Battery and current collector applied thereto, battery pack and automobile including such battery

Abstract

According to one embodiment of the present invention, a battery includes an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding shaft to define a core and an outer circumferential surface, the first electrode including a first uncoated portion that is not coated with an active material layer along the winding direction; a battery housing having an opening on one side and accommodating the electrode assembly through the opening; a first current collector including a support disposed on an upper portion of the electrode assembly, a first tab coupling portion extending from the support and coupled to the first uncoated portion, and a first housing coupling portion extending from the support and electrically coupled to an inner surface of the battery housing; and a housing cover that seals the opening.

Description

[Technical Field]

[0001] The present invention relates to a battery, a current collector applied thereto, a battery pack including the battery, and an automobile. More specifically, the present invention relates to a current collector having a structure capable of preventing damage to a welded portion with an electrode assembly even when subjected to an external impact, a battery including the current collector, and a battery pack and an automobile including the battery.

[0002] This application is a Korean Patent Application No. 10-2021-0007278 filed on January 19, 2021, Korean Patent Application No. 10-2021-0022897 filed on February 19, 2021, Korean Patent Application No. 10-2021-0022894 filed on February 19, 2021, Korean Patent Application No. 10-2021-0022891 filed on February 19, 2021, Korean Patent Application No. 10-2021-0022881 filed on February 23, 2021, Korean Patent Application No. 10-2021-0024424 filed on March 31, 2021 Korean Patent Application No. 10-2021-0030300 filed on March 8, 2021, Korean Patent Application No. 10-2021-0030291 filed on March 8, 2021, Korean Patent Application No. 10-2021-0046798 filed on April 9, 2021, Korean Patent Application No. 10-2021-0058183 filed on May 4, 2021, Korean Patent Application No. 10-2021-0077046 filed on June 14, 2021, Korean Patent Application No. 10-2021-0084326 filed on June 28, 2021, Korean Patent Application No. 10-2021-0084326 filed on October 1, 2021 10-2021-0131225, Korean Patent Application No. 10-2021-0131215 filed on October 1, 2021, Korean Patent Application No. 10-2021-0131205 filed on October 1, 2021, Korean Patent Application No. 10-2021-0131208 filed on October 1, 2021, Korean Patent Application No. 10-2021-0131207 filed on October 14, 2021, Korean Patent Application No. 10-2021-0137001 filed on October 15, 2021 137856, Korean Patent Application No. 10-2021-0142196 filed on October 22, 2021, Korean Patent Application No. 10-2021-0153472 filed on November 9, 2021, Korean Patent Application No. 10-2021-0160823 filed on November 19, 2021, Korean Patent Application No. 10-2021-0163809 filed on November 24, 2021, Korean Patent Application No. 10-2021-0165866 filed on November 26, 2021, Korean Patent Application No. 10-2021-0172446 filed on December 3, 2021,Korean Patent Application No. 10-2021-0177091 filed on December 10, 2021, Korean Patent Application No. 10-2021-0194593 filed on December 31, 2021, Korean Patent Application No. 10-2021-0194610 filed on December 31, 2021, Korean Patent Application No. 10-2021-0194572 filed on December 31, 2021, Priority is claimed based on Korean Patent Application No. 10-2021-0194612 filed on December 31, 2021, Korean Patent Application No. 10-2021-0194611 filed on December 31, 2021, and Korean Patent Application No. 10-2022-0001802 filed on January 5, 2022, and the contents disclosed in the specifications and drawings of those applications are incorporated herein in their entirety. [Background technology]

[0003] Conventional cylindrical batteries generally have a structure in which tabs connecting the jelly roll to external terminals are welded to the foil of the jelly roll, which limits the current path and makes the resistance of the jelly roll itself very high.

[0004] Attempts have been made to reduce resistance by increasing the number of tabs connecting the jelly roll and the external terminals, but there is a limit to how much resistance can be reduced to a desired level and how much current can flow simply by increasing the number of tabs.

[0005] Therefore, in order to reduce the resistance of the jelly roll itself, there is a need to develop a new jelly roll structure and a current collector structure suitable for such a jelly roll structure. In particular, the application of such a new jelly roll structure and current collector is even more necessary in devices that require high-output / high-capacity battery packs, such as electric vehicles.

[0006] There is also a need for the development of a cylindrical battery having a structure that maintains an improved bonding strength between the current collector and the battery housing, and a current collector structure applicable to such a cylindrical battery.

[0007] Furthermore, when the current collector and the battery housing are combined, it is necessary to develop a cylindrical battery that can improve the energy density of the cylindrical battery by minimizing the dead space inside the battery housing.

[0008] In recent years, as cylindrical batteries are increasingly used in electric vehicles, the form factor of cylindrical batteries has increased. That is, the diameter and height of cylindrical batteries have increased compared to conventional cylindrical batteries with form factors such as 1865 and 2170. The increased form factor brings about increased energy density, improved safety against thermal runaway, and improved cooling efficiency.

[0009] The energy density of cylindrical batteries increases when the form factor increases and unnecessary space inside the battery housing is minimized. Therefore, the current collector must also be designed with a low resistance structure to increase the battery capacity and minimize heat generation during fast charging.

[0010] In addition, in the case of battery packs used in electric vehicles, etc., frequent exposure to vibration and shock is unavoidable considering the usage environment. Therefore, it is necessary to develop a cylindrical battery having a structure that reduces the risk of damage to welded parts even when subjected to vibration and external shock, and a current collector structure applicable to such a cylindrical battery. Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a current collector having a structure suitable for an electrode assembly having a low resistance structure, and a battery including the same.

[0012] Another object of the present invention is to provide a current collector having a structure capable of improving the bonding strength at the bonding portion between the current collector and the battery housing, and a battery including the same.

[0013] It is still another object of the present invention to provide a current collector having a structure capable of improving the energy density of a battery, and a battery including the same.

[0014] Another object of the present invention is to provide a current collector having a structure that can improve the convenience of a welding process for electrically connecting a battery housing and a current collector during battery manufacturing, thereby improving productivity, and a battery including the same.

[0015] Another object of the present invention is to provide a current collector having a structure that significantly reduces the possibility of damage occurring at the welded portion with the electrode assembly and / or the welded portion with the battery housing even when subjected to vibration and impact, and a battery including the same.

[0016] Another object of the present invention is to provide a current collector having a structure that can improve the convenience of a welding process for electrically connecting a battery housing and a current collector during battery manufacturing, thereby improving productivity, and a battery including the same.

[0017] The technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems will be clearly understood by those skilled in the art from the following description of the invention. [Means for solving the problem]

[0018] To solve the above-mentioned problems, one aspect of the present invention provides a battery comprising: an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding shaft to define a core and an outer circumferential surface, the first electrode including a first uncoated portion that is not coated with an active material layer along the winding direction; a battery housing having an opening on one side and accommodating the electrode assembly through the opening; a first current collector including a support disposed on an upper portion of the electrode assembly, a first tab coupling portion extending from the support and coupled to the first uncoated portion, and a first housing coupling portion extending from the support and electrically coupled to an inner surface of the battery housing; and a housing cover that seals the opening.

[0019] The first tab coupling portion and the first housing coupling portion may not be directly coupled to each other, but may be indirectly coupled to each other through the support portion.

[0020] The battery housing may include a beading portion formed at an end adjacent to the opening and pressed inward.

[0021] The first tab connection portion may include at least one inlet hole.

[0022] The first housing coupling portion may include a first contact portion coupled onto the beading portion of the battery housing, and a first coupling portion coupling the support portion and the first contact portion.

[0023] The first connecting portion may be disposed so that at least a portion thereof contacts the first plain portion.

[0024] The first tab coupling portion, the first connecting portion, and the first contact portion may have substantially the same width along an extension direction.

[0025] The first tab connection portion may have a width greater than that of the first connecting portion.

[0026] The first connecting portion may have a structure that is convex upward with respect to an imaginary line that connects both ends of the first connecting portion in the longitudinal direction.

[0027] The first connecting portion may have a structure that is elevated above the beading portion.

[0028] The beading portion may include an upper beading portion located above the innermost pressed point and a lower beading portion located below the innermost pressed point.

[0029] The upper and lower beading portions may be asymmetrical with respect to an imaginary reference plane that passes through the innermost points of the beading portions in parallel with the bottom surface of the battery housing.

[0030] At least one of the first tab coupling portions of the first current collector may be located below the lower beading portion.

[0031] At least one of the upper beading portion and the lower beading portion may be inclined at a predetermined angle with respect to a lower surface of the battery housing.

[0032] The first contact portion may be placed on the inclined upper surface of the beading portion.

[0033] At least one of the upper beading portion and the lower beading portion may be parallel to a lower surface of the battery housing in at least a portion thereof.

[0034] The first contact portion may be placed on a flat upper surface of the beading portion.

[0035] The first contact portion may be welded to an upper surface of the beading portion.

[0036] The first contact portion may be welded into a flat area formed on the upper beading portion.

[0037] The first contact portion may have an arc shape at least a portion of which extends in a circumferential direction along the beading portion of the battery housing, and the first contact portion may have an arc shape extending in opposite directions along the circumferential direction on the beading portion from an intersection of the first connecting portion and the first contact portion.

[0038] In the battery, the pressing depth of the beading portion is defined as PD, the minimum value of the curvature radius of the beading portion is defined as R1, min The minimum weld bead width is W bead,minThe minimum radius of curvature in the boundary region between the beading portion and the inner surface of the battery housing is R2. min Then, PD≧R1, min +R2, min +W bead,min It can be configured to satisfy the following.

[0039] The beading portion may have an indentation depth of 0.2 mm to 10 mm.

[0040] In the battery, the pressing depth of the beading portion is defined as PD, and the maximum value of the pressing depth is defined as PD max The overlap length, which is the shortest distance from the end of the first contact portion to a vertical line passing through the innermost point of the beading portion, is defined as OV, and the minimum value of the curvature radius of the beading portion is defined as R1. min The minimum weld bead width is W bead,min The minimum radius of curvature in the boundary region between the beading portion and the inner surface of the battery housing is R2. min When (R1, min +W bead,min ) / PD max ≦OV / PD≦(PD max -R2, min ) / PD max can be satisfied.

[0041] A welding area between the first contact portion and the beading portion may be formed narrower than a flat upper surface of the beading portion.

[0042] In the battery, the indentation depth of the beading portion is defined as PD, and the maximum value of the indentation depth is defined as PD max The distance from the innermost point of the beading portion to the center point of the weld bead located at the outermost periphery in the radial direction is defined as W, the overlap length that is the shortest distance from the end of the first contact portion to the vertical line passing through the innermost point of the beading portion is defined as OV, and the minimum value of OV is defined as OV. min The maximum value of OV is OV max The minimum weld bead width is W bead,min When (OVmin -0.5×W bead,min ) / PD max ≦W / PD≦(OV max -0.5×W bead,min ) / PD max can be satisfied.

[0043] The battery is such that W1 is the minimum distance from the innermost point of the beading portion to the center point of the weld bead located at the outermost edge in the radial direction, and W is the distance from the innermost point of the beading portion to the center point of the weld bead located at the outermost edge in the radial direction when the overlap length is 0V. W1 = R1 + 0.5 × W bead,min and W = OV - 0.5 × W bead,min can be satisfied.

[0044] The beading portion has a flat section parallel to the bottom surface of the battery housing in at least a portion thereof, and the length of the flat section of the beading portion in contact with the first current collector may be OV-R1 when the overlap length is OV and the radius of curvature of the beading portion is R1.

[0045] The radial width of the weld pattern formed between the beading portion and the first contact portion is W bead,min It can be more than or equal to OV-R1.

[0046] The ratio of the radial width of the welding pattern to the length of the flat section may be in the range of 10 to 40%.

[0047] The first connecting portion may include at least one first bent portion whose extension direction is changed at least once.

[0048] The first bent portion may be located above an imaginary plane that passes through the center of an imaginary line connecting one end of the first contact portion and one end of the first tab coupling portion and is parallel to the bottom surface of the battery housing.

[0049] The at least one first bent portion may be bent at an obtuse angle so as not to overlap each other when viewed from the longitudinal axis of the battery housing.

[0050] A boundary between the first contact portion and the first connecting portion may be bent at an obtuse angle.

[0051] The first connecting portion may have a shape in which the inclination thereof decreases stepwise or gradually toward the beading portion.

[0052] The angle formed between the first tab coupling portion and the first connecting portion may be in the range of 0° to 90°.

[0053] The first connector may support the housing cover.

[0054] The first tab coupling portion and the first contact portion may be positioned at substantially the same height.

[0055] The first contact portion may have a flat surface that is coupled to an upper surface of the beading portion facing the opening.

[0056] The first current collector may have a current collector hole formed in the center thereof.

[0057] The current collector hole may be provided at a position corresponding to a winding hole formed in the center of the electrode assembly.

[0058] The diameter of the current collector hole may be larger than or equal to the diameter of the winding hole provided in the core of the electrode assembly.

[0059] The first current collector may further include a second housing coupling portion extending from an end of the first tab coupling portion and coupled to an inner surface of the battery housing.

[0060] The second housing coupling portion may include a second contact portion coupled to an inner surface of the battery housing, and a second coupling portion coupling an end of the first tab coupling portion to the second contact portion.

[0061] The second contact portion may have a configuration in which at least a portion thereof extends along the inner circumferential surface of the battery housing.

[0062] The second connecting portion may include at least one second bent portion whose extension direction is changed at least once.

[0063] The distance from the center of the first current collector to the end of the first tab coupling portion may be substantially the same as or shorter than the distance from the center of the winding hole of the electrode assembly to the innermost portion of the beading portion.

[0064] The beading portion may have a flat portion on an upper surface thereof.

[0065] There may be at least one weld bead formed between the beading portion and the first contact portion, and the at least one weld bead may form a linear weld pattern extending along a circumferential direction.

[0066] At least one weld bead may be formed between the beading portion and the first contact portion, and the at least one weld bead may form an arc-shaped weld pattern extending along a circumferential direction.

[0067] The weld bead formed between the beading portion and the first contact portion may form a weld pattern, and the weld pattern may be a line shape formed by connecting spot welds.

[0068] A plurality of weld beads may be formed between the beading portion and the first contact portion within the same first contact portion.

[0069] The second electrode may further include a second uncoated portion that is not coated with an active material layer along the winding direction, and in this case, the battery may further include a terminal that penetrates the battery housing from the opposite side of the open portion and is electrically connected to the second uncoated portion.

[0070] The battery may further include a second current collector positioned between the electrode assembly and the terminal, and the second current collector may include a second tab coupling portion coupled to the second plain portion and a terminal coupling portion coupled to the terminal.

[0071] The terminal coupling portion may cover a winding hole of the electrode assembly.

[0072] The second current collector may have an outer diameter larger than that of the first current collector.

[0073] The second tab connection portion may be connected to a connection surface formed by folding the second plain portion.

[0074] The battery housing may include a crimping portion formed on the beading portion, extended and bent to enclose a peripheral edge of the housing cover.

[0075] The first housing coupling portion may be crimped and fixed by the crimping portion.

[0076] The battery may further include a sealing gasket disposed within the crimping portion and interposed between the battery housing and the housing cover.

[0077] The first contact portion may be interposed between the beading portion and the sealing gasket.

[0078] The first contact portion may be fixed by bending the crimping portion.

[0079] The sealing gasket may be thicker in an area not in contact with the first contact portion than in an area in contact with the first contact portion.

[0080] The sealing gasket may have a compressibility greater in a region that contacts the first contact portion than in a region that does not contact the first contact portion.

[0081] The sealing gasket may have a compressibility substantially equal to that of a region in contact with the first contact portion and a region not in contact with the first contact portion.

[0082] The sealing gasket may have a thickness that varies from region to region along the circumferential direction on the beading portion.

[0083] The sealing gasket may have a thickness that alternately increases and decreases along the circumferential direction on the beading portion.

[0084] The sealing gasket may have a compressibility that varies from region to region along the circumferential direction on the beading portion.

[0085] The first housing coupling portion may be resiliently biased onto the beading portion.

[0086] A connecting portion between the first contact portion and the first connecting portion may be molded to an inner surface of the beading portion.

[0087] At least a portion of the first uncoated portion may include a plurality of segments divided along the winding direction of the electrode assembly, and the plurality of segments may be folded along the radial direction of the electrode assembly to form a folded surface.

[0088] The folded segments may overlap each other to form a curved surface, and the curved surface may include an increasing layer count section in which the number of overlapping layers of the segments increases sequentially from the outer periphery of the electrode assembly toward the core until it reaches a maximum value, and a uniform layer count section from the radius point where the number of overlapping layers reaches the maximum value to the radius point where the innermost segment is located.

[0089] The first tab coupling portion may be coupled to the bent surface so as to overlap the uniform stacking number section.

[0090] The number of overlapping layers in the uniform stacking section may be 10 or more.

[0091] The first tab connection portion may be welded to the bent surface, and a welding area of ​​the tab connection portion may overlap the uniform stack number section by at least 50% along a radial direction of the electrode assembly.

[0092] The first uncoated portion and the first tab connecting portion may be connected by welding along a radial direction of the electrode assembly.

[0093] The first tab coupling portion may be welded to the first plain portion in a state parallel to a lower surface of the battery housing.

[0094] The weld bead formed between the first uncoated portion and the first tab coupling portion may form a linear weld pattern extending along a radial direction of the electrode assembly.

[0095] The weld bead formed between the first plain portion and the first tab connecting portion may form a weld pattern, and the weld pattern may be a line shape formed by connecting spot welds.

[0096] A width of a weld bead formed between the first uncoated portion and the first tab connecting portion may be 0.1 mm or more.

[0097] The first tab coupling portion and the first housing coupling portion may each be provided in a plurality, and the plurality of first tab coupling portions and first housing coupling portions may be arranged in a radial pattern, a cross pattern, or a combination thereof based on the center of the first current collector.

[0098] Each of the plurality of first housing coupling portions may be disposed between adjacent first tab coupling portions.

[0099] A plurality of the first housing coupling parts may be provided, and the first contact parts of the plurality of first housing coupling parts may be integrally formed by being connected to each other.

[0100] An outermost point of the first connecting portion may be spaced apart from an innermost point of the beading portion by a predetermined distance.

[0101] The first bent portion may cause an acute angle to be formed between the first contact portion and the first connecting portion.

[0102] A plurality of the liquid inlet holes may be provided.

[0103] The plurality of liquid injection holes may be arranged symmetrically with respect to the center of the first tab coupling portion in the width direction.

[0104] A weld bead for joining the first tab joining portion and the first uncoated portion may be formed between the liquid injection holes arranged symmetrically on the left and right.

[0105] The first tab coupling portion may be formed so that its width at a position spaced a predetermined distance from the coupling portion toward a longitudinal end of the first tab coupling portion is wider than the width at the coupling portion between the first tab coupling portion and the support portion.

[0106] The liquid injection hole may be formed at a position spaced a predetermined distance from the connecting portion toward a longitudinal end of the first tab coupling portion.

[0107] At least a portion of the area where the liquid injection hole is formed may be included in an area that is increased by increasing the width at a position spaced a predetermined distance from the connection portion toward the end of the first tab connection portion compared to the width at the connection portion between the first tab connection portion and the support portion.

[0108] The longitudinal end of the first tab coupling portion may have an arc shape corresponding to the inner circumferential surface of the battery housing.

[0109] An extension direction of a weld pattern formed between the first uncoated portion and the first tab coupling portion and an extension direction of a weld pattern formed between the beading portion and the first contact portion may be perpendicular to each other.

[0110] The innermost point of the beading portion may be located further inward in the radial direction than the end of the crimping portion.

[0111] The sealing gasket covers and wraps the housing cover, and the radial length of the portion of the sealing gasket that covers the lower surface of the housing cover may be formed shorter than the radial length of the portion of the sealing gasket that covers the upper surface of the housing cover.

[0112] When the total radial length of the first tab coupling portion is T, the outer diameter of the electrode assembly is JR, and the height of the segment disposed on the outermost contour of the electrode assembly is F, JR - 2×F ≤ T < JR may be satisfied.

[0113] The ratio of the area where the first current collector does not contact the upper surface of the electrode assembly to the area of the circle with the outer diameter of the electrode assembly as the diameter may be 30% or more and less than 100%.

[0114] The ratio of the area where the first current collector does not contact the electrode assembly to the area of the circle with the outer diameter of the electrode assembly as the diameter may be 60% or more and less than 100%.

[0115] The diameter of the current collector hole may be formed smaller than the diameter of the winding hole provided in the core of the electrode assembly.

[0116] When the diameter of the winding hole is R3, the diameter of the current collector hole may be 0.5×R3 or more and less than R3.

[0117] When the diameter of the winding hole is R3, the diameter of the current collector hole may be 0.7×R3 or more and less than R3.

[0118] The ratio of the form factor obtained by dividing the diameter of the battery by the height may be formed larger than 0.4.

[0119] In the battery, the resistance measured between the positive electrode and the negative electrode may be 4 mΩ or less.

[0120] Meanwhile, a battery according to one aspect of the present invention is an electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding shaft to define a core and an outer circumferential surface, and the first electrode may include an electrode assembly including a first uncoated portion that is not coated with an active material layer along the winding direction, a battery housing having an open portion on one side and accommodating the electrode assembly through the open portion, and a current collector electrically connected to the first uncoated portion and the inner surface of the battery housing, and the current collector may include a first portion in contact with the inner surface of the battery housing and a second portion connected to the first uncoated portion, and when a central region of the first portion is viewed from a plane on which the second portion exists, the central region of the first portion and the second portion may be spaced apart along the circumferential direction of the electrode assembly.

[0121] The battery may further include a sealing gasket interposed between the open portion of the battery housing and the current collector.

[0122] The first portion may be interposed between the inner surface of the battery housing and the sealing gasket, and the first portion and the second portion may be positioned on different planes in the winding axis direction of the electrode assembly.

[0123] Meanwhile, to solve the above-mentioned problems, a current collector according to one aspect of the present invention is a current collector that electrically connects an electrode assembly applied to a battery and a battery housing, and includes: a support portion disposed on an upper portion of the electrode assembly; a plurality of tab coupling portions extending from the support portion and coupled to first uncoated portions of the electrode assembly; and first housing coupling portions extending from the support portion and positioned between adjacent tab coupling portions, and electrically coupled to a beading portion of the battery housing.

[0124] In the current collector according to an aspect of the present invention, the tab coupling portion and the housing coupling portion may not be directly coupled to each other, but may be indirectly coupled to each other through the support portion.

[0125] The tab connection may include at least one fill hole.

[0126] The first housing coupling portion may include a first contact portion coupled to an inner surface of the battery housing, and a first coupling portion connecting the support portion and the contact portion.

[0127] The first connecting portion may include at least one first bent portion whose extension direction is changed at least once.

[0128] The current collector may have a current collector hole formed in the center thereof.

[0129] The current collector may further include a second housing coupling portion extending from an end of one of the plurality of tab coupling portions and coupled to an inner surface of the battery housing.

[0130] The second housing coupling portion may include a second contact portion coupled to an inner surface of the battery housing, and a second coupling portion connecting an end of one of the plurality of tab coupling portions to the contact portion.

[0131] The second connecting portion may be disposed so that at least a portion thereof contacts the first uncoated portion.

[0132] The first tab coupling portion, the second connecting portion, and the second contact portion may have substantially the same width along an extension direction.

[0133] The first tab connection portion may have a width greater than that of the second connection portion.

[0134] The second contact portion may have a width greater than that of the second connecting portion.

[0135] The first housing coupling parts may be provided in plurality, and the first contact parts of the first housing coupling parts may be integrally formed by being connected to each other.

[0136] The first bent portion may cause an acute angle to be formed between the contact portion and the connecting portion.

[0137] A plurality of the liquid inlet holes may be provided.

[0138] The plurality of liquid injection holes may be arranged symmetrically with respect to the center of the tab coupling portion in the width direction.

[0139] The tab coupling portion may be formed so that the width at a position spaced a predetermined distance from the coupling portion toward a longitudinal end of the tab coupling portion is wider than the width at the coupling portion between the tab coupling portion and the support portion.

[0140] The liquid injection hole may be formed at a position spaced a predetermined distance from the connecting portion toward a longitudinal end of the tab coupling portion.

[0141] At least a portion of the region in which the liquid injection hole is formed may be included in an increased region in which the width at a position spaced a predetermined distance from the connection portion toward the end of the tab connection portion is wider than the width at the connection portion between the tab connection portion and the support portion.

[0142] The longitudinal end of the tab connection portion may have an arc shape that conforms to the inner peripheral surface of the battery housing.

[0143] Meanwhile, a battery pack according to an embodiment of the present invention includes a plurality of the above-described batteries according to an embodiment of the present invention.

[0144] The plurality of batteries may be arranged in a predetermined number of rows, and the terminals of each battery and the outer surface of the bottom of the battery housing may be arranged facing upward.

[0145] The battery pack of the present invention may include a plurality of bus bars connecting a plurality of batteries in series and parallel, each of the plurality of bus bars may be disposed on top of an adjacent battery, and each of the plurality of bus bars may include a body portion extending between adjacent terminals, a plurality of first bus bar terminals extending to one side of the body portion and electrically coupled to electrode terminals of the batteries located on that side, and a plurality of second bus bar terminals extending to the other side of the body portion and electrically coupled to outer surfaces of the bottom of the battery housing of the batteries located on the other side.

[0146] A motor vehicle according to an aspect of the present invention includes the battery pack according to an aspect of the present invention described above. [Effects of the Invention]

[0147] According to one aspect of the present invention, resistance can be significantly reduced when electrically connecting an electrode assembly and a battery housing.

[0148] Furthermore, according to one aspect of the present invention, the bonding strength at the bonding site between the current collector and the battery housing can be improved.

[0149] Furthermore, according to one embodiment of the present invention, the energy density of a battery can be improved.

[0150] Furthermore, according to one aspect of the present invention, the convenience of the welding process for electrically connecting the battery housing and the current collector in the manufacture of the battery can be improved, thereby improving productivity.

[0151] Furthermore, according to one aspect of the present invention, even if vibrations and impacts are applied during the use of a battery, the possibility of damage occurring at the welded portion between the current collector and the electrode assembly and / or the welded portion between the current collector and the battery housing can be significantly reduced.

[0152] Furthermore, according to one aspect of the present invention, the convenience of the welding process for electrically connecting the battery housing and the current collector in the manufacture of the battery can be improved, thereby improving productivity.

[0153] The effects of the present invention are not limited to the above-mentioned effects, and other effects will be clearly understood by those skilled in the art from the description of the claims.

[0154] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited to only the matters described in the drawings. [Brief explanation of the drawings]

[0155] [Figure 1] 1 is a cross-sectional view showing the internal structure of a cylindrical battery according to one embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing a current collector (first current collector) according to one embodiment of the present invention. [Figure 3] 3A and 3B are diagrams illustrating exemplary shapes of first connection portions of a current collector (first current collector) according to one embodiment of the present invention. [Figure 4] 10A and 10B are views showing another exemplary form of a first connection part of a current collector (first current collector) according to an embodiment of the present invention. [Figure 5] 10 is a view showing yet another exemplary form of a first connection part of a current collector (first current collector) according to an embodiment of the present invention. FIG. [Figure 6] 10A and 10B are diagrams showing the shape of a first connection part according to the height of an electrode assembly. [Figure 7] 10A and 10B are diagrams showing the shape of a first connection part according to the height of an electrode assembly. [Figure 8] FIG. 4 is a view showing a current collector (first current collector) according to another embodiment of the present invention. [Figure 9] FIG. 10 is a view showing a current collector (first current collector) according to still another embodiment of the present invention. [Figure 10] 10A and 10B are diagrams illustrating exemplary configurations of second connecting portions of the current collector (first current collector) illustrated in FIG. 9. [Figure 11] FIG. 2 is a diagram showing a current collector (first current collector) of the present invention having a different form from the above-described embodiment. [Figure 12] FIG. 2 is a diagram showing a current collector (first current collector) of the present invention having a different form from the above-described embodiment. [Figure 13] 13 is a diagram showing the internal structure of a cylindrical battery to which the current collector (first current collector) shown in FIG. 12 is applied. FIG. [Figure 14] 1 is a plan view showing a state in which a current collector (first current collector) of the present invention is combined with a battery housing. [Figure 15] 2 is an enlarged view of the upper portion of the electrode assembly of the present invention; [Figure 16] FIG. 16 is an enlarged view of the upper part of the plain area in FIG. 15. [Figure 17] FIG. 10 is a view for explaining a welding process of a current collector (first current collector). [Figure 18] 10A and 10B are diagrams for explaining a beading process for a battery housing. [Figure 19] 10A and 10B are diagrams illustrating the crimping process of the battery housing. [Figure 20] FIG. 10 is a diagram illustrating the sizing process of the battery housing. [Figure 21] FIG. 10 is a diagram illustrating the change in shape of the current collector (first current collector) after the sizing step according to the shape of the current collector before the sizing step. [Figure 22] FIG. 10 is a diagram illustrating the shape of a current collector (first current collector) configured so that a welded region is maintained even after a sizing process. [Figure 23] FIG. 10 is a diagram illustrating the shape of a current collector (first current collector) configured so that a welded region is maintained even after a sizing process. [Figure 24] FIG. 2 is a diagram illustrating the position, length, width, etc. of a weld bead formed in a welding region between a contact portion and a beading portion of a current collector (first current collector) according to the present invention. [Figure 25] FIG. 2 is a diagram showing an embodiment of a current collector (second current collector) applied to the present invention. [Figure 26] FIG. 26 is a diagram showing a current collector (second current collector) having a different form from the current collector (second current collector) in FIG. [Figure 27]1 is a plan view illustrating an example of an electrode structure according to a preferred embodiment of the present invention; [Figure 28] 1 is a cross-sectional view taken along the longitudinal direction (Z) of an electrode assembly in which the division structure of the uncoated portion of the first electrode is also applied to the second electrode according to an embodiment of the present invention. [Figure 29] 2 is a cross-sectional view of an electrode assembly in which an uncoated portion is folded in a longitudinal direction (Z) according to an embodiment of the present invention. [Figure 30] 1 is a perspective view of an electrode assembly in which a non-coating portion is folded according to an embodiment of the present invention; [Figure 31] 1 is a top view showing a state in which a plurality of cylindrical batteries are connected in series and in parallel using bus bars according to an embodiment of the present invention. [Figure 32] 1 is a diagram showing a schematic configuration of a battery pack including a cylindrical battery according to an embodiment of the present invention; [Figure 33] 1 is a diagram showing a schematic configuration of a vehicle including a battery pack according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0156] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and claims should not be construed as being limited to their ordinary and dictionary meanings, but should be construed as having meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventor himself can appropriately define the concepts of terms in order to best explain the invention. Therefore, it should be understood that the embodiment described in this specification and the illustrated configurations are merely the most preferred embodiment of the present invention and do not represent the entire technical ideas of the present invention, and therefore, various equivalents and modifications that can be substituted therefor may exist at the time of filing this application.

[0157] In order to facilitate understanding of the invention, the accompanying drawings may not be drawn to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be used to refer to the same components in different embodiments.

[0158] The expression that two comparison objects are identical means that they are "substantially identical." Therefore, "substantially identical" may include deviations that are considered low in the art, for example, deviations within 5%. Furthermore, the expression that a parameter is uniform in a given region means that the parameter is uniform on average in that region.

[0159] Furthermore, although terms such as "first" and "second" are used to indicate various components, these terms are not intended to limit the components. These terms are used merely to distinguish one component from another, and unless otherwise specified, the first component can also be the second component.

[0160] Throughout the specification, unless otherwise stated, each element may be singular or plural.

[0161] When an arbitrary structure is placed "on (or under)" a component or "above (or below)" a component, it means not only that the arbitrary structure is placed in contact with the upper surface (or lower surface) of the component, but also that other structures may be interposed between the component and the arbitrary structure placed above (or below) the component.

[0162] Furthermore, when a component is said to be "coupled," "coupled," or "connected" to another component, it does not only mean that the components are directly coupled or connected to each other, but also that other components are "intervening" between the components, or that each component is "coupled," "coupled," or "connected" through other components.

[0163] Throughout the specification, unless otherwise specified, "A and / or B" means A, B, or A and B, and "C to D" means C or more and D or less, unless otherwise specified.

[0164] For ease of explanation, in this specification, the direction along the longitudinal direction of the winding shaft of the electrode assembly wound into a jelly roll is referred to as the axial direction (Y-axis direction). The direction surrounding the winding shaft is referred to as the circumferential direction or outer circumferential direction (X-axis direction). The direction approaching or moving away from the winding shaft is referred to as the radial direction. Of these, the direction approaching the winding shaft is referred to as the centripetal direction, and the direction moving away from the winding shaft is referred to as the centrifugal direction.

[0165] 1, a cylindrical battery 1 according to one embodiment of the present invention includes an electrode assembly 10, a battery housing 20, a current collector (first current collector) 30, a housing cover 40, and a terminal 50. The cylindrical battery 1 may further include a sealing gasket G1 and / or an insulating gasket G2 and / or a current collector (second current collector) 60 and / or an insulator 70. The present invention is not limited by the shape of the battery and can also be applied to batteries of other shapes, such as prismatic batteries.

[0166] The electrode assembly 10 includes a first uncoated region 11 and a second uncoated region 12. More specifically, the electrode assembly 10 has a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding shaft to define a core and an outer circumferential surface. That is, the electrode assembly 10 according to the present invention may have a jelly-roll structure. In this case, a separator may be further provided on the outer circumferential surface of the electrode assembly 10 for insulation from the battery housing 20. Any winding structure known in the art may be applied to the electrode assembly 10 without limitation.

[0167] The first electrode includes a first electrode current collector and a first electrode active material coated on one or both sides of the first electrode current collector. An uncoated portion where the first electrode active material is not coated is present at one end of the first electrode in the width direction (parallel to the height direction of the cylindrical battery 1 shown in FIG. 1). That is, the first electrode includes a uncoated portion at the long edge along the winding direction that is not coated with an active material and is exposed to the outside of the separator. Hereinafter, the uncoated portion functioning as the first electrode tab will be referred to as the first uncoated portion 11. The first uncoated portion 11 is provided at the upper portion in the height direction (parallel to the height direction of the cylindrical battery 1 shown in FIG. 1) of the electrode assembly 10 housed within the battery housing 20. That is, the first electrode includes a first uncoated portion at the long edge that is not coated with an active material and is exposed to the outside of the separator, and at least a portion of the first uncoated portion itself serves as the electrode tab. The first uncoated portion 11 may be, for example, a negative electrode tab.

[0168] Meanwhile, at least a portion of the first uncoated portion 11 may include a plurality of segments separated along the winding direction of the electrode assembly 10. In this case, the plurality of segments (11a in FIG. 30) may be folded along the radial direction of the electrode assembly 10.

[0169] 15 and 16 , the folded segments of the first uncoated portion 11 may overlap each other to form a folded surface (joining surface) 102. In this case, a tab coupling portion (first tab coupling portion) 32 of a current collector (first current collector) 30, which will be described later, may be coupled to the folded surface 102. The tab coupling portion 32 may be coupled to a region where the segments overlap each other. The folded surface 102 may include a layer number increasing section in which the number of overlapping layers of the segments increases gradually from the outer periphery of the electrode assembly 10 toward the core until it reaches a maximum value, and a layer number uniform section from the radius point where the number of overlapping layers reaches a maximum value to the radius point where the innermost segment is located.

[0170] In this case, welding may be performed on a certain region while the tab connector (first tab connector) 32 is placed on the bent surface 102 of the first uncoated portion 11. That is, the tab connector 32 may be bonded to a region where multiple segments of the first uncoated portion 11 are overlapped. For example, the tab connector 32 may be bonded to the bent surface 102 so as to overlap a section where the number of overlapping layers is uniform. Referring to FIG. 16 , welding of the tab connector 32 to the first uncoated portion 11 may be performed on the bent surface 102 of the first uncoated portion 11 in a region where the number of overlapping layers of the first uncoated portion 11 is approximately 10 or more. The radial ratio of the section where the number of overlapping layers is 10 or more may be designed to be approximately 25% or more based on the radius of the electrode assembly 10 excluding the core by adjusting the length of the first uncoated portion 11.

[0171] The tab coupling portion (first tab coupling portion) 32 of the current collector (first current collector) 30 may be coupled to the bent surface 102 so as to overlap the uniform stacking number section. Preferably, the tab coupling portion 32 is welded to the bent surface 102, and the welded region of the tab coupling portion 32 may overlap the uniform stacking number section by at least 50% along the radial direction of the electrode assembly 10. Preferably, the number of overlapping layers in the uniform stacking number section may be about 10 or more.

[0172] When welding the current collector 30 to the bent surface 102 of the first uncoated portion 11, it is desirable to increase the laser output to ensure sufficient welding strength. Increasing the laser output may cause the laser to penetrate the overlapping region of the first uncoated portion 11 and penetrate into the interior of the electrode assembly 10, potentially damaging the separator, active material layer, etc. Therefore, to prevent penetration by the laser, it is desirable to increase the number of overlapping layers of the first uncoated portion 11 above a certain level. Increasing the number of overlapping layers of the first uncoated portion 11 requires increasing the height of the dividing segments. However, increasing the height of the dividing segments may cause swelling of the first uncoated portion 11 during the manufacturing process of the first electrode current collector. Therefore, it is desirable to adjust the height of the dividing segments to an appropriate level.

[0173] As described above, if the ratio of the radial length where the number of overlapping layers of the uncoated segment pieces is 10 or more is designed to be 25% or more based on the radius of the electrode assembly, and the area where 10 or more uncoated segment pieces are overlapped is laser-welded to the current collector 30, the overlapping areas of the uncoated segment can sufficiently mask the laser even when the laser output is increased, preventing damage to the separator, active material layer, etc. by the laser.

[0174] Preferably, the laser output can be appropriately adjusted within a range of about 250 W to 320 W, or within a range of about 40% to 90% of the maximum laser output specification, but the present invention is not limited thereto. When the laser output satisfies the above numerical range, the welding strength can be sufficiently increased. As an example, the welding strength can be increased to 2 kgf / cm. 2 (19.6N / cm 2 ) More preferably, 4kgf / cm 2 (39.2N / cm 2 ) The welding strength can be increased to 8kgf / cm. 2 (78.5N / cm 2 ) Less than 6kgf / cm, more preferably 2 (58.8N / cm 2 ) The weld strength can be set as follows: The tensile force per unit area (kgf / cm) of the current collector 30 when the current collecting plate begins to separate from the folded surface area. 2 , N / cm 2 ) is defined as the welding strength. Specifically, after welding of the current collecting plate is completed, a tensile force is applied to the current collecting plate and the strength is gradually increased. As the tensile force increases, the uncoated area begins to separate from the weld interface. At this time, the tensile force applied to the current collector divided by the area of ​​the current collecting plate is the weld strength.

[0175] 16 is a partial cross-sectional view of an electrode assembly included in a cylindrical battery with a form factor of 4680, having a radius of 22 mm and a core radius of 4 mm, showing the first uncoated portion 11 of the first electrode current collector, which is divided into multiple segments, folded from the outer periphery toward the core, revealing a folded surface region with 10 or more overlapping layers. The electrode assembly region and core region without segments are not shown. The height of the segments starts at 3 mm and increases by 1 mm for each 1 mm increase in the radius of the electrode assembly. After reaching the illustrated lengths of 6 mm, 7 mm, or 8 mm, the height of the segments remains substantially constant.

[0176] Referring to FIG. 16, it can be seen that the number of overlapping layers in the first uncoated region 11 gradually increases from the outer periphery toward the core, and the longer the first uncoated region 11, the greater the maximum number of overlapping layers.

[0177] For example, when the length of the first uncoated region 11 is 8 mm, the number of overlapping layers of the first uncoated region 11, divided into multiple segments, increases to 18 in a 7 mm section from the outer peripheral surface of the electrode assembly. In an 8 mm section toward the core, the number of overlapping layers of the first uncoated region 11 remains at a maximum of 18, and then decreases by one or two in the radius section adjacent to the core. The height of the segments increases stepwise from 3 mm to 8 mm in a radius section from 7 mm to 12 mm. In the present invention, the uniform layer count section is defined as the radius section from the radius point where the maximum number of overlapping layers is reached to the point where the innermost segment is located, as shown in FIG. 16. Therefore, the ratio of uniform layer count sections in which 10 or more segments of the first uncoated region 11 are overlapped is 44.4% (8 / 18) of the radius of the electrode assembly excluding the core (4 mm).

[0178] As another example, when the length of the first uncoated region 11 is 7 mm, the number of overlapping layers of the first uncoated region 11 divided into multiple segments increases to 15 in a 6 mm section from the outer peripheral surface of the electrode assembly, and in a 9 mm section toward the core, the number of overlapping layers of the first uncoated region 11 remains constant at a maximum of 15, and then decreases by one or two in the radius section adjacent to the core. The height of the segments increases stepwise from 3 mm to 7 mm in a radius section from 7 mm to 11 mm. Therefore, the ratio of uniformly stacked sections with 10 or more overlapping segments of the first uncoated region 11 is 50% (9 / 18) of the radius of the electrode assembly excluding the core (4 mm).

[0179] As another example, when the length of the first uncoated region 11 is 6 mm, the number of overlapping layers of the first uncoated region 11 divided into multiple segments increases to 12 in a 5 mm section from the outer peripheral surface of the electrode assembly. In a 10 mm section toward the core, the number of overlapping layers of the first uncoated region 11 remains constant at a maximum of 12, and then decreases by one or two in the radius section adjacent to the core. The height of the segments increases from 3 mm to 6 mm in a radius section from 7 mm to 10 mm. Therefore, the ratio of uniformly stacked sections with 10 or more overlapping segments of the first uncoated region 11 is 55.6% (10 / 18) of the radius of the electrode assembly excluding the core (4 mm).

[0180] According to the embodiment, the length of the section where the number of overlapping layers increases gradually increases from 5 mm to 7 mm as the first uncoated portion 11 becomes longer, and in particular, it can be seen that the condition that the ratio of the uniform stacking number section where the number of overlapping layers is 10 or more is 25% or more based on the radius of the electrode assembly excluding the core is met.

[0181] In the present invention, the uniform stacking number section can be increased or decreased depending on the radius of the core, the minimum and maximum segment heights in the segment height variable section, and the segment height increase in the radial direction of the electrode assembly. Therefore, it is obvious that a person skilled in the art can adjust factors that affect the ratio of the uniform stacking number section to design the ratio to be 25% or more. For example, by increasing both the minimum and maximum segment heights in the segment height variable section, the ratio of the uniform stacking number section can be reduced to the 25% level as the number of overlapping layers increases.

[0182] The uniform layer count section is the region where the current collector is welded. Therefore, adjusting the ratio of the uniform layer count section to 25% or more ensures the desired welding strength of the current collector and is also advantageous in terms of resistance at the weld interface.

[0183] The second electrode includes a second electrode current collector and a second electrode active material coated on one or both sides of the second electrode current collector. The other end of the second electrode in the width direction (parallel to the height direction of the cylindrical battery 1 shown in FIG. 1) has an uncoated portion where the second electrode active material is not coated. That is, the second electrode includes a uncoated portion at the long edge along the winding direction that is not coated with an active material and is exposed to the outside of the separator. Hereinafter, the uncoated portion functioning as the second electrode tab will be referred to as the second uncoated portion 12. The second uncoated portion 12 is provided at the lower height of the electrode assembly 10 housed within the battery housing 20. That is, the second electrode includes a second uncoated portion at the long edge that is not coated with an active material and is exposed to the outside of the separator, and at least a portion of the second uncoated portion itself serves as the electrode tab. The second uncoated portion 12 may be, for example, a positive electrode tab.

[0184] Meanwhile, at least a portion of the second uncoated portion 12 may include a plurality of segments separated along the winding direction of the electrode assembly 10. In this case, the plurality of segments may be folded along the radial direction of the electrode assembly 10.

[0185] 15 and 16 , the folded second uncoated portion 12 may overlap each other to form a folded surface (joining surface) 102. In this case, a tab coupling portion (second tab coupling portion) 62 of a current collector (second current collector) 60 (described later) may be coupled to the folded surface 102. The tab coupling portion 62 may be coupled to a region where the folded second uncoated portion 12 overlaps each other. The folded surface 102 may include a layer number increasing section in which the number of overlapping layers of the folded second uncoated portion 12 gradually increases from the outer periphery of the electrode assembly 10 toward the core until it reaches a maximum value, and a layer number uniform section from the radius point where the number of overlapping layers reaches a maximum value to the radius point where the innermost folded second uncoated portion 12 exists.

[0186] The tab connection portion (second tab connection portion) 62 of the current collector (second current collector) 60 may be connected to the bent surface so as to overlap the uniform stacking number section. Preferably, the tab connection portion 62 is welded onto the bent surface 102, and the welded area of ​​the tab connection portion 62 may overlap the uniform stacking number section by at least 50% along the radial direction of the electrode assembly 10. Preferably, the number of overlapping layers in the uniform stacking number section may be about 10 or more.

[0187] When welding the first current collector 30 and / or the second current collector 60 to the substantially flat joining surface 102 formed by bending the first uncoated region 11 and / or the second uncoated region 12, it is desirable to increase the laser output to ensure sufficient welding strength. Increasing the laser output may cause the laser to penetrate the overlapping region of the first uncoated region 11 and / or the second uncoated region 12 and penetrate into the interior of the electrode assembly 10, potentially damaging the separator, active material layer, etc. Therefore, to prevent laser penetration, it is desirable to increase the number of overlapping layers of the first uncoated region 11 and / or the second uncoated region 12 above a certain level. Increasing the number of overlapping layers of the first uncoated region 11 and / or the second uncoated region 12 requires increasing the height of the division segments. However, increasing the height of the division segments may result in swells in the first uncoated region 11 and / or the second uncoated region 12 during the manufacturing process of the electrode plate. Therefore, it is desirable to adjust the height of the section to an appropriate level.

[0188] As described above, if the radial length of the section where the number of overlapping layers of the divided pieces of the first uncoated region 11 and / or the second uncoated region 12 is 10 or more is designed to be approximately 25% or more of the radius of the electrode assembly 10, and welding is performed within the welding target area, even if the laser output is increased, the overlapping portions of the first uncoated region 11 and / or the second uncoated region 12 can sufficiently mask the laser, preventing damage to the separator, active material layer, etc. by the laser.

[0189] In the present invention, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate may be any active material known in the art without any limitations.

[0190] As an example, the positive electrode active material has the general chemical formula A[A x M y ]O 2+z (A includes at least one element of Li, Na, and K; M includes at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru, and Cr; x≧0, 1≦x+y≦2, −0.1≦z≦2; the stoichiometric coefficients x, y, and z are selected to maintain electroneutrality of the compound).

[0191] As another example, the positive electrode active material may be an alkali metal compound xLiM disclosed in U.S. Pat. No. 6,677,082, U.S. Pat. No. 6,680,143, etc. 1 O2-(1-x)Li2M 2 O3(M 1 contains at least one element having an average oxidation state of 3; M 2 contains at least one element having an average oxidation state of 4; 0≦x≦1).

[0192] In yet another example, the positive electrode active material may be a compound represented by the general chemical formula Li a M 1 x Fe 1-x M 2 y P 1-y M3 z O 4-z (M 1 contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, and Al; M 2 contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V, and S; M 3 contains a halogen group element that selectively contains F; 0 < a ≤ 2, 0 ≤ x ≤ 1, 0 ≤ y < 1, 0 ≤ z < 1; the stoichiometric coefficients a, x, y, and z are selected so that the compound maintains electrical neutrality), or it can be a lithium metal phosphate represented by Li3M2(PO4)3 [M contains at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg, and Al].

[0193] Preferably, the positive electrode active material may contain primary particles and / or secondary particles formed by aggregating primary particles.

[0194] As an example, as the negative electrode active material, a carbon material, a lithium metal or a lithium metal compound, silicon or a silicon compound, tin or a tin compound, etc. can be used. Metal oxides such as TiO2 and SnO2 with a potential of less than 2V can also be used as the negative electrode active material. As the carbon material, low crystalline carbon, high crystalline carbon, etc. can be used.

[0195] As the separation membrane, a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as a polyethylene homopolymer, a polypropylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., can be used alone or by laminating these. As another example, the separation membrane can use a normal porous non-woven fabric, for example, a non-woven fabric made of high melting point glass fibers, polyethylene terephthalate fibers, etc.

[0196] At least one surface of the separator may include a coating layer of inorganic particles. Alternatively, the separator itself may be made of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are bound with a binder so that there is interstitial volume between adjacent particles.

[0197] The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. Non-limiting examples of the inorganic particles include Pb(Zr,Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg3Nb 2 / 3 )O3-PbTiO3 (PMN-PT), BaTiO3, hafnia (HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO, and Y2O3.

[0198] The electrolyte is A + B - where A + Li + , Na + , K. + or a combination thereof. - is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , BF2C2O4 - , BC4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 -, (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - The anion comprises one or more anions selected from the group consisting of:

[0199] The electrolyte may be dissolved in an organic solvent such as propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone, or a mixture thereof.

[0200] Referring to FIG. 1, the battery housing 20 is a generally cylindrical container having an opening on one side and is made of a conductive metal material. The side surface of the battery housing 20 and the bottom surface (the bottom surface in FIG. 1) located opposite the opening are generally formed integrally. That is, the battery housing 20 generally has an open upper end in its height direction and a closed lower end. The bottom surface of the battery housing 20 may have a generally flat shape. The battery housing 20 receives the electrode assembly 10 through an opening formed on one side in its height direction (Z-axis direction). The battery housing 20 may also receive an electrolyte through the opening.

[0201] The battery housing 20 may include a beading portion 21 formed at an end adjacent to an opening formed at an upper end of the battery housing 20. The battery housing 20 may further include a crimping portion 22 formed on the beading portion 21. The beading portion 21 has a shape in which the periphery of the battery housing 20 is pressed to a predetermined depth. More specifically, the beading portion 21 may have a shape in which the periphery of the battery housing 20 is pressed inward in a region between an opening formed on one side of the battery housing 20 and a receiving portion that receives the electrode assembly 10.

[0202] The indentation depth of the beading portion 21 may be, for example, about 0.2 mm to 10 mm. The minimum value of the indentation depth PD of the beading portion 21 is determined by the curvature radius R1 of the beading portion 21 and the width W of the weld bead. bead , and the radius of curvature R2 at the boundary region between the beading portion 21 and the inner surface of the battery housing 20 must all be taken into consideration. For example, referring to Figure 24, in order for welding to be possible, additional space is required in addition to the radius of curvature R1 of the beading portion 21 and the radius of curvature R2 at the boundary region between the beading portion 21 and the inner surface of the battery housing 20. If the pressing depth PD is R1 + R2, this is because there is no flat section F on the beading portion 21. Furthermore, in order for welding to be possible, the additional space required is the minimum width W of the weld bead BD. bead,min Therefore, the minimum value of the indentation depth PD must satisfy the following formula 1.

[0203] [Formula 1] PD ≥ R1, min +R2, min +W bead,min

[0204] For example, R1, min and R2, min The minimum values ​​of are approximately 0.05 mm, and W bead,min is about 0.1 mm, the minimum value of the indentation depth PD may be about 0.2 mm or more.

[0205] In another embodiment, the maximum value of the indentation depth PD of the beading portion 21 may vary depending on the material and thickness of the battery housing 20. As an example, when the material of the battery housing 20 is steel and the maximum thickness of the battery housing 20 is approximately 1 mm, the maximum value of the indentation depth PD of the beading portion 21 may be approximately 10 mm. Therefore, in one example, the indentation depth PD of the beading portion 21 may have a value of approximately 0.2 mm to 10 mm.

[0206] The beading portion 21 is formed on the upper portion of the electrode assembly 10. The inner diameter of the battery housing 20 in the area where the beading portion 21 is formed is smaller than the diameter of the electrode assembly 10. The beading portion 21 may include an upper beading portion located above the innermost point where the battery housing 20 is pressed in, and a lower beading portion located below the innermost point where the battery housing 20 is pressed in. At least one tab coupling portion 32 of the current collector 30, which will be described later, may be located below the lower beading portion.

[0207] At least one of the upper beading portion and the lower beading portion may be inclined at a predetermined angle with the lower surface of the battery housing 20. In this case, the first contact portion 33a of the current collector (first current collector) 30, which will be described later, may be placed on the inclined upper surface of the upper beading portion of the beading portion 21.

[0208] Alternatively, at least one of the upper beading portion and the lower beading portion may have at least a portion that is substantially parallel to the lower surface of the battery housing 20. In this case, the first contact portion 33a of the current collector 30, which will be described later, may be placed on the substantially flat upper surface of the upper beading portion. The first contact portion 33a may have a flat surface that is coupled with the upper surface of the beading portion 21 that faces the open portion of the battery housing 20. Here, the upper surface of the beading portion 21 refers to the surface that faces the open portion.

[0209] The beading portion 21 provides a support surface on which the housing cover 40 is placed. The beading portion 21 may also provide a support surface on which at least a portion of the end of the current collector 30 (described later) is placed and coupled. That is, at least a portion of the end of the current collector 30 and / or the peripheral edge of the housing cover 40 may be placed on the upper surface of the upper beading portion. To stably support at least a portion of the end of the current collector 30 and / or the peripheral edge of the housing cover 40, the upper surface of the upper beading portion may extend in a direction substantially parallel to the lower surface of the battery housing 20, i.e., in a direction substantially perpendicular to the sidewall of the battery housing 20. The beading portion 21 may be omitted, and at least a portion of the end of the current collector 30 may be directly attached to the flat sidewall of the battery housing 20.

[0210] 20 together with FIG. 1 , the beading portion 21 may include upper and lower beading portions located above and below the innermost portion located in the pressing direction. The upper and lower beading portions may have asymmetric shapes. Specifically, the upper and lower beading portions may have asymmetric shapes based on an imaginary reference plane that passes through the innermost point of the beading portion parallel to the bottom surface of the battery housing 20. This asymmetric shape may be formed during a sizing process, in which the battery housing 20 is compressed in the height direction (direction parallel to the Z-axis) of the battery housing 20. The sizing process is a process in which the battery housing 20 is compressed along the winding axis direction of the electrode assembly 10 to adjust the height of the cylindrical battery 1 to the design form factor.

[0211] The upper beading portion may have a flat portion that is approximately parallel to the closure of the battery housing 20. Meanwhile, due to its asymmetrical shape, the lower beading portion may have a shape that is at least partially inclined downward toward the innermost portion. As a result, the lower beading portion can press and fix the upper portion of the electrode assembly 10. The beading portion 21 prevents the electrode assembly 10, which has a size that approximately corresponds to the inner diameter of the battery housing 20, from slipping out of the opening formed at the upper end of the battery housing 20, and can also function as a support portion on which the housing cover 40 is placed. The upper beading portion can function as a support portion for fixing not only the housing cover 40 but also the first contact portion 33a of the current collector (first current collector) 30, the sealing gasket G1, etc.

[0212] The crimping portion 22 is formed on the beading portion 21. The crimping portion 22 is extended and bent to enclose the peripheral edge of the housing cover 40 disposed on the beading portion 21. The shape of the crimping portion 22 allows the housing cover 40 to be fixed onto the beading portion 21. Of course, the crimping portion 22 may be omitted, and the housing cover 40 may be fixed while covering the opening of the battery housing 20 using another fixing structure. The innermost point of the beading portion 21 may be located radially inward of the electrode assembly 10 relative to the end point of the crimping portion 22. For example, referring to FIG. 1, the end point of the crimping portion 22 may be located radially outward compared to the innermost point of the beading portion 21. This structure allows the beading portion 21 to remain relatively flat even after the sizing process. If the innermost point of the beading portion 21 is located radially further outward than the end point of the crimping portion 22, the radial length of the upper surface of the crimping portion 22 will be longer than the radial length of the beading portion 21. This will increase the area of ​​the upper surface of the crimping portion 22, which is the part that receives pressure during the sizing process, and this may cause the beading portion 21 to not be flat after the sizing process.

[0213] Hereinafter, the current collector (first current collector) 30 according to one embodiment of the present invention will be described in detail with reference to FIGS.

[0214] 1 and 2, a current collector 30 according to an embodiment of the present invention is housed inside a battery housing 20 and is electrically connected to the electrode assembly 10 and the battery housing 20. That is, the current collector 30 electrically connects the electrode assembly 10 and the battery housing 20.

[0215] The current collector 30 includes a support portion 31 located on one side of the electrode assembly 10, a plurality of tab coupling portions (first tab coupling portions) 32 coupled to the first plain portion 11, and a plurality of first housing coupling portions 33 extending from the support portion 31 and coupled to the inner surface of the battery housing 20. The tab coupling portions 32 and the first housing coupling portions 33 are indirectly connected to each other through the support portion 31 and are not directly connected to each other. Therefore, when an external impact is applied to the cylindrical battery 1 of the present invention, damage to the coupling portions between the current collector 30 and the electrode assembly 10 and the coupling portions between the current collector 30 and the battery housing 20 can be minimized. At least one tab coupling portion 32 and / or one first housing coupling portion 33 may be provided. The at least one tab coupling portion 32 and the at least one first housing coupling portion 33 may be arranged, for example, in a radial pattern, a cross pattern, or a combination thereof, based on the center of the current collector 30. In another embodiment, each of the plurality of first housing coupling portions 33 may be disposed between adjacent tab coupling portions 32 .

[0216] The support portion 31 and the plurality of tab coupling portions 32 are disposed on the upper portion of the electrode assembly 10. The tab coupling portions 32 are coupled to the first non-coated portion 11 of the electrode assembly 10. The tab coupling portions 32 may be coupled to the first non-coated portion 11 by welding, for example, along the radial direction of the electrode assembly 10. The tab coupling portions 32 may be welded to the first non-coated portion 11, for example, in a state substantially parallel to the lower surface of the battery housing 20. The weld beads formed between the first non-coated portion 11 and the tab coupling portions 32 may form, for example, a substantially linear weld pattern extending along the radial direction of the electrode assembly 10. The weld pattern may be, for example, a linear shape formed by connecting spot welds. The weld pattern may include one pattern or two or more patterns extending along the radial direction of the electrode assembly 10.

[0217] Meanwhile, not only the tab coupling portion 32 but also the support portion 31 may be coupled to the first uncoated portion 11. The tab coupling portion 32 and the first uncoated portion 11 may be coupled by welding. When a beading portion 21 is formed on the battery housing 20, the support portion 31 and the tab coupling portion 32 are located below the beading portion 21.

[0218] The support part 31 may have a current collector hole H2 formed at a position corresponding to a winding hole H1 formed at approximately the center of the electrode assembly 10. The winding hole H1 and the current collector hole H2, which are connected to each other, may function as a passage for inserting a welding rod for welding between a terminal 50 and a current collector (second current collector) 60 (described later) or between the terminal 50 and a lead tab (not shown), or for irradiating a laser beam. The current collector hole H2 may have a diameter substantially the same as or larger than the diameter of the winding hole H1 of the electrode assembly 10 so as not to block the winding hole H1 formed in the core of the electrode assembly 10. If the diameter of the current collector hole H2 is excessively smaller than the diameter of the winding hole H1, the winding hole H1 may be blocked, reducing the ability to inject liquid, and it may be difficult to ensure sufficient space for inserting a welding device or irradiating a laser.

[0219] Alternatively, according to another embodiment of the present invention, the diameter of the current collector hole H2 may be smaller than the diameter of the winding hole H1. In this case, for example, when the diameter of the winding hole H1 is R3, the diameter of the current collector hole H2 may be greater than or equal to about 0.5×R3 and less than R3, and preferably greater than or equal to about 0.7×R3 and less than R3. Generally, when venting occurs, gas is discharged from the winding center of the electrode assembly 10, and strong pressure may cause the separator and uncoated portion near the winding center to be pushed out from the top surface of the electrode assembly 10. In this case, if the diameter of the current collector hole H2 is smaller than the diameter of the hole provided in the core of the electrode assembly 10, the separator and uncoated portion near the winding center can be prevented from detaching from the electrode assembly 10. However, if the diameter of the current collector hole H2 is too small, there is a risk that the electrolyte injection property will be reduced. In order to ensure space for the welding operation between the second current collector 60 and the terminal 50, the diameter of the current collector hole H2 is preferably about 0.5×R3 or more, and more preferably 0.7×R3 or more.

[0220] The plurality of tab coupling portions 32 may extend radially from the support portion 31 of the current collector 30 toward the sidewall of the battery housing 20. Each of the plurality of tab coupling portions 32 may be spaced apart from one another around the periphery of the support portion 31. To ensure bonding strength and reduce electrical resistance by increasing the bonding area between the current collector 30 and the electrode assembly 10, not only the tab coupling portions 32 but also the support portion 31 may be coupled to the first uncoated portion 11. At least a portion of the first uncoated portion 11 may be formed such that its end portion is bent substantially parallel to the tab coupling portions 32. In this case, the bending may be performed, for example, toward the winding center C of the electrode assembly 10. When the end portion of the first uncoated portion 11 is formed and coupled to the tab coupling portion 32 in a parallel state, the bonding area is increased, thereby improving bonding strength and reducing electrical resistance, and the overall height of the electrode assembly 10 is minimized, thereby improving energy density. Meanwhile, the folded end of the first uncoated region 11 may overlap in multiple places. When the first uncoated region 11 overlaps in multiple places, the tab coupling portion 32 of the current collector 30 is coupled to the coupling surface 102 (see FIGS. 15 and 16) formed by folding the first uncoated region 11 in multiple places, as described above.

[0221] The plurality of first housing coupling portions 33 may extend radially from the support portion 31 of the current collector 30 toward the sidewall of the battery housing 20. The plurality of first housing coupling portions 33 may be spaced apart from one another around the periphery of the support portion 31. At least one first housing coupling portion 33 may be located between adjacent tab coupling portions 32. The plurality of first housing coupling portions 33 may be coupled to, for example, the beading portion 21 on the inner surface of the battery housing 20. The first housing coupling portion 33 may be coupled to the upper surface of the beading portion 21. When this structure is applied to the cylindrical battery 1 of the present invention, the first housing coupling portions 33 may naturally be placed on the beading portion 21 through the process of placing the electrode assembly 10, to which the current collector 30 is coupled, into the battery housing 20. This facilitates the welding process between the battery housing 20 and the current collector 30. For example, laser welding, ultrasonic welding, or spot welding may be used to couple the battery housing 20 and the current collector 30 together. By welding the first housing coupling part 33 onto the beading part 21 to form multiple current paths, the resistance level can be limited to approximately 4 mΩ or less, which is suitable for fast charging. In addition, the upper surface of the beading part 21 extends in a direction approximately parallel to the lower surface of the battery housing 20, i.e., in a direction approximately perpendicular to the sidewall of the battery housing 20, and the first housing coupling part 33 also extends in the same direction, i.e., in the radial and circumferential directions, so that the first housing coupling part 33 can be stably contacted with the beading part 21. In addition, the stably contacting of the first housing coupling part 33 with the beading part 21 allows smooth welding between the two parts, thereby improving the bonding strength between the two parts and minimizing the increase in resistance at the bonding site.

[0222] 3 to 7, the first housing coupling portion 33 includes a first contact portion 33a coupled to the inner surface of the battery housing 20, and a first connecting portion 33b connecting the support portion 31 and the first contact portion 33a. The first connecting portion 33b may be disposed so that at least a portion thereof contacts the first plain portion 11. The first connecting portion 33b and the first contact portion 33a may have substantially the same width along the extension direction. The first tab coupling portion 32 may have a width wider than the first connecting portion 33b. The first contact portion 33a may have a width wider than the first connecting portion 33b.

[0223] The first contact portion 33a is coupled to the inner surface of the battery housing 20. If the beading portion 21 is formed on the battery housing 20, the first contact portion 33a may be coupled to the beading portion 21 as described above. In this case, for stable contact and coupling, the beading portion 21 and the first contact portion 33a may all extend in a direction substantially parallel to the bottom surface of the battery housing 20, i.e., a direction substantially perpendicular to the sidewall of the battery housing 20, as described above. In addition, although not shown, a coupling portion between the first contact portion 33a and the first connecting portion 33b may be aligned with the inner surface of the beading portion 21. That is, the shape of the coupling portion between the first contact portion 33a and the first connecting portion 33b may be configured to match the shape of the beading portion 21 at a corresponding position. In this case, when the first housing coupling portion 33 is coupled to the beading portion 21, the coupling force between the first housing coupling portion 33 and the beading portion 21 is increased, and the increased contact area enhances the effect of reducing resistance. Meanwhile, the outermost point of the first connecting portion 33b may be spaced apart from the innermost point of the beading portion 21 by a predetermined distance.

[0224] The first connecting portion 33b may have at least one first bent portion B1 where the extension direction thereof is changed at least once between the support portion 31 and the first contact portion 33a. The first connecting portion 33b may have, for example, a spring-like or bellows-like structure that is capable of contracting and expanding within a certain range. This structure of the first connecting portion 33b allows the first contact portion 33a to be closely attached to the beading portion 21 during the process of inserting the electrode assembly 10, to which the current collector 30 is coupled, into the battery housing 20, even if the height of the electrode assembly 10 varies within a certain range.

[0225] For example, it is preferable that the vertical distance D between the first contact portion 33a and the support portion 31 when no external force is applied to the current collector 30 and the current collector 30 is not deformed be substantially the same as the vertical distance D between the upper surface of the beading portion 21 and the support portion 31 when the electrode assembly 10, to which the current collector 30 is coupled, is placed in the battery housing 20, or be smaller within the extensible range of the first connecting portion 33b. That is, the first housing coupling portion 33 may be elastically biased onto the beading portion 21. More specifically, the first housing coupling portion 33 may be coupled onto the beading portion 21 while storing elastic energy capable of deforming in a direction that reduces the linear distance from one end to the other end of the first connecting portion 33b in the longitudinal direction. If the first connecting portion 33b is configured to satisfy this condition, the first contact portion 33a will naturally come into close contact with the beading portion 21 when the electrode assembly 10, to which the current collector 30 is coupled, is placed in the battery housing 20.

[0226] Furthermore, the contractible and extensible first connecting portion 33b structure can absorb, within a certain range, the impact caused by the movement of the electrode assembly 10, even if vibration and / or impact occurs during use of the cylindrical battery 1 (see FIG. 1) and causes the electrode assembly 10 to move up and down. In other words, the contractible and extensible first connecting portion 33b structure can act as a buffer to prevent impact from being transmitted to the connection portion between the first contact portion 33a and the battery housing 20 and the connection portion between the tab connection portion 32 and the first plain portion 11 (see FIGS. 1 to 5).

[0227] Meanwhile, the first contact portion 33a may be welded to an upper surface (upper surface of the upper beading portion) of the beading portion 21. Furthermore, the first contact portion 33a may be welded to a flat region on the upper surface of the beading portion 21. The welded region between the first contact portion 33a and the beading portion 21 may be narrower than the flat upper surface of the beading portion 21. If the first bent portion B1 is provided, the angle between the first contact portion 33a and the first connecting portion 33b may be an acute angle due to the first bent portion B1.

[0228] Referring now to Figure 8, a current collector 30 according to another embodiment of the present invention is shown. The current collector 30 according to this embodiment of the present invention differs from the current collector 30 described above (the current collector described with reference to Figure 2) only in the shape of the first contact portion 33a, and otherwise the structure of the current collector 30 described above can be applied in substantially the same manner.

[0229] 1 and 8, the first contact portion 33a may have an arc shape with at least a portion extending in the circumferential direction along the beading portion 21 of the battery housing 20. Thus, the circumferential length of the first contact portion 33a may be longer than the width of the first connecting portion 33b. In this case, to maximize the contact area, the current collector 30 may be configured such that the sum of the circumferential lengths of the first contact portions 33a of the plurality of first housing coupling portions 33 is substantially the same as or slightly shorter than the inner circumference of the battery housing 20. In another embodiment, the first contact portion 33a may have an arc shape extending in opposite directions along the circumferential direction on the beading portion 21 from the intersection of the first connecting portion 33b and the first contact portion 33a.

[0230] 9 and 10 in addition to Fig. 1, a current collector 30 according to yet another embodiment of the present invention is shown. The current collector 30 according to yet another embodiment of the present invention differs from the current collector 30 of the above-described embodiment (the current collector described with reference to Figs. 2 and 8) only in that it further includes a second housing coupling portion 34, but otherwise the structure of the current collector 30 (see Fig. 9) described above can be applied in substantially the same manner.

[0231] The second housing coupling portion 34 extends from an end of the tab coupling portion 32 and is coupled to the inner surface of the battery housing 20. The second housing coupling portion 34 may be provided at an end of at least one of the plurality of tab coupling portions 32. The second housing coupling portion 34 includes a second contact portion 34a coupled to the inner surface of the battery housing 20 and a second connecting portion 34b connecting the end of the tab coupling portion 32 to the second contact portion 34a. The second connecting portion 34b may be positioned such that at least a portion of the second connecting portion 34b contacts the first plain portion 11. The first tab coupling portion 32, the second connecting portion 34b, and the second contact portion 34a may have substantially the same width along the extension direction. The first tab coupling portion 32 may have a width wider than the second connecting portion 34b. The second contact portion 34a may have a width wider than the second connecting portion 34b.

[0232] The second contact portion 34a is coupled to the inner surface of the battery housing 20. If a beading portion 21 is formed on the battery housing 20, the second contact portion 34a may be coupled to the beading portion 21, similar to the first contact portion 33a described above. In this case, as described above, for stable contact and coupling, the beading portion 21 and the second contact portion 34a may all extend in a direction substantially parallel to the bottom surface of the battery housing 20, i.e., in a direction substantially perpendicular to the sidewall of the battery housing 20.

[0233] Meanwhile, although not shown, like the shape of the first contact portion 33a shown in Fig. 8, at least a portion of the second contact portion 34a may also have a shape that extends in the circumferential direction along the beading portion 21 of the battery housing 20. As a result, the circumferential length of the second contact portion 34a may be longer than the width of the second connecting portion 34b. In this case, to maximize the contact area between the current collector 30 and the battery housing 20, the current collector 30 may be configured such that the sum of the circumferential lengths of the first contact portions 33a of the plurality of first housing coupling portions 33 and the sum of the circumferential lengths of the second contact portions 34a of the plurality of second housing coupling portions 34 is substantially the same as or slightly shorter than the inner circumference of the battery housing 20.

[0234] Similar to the first connecting portion 33b described above, the second connecting portion 34b may have at least one second bent portion B2 where the extension direction of the second connecting portion 34b is changed at least once between the tab coupling portion 32 and the second contact portion 34a. The formation of the second bent portion B2 allows the second connecting portion 34b to have a contractible and expandable structure, which provides advantages and cushioning effects in the assembly process of the cylindrical battery 1, as described above.

[0235] Although the drawings show a case where one second bending portion B2 is provided, the present invention is not limited thereto, and similar to the first connecting portion 33b described above with reference to Figures 4 and 5, multiple second bending portions B2 may also be provided.

[0236] FIG. 11 illustrates a current collector 30 having yet another configuration. Referring to FIG. 11 together with FIG. 1, the current collector (first current collector) 30 of the present invention may have at least one liquid inlet hole H3. The liquid inlet hole H3 may be provided, for example, in the tab coupling portion 32. When a plurality of tab coupling portions 32 are provided, the liquid inlet hole H3 may be provided in at least one of the tab coupling portions 32. The liquid inlet hole H3 may be provided, for example, on one or both sides of at least one weld bead W formed on the tab coupling portion 32. Referring to FIGS. 1 and 11, in manufacturing a cylindrical battery 1 according to an embodiment of the present invention, an assembly including the electrode assembly 10 and the current collector (first current collector) 30 may be placed in the battery housing 20, and then electrolyte may be injected. The liquid inlet hole H3 may improve the liquid inlet performance.

[0237] A plurality of the liquid injection holes H3 may be provided in one tab coupling portion 32. The plurality of liquid injection holes H3 may be arranged approximately symmetrically on the left and right sides with respect to the center of the width direction of the tab coupling portion 32. A weld bead W for joining the tab coupling portion 32 and the first uncoated portion 11 may be formed between the liquid injection holes H3 arranged approximately symmetrically on the left and right sides.

[0238] The tab coupling portion 32 may be formed so that its width at a position spaced a predetermined distance from the connection portion toward a longitudinal end of the tab coupling portion is wider than its width at the connection portion between the tab coupling portion 32 and the support portion 31. At least a portion of the region where the liquid injection hole H3 is formed may be included within an increased region resulting from the width at a position spaced a predetermined distance from the connection portion toward the end of the tab coupling portion 32 being wider than its width at the connection portion between the tab coupling portion 32 and the support portion 31. Meanwhile, the longitudinal end of the tab coupling portion 32 may be substantially arc-shaped to correspond to the inner circumferential surface of the battery housing 20.

[0239] 12 and 13, the first connecting portion 33b of the first housing coupling portion 33 and / or the second connecting portion 34b of the second housing coupling portion 34 of the present invention may be bent once, and may be bent in a direction different from that shown in FIGS. 3 and 10. That is, the first bent portion B1 formed on the first connecting portion 33b and / or the second bent portion B2 formed on the second connecting portion 34b may be bent in a direction protruding toward the center of the cylindrical battery 1 (see FIG. 1). The bending direction of the first connecting portion 33b and / or the second connecting portion 34b is intended to prevent damage to the coupling portion between the current collector (first current collector) 30 and the electrode assembly 10 and / or the coupling portion between the current collector (first current collector) 30 and the battery housing 20 during the sizing process. The sizing process is a compression process that reduces the height of the beading portion 21 area of ​​the battery housing 20 during the manufacture of the cylindrical battery 1, thereby reducing the overall height of the cylindrical battery 1. Experiments were conducted to confirm the degree of damage to the welded joints after the sizing process by changing the formation of the bends B1 and B2 and the protruding direction of the bends B1 and B2. As a result, it was confirmed that almost no damage occurred in cylindrical batteries 1 with a structure in which the bends B1 and B2 protrude toward the center of the cylindrical battery 1.

[0240] 17 to 20 show some steps of manufacturing the cylindrical battery 1 of the present invention. First, referring to FIG. 17, after placing the current collector 30 on the electrode assembly 10 housed inside the battery housing 20, the first uncoated portion 11 protruding upward from the electrode assembly 10 is welded to the current collector 30. In this case, the plurality of divided pieces 11a (see FIG. 30 15 ) is bent, the tab joint 32 of the current collector 30 is welded to the bent surface 102. Alternatively, the current collector 30 may be welded to the bent surface 102 in advance before the electrode assembly 10 is placed inside the battery housing 20.

[0241] 18, with the current collector 30 welded onto the electrode assembly 10, the beading knife is moved into the battery housing 20. As a result, a beading portion 21 is formed on the side wall of the battery housing 20, the beading portion 21 being pressed into the battery housing 20, and the beading portion 21 is positioned below the contact portion (first contact portion) 33a of the current collector 30. Therefore, the contact portion 33a and the beading portion 21 are positioned so that they can be welded.

[0242] 19 together with FIG. 18, the contact portion 33a of the current collector 30 may be placed on the upper surface of the beading portion 21. With the current collector 30 placed on the upper surface of the beading portion 21, the current collector 30 and the beading portion 21 may be welded together. A housing cover 40, the edge of which is covered by a sealing gasket G1, may be placed on the upper surface of the contact portion 33a. The battery housing 20 is then folded to enclose the peripheral edge of the housing cover 40, thereby fixing the housing cover 40 and the current collector 30 together. The crimping portion 22 is formed by folding the area of ​​the battery housing 20 above the beading portion 21, and the contact portion 33a of the housing cover 40 and the current collector 30 is fixed onto the beading portion 21 due to the extended and folded shape of the crimping portion 22. The first housing coupling portion 33 may be crimped and fixed by the crimping portion 22.

[0243] Meanwhile, in the present invention, the extension direction of the weld pattern formed between the first non-coating portion 11 and the tab coupling portion 32 may be substantially perpendicular to the extension direction of the weld pattern formed between the beading portion 21 and the first contact portion 33a. For example, the extension direction of the weld pattern formed between the first non-coating portion 11 and the tab coupling portion 32 may be the radial direction of the electrode assembly 10, and the extension direction of the weld pattern formed between the beading portion 21 and the first contact portion 33a may be the circumferential direction of the electrode assembly 10 (or the battery housing 20). In this case, a tangent drawn at any point in the circumferential direction is perpendicular to the radial direction. This structure increases the bonding strength between the current collector 30 and the electrode assembly 10 and between the current collector 30 and the battery housing 20. That is, this structure allows the current collector 30 to maintain a firm attachment to the electrode assembly 10 and the battery housing 20, respectively, even when vibrations and / or impacts are applied to the cylindrical battery 1 from any direction.

[0244] Referring now to FIG. 20 in conjunction with FIG. 19, a cylindrical battery whose overall height has been adjusted by a sizing process is shown. The sizing process is a compression process during the manufacture of a cylindrical battery, in which the height occupied by the beading portion 21 of the battery housing 20 is reduced to decrease the overall height of the cylindrical battery. The sizing process compresses the battery housing 20 in the height direction (Z-axis direction), which may result in the beading portion 21 of the electrode assembly 10 being pressed and partially compressed. Alternatively, the sizing process compresses the battery housing 20 in the longitudinal direction (vertical direction), which may result in the current collector 30 warping due to pressure in the vertical direction. That is, as the sizing process progresses, the tab coupling portion 32 may warp upward, potentially damaging the weld between the tab coupling portion 32 and the first uncoated portion 11. Therefore, the current collector 30 needs to have a structure that prevents damage to the weld between the tab coupling portion 32 and the first uncoated portion 11 even after the sizing process.

[0245] For example, when the connecting portion (first connecting portion) 33b has an upwardly convex shape as shown in Fig. 22, the effect of suppressing the phenomenon of the tab coupling portion 32 lifting up as shown in Fig. 20 is maximized. That is, when the battery housing 20 of Fig. 19 is compressed in the vertical direction, the bending of the connecting portion 33b causes upward stress to act on the tab coupling portion 32. However, when the connecting portion 33b has a generally upwardly convex shape as in the current collector 30, the stress applied to the tab coupling portion 32 is minimized. Therefore, the tab coupling portion 32 does not lift up, and the welded state of the weld with the first uncoated portion 11 is maintained in a good condition.

[0246] 22 and 23, the connecting portion 33b before the sizing process may have a convex shape extending upward relative to an imaginary line connecting the connecting point between the contact portion 33a and the connecting portion 33b and the connecting point between the connecting portion 33b and the tab coupling portion 32, i.e., an imaginary line connecting both longitudinal ends of the connecting portion 33b. For example, the connecting portion 33b may have at least one bent portion B1 forming an obtuse angle. The bent portion B1 may be located above an imaginary plane that passes through the approximate center of the imaginary line connecting both ends of the connecting portion 33b and is parallel to the bottom surface of the battery housing 20. Preferably, the length of the connecting portion 33b from the bent portion B1 to the tab coupling portion 32 may be longer than the length of the connecting portion 33b from the bent portion B1 to the contact portion 33a.

[0247] According to this structure, during the sizing process, which is subjected to vertical pressure, the contact portion 33a descends downward as shown by the arrow, and the connecting portion 33b ascends upward as shown by the arrow (see dotted line). More specifically, the connecting portion 33b ascends higher than the beading portion 21. That is, the profile of the first housing coupling portion 33 changes before and after the sizing process, as shown in FIGS. 22 and 23. The degree to which the connecting portion 33b ascends may vary depending on the change in height of the battery housing 20 caused by the sizing process. Meanwhile, unlike the illustration, the position of the bent portion B1 may ascend to the same height as the contact portion 33a. As a result of the connecting portion 33b ascending upward, most of the stress is absorbed by the connecting portion 33b, and the stress applied to the welded region between the tab coupling portion 32 and the first non-coating portion 11 is relatively small. Therefore, according to the present invention, the tab coupling portion 32 does not ascend upward. Furthermore, according to the structure described above, the length of the connecting portion 33b from the bent portion B1 to the tab connection portion 32 is longer than the length of the connecting portion 33b from the bent portion B1 to the contact portion 33a, making it easier to insert the current collector 30 into the battery housing 20 and effectively dispersing stress.

[0248] Meanwhile, the shape change due to the elevation of the connecting portion 33b may be performed in a substantially curved shape that is convex upward as shown in Fig. 22, or alternatively, it may be performed in a linear shape bent based on the bending portion B1 as shown in Fig. 23. When bent in a linear shape as shown in Fig. 23, in the connecting portion 33b, the region from the bending portion B1 to the contact portion 33a and the region from the bending portion B1 to the tab coupling portion 32 may each have a linear shape.

[0249] The inventors have studied the structure of the current collector 30 that can prevent twisting and / or lifting of the current collector 30, and have found that if the connecting portion 33b has an upwardly convex structure, damage to the welded portion between the tab connecting portion 32 and the first uncoated portion 11 during the sizing process is significantly reduced.

[0250] FIG. 21 is a diagram for comparing the degree of damage to the welded portion depending on the shape of the current collector 30 before the sizing process. Referring to FIG. 21, Experimental Example 1 is an experimental example in which the connecting portion 33b before sizing was linear, Experimental Example 2 is an experimental example in which the connecting portion 33b before sizing was convex downward, and Experimental Example 3 is an experimental example in which the connecting portion 33b before sizing was convex upward. A 1-mm sizing process was performed on Experimental Examples 1 to 3. In Experimental Example 1, in which the connecting portion 33b was linear, the welded region to the tab coupling portion 32 rose by approximately 0.72 mm. In Experimental Example 2, in which the connecting portion 33b was convex downward, the welded region to the tab coupling portion 32 rose by approximately 0.99 mm. That is, it was confirmed that the lifting phenomenon was more severe when the connecting portion 33b was convex downward than when the connecting portion 33b was linear. On the other hand, in Experimental Example 3, in which the connecting portion 33b was convex upward, the welded area with the tab coupling portion 32 lifted up by about 0.02 mm. This means that the lifting phenomenon was significantly reduced compared to Experimental Examples 1 and 2. That is, in Experimental Example 3, in which the connecting portion 33b was convex upward, it was confirmed that damage to the welded area between the tab coupling portion and the first uncoated portion was minimized. This is because the degree of lifting of the current collector 30 varies depending on the stress applied by the current collector 30 to the electrode assembly 10. That is, in Experimental Example 1, in which the connecting portion 33b was linear, and Experimental Example 2, in which the connecting portion 33b was convex downward, it was confirmed that the lifting phenomenon of the current collector 30 was severe because the stress applied to the welded area between the current collector 30 and the electrode assembly 10 during the sizing process was very large, about 4.5 MPa and 3.7 MPa, respectively. On the other hand, in Experimental Example 3, in which the connecting portion 33b is convex upward, the stress applied to the welded portion between the current collector 30 and the electrode assembly 10 during the sizing process was approximately 2.0 MPa, which is relatively low compared to Experimental Examples 1 and 2, and therefore the lifting phenomenon of the current collector 30 occurred relatively less frequently.

[0251] Therefore, as shown in FIG. 22, the inclination of the connecting portion 33b may be inconsistent, and the inclination in the upper region may be smaller than the inclination in the lower region based on a predetermined point (e.g., a bent portion B1). The predetermined point may be located above the middle of the connecting portion 33b. Alternatively, the connecting portion 33b may have an upward convex shape based on an imaginary line connecting the tab coupling portion 32 and the contact portion 33a. The convex shape may be a combination of two straight lines, a curved line, or a combination of these. For example, as shown in FIG. 22 or 23, the connecting portion 33b may have at least one bent portion B1 based on the predetermined point. Preferably, the at least one bent portion B1 may be bent at an obtuse angle so as not to overlap each other when viewed from the longitudinal axis of the battery housing 20. Meanwhile, the boundary between the contact portion 33a and the connecting portion 33b may be bent at an obtuse angle. As a result, the inclination of the connecting portion 33b may decrease stepwise or gradually toward the beading portion 21.

[0252] In yet another embodiment of the present invention, referring to FIG. 20 , the angle θ between the tab connecting portion 32 and the connecting portion 33b may be, for example, 0° to 90°. For example, if the upper end of the electrode assembly 10 is raised to a height corresponding to the beading portion 21 during the sizing process, the tab connecting portion 32 and the contact portion 33a may be positioned at the same height. This corresponds to the case where the angle θ between the tab connecting portion 32 and the connecting portion 33b is approximately 0°. Even after the sizing process, it is undesirable for the contact portion 33a to be positioned lower than the tab connecting portion 32. This is because the first non-coating portion 11 may be damaged by excessive pressure from the beading portion 21. Therefore, it is preferable that the angle θ between the tab connecting portion 32 and the connecting portion 33b be greater than 0°. In another embodiment, the angle θ between the tab connecting portion 32 and the connecting portion 33b may increase to approximately 90° depending on the shape of the connecting portion 33b, in which the length, thickness, or inclination changes stepwise or gradually. However, in order to avoid contact with the housing cover 40, it is preferable that the angle θ does not exceed 90°.

[0253] In yet another embodiment of the present invention, the connecting portion 33b may support the housing cover 40. For example, the connecting portion 33b may be curved upward as a result of a sizing process. In this case, the curved connecting portion 33b may come into contact with the housing cover 40. In this case, the connecting portion 33b may serve to support the housing cover 40 upward. Therefore, the current collector 30 is securely fixed in the vertical direction as a result of the sizing process. As a result, even if vibrations and / or impacts occur during use of the cylindrical battery 1, unnecessary vertical movement of the electrode assembly 10 within the battery housing 20 can be prevented.

[0254] In yet another embodiment of the present invention, the upper surface and the lower surface of the beading portion 21 may be asymmetric with respect to an imaginary reference plane that passes through the innermost point of the beading portion 21 and is parallel to the bottom surface of the battery housing. For example, referring to Fig. 20, when the battery housing 20 is compressed in the vertical direction during the sizing process, the beading portion 21 is also compressed in the vertical direction. In this case, the upper surface and the lower surface of the beading portion 21 may be asymmetric with respect to an imaginary reference plane (see dashed line) that passes through the innermost point of the beading portion 21.

[0255] In yet another embodiment of the present invention, the indentation depth of the beading portion 21 may be defined as PD. For example, referring to FIG. 24, the indentation depth PD may be defined as the vertical distance from the inner surface of the battery housing 20 to the innermost point of the beading portion 21. Meanwhile, the shortest distance from the end of the contact portion 33a to a vertical line passing through the innermost point of the beading portion 21 may be defined as the overlap length OV. That is, referring to FIG. 24, the overlap length OV refers to the radial length of the area where the beading portion 21 and the current collector 30 overlap when viewed from above the beading portion 21. In this case, the cylindrical battery 1 of the present invention may satisfy the following Equation 2.

[0256] [Formula 2] (R1, min +Wbead,min ) / PD max ≦OV / PD≦(PD max -R2, min ) / PD max

[0257] In order for the contact portion 33a of the current collector 30 to be placed on the beading portion 21 in a weldable manner, the above ratio must be (R1, min +W bead,min ) / PD max 24, in order for the contact portion 33a of the current collector 30 to be placed on the beading portion 21 in a weldable manner, an overlapping region longer than the radius of curvature R1 of the beading portion 21 is required. For example, if the contact portion 33a is overlapped only with the radius of curvature R1 of the beading portion 21, there is no flat section, and the contact portion 33a and the beading portion 21 come into contact with only one point of contact. In other words, the contact portion 33a cannot be stably placed on the beading portion 21. Therefore, the contact portion 33a requires an additional overlapping region in addition to the radius of curvature R1 of the beading portion 21, and in this case, the length of the additional overlapping region must be at least the weld bead width W. bead That is, in the additional overlapping region, the contact portion 33a substantially overlaps with the beading portion 21, and welding can be performed in this region. Therefore, the length of the additional overlapping region is at least the weld bead width W bead If the overlap length is less than this, stable welding cannot be performed without departing from the overlapping area. In other words, the minimum overlap length for the contact portion 33a to be placed on the beading portion 21 in a weldable manner is R1. min +W bead,min becomes.

[0258] In another embodiment, in order for the contact portion 33a of the current collector 30 to be weldably placed on the beading portion 21, the above ratio (PD max -R2, min ) / PD max24, there is a radius of curvature R2 in the boundary region between the beading portion 21 and the inner surface of the battery housing 20. Therefore, when the contact portion 33a of the current collector 30 enters the boundary region between the beading portion 21, which has the radius of curvature R2, and the inner surface of the battery housing 20, the radius of curvature R2 prevents the contact portion 33a from adhering to the beading portion 21 and causes the contact portion 33a to float up. Therefore, the maximum overlap length for the contact portion 33a to be placed on the beading portion 21 in an adherable manner is PD max -R2, min becomes.

[0259] As an example, the maximum value PD of the pressing depth PD of the beading portion 21 is max can be about 10 mm, and R1, min and R2, min The minimum values ​​of W and W can be about 0.05 mm each. bead,min The ratio of the overlap length OV to the indentation depth PD of the beading portion 21 may be in the range of about 1.5 to 99.5%. In order for the contact portion 33a of the current collector 30 to be weldably placed on the beading portion 21, it is desirable that the ratio be about 1.5% or more. The lower limit of the OV / PD ratio is the maximum indentation depth PD of the beading portion 21. max , the minimum value of the radius of curvature R1, min , and the minimum width of the contact portion 33a that comes into contact with the upper surface of the beading portion 21 for welding of the contact portion 33a, i.e., the minimum width W of the weld bead BD. bead,min Specifically, in one example, the maximum value of the indentation depth PD max The minimum contact width of the contact portion 33a required for welding the contact portion 33a, i.e., the minimum width W of the weld bead BD, is 10 mm. bead,min The length is 0.1 mm, and the minimum value of the curvature radius R1 is R1, min Under this condition, the minimum overlap length OV is 0.15 mm (= 0.1 mm + 0.05 mm), and PD maxSince the contact depth is 10 mm, the lower limit of the OV / PD ratio is 1.5%. Meanwhile, the point where the contact portion 33a of the current collector 30 makes maximum contact with the flat portion of the upper surface of the beading portion 21 is a point spaced apart from the inner surface of the battery housing by the radius of curvature R2. Therefore, when the end of the contact portion 33a is located at this point, the overlap length OV is maximized. The upper limit of the OV / PD ratio is determined by the maximum value of the pressing depth and the minimum value R2 of the radius of curvature R2. min Specifically, the maximum value of the indentation depth is 10 mm, and the minimum value of the curvature radius R2 is 0.05 mm. Under these conditions, the maximum value of the overlap length OV is 9.95 mm (= 10 mm - 0.05 mm), and PD max is 10 mm, the upper limit of the OV / PD ratio is 99.5%.

[0260] In yet another embodiment of the present invention, the welding position where the beading portion 21 and the contact portion 33a are welded may be defined as W. More specifically, the welding position W may refer to the distance from the innermost point of the beading portion 21 to the center point of the weld bead BD located at the outermost position in the radial direction. In this case, the welding position W and the plunge depth PD may satisfy the following Equation 3.

[0261] [Formula 3] (OV min -0.5×W bead,min ) / PD max ≦W / PD≦(OV max -0.5×W bead,min ) / PD max

[0262] The welding position W between the beading portion 21 and the contact portion 33a is determined by the overlap length between the contact portion 33a and the beading portion 21 and the minimum width W of the weld bead BD. bead,min The weld position W is the center point of the weld bead BD.

[0263] 24, the welding position when the contact portion 33a overlaps the beading portion 21 to a minimum extent can be defined as W1. The overlap length at this time is determined by the OVmin On the other hand, if the weld bead BD is not formed within the overlapping area, stable welding cannot be performed, so the weld bead BD must be completely contained within the overlapping area. Therefore, the welding position W1 is set to OV min from at least 0.5 × W bead,min The point is spaced inward from the beading portion 21 by . Therefore, W1 can satisfy the following Equation 4.

[0264] [Formula 4] W1=OV min -0.5×W bead,min =R1, min +W bead,min -0.5×W bead,min =R1, min +0.5×W bead,min

[0265] On the other hand, in order for the value of W1 / PD to be minimum, the value of PD should be maximum, so the minimum value of W / PD is (OV min -0.5×W bead,min ) / PD max becomes.

[0266] In another embodiment, referring to Fig. 24, the welding position when the contact portion 33a penetrates the beading portion 21 to the maximum extent can be defined as W2. The overlap length at this time is determined by the OV max On the other hand, if the weld bead BD is not formed in the overlapping area, stable welding cannot be performed, so the weld bead BD must be completely contained within the overlapping area. Therefore, the welding position W2 is OV max from at least 0.5 × W bead,min The distance W2 is a point spaced inward from the beading portion 21 by 1 / 2. Therefore, W2 satisfies the following Equation 5.

[0267] [Formula 5] W2=OV max -0.5×W bead,min =PD max -R2, min -0.5×Wbead,min

[0268] On the other hand, in order to maximize the value of W2 / PD, (PD max -R2, min -0.5×W bead,min ) divided by PD, {1-(R2, min +0.5×W bead,min ) / PD} should be maximized. That is, when the PD value is maximized, the W2 / PD value is also maximized. Therefore, the maximum value of W / PD is (OV min -0.5×W bead,min ) / PD max becomes.

[0269] For example, the minimum width required to weld the contact portion 33a to the beading portion 21 may be 0.1 mm. That is, the width of 0.1 mm corresponds to the minimum width of the weld bead BD that can be formed by laser welding. Therefore, the welding position W1 when the contact portion 33a contacts the top surface of the beading portion 21 with the minimum width is (R1, min +0.5 × 0.1 mm) away from the target. min is the minimum value of the radius of curvature R1, for example, 0.05 mm. When a laser is irradiated onto this point, a weld bead BD having a width of 0.1 mm is formed on the contact surface between contact portion 33a and beading portion 21. The width of weld bead BD also corresponds to the minimum contact width of contact portion 33a. Based on the indentation depth PD of beading portion 21, welding position W1 is a point 0.1 mm away from the innermost point of beading portion 21.

[0270] On the other hand, when the contact portion 33a contacts the upper surface of the beading portion 21 at the maximum width, the end of the contact portion 33a is spaced apart from the inner surface of the battery housing by a radius of curvature R2, min where R2, minis the minimum value of the radius of curvature R2, for example, 0.05 mm. In this case, the welding position W2 that can be closest to the end of the contact portion 33a is a point 0.05 mm away from the end of the contact portion 33a. By irradiating the laser at this point, a welding bead with a minimum width of 0.1 mm can be formed by abutting against the end of the contact portion 33a. The welding position W2 when the contact portion 33a makes contact with the top surface of the beading portion 21 at the maximum width is (PD-R2, min -0.05mm). For example, R2, min When the distance W2 is 0.05 mm, the maximum value of the welding position W2 is a point spaced apart by PD-0.1 mm from the innermost point of the beading portion 21.

[0271] According to the above explanation, R1, min and R2, min When the distance PD is 0.05 mm, the welding position W of the contact portion 33a based on the indentation depth PD can be set in the range of (0.1 mm) to (PD-0.1 mm) based on the innermost point of the beading portion 21. The ratio of the welding position W1 based on the indentation depth PD occurs when the indentation depth PD is at its maximum value, so the minimum value (%) of W1 / PD is 1% (= 100 × 0.1 mm / 10 mm). The maximum value of the ratio W1 / PD of the welding position W2 based on the indentation depth PD occurs when PD is at its maximum value, so the maximum value (%) of W2 / PD is 99% (= 100 × (10 mm-0.1 mm) / 10 mm). In summary, the welding position range based on the indentation depth PD can be a range of 1% to 99% based on the indentation depth PD.

[0272] 24, when the overlap length is OV, the distance from the innermost point of the beading portion 21 to the center point of the outermost weld bead BD in the radial direction can be defined as W. In this case, the cylindrical battery 1 of the present invention can satisfy the following Equation 6.

[0273] [Formula 6] W=OV-0.5×W bead,min

[0274] In another embodiment, the beading portion 21 has a flat section F that is parallel to the bottom surface of the battery housing 20 in at least a portion thereof, and the length of the flat section F of the beading portion 21 that contacts the current collector 30 may be OV-R1. That is, referring to FIG. 23, the flat section F corresponds to the length obtained by subtracting the radius of curvature R1 of the beading portion 21 from the overlap length OV.

[0275] In yet another embodiment of the present invention, when the overlap length is OV, the radial width of the welding pattern, which is a set of weld beads BD formed between the beading portion 21 and the contact portion 33a, is W bead,min It can be more than or equal to OV-R1.

[0276] Referring to FIG. 24, the minimum width of the weld bead BD is W bead,min Therefore, the minimum value of the radial width of the welding pattern formed between the beading portion 21 and the contact portion 33a is at least W bead,min Meanwhile, a plurality of weld beads BD may be formed over the entire area of ​​the flat section F of the beading portion 21. At this time, the plurality of weld beads BD may form a uniform weld pattern. 24 Referring to the formula (7), the maximum value of the radial width of the welding pattern formed between the beading portion 21 and the contact portion 33a may satisfy the formula (7) below.

[0277] [Formula 7] The maximum value of the radial width of the weld pattern formed between the beading portion 21 and the contact portion 33a = W-W1 + Minimum width of weld bead BD =[(OV-0.5×W bead,min )-(R1+0.5×W bead,min )]+W bead,min =OV-R1

[0278] In yet another embodiment of the present invention, the ratio of the radial width of the weld pattern to the length of the flat section F may be in the range of approximately 10 to 40%, preferably approximately 20 to 30%. When this ratio is in the above range, the weld strength is increased due to the increased weld area. This allows the cylindrical battery 1 according to the present invention to have high impact resistance.

[0279] In yet another aspect of the present invention, the ratio of the area of ​​the current collector 30 that is not in contact with the upper surface of the electrode assembly 10 to the area of ​​a circle having the outer diameter of the electrode assembly 10 as its diameter may be defined as the aperture ratio of the current collector 30. The aperture ratio may be calculated using Equation 8 below.

[0280] [Formula 8] Opening ratio (%) = 1 - (area where the current collector contacts the top surface of the electrode assembly) / (area of ​​a circle whose diameter is the outer diameter of the electrode assembly) = (area where the current collector does not come into contact with the top surface of the electrode assembly) / (area of ​​a circle whose diameter is the outer diameter of the electrode assembly)

[0281] The aperture ratio of the current collector 30 may be, for example, about 30% or more and less than 100%, and preferably about 60% or more and less than 100%. to 8For example, when the current collector 30 is placed on and coupled to the electrode assembly 10, the area where the current collector 30 contacts the electrode assembly 10 may be the support portion 31 and the tab coupling portion 32. In other words, the ratio of the area where the current collector 30 contacts the electrode assembly 10 to the area of ​​a circle having the outer diameter of the electrode assembly 10 as its diameter may be about 70% or less, and preferably about 40% or less. When the aperture ratio of the current collector 30 is within the above range, when an electrolyte is injected, the electrolyte can smoothly permeate into the electrode assembly 10 through the open areas of the current collector 30, including the current collector holes H2. That is, when the aperture ratio of the current collector 30 is within the above range, the electrolyte penetrates into the electrode assembly 10 through the winding hole H1 provided in the electrode assembly 10 and the open area of ​​the current collector 30. In particular, since there are minute gaps between the overlapping surfaces of the segments 11a and between adjacent segments 11a, the electrolyte can smoothly penetrate into the electrode assembly 10 by capillary action through these gaps.

[0282] 13 and 14, the distance A from the center of the current collector 30 to the end of the tab coupling portion 32 may be substantially the same as or shorter than the distance B from the center of the winding hole H1 of the electrode assembly 10 to the innermost portion of the beading portion 21 formed on the battery housing 20. In this case, interference between the beading portion 21 and the current collector 30 during the sizing process can be prevented, thereby preventing the beading portion 21 from pressing against the current collector 30 and damaging the current collector and / or the electrode assembly 10.

[0283] At least one weld bead W may be provided for each tab connection portion 32. The weld bead W may be formed not only on the tab connection portion 32 but also on the support portion 31 of the current collector 30.

[0284] As described above, the beading portion 21 may have a flat portion. At least one weld bead W may be formed between the beading portion 21 and the first contact portion 33a. The at least one weld bead W may form a linear weld pattern extending approximately in the circumferential direction on the beading portion 21. Alternatively, the at least one weld bead W formed between the beading portion 21 and the first contact portion 33a may form an arc-shaped weld pattern extending approximately in the circumferential direction on the beading portion 21. The weld bead W formed on the first contact portion 33a may have a shape extending in the circumferential direction. In another embodiment, the weld pattern may be a line shape formed by connecting spot welds. In yet another embodiment, a plurality of weld beads may be formed within the same contact portion 33a between the beading portion 21 and the first contact portion 33a.

[0285] On the other hand, when a plurality of first housing coupling portions 33 are provided, the first contact portions 33a provided in each of the plurality of first housing coupling portions 33 may be connected to each other and formed integrally, although not shown.

[0286] Referring to FIG. 1 , the housing cover 40 covers the opening formed on one side of the battery housing 20. The housing cover 40 may be fixed by a crimping portion 22 formed on the upper end of the battery housing 20. In this case, to improve fixing strength and sealing performance of the battery housing 20, a sealing gasket G1 may be interposed between the battery housing 20 and the housing cover 40 and between the current collector 30 and the housing cover 40. In this case, the first contact portion 33a and / or the second contact portion 34a may be interposed between the beading portion 21 of the battery housing 20 and the sealing gasket G1. The first contact portion 33a and / or the second contact portion 34a interposed between the beading portion 21 and the sealing gasket G1 may be fixed by bending the crimping portion 22 extending upward from the beading portion 21.

[0287] However, in the present invention, the housing cover 40 is not a component that functions as a current path, and therefore, as long as the battery housing 20 and the housing cover 40 are firmly fixed together by welding or by applying other components, and the open portion of the battery housing 20 is kept tightly sealed, the application of the sealing gasket G1 is not essential.

[0288] When the sealing gasket G1 is used, the extension length of the portion of the sealing gasket G1 interposed between the current collector 30 and the housing cover 40 may be shorter than the extension length of the portion interposed between the battery housing 20 and the housing cover 40. That is, the sealing gasket G1 may be formed so that the radial length of the portion covering the lower surface of the housing cover 40 is shorter than the radial length of the portion covering the upper surface of the housing cover 40. If the sealing gasket G1 extends too far toward the center of the cylindrical battery 1 inside the battery housing 20, the current collector 30 may be deformed due to interference between the sealing gasket G1 and the current collector 30. This may apply force to the welded portion between the current collector 30 and the battery housing 20 and / or the welded portion between the current collector 30 and the first uncoated portion 11, which may result in structural defects such as cracks. Therefore, controlling the extension length of the sealing gasket G1 as described above can prevent such defects.

[0289] 1 and 14, the sealing gasket G1 may be thicker in a region not in contact with the first contact portion 33a than in a region in contact with the first contact portion 33a. The compressibility of the sealing gasket G1 in a region in contact with the first contact portion 33a may be greater than that of a region not in contact with the first contact portion 33a. The sealing gasket G1 may have a thickness that varies from region to region along the circumferential direction on the beading portion 21 due to the presence of both a region with and a region without the first contact portion 33a. The sealing gasket G1 may have a thickness that alternates between increasing and decreasing in the circumferential direction on the beading portion 21 due to the presence of both a region with and a region without the first contact portion 33a. The sealing gasket G1 may have a compressibility that varies from region to region along the circumferential direction on the beading portion 21 due to the presence of both a region with and a region without the first contact portion 33a. This is because the degree of compression of the sealing gasket G1 differs between the area where the first contact portion 33a is inserted and the area where it is not inserted, resulting in a difference in thickness. Alternatively, by varying the thickness of the sealing gasket G1 at each position, the compression rate in the area where the sealing gasket G1 contacts the first contact portion 33a and the compression rate in the area where the sealing gasket G1 does not contact the first contact portion 33a may be substantially the same. For example, the thickness of the sealing gasket G1 that does not contact the first contact portion 33a may be increased. In this case, the compression rate of the sealing gasket G1 in the area where the first contact portion 33a is not inserted can be prevented from being relatively lower than that of the surrounding area, thereby preventing a decrease in the sealing force in that area.

[0290] Meanwhile, the housing cover 40 may include a vent 41 formed to prevent an increase in internal pressure due to gas generated inside the battery housing 20. The vent 41 is formed in a part of the housing cover 40 and is formed as a region structurally weaker than the surrounding region so that it breaks easily when pressure is applied. The vent 41 may be, for example, a region thinner than the surrounding region.

[0291] The terminal 50 penetrates the battery housing 20 from the opposite side of the open portion thereof to be electrically connected to the second uncoated portion 12 of the electrode assembly 10. The terminal 50 may penetrate approximately the center of the bottom surface of the battery housing 20. The terminal 50 may be electrically connected to the electrode assembly 10 by, for example, being coupled to a current collector (second current collector) 60 coupled to the second uncoated portion 12 or by being coupled to a lead tab (not shown) coupled to the second uncoated portion 12. Therefore, the terminal 50 has the same polarity as the second electrode of the electrode assembly 10 and can function as a second electrode terminal T2. When the second uncoated portion 12 is a positive electrode tab, the terminal 50 functions as a positive electrode terminal.

[0292] Considering the polarity and function of the terminal 50, the terminal 50 must maintain an insulated state from the battery housing 20, which has the opposite polarity. Therefore, an insulating gasket G2 may be applied between the terminal 50 and the battery housing 20. Alternatively, insulation may be achieved by coating part of the surface of the terminal 50 with an insulating material.

[0293] For the same reason, the second uncoated portion 12 and / or the current collector (second current collector) 60 must be insulated from the battery housing 20. Therefore, an insulator 70 may be interposed between the second uncoated portion 12 and the battery housing 20 and / or between the current collector (second current collector) 60 and the battery housing 20. When the insulator 70 is used, the terminal 50 may penetrate the insulator 70 to electrically connect with the second uncoated portion 12.

[0294] Meanwhile, in the present invention, the outer surface 20a of the closed portion, located opposite the open portion at the top of the battery housing 20, functions as the first electrode terminal T1. If the first uncoated portion 11 is a negative electrode tab, the first electrode terminal T1 can be the negative electrode terminal. The cylindrical battery 1 according to the present invention is structured in such a way that the terminal 50 exposed on the bottom surface opposite the open portion of the battery housing 20 is used as the second electrode terminal T2, and the remaining area of ​​the bottom surface of the battery housing 20, excluding the area occupied by the terminal 50 (including the area where the insulating gasket G2 is exposed, if the insulating gasket G2 is exposed outside the terminal 50 on the outer surface 20a of the closed portion), is used as the first electrode terminal T1. Therefore, when electrically connecting multiple cylindrical batteries 1, the cylindrical battery 1 according to the present invention can connect all the positive and negative electrodes in one direction, simplifying the electrical connection structure. Furthermore, the cylindrical battery 1 according to the present invention has a structure in which most of the bottom surface opposite the open portion of the battery housing 20 can be used as an electrode terminal, which has the advantage of ensuring sufficient area for welding components for electrical connection.

[0295] 14 together with FIG. 1, in the cylindrical battery 1 of the present invention, the current collector (first current collector) 30 is configured to be coupled to the first uncoated portion 11 and the inner surface of the battery housing 20. The current collector 30 may include a first portion that contacts the inner surface of the battery housing 20 and a second portion that is coupled to the first uncoated portion 11. In this case, when a central region of the first portion (meaning approximately the center of the electrode assembly 10 in the circumferential direction of the first portion) is projected onto a plane on which the second portion exists, the central region of the first portion and the second portion may be spaced apart in the circumferential direction of the electrode assembly 10.

[0296] A sealing gasket G1 may be interposed between the open portion of the battery housing 20 and the current collector 30, and in this case, the first portion may be interposed between the inner surface of the battery housing 20 and the sealing gasket G1. Preferably, the first portion may be interposed between the beading portion 21 of the battery housing 20 and the sealing gasket G1.

[0297] Meanwhile, the first and second portions may be located on different planes in the winding axis direction of the electrode assembly 10. That is, the first and second portions may be located spaced apart from each other along the height direction (Z-axis direction) of the cylindrical battery 1.

[0298] Referring to FIG. 25 together with FIG. 1, the current collector (second current collector) 60 is coupled to the lower part of the electrode assembly 10. The current collector 60 is made of a conductive metal material and is electrically connected to the second uncoated portion 12. The current collector 60 may be coupled to a coupling surface (folded surface) 102 (see FIG. 15) formed by bending an end of the second uncoated portion 12 in a direction parallel to the current collector 60. The bending direction of the second uncoated portion 12 may be a radial direction, for example, toward the core of the electrode assembly 10. When the second uncoated portion 12 has such a folded shape, the space occupied by the second uncoated portion 12 in the vertical direction is reduced, thereby improving energy density. Furthermore, when the current collector 60 is coupled to the coupling surface 102 formed by bending the second uncoated portion 12, the increased coupling area can improve coupling strength and reduce contact resistance. This is also true for the first uncoated portion 11 described above.

[0299] The current collector (second current collector) 60 includes a tab coupling portion (second tab coupling portion) 62 and a terminal coupling portion 63. The current collector 60 may further include a peripheral portion 61. The peripheral portion 61 is disposed at the bottom of the electrode assembly 10 and may have a substantially rim shape with an empty space S formed therein. Although the drawings only show the peripheral portion 61 in a substantially circular rim shape, the present invention is not limited thereto. Unlike the illustrations, the peripheral portion 61 may have a substantially square rim shape, a hexagonal rim shape, an octagonal rim shape, or other rim shapes.

[0300] The tab coupling portion 62 extends inward from the peripheral portion 61 and is coupled to the second uncoated portion 12. As described above, the current collector 60 and the second uncoated portion 12 are preferably coupled to each other so that they overlap by at least about 50% with the uniform stacking region where the number of overlapping layers of the divided pieces is approximately constant and at approximately the maximum value. That is, the tab coupling portion 62 of the current collector 60 may be coupled to the second uncoated portion 12 so that it overlaps by at least about 50% with the uniform stacking region.

[0301] The terminal coupling portion 63 is spaced apart from the tab coupling portion 62. The terminal coupling portion 63 may be located inside the peripheral portion 61. The terminal coupling portion 63 may be coupled to the terminal 50, which will be described later, by welding. The terminal coupling portion 63 may have a diameter that is substantially the same as or larger than the diameter of the flat portion formed on the bottom surface of the terminal 50 to ensure a welding area for coupling with the flat portion formed on the bottom surface of the terminal 50. The terminal coupling portion 63 may be located, for example, approximately at the center of the inner space surrounded by the peripheral portion 61.

[0302] The terminal coupling portion 63 may be disposed at a position corresponding to the winding hole H1 formed in the core portion of the electrode assembly 10. The terminal coupling portion 63 may cover the winding hole H1 of the electrode assembly 10 so that the winding hole H1 of the electrode assembly 10 is not exposed to the outside. When the winding hole H1 of the electrode assembly 10 is covered in this manner, it is possible to prevent the separator located inside the hole from being damaged due to the flow rate of the electrolyte passing through the hole, thereby preventing the electrode from being exposed. Therefore, the terminal coupling portion 63 may have a diameter or width larger than the winding hole H1, as described above. However, the present invention does not exclude the case where the diameter of the terminal coupling portion 63 is smaller than the diameter of the flat portion formed on the bottom surface of the terminal 50.

[0303] The tab coupling portion 62 and the terminal coupling portion 63 are not directly connected but are spaced apart and electrically connected by the peripheral portion 61. In this way, the current collector 60 of the present invention has a structure in which the tab coupling portion 62 and the terminal coupling portion 63 are not directly connected but are indirectly connected through the peripheral portion 61. This allows the current collector 60 to disperse impacts applied to the coupling portion between the tab coupling portion 62 and the second uncoated portion 12 and the coupling portion between the terminal coupling portion 63 and the terminal 50 when the cylindrical battery 1 is subjected to impact and / or vibration. Therefore, the current collector 60 of the present invention can minimize or prevent damage to welded portions due to external impact. More specifically, the current collector 60 of the present invention has a structure in which stress is concentrated at the coupling portion between the peripheral portion 61 and the terminal coupling portion 63 when an external impact is transmitted to the inside of the cylindrical battery 1 through the terminal 50. However, this coupling portion is not a portion where a weld is formed to connect the components. Therefore, the present invention can effectively prevent product defects caused by damage to welded portions due to external impact.

[0304] The outer diameter of the current collector (second current collector) 60 may be longer than the outer diameter of the current collector (first current collector) 30. The outer diameter of the second current collector 60 refers to a length that is twice the distance from the center of the second current collector 60 to the end of the second tab coupling portion 62 (or the distance to the peripheral portion 61 if the second current collector 60 has the peripheral portion 61). The outer diameter of the first current collector 30 refers to a length that is twice the distance from the center of the first current collector 30 to the outermost portion of the first tab coupling portion 32. The second current collector 60 may have an outer diameter that is close to the inner diameter of the battery housing 20. The second current collector 60 may have an outer diameter that is approximately 33% to 98.5% of the inner diameter of the battery housing 20. The minimum outer diameter of the second current collector 60 is a value that prevents an excessive increase in resistance. The maximum outer diameter of the second current collector 60 takes into consideration factors such as the tolerance of the outer diameter of the second current collector 60 that may occur during manufacturing of the current collector 60, the assembly tolerance that may occur during the combination of the electrode assembly 10 and the second current collector 60, the tolerance of the inner diameter of the battery housing 20 that may occur during manufacturing of the battery housing 20, and the positional tolerance that may occur when the combination of the electrode assembly 10 and the second current collector 60 is inserted into the battery housing 20. In the present invention, when an insulator 70 is used and has a structure in which the insulator 70 covers the outer periphery of the electrode assembly 10 up to the upper end thereof, the insertion space of the insulator 70 must also be taken into consideration, so the ratio of the outer diameter of the second current collector 60 to the inner diameter of the battery housing 20 becomes smaller than the above maximum value. The outer diameter of the second current collector 60 is limited to a level that is slightly smaller than the inner diameter of the battery housing 20 in consideration of these tolerances, while the diameter of the first current collector 30 may be further limited to avoid interference that may occur during a sizing process. To avoid such interference, the outer diameter of the first current collector 30 may be formed to be approximately the same as or smaller than the inner diameter of the battery housing 20 in the region where the beading portion 21 is formed.

[0305] Meanwhile, when the outer diameter of the first current collector 30 and / or the second current collector 60 is T, the outer diameter of the electrode assembly 10 is JR, and the height of the outermost portion of the first uncoated portion 11 and / or the second uncoated portion 12 is F, the following Equation 9 may be satisfied. Here, the outer diameter of the first current collector 30 means twice the distance from the center of the first current collector 30 to the end of the first tab coupling portion 32, and the outer diameter of the second current collector 60 means twice the distance from the center of the second current collector 60 to the end of the second tab coupling portion 62 (or the outermost portion of the peripheral portion 61).

[0306] [Formula 9] JR-2×F≦T <JR

[0307] Preferably, the outer diameter T of the first current collector 30 and / or the second current collector 60 may be equal to or greater than the outer diameter JR of the electrode assembly 10 minus twice the height F of the outermost segment 11a of the first uncoated portion 11 and / or the second uncoated portion 12. When this relationship is satisfied, the first tab coupling portion 32 and / or the second tab coupling portion 62 covers the end of the outermost segment 11a. That is, the first current collector 30 and / or the second current collector 60 may have an outer diameter that covers the end of the segment bent at the last winding turn of the first electrode. In this case, the entire segment 11a forming the bent surface 102 to which the first tab coupling portion 32 and / or the second tab coupling portion 62 (or the peripheral portion 61) is joined can be welded while being uniformly pressed by the current collector 30, and the segment segments 11a can be maintained in a tightly stacked state even after welding. The tightly stacked state is shown in Figure 30 This means that there are substantially no gaps between the segments, as shown in Fig. 1. The tightly stacked state contributes to reducing the resistance of the cylindrical battery 1 to a level suitable for fast charging (for example, 4 mΩ) or less.

[0308] In another embodiment, the outer diameter T of the first current collector 30 and / or the second current collector 60 may be smaller than the outer diameter JR of the electrode assembly 10. If the outer diameter T of the first current collector 30 and / or the second current collector 60 is larger than the outer diameter JR of the electrode assembly 10, dead space inside the battery housing 20 may increase, adversely affecting the energy density of the cylindrical battery 1. Therefore, it is preferable that the outer diameter T of the first current collector 30 and / or the second current collector 60 be smaller than the outer diameter JR of the electrode assembly 10.

[0309] Meanwhile, the length L2 of the weld connecting the second tab coupling portion 62 of the second current collector 60 and the second uncoated portion 12 along the radial direction of the electrode assembly 10 may be longer than the length L1 of the weld connecting the first tab coupling portion 32 of the first current collector 30 and the first uncoated portion 11 along the radial direction of the electrode assembly 10. For example, if the second current collector 60 is a positive current collector made of aluminum and the first current collector 30 is a negative current collector made of copper, forming the length L2 longer than the length L1 allows the area of ​​the weld of the positive current collector, which has a relatively lower electrical conductivity, to be larger, thereby balancing the current flow between the positive current collector and the negative current collector. Here, the extension length of the weld connecting the current collectors 30, 60 and the uncoated portions 11, 12 refers to the length of the weld bead formed by welding.

[0310] The distance from the core of the electrode assembly 10 to a start point of a weld that joins the first tab connecting portion 32 of the first current collector 30 to the first uncoated portion 11 may be substantially the same as the distance to a start point of a weld that joins the second tab connecting portion 62 of the second current collector 60 to the second uncoated portion 12. Here, "substantially the same" may mean that the two distances are the same or have a deviation of, for example, about 5% or less.

[0311] The current collector 60 may further include a bridge portion 64 extending inward from the peripheral portion 61 and connected to the terminal coupling portion 63. The bridge portion 64 may have a tapered portion 64a whose width narrows continuously and / or stepwise from the inner surface of the peripheral portion 61 toward the terminal coupling portion 63. The tapered portion 64a may have a shape in which its width widens continuously and / or stepwise toward the peripheral portion 61 at the connection portion between the terminal coupling portion 63 and the peripheral portion 61. When the tapered portion 64a is provided, the rigidity of the part at the connection portion between the bridge portion 64 and the peripheral portion 61 is improved. When the tapered portion 64a is provided, during the manufacturing process of the cylindrical battery 1, for example, a transfer device and / or a worker can grasp the tapered portion 64a to easily and safely transfer the current collector 60 and / or the combination of the current collector 60 and the electrode assembly 10. That is, when the tapered portion 64a is provided, defects in the product caused by gripping a part to be welded to another part, such as the tab connecting portion 62 or the terminal connecting portion 63, can be prevented.

[0312] There may be a plurality of tab connecting portions 62 and / or bridge portions 64. The number of tab connecting portions 62 and / or bridge portions 64 may be determined in consideration of the resistance level required for the cylindrical battery 1, the aperture ratio required for the current collector 60, etc.

[0313] 1 and 26, the bridge portion 64 may include a current-blocking portion N formed to partially reduce the cross-sectional area of ​​the bridge portion 64. The reduction in the cross-sectional area of ​​the bridge portion 64 in the region where the current-blocking portion N is formed may be implemented, for example, by partially reducing the width and / or thickness. When the current-blocking portion N is provided, electrical resistance in the region where the current-blocking portion N is formed increases, thereby causing the current-blocking portion N to break when an overcurrent occurs, enabling rapid current interruption. A plurality of current-blocking portions N may be provided along the longitudinal direction of the bridge portion 64. When a plurality of bridge portions 64 are provided, a current-blocking portion may be provided in at least one of the bridge portions 64. While the drawings only show the case where the current-blocking portion N is in the form of a notch, this is not intended to limit the present invention and may include, for example, a groove and / or a through-hole. Meanwhile, although not shown, a tape covering the bridge portion 64 may be applied to the region where the current-blocking portion N is formed. When the tape is applied, foreign matter such as molten metal generated when the current interrupting part N breaks can be prevented from scattering onto other components and causing a short circuit, etc. In addition, since the heat generated in the current interrupting part N is not transferred to the outside, the current interrupting part N can break more quickly.

[0314] Meanwhile, the current interrupting portion N is preferably provided in a region corresponding to the uniform lamination section of the second uncoated portion 12 to prevent foreign matter generated during breakage from entering the electrode assembly 10. This is because the number of overlapping layers of the second uncoated portion 12 segments is maximized in this region, allowing the overlapping segments to function as a mask. The current interrupting portion N may be formed, for example, at a point radially away from the core of the electrode assembly 10, approximately 40% to 90% of the radius of the electrode assembly 10. Preferably, the current interrupting portion N may be located approximately in the center between the core and outermost portions of the electrode assembly 10.

[0315] 27 to 30, the structure of the electrode assembly 10 will be described in more detail. In the following description, the first electrode of the first and second electrodes described above will be described as an example, but the structure of the first electrode can be similarly applied to the second electrode.

[0316] 27 to 30, the first electrode 110 includes a sheet-shaped first electrode collector 111 made of a foil of a conductive material, a first active material layer 112 formed on at least one surface of the first electrode collector 111, and a first uncoated portion 11 on the long side end of the first electrode collector 111 where no active material is coated.

[0317] Preferably, the first uncoated portion 11 may include a plurality of notched segments 11a. The segments 11a may be arranged in a plurality of groups, and the segments 11a in each group may have substantially the same height (length in the Z direction), width (length in the X direction), and / or spacing pitch. The number of segments 11a in each group may be greater or less than that shown in the figure. The segments 11a have a geometric shape formed by combining at least one straight line and / or at least one curved line. Preferably, the segments 11a may be trapezoidal, but may also be modified into a rectangle, parallelogram, semicircle, semi-ellipse, or the like.

[0318] Preferably, the height of the segment 11a increases stepwise, for example, from the core side to the outer periphery, along a direction parallel to the winding direction of the electrode assembly 10. Furthermore, the core-side uncoated region 11-1 adjacent to the core side of the electrode assembly 10 may not include a segment 11a, and the height of the core-side uncoated region 11-1 may be lower than the height of the uncoated regions in other regions. Furthermore, the outer periphery uncoated region 11-2 adjacent to the outer periphery of the electrode assembly 10 may not include a segment 11a, and the height of the outer periphery uncoated region 11-2 may be lower than the height of the other uncoated regions.

[0319] Optionally, the first electrode 110 may include an insulating coating layer E covering the boundary between the first active material layer 112 and the first uncoated portion 11. The insulating coating layer E includes an insulating polymer resin and may optionally further include an inorganic filler. The insulating coating layer E prevents the end of the first active material layer 112 from contacting the active material layer of the opposite polarity facing the separator and serves to structurally support the folding of the divided piece 11a. Therefore, when the first electrode 110 is wound to form the electrode assembly 10, it is preferable that at least a portion of the insulating coating layer E is exposed to the outside through the separator.

[0320] 27 and 28, the electrode assembly 10 can be manufactured using the winding method described with reference to Fig. 2. For ease of explanation, the protruding structures of the uncoated portions 11 and 12 extending outward from the separator are shown in detail, and the winding structures of the first electrode, second electrode, and separator are not shown. The first uncoated portion 11 protruding upward is extended from the first electrode, and the second uncoated portion 12 protruding downward is extended from the second electrode.

[0321] The varying heights of the uncoated portions 11 and 12 are shown only schematically. That is, the heights of the uncoated portions 11 and 12 may vary irregularly depending on the cutting position of the cross section. For example, if the side portions of the trapezoidal segment 11a are cut, the height of the uncoated portions in the cross section will be lower than the height of the segment 11a. Therefore, it should be understood that the heights of the uncoated portions 11 and 12 shown in the cross-sectional views of the electrode assembly 10 correspond to the average height of the uncoated portions included in each winding turn.

[0322] 27 to 30, the uncoated portions 11 and 12 can be folded radially from the outer periphery toward the core of the electrode assembly 10. The bending locations of the uncoated portions 11 and 12 are indicated by dotted boxes in FIG. 28. When the uncoated portions 11 and 12 are folded, adjacent segments overlap each other in the radial direction, forming folded surfaces 102 at the top and bottom of the electrode assembly 10. The core-side uncoated portion (11-1 in FIG. 27) is too low to be folded. The height h of the innermost folded segment 11a is approximately equal to or less than the sum of the radial length r of the winding region formed by the core-side uncoated portion 11-1 without a segment structure and 10% of the diameter of the winding hole. Therefore, the holes formed in the core C of the electrode assembly 10 are not blocked. If the holes are not blocked, the electrolyte injection process is unaffected and the efficiency of the electrolyte injection is improved. Also, a welding tool can be inserted through the hole to easily weld the terminal 50 and the second current collector 60 together (see FIG. 13).

[0323] 31, a plurality of cylindrical batteries 1 can be connected in series and parallel at the top of the cylindrical batteries 1 using bus bars 150. The number of cylindrical batteries 1 can be increased or decreased depending on the capacity of the battery pack.

[0324] In each cylindrical battery 1, for example, the terminal 50 may have a positive polarity, and the outer surface 20a of the closed portion of the battery housing 20 may have a negative polarity. Of course, the opposite is also possible. The terminal 50 of the cylindrical battery 1 and the outer surface 20a of the closed portion located opposite the opening of the battery housing 20 may all be oriented upward (upside down, as opposed to the configuration shown in FIG. 1).

[0325] Preferably, a plurality of cylindrical batteries 1 may be arranged in a plurality of columns and rows. The columns are vertically aligned relative to the ground, and the rows are horizontally aligned relative to the ground. Furthermore, to maximize space efficiency, the cylindrical batteries 1 may be arranged in the closest packing structure. This closest packing structure is formed when an equilateral triangle is drawn when the centers of the exposed terminal portions of the terminals 50 exposed to the outside of the battery housing 20 are connected to each other. Preferably, a bus bar 150 may be arranged on top of the plurality of cylindrical batteries 1, more preferably between adjacent columns. Alternatively, the bus bar 150 may be arranged between adjacent rows.

[0326] Preferably, the bus bars 150 connect cylindrical batteries 1 arranged in the same row in parallel to each other, and connect cylindrical batteries 1 arranged in two adjacent rows in series to each other.

[0327] Preferably, bus bar 150 may include a body portion 151, a plurality of first bus bar terminals 152, and a plurality of second bus bar terminals 153 for series and parallel connection.

[0328] The body portion 151 may extend between the terminals 50 of adjacent cylindrical batteries 1, preferably between rows of cylindrical batteries 1. Alternatively, the body portion 151 may extend along the row of cylindrical batteries 1, but may be folded regularly, such as in a zigzag pattern.

[0329] The multiple first bus bar terminals 152 may protrude from one side of the body portion 151 toward the terminals 50 of each cylindrical battery 1 and be electrically coupled to the terminals 50. The electrical coupling between the first bus bar terminals 152 and the terminals 50 may be performed by laser welding, ultrasonic welding, etc. Furthermore, the multiple second bus bar terminals 153 may be electrically coupled to the outer surface 20a of each cylindrical battery 1 from the other side of the body portion 151. The electrical coupling between the second bus bar terminals 153 and the outer surface 20a may be performed by laser welding, ultrasonic welding, etc.

[0330] Preferably, the body portion 151, the plurality of first bus bar terminals 152, and the plurality of second bus bar terminals 153 may be formed from a single conductive metal plate. The metal plate may be, for example, an aluminum plate or a copper plate, but the present invention is not limited thereto. Alternatively, the body portion 151, the plurality of first bus bar terminals 152, and the second bus bar terminals 153 may be manufactured as separate pieces and then joined together by welding or the like.

[0331] In the cylindrical battery 1 according to the present invention, the terminal 50 having the positive polarity and the outer surface 20a of the closed portion of the battery housing 20 having the negative polarity are positioned in the same direction, so electrical connection between cylindrical batteries 1 can be easily achieved using the bus bar 150.

[0332] In addition, the terminals 50 of the cylindrical batteries 1 and the outer surface 20a of the closed portion of the battery housing 20 have a large area, so the connection area of ​​the busbars 150 is sufficient, and the resistance of the battery pack including the cylindrical batteries 1 can be sufficiently reduced.

[0333] Desirably, the cylindrical battery may be, for example, a cylindrical battery having a form factor ratio (defined as the diameter of a cylindrical battery divided by its height, i.e., the ratio of height (H) to diameter (Φ)) greater than about 0.4.

[0334] Here, form factor refers to a value indicating the diameter and height of a cylindrical battery. Cylindrical batteries according to an embodiment of the present invention may be, for example, 46110 batteries, 4875 batteries, 48110 batteries, 4880 batteries, or 4680 batteries. In the form factor number, the first two digits indicate the diameter of the battery, and the following digits indicate the height of the battery.

[0335] A cylindrical battery according to one embodiment of the present invention may be a cylindrical battery having a substantially cylindrical shape with a diameter of about 46 mm, a height of about 110 mm, and a form factor ratio of about 0.418.

[0336] A cylindrical battery according to another embodiment may be a cylindrical battery having a generally cylindrical shape with a diameter of about 48 mm, a height of about 75 mm, and a form factor ratio of about 0.640.

[0337] A cylindrical battery according to yet another embodiment may be a generally cylindrical battery having a diameter of about 48 mm, a height of about 110 mm, and a form factor ratio of about 0.436.

[0338] A cylindrical battery according to yet another embodiment may be a cylindrical battery having a generally cylindrical shape with a diameter of about 48 mm, a height of about 80 mm, and a form factor ratio of about 0.600.

[0339] A cylindrical battery according to yet another embodiment may be a cylindrical battery having a generally cylindrical shape with a diameter of about 46 mm, a height of about 80 mm, and a form factor ratio of about 0.575.

[0340] Conventionally, batteries with a form factor ratio of approximately 0.4 or less have been used. For example, 1865 batteries and 2170 batteries have been used. 1865 batteries have a diameter of approximately 18 mm, a height of approximately 65 mm, and a form factor ratio of approximately 0.277. 2170 batteries have a diameter of approximately 21 mm, a height of approximately 70 mm, and a form factor ratio of approximately 0.300.

[0341] As described above, the cylindrical battery 1 of the present invention has a structure that minimizes resistance by increasing the contact area between components, multiple current paths, and minimizing the length of the current paths. After the product is completed, the AC resistance of the cylindrical battery 1 measured with a resistance meter between the positive and negative electrodes, i.e., between the top surface of the terminal 40 and the outer surface 20a of the closed portion of the battery housing 20, may be approximately 4 mΩ or less. The AC resistance of the cylindrical battery 1 may be approximately 0.5 mΩ or more, preferably approximately 1.0 mΩ or more.

[0342] 32, a battery pack 3 according to one embodiment of the present invention includes a battery assembly in which a plurality of cylindrical batteries 1 according to one embodiment of the present invention are electrically connected, and a pack housing 2 that accommodates the battery assembly. For ease of illustration, components such as bus bars for electrical connection, a cooling unit, and power terminals are not shown. The electrical connection structure of a plurality of cylindrical batteries 1 for manufacturing the battery pack 3 is as exemplarily described above with reference to FIG. 31.

[0343] 33, an automobile 5 according to an embodiment of the present invention may be, for example, an electric automobile, a hybrid automobile, or a plug-in hybrid automobile, and includes a battery pack 3 according to an embodiment of the present invention. The automobile 5 includes a four-wheeled automobile and a two-wheeled automobile. The automobile 5 operates by receiving a supply of power from the battery pack 3 according to an embodiment of the present invention.

[0344] According to the present invention, the resistance in the electrical connection between the electrode assembly and the battery housing can be significantly reduced. In another aspect, according to the present invention, the bonding strength of the bonding portion between the current collector and the battery housing can be improved. In yet another aspect, according to the present invention, the energy density of a cylindrical battery can be improved. In yet another aspect, according to the present invention, the productivity can be improved by increasing the convenience of the welding process for electrically connecting the battery housing and the current collector in the manufacture of a cylindrical battery. In yet another aspect, according to the present invention, the possibility of damage occurring in the welded portion between the current collector and the electrode assembly and / or the welded portion between the current collector and the battery housing even when vibrations and impacts are applied during the use of the battery can be significantly reduced. Furthermore, according to the present invention, the productivity can be improved by increasing the convenience of the welding process for electrically connecting the battery housing and the current collector in the manufacture of a cylindrical battery.

[0345] As described above, the present invention has been described using limited embodiments and drawings, but the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims.

Claims

1. An electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding shaft to define a core and an outer circumferential surface, the first electrode including a first uncoated portion in which an active material layer is not coated along the winding direction; a battery housing having an opening on one side thereof and accommodating the electrode assembly through the opening; a first current collector including a support portion disposed on an upper portion of the electrode assembly, a first tab coupling portion extending from the support portion and coupled to the first uncoated portion, and a first housing coupling portion extending from the support portion and electrically coupled to an inner surface of the battery housing; a housing cover that seals the opening; Including, the battery housing has a beading portion formed at an end adjacent to the opening and pressed inward; The battery, wherein the first housing coupling portion is coupled onto the beading portion of the battery housing.

2. The battery according to claim 1 , wherein the first tab connecting portion and the first housing connecting portion are not directly connected to each other but are indirectly connected to each other through the support portion.

3. The battery according to claim 1 or 2, wherein the first tab coupling portion has at least one liquid filling hole.

4. An electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding shaft to define a core and an outer circumferential surface, the first electrode including a first uncoated portion in which an active material layer is not coated along the winding direction; a battery housing having an opening on one side thereof and accommodating the electrode assembly through the opening; a first current collector including a support portion disposed on an upper portion of the electrode assembly, a first tab coupling portion extending from the support portion and coupled to the first uncoated portion, and a first housing coupling portion extending from the support portion and electrically coupled to an inner surface of the battery housing; a housing cover that seals the opening; Including, the battery housing has a beading portion formed at an end adjacent to the opening and pressed inward; The first housing coupling portion is a first contact portion coupled onto the beading portion of the battery housing; a first connecting portion connecting the support portion and the first contact portion; Including batteries.

5. The battery according to claim 4 , wherein the first connecting portion is disposed so that at least a portion of the first connecting portion is in contact with the first uncoated portion.

6. The battery according to claim 4 or 5, wherein the first connecting portion and the first contact portion have the same width along the extension direction.

7. The battery of claim 4 , wherein the first tab bond portion has a width greater than the first connecting portion.

8. The battery according to claim 4 or 5, wherein the first contact portion has a width greater than that of the first connecting portion.

9. The battery according to claim 4 , wherein the first connecting portion has a structure that is convex upward with respect to an imaginary straight line that connects both ends of the first connecting portion in the longitudinal direction.

10. The battery according to claim 4 , wherein the first connecting portion has a structure elevated above the beading portion.

11. The beading portion is an upper beading portion located above the innermost pressed point; a lower beading portion located below the innermost pressed point; 11. The battery of claim 4, comprising:

12. The battery according to claim 11 , wherein the upper beading portion and the lower beading portion are asymmetrical with respect to an imaginary reference plane that passes through the innermost points of the beading portions parallel to the bottom surface of the battery housing.

13. The battery according to claim 11 or 12, wherein the first tab connection portion of at least one of the first current collectors is located below the lower beading portion.

14. The battery according to claim 11 , wherein at least one of the upper beading portion and the lower beading portion is inclined at a predetermined angle with respect to the lower surface of the battery housing.

15. The battery of claim 14 , wherein the first contact portion rests on an inclined upper surface of the beading portion.

16. The battery according to claim 11 or 12, wherein at least one of the upper beading portion and the lower beading portion is parallel to the lower surface of the battery housing in at least a portion thereof.

17. 17. The battery of claim 16, wherein the first contact portion rests on a flat upper surface of the beading portion.

18. 18. The battery of claim 11, wherein the first contact portion is welded to an upper surface of the beading portion.

19. 19. The battery of claim 11, wherein the first contact is welded into a flat area formed on the upper beading portion.

20. The battery according to claim 4 , wherein the first contact portion has an arc shape with at least a portion extending circumferentially along the beading portion of the battery housing.

21. 20. The battery of claim 4, wherein the first contact portion has an arc shape extending in opposite directions along a circumferential direction on the beading portion from an intersection point between the first connecting portion and the first contact portion.

22. The indentation depth of the beading portion is defined as PD, The minimum value of the curvature radius of the beading portion is R1, ｍｉｎ year, The minimum weld bead width is W ｂｅａｄ，ｍｉｎ year, The minimum radius of curvature in the boundary region between the beading portion and the inner surface of the battery housing is R2, ｍｉｎ Then, the following formula 1 [Formula 1] PD≧R1, ｍｉｎ +R2, ｍｉｎ +W ｂｅａｄ，ｍｉｎ The battery of claim 1 , wherein

23. 2. The battery according to claim 1, wherein the beading portion has a pressing depth of 0.2 mm to 10 mm.

24. The indentation depth of the beading portion is defined as PD, and the maximum value of the indentation depth is defined as PD ｍａｘ year, an overlap length that is the shortest distance from an end of the first contact portion to a vertical line passing through the innermost point of the beading portion is defined as OV; The minimum value of the curvature radius of the beading portion is R1, ｍｉｎ year, The minimum weld bead width is W ｂｅａｄ，ｍｉｎ year, The minimum radius of curvature in the boundary region between the beading portion and the inner surface of the battery housing is R2, ｍｉｎ Then, the following formula 2 [Formula 2] (R1, ｍｉｎ +W ｂｅａｄ，ｍｉｎ ) / PD ｍａｘ ≦OV / PD≦(PD ｍａｘ -R2, ｍｉｎ ) / PD ｍａｘ 22. The battery according to claim 4, wherein

25. The battery according to claim 18 , wherein a welding area between the first contact portion and the beading portion is formed narrower than a flat upper surface of the beading portion.

26. The indentation depth of the beading portion is defined as PD, and the maximum value of the indentation depth is defined as PD ｍａｘ year, The distance from the innermost point of the beading portion to the center point of the weld bead located at the outermost edge in the radial direction is defined as W, The overlap length, which is the shortest distance from the end of the first contact portion to a vertical line passing through the innermost point of the beading portion, is defined as OV, and the minimum value of OV is defined as OV. ｍｉｎ The maximum value of OV is OV ｍａｘ year, The minimum weld bead width is W ｂｅａｄ，ｍｉｎ Then, the following equation 3 [Formula 3] (OV ｍｉｎ -0.5×W ｂｅａｄ，ｍｉｎ ) / PD ｍａｘ ≦W / PD≦(OV ｍａｘ -0.5×W ｂｅａｄ，ｍｉｎ ) / PD ｍａｘ 22. The battery according to claim 4, wherein

27. The minimum distance from the innermost point of the beading portion to the center point of the weld bead located at the outermost edge in the radial direction is defined as W1, When the overlap length is OV, the distance from the innermost point of the beading portion to the center point of the weld bead located at the outermost edge in the radial direction is W, and the following equation 4 is used: [Formula 4] W1=R1+0.5×W ｂｅａｄ，ｍｉｎ W=OV-0.5×W ｂｅａｄ，ｍｉｎ 27. The battery of claim 26, wherein

28. the beading portion has a flat section parallel to the lower surface of the battery housing in at least a partial area; The length of the flat section of the beading portion that contacts the first current collector is 28. The battery according to claim 26 or 27, wherein when the overlap length is OV and the radius of curvature of the beading portion is R1, the battery has a relationship of OV-R1.

29. The radial width of the weld pattern formed between the beading portion and the first contact portion is W ｂｅａｄ，ｍｉｎ The battery according to claim 28, wherein the resistance is OV-R1 or more.

30. 30. The battery of claim 29, wherein the ratio of the radial width of the weld pattern to the length of the flat section satisfies a range of 10 to 40%.

31. The battery of claim 4 , wherein the first connecting portion includes at least one first bent portion whose extension direction is changed at least once.

32. 32. The battery of claim 31, wherein the first bent portion is located above an imaginary plane that passes through the center of an imaginary line connecting one end of the first contact portion and one end of the first tab connection portion and is parallel to the bottom surface of the battery housing.

33. 33. The battery of claim 31 or 32, wherein the at least one first bent portion is bent at an obtuse angle so as not to overlap each other when viewed from the longitudinal axis of the battery housing.

34. The battery according to claim 31 , wherein a boundary between the first contact portion and the first connecting portion is bent at an obtuse angle.

35. The battery of claim 33 or 34, wherein the first connecting portion has a shape in which the inclination thereof decreases stepwise or gradually toward the beading portion.

36. 22. The battery according to claim 4, wherein an angle formed between the first tab coupling portion and the first connecting portion is between 0° and 90°.

37. The battery of claim 4 , wherein the first connector supports the housing cover.

38. 22. The battery of claim 4, wherein the first tab bond portion and the first contact portion are located at substantially the same height.

39. The battery of claim 4 , wherein the first contact portion has a flat surface that is coupled with an upper surface of the beading portion that faces the opening.

40. 40. The battery of claim 1, wherein the first current collector includes a current collector hole formed in a center thereof.

41. The battery according to claim 40 , wherein the current collector holes are provided at positions corresponding to winding holes formed in the center of the electrode assembly.

42. 42. The battery of claim 41, wherein the diameter of the current collector holes is greater than or equal to the diameter of the winding holes provided in the core of the electrode assembly.

43. 43. The battery of claim 1, wherein the first current collector further includes a second housing connection portion extending from an end of the first tab connection portion and connected to an inner surface of the battery housing.

44. The second housing coupling portion is a second contact portion coupled to an inner surface of the battery housing; a second connecting portion connecting an end of the first tab connecting portion and the second contact portion; 44. The battery of claim 43, comprising:

45. The second connecting portion is 45. The battery of claim 44, wherein at least a portion of the battery is positioned in contact with the first uncoated portion.

46. 46. ​​The battery of claim 44 or 45, wherein the first tab coupling portion, the second connecting portion, and the second contact portion have the same width along the extension direction.

47. 47. The battery of any one of claims 44 to 46, wherein the first tab bond portion has a width greater than the second connection portion.

48. 48. The battery of any one of claims 44 to 47, wherein the second contact portion has a width greater than the second connecting portion.

49. 49. The battery according to claim 44, wherein at least a portion of the second contact portion extends along an inner circumferential surface of the battery housing.

50. The second connecting portion is 50. The battery of any one of claims 44 to 49, comprising at least one second bent portion where the extension direction is reversed at least once.

51. 2. The battery according to claim 1, wherein a distance from a center of the first current collector to an end of the first tab connection portion is substantially equal to or shorter than a distance from a center of a winding hole of the electrode assembly to an innermost portion of the beading portion.

52. The battery according to claim 1 , wherein the beading portion has a flat portion on an upper surface thereof.

53. At least one weld bead is formed between the beading portion and the first contact portion, 22. The battery of claim 19, wherein at least one of the weld beads forms a linear weld pattern extending along a circumferential direction.

54. At least one weld bead is formed between the beading portion and the first contact portion, 22. The battery of claim 19, wherein at least one of the weld beads forms an arc-shaped weld pattern extending along a circumferential direction.

55. a weld bead formed between the beading portion and the first contact portion to form a weld pattern; 22. The battery of claim 19, wherein the welding pattern is a line of connected spot welds.

56. The battery according to claim 4 , wherein a plurality of weld beads are formed between the beading portion and the first contact portion within the same first contact portion.

57. the second electrode further includes a second uncoated portion that is not coated with an active material layer along the winding direction, 57. The battery of claim 1, further comprising a terminal that penetrates the battery housing from the opposite side of the open portion and is electrically connected to the second uncoated portion.

58. a second current collector positioned between the electrode assembly and the terminal; The second current collector is a second tab coupling portion coupled to the second plain portion; a terminal coupling portion coupled to the terminal; 58. The battery of claim 57, comprising:

59. 59. The battery of claim 58, wherein the terminal coupling portion covers a winding hole of the electrode assembly.

60. 60. The battery of claim 58 or 59, wherein the outer diameter of the second current collector is greater than the outer diameter of the first current collector.

61. 61. The battery of any one of claims 58 to 60, wherein the second tab bonding portion is bonded onto a bonding surface formed by folding the second plain portion.

62. The battery housing comprises:

22. The battery according to claim 4, further comprising a crimping portion formed on top of the beading portion, the crimping portion being extended and bent to wrap around the peripheral edge of the housing cover.

63. 63. The battery of claim 62, wherein the first housing coupling portion is crimped and secured by the crimping portion.

64. 64. The battery of claim 62 or 63, wherein the battery further includes a sealing gasket disposed within the crimping portion and interposed between the battery housing and the housing cover.

65. 65. The battery of claim 64, wherein the first contact portion is interposed between the beading portion and the sealing gasket.

66. 66. The battery of claim 65, wherein the first contact portion is secured by bending the crimping portion.

67. The sealing gasket is 67. The battery of any one of claims 64 to 66, wherein the battery is thicker in areas not in contact with the first contact than in areas in contact with the first contact.

68. The sealing gasket is 68. The battery of any one of claims 64 to 67, wherein the compressibility in the area in contact with the first contact is greater than the compressibility in the area not in contact with the first contact.

69. The sealing gasket is 69. The battery of any one of claims 64 to 68, wherein the compressibility in the area in contact with the first contact is substantially the same as the compressibility in the area not in contact with the first contact.

70. 70. The battery of any one of claims 64 to 69, wherein the sealing gasket has a thickness that varies from region to region around the circumference of the beading portion.

71. 71. The battery of any one of claims 64 to 70, wherein the sealing gasket has an alternating increase and decrease in thickness along the circumferential direction on the beading portion.

72. 72. The battery of any one of claims 64 to 71, wherein the sealing gasket has a compressibility that varies from region to region along the circumferential direction on the beading portion.

73. 2. The battery of claim 1, wherein the first housing coupling portion is resiliently biased onto the beading portion.

74. 40. The battery according to claim 30, wherein a connection portion between the first contact portion and the first connecting portion is aligned with an inner surface of the beading portion.

75. At least a portion of the first uncoated portion includes a plurality of segments separated along the winding direction of the electrode assembly, 75. The battery of claim 1, wherein the plurality of segments are folded along the radial direction of the electrode assembly to form a folded surface.

76. The folded pieces are It forms a curved surface by overlapping multiple layers.

76. The battery of claim 75, wherein the curved surface includes an increasing lamination number section in which the number of overlapping layers of the segment gradually increases from the outer periphery side of the electrode assembly toward the core side up to a maximum value, and a uniform lamination number section from the radius point where the number of overlapping layers reaches the maximum value to the radius point where the innermost segment is present.

77. The first tab coupling portion is The battery of claim 76, wherein the battery is bonded to the bent surface so as to overlap the uniform stacking section.

78. The battery of claim 77, wherein the number of overlapping layers in the uniform stacking number section is 10 or more.

79. the first tab connection portion is welded to the bent surface; 79. The battery of claim 78, wherein the welded region of the tab bond overlaps the stack count uniform section by at least 50% along the radial direction of the electrode assembly.

80. The battery according to claim 4 , wherein the first uncoated portion and the first tab connection portion are connected by welding along the radial direction of the electrode assembly.

81. 81. The battery of claim 1, wherein the first tab connection portion is welded to the first plain portion in a state parallel to the bottom surface of the battery housing.

82. 81. The battery of claim 80, wherein the weld bead formed between the first uncoated portion and the first tab bonded portion forms a linear weld pattern extending along a radial direction of the electrode assembly.

83. a weld bead formed between the first uncoated portion and the first tab coupling portion forms a weld pattern; 83. The battery of any one of claims 80 to 82, wherein the welding pattern is a line of connected spot welds.

84. 84. The battery of any one of claims 80 to 83, wherein a width of a weld bead formed between the first plain portion and the first tab bond is 0.1 mm or greater.

85. The first tab coupling portion and the first housing coupling portion are each provided in plural numbers, 85. The battery of claim 1, wherein the plurality of first tab connections and first housing connections are arranged in a radial pattern, a cross pattern, or a combination thereof, relative to the center of the first current collector.

86. 86. The battery of claim 85, wherein each of the plurality of first housing joints is disposed between adjacent first tab joints.

87. The first housing coupling portion is provided in plurality, The battery according to claim 4 , wherein the first contact portions of the first housing coupling portions are integrally formed by being connected to each other.

88. The battery of claim 4 , wherein an outermost point of the first connecting portion is spaced apart from an innermost point of the beading portion by a predetermined distance.

89. The battery according to claim 31 , wherein the first bent portion forms an acute angle between the first contact portion and the first connecting portion.

90. The battery according to claim 3 , wherein the battery has a plurality of liquid injection holes.

91. The battery according to claim 90, wherein the plurality of liquid injection holes are arranged symmetrically with respect to the center of the first tab coupling portion in the width direction.

92. The battery of claim 91, wherein a weld bead for joining the first tab joining portion and the first plain portion is formed between the liquid filling holes arranged symmetrically on both sides.

93. The first tab coupling portion is 4. The battery according to claim 3, wherein the width at a position spaced a predetermined distance from the connection portion toward the longitudinal end of the first tab connection portion is wider than the width at the connection portion between the first tab connection portion and the support portion.

94. 94. The battery of claim 93, wherein the liquid injection hole is formed at a position spaced a predetermined distance from the connecting portion toward the longitudinal end of the first tab coupling portion.

95. At least a part of the region where the liquid injection hole is formed is 95. The battery of claim 94, wherein the width at a position spaced a predetermined distance from the connection portion toward the end of the first tab connection portion is wider than the width at the connection portion between the first tab connection portion and the support portion, and the increased area is included in the battery.

96. 96. The battery of any one of claims 3 to 95, wherein a longitudinal end of the first tab connection portion has an arcuate shape that conforms to an inner peripheral surface of the battery housing.

97. 83. The battery of claim 82, wherein an extension direction of a weld pattern formed between the first plain portion and the first tab coupling portion and an extension direction of a weld pattern formed between the beading portion and the first contact portion are perpendicular to each other.

98. 73. The battery of any one of claims 62 to 72, wherein the innermost point of the beading portion is located radially further inward than the end of the crimping portion.

99. the sealing gasket encases the housing cover; 73. A battery as described in any one of claims 64 to 72, wherein the radial length of the portion of the sealing gasket that covers the lower surface of the housing cover is shorter than the radial length of the portion of the sealing gasket that covers the upper surface of the housing cover.

100. The total radial length of the first tab coupling portion is T, The outer diameter of the electrode assembly is defined as JR, When the height of the outermost segment of the electrode assembly is F, the following equation (5) is satisfied: [Formula 5] JR-2×F≦T<JR 100. The battery of any one of claims 75 to 99, wherein

101. 101. The battery according to claim 1, wherein a ratio of an area of ​​the first current collector that is not in contact with the upper surface of the electrode assembly to an area of ​​a circle having a diameter equal to the outer diameter of the electrode assembly is 30% or more and less than 100%.

102. 102. The battery according to claim 1, wherein a ratio of an area of ​​the first current collector that is not in contact with the electrode assembly to an area of ​​a circle having a diameter equal to the outer diameter of the electrode assembly is 60% or more and less than 100%.

103. 43. The battery according to claim 40, wherein the diameter of the current collector holes is smaller than the diameter of the winding holes provided in the core of the electrode assembly.

104. When the diameter of the winding hole is R3, 104. The battery of claim 103, wherein the diameter of the current collector hole is greater than or equal to 0.5×R3 and less than R3.

105. When the diameter of the winding hole is R3, 105. The battery of claim 103 or 104, wherein the diameter of the current collector hole is greater than or equal to 0.7×R3 and less than R3.

106. 106. The battery of any one of claims 1 to 105, wherein the battery has a form factor ratio of diameter divided by height greater than 0.

4.

107. 107. The battery of any one of claims 1 to 106, wherein the resistance measured between the positive electrode and the negative electrode is 4 mΩ or less.

108. An electrode assembly in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding shaft to define a core and an outer circumferential surface, the first electrode including a first uncoated portion in which an active material layer is not coated along the winding direction; a battery housing having an opening on one side thereof and accommodating the electrode assembly through the opening; a current collector electrically connected to the first uncoated portion and the inner surface of the battery housing, the current collector includes a first portion in contact with the inner surface of the battery housing and a second portion coupled to the first uncoated portion; When the central region of the first portion is viewed from a plane on which the second portion exists, the central region of the first portion and the second portion are spaced apart from each other in a circumferential direction of the electrode assembly, the battery housing has a beading portion formed at an end adjacent to the opening and pressed inward; The battery, wherein the first portion is bonded onto the beading portion.

109. The battery further includes a sealing gasket interposed between the open portion of the battery housing and the current collector, 109. The battery of claim 108, wherein the first portion is interposed between an inner surface of the battery housing and the sealing gasket.

110. 110. The battery of claim 108 or 109, wherein the first portion and the second portion are located on different planes in the winding axis direction of the electrode assembly.

111. 111. A battery pack comprising a plurality of cells according to any one of claims 1 to 110.

112. The plurality of batteries are arranged in a predetermined number of rows, 112. The battery pack of claim 111, wherein the terminals of each battery and the outer surface of the bottom of the battery housing are arranged facing upward.

113. a plurality of bus bars connecting the plurality of batteries in series and parallel; each of the plurality of bus bars is disposed above an adjacent battery; Each of the plurality of bus bars is a body portion extending between adjacent terminals; a plurality of first bus bar terminals extending to one side of the body portion and electrically coupled to electrode terminals of batteries located on the one side; A battery pack as described in claim 112, including: a plurality of second bus bar terminals extending to the other side of the body portion and electrically coupled to the outer surface of the bottom of the battery housing of the battery located on the other side.

114. 114. A motor vehicle comprising a battery pack according to any one of claims 111 to 113.

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