10d This is a graph showing the results of counting the number of segments stacked in the radial direction in the bent surface region F of the positive electrode formed at the upper portion of the electrode assembly according to embodiments 2-1 to 2-5, embodiments 3-1 to 3-4, embodiments 4-1 to 4-3, and embodiments 5-1 and 5-2. The bent surface region of the negative electrode also shows substantially the same results.

[0515] exist Figure 10d In the figure, graph (a) shows the result of counting the number of segments stacked in the radial direction in the bent surface area F of embodiments 2-1 to 2-5, graph (b) shows the result of embodiments 3-1 to 3-4, graph (c) shows the result of embodiments 4-1 to 4-3, and graph (d) shows the result of embodiments 5-1 to 5-2.

[0516] refer to Figure 10d In all embodiments, a uniform stacking region b1 is present. This uniform stacking region b1 is the radial region of the flat area in the graph. When the minimum height (h1) of the segments is the same, the length of the uniform stacking region b1 increases with the maximum height (h2) of the segments. N ) decreases and increases. Furthermore, when the maximum height of the segment (h) decreases...N At the same time, the length of the uniform stacking region b1 increases as the minimum height (h1) of the segment decreases. Simultaneously, within the uniform stacking region b1, the number of segments stacked increases with the maximum height (h1) of the segment. N The number of stacks increases as the number of stacks increases. Furthermore, in these embodiments, a region b2 with a decreasing number of stacks appears near the region b1 where the number of stacks is uniform.

[0517] In all these embodiments, the number of segments stacked in the uniform stacking area b1 is 10 or more. Preferably, the area with 10 or more segments stacked can be set as the ideal welding target area.

[0518] In these embodiments, the uniform stacking area b1 extends from the segment height variable area ( Figure 10a Starting from the radius point beginning with ②). In embodiments 2-1 to 2-5, the variable height zone of the segment ( Figure 10a (②) starts at 6 mm and extends outwards. In embodiments 3-1 to 3-4, the segment height variable zone ( Figure 10a (②) starts at 7 mm and extends outwards. In embodiments 4-3 to 4-4, the segment height variable zone ( Figure 10a (②) starts at 8 mm and extends outwards. In embodiments 5-1 to 5-2, the segment height variable zone ( Figure 10a ②) Starts from 9mm and extends outwards.

[0519] Table 5 below shows the results of calculating various parameters for embodiments 2-1 to 2-5, embodiments 3-1 to 3-4, embodiments 4-1 to 4-3, and embodiments 5-1 to 5-2. These parameters include the ratio (e / f) of the length of the uniform stacking area to the length from the radius point (6mm, 7mm, 8mm, 9mm) starting from the uniform stacking area to the outermost point (22mm) of the electrode assembly, the ratio (d / f) of the length of the segment height variable area (②) to the length from the radius point (6mm, 7mm, 8mm, 9mm) starting from the uniform stacking area to the outermost point (22mm) of the electrode assembly, etc.

[0520] [Table 5]

[0521]

[0522]

[0523] Referring to Implementation Methods 2-5, 3-4, 4-3, and 5-2 in Table 5, and... Figure 10a and Figure 10d The maximum height (h) of the segment in the segment's variable height region (②)N All are 10mm, but the minimum height of the segment (h1) increases to 4mm, 5mm, 6mm and 7mm in increments of 1mm, and the length of the height-variable zone (②) decreases to 6mm, 5mm, 4mm and 3mm in increments of 1mm. In the four embodiments, the ratio (e / f) of the uniform stacking area is the largest in embodiments 2-5, at 69%, and the smallest in embodiments 5-2, at 38%, and the number of stacks in the uniform stacking area is the same in all embodiments. According to the results shown in Table 5, when the maximum height of the segment (h1) is 10mm, the minimum height of the segment (h1) increases to 4mm, 5mm, 6mm and 7mm in increments of 1mm, and the length of the height-variable zone (②) decreases to 6mm, 5mm, 4mm and 3mm in increments of 1mm. N At the same time, it is understandable that, as the minimum height (h1) of the segment decreases, the width of the uniform stacking area increases proportionally with the increase of the width of the variable height area (②) of the segment. The reason is that the minimum height (h1) of the segment is smaller, and the radius point at the beginning of the segment is closer to the core, so the area of ​​segment stacking expands towards the core.

[0524] Referring to Table 5, it can be observed that the number of stacked segments ranges from 16 to 26, the ratio (d / f) of the segment height variable region (②) is 13% to 38%, and the ratio (e / f) of the stacking uniform region is 31% to 69%. Furthermore, the ratio (c / (ba)) of the segment skip region (①) to the radius (ba) of the electrode assembly (excluding the core) is 20% to 35%. Additionally, 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%.

[0525] In cylindrical batteries with form factors of 1865 and 2170, the radius of the electrode assembly is approximately 9 mm to 10 mm. Therefore, unlike the embodiments described, it is not possible to guarantee that the radial length of the segment region (f) is between 13 mm and 16 mm, and it is not possible to guarantee that the length of the segment skipping region (c, ①) is approximately 4 mm to 7 mm while simultaneously guaranteeing that the length of the uniformly stacked region (e) in which the number of segments is 10 or more is between 5 mm and 11 mm. This is because, in conventional cylindrical batteries, when the core radius is designed to be 2 mm (the same as in these embodiments), the radial region in which segments can be set is generally only 7 mm to 8 mm. Furthermore, in conventional cylindrical batteries, the length of the electrode in the winding direction is approximately 600 mm to 980 mm. This short length of the electrode is only about 15% to 24% of the electrode length in these embodiments (3948 mm for the positive electrode and 4045 mm for the negative electrode). Therefore, it is not easy to derive the numerical ranges of parameters h, i, and j from the design specifications of a conventional cylindrical battery.

[0526] Next, when the minimum height (h1) and maximum height (h) of the segment are... N When the height of the segments is the same in the variable region (②), the specific implementation will explain how the number of segments stacked varies in the radial direction of the bent surface region F according to the diameter of the core C of the electrode assembly.

[0527] The electrode assemblies in embodiments 6-1 to 6-6 have a radius of 22 mm, and the core C has a radius of 4 mm. In the height-variable region (②) of segment 61, the minimum height (h1) of the segment is 3 mm, and the maximum height (h2) of the segment is... N The height of the segment is changed from 5mm to 10mm in increments of 1mm. Therefore, in the electrode assemblies of embodiments 6-1 to 6-6, the width of the segment height variable area (②) is 2mm, 3mm, 4mm, 5mm, 6mm and 7mm respectively, and the segment skip area (①) is a radial area with a radius of 4mm to 7mm.

[0528] The electrode assemblies in embodiments 7-1 to 7-6 have a radius of 22 mm, and the core C has a radius of 2 mm. In the height-variable region (②) of segment 61, the minimum height (h1) of the segment is 3 mm, and the maximum height (h...) of the segment... N The segment height variable area (②) is changed from 5mm to 10mm in increments of 1mm. Therefore, in the electrode assemblies of embodiments 7-1 to 7-6, the width of the segment height variable area (②) is 2mm, 3mm, 4mm, 5mm, 6mm and 7mm respectively, and the segment skip area (①) is a radial area with a radius of 2mm to 5mm.

[0529] Figure 10e This is a graph showing the results of counting the number of segments stacked in the radial direction in the bent surface region F of the positive electrode formed at the upper portion of the electrode assembly according to embodiments 6-1 to 6-6 and embodiments 7-1 to 7-6. The same results are shown in the bent surface region of the negative electrode.

[0530] exist Figure 10e In the figure, graph (a) shows the result of counting the number of segments stacked in the radial direction in the bent surface area F of embodiments 6-1 to 6-6, and graph (b) shows the result of embodiments 7-1 to 7-6.

[0531] refer to Figure 10e In all embodiments, a uniform stacking region b1 is present. This uniform stacking region b1 is the radial region of the flat area in the graph. When the minimum height (h1) of the segments is the same, the length of the uniform stacking region b1 in the radial direction increases with the maximum height (h1) of the segments. N The number of segments increases as the maximum height (h) of the segment decreases. Meanwhile, in the uniform stacking region b1, the number of segments stacked increases with the maximum height (h) of the segment.N As the number of stacks increases, the number of stacks decreases. In these embodiments, a region b2 with a decreasing number of stacks is identified near the region b1 with a uniform number of stacks.

[0532] In all these embodiments, the number of segments stacked in the uniform stacking area b1 is 10 or more. Preferably, the area in which the number of segments stacked is 10 or more can be set as the ideal welding target area.

[0533] In these embodiments, the uniform stacking area b1 starts from a radius point that begins from the segment height variable area (②). In embodiments 6-1 to 6-6, the radius at the beginning of the segment height variable area (②) is 7 mm, and in embodiments 7-1 to 7-6, the radius at the beginning of the segment height variable area (②) is 5 mm.

[0534] Table 6 below shows the results of calculating various parameters for embodiments 6-1 to 6-6 and embodiments 7-1 to 7-6. These parameters include the ratio (e / f) of the length of the uniform stacking area to the length from the radius point (7mm, 5mm) starting from the uniform stacking area to the outermost point (22mm) of the electrode assembly, the ratio (d / f) of the length of the segment height variable area (②) to the length from the radius point (7mm, 5mm) starting from the uniform stacking area to the outermost point (22mm) of the electrode assembly, etc.

[0535] [Table 6]

[0536]

[0537]

[0538] See Figure 10a And in embodiments 6-6 and 7-6 of Table 6, the minimum height (h1) and maximum height (h2) of the segment in the segment height variable zone (②) NThe core radius is 3mm and 10mm respectively. However, in Embodiments 6-6, the core radius is 2mm larger than that in Embodiments 7-6. Therefore, in Embodiments 6-6, the uniform stacking area (e) and segment area (f) are 2mm smaller than those in Embodiments 7-6, and the number of segments stacked in the uniform stacking area is the same. These results are due to the difference in core radius. According to the results shown in Table 6, when the width of the segment height variable area (②) is the same, it can be understood that due to the smaller core radius (a), the ratio (d / f) of the height variable area (②) decreases, while the ratio (e / f) of the uniform stacking area increases. Referring to Table 6, it can be found that when the number of segments stacked is 13 to 26, the ratio (d / f) of the segment height variable area (②) is 12% to 47%, and the ratio (e / f) of the uniform stacking area is 40% to 76%. In addition, the ratio (c / (ba)) of the segment skipping area (①) to the radius (ba) of the electrode assembly excluding the core is 15% to 17%. In addition, the ratio of the length of the electrode region corresponding to the segment skipping zone (①) to the total length of the electrode is 6%, the ratio of the length of the electrode region corresponding to the height variable zone (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 zone (③) to the total length of the electrode is 59% to 83%.

[0539] For cylindrical batteries with form factors of 1865 and 2170, the radius of the electrode assembly is approximately 9 mm to 10 mm. Therefore, unlike the embodiments described, while ensuring the length of the segment skipping region (①) is around 3 mm, it is not possible to ensure the radial length of the segment region (f) is around 15 mm to 17 mm, nor is it possible to ensure the length of the uniform stacking region (e) with 10 or more segments is around 6 mm to 13 mm. This is because, in conventional cylindrical batteries, when the core radius is designed to be 2 mm (the same as in these embodiments), the radial region where segments can be set is generally only 5 mm to 8 mm. Furthermore, in conventional cylindrical batteries, the length of the electrode in the winding direction is approximately 600 mm to 980 mm. This short electrode length is only about 15% to 24% of the electrode length in these embodiments (3948 mm for the positive electrode and 4045 mm for the negative electrode). Therefore, it is not easy to derive the numerical ranges of parameters h, i, and j from the design specifications of conventional cylindrical batteries.

[0540] Taking into account the data in Tables 4 to 6, the number of segments stacked in the uniform segment stacking area can be 11 to 26. Furthermore, the ratio (d / f) of the segment height variable area (②) can be 6% to 47%. Furthermore, the ratio (e / f) of the uniform stacking area can be 31% to 82%. Furthermore, the ratio (c / (ba)) of the length of the segment skipping area (①) to the radius of the electrode assembly excluding the core can be 15% to 35%. Furthermore, the ratio of the length of the electrode area corresponding to the segment skipping area (①) to the total length of the electrode (length in the winding direction) can be 6% to 20%. Furthermore, the ratio of the length of the electrode area corresponding to the segment height variable area (②) to the total length of the electrode can be 3% to 32%. Furthermore, the ratio of the length of the electrode area corresponding to the segment height uniform area (③) to the total length of the electrode can be 59% to 87%.

[0541] Meanwhile, the parameters described in Tables 4 to 6 can be changed according to design factors, including: the radius of the core (a); the radius of the electrode assembly (b); and the minimum height (h1) and maximum height (h2) in the variable height zone (②) of the segment. N ;);The change in segment height (Δh) for every 1mm increase in radius; the thickness of the positive electrode, negative electrode, and diaphragm, etc.

[0542] Therefore, in the segment stacking uniformity zone, the segment stacking number can be increased to 10 to 35. The ratio (d / f) of the segment height variable zone (②) can be increased to 1% to 50%. Furthermore, the ratio (e / f) of the stacking uniformity zone can be increased to 30% to 85%. Furthermore, the ratio (c / (ba)) of the length of the segment skip zone (①) to the radius of the electrode assembly excluding the core can be increased to 10% to 40%. Furthermore, the ratio of the length of the electrode area corresponding to the segment skip zone (①) to the total length of the electrode (length in the winding direction) can be increased to 1% to 30%. Furthermore, the ratio of the length of the electrode area corresponding to the segment height variable zone (②) to the total length of the electrode can be increased to 1% to 40%. Furthermore, the ratio of the length of the electrode area corresponding to the segment height uniformity zone (③) to the total length of the electrode can be increased to 50% to 90%. In this embodiment, the maximum height (h) of the segments included in the height variable zone (②) and the height uniformity zone (③) is... N The height index N is 2 to 8. For example, referring to Table 4, the height indices N for embodiments 1-1 and 1-7 are 2 and 8, respectively. However, the height index N can be varied according to the amount of height change (Δh) of the segment in the radial direction of the electrode assembly. When the radial length of the height variable region (②) is fixed, if the amount of height change (Δh) of the segment decreases, the height index N increases accordingly, and vice versa. Preferably, the height index N can be further extended to 2 to 20, and optionally extended to 2 to 30.

[0543] In the bent surface region F formed at the upper and lower parts of the electrode assembly, the uniformly stacked region can be used as the welding target region for the current collector.

[0544] Preferably, the welding area of ​​the current collector overlaps with the uniformly stacked area of ​​the electrode assembly by at least 50% in the radial direction, and a higher overlap ratio is more preferred.

[0545] Preferably, the remaining area of ​​the welding zone of the current collector that does not overlap with the area with uniform stacking quantity can overlap with the area with decreasing stacking quantity that is adjacent to the area with uniform stacking quantity in the radial direction.

[0546] More preferably, the remaining area of ​​the welding zone of the current collector that does not overlap with the area with a uniform stacking number may overlap with the area with a stacking number of 10 or more in the area with a reduced stacking number.

[0547] It is ideal for welding current collectors to areas where the number of stacked segments is 10 or more, both in terms of weld strength and prevention of damage to the diaphragm or active material layer during welding. It is particularly useful when welding current collectors using high-power lasers with high penetration characteristics.

[0548] If a laser is used to weld a current collector and a uniformly stacked region containing 10 or more segments, even if the laser output is increased to improve the welding quality, the uniformly stacked region will absorb most of the laser energy to form weld beads. Therefore, the diaphragm and active material layer below the bent surface region F can be prevented from being damaged by the laser.

[0549] Furthermore, since the number of segments stacked is 10 or more in the laser-irradiated area, weld beads with sufficiently large volume and thickness are formed. Therefore, weld strength can be adequately guaranteed, and the resistance of the weld interface can be reduced to a level suitable for fast charging.

[0550] When welding the current collector, the laser output can be determined by the ideal weld strength between the bent surface region F and the current collector. The weld strength increases proportionally with the number of stacked segments. This is because as the number of stacks increases, the volume of the weld bead formed by the laser increases. Weld beads are formed when the materials of the current collector and the segments melt together. Therefore, when the weld bead volume is large, the connection between the current collector and the bent surface region is stronger and the contact resistance of the weld interface is reduced.

[0551] Preferably, the welding strength can be 2 kgf / cm. 2 Or greater, more preferably 4 kgf / cm 2 The maximum welding strength can be varied depending on the output of the laser welding equipment. Furthermore, the welding strength can preferably be set to 8 kgf / cm². 2Or smaller, preferably 6 kgf / cm 2 Or smaller. However, this disclosure is not limited thereto.

[0552] When the welding strength meets the above numerical range, even if strong vibrations are applied to the electrode assembly along the winding axis and / or radial direction, the properties of the welding interface will not deteriorate, and the resistance of the welding interface may be reduced due to the sufficiently large volume of the weld beads.

[0553] The laser power required to meet welding strength requirements varies depending on the laser equipment and can be appropriately adjusted within the range of 250W to 320W or 40% to 100% of the maximum laser output provided by the equipment.

[0554] Weld strength can be defined as the tensile force per unit area of ​​the current collector when it begins to separate from the bent surface region F (kgf / cm²). 2 Specifically, after the current collector is fully welded, a tensile force can be applied to it, gradually increasing the force. When the tensile force exceeds a threshold, the segment begins to separate from the weld interface. At this point, the value obtained by dividing the tensile force applied to the current collector by the area of ​​the current collector corresponds to the weld strength.

[0555] In the bent surface region F, segments are stacked into multiple layers, and according to the above embodiments, the number of stacked segments can be increased from a minimum of 10 to a maximum of 35.

[0556] The thickness of the positive current collector (foil) constituting the uncoated portion 43 is 10 μm to 25 μm, and the thickness of the negative current collector (foil) constituting the uncoated portion 43 is 5 μm to 20 μm. Therefore, the bending surface region F of the positive electrode may include a region in which the total stack thickness of the segments is 100 μm to 875 μm. Furthermore, the bending surface region F of the negative electrode may include a region in which the total stack thickness of the segments is 50 μm to 700 μm.

[0557] Figure 10f This is a top plan view showing an electrode assembly according to one embodiment of the present disclosure, showing a uniform stacking area b1 and a reduced stacking area b2 in the bending surface region F of segments 61, 61'.

[0558] refer to Figure 10f The area between the two circles indicated by the thick solid line corresponds to the bending surface area F of the segment, and the area between the two circles indicated by the dotted line corresponds to the stacking quantity uniform area b1, in which the number of segments stacked is 10 or more, and the outer area of ​​the stacking quantity uniform area b1 corresponds to the stacking quantity decreasing area b2.

[0559] In one embodiment, when the current collector (P) cWhen welding to the bent surface area F, in the current collector (P) c Welding patterns (W) are generated on the surface of the surface. p Welding pattern (W) p It can be an array of line or dot patterns. Welding patterns (W) p This corresponds to the welding zone and can overlap with the uniformly stacked segment area b1 in the radial direction by 50% or more. Therefore, a portion of the welding pattern (W) p ) can be included in the uniform stacking area b1, and the remaining portion of the welding pattern (W) p This can be included in the stacking reduction region b2, outside the uniform stacking region b1. Of course, the entire welding pattern (W) p It can overlap with the uniform stacking area b1 to maximize the welding strength and reduce the resistance of the welding area.

[0560] The area of ​​the bending surface region F can be defined as the sum of the area of ​​the uniform stacking region b1 and the area of ​​the decreasing stacking region b2. Since the ratio (e / f) of the uniform stacking region b1 is 30% to 85%, preferably 31% to 82%, the ratio of the area of ​​the uniform stacking region b1 to the area of ​​the bending surface region F can be 9% (30%). 2 / 100 2 ) to 72% (85) 2 / 100 2 ), preferably 10% (31) 2 / 100 2 ) to 67% (82) 2 / 100 2 ).

[0561] Preferably, the current collector (P) c The edge of the portion of the contact bending surface area F can cover the ends of the segments 61, 61' that bend towards the core C in the last winding of the height uniform area (③). In this case, due to the welding pattern (W p ) Formed in segments 61 and 61' by the current collector (P) c Under the pressed state, therefore the current collector (P) c The segments 61 and 61' are firmly connected to the bent surface area F. Therefore, since the segments 61 and 61' stacked along the winding axis are in close contact with each other, the resistance at the welding interface can be reduced and the segments 61 and 61' can be prevented from lifting.

[0562] Meanwhile, the bending direction of the segment can be opposite to that described above. That is, the segment can be bent from the core toward the outer periphery. In this case, the pattern in which the height of the segment varies along the winding direction (X-axis direction) can be opposite to the pattern in the above-described embodiment (variant). For example, the height of the segment can gradually decrease from the core toward the outer periphery. Furthermore, the structure applied to the first part B1 and the structure applied to the second part B3 can be interchanged. Preferably, the height variation pattern can be designed such that the height of the segment gradually decreases from the core toward the outer periphery, but when the segment closest to the outer periphery of the electrode assembly is bent toward the outer periphery, the end of the segment is not exposed outside the outer periphery of the electrode assembly.

[0563] The electrode structures described above (variants) can be applied to at least one of a first electrode and a second electrode with different polarities, included in a core-type electrode assembly or another type of electrode assembly known in the art. Furthermore, when the electrode structure described above (variants) is applied to either the first electrode or the second electrode, a conventional electrode structure can be applied to the other. Additionally, the electrode structures applied to the first electrode and the second electrode may not be identical but different from each other.

[0564] For example, when the first electrode and the second electrode are positive and negative electrodes respectively, any of the above embodiments (variations) can be applied to the first electrode, and a conventional electrode structure can be applied to the second electrode (see Figure 1 ).

[0565] As another embodiment, when the first electrode and the second electrode are positive and negative electrodes respectively, any of the above embodiments (variations) can be selectively applied to the first electrode, and any of the above embodiments (variations) can be selectively applied to the second electrode.

[0566] In this disclosure, the positive electrode active material coated on the positive electrode and the negative electrode active material coated on the negative electrode can be any active material known in the art without limitation.

[0567] In one embodiment, the positive electrode active material may include materials of the general formula A[A x M y ]O 2+z The alkali metal compound represented (A includes at least one of Li, Na, and K; M includes at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Mo, Sc, Zr, Ru, and Cr; x ≥ 0, 1 ≤ x + y ≤ 2, -0.1 ≤ z ≤ 2; and the stoichiometric coefficients of x, y, and z are chosen to maintain the electroneutrality of the compound).

[0568] In another embodiment, the positive electrode active material may be an alkali metal compound xLiM1O2(1-x)Li2M2O3 disclosed in US 6,677,082, US 6,680,143, etc. (M1 includes at least one element with an average oxidation state of 3; M2 includes at least one element with an average oxidation state of 4; and 0≤x≤1).

[0569] In yet another embodiment, the positive electrode active material can be made of Li... a M1 x Fe 1-x M2 y P 1-y M3 z O 4-z (M1 includes at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Mg, and Al; M2 includes at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Mg, Al, As, Sb, Si, Ge, V, and S; M3 includes a halogen element that optionally includes F; 0 < a ≤ 2, 0 ≤ x ≤ 1, 0 ≤ y < 1, 0 ≤ z < 1; the stoichiometric coefficients of a, x, y, and z are selected to maintain the electroneutrality of the compound) or Li3M2(PO4)3 (M includes at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Mg, and Al) represents a lithium metal phosphate.

[0570] In another embodiment, as a major component, the positive electrode active material may include a lithium intercalating material selected from: layered compounds, such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2) or compounds substituted with one or more transition metals; lithium manganese oxide (LiMnO2), such as Li 1+x Mn 2-x O4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, and LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides, such as LiV3O8, LiFe3O4, V2O5, and Cu2V2O7; and LiNi1M x Lithium-nickel composite oxides represented by O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); and those represented by the formula LiMn 2-x M x O2 (where M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or Li2Mn 3mLithium-manganese composite oxides represented by O8 (where M = Fe, Co, Ni, Cu or Zn); LiMn2O4, wherein a portion of the lithium is replaced by alkaline earth metal ions; disulfide compounds; Fe2(MoO4)3, or composite oxides formed by combinations thereof.

[0571] The positive electrode current collector has a thickness ranging from, for example, 3 μm to 500 μm. The positive electrode current collector is not particularly limited, as long as it is conductive without causing chemical changes in the battery, and can be made of materials such as stainless steel, aluminum, nickel, titanium, sintered carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. The positive electrode current collector can have fine irregularities formed on its surface to increase the adhesion strength of the positive electrode active material, and can take various forms such as films, sheets, foils, meshes, porous materials, foams, and nonwoven fabrics.

[0572] The conductive material can be additionally mixed with the positive electrode active material particles. For example, the amount of conductive material added is from 1% to 50% (by weight) of the total weight of the mixture including the positive electrode active material. The conductive material is not particularly limited, as long as it has high conductivity without causing chemical changes in the battery, and can be, for example, selected from the following conductive materials: graphite, such as natural graphite and artificial graphite; carbon black, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; conductive fibers, such as carbon fibers and metal fibers; metal powders, such as fluorinated carbon, aluminum, and nickel powders; conductive whiskers, such as zinc oxide and potassium titanate; conductive oxides, such as titanium oxide; polyphenylene derivatives, etc.

[0573] Preferably, the positive electrode active material may include primary particles and / or secondary particles aggregated from primary particles.

[0574] In addition, the negative electrode is manufactured by applying negative electrode active material particles onto the negative electrode current collector and drying them, and may also include the aforementioned conductive materials, binders and solvents if desired.

[0575] The negative electrode current collector has a thickness ranging from, for example, 3 μm to 500 μm. There are no particular limitations on the negative electrode current collector, as long as it is conductive and does not cause chemical changes in the battery. Materials used include, for example, copper, stainless steel, aluminum, nickel, titanium, sintered carbon, aluminum-cadmium alloys, and copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. Furthermore, similar to the positive electrode current collector, the bonding force of the negative electrode active material can be strengthened by forming fine irregularities on the surface, and the negative electrode current collector can be used in various forms (such as films, sheets, foils, meshes, porous bodies, foams, and nonwoven fabrics).

[0576] In one embodiment, the negative electrode active material may be a carbon material, a lithium metal or a lithium metal compound, a silicon or a silicon compound, a tin or a tin compound, etc. Metal oxides having a potential less than 2V (such as TiO2 and SnO2) may also be used as the negative electrode active material. As the carbon material, low-crystalline carbon and high-crystalline carbon, etc. may be used.

[0577] In another embodiment, the negative electrode active material may use, for example, carbon, such as non-graphitizable carbon, graphitizable carbon, etc.; Li x Fe2O3(where 0 ≤ x ≤ 1), Li x WO2(where 0 ≤ x ≤ 1), Sn x Me1Me’yO z (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, elements of the first, second and third groups of the periodic table, halogens; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8) metal composite oxides; lithium alloys; silicon-based alloys; tin-based alloys; oxides, such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4 and Bi2O5; conductive polymers, such as polyacetylene; Li-Co-Ni substrates, etc.

[0578] The binder polymer that can be used for the electrode is a component that helps the connection of the electrode active material particles with the conductive material, etc. and the connection with the electrode current collector, and for example, its addition amount is 1 wt% to 50 wt% based on the total weight of the mixture containing the electrode active material. For example, the binder polymer may use any binder polymer selected from the group consisting of: polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF); polyvinylidene fluoride-trichloroethylene copolymer; polymethyl methacrylate; polybutyl acrylate; polyacrylonitrile; polyvinyl pyrrolidone; polyvinyl acetate; ethylene-vinyl acetate copolymer; poly(ethylene oxide); polyarylate; cellulose acetate; cellulose acetate butyrate; cellulose acetate propionate; cyanoethylated amylose; cyanoethylated polyvinyl alcohol; cyanoethylated cellulose; cyanoethylated sucrose; amylose; and carboxymethyl cellulose; or a mixture thereof, but not limited thereto.

[0579] Non-limiting examples of the solvent for preparing the electrode include acetone, tetrahydrofuran, dichloromethane, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, water or a mixture thereof. These solvents provide an appropriate viscosity level so that a slurry coating layer can be formed on the surface of the electrode current collector at an ideal level.

[0580] The negative electrode includes: a current collector; and a negative electrode active material layer, which is located on at least one surface of the current collector and includes a negative electrode active material, a binder polymer, and a conductive material. The negative electrode active material layer includes a lower region in contact with the surface of the current collector and an upper region in contact with the surface of the lower region and extending to the surface of the negative electrode active material layer. Furthermore, the lower region and the upper region may independently include at least one of graphite and a silicon-based compound as the negative electrode active material.

[0581] The lower region may include natural graphite as the negative electrode active material, and the upper region may include artificial graphite as the negative electrode active material.

[0582] The lower and upper regions can each independently include silicon-based compounds as negative electrode active materials.

[0583] Silicon-based compounds may include SiO x (0≤x≤2) and at least one of SiC.

[0584] According to one embodiment of the present invention, a negative electrode can be manufactured by applying a lower slurry containing a lower negative electrode active material to a current collector and drying it to form a lower region, and then applying an upper slurry containing an upper negative electrode active material to the lower region and drying it to form an upper region.

[0585] Furthermore, according to one embodiment of this disclosure, the negative electrode can be manufactured by the following steps: preparing a lower slurry containing a lower negative electrode active material; and an upper slurry containing an upper negative electrode active material;

[0586] The lower slurry is coated onto one surface of the negative electrode current collector, while the upper slurry is coated onto the lower slurry simultaneously or at a predetermined time difference; and

[0587] An active material layer is formed by simultaneously drying the lower and upper slurries.

[0588] When the negative electrode is manufactured using the latter method, a mixed region containing these different types of active materials can exist in the portion where the lower and upper regions of the negative electrode come into contact with each other. This is because when the active material layer is formed by simultaneously or sequentially coating a lower slurry, provided as the lower negative electrode active material, and an upper slurry, provided as the upper negative electrode active material, onto a current collector with a very short time difference and then drying them simultaneously, a predetermined mixed region is generated at the interface where the lower and upper slurries come into contact before drying, and then during drying, this mixed region is formed in the form of a layer of mixed regions.

[0589] In the active material layer of the negative electrode according to one embodiment of the present disclosure, the weight ratio (or the ratio of the loading per unit area) of the upper layer region to the lower layer region can be from 20:80 to 50:50, specifically from 25:75 to 50:50.

[0590] The thicknesses of the lower and upper regions of the negative electrode active material layer of this disclosure do not perfectly match the thicknesses of the coated lower and upper slurries. However, as a result of a drying or selective rolling process, the ratio of the thicknesses of the lower and upper regions of the negative electrode active material layer of this disclosure can eventually match the ratio of the thicknesses of the coated lower and upper slurries.

[0591] A first slurry is applied, and a second slurry is applied simultaneously or at a predetermined time difference onto the first slurry. According to one embodiment of this disclosure, the predetermined time difference may be 0.6 seconds or less, or 0.02 seconds to 0.6 seconds, or 0.02 seconds to 0.06 seconds, or 0.02 seconds to 0.03 seconds. Since the time difference arises during the application of the first and second slurries due to the coating equipment, simultaneous application of the first and second slurries may be more preferable. A device such as a double-slot mold can be used to apply the second slurry onto the first slurry.

[0592] The step of forming the active material layer may also include rolling the active material layer after the drying step. In this case, rolling can be performed using methods commonly used in the art, such as roll forming, and can be carried out at a pressure of 1 MPa to 20 MPa and a temperature of 15°C to 30°C.

[0593] The process of simultaneously drying the coated lower slurry and the coated upper slurry to form an active material layer can be carried out using a device that combines a hot air drying device and an infrared drying device, which is commonly used in the art.

[0594] The weight percentage of the first binder polymer in the solids content of the lower slurry can be equal to or greater than the weight percentage of the second binder polymer in the solids content of the upper slurry. According to one embodiment of this disclosure, the weight percentage of the first binder polymer in the solids content of the lower slurry can be 1.0 to 4.2 times, 1.5 to 3.6 times, or 1.5 to 3 times the weight percentage of the second binder polymer in the solids content of the upper slurry.

[0595] When the weight percentage of the first binder in the coated lower slurry and the weight percentage of the second binder in the coated upper slurry meet the above range, the binder in the lower region will not be too little, thus preventing electrode layer separation. Furthermore, since there is not too much binder in the upper region, the resistance of the upper electrode layer is reduced, and fast charging performance may be advantageous.

[0596] In the solids content of the lower layer slurry, the weight percentage of the first binder polymer can be 2% to 30% by weight, or 5% to 20% by weight, and the proportion (by weight) of the second binder polymer in the solids content of the upper layer slurry can be 0.5% to 20% by weight, or 1% to 15% by weight, or 1% to 10% by weight, or 2% to 5% by weight.

[0597] The total ratio (by weight) of the first binder polymer and the second binder polymer in the total solids content of the lower and upper slurries can be from 2% to 20% by weight, or from 5% to 15% by weight.

[0598] The membrane comprises: a porous polymer substrate; and a porous coating layer located on both surfaces of the porous polymer substrate and containing inorganic particles and a binder polymer.

[0599] Porous polymer substrates can be porous substrates based on polyolefins.

[0600] The porous polyolefin substrate can be in the form of a membrane or a nonwoven mesh. Due to the porous structure described above, the electrolyte can move smoothly between the positive and negative electrodes, and the substrate's own electrolyte impregnation properties are improved, thus ensuring excellent ionic conductivity. Furthermore, it prevents an increase in internal resistance of the electrochemical device, thereby preventing a deterioration in the device's performance.

[0601] As the polyolefin porous substrate used in this disclosure, any planar porous substrate commonly used in electrochemical devices can be used, and its material or shape can be selected in various ways depending on the purpose.

[0602] The polyolefin porous substrate can be a film or nonwoven web formed of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene or mixtures thereof, but is not limited thereto.

[0603] Polyolefin porous substrates can have a thickness of 8 μm to 30 μm, but this is just an example, and thicknesses exceeding this range can be used to take into account the mechanical properties of the battery or the high-rate charge / discharge characteristics.

[0604] The nonwoven sheet according to this disclosure can be formed from polyethylene (PE), polypropylene (PP), or mixtures thereof. For example, the nonwoven sheet can be manufactured by fiber spinning. For example, the nonwoven sheet can be manufactured by forming fibers of the above materials into fiber-spun forms at their melting point or higher and then spinning them together using a melt-blowing method.

[0605] The nonwoven sheet may have an elongation of 200% to 400%, more preferably 300% to 400%. If the elongation is less than 200%, the probability of contact between electrodes increases when pins are inserted, and if the elongation is greater than 400%, the area around the pins also elongates, causing the separator membrane to become thinner and reducing barrier performance.

[0606] Multiple pores with an average diameter of 0.1 μm to 10 μm are formed in the nonwoven sheet. If the pore size is less than 0.1 μm, smooth movement of lithium ions and / or electrolyte may not be possible, and if the pore size is greater than 10 μm, the effect of this disclosure—preventing contact between the positive and negative electrodes by elongating the nonwoven sheet during pin insertion—may not be achieved.

[0607] Furthermore, the nonwoven sheet can have a porosity of 40% to 70%. If the porosity is less than 40%, smooth movement of lithium ions and / or electrolytes may not be possible, and if the porosity is greater than 70%, the effect of this disclosure—preventing contact between the positive and negative electrodes by elongating the nonwoven sheet during pinning—may not be achieved. The nonwoven sheet prepared in this manner has an air permeability of 1 to 20 seconds / 100 mL.

[0608] Furthermore, the thickness of the nonwoven sheet can be from 10 μm to 20 μm, but this is only an example and the disclosure is not limited thereto. Depending on the permeability of the nonwoven sheet, a nonwoven sheet with a thickness exceeding this range can be used.

[0609] The nonwoven sheet can be laminated to a diaphragm located beneath the nonwoven sheet. Lamination can be performed in a temperature range of 100°C to 150°C. When lamination is performed at temperatures below 100°C, no lamination effect occurs, and when lamination is performed at temperatures above 150°C, part of the nonwoven fabric melts.

[0610] Compared to diaphragms made from conventional nonwoven sheets, diaphragms laminated under the above conditions according to embodiments of the present disclosure have improved nail penetration resistance compared to diaphragms in which a layer containing inorganic particles is formed on at least one surface of the membrane or nonwoven sheet.

[0611] In a porous coating, inorganic particles can be bonded together by a binder polymer while charged and in contact with each other, thus forming interstitial volumes between the inorganic particles. These interstitial volumes can then become empty spaces to form pores.

[0612] When inorganic particles are used to form a porous coating, further inorganic particles can be added, i.e., within the operating voltage range of the electrochemical device (e.g., based on Li / Li). +Inorganic particles (0V to 5V) that do not undergo oxidation and / or reduction reactions. In particular, when using inorganic particles with ion transfer capabilities, performance can be improved by increasing the ionic conductivity in the electrochemical device. Furthermore, when using inorganic particles with high dielectric constants as inorganic particles, the ionic conductivity of the electrolyte can be improved by contributing to increasing the degree of dissociation of electrolyte salts (e.g., lithium salts) in the liquid electrolyte.

[0613] For the reasons stated above, inorganic particles preferably include high dielectric constant inorganic particles having a dielectric constant of 5 or greater, preferably 10 or greater, inorganic particles having lithium-ion transfer capability, or mixtures thereof.

[0614] Non-limiting embodiments of inorganic particles with a dielectric constant of 5 or greater include BaTiO3, Pb(Zr,Ti)O3(PZT), and Pb 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg) 1 / 3 Nb 2 / 3 Hafnium dioxide (HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiC or mixtures thereof.

[0615] In particular, the aforementioned inorganic particles (such as BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg) 1 / 3 Nb 2 / 3 O3-PbTiO3 (PMN-PT) and hafnium dioxide (HfO2) not only exhibit high dielectric constants of 100 or greater, but also possess piezoelectric properties, generating a potential difference between particle surfaces by applying pressure to stretch or compress the inorganic particles. Therefore, internal short circuits between electrodes due to external impacts can be prevented, thereby improving the safety of electrochemical devices. Furthermore, when these high-dielectric-constant inorganic particles are mixed with inorganic particles capable of lithium-ion transfer, their synergistic effect can be enhanced.

[0616] Inorganic particles with lithium ion transfer ability refer to inorganic particles containing lithium element and having the function of moving lithium ions without storing lithium. Since the inorganic particles with lithium ion transfer ability transfer and move lithium ions due to the defects existing inside the particle structure, the lithium ion conductivity in the battery is improved, thereby improving the battery performance. Non-limiting examples of inorganic particles with lithium ion transfer ability include: lithium phosphate (Li3PO4); lithium titanium phosphate (Li x Ti y (PO4)3, 0 < x < 2, 0 < y < 3); lithium aluminum titanium phosphate (Li x Al y Ti z (PO4)3, 0 < x < 2, 0 < y < 1, 0 < z < 3); (Li Al Ti P) x O y series glasses (0 < x < 4, 0 < y < 13), such as 14Li2O2O3-38TiO2-39P2O5; lithium lanthanum titanate (Li x La y TiO3, 0 < x < 2, 0 < y < 3); lithium germanium thiophosphate (Li x Ge y P z S w , 0 < x < ④, 0 < y < 1, 0 < z < 1, 0 < w < 5), such as Li 3.25 Ge 0.25 P 0.75 S4; lithium nitride (Li x N y , 0 < x < 4, 0 < y < 2), such as Li3N; SiS2 series glasses (Li x Si y S z , 0 < x < 3, 0 < y < 2, 0 < z < 4), such as Li3PO4-Li2S-SiS2; P2S5 series glasses (Li x P y S z , 0 < x < 3, 0 < y < 3, 0 < z < 7), such as LiI-Li2S-P2S5; or mixtures thereof.

[0617] The size of the inorganic particles in the porous coating layer is not limited, but is preferably 0.001 μm to 10 μm to form a coating layer with uniform thickness and appropriate porosity. If the size is less than 0.001 μm, the dispersibility of the inorganic particles may deteriorate. If the size exceeds 10 μm, the thickness of the porous coating layer may increase, resulting in poor mechanical properties. Due to the too large pore size, the probability of internal short circuit during the charge and discharge process of the battery increases.

[0618] The adhesive polymer forming the porous coating can be any adhesive polymer selected from, but not limited to, the group consisting of, polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF), polyvinylidene fluoride-trichloroethylene copolymer, polymethyl methacrylate, polybutyl acrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylates, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl amylopectin, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, amylopectin, and carboxymethyl cellulose, or mixtures thereof.

[0619] The composition ratio of inorganic particles to binder polymer used in the porous coating is preferably in the range of, for example, 50:50 to 99:1, more preferably 70:30 to 95:1. If the content ratio of inorganic particles to binder polymer is less than 50:50, the content of binder polymer increases, and the improvement in the thermal safety of the separator may deteriorate. Furthermore, the reduction in the empty spaces formed between inorganic particles may decrease pore size and porosity, ultimately leading to a deterioration in battery performance. If the content of inorganic particles exceeds 99 parts by weight, the peel resistance of the porous coating may be weakened due to the insufficient content of binder polymer. The thickness of the porous coating is not particularly limited, but is preferably in the range of 0.01 μm to 20 μm. Furthermore, the pore size and porosity are not particularly limited, but the pore size is preferably in the range of 0.001 μm to 10 μm, and the porosity is preferably in the range of 10% to 90%. The pore size and porosity depend primarily on the size of the inorganic particles. For example, when inorganic particles with a particle size of 1 μm or smaller are used, pores are also formed with a size of about 1 μm or smaller. This pore structure is filled with an electrolyte that is subsequently injected, and the electrolyte acts as a transfer ion. When the pore size and porosity are less than 0.001 μm and 10%, respectively, the pores may act as a resistive layer, and when the pore size and porosity exceed 10 μm and 90%, respectively, the mechanical properties may deteriorate.

[0620] A porous coating can be formed by dissolving or dispersing a binder polymer in a dispersion medium, adding inorganic particles to obtain a slurry for forming the porous coating, applying the slurry to at least one surface of a substrate, and drying the slurry. The dispersion medium preferably has a solubility index similar to that of the binder polymer used and a low boiling point. This is to facilitate uniform mixing and subsequent removal of the dispersion medium. Non-limiting examples of available dispersion media include acetone, tetrahydrofuran, dichloromethane, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, water, or mixtures thereof.

[0621] Preferably, the inorganic particles are crushed after being added to the dispersion in which the binder polymer is dispersed in the dispersion medium. In this case, a suitable crushing time is 1 to 20 hours, and the particle size of the crushed inorganic particles is preferably 0.001 μm to 10 μm, as described above. Conventional methods can be used as crushing methods, and ball milling is particularly preferred.

[0622] Subsequently, the binder polymer dispersion containing inorganic particles is coated onto at least one surface of a porous polymer substrate under humidity conditions of 10% to 80% and then dried. Conventional coating methods known in the art, such as dip coating, die coating, roll coating, comma coating, or a combination thereof, can be used as a method for coating the dispersion onto the porous polymer substrate.

[0623] In addition to the inorganic particles and binder polymers mentioned above that serve as components of the porous coating layer, other additives, such as conductive agents, may also be included.

[0624] The separator manufactured according to this disclosure can have a thickness of 1 μm to 100 μm or 5 μm to 50 μm. If the thickness is less than 1 μm, the function of the separator may not be fully realized and the mechanical properties may deteriorate. If the thickness exceeds 100 μm, the characteristics of the battery may deteriorate during high-rate charge and discharge. Furthermore, the separator can have a porosity of 40% to 60% and a permeability of 150 to 300 seconds / 100 mL.

[0625] According to one embodiment of this disclosure, the porous polymer substrate can be polyethylene or polypropylene. Furthermore, alumina and silica substrates can be used as inorganic particles in the porous coating layer.

[0626] When using the diaphragm according to one embodiment of this disclosure, since both surfaces of the porous polymer substrate are provided with porous coatings, a uniform solid electrolyte interface layer can be formed by improving the impregnation performance of the electrolyte, and superior air permeability can be ensured compared to diaphragms with a single-sided inorganic coating. For example, the air permeability can be less than 120 s / 100 cc. Furthermore, even if the inorganic porous coating is provided on both surfaces, a thickness comparable to that of a conventional single-sided inorganic coated diaphragm can be achieved. For example, the thickness can be less than 15.0 μm.

[0627] Furthermore, when using the separator according to one embodiment of this disclosure, the stability of the separator is improved to ensure heat resistance and pressure resistance. Specifically, heat resistance with a thermal shrinkage characteristic of less than 5% at 180°C can be guaranteed, and puncture strength characteristics of 550 gf or greater can be guaranteed. Moreover, when core deformation occurs during the cycling of a battery using this separator, damage or penetration of the separator at the stepped portion of the core can be prevented.

[0628] The diaphragm can be a porous polymer membrane, such as a porous polymer membrane made of polyolefin-based polymers (such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, etc.) or their laminates. As another embodiment, the diaphragm can be made of a common porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc.

[0629] The structure of an electrode assembly according to one embodiment of the present disclosure will be described in detail below.

[0630] Figure 11 This is a cross-sectional view of the wound core type electrode assembly 80 cut along the Y-axis direction (winding axis direction), in which the first electrode (positive electrode) and the second electrode (negative electrode) are electrodes 40 according to the first embodiment.

[0631] You can refer to Figure 2 The described winding method manufactures the electrode assembly 80. For ease of description, the protruding structures of the first uncoated portion 43a and the second uncoated portion 43b extending to the outside of the diaphragm are shown in detail, and the winding structure of the first electrode, the second electrode, and the diaphragm is not shown. The upwardly protruding first uncoated portion 43a extends from the first electrode, and the downwardly protruding second uncoated portion 43b extends from the second electrode.

[0632] A schematic diagram illustrates the height variation of the first uncoated portion 43a and the second uncoated portion 43b. That is, the height of the uncoated portion can vary irregularly depending on the position of the cut profile. For example, if the trapezoidal segments 61, 61' or the side of the cut groove 63 are cut, the height of the uncoated portion in the profile is lower than the height (H) of segments 61, 61'. Therefore, it should be understood that the height of the uncoated portion shown in the cross-sectional view of the electrode assembly corresponds to the height of the uncoated portion included in each winding turn. Figure 7b and Figure 8b The average value of H in the data.

[0633] refer to Figure 11 The first uncoated portion 43a includes a first portion B1 adjacent to the core of the electrode assembly 80, a second portion B3 adjacent to the outer peripheral surface of the electrode assembly 80, and a third portion B2 inserted between the first portion B1 and the second portion B3.

[0634] The height (length in the Y-axis direction) of the second part B3 is relatively smaller than the height of the third part B2. Therefore, it is possible to prevent internal short circuits that could occur when the rolled edge of the battery casing is pressed near the second part B3 and the second part B3 come into contact with each other.

[0635] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a variant, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure as in other embodiments (variants).

[0636] The ends 81 of the first uncoated portion 43a and the second uncoated portion 43b can be bent in the radial direction of the electrode assembly 80, for example, bent from the outer periphery toward the core. In this case, the second portion B3 can remain largely unbent.

[0637] Figure 12 This is a cross-sectional view of the core-type electrode assembly 90 cut along the Y-axis direction (winding axis direction). In this core-type electrode assembly, the first electrode (positive electrode) and the second electrode (negative electrode) are electrode 45 of the second embodiment.

[0638] refer to Figure 12 The first uncoated portion 43a of the first electrode includes a first portion B1 adjacent to the core of the electrode assembly 90, a second portion B3 adjacent to the outer peripheral surface of the electrode assembly 90, and a third portion B2 inserted between the first portion B1 and the second portion B3.

[0639] The height of the second part B3 is relatively smaller than that of the third part B2, and it gradually decreases from the core towards the outer periphery. Therefore, it can prevent internal short circuits from occurring when the rolled edge of the battery casing comes into contact with the second part B3 when it is pressed near the second part B3.

[0640] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a variant, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (variants).

[0641] The ends 91 of the first uncoated portion 43a and the second uncoated portion 43b can be bent in the radial direction of the electrode assembly 90, for example, bent from the outer periphery toward the core. In this case, the outermost 92 of the second portion B3 can remain largely unbent.

[0642] Figure 13 This is a cross-sectional view of the core-type electrode assembly 100 cut along the Y-axis direction (winding axis direction). In this core-type electrode assembly, the first electrode (positive electrode) and the second electrode (negative electrode) are electrodes 50, 60, and 70 of the third to fifth embodiments (variations thereof).

[0643] refer to Figure 13 The first uncoated portion 43a of the first electrode includes a first portion B1 adjacent to the core of the electrode assembly 100, a second portion B3 adjacent to the outer peripheral surface of the electrode assembly 100, and a third portion B2 inserted between the first portion B1 and the second portion B3.

[0644] The height of the first part B1 is relatively smaller than the height of the third part B2. Furthermore, in the third part B2, the bending length of the innermost uncoated portion 43a is equal to or less than the radial length (R) of the first part B1. The bending length (H) corresponds to the distance from the bending point of the uncoated portion 43a to its top. In a variant, the bending length H may be less than the sum of the radial length (R) of the first part B1 and 10% of the radius of the core 102.

[0645] Therefore, even if the third part B2 is bent, more than 90% of the diameter of the core 102 of the electrode assembly 100 is still open to the outside. The core 102 is a cavity at the center of the electrode assembly 100. If the core 102 is not obstructed, the electrolyte injection process is not difficult, and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the core 102, the welding process between the current collector of the negative (or positive) electrode and the battery casing (or terminal) can be easily performed.

[0646] The height of the second part B3 is relatively smaller than the height of the third part B2. Therefore, when the rolled edge of the battery casing is pressed near the second part B3, it can prevent an internal short circuit from occurring when the rolled edge and the second part B3 come into contact with each other.

[0647] In a variant example, with Figure 13 As shown, the height of the second part B3 can decrease gradually or incrementally. Furthermore, in... Figure 13 In the middle, although the height of the third part B2 is the same in the vicinity of the outer periphery, the height of the third part B2 can gradually or progressively increase from the boundary between the first part B1 and the third part B2 toward the boundary between the third part B2 and the second part B3. When the third part B2 is divided into multiple segments, the area where the height of the uncoated part 43a varies corresponds to the segment height variable area ( Figure 10a (② in the middle).

[0648] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a variant, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (variants).

[0649] The ends 101 of the first uncoated portion 43a and the second uncoated portion 43b can be bent in the radial direction of the electrode assembly 100, for example, bent from the outer periphery toward the core. In this case, the first portion B1 and the second portion B3 are not bent substantially.

[0650] When the third part B2 comprises multiple segments, bending stress can be relieved to prevent the uncoated portion 43a near the bending point from being torn or abnormally deformed. Furthermore, when the width and / or height and / or separation distance of the segments are adjusted according to the numerical ranges of the above embodiments, the segments bend towards the core and overlap in several layers to sufficiently ensure adequate weld strength, and no empty holes (gap) are formed in the bending surface area.

[0651] Figure 14 A cross-sectional view of the electrode assembly 110 according to another embodiment of the present disclosure, cut along the Y-axis direction (winding axis direction).

[0652] refer to Figure 14 Except that the height of the second part B3 is roughly the same as the outermost height of the third part B2, the configuration of the electrode assembly 110 is similar to... Figure 13 The configuration of the electrode assembly 100 is largely the same.

[0653] Part B3 may include multiple segments. The arrangement of the multiple segments is generally the same as that in the fourth and fifth embodiments (variants) of the electrodes.

[0654] In the electrode assembly 110, the height of the first portion B1 is relatively smaller than the height of the third portion B2. Furthermore, in the third portion B2, the bending length (H) of the innermost uncoated portion is equal to or less than the radial length (R) of the first portion B1. Preferably, the first portion B1 can be a segment skip region without segments. Figure 10a (① in the example). In a variant, the bending length H may be less than the sum of the radial length (R) of the first part B1 and 10% of the radius of the core 112.

[0655] Therefore, even if the third part B2 is bent, the core 112 of the electrode assembly 110 remains open to the outside, with more than 90% of its diameter exposed. If the core 112 is not obstructed, there are no difficulties during electrolyte injection, and the electrolyte injection efficiency is improved. Furthermore, by inserting a welding jig through the core 112, the welding process between the current collector of the negative (or positive) electrode and the battery casing (or terminals) can be easily performed.

[0656] In one variant, the structure in which the height of the third portion B2 gradually or progressively increases from the core toward the outer periphery can extend to the second portion B3. In this case, the height of the uncoated portion 43a can gradually or progressively increase from the boundary between the first portion B1 and the third portion B2 toward the outermost surface of the electrode assembly 110.

[0657] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a variant, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (variants).

[0658] The ends 111 of the first uncoated portion 43a and the second uncoated portion 43b can be bent in the radial direction of the electrode assembly 110, for example, bent from the outer periphery toward the core. In this case, the first portion B1 is substantially not bent.

[0659] When the third part B2 and the second part B3 include multiple segments, bending stress is relieved, thereby preventing tearing or abnormal deformation of the uncoated portions 43a and 43b near the bending point. Furthermore, when the width and / or height and / or separation distance of the segments are adjusted according to the numerical ranges of the above embodiments, the segments bend towards the core and overlap in several layers to sufficiently ensure adequate weld strength, and no empty holes (gap) are formed in the bending surface area.

[0660] Figure 15 A cross-sectional view of an electrode assembly 120 according to another embodiment of the present disclosure is shown, cut along the Y-axis direction (winding axis direction).

[0661] refer to Figure 15 Except for the height of the third part B2 having a pattern of gradually increasing and then decreasing, the electrode assembly 120 and Figure 13 The electrode assembly 100 is largely the same. The radial region of height variation in the third part B2 can be considered as the segment's height-variable region. Figure 10a (②) Even in this case, the variable height zone of the segment can be designed such that a uniform stacking zone with a segment stacking number of 10 or more appears within the aforementioned ideal numerical range in the bent surface zone F formed by bending the third part B2.

[0662] This change in the height of Part B2 can be achieved by adjusting the height of the stepped pattern (see...). Figure 6 ) or the height of the segment included in Part B2 of Section 3 (see Figure 7a or Figure 8a To implement this.

[0663] In the electrode assembly 120, the height of the first portion B1 is relatively smaller than the height of the third portion B2. Furthermore, in the third portion B2, the bending length H of the innermost uncoated portion is equal to or less than the radial length R of the first portion B1. The region corresponding to the first portion B1 corresponds to a segment skipping region without segments. Figure 10a (① in the example). In a variant, the bending length H may be less than the sum of the radial length R of the first part B1 and 10% of the radius of the core 122.

[0664] Therefore, even if the third part B2 bends towards the core, the core 122 of the electrode assembly 120 still has more than 90% of its diameter exposed to the outside. If the core 122 is not obstructed, there are no difficulties during electrolyte injection, and the electrolyte injection efficiency is improved. Furthermore, by inserting a welding jig through the core 122, the welding process between the current collector of the negative (or positive) electrode and the battery casing (or riveting terminals) can be easily performed.

[0665] Furthermore, the height of the second portion B3 is relatively smaller than the height of the third portion B2, and preferably, no segments may be formed in the second portion B3. Therefore, it is possible to prevent an internal short circuit from occurring when the rolled edge of the battery casing comes into contact with the second portion B3 when it is pressed near the second portion B3. In a variation, the height of the second portion B3 may gradually or progressively decrease towards the outer periphery.

[0666] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a variant, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (variants).

[0667] The ends 121 of the first uncoated portion 43a and the second uncoated portion 43b can be bent from the outer periphery of the electrode assembly 120 toward the core. At this time, the first portion B1 and the second portion B3 are not bent.

[0668] When the third part B2 comprises multiple segments, bending stress is relieved to prevent the uncoated portions 43a and 43b from being torn or abnormally deformed. Furthermore, when the width and / or height and / or separation distance of the segments are adjusted according to the numerical ranges of the above embodiments, the segments bend towards the core and overlap in several layers to sufficiently ensure adequate weld strength, and no empty holes (gap) are formed in the bent surface area.

[0669] Figure 16 A cross-sectional view of an electrode assembly 130 according to another embodiment of the present disclosure is shown, cut along the Y-axis direction (winding axis direction).

[0670] refer to Figure 16 Except that the height of the second part B3 has a pattern that gradually or progressively decreases from the boundary point between the second part B3 and the third part B2 toward the outermost surface of the electrode assembly 130, the electrode assembly 130 and Figure 15 The electrode assembly 120 is largely the same.

[0671] This change in height of Part B3 can be achieved by incorporating a stepped pattern included in Part B2 (see...). Figure 6The height of the pattern can be increased by extending the segmental structure of the third part B2 to the second part B3 while gradually or progressively decreasing the height of the segment towards the outer periphery. Alternatively, in another variation, the height change of the second part B3 can be implemented by extending the segmental structure of the third part B2 to the second part B3 while gradually or progressively decreasing the height of the segment towards the outer periphery.

[0672] In the electrode assembly 120, the height of the first portion B1 is relatively smaller than the height of the third portion B2. Furthermore, in the third portion B2, the bending length H of the innermost uncoated portion is equal to or less than the radial length R of the first portion B1. The first portion B1 corresponds to a segment skipping area without segments. Figure 10a (① in the example). In a variant, the bending length H may be less than the sum of the radial length R of the first part B1 and 10% of the radius of the core 132.

[0673] Therefore, even if the third part B2 bends towards the core, the core 132 of the electrode assembly 130 is open to the outside by more than 90% of its diameter. If the core 132 is not obstructed, there are no difficulties in the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the core 132, the welding process between the current collector of the negative (or positive) electrode and the battery casing (or terminal) can be easily performed.

[0674] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a variant, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (variants).

[0675] The ends 131 of the first uncoated portion 43a and the second uncoated portion 43b can be bent from the outer periphery of the electrode assembly 130 toward the core. At this time, the first portion B1 is not bent.

[0676] When the third part B2 and the second part B3 include multiple segments, bending stress can be relieved to prevent the uncoated portions 43a and 43b near the bending point from being torn or abnormally deformed. Furthermore, when the width and / or height and / or separation distance of the segments are adjusted according to the numerical ranges of the above embodiments, the segments bend towards the core and overlap in several layers to sufficiently ensure adequate weld strength, and no empty holes (gap) are formed in the bending surface area.

[0677] Meanwhile, in the aforementioned embodiment (variant example), the ends of the first uncoated portion 43a and the second uncoated portion 43b can be bent from the core toward the outer periphery. In this case, preferably, the second portion B3 is designed as a segment skipping area without segments ( Figure 10a①) and does not bend towards the outer periphery. Furthermore, the radial width of the second part B3 can be equal to or greater than the bending length of the outermost uncoated portion (or segment) of the third part B2. In this case, when the outermost uncoated portion (or segment) of the third part B2 bends towards the outer periphery, the end of the bent portion will not protrude beyond the outer periphery of the electrode assembly towards the inner surface of the battery casing. Furthermore, the structural variation pattern of the segments can be the opposite of the above embodiment (variant). For example, the height of the segments can gradually increase from the outer periphery towards the core. That is, by sequentially arranging the segment skipping area (…) from the outer periphery of the electrode assembly to the core… Figure 10a ①) The variable height region of the segment ( Figure 10a ②) and the height uniformity zone of the segment ( Figure 10a In section ③), in the bent surface region, a uniform stacking area with 10 or more segments can appear within the ideal numerical range.

[0678] Various electrode assembly structures according to one embodiment of this disclosure can be applied to cylindrical batteries.

[0679] Preferably, the cylindrical battery can be, for example, a cylindrical battery with a form factor ratio (defined as the diameter of the cylindrical battery divided by its height, i.e., the ratio of diameter (Φ) to height (H)) greater than approximately 0.4. Here, the form factor refers to the value indicating the diameter and height of the cylindrical battery.

[0680] Preferably, the cylindrical battery may have a diameter of 40 mm to 50 mm and a height of 60 mm to 130 mm. The shape factor of the cylindrical battery according to one embodiment of this disclosure may be, for example, 46110, 4875, 48110, 4880, or 4680. In the numerical values ​​representing the shape factor, the first two digits indicate the diameter of the battery, and the remaining digits indicate the height of the battery.

[0681] When an electrode assembly with a seamless structure is applied to a cylindrical battery with a form factor ratio greater than 0.4, the stress applied in the radial direction when the uncoated portion is bent is large, making the uncoated portion prone to tearing. Furthermore, when welding the current collector to the bent surface area of ​​the uncoated portion, it is necessary to sufficiently increase the number of stacked layers of the uncoated portion in the bent surface area to adequately ensure weld strength and reduce resistance. This requirement can be achieved using electrodes and electrode assemblies according to embodiments (variations) of this disclosure.

[0682] According to one embodiment of the present disclosure, the battery may be an approximately cylindrical battery with a diameter of approximately 46 mm, a height of approximately 110 mm, and a shape factor ratio of 0.418.

[0683] According to another embodiment, the battery can be an approximately cylindrical battery with a diameter of about 48 mm, a height of about 75 mm, and a shape factor ratio of 0.640.

[0684] According to another embodiment, the battery can be an approximately cylindrical battery with a diameter of approximately 48 mm, a height of approximately 110 mm, and a shape factor of 0.436.

[0685] According to another embodiment, the battery can be an approximately cylindrical battery with a diameter of approximately 48 mm, a height of approximately 80 mm, and a shape factor of 0.600.

[0686] According to another embodiment, the battery can be a cylindrical battery with an approximately cylindrical shape, having a diameter of approximately 46 mm, a height of approximately 80 mm, and a shape factor of 0.575.

[0687] Batteries with a form factor ratio of approximately 0.4 or smaller are conventionally used. That is, batteries such as 1865 and 2170 are commonly used. An 1865 battery has a diameter of approximately 18 mm, a height of approximately 65 mm, and a form factor ratio of 0.277. A 2170 battery has a diameter of approximately 21 mm, a height of approximately 70 mm, and a form factor ratio of 0.300.

[0688] The cylindrical battery according to one embodiment of the present disclosure will be described in detail below.

[0689] Figure 17 A cross-sectional view of a cylindrical battery 140 according to an embodiment of the present disclosure is shown, cut along the Y-axis.

[0690] refer to Figure 17 According to one embodiment of the present disclosure, a cylindrical battery 140 includes an electrode assembly 141 having a first electrode, a separator, and a second electrode, a battery housing 142 for housing the electrode assembly 141, and a sealing body 143 for sealing the open end of the battery housing 142.

[0691] The battery housing 142 is a cylindrical container with an opening at the top. The battery housing 142 is made of a conductive metal material such as aluminum, steel, or stainless steel. A nickel coating may be formed on the surface of the battery housing 142. The battery housing 142 houses the electrode assembly 141 within its internal space via the top opening, and also houses the electrolyte.

[0692] Electrolytes can be those with properties such as A + B - Salts with a structure of . Here, A + Including alkali metal cations, such as Li + Na + or K+ Or a combination thereof. And B - Includes at least one anion selected from the group consisting of: F - Cl - ;Br - ;I - NO3 - N(CN)2 - BF4 - ClO4 - AlO4 - AlCl4 - PF6 - SbF6 - ;AsF6 - BF2C2O4 - BC4O8 - (CF3)2PF4 - (CF3)3PF3 - (CF3)4PF2 - (CF3)5PF - (CF3)6P - CF3SO3 - C4F9SO3 - ;CF3CF2SO3 - (CF3SO2)2N - (FSO2)2N - ； CF3CF2(CF3)2CO - (CF3SO2)2CH - (SF5)3C - (CF3SO2)3C - ;CF3(CF2)7SO3 - CF3CO2 - CH3CO2 - SCN - and (CF3CF2SO2)2N - .

[0693] Electrolytes can also be dissolved in organic solvents. Organic solvents may include propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone, or mixtures thereof.

[0694] The electrode assembly 141 may have a core shape, but this disclosure is not limited thereto. Figure 2As shown, the electrode assembly 141 can be manufactured based on the winding axis C by winding a laminate formed by sequentially laminating the lower diaphragm, the first electrode, the upper diaphragm, and the second electrode at least once.

[0695] The first electrode and the second electrode have different polarities. That is, if one electrode has a positive polarity, then the other electrode has a negative polarity. At least one of the first electrode and the second electrode may have the electrode structure according to the above embodiment (variant). Furthermore, the other of the first electrode and the second electrode may have a conventional electrode structure or an electrode structure according to the embodiment (variant). The electrode pair included in the electrode assembly 141 is not limited to one electrode pair, but may include two or more electrode pairs.

[0696] 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 (variant). Therefore, in the first uncoated portion 146a, the height of the second portion B3 is less than the height of the uncoated portions in other areas. The second portion B3 is spaced apart from the inner periphery of the battery housing 142 (particularly the rolled edge portion 147) by a predetermined distance. Therefore, the second portion B3 of the first electrode does not contact the battery housing 142 electrically connected to the second electrode, thereby preventing an internal short circuit in the battery 140.

[0697] The second uncoated portion 146b of the second electrode may have the same structure as the first uncoated portion 146a. In another variation, the second uncoated portion 146b may optionally have the uncoated portion structure of the electrode according to the embodiment (variant).

[0698] The sealing body 143 may include: a cap 143a having a plate shape; a first gasket 143b for providing airtightness and insulation between the cap 143a and the battery housing 142; and a connecting plate 143c electrically and mechanically connected to the cap 143a.

[0699] The cap 143a is a component made of conductive metal material and covers the top opening of the battery casing 142. The cap 143a is electrically connected to the uncoated portion 146a of the first electrode and is electrically insulated from the battery casing 142 by means of a first gasket 143b. Therefore, the cap 143a can be used as the first electrode (e.g., the positive electrode) of the cylindrical battery 140.

[0700] The cap 143a is placed on the rolled edge 147 formed on the battery housing 142 and secured by a crimping portion 148. A first washer 143b can be inserted between the cap 143a and the crimping portion 148 to ensure the airtightness of the battery housing 142 and the electrical insulation between the battery housing 142 and the cap 143a. The cap 143a may have a protrusion 143d projecting upward from its center.

[0701] The battery casing 142 is electrically connected to the second uncoated portion 146b of the second electrode. Therefore, the battery casing 142 has the same polarity as the second electrode. If the second electrode has a negative polarity, then the battery casing 142 also has a negative polarity.

[0702] The battery housing 142 includes a rolled edge 147 and a press-fit portion 148 at its top. The rolled edge 147 is formed by press-fitting the outer periphery of the outer peripheral surface of the battery housing 142. The rolled edge 147 prevents the electrode assembly 141 housed inside the battery housing 142 from escaping through the top opening of the battery housing 142, and can also be used as a support for placing the sealing body 143 thereon.

[0703] The inner periphery of the rolled edge 147 can be spaced apart from the second portion B3 of the first electrode at a predetermined interval. More specifically, the lower end of the inner periphery of the rolled edge 147 is separated from the second portion B3 of the first electrode at a predetermined interval. Furthermore, since the second portion B3 has a low height, it is essentially unaffected even when the battery housing 142 is press-fitted externally to form the rolled edge 147. Therefore, the second portion B3 is not compressed by other components such as the rolled edge 147, thus preventing local deformation of the shape of the electrode assembly 141 and preventing short circuits inside the cylindrical battery 140.

[0704] Preferably, when the press-fit depth of the rolled edge 147 is defined as D1 and the radial length from the inner circumference of the battery housing 142 to the boundary point between the second part B3 and the third part B2 is defined as D2, the relational expression D1≤D2 can be satisfied. In this case, when the battery housing 142 is press-fitted to form the rolled edge 147, damage to the second part B3 can be largely prevented.

[0705] A crimping portion 148 is formed on the rolled edge portion 147. The crimping portion 148 has an extended and bent shape to cover the outer periphery of the cap 143a provided on the rolled edge portion 147 and a portion of the upper surface of the cap 143a.

[0706] The cylindrical battery 140 may also include a first current collector 144 and / or a second current collector 145 and / or an insulator 146.

[0707] The first current collector 144 is connected to the upper portion of the electrode assembly 141. The first current collector 144 is made of a conductive metal material such as aluminum, copper, steel, or nickel, and is electrically connected to the first uncoated portion 146a of the first electrode. The electrical connection can be formed by soldering. A lead 149 can be connected to the first current collector 144. The lead 149 can extend upwards on the electrode assembly 141 and be connected to the connecting plate 143c or directly to the lower surface of the cap 143a. The lead 149 can be connected to other components by soldering.

[0708] Preferably, the first current collector 144 can be integrally formed with the lead wire 149. In this case, the lead wire 149 can have an elongated plate shape extending outward from near the center of the first current collector 144.

[0709] The first current collector 144 may have a plurality of irregular portions (not shown) radially formed on its lower surface. When the radial irregular portions are provided, the irregular portions can be press-fitted into the first uncoated portion 146a of the first electrode by pressing the first current collector 144.

[0710] The first current collector 144 is connected to the end of the first uncoated portion 146a. The first uncoated portion 146a and the first current collector 144 can be joined, for example, by laser welding. Laser welding can be performed by locally melting the base material of the current collector 144. In a variation, the first current collector 144 and the first uncoated portion 146a can be welded with solder inserted between them. In this case, the solder can have a lower melting point than the first current collector 144 and the first uncoated portion 146a. Laser welding can be replaced by resistance welding, ultrasonic welding, spot welding, etc.

[0711] The second current collector 145 can be connected to the lower surface of the electrode assembly 141. One side of the second current collector 145 can be welded to the second uncoated portion 146b, and the other side can be welded to the inner bottom surface of the battery casing 142. The connection structure between the second current collector 145 and the second uncoated portion 146b can be substantially the same as the connection structure between the first current collector 144 and the first uncoated portion 146a.

[0712] The uncoated portions 146a and 146b are not limited to the structures shown. Therefore, the uncoated portions 146a and 146b can selectively have a conventional uncoated portion structure, or can selectively adopt the uncoated portion structure of the electrode according to the embodiment (variant).

[0713] Insulator 146 may cover the first current collector 144. Insulator 146 may cover the upper surface of the first current collector 144, thereby preventing the first current collector 144 from directly contacting the inner periphery of the battery casing 142.

[0714] The insulator 146 has a lead hole 151 through which a lead 149 extending upward from the first current collector 144 can be pulled out. The lead 149 is pulled upward through the lead hole 151 and connected to the lower surface of the connecting plate 143c or the lower surface of the cap 143a.

[0715] The peripheral region of the edge of the insulator 146 can be inserted between the first current collector 144 and the rolled edge 147 to fix the connector between the electrode assembly 141 and the first current collector 144. This restricts the movement of the connector between the electrode assembly 141 and the first current collector 144 in the Y-direction of the winding axis of the battery 140, thereby improving the assembly stability of the battery 140.

[0716] Insulator 146 may be made of an insulating polymer resin. In one embodiment, insulator 146 may be made of polyethylene, polypropylene, polyimide, or polybutylene terephthalate.

[0717] The battery casing 142 may also include an exhaust portion 152 formed on its lower surface. The exhaust portion 152 corresponds to a region with a smaller thickness compared to the peripheral region of the lower surface of the battery casing 142. The exhaust portion 152 is structurally weaker than the peripheral region. Therefore, when an anomaly occurs in the cylindrical battery 140 and the internal pressure increases above a predetermined level, the exhaust portion 152 can rupture, allowing the gas generated inside the battery casing 142 to escape to the outside. The internal pressure that causes the exhaust portion 152 to rupture can be approximately 15 kgf / cm². 2 Up to 35 kgf / cm 2 .

[0718] The vent 152 can be formed continuously or discontinuously, and a circle is drawn on the lower surface of the battery casing 142. In a variation, the vent 152 can be formed as a straight line pattern or other patterns.

[0719] Figure 18 A cross-sectional view of a cylindrical battery 150 according to another embodiment of the present disclosure is shown, cut along the Y-axis direction.

[0720] refer to Figure 18 Except for the electrode structure of the second embodiment (variant) used in the first uncoated portion 146a of the first electrode, the cylindrical battery 150 has the same... Figure 17 The cylindrical battery 140 has a largely the same configuration.

[0721] refer to Figure 18The first uncoated portion 146a of the first electrode may have a shape in which the height of the second portion B3 gradually or progressively decreases toward the inner periphery of the battery casing 142. Preferably, the imaginary line connecting the top of the second portion B3 may have the same or similar shape as the inner periphery of the rolled edge portion 147.

[0722] The second part B3 forms an inclined surface. Therefore, when the battery housing 142 is press-fitted to form the rolled edge 147, the second part B3 can be prevented from being compressed and damaged by the rolled edge 147. In addition, the phenomenon of internal short circuit caused by the second part B3 contacting the battery housing 142 with different polarities can be suppressed.

[0723] The other configurations of the cylindrical battery 150 are largely the same as those in the above-described embodiment (variant).

[0724] The uncoated portions 146a and 146b are not limited to the structures shown. Therefore, the uncoated portions 146a and 146b may selectively have a conventional uncoated portion structure, and may also selectively have an uncoated portion structure of an electrode according to the embodiment (variant).

[0725] Figure 19 A cross-sectional view of a cylindrical battery 160 according to another embodiment of the present disclosure is shown, cut along the Y-axis direction.

[0726] refer to Figure 19 Except that the lead 149 connected to the first current collector 144 passes through the lead hole 151 of the insulator 146 and is directly connected to the cap 143a of the sealing body 143, and the insulator 146 and the first current collector 144 have a structure that is in close contact with the lower surface of the cap 143a, the cylindrical battery 160 is generally the same as the cylindrical batteries 140 and 150 described above.

[0727] 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 casing 142. Furthermore, the diameter of the first current collector 144 can be equal to or greater than the outermost diameter of the third portion B2.

[0728] Specifically, the minimum inner diameter of the battery housing 142 can correspond to the inner diameter of the battery housing 142 at the location where the rolled edge 147 is formed. In this case, the outermost diameters of the first current collector 144 and the third portion B2 are smaller than the inner diameter of the battery housing 142 at the location where the rolled edge 147 is formed. Furthermore, the diameter of the first current collector 144 can be equal to or greater than the outermost diameter of the third portion B2. The peripheral region of the edge of the insulator 146 can be inserted between the second portion B3 and the rolled edge 147 while being bent downwards to fix the connection between the electrode assembly 141 and the first current collector 144.

[0729] Preferably, the insulator 146 includes 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 curved shape corresponding to the curved shape of the crimped portion 147. The insulator 146 can insulate the inner periphery of the second portion B3 from the crimped portion 147, while insulating the first current collector 144 from the inner periphery of the crimped portion 147.

[0730] The first current collector 144 can be positioned above the lower end of the rolled edge 147 and can be connected to the first portion B1 and the third portion B2. In this case, the press-fit depth (D1) of the rolled edge 147 is less than or equal to the distance (D2) from the inner circumference of the battery housing 142 to the boundary between the second portion B3 and the third portion B2. Therefore, the first portion B1, the third portion B2, and the first current collector 144 connected thereto can be positioned above the lower end of the rolled edge 147. The lower end of the rolled edge 147 refers to the bend point B between the portion of the battery housing 142 that houses the electrode assembly 141 and the rolled edge 147.

[0731] Since the first part B1 and the third part B2 occupy the internal space of the rolled edge 147 in the radial direction, the empty space between the electrode assembly 141 and the cap 143a can be minimized. Furthermore, the connecting plate 143c located in the empty space between the electrode assembly 141 and the cap 143a is eliminated. Therefore, the lead 149 of the first current collector 144 can be directly connected to the lower surface of the cap 143a. Based on the above structure, the empty space in the battery is reduced, and the energy density can be maximized according to the amount of reduced empty space.

[0732] In the cylindrical battery 160, the first current collector 144 and the second current collector 145 can be welded to the ends of the first uncoated portion 146a and the second uncoated portion 146b in the same manner as in the above embodiments.

[0733] The uncoated portions 146a and 146b are not limited to the structures shown. Therefore, the uncoated portions 146a and 146b may selectively have a conventional uncoated portion structure, and may selectively have an uncoated portion structure of an electrode according to the embodiment (variant).

[0734] Figure 20 This is a cross-sectional view showing a cylindrical battery 170 cut along the Y-axis according to one embodiment of the present disclosure.

[0735] refer to Figure 20 The structure of the electrode assembly of the cylindrical battery 170 and Figure 17 The structure of the cylindrical battery 140 is largely the same, except that the structure of other components, except for the electrode assembly, has changed.

[0736] Specifically, the cylindrical battery 170 includes a battery housing 171, through which terminals 172 are mounted. Terminals 172 are mounted through a through-hole formed in the closed surface (upper surface in the figure) of the battery housing 171. Terminals 172 are riveted to the through-hole of the battery housing 171 with a second washer 173 made of insulating material inserted between them. Terminals 172 are exposed to the outside in a direction opposite to the direction of gravity.

[0737] Terminal 172 includes a terminal exposure portion 172a and a terminal insertion portion 172b. The terminal exposure portion 172a is exposed to the outside of the closed surface of the battery housing 171. The terminal exposure portion 172a may be located approximately at the center of the closed surface of the battery housing 171. The maximum diameter of the terminal exposure portion 172a may be larger than the maximum diameter of the through hole formed in the battery housing 171. The terminal insertion portion 172b may pass through approximately the center of the closed surface of the battery housing 171 and be electrically connected to the uncoated portion 146a of the first electrode. The lower edge of the terminal insertion portion 172b may be riveted to the inner surface of the battery housing 171. That is, the lower edge of the terminal insertion portion 172b may have a shape that curves toward the inner surface of the battery housing 171. The inner side of the lower edge of the terminal insertion portion 172b includes a flat portion 172c. The maximum diameter of the lower portion of the riveted terminal insertion portion 172b may be larger than the maximum diameter of the through hole in the battery housing 171.

[0738] The flat portion 172c of the terminal insertion portion 172b can be welded to the center portion of the first current collector 144, which is connected to the first uncoated portion 146a of the first electrode. Welding can be replaced by other welding methods such as ultrasonic welding.

[0739] An insulator 174 made of insulating material can be inserted between the first current collector 144 and the inner surface of the battery casing 171. The insulator 174 covers the upper portion of the first current collector 144 and the top edge of the electrode assembly 141. Therefore, it is possible to prevent the second portion B3 of the electrode assembly 141 from contacting the inner surface of the battery casing 171, which has a different polarity, and causing a short circuit.

[0740] The thickness of the insulator 174 corresponds to or is slightly greater than the distance between the upper surface of the first current collector 144 and the inner surface of the closed portion of the battery housing 171. Therefore, the insulator 174 can contact the upper surface of the first current collector 144 and the inner surface of the closed portion of the battery housing 171.

[0741] The terminal insertion portion 172b of terminal 172 can be welded to the first current collector 144 through a through hole in insulator 174. The diameter of the through hole formed in insulator 174 can be larger than the diameter of the riveted portion at the lower end of terminal insertion portion 172b. Preferably, the through hole can expose the lower portion of terminal insertion portion 172b and the second washer 173.

[0742] A second washer 173 is inserted between the battery housing 171 and the terminal 172 to prevent the battery housing 171 and the terminal 172, which have opposite polarities, from making electrical contact with each other. Therefore, the upper surface of the battery housing 171, which has an approximately flat shape, can be used as the second electrode (e.g., the negative electrode) of the cylindrical battery 170.

[0743] The second washer 173 includes an exposed washer portion 173a and an inserted washer portion 173b. The exposed washer portion 173a is inserted between the exposed terminal portion 172a of the terminal 172 and the battery housing 171. The inserted washer portion 173b is inserted between the inserted terminal portion 172b of the terminal 172 and the battery housing 171. When the inserted terminal portion 172b is riveted, the inserted washer portion 173b can deform together to make tight contact with the inner surface of the battery housing 171. The second washer 173 can be made of, for example, an insulating polymer resin.

[0744] The gasket exposure portion 173a of the second gasket 173 may have an extended shape to cover the outer periphery of the terminal exposure portion 172a of the terminal 172. When the second gasket 173 covers the outer periphery of the terminal 172, a short circuit can be prevented when an electrical connection such as a busbar is attached to the upper surface of the battery housing 171 and / or the terminal 172. Although not shown in the figures, the gasket exposure portion 173a may have an extended shape to cover not only the outer peripheral surface of the terminal exposure portion 172a but also a portion of its upper surface.

[0745] When the second gasket 173 is made of polymer resin, it can be thermally bonded to the battery housing 171 and the terminal 172. This enhances the airtightness at the interface between the second gasket 173 and the terminal 172, as well as at the interface between the second gasket 173 and the battery housing 171. Simultaneously, when the exposed portion 173a of the second gasket 173 has a shape extending to the upper surface of the exposed portion 172a of the terminal, the terminal 172 can be integrally bonded to the second gasket 173 via insert injection molding.

[0746] On the upper surface of the battery housing 171, a portion 175, excluding the area occupied by the terminal 172 and the second washer 173, corresponds to a second electrode terminal having a polarity opposite to that of the terminal 172.

[0747] The second current collector 176 is connected to the 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.

[0748] Preferably, the second current collector 176 is electrically connected to the battery housing 171. For this purpose, at least a portion of the edge of the second current collector 176 can be inserted and fixed between the inner surface of the battery housing 171 and the first washer 178b. In one embodiment, at least a portion of the edge of the second current collector 176 can be fixed to the rolled edge 180 by welding while supported on the lower surface of the rolled edge 180 formed at the bottom of the battery housing 171. In a variation, at least a portion of the edge of the second current collector 176 can be directly welded to the inner wall surface of the battery housing 171.

[0749] The second current collector 176 may include a plurality of irregular portions (not shown) radially formed on the surface facing the second uncoated portion 146b. When the irregular portions are formed, they can be press-fitted into the second uncoated portion 146b by pressing the second current collector 176.

[0750] Preferably, the second current collector 176 and the second uncoated portion 146b can be joined by welding (e.g., laser welding). Furthermore, the welded portions of the second current collector 176 and the second uncoated portion 146b can be spaced apart by a predetermined interval based on the inner circumference of the rolled edge 180 towards the core C.

[0751] The sealing body 178 for sealing the open lower end of the battery housing 171 includes a cap 178a with a plate shape and a first washer 178b. The first washer 178b electrically separates the cap 178a from the battery housing 171. A crimping portion 181 secures the edge of the cap 178a and the first washer 178b together. The cap 178a has a venting portion 179. The configuration of the venting portion 179 is generally the same as in the above-described embodiment (variation). The lower surface of the cap 178a can be positioned above the lower end of the crimping portion 181. In this case, a space is formed below the cap 178a to facilitate venting. In particular, this is useful when the cylindrical battery 170 is mounted such that the crimping portion 181 faces the direction of gravity.

[0752] Preferably, the cap 178a is made of a conductive metal material. However, since the first gasket 178b is inserted between the cap 178a and the battery housing 171, the cap 178a is non-polar. The seal 178 seals the open end of the lower portion of the battery housing 171 and is primarily used to release gas when the internal pressure of the battery 170 increases beyond a critical value. The pressure threshold is 15 kgf / cm². 2 Up to 35 kgf / cm 2 .

[0753] Preferably, the terminal 172 electrically connected to the first uncoated portion 146a of the first electrode serves as the first electrode terminal. Furthermore, on the upper surface of the battery casing 171, in which the second uncoated portion 146b is electrically connected to the second electrode via the second current collector 176, a portion 175, excluding the terminal 172 and the second washer 173, serves as a second electrode terminal having a polarity different from the first electrode terminal. If the two electrode terminals are located on the upper portion of the cylindrical battery 170 as described above, electrical connection components such as busbars can be arranged only on one side of the cylindrical battery 170. This simplifies the battery pack structure and improves energy density. Furthermore, since the portion 175 serving as the second electrode terminal has an approximately flat shape, sufficient connection area can be ensured for connecting electrical connection components such as busbars. Therefore, the cylindrical battery 200 can reduce the resistance at the connection portion of the electrical connection components to an ideal level.

[0754] Meanwhile, the structure of the electrode assembly 141 and the structure of the uncoated portion are not limited to the structure shown, and can be replaced by the structure of the above embodiment (variant).

[0755] Figure 21 This is a cross-sectional view of a cylindrical battery 180' along the Y-axis, according to yet another embodiment of the present disclosure.

[0756] refer to Figure 21 The electrode assembly 141 of the cylindrical battery 180' has a similar design to... Figure 18 The cylindrical battery 150 shown has a generally similar structure, and the configuration is the same as that of the cylindrical battery 150 except for the electrode assembly 141. Figure 20 The cylindrical battery 170 shown has a largely the same configuration.

[0757] Therefore, the configuration of the embodiments (variations) of cylindrical batteries 150 and 170 can be equivalently applied to cylindrical battery 180'.

[0758] Furthermore, the structure of the electrode assembly 141 and the structure of the uncoated portion are not limited to those shown, and can be replaced by the structure of the above embodiments (variations).

[0759] Figure 22 This is a cross-sectional view showing a cylindrical battery 190 according to another embodiment of the present disclosure, cut along the Y-axis.

[0760] refer to Figure 22 Cylindrical battery 190 includes Figure 14 The electrode assembly 110 shown, and other configurations besides the electrode assembly 110 are similar to... Figure 17 The cylindrical battery 140 shown has a largely the same configuration. Therefore, refer to Figure 14 and Figure 17 The described configuration can be applied substantially equivalently to this implementation.

[0761] refer to Figure 10a and Figure 22 The first uncoated portion 146a and the second uncoated portion 146b of the electrode assembly 110 are bent in the radial direction of the electrode assembly 110, for example, bent from the outer periphery toward the core, to form a bent surface region F.

[0762] The first part B1 has a lower height than the other parts and corresponds to the segment skipping area a1 without segments, so it does not bend toward the core.

[0763] Preferably, the bending surface area F from the core toward the outer periphery may include a segment skipping area a1, a segment height variable area a2, and a segment height uniform area a3.

[0764] like Figure 10c , Figure 10d and Figure 10e As shown, the bending surface region F includes a uniform stacking region b1 adjacent to the segment skipping region a1, in which the number of segments stacked is 10 or more.

[0765] The bending surface region F may also include a stacking reduction region b2 adjacent to the outer periphery of the electrode assembly 110, in which the number of stacked segments decreases towards the outer periphery. Preferably, the stacking uniformity region b1 may be set as the welding target region.

[0766] In the bending surface region F, the preferred numerical ranges of the ratio (a2 / c) of the variable segment height region a2 to the radial region c containing the segment, the ratio (b1 / c) of the uniform stacking region b1 to the radial region c containing the segment, and the ratio of the area of ​​the uniform stacking region b1 to the area of ​​the bending surface region F have already been described above, so they will not be described again.

[0767] The first current collector 144 can be laser-welded to the bent surface area F of the first uncoated portion 146a, and the second current collector 145 can be laser-welded to the bent surface area F of the second uncoated portion 146b. The welding method can be replaced by ultrasonic welding, resistance welding, spot welding, etc.

[0768] Preferably, 50% or more of the area of ​​the welding region W of the first current collector 144 and the second current collector 145 may overlap with the uniform stacking area b1 of the bending surface area F. Optionally, the remaining area of ​​the welding region W may overlap with the reduced stacking area b2 of the bending surface area F. More preferably, the entire welding region W overlaps with the uniform stacking area b1 in terms of high welding strength, low resistance of the welding interface, and prevention of damage to the diaphragm or active material layer.

[0769] Preferably, in the uniform stacking area b1 overlapping with the welding area W and the optional stacking reduction area b2, the number of segments stacked can be 10 to 35.

[0770] Optionally, when the number of segments in the stack-reducing region b2 overlapping with the welding region W is less than 10, the laser output used for welding the stack-reducing region b2 can be lower than the laser output used for welding the stack-uniform region b1. That is, when the welding region W overlaps with both the stack-uniform region b1 and the stack-reducing region b2, the laser output can be varied according to the number of segments. In this case, the welding strength of the stack-uniform region b1 can be greater than the welding strength of the stack-reducing region b2.

[0771] In the bent surface regions F formed on the upper and lower portions of the electrode assembly 110, the radial lengths of the segment skipping region a1 and / or the segment height variable region a2 and / or the segment height uniform region a3 may be the same or different.

[0772] In the electrode assembly 110, the height of the first part B1 is relatively smaller than the height of the other parts. Furthermore, as... Figure 14 As shown, the bending length H of the innermost uncoated portion is less than the sum of the radial length R of the first portion B1 and 10% of the radius of the core 112.

[0773] Therefore, even if the first uncoated portion 146a is bent toward the core, the core 112 of the electrode assembly 110 can still be open to the outside by more than 90% of its diameter. If the core 112 is not obstructed, there are no difficulties in the electrolyte injection process, and the electrolyte injection efficiency is improved. Furthermore, by inserting a welding jig through the core 112, the welding process between the second current collector 145 and the battery casing 142 can be easily performed.

[0774] When the uncoated portions 146a and 146b have a segmented structure, if the width and / or height and / or separation distance of the segments are adjusted to satisfy the numerical range of the above embodiments, when the segments are bent, the segments overlap in several layers to sufficiently ensure adequate welding strength, and no empty holes (gap) are formed in the bent surface area F.

[0775] Preferably, the first current collector 144 and the second current collector 145 may have segments 61, 61' that are bent at the last winding turn covering the highly uniform region a3 of the first electrode and the second electrode. Figure 10f The outer diameter of the end of the segment. In this case, welding can be performed while the segment forming the bent surface area F is uniformly pressed by the current collector, and the tight stacking of the segments can be well maintained even after welding. Tight stacking means that there are essentially no gaps between the segments (e.g., Figure 10a(As shown in the diagram). The tight stacking configuration helps reduce the resistance of the cylindrical battery 190 to a level suitable for fast charging (e.g., 4 milliohms) or lower.

[0776] The structures of the uncoated portions 146a and 146b can be varied according to the structure described above (variant example). Furthermore, conventional uncoated portion structures can be applied to any of the uncoated portions 146a and 146b without limitation.

[0777] Figure 23 This is a cross-sectional view showing a cylindrical battery 200 according to another embodiment of the present disclosure, cut along the Y-axis direction.

[0778] refer to Figure 23 Cylindrical battery 200 includes Figure 14 The electrode assembly 110 shown, and other configurations besides the electrode assembly 110 are similar to... Figure 21 The configurations of the cylindrical batteries 180' shown are largely the same. Therefore, refer to Figure 14 and Figure 21 The described configuration can be applied substantially equivalently to this implementation.

[0779] like Figure 10a and Figure 23 As shown, the first uncoated portion 146a and the second uncoated portion 146b of the electrode assembly 110 are bent in the radial direction of the electrode assembly 110 (e.g., from the outer periphery toward the core) to form a bent surface region F.

[0780] The first part B1 has a lower height than the other parts and corresponds to the segment skipping area a1 without segments, so it does not bend toward the core.

[0781] Preferably, the bending surface region F from the core toward the outer periphery may include a segment skipping region a1, a segment height variable region a2, and a segment height uniform region a3.

[0782] like Figure 10c , 10d As shown in 10e, the bending surface region F includes a stacking quantity uniform region b1 adjacent to the segment skipping region a1, in which the number of segments stacked is 10 or more.

[0783] The bending surface region F may also include a stacking reduction region b2 adjacent to the outer periphery of the electrode assembly 110, in which the number of stacked segments decreases towards the outer periphery. Preferably, the stacking uniformity region b1 may be set as the welding target region.

[0784] In the bending surface region F, the preferred numerical ranges of the ratio (a2 / c) of the variable segment height region a2 to the radial region c including the segment, the ratio (b1 / c) of the uniform stacking region b1 to the radial region c including the segment, and the ratio of the area of ​​the uniform stacking region b1 to the area of ​​the bending surface region F have already been described above, so they will not be described again.

[0785] The first current collector 144 can be laser-welded to the bent surface area F of the first uncoated portion 146a, and the second current collector 176 can be laser-welded to the bent surface area F of the second uncoated portion 146b. The welding method can be replaced by ultrasonic welding, resistance welding, spot welding, etc. The welding area W between the second current collector 176 and the second uncoated portion 146b can be spaced apart from the inner surface of the rolled edge portion 180 by a predetermined distance.

[0786] Preferably, 50% or more of the area of ​​the welding region W of the first current collector 144 and the second current collector 145 may overlap with the uniform stacking area b1 of the bending surface area F. Optionally, the remaining area of ​​the welding region W may overlap with the reduced stacking area b2 of the bending surface area F. More preferably, the entire welding region W overlaps with the uniform stacking area b1 in terms of high welding strength, low resistance of the welding interface, and prevention of damage to the diaphragm or active material layer.

[0787] Preferably, in the uniform stacking area b1 overlapping with the welding area W and the optional stacking reduction area b2, the number of segments stacked can be 10 to 35.

[0788] Optionally, when the number of segments in the reduced stacking region b2 is less than 10, the laser output used for welding the reduced stacking region b2 can be reduced to below the laser output used for welding the uniform stacking region b1. That is, when the welding region W overlaps with both the uniform stacking region b1 and the reduced stacking region b2, the laser output can be varied according to the number of segments. In this case, the welding strength of the uniform stacking region b1 can be greater than the welding strength of the reduced stacking region b2.

[0789] In the bent surface regions F formed on the upper and lower portions of the electrode assembly 110, the radial lengths of the segment skip region a1 and / or the segment height variable region a2 and / or the segment height uniform region a3 may be the same or different.

[0790] In the electrode assembly 110, the height of the first part B1 is relatively smaller than the height of the other parts. Furthermore, as... Figure 14 As shown, the bending length H of the innermost unsegment is less than the sum of the radial length R of the first part B1 and 10% of the radius of the core 112.

[0791] Therefore, even when the uncoated portion 146a is bent toward the core, the core 112 of the electrode assembly 110 can still be open to the outside by more than 90% of its diameter. If the core 112 is not obstructed, there are no difficulties in the electrolyte injection process, and the electrolyte injection efficiency is improved. Furthermore, by inserting a welding jig through the core 112, the welding process between the first current collector 144 and the terminal 72 can be easily performed.

[0792] When the first uncoated portion 146a and the second uncoated portion 146b have a segmented structure, if the width and / or height and / or separation distance of the segments are adjusted to satisfy the numerical range of the above embodiments, when the segments are bent, the segments overlap in several layers to sufficiently ensure adequate welding strength, and no empty holes (gap) are formed in the bent surface area F.

[0793] Preferably, the regions of the first current collector 144 and the second current collector 176 that contact the first uncoated portion 146a and the second uncoated portion 146b may have segments 61, 61' that are bent at the last winding turn covering the highly uniform region a3 of the first electrode and the second electrode. Figure 10f The outer diameter of the end of the segment. In this case, welding can be performed while the segment forming the bent surface area F is uniformly pressed by the current collector, and the tight stacking of the segments can be well maintained even after welding. Tight stacking means that there are essentially no gaps between the segments (e.g., Figure 10a (As shown in the diagram). The tight stacking configuration helps reduce the resistance of the cylindrical battery 200 to a level suitable for fast charging (e.g., 4 milliohms) or lower.

[0794] The structures of the uncoated portions 146a and 146b can be varied according to the structure described above (variant example). Furthermore, conventional uncoated portion structures can be applied to any of the uncoated portions 146a and 146b without limitation.

[0795] Figure 24 This is a cross-sectional view showing a cylindrical battery 210' according to another embodiment of the present disclosure, cut along the Y-axis direction.

[0796] refer to Figure 24 Cylindrical battery 210' includes Figure 13 The electrode assembly 100 shown, and components other than the electrode assembly 100 and Figure 17 The cylindrical battery 140 shown is largely the same. Therefore, refer to Figure 13 and Figure 17 The described configuration can be applied substantially equivalently to this implementation.

[0797] Preferably, the first uncoated portion 146a and the second uncoated portion 146b of the electrode assembly 100 are divided into multiple segments, and the segments are bent in the radial direction of the electrode assembly 100, for example, bent from the outer periphery toward the core. In this case, since the first portion B1 and the second portion B3 of the first uncoated portion 146a have a lower height than the other portions and do not include segments, they are essentially not bent. The same applies to the second uncoated portion 146b.

[0798] Similarly, in this embodiment, the bending surface region F from the core towards the outer periphery may include a segment skipping region a1, a segment height variable region a2, and a segment height uniform region a3. However, since the second portion B3 is not bent, the radial length of the bending surface region F can be shorter than the radial length in the above embodiment.

[0799] like Figure 10c , Figure 10d and Figure 10e As shown, the bending surface region F includes a uniform stacking region b1 adjacent to the segment skipping region a1, in which the number of segments stacked is 10 or more.

[0800] The bending surface region F may also include a stacking reduction region b2 adjacent to the second portion B3 of the electrode assembly 110, in which the number of stacked segments gradually decreases towards the outer periphery. Preferably, the stacking uniformity region b1 may be set as the welding target region.

[0801] In the bending surface region F, the preferred numerical ranges of the ratio (a2 / c) of the variable segment height region a2 to the radial region c including the segment, the ratio (b1 / c) of the uniform stacking region b1 to the radial region c including the segment, and the ratio of the area of ​​the uniform stacking region b1 to the area of ​​the bending surface region F have already been described above, so they will not be described again.

[0802] The first current collector 144 can be laser welded to the bent surface area F of the first uncoated portion 146a, and the second current collector 145 can be laser welded to the bent surface area F of the second uncoated portion 146b.

[0803] The overlapping relationship between the uniform stacking area b1 and the reduced stacking area b2 and the welding area W, the outer diameter of the first current collector 144 and the second current collector 145, and the configuration in which 10% or more of the diameter of the core are not blocked by the first part B1 are generally the same as described above.

[0804] Meanwhile, the second part B3 does not include segments, and its height is lower than that of the third part B2. Therefore, when the first uncoated portion 146a is bent, the second part B3 does not bend substantially. Furthermore, since the second part B3 is sufficiently spaced from the crimped portion 147, the problem of damaging the second part B3 while press-fitting the crimped portion 147 can be solved.

[0805] The structures of the uncoated portions 146a and 146b can be varied according to the structure described above (variant example). Furthermore, conventional uncoated portion structures can be applied to any of the uncoated portions 146a and 146b without limitation.

[0806] Figure 25 This is a cross-sectional view showing a cylindrical battery 220 cut along the Y-axis according to one embodiment of the present disclosure.

[0807] refer to Figure 25 Cylindrical battery 220 includes Figure 24 The electrode assembly 100 shown, and components other than the electrode assembly 100 and Figure 21 The components of the cylindrical battery 180' shown are largely the same. Therefore, refer to Figure 21 and Figure 24 The described configuration can be applied substantially equivalently to this implementation.

[0808] Preferably, the first uncoated portion 146a and the second uncoated portion 146b of the electrode assembly 100 are divided into multiple segments, and the segments are bent from the outer periphery toward the core. In this case, since the first portion B1 and the second portion B3 of the first uncoated portion 146a have a lower height than the other portions and do not include segments, they are essentially not bent. The same applies to the second uncoated portion 146b.

[0809] Therefore, in this embodiment, similar to Figure 24 In this embodiment, the bending surface region F from the core toward the outer periphery may include a segment skipping region a1, a segment height variable region a2, and a segment height uniform region a3. However, since the second portion B3 is not bent, the radial length of the bending surface region F can be shorter than the radial length in the above embodiment.

[0810] like Figure 10c , Figure 10d and Figure 10e As shown, the bending surface region F includes a uniform stacking region b1 adjacent to the segment skipping region a1, in which the number of segments stacked is 10 or more.

[0811] The bending surface region F may also include a stacking reduction region b2 adjacent to the second portion B3 of the electrode assembly 110, in which the number of stacked segments decreases towards the outer periphery. Preferably, the stacking uniformity region b1 may be set as the welding target region.

[0812] In the bending surface region F, the preferred numerical ranges of the ratio (a2 / c) of the variable segment height region a2 to the radial region c including the segment, the ratio (b1 / c) of the uniform stacking region b1 to the radial region c including the segment, and the ratio of the area of ​​the uniform stacking region b1 to the area of ​​the bending surface region F have already been described above, so they will not be described again.

[0813] The first current collector 144 can be laser welded to the bent surface area F of the first uncoated portion 146a, and the second current collector 176 can be laser welded to the bent surface area F of the second uncoated portion 146b.

[0814] The overlapping relationship between the uniform stacking area b1 and the reduced stacking area b2 and the welding area W, the outer diameter of the first current collector 144 and the second current collector 176, and the configuration in which 10% or more of the core diameter is not blocked by the first part B1 are generally the same as described above.

[0815] The structures of the uncoated portions 146a and 146b can be varied according to the structure described above (variant example). Furthermore, conventional uncoated portion structures can be applied to any of the uncoated portions 146a and 146b without limitation.

[0816] In this embodiment (variant), the first current collector 144 and the second current collector 176 included in the cylindrical batteries 170, 180', 200, 220 including terminal 172 can have the following characteristics: Figure 26 and Figure 27 The improved structure shown.

[0817] The improved structure of the first current collector 144 and the second current collector 176 can help reduce the resistance of the cylindrical battery, improve vibration resistance, and increase energy density. In particular, the first current collector 144 and the second current collector 176 are more effective when used in large cylindrical batteries with a diameter-to-height ratio greater than 0.4.

[0818] Figure 26 A top plan view is shown for illustrating a first current collector 144 according to one embodiment of the present disclosure.

[0819] Let's refer to each other. Figure 23 and Figure 26The first current collector 144 may include an edge portion 144a, a first uncoated portion connecting portion 144b, and a terminal connecting portion 144c. The edge portion 144a is disposed on the electrode assembly 110. The edge portion 144a may have a generally border shape having an empty space formed therein (S open The accompanying drawings of this disclosure show only the case where the edge portion 144a has a generally circular border shape, but this disclosure is not limited thereto. The edge portion 144a may have a generally rectangular border shape, a hexagonal border shape, an octagonal border shape, or other border shapes that differ from the shown border shape. The number of edge portions 144a may be increased to two or more. In this case, the inner side of the edge portion 144a may include another edge portion in the shape of a border.

[0820] The diameter of the terminal connection portion 144c can 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 ensure the soldering area for connection with the flat portion 172c formed on the bottom surface of the terminal 172.

[0821] The first uncoated portion connecting portion 144b extends inward from the edge portion 144a and is connected to the uncoated portion 146a by welding. The terminal connecting portion 144c is spaced apart from the first uncoated portion connecting portion 144b and positioned inside the edge portion 144a. The terminal connecting portion 144c can be connected to the terminal 172 by welding. The terminal connecting portion 144c can, for example, be approximately located within the internal space (S) surrounded by the edge portion 144a. open The terminal connection portion 144c can be disposed at a position corresponding to the hole formed in the core C of the electrode assembly 110. The terminal connection portion 144c can be configured to cover the 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 outside the terminal connection portion 144c. For this purpose, the terminal connection portion 144c can have a larger diameter or width than the hole formed in the core C of the electrode assembly 110.

[0822] The first uncoated portion connecting portion 144b and the terminal connecting portion 144c may not be directly connected, but can be arranged to be spaced apart from each other and indirectly connected by means of the edge portion 144a. Since the first current collector 144 has a structure in which the first uncoated portion connecting portion 144b and the terminal connecting portion 144c are not directly connected to each other but are connected by means of the edge portion 144a as described above, the impact applied to the connecting portion between the first uncoated portion connecting portion 144b and the first uncoated portion 146a, and the connecting portion between the terminal connecting portion 144c and the terminal 172 can be dispersed when an impact and / or vibration occurs at the cylindrical battery 200. In the accompanying drawings of this disclosure, only the case where four first uncoated portion connecting portions 144b are provided is shown, but this disclosure is not limited thereto. The internal space (S) inside the edge portion 144a, considering the electrolyte impregnation, can be adjusted according to the complexity of the shape, resistance, and other factors. open Considering manufacturing difficulties, the number of first uncoated part connecting parts 144b is determined differently.

[0823] The first current collector 144 may further include a bridging portion 144d that extends inward from the edge portion 144a and connects to the terminal connection portion 144c. At least a portion of the bridging portion 144d may have a smaller cross-sectional area compared to the first uncoated connection portion 144b and the edge portion 144a. 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 connection portion 144b. In this case, the resistance in the bridging portion 144d increases. Therefore, when current flows through the bridging portion 144d, the relatively large resistance causes a portion of the bridging portion 144d to melt due to overcurrent heating. Thus, the overcurrent is irreversibly blocked. Considering the overcurrent blocking function, the cross-sectional area of ​​the bridging portion 144d can be adjusted to an appropriate level.

[0824] The bridging portion 144d may include a tapered portion 144e, the width of which gradually decreases from the inner surface of the edge portion 144a toward the terminal connection portion 144c. When the tapered portion 144e is provided, the rigidity of the component at the connection between the bridging portion 144d and the edge port...

Claims

1. An electrode assembly, wherein a first electrode, a second electrode, and a diaphragm disposed between the first electrode and the second electrode are wound based on a winding axis to define a core and an outer periphery. in, The first electrode includes a first active material portion coated with an active material layer along the winding direction and a first uncoated portion without an active material layer. The first uncoated portion includes a segmented area divided into multiple independently bendable segments by a plurality of cutting grooves arranged along the winding direction. The segment region includes multiple segments arranged at group separation intervals along the winding direction. One end of the electrode assembly includes: a plurality of segment alignment portions, wherein the plurality of segments are aligned radially; and an electrolyte impregnation portion disposed between adjacent segment alignment portions in a circumferential direction, wherein the end of the first active material portion is exposed between the winding turns of the diaphragm. The segment included in the segment alignment portion is bent toward the core to form a bent surface area. The end of the diaphragm is spaced apart from the reference line by a predetermined distance or less, and the reference line extends along the winding axis direction at a position corresponding to the bottom of the plurality of cut grooves. The preset distance is 30% of the minimum height of the segment forming the bent surface area.

2. The electrode assembly according to claim 1, in, The bent surface area has a fan-shaped shape.

3. The electrode assembly according to claim 2, in, The width of the segment group arranged in the bending surface area gradually increases from the core toward the outer periphery in the winding direction.

4. The electrode assembly according to claim 2, in, The number of segments in the segment group arranged in the bent surface area gradually or progressively increases from the core to the outer periphery.

5. The electrode assembly according to claim 1, in, The segments included in the same segment group are identical in at least one aspect selected from the width in the winding direction, the height in the winding axis direction, the lower interior angle, and the separation spacing in the winding direction.

6. The electrode assembly according to claim 1, in, In at least one aspect selected from the width in the winding direction, the height in the winding axis direction, the lower interior angle, and the separation spacing in the winding direction, the segments included in the segment group of the first winding turn are smaller than the segments included in the segment group of the second winding turn located outside the first winding turn.

7. The electrode assembly according to claim 1, in, The width, height, lower interior angle, and separation distance in the winding direction of a segment selected from a group of segments located in different winding turns gradually or progressively increase as the radius of the winding turn increases.

8. The electrode assembly according to claim 1, in, The bent surface area is rectangular, trapezoidal, or parallelogram-shaped.

9. The electrode assembly according to claim 1, in, The bent surface area and the electrolyte impregnation portion extend radially based on the core.

10. The electrode assembly according to claim 1, in, When the line connecting the center of the core to the geometric center of the pattern corresponding to the bent surface area is defined as the angle measurement line, the angles between the angle measurement lines of adjacent bent surface areas in the circumferential direction are the same.

11. The electrode assembly according to claim 10, in, The angle is 30 degrees, 40 degrees, 45 degrees, 60 degrees, 72 degrees, 90 degrees, 120 degrees or 180 degrees.

12. The electrode assembly according to claim 1, in, At least a portion of the segment group included in the segment alignment section rotates clockwise or counterclockwise based on the winding axis as the radius of the winding turn increases.

13. The electrode assembly according to claim 12, in, The amount of rotation of the segment group based on the clockwise or counterclockwise rotation of the winding axis increases as the radius of the winding turn increases.

14. The electrode assembly according to claim 1, further comprising: An insulating layer configured to cover the boundary region between the first uncoated portion and the active material layer along the winding direction. A gap is provided between the insulating layer and the cutting groove.

15. The electrode assembly according to claim 14, in, The gap varies along the winding direction.

16. The electrode assembly according to claim 15, in, In a predetermined region of the first electrode, the gap may be increased or decreased compared to the remaining region.

17. The electrode assembly according to claim 15, in, In a predetermined region of the first electrode, the gap gradually or progressively increases in a direction parallel to the winding direction.

18. The electrode assembly according to claim 14, in, The gap is 0.2 mm to 4 mm.

19. The electrode assembly according to claim 14, in, The insulating layer is exposed to the outside of the diaphragm along the winding axis.

20. The electrode assembly according to claim 15, in, The insulating layer is thinner than the active material layer and is spaced apart from the diaphragm.

21. The electrode assembly according to claim 1, in, The segment alignment portion includes a height-variable region, in which the height of the segment gradually increases from a first height h1 to a (N-1)th height h from the core of the electrode assembly toward the outer periphery. N-1 ; and a height uniformity region, in which the height of the segment remains uniform at the Nth height h. N Where N is a natural number of 3 or greater, and h N Greater than h N-1 .

22. The electrode assembly according to claim 21, in, When containing a high h k The starting radius of the winding turns of the segment is limited to r. k At that time, 90% or more of the diameter of the core of the electrode assembly is not located at r k The segment at the point is covered by the bend, where k is a natural number from 1 to N.

23. The electrode assembly according to claim 21, in, When containing height h k The starting radius of the winding turns of the segment is limited to r. k And the radius of the core is r c At that time, the height h of the segment k Satisfy the following formula: 2mm≤h k ≤r k -α*r c α ranges from 0.90 to 1. Where k is a natural number from 1 to N.

24. The electrode assembly according to claim 1, in, Based on a cross-section along the winding axis, the segment alignment portion sequentially includes a segment skipping area without segments, a height variable area for varying segment heights, and a height uniform area for uniform segment heights along the radial direction, and the plurality of segments are disposed in the height variable area and the height uniform area.

25. The electrode assembly according to claim 24, in, When the number of segments whose center of the core of the electrode assembly intersects an imaginary line parallel to the winding axis at any radius position in the bending surface region is limited to the number of segments stacked at the corresponding radius position, the bending surface region includes: a uniform stacking region, in which the number of segments stacked is uniform from the core toward the outer periphery; and a decreasing stacking region, located outside the uniform stacking region, in which the number of segments stacked decreases toward the outer periphery.

26. The electrode assembly according to claim 25, in, In the region of uniform stacking quantity, the number of stacked segments is 10 to 35.

27. The electrode assembly according to claim 25, in, The first electrode is a positive electrode, and the stacking thickness of the segments in the uniform stacking region is in the range of 100 μm to 875 μm.

28. The electrode assembly according to claim 25, in, The first electrode is a negative electrode, and the stacking thickness of the segments in the uniform stacking region is in the range of 50 μm to 700 μm.

29. The electrode assembly according to claim 1, in, The second electrode includes a second active material portion coated with an active material layer along the winding direction and a second uncoated portion without an active material layer. The second uncoated portion includes a segmented area divided into multiple independently bendable segments by a plurality of cutting grooves arranged along the winding direction. The segment region of the second uncoated portion includes a plurality of segment groups arranged at group separation intervals along the winding direction. The other end of the electrode assembly includes: a plurality of segment alignment portions, wherein the plurality of segments of the second uncoated portion are aligned along the radial direction; and an electrolyte impregnation portion disposed between adjacent segment alignment portions of the second uncoated portion along the circumferential direction, wherein the end of the second active material portion is exposed between the winding turns of the diaphragm. The segments included in the segment alignment portion of the second uncoated portion are bent toward the core to form a bent surface area. The end of the diaphragm is spaced apart from the reference line by a predetermined distance or less, and the reference line extends along the winding axis direction at a position corresponding to the bottom of the plurality of cut grooves of the second uncoated portion. The preset distance is 30% of the minimum height of the segment forming the bent surface area of ​​the second uncoated portion.

30. A battery, the battery comprising: An electrode assembly in which a first electrode, a second electrode, and a diaphragm inserted between the first and second electrodes are wound along a winding axis to define a core and an outer periphery. The first electrode includes a first active material portion coated with an active material layer along the winding direction and a first uncoated portion without an active material layer. The first uncoated portion includes a segment region divided into multiple independently bendable segments by multiple cutting grooves arranged along the winding direction. The segment region includes multiple segment groups arranged at group separation intervals along the winding direction. One end of the electrode assembly includes multiple segment alignment portions. In the segment alignment section, the plurality of segments are aligned radially; and in the electrolyte impregnation section, the electrolyte impregnation section is disposed between adjacent segment alignment sections in the circumferential direction, wherein the end of the first active material section is exposed between the winding turns of the diaphragm, including the segments in the segment alignment section being bent toward the core to form a bent surface area, the end of the diaphragm being spaced apart from a reference line by a predetermined distance or less, the reference line extending along a position corresponding to the bottom of the plurality of cutting grooves in the winding axis direction, and the predetermined distance being 30% of the minimum height of the segment forming the bent surface area; A battery housing configured to house the electrode assembly and electrically connected to one of the first electrode and the second electrode to have a first polarity; A sealing body configured to seal the open end of the battery housing; and A terminal having an externally exposed surface and electrically connected to the other of the first electrode and the second electrode to have a second polarity.

31. The battery according to claim 30, further comprising: A rolled edge portion is formed by press-fitting the peripheral region of the open end of the battery housing into the battery housing; A current collector, which is electrically connected to the bent surface area; as well as An insulator configured to cover the current collector and having an edge inserted and fixed between the inner periphery of the rolled edge and the current collector.

32. The battery according to claim 30, in, The electrode assembly has a cavity in its core, and The cavity is not blocked by the bent surface area and is open to the outside.

33. The battery according to claim 30, in, The sealing body includes: a cap configured to seal the open end of the battery housing; and a gasket configured to surround the edge of the cap and press against the top of the battery housing. The terminal having the second polarity is the cap.

34. The battery according to claim 30, further comprising: A current collector, which is electrically connected to an uncoated portion of the second electrode having the first polarity and has an edge at least partially connected to a sidewall of the battery casing. The sealing body includes: a cap, the cap being non-polar; and a gasket configured to surround the edge of the cap and press against the top of the battery housing. The battery housing includes a riveting terminal mounted to be insulated in a perforation formed at the center of the closed surface and electrically connected to the first electrode to have the second polarity.

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

36. A vehicle comprising the battery pack according to claim 35.

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