Battery, current collector for battery, battery pack including current collector, and automobile

Abstract

This invention provides a battery and a current collector for use in the battery, a battery pack including the current collector, and an automobile. The battery includes: an electrode assembly having a first electrode, a second electrode, and a separator membrane between them wound around a winding shaft to define a core and an outer peripheral surface; the first electrode having a first uncoated portion at its long side end along the winding direction, the first uncoated portion being exposed to the outside of the separator membrane, at least a portion of the first uncoated portion itself serving as an electrode tab; a housing having an opening on one side through which the electrode assembly is received; a first current collector including: an edge portion disposed on the upper part of the electrode assembly; a first uncoated portion bonding portion extending inward from the edge portion and bonding with the first uncoated portion; a terminal bonding portion disposed separately from the first uncoated portion bonding portion; and a terminal bonding portion bonded to the terminal bonding portion.

Description

Technical Field

[0001] This invention relates to batteries and current collectors used in batteries, battery packs including the current collectors, and automobiles. More specifically, this invention relates to batteries that, even when subjected to external impacts or vibrations during the use of secondary batteries, prevent force concentration at welded joints between components, and to current collectors used in such batteries, battery packs including the current collectors, and automobiles. Background Technology

[0002] The applications of rechargeable batteries are very diverse. For example, battery packs used in devices such as electric vehicles require large capacity and high power. Furthermore, such high-capacity, high-power battery packs may be cylindrical cells, for instance, used as individual battery units.

[0003] In the case of cylindrical batteries with high capacity and high power, electrode tabs are provided on both sides of the electrode assembly to improve current collection efficiency, and current collectors are attached to both sides of the electrode assembly. By applying this structure, the contact area between the electrode tabs and the current collector is maximized, thereby minimizing the resistance at the connection points between components.

[0004] As mentioned above, when cylindrical batteries are used in devices such as automobiles, they are frequently subjected to external impacts and vibrations during use, which can cause damage to the joints used for electrical connections between components. Such damage to the joints leads to product defects.

[0005] Alternatively, even if the electrical connection is not completely severed due to damage to the joint used for electrical connection, but a portion of the welded part is damaged, resulting in a reduction in the joint area between components, excessive heat is generated due to increased resistance, which in turn causes deformation of the component and leads to an internal short circuit.

[0006] Therefore, there is a need to develop a cylindrical battery structure that can prevent force concentration at the joints between components even when subjected to external impacts and / or vibrations during use.

[0007] On the other hand, in the case of a cylindrical battery, an insulator, i.e., a separator membrane, is placed between the anode and the cathode. This membrane is rolled up to form an electrode assembly in the shape of a gel roll, which, along with the electrolyte, is inserted into the interior of the casing to constitute the battery. Furthermore, strip-shaped electrode tabs are connected to the uncoated portions of both the anode and the cathode, electrically connecting the electrode assembly to the exposed electrode terminals. For reference, the anode electrode terminal is a cover plate of a sealing body that seals the opening of the casing, and the cathode electrode terminal is the casing itself.

[0008] However, in conventional cylindrical batteries with such a structure, the current is concentrated on the strip-shaped electrode tabs where the uncoated anode and / or uncoated cathode are joined, resulting in higher resistance, more heat generation, and poor current collection efficiency.

[0009] In small cylindrical batteries with form factors of 1865 or 2170, resistance and heat generation are not major issues. However, when increasing the form factor to apply cylindrical batteries to electric vehicles, a significant amount of heat can occur around the electrode tabs during rapid charging, potentially leading to fires in the cylindrical batteries.

[0010] To address this problem, a cylindrical battery with the following structure (so-called tab-less cylindrical battery) was developed: it is designed with an uncoated anode portion and an uncoated cathode portion at the upper and lower ends of the electrode assembly, respectively, and the current collector is welded to such uncoated portions to improve the current collection efficiency.

[0011] Figures 1 to 3 This diagram illustrates the manufacturing process of a tabless cylindrical battery. Figure 1 This indicates the structure of the electrode plates. Figure 2 This indicates the winding process of the electrode plates. Figure 3 This refers to the process of welding the current collector to the bent surface of the uncoated part. Figure 4 This is a cross-sectional view of a tabless cylindrical battery cut along its length (Z-axis).

[0012] Reference Figures 1 to 4 The anode plate 210 and the cathode plate 211 have a structure in which an active material 221 is coated on the sheet-like current collector 220, and an uncoated portion 222 is included on one long side along the winding direction X.

[0013] like Figure 2 As shown, electrode assembly A is manufactured by sequentially stacking an anode plate 210 and a cathode plate 211 together with two separation membranes 212 and then winding them in one direction X. At this time, the uncoated portions of the anode plate 210 and the uncoated portions of the cathode plate 211 are arranged in opposite directions.

[0014] After the winding process, the uncoated portion 210a of the anode plate 210 and the uncoated portion 211a of the cathode plate 211 are bent toward the core side. Then, current collectors 230 and 231 are welded to the uncoated portions 210a and 211a, respectively.

[0015] No additional electrode tabs are attached to the uncoated anode portion 210a and the uncoated cathode portion 211a. The current collectors 230 and 231 are connected to external electrode terminals. The current path is formed with a large cross-sectional area along the winding axis direction of the electrode assembly A (refer to the arrow), thus reducing the battery resistance. This is because resistance is inversely proportional to the cross-sectional area of ​​the current flow path.

[0016] However, when the shape factor of the cylindrical battery increases and the charging current increases during rapid charging, heat generation problems arise in tabless cylindrical batteries.

[0017] Specifically, such as Figure 4 As shown, the conventional tabless cylindrical battery 240 includes a housing 241 and a sealing body 242. The sealing body 242 includes a cover plate 242a, a sealing gasket 242b, and a connecting plate 242c. The sealing gasket 242b surrounds the edge of the cover plate 242a and is fixed by a crimping portion 243. In addition, the electrode assembly A is fixed inside the housing 241 by a rolled edge portion 244 to prevent vertical movement.

[0018] Typically, the anode terminal is the cover plate 242a of the sealing body 242, and the cathode terminal is the housing 241. Therefore, the current collector 230, which is attached to the uncoated portion 210a of the anode plate 210, is electrically connected to the connecting plate 242c attached to the cover plate 242a via a strip-shaped lead 245. Additionally, the current collector 231, which is attached to the uncoated portion 211a of the cathode plate 211, is electrically connected to the bottom of the housing 241. An insulator 246 covers the current collector 230 to prevent the housing 241 and the uncoated portion 210a of the anode plate 210, which have different polarities, from contacting each other and causing a short circuit.

[0019] A strip-shaped lead 245 is used when connecting the current collector 230 to the connecting plate 242c. The lead 245 is attached separately to the current collector 230 or formed integrally with the current collector 230. However, the lead 245 is a thin strip, so its cross-sectional area is small, and it generates more heat when a rapid charging current flows. In addition, the excessive heat generated by the lead 245 is transferred to the electrode assembly A side, causing the separation membrane 212 to shrink, which is the main cause of thermal runaway, namely internal short circuit.

[0020] The lead wire 245 occupies a considerable amount of space within the housing 241. Therefore, the space efficiency of the battery 240, including the lead wire 245, is low, thus limiting the potential for increasing energy density.

[0021] Furthermore, in the past, to connect the tabless cylindrical batteries 240 in series and / or parallel, bus components needed to be connected to the cover plate 242a of the sealing body 242 and the bottom surface of the outer casing 241, resulting in reduced space efficiency. Battery packs in electric vehicles comprise hundreds of cylindrical batteries 240. Therefore, the inefficiency of the electrical wiring makes the assembly process of electric vehicles and the maintenance of the battery packs very troublesome.

[0022] On the other hand, in recent years, with the application of cylindrical batteries in electric vehicles, the shape factor of cylindrical batteries has been increased. That is, compared with the previous cylindrical batteries with shape factors of 1865 and 2170, the diameter and height of cylindrical batteries have been increased. The increase in shape factor leads to an increase in energy density, improved safety against thermal runaway, and improved cooling efficiency.

[0023] The energy density of cylindrical batteries is further increased by increasing the form factor and minimizing unnecessary space inside the casing. Therefore, components used for electrical insulation between the electrode assembly and the casing, or for collecting current from the anode and cathode plates, also need to be optimally designed to increase battery capacity and reduce overall battery resistance. Summary of the Invention

[0024] The problem that the invention aims to solve

[0025] The present invention was developed in view of the above-mentioned problems. The purpose of the present invention is that, even if an external impact and / or vibration is applied during the use of a secondary battery, the impact and / or vibration will not be concentrated in a specific part but will be dispersed, thereby preventing damage at the joint between components.

[0026] On the other hand, another objective of the present invention is that, even without the addition of a current cut-off component, the current cut-off function is performed by the current collector itself, thereby quickly cutting off the current when an overcurrent occurs due to a short circuit or the like, thus ensuring the safety of the secondary battery in use.

[0027] In another aspect, one object of the present invention is to provide a battery with a structure in which the anode terminal and the cathode terminal are applied in the same direction.

[0028] In another aspect, another object of the present invention is to use the wide surface of the closing portion of the housing as an electrode terminal when multiple batteries are electrically connected in one direction, thereby ensuring sufficient area for welding electrical connection components such as buses used to manufacture battery packs and electrode terminals of the batteries.

[0029] In another aspect, the object of the present invention is to minimize the resistance of the battery by improving the structure of the uncoated portion of the electrode assembly, increasing the contact area between the electrode assembly and the current collector (first current collector) and / or the contact area between the terminal and the current collector (first current collector).

[0030] However, the technical problems to be solved by the present invention are not limited to the above-mentioned problems. Those skilled in the art can clearly understand other problems not mentioned herein through the invention description below.

[0031] Methods for solving problems

[0032] A battery according to an embodiment of the present invention for solving the above-mentioned problems includes: an electrode assembly that is a core and an outer peripheral surface defined by winding a first electrode, a second electrode, and a separator membrane between them around a winding shaft, wherein the first electrode includes a first uncoated portion at its long side end along the winding direction, which is not coated with an active material layer and is exposed to the outside of the separator membrane, and at least a portion of the first uncoated portion itself serves as an electrode tab; a housing that includes an opening on one side through which the electrode assembly is housed; a first current collector that includes: an edge portion disposed on the upper part of the electrode assembly; a first uncoated portion bonding portion that extends inward from the edge portion and is bonded to the first uncoated portion; a terminal bonding portion that is disposed separately from the first uncoated portion bonding portion; and a terminal that is bonded to the terminal bonding portion.

[0033] The aforementioned edge portion has a frame shape with its inner space empty.

[0034] The first uncoated portion and the terminal portion are electrically connected via the edge portion.

[0035] The aforementioned terminal joint is located at the center of the inner space of the aforementioned edge portion.

[0036] The first current collector further includes a connecting portion that extends inward from the edge portion and connects to the terminal junction portion.

[0037] At least a portion of the aforementioned connecting portion has a smaller cross-sectional area compared to the aforementioned first uncoated portion joint portion.

[0038] At least a portion of the aforementioned connecting portion is smaller in either width or thickness than the aforementioned first uncoated portion joint portion.

[0039] The aforementioned connecting portion has a tapered portion, the width of which narrows continuously or in stages from the inner side of the aforementioned edge portion along the direction toward the aforementioned terminal joint portion.

[0040] It has multiple joints of the aforementioned first uncoated portion.

[0041] The plurality of the aforementioned first uncoated portions are regularly arranged together along the extension direction of the aforementioned edge portions.

[0042] The extension lengths of the various first uncoated portions are substantially the same.

[0043] The cross-sectional areas of the various first uncoated portions mentioned above are substantially the same.

[0044] The width and thickness of each of the aforementioned first uncoated portions are substantially the same.

[0045] The aforementioned terminal joint is surrounded and arranged by a plurality of the aforementioned first uncoated joints.

[0046] The aforementioned connecting portion is disposed between a pair of adjacent first uncoated portions.

[0047] The distance from the connecting portion along the extending direction of the edge portion to either of the two adjacent first uncoated portion joints is substantially the same as the distance to the other first uncoated portion joint.

[0048] The aforementioned connecting parts are multiple.

[0049] The aforementioned connecting portions are respectively disposed between a pair of adjacent first uncoated portions.

[0050] The aforementioned connecting portions are regularly arranged to each other along the extending direction of the aforementioned edge portions.

[0051] The distance from the aforementioned multiple connecting portions along the extension direction of the aforementioned edge portions to any one of the aforementioned adjacent first uncoated portion joints is substantially the same as the distance to the other first uncoated portion joint.

[0052] The aforementioned connection portion includes a current cutting-off portion formed in a manner that reduces the cross-sectional area of ​​the aforementioned connection portion.

[0053] The aforementioned current cutting-off portion is a region having a shape in which at least one of its width and thickness is reduced compared to the remaining region of the aforementioned connecting portion.

[0054] The aforementioned current cutting-off portion includes at least one of a recess, a groove, and a through hole formed on at least one side of the aforementioned connection portion.

[0055] The aforementioned terminal joint is positioned at a location corresponding to the hole formed in the winding center portion of the aforementioned electrode assembly.

[0056] The terminal connection portion has a structure that covers the hole formed in the winding center portion of the electrode assembly, so that the hole formed in the winding center portion of the electrode assembly is not exposed to the outside of the terminal connection portion.

[0057] The diameter of the terminal joint is greater than or equal to the diameter of the hole formed in the winding center portion of the electrode assembly.

[0058] The first uncoated portion extends toward the closed portion located on the opposite side of the open portion of the housing.

[0059] The first uncoated portion is joined to the joint surface formed by bending the end of the first uncoated portion along a direction parallel to the first current collector.

[0060] The battery also includes a cover plate that seals the opening of the outer casing.

[0061] The cover plate is not electrically connected to the electrode assembly and therefore does not have polarity.

[0062] The aforementioned outer casing includes: a rolled edge portion which is formed adjacent to the aforementioned open portion and is pressed into the inner side of the aforementioned outer casing; and a press-fit portion which is formed at the lower part of the rolled edge portion and extends and bends around the edge of the aforementioned cover plate.

[0063] It also includes a sealing gasket disposed within the aforementioned pressing portion, between the aforementioned housing and the aforementioned cover plate.

[0064] The aforementioned terminal passes through the closed portion located on the opposite side of the aforementioned open portion of the aforementioned housing.

[0065] The aforementioned terminal passes through the center of the aforementioned closing portion.

[0066] The aforementioned terminals are insulated from the aforementioned housing.

[0067] An insulating pad is placed between the aforementioned housing and the aforementioned terminals.

[0068] It also includes an insulator located between the closed portion, which is situated on the opposite side of the open portion of the aforementioned housing, and the aforementioned first current collector.

[0069] The insulator has a thickness corresponding to the distance between the inner surface of the closing portion of the housing and the first current collector.

[0070] The aforementioned terminals are connected to the terminal connection portion of the first current collector through holes formed in the aforementioned insulator.

[0071] The lower end of the terminal connected to the aforementioned terminal joint is located at substantially the same height as or closer to the upper part of the lower surface of the aforementioned insulator.

[0072] The aforementioned insulator is located between the aforementioned first uncoated portion and the sidewall of the aforementioned housing.

[0073] The upper surface of the insulator is in contact with the inner surface of the closed portion located on the opposite side of the open portion of the housing, and the lower surface of the insulator is in contact with the upper surface of the first current collector.

[0074] The second electrode further includes, at its long side end, a second uncoated portion along the winding direction, which is not coated with an active material layer. The second uncoated portion extends in the opposite direction to the first uncoated portion and is exposed to the outside of the separation membrane.

[0075] The aforementioned outer casing is electrically connected to the aforementioned second uncoated portion.

[0076] The battery further includes a second current collector, which is respectively coupled to the second uncoated portion and the outer casing, electrically connecting the second uncoated portion and the outer casing.

[0077] The second current collector described above includes a second current collector hole, which is formed in a region corresponding to the hole formed in the winding center of the electrode assembly described above.

[0078] The second current collector hole has the same or larger diameter as the hole formed at the winding center of the electrode assembly, so as not to block the hole formed at the winding center of the electrode assembly.

[0079] The second current collector includes: a second uncoated portion joining portion, which is joined to the second uncoated portion; and a housing joining portion, which is joined to the housing.

[0080] The aforementioned second uncoated portion and the aforementioned joint portion of the second uncoated portion are joined together by welding.

[0081] The aforementioned outer shell and the aforementioned outer shell joint are joined together by welding.

[0082] The aforementioned outer casing has a rolled edge portion, which is formed adjacent to the aforementioned open portion and has a shape that is pressed inward.

[0083] The aforementioned outer casing joint is electrically bonded to the lower surface of the aforementioned rolled edge portion.

[0084] The distance from the center of the first current collector to the outermost part of the edge portion is longer than the distance from the center of the second current collector to the outermost part of the second uncoated portion joint.

[0085] The distance from the center of the second current collector to the outermost part of the second uncoated portion joint is less than or equal to half the inner diameter of the area where the rolled edge of the outer shell is formed.

[0086] At least a portion of the first uncoated portion includes a plurality of segmented pieces divided along the winding direction of the electrode assembly, the plurality of segmented pieces being bent along the radial direction of the electrode assembly.

[0087] The aforementioned curved segmented pieces overlap to form multiple layers.

[0088] The electrode assembly has a welding target area, which is an area in which the number of overlapping segments of the first uncoated portion is maintained at a certain number along the radial direction of the electrode assembly.

[0089] At least a portion of the second uncoated portion includes a plurality of segmented pieces divided along the winding direction of the electrode assembly, the plurality of segmented pieces being bent along the radial direction of the electrode assembly.

[0090] The aforementioned curved segmented pieces overlap to form multiple layers.

[0091] The electrode assembly described above has a welding target area, which is an area in which the number of overlapping segments of the second uncoated portion is maintained at a certain number along the radial direction of the electrode assembly.

[0092] The first current collector further includes a bridging portion that connects at least one of the following: adjacent first uncoated portion joints, adjacent first uncoated portion joints and connecting portions, and adjacent connecting portions.

[0093] The aforementioned bridging portion is positioned further inward than the aforementioned edge portion.

[0094] The first current collector has an impregnation hole formed between the edge portion and the bridging portion.

[0095] The impregnation hole has a slit shape that extends along the extension direction of the edge portion.

[0096] The ratio of the area of ​​the first current collector that does not contact the upper surface of the electrode assembly to the area of ​​a circle with the outer diameter of the electrode assembly is 20% or more and less than 100%.

[0097] The number of the aforementioned connecting parts is one or two.

[0098] The ratio of the cross-sectional area of ​​the connecting portion in the region where the current cutting portion is formed to the cross-sectional area of ​​the connecting portion in the region adjacent to the region where the current cutting portion is formed is 0.6 to 0.9.

[0099] The ratio of the cross-sectional area of ​​the aforementioned connecting portion to the cross-sectional area of ​​the aforementioned first uncoated portion joint portion is 0.2 to 1.0.

[0100] The ratio of the outer diameter of the first current collector to the inner diameter of the outer casing is in the range of 33% to 98.5%.

[0101] The aforementioned welding target area is the area where the number of overlapping layers of the aforementioned multiple segmented pieces remains the largest.

[0102] The first current collector is welded to the first uncoated portion in such a way that it overlaps with the welding target area by at least 50%.

[0103] The aforementioned welding target area is the area where the number of overlapping layers of the aforementioned multiple segmented pieces remains the largest.

[0104] The second current collector is welded to the second uncoated portion in such a way that it overlaps with the welding target area by at least 50%.

[0105] The resistance measured between the anode and cathode is 4 mΩ or less. This resistance can be 0.5 mΩ or more and 4 mΩ or less, preferably 1 mΩ or more and 4 mΩ or less.

[0106] The aforementioned current-cutting portion is formed at a location that is separated from the core of the aforementioned electrode assembly by 40% to 90% along the radial direction based on the radius of the electrode assembly.

[0107] At least a portion of the first uncoated portion includes a plurality of segmented pieces divided along the winding direction of the electrode assembly. The plurality of segmented pieces are bent and overlapped in multiple layers along the radial direction of the electrode assembly. The current cutting portion is provided in a region corresponding to the welding target region, which is a region in which a certain number of overlaps of the segmented pieces of the first uncoated portion are maintained along the radial direction of the electrode assembly.

[0108] A belt is attached to the aforementioned current cutting section.

[0109] The strip mentioned above is made of polyimide.

[0110] The aforementioned strip is configured to surround the aforementioned connection portion in the region where the aforementioned current cutting-off portion is formed.

[0111] In the aforementioned battery, when the outer diameter of the first current collector is set to T, the outer diameter of the electrode assembly is set to JR, and the height of the segment located at the outermost edge of the electrode assembly in the radial direction is set to F, the following relationship is satisfied: JR–2 F≤T <JR。

[0112] The welding pattern drawn by the weld bead formed on one side of the terminal joint of the first current collector has a shape that surrounds the center of the bottom surface of the terminal.

[0113] The above welding patterns can be formed continuously or discontinuously.

[0114] The tensile force of the weld between the terminal joint of the first current collector and the bottom surface of the terminal is 2 kgf or more.

[0115] The equivalent diameter of the weld pattern drawn by the weld bead formed on one side of the terminal joint of the first current collector is 2 mm or more.

[0116] The diameter of the flat portion formed on the bottom surface of the aforementioned terminal is 3 mm to 14 mm.

[0117] The ratio of the area of ​​the weld pattern drawn by the weld bead formed on the surface of the terminal joint of the first current collector to the area of ​​the flat portion formed on the bottom surface of the terminal is 2.04% to 44.4%.

[0118] The second current collector hole has a smaller diameter than the hole formed at the winding center of the electrode assembly.

[0119] When the diameter of the aforementioned winding hole is set to R3, the diameter of the aforementioned second current collector hole is 0.5. R3 or higher and less than R3.

[0120] When the diameter of the aforementioned winding hole is set to R3, the diameter of the aforementioned second current collector hole is 0.7. R3 or higher and less than R3.

[0121] The ratio of the shape factor obtained by dividing the diameter of the battery by its height is greater than 0.4.

[0122] The length of the welded portion that joins the first uncoated portion and the first uncoated portion along the radial direction of the electrode assembly is longer than the length of the welded portion that joins the second uncoated portion and the second uncoated portion along the radial direction of the electrode assembly.

[0123] Based on the core of the electrode assembly, the distance to the starting point of the welded portion that joins the first uncoated portion and the first uncoated portion is substantially the same as the distance to the starting point of the welded portion that joins the second uncoated portion and the second uncoated portion.

[0124] Multiple current-cutting sections are provided along the length of the connection section.

[0125] No welded portion is formed at the connection between the aforementioned edge portion and the aforementioned terminal portion.

[0126] In addition, a battery pack according to an embodiment of the present invention includes: a battery according to an embodiment of the present invention; and a packaging shell that houses a plurality of the batteries.

[0127] Multiple batteries are arranged in a predetermined number of columns, with the terminals of each battery and the outer surface of the closed portion of the housing located on the opposite side of the open portion of the housing facing upwards.

[0128] The battery pack includes multiple buses that connect multiple batteries in series and in parallel. The multiple buses are arranged on the upper part of the multiple batteries. Each bus includes: a main body that extends between the terminals of adjacent batteries; multiple first bus terminals that extend in one direction of the main body and are electrically connected to the terminals of the batteries located in the one direction; and multiple second bus terminals that extend in another direction of the main body and are electrically connected to the outer surface of the closing portion of the casing of the batteries located in the other direction.

[0129] The vehicle of an embodiment of the present invention includes a battery pack as described above in one embodiment of the present invention.

[0130] Invention Effects

[0131] According to one aspect of the invention, during the use of the secondary battery, even if external impact and / or vibration are applied, the impact and / or vibration will not be concentrated in a specific part but will be dispersed, thereby preventing damage at the joint between components.

[0132] On the other hand, according to another aspect of the present invention, even without the addition of a current-cutting component, the current-cutting function can be performed by the current collector itself. Thus, when an overcurrent occurs due to a short circuit or the like, the current can be quickly cut off, ensuring the safety of the secondary battery in use.

[0133] According to another aspect of the invention, the electrode terminal structure of the battery is improved, and the cross-sectional area of ​​the current path is increased, thereby improving the internal heat generation problem during rapid charging.

[0134] According to another aspect of the invention, electrical wiring for connecting batteries in series and / or parallel can be performed on one side of the battery.

[0135] According to another aspect of the invention, when multiple batteries are electrically connected in one direction, the wide surface of the closing portion of the housing can be used as an electrode terminal, thereby ensuring sufficient area for welding electrical connection components such as busbars used in the manufacture of battery packs and the electrode terminals of the batteries.

[0136] According to another aspect of the invention, by improving the structure of the uncoated portion of the electrode assembly, the contact area between the electrode assembly and the current collector (first current collector) and / or the contact area between the terminal and the current collector (first current collector) is increased, thereby minimizing the resistance of the battery.

[0137] However, the effects of the present invention are not limited to those described above, and those skilled in the art can clearly understand other technical effects not mentioned herein through the following description of the invention. Attached Figure Description

[0138] The accompanying drawings illustrate preferred embodiments of the invention and, together with the specific embodiments described below, further aid in understanding the technical concept of the invention. Therefore, the invention is not limited to the matters shown in the drawings.

[0139] Figure 1 This is a top view showing the structure of the electrode plates used in conventional tabless cylindrical batteries.

[0140] Figure 2 This diagram illustrates the winding process of an electrode assembly, which is included in a conventional tabless cylindrical battery.

[0141] Figure 3 It means Figure 2 The diagram shows the process of welding the current collector to the bent surface of the uncoated part in the electrode assembly.

[0142] Figure 4 This is a cross-sectional view of a conventional tabless cylindrical battery cut along the length direction Z.

[0143] Figure 5 This is a diagram showing the appearance of a cylindrical battery according to an embodiment of the present invention.

[0144] Figure 6 This is a cross-sectional view showing the internal structure of a cylindrical battery according to an embodiment of the present invention.

[0145] Figure 7 This is a partial cross-sectional view showing the upper structure of a cylindrical battery according to an embodiment of the present invention.

[0146] Figure 8 This is an enlarged view of the upper part of the electrode assembly of the present invention.

[0147] Figure 9 It is Figure 8 An enlarged view of the upper part of the uncoated section.

[0148] Figure 10 and Figure 11 The diagram showing the connection between the first current collector and the terminal is based on... Figure 7 and Figure 7 The top view is observed from the direction of the arrow.

[0149] Figures 12 to 15 The diagram illustrates various configurations of a current collector (first current collector) according to one embodiment of the present invention.

[0150] Figures 16 to 20 The diagram illustrates various configurations of a current collector (first current collector) according to another embodiment of the present invention (structure in which the current collector has a current cutting-off portion).

[0151] Figure 21 The diagram illustrates various configurations of a current collector (first current collector) according to another embodiment of the present invention (structure in which a covering member is applied to the current cutting section).

[0152] Figure 22 It means possessing and Figures 12 to 15 The diagram shows different structures of the current collector (first current collector) (with added bridging sections).

[0153] Figure 23 This is a partial cross-sectional view showing the lower structure of a cylindrical battery according to an embodiment of the present invention.

[0154] Figure 24 This is a diagram showing the lower surface of a cylindrical battery according to an embodiment of the present invention.

[0155] Figure 25 This is a diagram illustrating an exemplary configuration of the second current collector applied to the present invention.

[0156] Figure 26 This is a top view illustrating the electrode structure of a preferred embodiment of the present invention.

[0157] Figure 27 This is a cross-sectional view of an electrode assembly in which the uncoated portion of the first electrode of an embodiment of the present invention is cut along the length direction Z and applied to the second electrode.

[0158] Figure 28 This is a cross-sectional view of the electrode assembly with the bent, uncoated portion cut along the length direction Z according to an embodiment of the present invention.

[0159] Figure 29 This is a perspective view of an electrode assembly with a bent uncoated portion according to an embodiment of the present invention.

[0160] Figure 30 This is a top top view showing how multiple cylindrical batteries of an embodiment of the present invention are connected in series and parallel using a bus.

[0161] Figure 31 This is a diagram showing a schematic structure of a battery pack including a cylindrical battery according to an embodiment of the present invention.

[0162] Figure 32This is a diagram illustrating a schematic structure of a car including a battery pack according to an embodiment of the present invention.

[0163] (Symbol Explanation)

[0164] 5: Cars

[0165] 3: Battery pack

[0166] 2: Packaging outer shell

[0167] 1: Cylindrical battery

[0168] 150: Bus

[0169] 151: Main Body

[0170] 152: First bus terminal

[0171] 153: Second bus terminal

[0172] 10: Electrode Assembly

[0173] 11: First Uncoated Section

[0174] 11a: Segmented Piece

[0175] 12: Second uncoated section

[0176] C: Winding Center

[0177] 20: Outer shell

[0178] 20a: External surface (second electrode terminal)

[0179] 21: Rolled edge

[0180] 21a: Upper rolled edge

[0181] 21b: Lower rolled edge

[0182] 22: Crimping section

[0183] 30: Cover plate

[0184] 31: Exhaust section

[0185] G1: Sealing gasket

[0186] 40: Current collector (first current collector)

[0187] 41: Edge

[0188] 42: First uncoated part joint

[0189] 43: Terminal joint

[0190] 44: Connecting part

[0191] 45: Bridging section

[0192] 40a: Impregnation hole

[0193] 44a: Conical part

[0194] N: Indentation (current cut-off section)

[0195] G: Slot (current cut-off section)

[0196] T: Through hole (current cut-off section)

[0197] 46: Covering components

[0198] 50: Terminal (First Electrode Terminal)

[0199] 51: Exposed terminal portion

[0200] 52: Terminal insertion section

[0201] 52a: Electrical connection part

[0202] 52b: Frame

[0203] G2: Insulating mat

[0204] GA: Exposed part of the gasket

[0205] GB: Gasket Insertion Part

[0206] 60: Insulator

[0207] 70: Current collector (second current collector)

[0208] 70a: Second collector hole

[0209] 71: Support section

[0210] 72: Second uncoated part joint

[0211] 72a: Injection Hole

[0212] 73: Outer shell joint

[0213] 73a: Contact part

[0214] 73b: Extension Detailed Implementation

[0215] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in this specification and claims should not be limited to their ordinary or dictionary meanings. The inventors, based on the principle that the concepts of terms can be appropriately defined in order to best illustrate their invention, interpret them as meanings and concepts consistent with the technical ideas of the present invention. Therefore, the embodiments described in this specification and the structures shown in the accompanying drawings are only some of the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, it should be understood at the time of this application that various equivalents and modifications may exist that can replace these.

[0216] Furthermore, to aid in understanding the invention, the accompanying drawings are not shown to scale, but rather with some of the constituent elements enlarged. Additionally, in different embodiments, the same reference numerals are used for the same constituent elements.

[0217] When referring to two objects as 'identical', it means 'substantially identical'. Therefore, substantially identical includes cases where there is a deviation considered low in the field, such as within 5%. Furthermore, uniformity of a parameter within a specified field means uniformity from an average perspective.

[0218] Reference Figure 5 and Figure 6 According to one embodiment of the present invention, a cylindrical battery 1 includes an electrode assembly 10, a casing 20, a cover plate 30, a current collector (first current collector) 40, and a terminal 50. In addition to the above-described components, the cylindrical battery 1 additionally includes a sealing gasket G1 and / or an insulating gasket G2 and / or an insulator 60 and / or a second current collector 70.

[0219] The electrode assembly 10 includes a first electrode having a first polarity, a second electrode having a second polarity, and a separation membrane between the first electrode and the second electrode. The first electrode is either an anode or a cathode, and the second electrode is equivalent to an electrode having a polarity opposite to that of the first electrode.

[0220] The electrode assembly 10 described above, for example, has an electrode assembly (jelly-roll) structure. That is, the electrode assembly 10 is manufactured by winding a laminate formed by stacking a sheet-like first electrode current collector and a second electrode current collector at least once with a separation membrane in between, in one direction with a winding center C as the reference. In this case, a separation membrane is additionally provided on the outer peripheral surface of the electrode assembly 10 to provide insulation between it and the housing 20. Any jelly-roll electrode assembly structure known in the art can be used in this invention.

[0221] 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 of the first electrode active material is present at one end of the first electrode current collector in the width direction (parallel to the Z-axis). Hereinafter, this uncoated portion, which serves as the first electrode tab, will be referred to as the first uncoated portion 11. The first uncoated portion 11 is located at the upper part of the electrode assembly 10 housed within the housing 20 in the height direction (parallel to the Z-axis). That is, the first electrode current collector includes a first uncoated portion 11 at its long side end, which is exposed to the outside of the separation membrane, and a portion of the first uncoated portion 11 itself serves as an electrode tab. The first uncoated portion 11 is, for example, an anode tab.

[0222] On the other hand, at least a portion of the first uncoated portion 11 includes a plurality of segmented pieces divided along the winding direction of the electrode assembly 10. In this case, the plurality of segmented pieces are bent along the radial direction of the electrode assembly 10. The bent plurality of segmented pieces overlap in multiple layers. In this case, the first uncoated portion bonding portion 42, described later, is bonded to the region where the plurality of segmented pieces overlap in multiple layers.

[0223] 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. An uncoated portion without the second electrode active material is present at the other end of the second electrode current collector in the width direction (parallel to the Z-axis). Hereinafter, this uncoated portion, serving as a second electrode tab, will be referred to as the second uncoated portion 12. The second uncoated portion 12 is located at the lower part of the electrode assembly 10 housed within the housing 20 in the height direction (parallel to the Z-axis). That is, the second electrode current collector includes a second uncoated portion 12 at its long side end, exposed to the outside of the separation membrane, and at least a portion of the second uncoated portion 12 itself serves as an electrode tab. The second uncoated portion 12 is, for example, an anode tab. On the other hand, at least a portion of the second uncoated portion 12 includes a plurality of segmented pieces divided along the winding direction of the electrode assembly 10. In this case, the plurality of segmented pieces are bent along the radial direction of the electrode assembly 10. The bent plurality of segmented pieces overlap to form multiple layers. In this case, the second current collector 70, described later, is incorporated into a region where multiple segmented pieces overlap to form multiple layers.

[0224] The first uncoated portion 11 and the second uncoated portion 12 extend in opposite directions along the height direction of the cylindrical battery 1 (parallel to the Z-axis). The first uncoated portion 11 extends toward the closed portion of the outer casing 20, and the second uncoated portion 12 extends toward the open portion of the outer casing 20.

[0225] In the present invention, with respect to the anode active material coated on the anode plate and the cathode active material coated on the cathode plate, any active material well known in the art can be used.

[0226] As an example, the anode active material comprises an alkali metal compound represented by the general chemical formula A[A x M y O 2+z (wherein A comprises at least one element selected from Li, Na and K; M comprises at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru and Cr; x≥0, 1≤x+y≤2, -0.1≤z≤2; the stoichiometric coefficients x, y and z enable the compound to maintain electrical neutrality).

[0227] As another example, the anode active material is an alkali metal compound xLiM 1 O2-(1-x)Li2M 2 O3 (M 1 comprises at least one element having an average oxidation state of 3; M 2 comprises at least one element having an average oxidation state of 4; 0≤x≤1).

[0228] As another example, the anode active material is represented by the general chemical formula Li a M 1 x Fe 1-x M 2 y P 1-y M 3 z O 4-z (wherein M 1 comprises at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg and Al; M 2 comprises 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 comprises a halogen element optionally comprising F; 0<a≤2, 0≤x≤1, 0≤y<1, 0≤z<1; the stoichiometric coefficients a, x, y and z enable the compound to maintain electrical neutrality) or a lithium metal phosphate represented by Li3M2(PO4)3 [wherein M comprises at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg and Al].

[0229] Preferably, the anolyte active material includes primary particles and / or secondary particles formed by condensing primary particles.

[0230] For example, cathode active materials can be carbon, lithium metal or lithium metal compounds, silicon or silicon compounds, tin or tin compounds, etc. Metal oxides such as TiO2 and SnO2 with potentials less than 2V can also be used as cathode active materials. As for carbon materials, low-crystalline carbon, highly crystalline carbon, etc. can be used.

[0231] As a separation membrane, porous polymer films can be used, such as porous polymer films made of polyolefin polymers such as ethylene polymers, propylene polymers, ethylene / butene copolymers, ethylene / hexene copolymers, and ethylene / methacrylate copolymers, used alone or in layers. As another example, as a separation membrane, conventional porous nonwoven fabrics such as nonwoven fabrics made of high-melting-point glass fibers or polyethylene terephthalate fibers can be used.

[0232] The separation membrane comprises a coating of inorganic particles on at least one surface. Alternatively, the separation membrane itself may also be composed of a coating of inorganic particles. The particles constituting the coating may have a structure in which they are bonded to the binder in a manner that creates an interstitial volume between adjacent particles.

[0233] The inorganic particles are composed of inorganic materials with a dielectric constant of 5 or higher. As a non-limiting example, the aforementioned inorganic particles include those selected from Pb(Zr,Ti)O3 (PZT), Pb... 1-x La x Zr 1-y Ti y O3 (PLZT), PB (Mg3Nb) 2 / 3 It refers to at least one substance in the group consisting of O3-PbTiO3 (PMN-PT), BaTiO3, hafniaHfO2, SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO and Y2O3.

[0234] Electrolytes are those with A + B - Salts with this structure. Here, A + Including Li + Na + K + Such alkali metal cations, or ions formed by combinations thereof. And B - Including the choice of F - Cl - ,Br - I -NO3 - N(CN)2 - BF4 - ClO4 - AlO4 - AlCl4 - PF6 - SbF6 - AsF6 - BF2C2O4 - BC4O8 - (CF3)2PF4 - (CF3)3PF3 - (CF3)4PF2 - (CF3) 5PF - (CF3) 6P - CF3SO3 - C4F9SO3 - CF3CF2SO3 - (CF3SO2)2N - (FSO2)2N - CF3CF2(CF3)2CO - (CF3SO2)2CH - (SF5) 3C - (CF3SO2)3C - CF3(CF2)7SO3 - CF3CO2 - CH3CO2, SCN - and (CF3CF2SO2)2N - Any one or more anions that make up the group.

[0235] Electrolytes can also be dissolved in organic solvents for use. Suitable organic solvents include propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone, or mixtures thereof.

[0236] Reference Figure 6 , Figure 7 and Figure 23 The aforementioned outer casing 20 is a generally cylindrical housing with an opening (open portion) formed at the bottom, and is made of a conductive material such as metal. The material of the outer casing 20 may include, for example, iron, stainless steel, or nickel-plated iron. The upper surface located on the opposite side of the opening is referred to as the closing portion. The sidewalls and closing portion of the outer casing 20 are formed as a single unit. Alternatively, the sidewalls and closing portion of the outer casing 20 may be formed separately and joined together by welding or the like. The upper surface of the outer casing 20 (the surface parallel to the XY plane), i.e., the outer surface 20a of the closing portion, has a generally flat shape. The outer casing 20 is housed in the electrode assembly 10 through the opening formed at the bottom, and the electrolyte is also housed within it.

[0237] The aforementioned housing 20 is electrically connected to the electrode assembly 10. For example, the housing 20 is electrically connected to the second uncoated portion 12 of the electrode assembly 10. In this case, the housing 20 has the same polarity as the second uncoated portion 12.

[0238] Reference Figure 6 and Figure 23The aforementioned outer casing 20 includes a rolled edge portion 21 and a pressing portion 22 formed at its lower end. The rolled edge portion 21 is located at the lower part of the electrode assembly 10. The rolled edge portion 21 is formed by pressing the outer peripheral surface of the outer casing 20 inward. Taking the innermost portion 21c of the rolled edge portion 21 located on the innermost side along the pressing direction as a reference, the upper rolled edge portion 21a and the lower rolled edge portion 21b located on the upper and lower parts respectively have asymmetrical shapes. Such asymmetrical shapes are formed during the process of compressing the outer casing 20 along the height direction (the direction parallel to the Z-axis) through a sizing process. The sizing process is a process of pressing the outer casing 20 along the winding axis direction of the electrode assembly 10 to match the height of the cylindrical battery 1 with the design shape factor.

[0239] The lower rolled edge portion 21b has a flat portion that is substantially parallel to the closing portion of the housing 20. Conversely, due to its asymmetrical formation, the upper rolled edge portion 21a has a shape that is at least partially inclined upward along the direction toward the innermost portion 21c. As a result, the upper rolled edge portion 21a presses and fixes the lower part of the electrode assembly 10. The rolled edge portion 21 is used as a support portion for mounting the cover plate 30 to prevent the electrode assembly 10, which has a size that substantially corresponds to the inner diameter of the housing 20, from being exposed through the opening formed at the lower end of the housing 20. The lower rolled edge portion 21b is used as a support portion for fixing the cover plate 30 and the contact portion 73a of the current collector (second current collector) 70, the sealing gasket G1, etc., as described later.

[0240] The aforementioned crimping portion 22 is formed at the lower part of the rolled edge portion 21. The crimping portion 22 extends from the lower rolled edge portion 21. The crimping portion 22 has a shape that extends and bends to surround the outer peripheral surface of the cover plate 30 disposed below the rolled edge portion 21 and a portion of the lower surface of the cover plate 30. The crimping portion 22 fixes the cover plate 30 and the sealing gasket G1.

[0241] However, the present invention does not preclude the case where the housing 20 does not have such a rolled edge portion 21 and / or a crimped portion 22. In the present invention, when the housing 20 does not have a rolled edge portion 21 and / or a crimped portion 22, the fixing of the electrode assembly 10 and / or the fixing of the cover plate 30 and / or the sealing of the housing 20 are achieved, for example, by the additional application of a component serving as a limiter for the electrode assembly 10 and / or the additional application of a structure for mounting the cover plate 30 and / or welding between the housing 20 and the cover plate 30.

[0242] On the other hand, the thickness of the aforementioned outer casing 20 varies depending on its location. The sidewall portion of the outer casing 20 is thinner than the closing portion. With this configuration, the diameter of the electrode assembly 10 can be further increased, which is advantageous from the perspective of energy density.

[0243] The closing portion of the aforementioned housing 20, which constitutes the upper surface, has a thickness of approximately 0.4 mm to 1.2 mm, more preferably approximately 0.6 mm to 1.0 mm. If the thickness of the closing portion of the housing 20 is too thin, deformation of the housing 20 may occur during internal pressure increases or welding. Conversely, if the thickness of the closing portion of the housing 20 is too thick, it is disadvantageous from the perspective of housing 20 processing and results in greater energy density loss. Therefore, it is necessary to set the thickness of the closing portion of the housing 20 to an appropriate level.

[0244] On the other hand, the sidewall portion constituting the outer peripheral surface of the aforementioned casing 20 has a thickness of approximately 0.3 mm to 0.8 mm, more preferably approximately 0.4 mm to 0.6 mm. If the thickness of the sidewall portion of the aforementioned casing 20 is too thin, the possibility of a fire spreading to adjacent cylindrical batteries 1 in the event of a fire or explosion of the cylindrical battery 1 increases. For example, in a battery pack comprising multiple cylindrical batteries 1, if an abnormality occurs and a fire or explosion occurs in some of the cylindrical batteries 1, if the thickness of the sidewall portion of the casing 20 is too thin, pinholes may be generated, thereby increasing the risk of a chain reaction of fires and explosions. Conversely, if the thickness of the sidewall portion of the aforementioned casing 20 is too thick, it is disadvantageous from the perspective of the processing of the casing 20, and the loss in terms of energy density increases. Therefore, it is necessary to set the thickness of the sidewall portion of the aforementioned casing 20 to an appropriate level. On the other hand, a gold plating layer is formed on the aforementioned casing 20. In this case, the gold plating layer includes, for example, nickel (Ni). The thickness of the aforementioned gold plating layer ranges from approximately 1.5µm to 6.0µm.

[0245] Reference Figure 6 and Figure 23 To ensure rigidity, the cover plate 30 is made of, for example, a metal material. The cover plate 30 seals the opening (or open end) formed at the lower end of the outer casing 20. That is, the cover plate 30 constitutes the lower surface of the cylindrical battery 1. In the cylindrical battery 1 of the present invention, when the cover plate 30 is made of a conductive metal material, it may not be polarized. "Not polarized" means that the cover plate 30 is not electrically connected to the electrode assembly 10. Thus, when the cover plate 30 is not electrically connected to the electrode assembly 10, it does not serve as an anode or cathode terminal. That is, in the present invention, the cover plate 30 does not need to be electrically connected to the electrode assembly 10 and the outer casing 20, and its material does not necessarily need to be a conductive metal.

[0246] When the outer casing 20 of the present invention has a rolled edge portion 21, the cover plate 30 is supported on the lower surface of the rolled edge portion 21 of the outer casing 20. Alternatively, when the outer casing 20 of the present invention has a crimping portion 22, the cover plate 30 is fixed by the crimping portion 22. That is, the upper surface of the cover plate 30 is supported by the rolled edge portion 21, and the outer peripheral surface and lower surface are supported by the crimping portion 22. A sealing gasket G1 is positioned between the cover plate 30 and the crimping portion 22 of the outer casing 20 to ensure the airtightness of the outer casing 20. On the other hand, as described above, the outer casing 20 of the present invention may not have a rolled edge portion 21 and / or a crimping portion 22. In this case, the sealing gasket 90 is positioned between the fixing structure provided on the open side of the outer casing 20 and the cover plate 30 to ensure the airtightness of the outer casing 20.

[0247] Reference Figure 23 and Figure 24 The cover plate 30 also includes a vent 31, which is used to prevent the internal pressure from exceeding a predetermined value due to gas generated inside the housing 20. The preset internal pressure value is approximately 15 to 35 kgf / cm². 2 The aforementioned venting section 31 corresponds to a region in the cover plate 30 that is thinner than the surrounding area. The venting section 31 is structurally weaker than the surrounding area. Therefore, when the cylindrical battery 1 malfunctions and the internal pressure of the casing 20 increases to a certain level, the venting section 31 is broken, releasing the gas generated inside the casing 20. The venting section 31 is formed, for example, by locally reducing the thickness of the casing 20 by noching on one or both sides of the cover plate 30.

[0248] As described later, in one embodiment of the present invention, the cylindrical battery 1 may have a structure with an anode terminal and a cathode terminal at the upper part, thereby making the upper structure more complex than the lower structure. Therefore, in order to smoothly discharge the gas generated inside the casing 20, an exhaust portion 31 is formed on the cover plate 30 constituting the lower surface of the cylindrical battery 1. Figure 23 As shown, the lower end of the cover plate 30 is preferably positioned higher than the lower end of the outer casing 20. In this case, even if the lower end of the outer casing 20 reaches the ground or the bottom surface of the casing used to implement the module or packaging structure, the cover plate 30 will not reach the ground or the bottom surface of the casing used to implement the module or packaging structure. Therefore, it is possible to prevent the phenomenon that the pressure required for the venting section 31 to break due to the weight of the cylindrical battery 1 differs from the design value, thereby ensuring the smooth breaking of the venting section 31.

[0249] On the other hand, the exhaust portion 31 can extend continuously or discontinuously around the central region of the cover plate 30. In this case, from the perspective of easily destroying the exhaust portion 31 by increasing internal pressure, a larger distance from the center of the cover plate 30 to the exhaust portion 31 is more advantageous. This is because, under the same internal pressure, a larger distance from the center of the cover plate 30 to the exhaust portion 31 results in a larger force acting on the exhaust portion 31, making it easier to destroy. Furthermore, from the perspective of the smoothness of gas discharge, a larger distance from the center of the cover plate 30 to the exhaust portion 31 results in a larger area open by exhaust, which is more advantageous. From this viewpoint, in the entire region of the cover plate 30, the exhaust portion 31 extends downwards (with... Figure 23 It is advantageous when the shape protrudes downwards (based on the direction below) and forms around the edge of the central area with a generally flat shape.

[0250] In the present invention Figure 23 and Figure 24 The illustration shows the exhaust portion 31 being formed in a generally circular and continuous manner on the cover plate 30, but the present invention is not limited thereto. The exhaust portion 31 may have a generally elliptical shape formed on the inner side including the center point of the cover plate 30, or other geometric shapes. In addition, the exhaust portion 31 may also be formed discontinuously, rather than continuously.

[0251] Reference Figure 7 The aforementioned current collector (first current collector) 40 is attached to the upper part of the electrode assembly 10. The aforementioned current collector 40 is made of a conductive metal material and is connected to the first uncoated part 11.

[0252] Reference Figure 7 and Figure 8 The current collector 40 is bonded to a bonding surface (bending surface) 102 formed by bending the end of the first uncoated portion 11 in a direction parallel to the current collector 40. The bending direction of the first uncoated portion 11 is the radial direction of the electrode assembly 10. For example, the bending direction of the first uncoated portion 11 is towards the winding center C of the electrode assembly 10. When the first uncoated portion 11 has such a bending shape, the space occupied by the first uncoated portion 11 is reduced, thereby increasing the energy density. In addition, by increasing the bonding area between the first uncoated portion 11 and the current collector 40, the bonding force can be improved and the contact resistance can be reduced.

[0253] Reference Figures 7 to 9 At least a portion of the first uncoated portion 11 and / or the second uncoated portion 12 includes a plurality of segmented pieces divided along the winding direction of the electrode assembly 10 (see reference). Figure 26 and Figure 29(Ref. 11a). In this case, the aforementioned multiple segmented pieces are bent along the radial direction of the electrode assembly 10. The bent multiple segmented pieces overlap to form multiple layers. In this case, the first uncoated portion of the current collector (first current collector) 40 described later (refer to...) Figures 12 to 15 The second uncoated portion of the joint 72 of the current collector (second current collector) 70 and / or the current collector (second current collector) 70 (see reference) Figure 25 This is combined with multiple segments to form a multi-layered region.

[0254] Reference Figures 7 to 9 The first uncoated portion 11 and / or the second uncoated portion 12 bend from the outer periphery of the electrode assembly 10 toward the electrode core side, resulting in segments overlapping into more than 10 sections.

[0255] Regarding the segmented pieces of the first uncoated portion 11 and / or the second uncoated portion 12, when multiple segmented pieces are overlapped by bending from the outer periphery of the electrode assembly 10 toward the core side, the number of overlapping layers of the segmented pieces gradually increases as they move closer to the core side from the outer periphery. The gradually increasing number of overlapping layers of the segmented pieces remains constant when it reaches a certain range.

[0256] The welding target area is defined as a range that approximates the maximum value of the number of overlapping layers of the aforementioned segmented sheets while maintaining a certain range. The number of overlapping layers in the welding target area is, for example, approximately 10 or more. The first current collector 40 and / or the second current collector 70, described later, are welded to the first uncoated portion 11 and / or the second uncoated portion 12 in such a way that they overlap the welding target area by at least 50%. When welding the first current collector 40 and / or the second current collector 70 onto the generally flat bonding surface 102 formed by bending the first uncoated portion 11 and / or the second uncoated portion 12, it is preferable to increase the laser power to ensure sufficient welding strength. When the laser power is increased, the laser penetrates through the overlapping area of ​​the first uncoated portion 11 and penetrates into the interior of the electrode assembly 10, thereby damaging the separation membrane, active material layer, etc. Therefore, to prevent laser penetration, it is preferable to increase the number of overlapping layers of the first uncoated portion 11 to a certain level or higher. To increase the number of overlapping layers of the first uncoated portion 11, it is necessary to increase the height of the segmented sheets. However, when the height of the segmented plate is increased, ripples may occur in the first uncoated portion 11 during the manufacturing process of the first electrode current collector. Therefore, it is preferable to adjust the height of the segmented plate to an appropriate level.

[0257] As described above, based on the radius of the electrode assembly, the length ratio in the radial direction of the segmented sheets with an overlap of 10 or more layers of uncoated portions is designed to be 25% or more. When laser welding is performed on the area of ​​the segmented sheets of uncoated portions with an overlap of 10 or more layers and the current collector 40, even if the laser power is increased, the overlapping parts of the uncoated portions can fully shield the laser, thereby preventing the separation membrane, active material layer, etc. from being damaged by the laser.

[0258] Reference Figure 6 and Figure 7 The aforementioned current collector (first current collector) 40 is attached to the upper part of the electrode assembly 10. Furthermore, the aforementioned current collector 40 is attached to the terminal 50. That is, the aforementioned current collector 40 electrically connects the first uncoated portion 11 of the electrode assembly 10 and the terminal 50. The aforementioned first current collector 40 is made of a conductive metal material.

[0259] Reference Figure 6 and Figure 7 , Figure 8 and Figure 9 The current collector 40 is bonded to a bonding surface (bending surface) 102 formed by bending the end of the first uncoated portion 11 in a direction parallel to the current collector 40. The bending direction of the first uncoated portion 11 is, for example, towards the winding center C, i.e., the core, of the electrode assembly 10. With this bending configuration, the space occupied by the first uncoated portion 11 is reduced, thereby increasing energy density. Furthermore, with this bending configuration, the increased bonding area between the first uncoated portion 11 and the current collector 40 improves bonding strength and reduces resistance.

[0260] Reference Figure 6 and Figure 7 , Figures 12 to 15 The current collector 40 includes an edge portion 41, an uncoated portion joint (first uncoated portion joint) 42, and a terminal joint 43. The edge portion 41 is disposed on the upper part of the electrode assembly 10 and has a generally rim shape with an empty space S formed therein. The accompanying drawings only illustrate the case where the edge portion 41 has a generally circular rim shape, but the present invention is not limited thereto. The edge portion 41 may also have a generally quadrilateral rim shape, a hexagonal rim shape, an octagonal rim shape, or other other rim shapes, different from the illustrated shape.

[0261] The aforementioned uncoated portion joint (first uncoated portion joint) 42 extends inward from the edge portion 41 and joins with the first uncoated portion 11. As described above, the joining of the current collector 40 and the first uncoated portion 11 is preferably performed in such a way that it overlaps with the welding target area by at least approximately 50% within a range that approximately represents the maximum value as the number of overlapping layers of the segmented pieces increases. That is, the uncoated portion joint 42 of the current collector 40 joins with the first uncoated portion 11 in such a way that it overlaps with the welding target area by at least approximately 50%.

[0262] The terminal connection portion 43 is separated from the uncoated portion connection portion 42 and located inside the edge portion 41. The terminal connection portion 43 is joined to the terminal 50 (described later) by welding. To ensure the welding area for joining with the flat portion formed on the bottom surface of the terminal 50, the terminal connection portion 43 has a diameter substantially the same as or larger than the diameter of the flat portion formed on the bottom surface of the terminal 50. The terminal connection portion 43 is located, for example, at approximately the center of the inner space surrounded by the edge portion 41. The terminal connection portion 43 is positioned corresponding to the hole formed in the winding center C of the electrode assembly 10. The terminal connection portion 43 is configured to cover the hole formed in the winding center C of the electrode assembly 10 so that the hole formed in the winding center C of the electrode assembly 10 is not exposed to the outside of the terminal connection portion 43. In this way, when the hole formed in the winding center C of the electrode assembly 10 is blocked, the separation membrane located inside the hole is damaged due to the flow rate of the electrolyte through the hole, thereby preventing the electrode from being exposed. Therefore, the terminal connection portion 43 has a larger diameter or width than the hole formed in the winding center C of the electrode assembly 10.

[0263] The uncoated portion joint 42 and the terminal joint 43 are arranged separately from each other and are electrically connected through the edge portion 41. Thus, in one embodiment of the present invention, the current collector 40 has a structure in which the uncoated portion joint 42 and the terminal joint 43 are not directly connected but are connected through the edge portion 41. This allows for the dispersion of impacts applied to the joint between the uncoated portion joint 42 and the first uncoated portion 11, and the joint between the terminal joint 43 and the terminal 50, in the event of an impact and / or vibration to the cylindrical battery 1. Therefore, the current collector 40 of the present invention can minimize or prevent damage to the welded joint caused by external impacts. The current collector 40 of the present invention has a structure that concentrates stress at the connection between the edge portion 41 and the terminal joint 43 when an external impact is transmitted to the inside of the cylindrical battery 1 through the terminal 50. However, such a connection is not a welded joint for joining components. Therefore, in the present invention, product defects caused by welded joint damage due to external impacts can be effectively prevented.

[0264] The current collector 40 also includes a connecting portion 44 extending inward from the edge portion 41 and connecting to the terminal connection portion 43. The connecting portion 44 has a tapered portion 44a that narrows in width from the inner side of the edge portion 41 along the direction toward the terminal connection portion 43. That is, the tapered portion 44a has a shape where its width widens along the direction toward the edge portion 41 at the connection point between the terminal connection portion 43 and the edge portion 41. The width variation of the tapered portion 44a can be formed continuously or in stages. With the tapered portion 44a, the rigidity of the component at the connection point between the connecting portion 44 and the edge portion 41 can be improved. With the tapered portion 44a, during the manufacturing process of the cylindrical battery 1, the tapered portion 44a can be held by a conveying device and / or an operator, thereby facilitating easy and safe transport of the current collector 40 and / or the assembly of the current collector 40 and the electrode assembly 10. That is, when the tapered portion 44a is provided, a component that is welded to other components, such as the uncoated portion joint portion 42 or the terminal joint portion 43, is maintained, thereby preventing possible product defects.

[0265] On the other hand, multiple first uncoated portion joints 42 are provided. When multiple first uncoated portion joints 42 are provided, they are arranged radially, cross-shaped, or combined, for example, based on the center portion of the terminal joint 43. In the accompanying drawings of the present invention, only cases with three and four first uncoated portion joints 42 are illustrated, but the present invention is not limited thereto. The number of first uncoated portion joints 42 varies depending on factors such as the required resistance level in the cylindrical battery 1 and the aperture ratio of the first current collector 40. Multiple first uncoated portion joints 42 are regularly arranged along the extending direction of the edge portion 41. For example, multiple first uncoated portion joints 42 are arranged at substantially the same interval along the extending direction of the edge portion 41. The extension length of each of the multiple first uncoated portion joints 42 is substantially the same. The first uncoated portion joints 42 are joined to the first uncoated portion 11 by welding.

[0266] The terminal joint 43 is arranged such that it is surrounded by a plurality of the aforementioned first uncoated joints 42. The terminal joint 43 is joined to the terminal 50 by welding. The connecting portion 44 is located between a pair of adjacent first uncoated joints 42. In this case, the distance from the connecting portion 44 along the extending direction of the edge portion 41 to either of the pair of first uncoated joints 42 is substantially the same as the distance from the connecting portion 44 along the extending direction of the edge portion 41 to the other of the pair of first uncoated joints 42. The cross-sectional areas of each of the plurality of first uncoated joints 42 are substantially the same. The width and thickness of each of the plurality of first uncoated joints 42 are substantially the same.

[0267] The device includes multiple connecting portions 44. The number of connecting portions 44 is determined by considering the required resistance level in the cylindrical battery 1, the aperture ratio of the first current collector 40, etc. Multiple connecting portions 44 are respectively disposed between a pair of adjacent first uncoated portion joints 42. The multiple connecting portions 44 are regularly arranged relative to each other along the extending direction of the edge portion 41. For example, the multiple connecting portions 44 are arranged at substantially the same interval along the extending direction of the edge portion 41. On the other hand, the distance from each of the multiple connecting portions 44 to one of the adjacent pair of first uncoated portion joints 42 along the extending direction of the edge portion 41 is substantially the same as the distance to the other first uncoated portion joint 42.

[0268] As described above, when multiple first uncoated portion joints 42 and / or connecting portions 44 are provided, when the distance between the first uncoated portion joints 42 and / or the distance between the connecting portions 44 and / or the distance between the first uncoated portion joints 42 and the connecting portions 44 is formed to be approximately constant, the flow of current from the first uncoated portion joints 42 toward the connecting portions 44 or from the connecting portions 44 toward the first uncoated portion joints 42 can be smoothly formed.

[0269] The current collector 40 and the first uncoated portion 11 are joined by welding. In this case, laser welding, ultrasonic welding, spot welding, etc., are used, for example.

[0270] Reference Figures 16 to 20The aforementioned connecting portion 44 includes current-cutting portions N, G, and T formed by partially reducing the cross-sectional area of ​​the connecting portion 44. The reduction in the cross-sectional area of ​​the connecting portion 44 in the region where the current-cutting portion is formed is achieved, for example, by reducing the width and / or thickness of the connecting portion 44. With the aforementioned current-cutting portion, the resistance in the region where the current-cutting portion is formed increases, thereby causing damage in the current-cutting portion when an overcurrent occurs, thus rapidly cutting off the current. Multiple current-cutting portions are formed along the length direction of the connecting portion. When multiple connecting portions 44 are provided, the current-cutting portion is provided in at least one of the multiple connecting portions 44. The aforementioned current-cutting portion includes, for example, at least one of a recess, a groove, and a through hole.

[0271] When the connecting portion 44 has a tapered portion 44a, the current cutting-off portion is positioned closer to the tapered portion 44a than the terminal connection portion 43 side. Relatively more heat is generated at the narrowest part of the tapered portion 44a, thereby enabling the current cutting-off portion near the tapered portion 44a to quickly cut off the overcurrent.

[0272] On the other hand, to prevent foreign matter such as weld slag from entering the interior of the electrode assembly 10 in the event of damage, it is preferable to form the current-cutting portion in a region corresponding to the welding target area of ​​the electrode assembly 10. This is because, in this region, the number of overlapping layers of the segments of the first uncoated portion 11 remains at its maximum, thereby the overlapping segments function as a mask. The current-cutting portion is formed, for example, at a location approximately 40% to 90% of the distance from the core of the electrode assembly 10 along the radial direction, based on the radius of the electrode assembly. Preferably, the current-cutting portion is located approximately at the center between the core and the outermost edge of the electrode assembly 10.

[0273] Reference Figure 16 and Figure 17 The aforementioned current-cutting portion includes a recess N formed on at least one side of the connecting portion 44. The recess N has a shape in which its width gradually narrows as it moves closer to the inner side from the surface of the connecting portion 44. The recess N is formed on the side surface and / or the upper surface and / or the lower surface of the connecting portion 44. Figure 17 As shown in the figure, when multiple connecting portions 44 are provided, at least one connecting portion is formed among the multiple connecting portions 44.

[0274] Reference Figure 18 and Figure 19 The aforementioned current-cutting portion includes a groove G formed on at least one side of the connecting portion 44. The groove G is formed on the side and / or upper and / or lower surface of the connecting portion 44. Although not shown, in the case of multiple connecting portions 44, the groove G is formed on at least one of the multiple connecting portions 44.

[0275] Reference Figure 20 The aforementioned current-cutting portion includes a through hole T formed on at least one side of the connecting portion 44. The through hole T has a shape that extends between the upper and lower surfaces of the connecting portion 44 and / or extends through the side surface of the connecting portion 44. Although not shown, when there are multiple connecting portions 44, the through hole T is formed in at least one of the multiple connecting portions 44.

[0276] Although not illustrated, when there are multiple connecting portions 44, and two or more of these connecting portions 44 have current cutting portions, the multiple current cutting portions may all have substantially the same shape, or they may have different shapes from each other. For example, the multiple current cutting portions may include at least two of a notch N, a groove G, and a through hole T.

[0277] Reference Figure 21 A strip 46 is attached to the aforementioned current-cutting portion. The strip 46 surrounds the connecting portion 44 in the area where the current-cutting portion is formed. The strip 46 is made of various materials, such as polyimide (PI), which is not easily deformed by heat. However, the material of the strip 46 of the present invention is not limited to this.

[0278] When the aforementioned strip 46 is used, heat dissipation is difficult when the current-cutting section generates heat. Therefore, the temperature in the current-cutting section rises rapidly, causing it to break quickly and interrupt the overcurrent. Furthermore, using the strip 46 prevents foreign matter such as molten metal from splashing onto other components and causing damage when the current-cutting section breaks.

[0279] The ratio of the cross-sectional area of ​​the connecting portion 44 in the region where the current-cutting portion is formed to the cross-sectional area of ​​the connecting portion 44 in the region where the current-cutting portion is not formed is approximately in the range of 0.6 to 0.9. For example, when the current-cutting portion is provided in a form that maintains the thickness of the connecting portion 44 while reducing its width, the ratio of the width of the connecting portion 44 in the region where the current-cutting portion is formed to the width of the connecting portion 44 in the region where the current-cutting portion is not formed is approximately in the range of 0.6 to 0.9. This is also the case when the current-cutting portion is provided in a form that maintains the width of the connecting portion 44 while reducing its thickness. If the cross-sectional area is excessively reduced due to the current-cutting portion, the resistance of the cylindrical battery 1 becomes too high, and if the reduction in cross-sectional area is not significant, it is difficult to achieve the purpose of cutting off the overcurrent.

[0280] On another side, the number of the aforementioned connecting portions 44 is one or two. This is to quickly cut off overcurrent. If the number of the aforementioned connecting portions 44 is too large, the current flow will be dispersed, making it difficult to perform the fuse function properly. Considering the viewpoint of ensuring the rigidity of the aforementioned current collector 40, the number of the aforementioned connecting portions 44 is two. On yet another side, the ratio of the cross-sectional area of ​​the aforementioned connecting portion 44 to the cross-sectional area of ​​the aforementioned uncoated portion joint 42 is approximately in the range of 0.2 to 1.0. For example, when the thickness of the aforementioned connecting portion 44 and the uncoated portion joint 42 is substantially the same, the ratio of the width of the aforementioned connecting portion 44 to the width of the aforementioned uncoated portion joint 42 is approximately in the range of 0.2 to 1.0. If the cross-sectional area of ​​the aforementioned connecting portion 44 is too large, it will be difficult to achieve the purpose of cutting off overcurrent; if the cross-sectional area of ​​the connecting portion 44 is too small, the overall resistance value of the cylindrical battery 1 will be too large.

[0281] In another aspect of the invention, the aperture ratio of the current collector 40 is defined as the ratio of the area of ​​the current collector 40 that does not contact the upper surface of the electrode assembly 10 to the area of ​​a circle with the outer diameter of the electrode assembly 10 as its diameter. The aperture ratio is calculated using the following formula.

[0282] Opening ratio %

[0283] =1 - (area of ​​contact between the current collector and the upper surface of the electrode assembly) / (area of ​​a circle with the outer diameter of the electrode assembly as its diameter)

[0284] = (Area of ​​the current collector not in contact with the upper surface of the electrode assembly) / (Area of ​​a circle with the outer diameter of the electrode assembly as its diameter)

[0285] The aperture ratio of the current collector 40 is, for example, approximately 20% or more and less than 100%, preferably approximately 60% or more and less than 100%. Figure 12 Taking the case where the current collector 40 is placed on the electrode assembly 10 for bonding as an example, the areas where the current collector 40 contacts the electrode assembly 10 are the edge portion 41, the uncoated portion bonding portion 42, and the connecting portion 44. That is, the ratio of the area of ​​the current collector 40 in contact with the electrode assembly 10 to the area of ​​a circle with a diameter having the same length as the outer diameter of the electrode assembly 10 is approximately 80% or less, preferably approximately 70% or less. When the opening ratio of the current collector 40 is within the above range, the impregnation of the electrolyte can be carried out smoothly. That is, there is a gap around the terminal bonding portion 43 located at the center of the current collector 40, through which the electrolyte spreads radially, moves into the opening space, and then permeates to the electrode assembly 10 side.

[0286] Reference Figure 22 The aforementioned current collector (first current collector) 40 in Figures 5 to 10Based on the illustrated embodiment, a bridging portion 45 is further included to connect at least one of the following: adjacent first uncoated portion joints 42, adjacent first uncoated portion joints 42 and connecting portions 44, and adjacent connecting portions 44. The bridging portion 45 is disposed closer to the inside than the edge portion 41. The current collector 40 has an impregnation hole 40a formed between the edge portion 41 and the bridging portion 45. The impregnation hole 40a, for example, has a generally slit shape extending along the extending direction of the edge portion 41. The impregnation hole 40a increases the ratio of empty space S formed inside the edge portion 41, facilitating the circulation of electrolyte injected into the housing 20, thereby improving impregnation performance.

[0287] Reference Figures 5 to 7 The terminal 50 is made of a conductive metal. For example, aluminum (Al) can be used as the material for the terminal 50. When the terminal 50 is made of aluminum, it is easier to perform the riveting process described later, and 10-series aluminum, which has relatively low electrical resistance, is used. The terminal 50 is electrically connected, for example, to the first uncoated portion 11 of the electrode assembly 10 via the upper surface of the housing 20, i.e., the surface opposite the opening of the housing 20 (the surface parallel to the XY plane). In this case, the terminal 50 has a first polarity. Therefore, the terminal 50 serves as the first electrode terminal in the cylindrical battery 1 of the present invention. Thus, when the terminal 50 has a first polarity, the terminal 50 is electrically insulated from the housing 20, which has a second polarity. Electrical insulation between the terminal 50 and the housing 20 is achieved in various ways. For example, insulation can be achieved by placing an insulating pad G2 between the terminal 50 and the housing 20. Alternatively, insulation can be achieved by forming an insulating coating on a portion of the terminal 50. Alternatively, the terminal 50 can be structurally secured so that it cannot contact the housing 20. Alternatively, multiple methods described above can be applied together.

[0288] The terminal 50 includes a terminal protrusion 51 and a terminal insertion portion 52. The terminal insertion portion 52 includes an electrical connection portion 42a and a frame portion 42b. The terminal protrusion 51 protrudes to the outside of the housing 20. The terminal protrusion 51 is located approximately at the center of the closing portion of the housing 20. The maximum width of the terminal protrusion 51 is greater than the maximum width of the hole formed in the housing 20 for inserting the terminal 50. The terminal insertion portion 52 penetrates approximately at the center of the closing portion of the housing 20, and the electrical connection portion 52a of the terminal insertion portion 52 is electrically connected to the first uncoated portion 11. When the cylindrical battery 1 of the present invention is equipped with an insulator 60, the terminal insertion portion 52 is surrounded by the insulator 60 so that its side surface is not exposed. The frame portion 52b of the terminal insertion portion 52 is formed around the electrical connection portion 52a and is riveted to the inner surface of the closing portion of the housing 20. That is, the frame portion 52b of the terminal insertion portion 52 has a shape that is twisted toward the inner surface of the closing portion of the housing 20. Therefore, after the riveting process is performed to fix the terminal 50, the maximum width of the terminal insertion portion 52 is greater than the maximum width of the hole formed in the housing 20 for the terminal insertion portion 52 to pass through.

[0289] Reference Figures 5 to 7 , Figures 10 to 12 The electrical connection portion 52a of the aforementioned terminal insertion portion 52 is coupled to the terminal connection portion 43 of the current collector (first current collector) 40. The electrical connection portion 52a of the aforementioned terminal insertion portion 52 has, for example, a generally cylindrical shape. However, the shape of the electrical connection portion 52a of the aforementioned terminal insertion portion 52 is not limited to this. The electrical connection portion 52a of the aforementioned terminal insertion portion 52 may have various shapes, such as a cylindrical shape, a square prism shape, a hexagonal prism shape, or an octagonal prism shape with an elliptical cross-section. At least a portion of the bottom surface of the electrical connection portion 52a of the aforementioned terminal insertion portion 52 is substantially flat.

[0290] Reference Figure 7 , Figure 9 and Figure 10 The connection between the bottom surface of the central region of the terminal insertion portion 52 and the current collector (first current collector) 40 is performed, for example, by laser welding, spot welding or ultrasonic welding.

[0291] The aforementioned welding is performed by irradiating a laser through a hole formed in the winding center C of the electrode assembly 10 or by inserting a tool for ultrasonic welding or spot welding, thereby forming a weld bead on the side facing the current collector 40 (the side facing the hole formed in the winding center C of the electrode assembly 10). A lead tube (not shown) for welding can be inserted into the hole formed in the winding center C. When welding is performed with the lead tube inserted, the possibility of damage to the separation film constituting the inner wall surface of the hole formed in the winding center C can be reduced.

[0292] The welding pattern drawn by the weld bead W formed on one side of the terminal joint portion 43 of the current collector 40 has a shape that surrounds the center portion P of the bottom surface of the electrical connection portion 52a of the terminal insertion portion 52. The welding pattern is, for example, approximately circular, but it can also be approximately elliptical or approximately quadrilateral, hexagonal, octagonal, or other polygonal shapes. The welding pattern formed by the weld bead W is continuous (see...). Figure 10 ) or discontinuous (refer to) Figure 11 The weld pattern formed by the above weld bead W is exemplified by circles, ellipses, polygons, etc., but does not represent geometrically complete circles, ellipses, polygons, etc.

[0293] On the other hand, the diameter of the flat portion on the bottom surface of the electrical connection portion 52a formed in the terminal insertion portion 52 is determined taking into account the welding strength with the current collector 40. The tensile force of the weld between the flat portion and the current collector (first current collector) 40 is at least approximately 2 kgf or more, or 3 kgf or more, or 4 kgf or more, or 5 kgf or more, or 6 kgf or more, or 7 kgf or more, or 8 kgf or more, or 9 kgf or more, or 10 kgf or more. Preferably, the tensile force of the weld is increased to the maximum within the allowable range when the optimal welding method is selected.

[0294] To meet the tensile strength requirements of the weld, the diameter (or maximum width) of the weld pattern formed on the aforementioned flat portion is approximately 2 mm. The diameter of the weld pattern is determined by transforming the area S of the weld bead W appearing on the surface of the weld area into the area (πr) of a circle. 2 The converted diameter of the circle at time (2) S / π 0.5 It is defined by )

[0295] The flat portion formed on the bottom surface of the electrical connection portion 52a of the terminal insertion portion 52 corresponds to the solderable area. The diameter of the solderable area is approximately 3 mm to 14 mm. When the diameter of the solderable area is approximately less than 3 mm, it is difficult to ensure a solder pattern with a diameter (converted diameter) of 2 mm or more. In particular, when a solder pattern is formed using laser welding, it is difficult to ensure a solder pattern with a diameter of 2 mm or more due to the gap in the laser beam. When the diameter of the solderable area is approximately greater than 14 mm, the diameter of the terminal protrusion portion 51 of the terminal 50 can only reach that or more, thereby making it difficult to sufficiently ensure the area of ​​the outer surface 20a of the housing 20 having a polarity opposite to that of the terminal 50.

[0296] Considering the diameter conditions of the weld pattern and the weldable area mentioned above, in order to ensure a weld tensile strength of at least approximately 5 kgf, the ratio of the area of ​​the weld pattern to the area of ​​the required weldable area is preferably approximately 2.04% (π1). 2 / π7 2 ) to 44.4% (π1 2 / π1.5 2 ).

[0297] As an example, when the flat portion of the bottom surface of the electrical connection portion 52a formed in the terminal insertion portion 52 and the current collector 40 are welded by laser, and the weld bead W is drawn as a continuous or discontinuous line in the form of a generally arcuate pattern, the diameter of the arcuate weld pattern is approximately 2 mm or more, preferably approximately 4 mm or more. When the diameter of the arcuate weld pattern meets this condition, the tensile force of the weld is increased to approximately 5 kgf or more, thereby ensuring sufficient weld strength.

[0298] As another example, when the flat portion formed on the bottom surface of the electrical connection portion 52a of the terminal insertion portion 52 and the current collector 40 are welded by ultrasonic waves in a circular pattern, the diameter of the circular welding pattern is preferably approximately 2 mm or more. When the diameter of the circular welding pattern meets this condition, the tensile force of the welded portion is increased to approximately 2 kgf or more to ensure sufficient weld strength.

[0299] The diameter of the flat portion formed on the bottom surface of the terminal 50, which corresponds to the weldable area, can be adjusted within a range of approximately 3 mm to 14 mm. If the radius of the flat portion is approximately less than 3 mm, it is difficult to form a weld pattern with a diameter of approximately 2 mm or more using laser welding tools, ultrasonic welding tools, or the like.

[0300] On the other hand, in one embodiment of the present invention, the cylindrical battery 1 has a structure in which the bottom surface of the electrical connection portion 52a of the terminal insertion portion 52 described above is welded to the current collector 40 for bonding, thereby maximizing the bonding area between the current collector 4 and the terminal 50. That is, at least a portion of the bottom surface of the electrical connection portion 52a is formed into a flat shape, thereby maximizing the bonding area between the terminal 50 and the current collector 40. Therefore, in one embodiment of the present invention, when a large amount of current flows during rapid charging, the cylindrical battery 1 can ensure smooth current flow at the bonding portion between the current collector 40 and the terminal 50, thereby shortening the charging time and reducing heat generation.

[0301] The aforementioned insulating pad G2 includes a protruding pad portion GA and a pad insertion portion GB. The protruding pad portion GA is located between the protruding terminal portion 51 of the terminal 50 and the housing 20. The protruding pad portion GA extends further than the protruding terminal portion 51, thus allowing it to be exposed to the outside of the protruding terminal portion 51 when viewed from above. The pad insertion portion GB is located between the terminal insertion portion 52 of the terminal 50 and the housing 20. During the reveting of the frame portion 52b of the terminal insertion portion 52, the pad insertion portion GB deforms and adheres tightly to the inner side of the closing portion of the housing 20. The insulating pad G2 is, for example, made of a resin material possessing insulating and elastic properties.

[0302] Reference Figure 6 and Figure 7 , Figure 12 The insulator 60 is disposed between the current collector (first current collector) 40 and the inner surface of the housing 20. The insulator 60 prevents contact between the current collector 40 and the housing 20. The insulator 60 may also be located between the upper end of the outer peripheral surface of the electrode assembly 10 and the inner surface of the housing 20. That is, the insulator 60 may also be located between the first uncoated portion 11 and the inner surface of the sidewall portion of the housing 20. This is to prevent contact between the first uncoated portion 11, which extends toward the closing portion of the housing 20, and the inner peripheral surface of the housing 20.

[0303] In the case where the cylindrical battery 1 of the present invention includes an insulator 60, the terminal 50 is connected to the current collector 40 through the insulator 60. Thus, for the terminal 50 to pass through, the insulator 60 has a hole formed approximately at its center. The hole formed in the insulator 60 is formed at a position corresponding to the terminal connection portion 43 of the current collector 40. The hole formed in the insulator 60 is formed at a position corresponding to the hole formed in the winding center C of the electrode assembly 10. The hole formed in the insulator 60 is formed at a position corresponding to the electrical connection portion 52a provided in the terminal insertion portion 52 of the terminal 50. Therefore, the electrical connection portion 52a of the terminal insertion portion 52 is connected to the terminal connection portion 43 of the current collector 40 through the hole formed in the insulator 60.

[0304] On the other hand, if the weld joint between the terminal 50 and the first current collector 40 is located inside the hole formed in the winding center C of the electrode assembly 10, it may cause damage to the electrode assembly 10. To prevent this, the lower end of the terminal 50, which is coupled to the terminal joint 43, is located at a position that is substantially at the same height as or higher than the lower surface of the insulator 60. In this case, the weld joint between the terminal 50 and the first current collector 40 is located outside the hole formed in the winding center C of the electrode assembly 10.

[0305] With this in mind, the thickness of the insulator 60 is substantially the same as or greater than the distance from the inner surface of the closing portion of the housing 20 to the flat portion located at the lower end of the terminal 50. On the other hand, the insulator 60 fills the space between the inner surface of the closing portion of the housing 20 and the current collector 40 along the height direction (parallel to the Z-axis), and has a thickness corresponding to the distance between the inner surface of the closing portion of the housing 20 and the current collector 40, to prevent the generation of space for vertical movement of the electrode assembly 10. In another aspect, the upper surface of the insulator 60 contacts the inner surface of the closing portion of the housing 20, and the lower surface of the insulator 60 contacts the upper surface of the current collector 40.

[0306] Reference Figure 23 and Figure 25 The aforementioned current collector (second current collector) 70 is bonded to the lower part of the electrode assembly 10. The current collector 70 is made of a conductive metal material and is bonded to the second uncoated portion 12. Furthermore, the current collector 70 is electrically connected to the housing 20. The current collector 70 electrically connects the second uncoated portion 12 to the housing 20. At least a portion of the area surrounding the edge of the current collector 70 is fixed between the underside (mounting surface) of the rolled edge portion 21 of the housing 20 and the sealing gasket G1. In this case, the current collector 70 is welded to the mounting surface formed by the rolled edge portion 21 of the housing 20. The sealing gasket G1 is disposed within the crimp portion 22, between the housing 20 and the cover plate 30.

[0307] The aforementioned current collector 70 includes a second current collector hole 70a formed in a region corresponding to the hole formed in the take-up center C of the electrode assembly 10. The take-up center hole and the second current collector hole 70a, which communicate with each other, serve as channels for inserting a welding rod or irradiating a laser beam for welding between the terminal 50 and the terminal joint 43 of the first current collector 40. The second current collector hole 70a is formed with the same diameter as or larger than the hole formed in the take-up center C of the electrode assembly 10, so as not to obstruct the hole formed in the take-up center C of the electrode assembly 10. If the diameter of the second current collector hole 70a is too small compared to the diameter of the hole formed in the take-up center C, the hole formed in the take-up center C is obstructed, resulting in decreased injection performance and difficulty in adequately ensuring space for inserting welding devices or irradiating the laser.

[0308] Unlike the embodiments described above, according to another embodiment of the present invention, the diameter of the second current collector hole 70a is smaller than the diameter of the hole formed in the winding center C of the core of the electrode assembly 10. For example, when the diameter of the hole formed in the winding center C is set to R3, the diameter of the second current collector hole 70a is 0.5. R3 or higher and less than R3, preferably 0.7 R3 or higher and less than R3.

[0309] Under normal circumstances, when the opening occurs, gas is discharged from the winding center portion, and under strong pressure, the separation film or uncoated portion located on the winding center side is exposed from the lower surface of the electrode assembly 10. At this time, when the diameter of the second current collector hole 70a is smaller than the diameter of the hole provided in the core of the electrode assembly 10, it is possible to prevent the separation film or uncoated portion located on the winding center side from detaching from the lower surface of the electrode assembly 10. However, if the diameter of the second current collector hole 70a is too small, the electrolyte injection performance decreases, and sufficient space needs to be ensured for soldering between the second current collector 70 and the terminal 50. Therefore, the diameter of the second current collector hole 70a is preferably 0.5 mm. R3 or higher, preferably 0.7 R3 and above.

[0310] The second current collector 70 includes a second uncoated portion joining portion 72 that is coupled to the second uncoated portion 12 and a housing joining portion 73 that is coupled to the housing 20. The second current collector 70 also includes a support portion 71. The second uncoated portion 12 and the second uncoated portion joining portion 72 are joined together by welding. The housing 20 and the housing joining portion 73 are joined together by welding. The housing joining portion 73 is electrically coupled to the lower surface of the rolled edge portion 21.

[0311] The aforementioned support portion 71 is disposed at the lower part of the electrode assembly 10. With the support portion 71, the second uncoated portion bonding portion 72 extends from the support portion 71 along approximately the radial direction of the electrode assembly 10 and bonds to the second uncoated portion 12. Furthermore, the aforementioned housing bonding portion 73 extends from the support portion 71 along approximately the radial direction of the electrode assembly 10 and bonds to the inner surface of the housing 20. The second uncoated portion bonding portion 72 and the housing bonding portion 73 are not directly connected to each other, but are indirectly connected through the support portion 71. In this case, the possibility of damage to the bonding portions of the second current collector 70 and the electrode assembly 10 and the second current collector 70 and the housing 20 is minimized when an external impact is applied to the cylindrical battery 1. However, the second current collector 70 of the present invention is not limited to this structure where the second uncoated portion bonding portion 72 and the housing bonding portion 73 are indirectly connected. For example, the second current collector 70 may also have a structure that does not include the support portion 71 that indirectly connects the second uncoated portion joint 72 and the housing joint 73, and / or a structure in which the second uncoated portion joint 72 and the housing joint 73 are directly connected to each other.

[0312] On the other hand, the aforementioned second uncoated portion joint 72 and support portion 71 are joined to the second uncoated portion 12. When the outer casing 20 forms a rolled edge portion 21, the aforementioned support portion 71 and second uncoated portion joint 72 are positioned higher than the rolled edge portion 21.

[0313] The device includes multiple second uncoated portion joints 72. When multiple second uncoated portion joints 72 are included, each second uncoated portion joint 72 extends radially from the support portion 71 of the second current collector 70 toward the sidewall of the housing 20. The multiple second uncoated portion joints 72 are arranged separately from each other along the periphery of the support portion 71.

[0314] The device includes multiple housing connection portions 73. In this case, the multiple housing connection portions 73 have a shape that extends radially from the center of the second current collector 70 toward the sidewall of the housing 20. Thus, an electrical connection is formed between the second current collector 70 and the housing 20 at multiple locations. This achieves connection for electrical connection at multiple locations, thereby maximizing the connection area and minimizing resistance. The multiple housing connection portions 73 are arranged separately from each other along the periphery of the support portion 71. At least one housing connection portion 73 is arranged between adjacent second uncoated portion connection portions 72. The multiple housing connection portions 73 are, for example, connected to the rolled edge portion 21 on the inner surface of the housing 20. The housing connection portions 73 are specifically connected to the lower surface of the rolled edge portion 21.

[0315] The aforementioned housing connection portion 73 includes a contact portion 73a that is attached to the inner side surface of the housing 20 and an extension portion 73b that connects the support portion 71 and the contact portion 73a.

[0316] The aforementioned contact portion 73a is bonded to the inner surface of the housing 20. When the housing 20 has a rolled edge portion 21, the contact portion 73a is bonded to the rolled edge portion 21 as described above. More specifically, the contact portion 73a is electrically bonded to a flat portion provided on the lower surface of the rolled edge portion 21 formed on the housing 20, and is located between the lower surface of the rolled edge portion 21 and the sealing gasket G1. In this case, for stable contact and bonding, the contact portion 73a has a shape in which the rolled edge portion 21 extends along the circumferential direction of the housing 20 for a predetermined length.

[0317] Reference Figure 23 and Figure 25 , Figure 8 and Figure 9The current collector 70 is bonded to the joint surface formed by bending the end of the second uncoated portion 12 in a direction parallel to the current collector 70. The bending direction of the second uncoated portion 12 is the radial direction of the electrode assembly 10, for example, towards the winding center C of the electrode assembly 10. When the second uncoated portion 12 has such a bending shape, the space occupied by the second uncoated portion 12 is reduced, thereby increasing the energy density. In addition, the bonding force between the second uncoated portion 12 and the current collector 70 can be improved, and the contact resistance can be reduced. Similar to the case of the first uncoated portion joint 42 of the first current collector 40, in the case of the second uncoated portion joint 72 of the second current collector 70, it is bonded to the second uncoated portion 12 such that the number of overlapping layers formed by bending the segmented pieces of the second uncoated portion 12 is maintained within a certain range, that is, the welding target area overlaps by at least approximately 50%.

[0318] On the other hand, refer to Figure 7 , Figure 23 and Figure 25 The distance from the center of the first current collector 40 to the outermost part of the edge portion 41 (the outer diameter of the first current collector 40) is longer than the distance from the center of the second current collector 70 to the outermost part of the second uncoated portion joint 72 (the outer diameter of the second current collector 70). In the case of the first current collector 40, it can have a diameter close to the inner diameter of the housing 20. The outer diameter of the first current collector 40 relative to the inner diameter of the housing 20 is approximately 33% to 98.5% of its outer diameter. The minimum value of the outer diameter of the first current collector 40 is a value used to prevent excessive increase in resistance. The maximum value of the outer diameter of the first current collector 40 is obtained taking into account tolerances such as those that may occur during the manufacturing of the current collector 40, assembly tolerances that may occur when the electrode assembly 10 and the first current collector 40 are combined, tolerances that may occur during the manufacturing of the housing 20, and tolerances at possible positions when the combined electrode assembly 10 and the first current collector 40 are inserted into the housing 20. In this invention, when the insulator 60 is used and the insulator 60 has a structure that covers the upper end of the outer peripheral surface of the electrode assembly 10, the space for inserting the insulator 60 also needs to be considered. Therefore, the ratio of the outer diameter of the first current collector 40 to the inner diameter of the housing 20 will be less than the maximum value mentioned above. However, the outer diameter of the first current collector 40 is limited to a level slightly smaller than the inner diameter of the housing 20 by taking into account such tolerances. In the case of the second current collector 70, its diameter is further limited to avoid gaps generated during the sizing process. In order to avoid such a gap, the distance from the center of the second current collector 70 to the outermost part of the second uncoated part joint 72 is less than or equal to half the inner diameter in the area where the rolled edge 21 of the housing 20 is formed.

[0319] On the other hand, the length L1 of the welded portion connecting the first uncoated portion 42 and the first uncoated portion 11 of the first current collector 40, extending along the radial direction of the electrode assembly 10, is longer than the length L2 of the welded portion connecting the second uncoated portion 72 and the second uncoated portion 12 of the second current collector 70, extending along the radial direction of the electrode assembly 10. For example, if the first current collector 40 is an aluminum anode current collector and the second current collector 70 is a copper cathode current collector, when the length L1 is longer than the length L2, the welded portion area of ​​the anode current collector, which has lower conductivity, is relatively increased, thereby achieving a balance in the current flow in the anode and cathode current collectors. Here, the extension length of the welded portion connecting the current collectors 40, 70 and the uncoated portions 11, 12 refers to the extension length of the weld bead formed by welding.

[0320] Taking the core of the electrode assembly 10 as a reference, the distance to the starting point of the weld joint where the first uncoated portion 42 and the first uncoated portion 11 of the first current collector 40 are joined is substantially the same as the distance to the starting point of the weld joint where the second uncoated portion 72 and the second uncoated portion 12 are joined. Here, "substantially the same" means that the two distances are identical to each other or, for example, have a deviation of approximately 5% or less.

[0321] In another aspect of the invention, the ratio of the area of ​​the current collector (second current collector) 70 that does not contact the lower surface of the electrode assembly 10 to the area of ​​a circle with the outer diameter of the electrode assembly 10 is defined as the aperture ratio of the current collector 70. The aperture ratio is calculated using the following formula.

[0322] Opening ratio %

[0323] =1 - (area of ​​contact between the current collector and the upper surface of the electrode assembly) / (area of ​​a circle with the outer diameter of the electrode assembly as its diameter)

[0324] = (Area of ​​the current collector not in contact with the upper surface of the electrode assembly) / (Area of ​​a circle with the outer diameter of the electrode assembly as its diameter)

[0325] The aperture ratio of the current collector 70 is, for example, approximately 30% or more and less than 100%, preferably approximately 60% or more and less than 100%. Figure 25As illustrated, taking the case where the current collector 40 is placed on the electrode assembly 10 as an example, the area where the current collector 40 contacts the electrode assembly 10 is the support portion 71 and the uncoated portion joint portion (second uncoated portion joint portion) 72. That is, the ratio of the area where the current collector 70 contacts the electrode assembly 10 to the area of ​​a circle having a diameter with the same length as the outer diameter of the electrode assembly 10 is approximately 70% or less, preferably approximately 40% or less. When the opening ratio of the current collector 70 is within the above range, when electrolyte is injected, the electrolyte smoothly penetrates into the interior of the electrode assembly 10 through the area not blocked by the current collector 70. That is, when the opening ratio of the current collector 70 is within the above range, the electrolyte penetrates into the electrode assembly 10 through the hole provided in the winding center C formed in the electrode assembly 10. In particular, there are fine gaps between the overlapping surfaces and the spacing between the segments 11a, so the electrolyte smoothly penetrates into the electrode assembly 10 through the capillary phenomenon caused by the gaps.

[0326] Reference Figures 26 to 29 The structure of the electrode assembly 10 described above will be explained in more detail below. The following description uses the first electrode of the first electrode and the second electrode described above as examples, but the same structure of the first electrode is also applied to the second electrode.

[0327] Reference Figures 26 to 29 The first electrode 110 includes a sheet-shaped first electrode current collector 111 made of conductive aluminum foil, a first active material layer 112 formed on at least one side of the first electrode current collector 111, and a first uncoated portion 11 formed at the long side end of the first electrode current collector 111 where no active material is coated.

[0328] Preferably, the first uncoated portion 11 includes a plurality of segmented pieces 11a for etched groove processing. The plurality of segmented pieces 11a constitute a plurality of groups, and the height (length in the Z direction) and / or width (length in the X direction) and / or spacing of the segmented pieces 11a belonging to each group are substantially the same. The number of segmented pieces 11a belonging to each group may be increased or decreased compared to the number shown in the figure. The segmented pieces 11a have a shape that combines at least one straight line and / or at least one curve into a geometric figure. Preferably, the segmented pieces 11a are trapezoidal, but can be deformed into quadrilaterals, parallelograms, semicircles, or semi-ellipses, etc.

[0329] Preferably, the height of the segmented piece 11a increases progressively from the core side toward the outer periphery along a direction parallel to the winding direction of the electrode assembly 10. Furthermore, the uncoated portion 11-1 on the core side adjacent to the core side of the electrode assembly 10 may not include the segmented piece 11a, and the height of the uncoated portion 11-1 on the core side is lower than that of other uncoated portions. Additionally, the uncoated portion 11-2 on the outer periphery side adjacent to the outer periphery side of the electrode assembly 10 does not include the segmented piece 11a, and the height of the uncoated portion 11-2 on the outer periphery side is lower than that of other uncoated portions.

[0330] Optionally, the first electrode 110 includes an insulating coating E covering the boundary between the active material layer 112 and the first uncoated portion 11. The insulating coating E comprises an insulating polymer resin and optionally includes an inorganic filler. The insulating coating E prevents the end of the active material layer 112 from contacting an active material layer of opposite polarity through the separation membrane and structurally supports the bending of the segmented sheet 11a. Therefore, when the first electrode 110 is wound to form the electrode assembly 10, at least a portion of the insulating coating E is preferably exposed to the outside from the separation membrane.

[0331] Reference Figure 26 and Figure 27 The aforementioned electrode assembly 10 is constructed by means of... Figure 2 The membrane is manufactured using the winding process described herein. For ease of explanation, the protruding structures of the uncoated portions 11 and 12 extending outward from the separation membrane are shown in detail, while the diagrams of the winding structures of the first electrode, the second electrode, and the separation membrane are omitted. The first uncoated portion 11, protruding upward, extends from the first electrode, and the second uncoated portion 12, protruding downward, extends from the second electrode.

[0332] A schematic illustration shows the pattern of varying heights of the uncoated portions 11 and 12. Specifically, the heights of the uncoated portions 11 and 12 vary irregularly depending on the position of the cut cross-section. For example, when the side portion of the trapezoidal segment 11a is cut, the height of the uncoated portion on the cross-section is lower than the height of the segment 11a. Therefore, the heights of the uncoated portions 11 and 12 illustrated in the cross-section of the electrode assembly 10 correspond to the average height of the uncoated portions included in each winding.

[0333] Reference Figures 26 to 29 The uncoated portions 11 and 12 are bent, for example, from the outer periphery to the core side along the radial direction of the electrode assembly 10. Figure 27 The locations where bending occurs in the uncoated portions 11 and 12 are indicated by dashed boxes. When the uncoated portions 11 and 12 are bent, adjacent segments in the radial direction overlap to form multiple layers, creating bending surfaces 102 on the upper and lower parts of the electrode assembly 10. At this time, the core-side uncoated portion ( Figure 26Because of its low height, the segment 11a (11-1) is not bent. The height h of the segment 11a bent on the innermost side is approximately the same as or shorter than the length r of the winding area formed by the uncoated core portion 11-1 without segment structure and 10% of the winding hole diameter. Therefore, the hole formed in the core of the electrode assembly 10 is not closed. The absence of closed holes eliminates difficulties in the electrolyte injection process, improving electrolyte injection efficiency. Furthermore, the insertion of a welding tool through the hole facilitates welding of the terminal 50 and the first current collector 40 (see reference). Figure 7 ).

[0334] On the other hand, when the outer diameter of the first current collector 40 and / or the second current collector 70 is set to T, the outer diameter of the electrode assembly 10 is set to JR, and the height of the segmented piece of the first uncoated portion 11 and / or the outermost segmented piece of the second uncoated portion 12 is set to F, the following relationship is satisfied. Here, the outer diameter of the first current collector 40 refers to twice the distance from the center of the first current collector 40 to the end of the first uncoated portion joint 42, and the outer diameter of the second current collector 70 refers to twice the distance from the center of the second current collector 70 to the end of the second uncoated portion joint 72.

[0335] JR–2 F≤T <JR

[0336] Preferably, the outer diameter T of the first current collector 40 and / or the second current collector 70 is greater than or equal to the length obtained by subtracting twice the height F of the segmented pieces 11a of the first uncoated portion 11 and / or the segmented pieces of the second uncoated portion 12 from the outer diameter JR of the electrode assembly 10. When this relationship is satisfied, the first uncoated portion joint 42 and / or the second uncoated portion joint 72 covers the end of the outermost segmented piece 11a. That is, the first current collector 40 and / or the second current collector 70 have an outer diameter that covers the end of the bent segmented piece at the last loop of the first electrode. In this case, welding can be performed while all the segmented pieces 11a forming the bent surface 102 with the first uncoated portion joint 42 and / or the second uncoated portion joint 72 are uniformly pressed by the current collector 40, and the tight stacking state of the segmented pieces 11a can be well maintained after welding. Figure 8 As shown, a tight stacking state refers to a state in which there are virtually no gaps between the segments. A tight stacking state is beneficial for reducing the resistance of the cylindrical battery 1 to a level suitable for rapid charging (e.g., below 4mΩ).

[0337] On another note, the outer diameter T of the first current collector 40 and / or the second current collector 70 is smaller than the outer diameter JR of the electrode assembly 10. If the outer diameter T of the first current collector 40 and / or the second current collector 70 is larger than the outer diameter JR of the electrode assembly 10, the dead space inside the casing 20 increases, adversely affecting the energy density of the cylindrical battery 1. Therefore, the outer diameter T of the first current collector 40 and / or the second current collector 70 is preferably smaller than the outer diameter JR of the electrode assembly 10.

[0338] On the other hand, refer to Figure 30 Multiple cylindrical batteries 1 are connected in series and parallel at the top of the cylindrical batteries 1 via a bus 150. The number of cylindrical batteries 1 increases or decreases depending on the capacity of the battery pack.

[0339] In each cylindrical battery 1, the terminal 50 is anode, and the outer surface 20a of the closing portion of the casing 20 is cathode. Of course, the opposite is also possible. In the above-described cylindrical battery 1, both the terminal 50 and the outer surface 20a of the closing portion located on the opposite side of the opening of the casing 20 are arranged facing upwards.

[0340] Preferably, the plurality of cylindrical batteries 1 are arranged in multiple columns and rows. Columns are in a vertical direction relative to the ground, and rows are in a horizontal direction relative to the ground. Furthermore, to maximize space efficiency, the cylindrical batteries 1 are arranged in a closest packing structure. The closest packing structure is formed when the centers of the exposed terminal portions 51 of the terminals 50 exposed to the outside of the housing 20 are connected to each other to form an equilateral triangle. Preferably, the bus 150 is arranged on the upper part of the plurality of cylindrical batteries 1, more preferably between adjacent columns. As a countermeasure, the bus 150 is arranged between adjacent rows.

[0341] Preferably, the bus 150 connects the cylindrical batteries 1 arranged in the same column in parallel with each other, and connects the cylindrical batteries 1 arranged in two adjacent columns in series with each other.

[0342] Preferably, the bus 150 includes a main body 151, a plurality of first bus terminals 152 and a plurality of second bus terminals 153 for serial and parallel connections.

[0343] The main body 151 extends between the terminals 50 of adjacent cylindrical batteries 1, preferably between rows of cylindrical batteries 1. As a countermeasure, the main body 151 extends along the rows of cylindrical batteries 1, and is regularly bent in a zigzag shape.

[0344] Multiple first bus terminals 152 extend from one side of the main body 151 toward the terminals 50 of each cylindrical battery 1 and are electrically connected to the terminals 50. The electrical connection between the first bus terminals 152 and the terminals 50 is achieved by laser welding, ultrasonic welding, or the like. Furthermore, multiple second bus terminals 153 are electrically connected from the other side of the main body 151 to the outer surface 20a of each cylindrical battery 1. The electrical connection between the second bus terminals 153 and the outer surface 20a is achieved by laser welding, ultrasonic welding, or the like.

[0345] Preferably, the main body 151, the plurality of first bus terminals 152, and the plurality of second bus terminals 153 are constituted by a conductive metal plate. The metal plate is, for example, an aluminum plate or a copper plate, but the present invention is not limited thereto. In a variation, the main body 151, the plurality of first bus terminals 152, and the second bus terminals 153 can be manufactured into multiple block units and then joined together by welding or the like.

[0346] In the cylindrical battery 1 of the present invention, the outer surface 20a of the closing portion of the outer casing 20, which has an anode, is located in the same direction, so the electrical connection of the cylindrical battery 1 can be easily realized by means of the bus 150.

[0347] In addition, the outer surface 20a of the terminal 50 of the cylindrical battery 1 and the closing portion of the housing 20 has a wide area, so the bonding area of ​​the bus 150 can be sufficiently ensured, thereby sufficiently reducing the resistance of the battery pack including the cylindrical battery 1.

[0348] Preferably, the cylindrical battery is, for example, a cylindrical battery with a shape factor ratio (defined as the ratio of the diameter of the battery to the height H, which is the ratio of the diameter Φ to the height H) that is approximately greater than 0.4.

[0349] Here, the shape factor refers to the value representing the diameter and height of the cylindrical battery. An embodiment of the cylindrical battery of this invention includes, for example, a 46110 battery, a 4875 battery, a 48110 battery, a 4880 battery, and a 4680 battery. In the shape factor values, the first two digits represent the diameter of the battery, and the remaining digits represent the height of the battery.

[0350] One embodiment of the present invention is a cylindrical battery with a generally cylindrical shape, having a diameter of approximately 46 mm, a height of approximately 110 mm, and a shape factor ratio of approximately 0.418.

[0351] Another embodiment of the cylindrical battery is a generally cylindrical battery with a diameter of approximately 48 mm, a height of approximately 75 mm, and a shape factor ratio of approximately 0.640.

[0352] Another embodiment of the battery is a generally cylindrical battery, which is a cylindrical battery with a diameter of approximately 48 mm, a height of approximately 110 mm, and a shape factor ratio of approximately 0.436.

[0353] Another embodiment of the battery is a generally cylindrical battery, which is a cylindrical battery with a diameter of approximately 48 mm, a height of approximately 80 mm, and a shape factor ratio of approximately 0.600.

[0354] Another embodiment of the battery is a generally cylindrical battery with a diameter of approximately 46 mm, a height of approximately 80 mm, and a shape factor ratio of approximately 0.575.

[0355] Previously, batteries with a form factor ratio of approximately 0.4 or less were used. For example, 1865 and 2170 batteries were previously used. In the case of an 1865 battery, its diameter is approximately 18 mm, its height is approximately 65 mm, and its form factor ratio is approximately 0.277. In the case of a 2170 battery, its diameter is approximately 21 mm, its height is approximately 70 mm, and its form factor ratio is approximately 0.300.

[0356] Reference Figure 31 A battery pack 3 according to one embodiment of the present invention includes a battery assembly consisting of multiple cylindrical batteries 1 electrically connected as described above, and a packaging shell 2 for housing the battery assembly. In the figures of the present invention, for ease of illustration, components such as the bus for electrical connection, cooling unit, and power terminals are omitted. Regarding the electrical connection structure of the multiple cylindrical batteries 1 used to manufacture the battery pack 3, in the above... Figure 30 An illustrative explanation is provided in the text.

[0357] Reference Figure 32 In one embodiment of the present invention, the vehicle 5 is, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle, including a battery pack 3 according to one embodiment of the present invention. The vehicle 5 includes both four-wheeled and two-wheeled vehicles. The vehicle 5 operates by receiving power from the battery pack 3 according to one embodiment of the present invention.

[0358] While the present invention has been described above with reference to specific embodiments and accompanying drawings, the present invention is not limited thereto. Within the technical concept of the present invention and the equivalent scope described below, those skilled in the art can make various modifications and variations.

Claims

1. A battery, characterized by, It includes: An electrode assembly is defined by winding a first electrode, a second electrode, and a separation membrane between them around a winding shaft to define the core and outer peripheral surfaces. The first electrode includes a first uncoated portion at its long side end along the winding direction, which is not coated with an active material layer and is exposed to the outside of the separation membrane. At least a portion of the first uncoated portion is itself used as an electrode tab. The second electrode also includes a second uncoated portion at its long side end along the winding direction. The second uncoated portion is not coated with an active material layer and extends in the opposite direction to the first uncoated portion, exposing to the outside of the separation membrane. The housing includes an opening on one side through which the electrode assembly is housed, and the housing is electrically connected to the second uncoated portion. A first current collector includes: an edge portion disposed on the upper part of the electrode assembly; a first uncoated portion joining portion extending inward from the edge portion and joining with the first uncoated portion; a terminal joining portion located at the center of the inner space of the edge portion, wherein the terminal joining portion is separate from the first uncoated portion joining portion, such that the terminal joining portion is not directly connected to the first uncoated portion joining portion but is connected to the first uncoated portion joining portion through the edge portion; and a connecting portion extending inward from the edge portion and connecting with the terminal joining portion; and The terminal passes through the closed portion located on the opposite side of the open portion of the housing and is coupled to the terminal coupling portion, and the terminal is insulated from the housing.

2. The battery according to claim 1, characterized in that, The aforementioned edge portion has a frame shape with its inner space empty.

3. The battery according to claim 1, characterized in that, The first uncoated portion and the terminal portion are electrically connected via the edge portion.

4. The battery according to claim 1, characterized in that, At least a portion of the aforementioned connecting portion has a smaller cross-sectional area compared to the aforementioned first uncoated portion joint portion.

5. The battery according to claim 4, characterized in that, At least a portion of the aforementioned connecting portion is smaller in either width or thickness than the aforementioned first uncoated portion joint portion.

6. The battery according to claim 1, characterized in that, The aforementioned connecting portion has a tapered portion, the width of which narrows continuously or in stages from the inner side of the aforementioned edge portion along the direction toward the aforementioned terminal joint portion.

7. The battery according to claim 1, characterized in that, The aforementioned first uncoated portion has multiple joints.

8. The battery according to claim 7, characterized in that, The plurality of the aforementioned first uncoated portions are regularly arranged along the extending direction of the aforementioned edge portions.

9. The battery according to claim 7, characterized in that, The extension lengths of the various first uncoated portions are substantially the same.

10. The battery according to claim 7, characterized in that, The cross-sectional areas of the various first uncoated portions mentioned above are substantially the same.

11. The battery according to claim 7, characterized in that, The width and thickness of each of the aforementioned first uncoated portions are substantially the same.

12. The battery according to claim 7, characterized in that, The aforementioned terminal joint is arranged to be surrounded by a plurality of the aforementioned first uncoated joints.

13. The battery according to claim 7, characterized in that, The aforementioned connecting portion is disposed between a pair of adjacent first uncoated portions.

14. The battery according to claim 13, characterized in that, The distance from the connecting portion along the extending direction of the edge portion to either of the two adjacent first uncoated portion joints is substantially the same as the distance to the other first uncoated portion joint.

15. The battery according to claim 7, characterized in that, The aforementioned connecting parts are multiple.

16. The battery according to claim 15, characterized in that, The aforementioned connecting portions are respectively disposed between a pair of adjacent first uncoated portions.

17. The battery according to claim 15, characterized in that, The aforementioned connecting portions are regularly arranged along the extending direction of the aforementioned edge portions.

18. The battery according to claim 16, characterized in that, The distance from the aforementioned multiple connecting portions to any one of the aforementioned adjacent first uncoated portion joints along the extension direction of the aforementioned edge portions is substantially the same as the distance to the other first uncoated portion joint.

19. The battery according to claim 1, characterized in that, The aforementioned connection portion includes a current cutting-off portion formed in a manner that reduces the cross-sectional area of ​​the aforementioned connection portion.

20. The battery according to claim 19, characterized in that, The aforementioned current cutting-off portion is a region having a shape in which at least one of its width and thickness is reduced compared to the remaining region of the aforementioned connecting portion.

21. The battery according to claim 19, characterized in that, The aforementioned current cutting-off portion includes at least one of a recess, a groove, and a through hole formed on at least one side of the aforementioned connection portion.

22. The battery according to claim 1, characterized in that, The terminal joint is positioned at a location corresponding to the hole formed in the winding center portion of the electrode assembly.

23. The battery according to claim 22, characterized in that, The terminal connection portion has a structure that covers the hole formed in the winding center portion of the electrode assembly, so that the hole formed in the winding center portion of the electrode assembly is not exposed to the outside of the terminal connection portion.

24. The battery according to claim 22, characterized in that, The diameter of the terminal joint is greater than or equal to the diameter of the hole formed in the winding center portion of the electrode assembly.

25. The battery according to claim 1, characterized in that, The first uncoated portion extends toward the closed portion located on the opposite side of the open portion of the housing.

26. The battery according to claim 25, characterized in that, The first uncoated portion is joined to the joint surface formed by bending the end of the first uncoated portion along a direction parallel to the first current collector.

27. The battery of claim 1, wherein, It also includes: A cover plate that seals the opening of the aforementioned outer casing.

28. The battery according to claim 27, characterized in that, The cover plate is not electrically connected to the electrode assembly and therefore does not have polarity.

29. The battery according to claim 27, characterized in that, The aforementioned outer casing includes: A rolled edge portion, formed adjacent to the aforementioned open portion, and having a shape that is pressed inward toward the inside of the aforementioned outer casing; and The crimped portion is formed at the lower part of the aforementioned rolled edge portion and extends and bends around the edge of the aforementioned cover plate.

30. The battery of claim 29, wherein, It also includes: A sealing gasket is disposed within the aforementioned pressing portion, between the aforementioned outer shell and the aforementioned cover plate.

31. The battery according to claim 1, characterized in that, The aforementioned terminal passes through the center of the aforementioned closing portion.

32. The battery according to claim 1, characterized in that, An insulating pad is sandwiched between the aforementioned housing and the aforementioned terminals.

33. The battery of claim 1, wherein, It also includes: An insulator located between a closed portion on the opposite side of the open portion of the aforementioned housing and the aforementioned first current collector.

34. The battery according to claim 33, characterized in that, The insulator has a thickness corresponding to the distance between the inner surface of the closing portion of the housing and the first current collector.

35. The battery according to claim 34, characterized in that, The aforementioned terminals are connected to the terminal connection portion of the first current collector through holes formed in the aforementioned insulator.

36. The battery according to claim 35, characterized in that, The lower end of the terminal that is coupled to the above-mentioned terminal joint is located at the same height as or closer to the upper part of the lower surface of the above-mentioned insulator.

37. The battery according to claim 33, characterized in that, The aforementioned insulator is located between the aforementioned first uncoated portion and the sidewall of the aforementioned housing.

38. The battery according to claim 33, characterized in that, The upper surface of the insulator is in contact with the inner surface of the closed portion located on the opposite side of the open portion of the housing, and the lower surface of the insulator is in contact with the upper surface of the first current collector.

39. The battery of claim 1, wherein, It also includes: The second current collector is connected to the second uncoated portion and the outer casing respectively, and electrically connects the second uncoated portion and the outer casing.

40. The battery according to claim 39, characterized in that, The second current collector described above includes a second current collector hole, which is formed in a region corresponding to the hole formed in the winding center of the electrode assembly described above.

41. The battery according to claim 40, characterized in that, The second current collector hole has the same or larger diameter as the hole formed at the winding center of the electrode assembly, so as not to block the hole formed at the winding center of the electrode assembly.

42. The battery according to claim 39, characterized in that, The aforementioned second current collector includes: The second uncoated portion is joined to the aforementioned second uncoated portion; and The outer shell joint is joined to the aforementioned outer shell.

43. The battery according to claim 42, characterized in that, The aforementioned second uncoated portion and the aforementioned joint portion of the second uncoated portion are joined together by welding.

44. The battery according to claim 42, characterized in that, The aforementioned outer shell and the aforementioned outer shell joint are joined together by welding.

45. The battery according to claim 42, characterized in that, The aforementioned outer casing has a rolled edge portion, which is formed adjacent to the aforementioned open portion and has a shape that is pressed inward.

46. ​​The battery according to claim 45, characterized in that, The aforementioned outer casing joint is electrically bonded to the lower surface of the aforementioned rolled edge portion.

47. The battery according to claim 42, characterized in that, The distance from the center of the first current collector to the outermost part of the edge portion is longer than the distance from the center of the second current collector to the outermost part of the second uncoated portion joint.

48. The battery according to claim 47, characterized in that, The distance from the center of the second current collector to the outermost part of the second uncoated portion joint is less than or equal to half the inner diameter of the area where the rolled edge of the outer shell is formed.

49. The battery according to claim 1, characterized in that, At least a portion of the first uncoated portion includes a plurality of segmented pieces divided along the winding direction of the electrode assembly. The aforementioned segmented pieces are bent along the radial direction of the aforementioned electrode assembly.

50. The battery according to claim 49, characterized in that, The aforementioned curved segments overlap to form multiple layers.

51. The battery according to claim 50, characterized in that, The electrode assembly described above has a welding target area, which is an area in which the number of overlapping segments of the first uncoated portion is maintained at a certain level along the radial direction of the electrode assembly.

52. The battery according to claim 42, characterized in that, At least a portion of the second uncoated portion includes a plurality of segmented pieces divided along the winding direction of the electrode assembly. The aforementioned segmented pieces are bent along the radial direction of the aforementioned electrode assembly.

53. The battery according to claim 52, characterized in that, The aforementioned curved segmented pieces overlap to form multiple layers.

54. The battery according to claim 53, characterized in that, The electrode assembly described above has a welding target area, which is an area in which the number of overlapping segments of the second uncoated portion is maintained at a certain level along the radial direction of the electrode assembly.

55. The battery according to claim 1, characterized in that, The first current collector further includes a bridging portion that connects at least one of the following: adjacent first uncoated portion joints, adjacent first uncoated portion joints and connecting portions, and adjacent connecting portions.

56. The battery according to claim 55, characterized in that, The aforementioned bridging portion is positioned further inward than the aforementioned edge portion.

57. The battery according to claim 56, characterized in that, The first current collector has an impregnation hole formed between the edge portion and the bridging portion.

58. The battery according to claim 57, characterized in that, The impregnation hole has a slit shape that extends along the extension direction of the edge portion.

59. The battery according to claim 1, characterized in that, The ratio of the area of ​​the first current collector that does not contact the upper surface of the electrode assembly to the area of ​​a circle with the outer diameter of the electrode assembly is 20% or more and less than 100%.

60. The battery according to claim 19, characterized in that, The number of the aforementioned connecting parts is one or two.

61. The battery according to claim 19, characterized in that, The ratio of the cross-sectional area of ​​the connecting portion in the region where the current cutting portion is formed to the cross-sectional area of ​​the connecting portion in the region adjacent to the region where the current cutting portion is formed is 0.6 to 0.

9.

62. The battery according to claim 19, characterized in that, The ratio of the cross-sectional area of ​​the aforementioned connecting portion to the cross-sectional area of ​​the aforementioned first uncoated portion joint portion is 0.2 to 1.

0.

63. The battery according to claim 1, characterized in that, The ratio of the outer diameter of the first current collector to the inner diameter of the outer casing is in the range of 33% to 98.5%.

64. The battery according to claim 51, characterized in that, The aforementioned welding target area is the area where the number of overlapping layers of the aforementioned multiple segmented pieces remains the largest.

65. The battery according to claim 51, characterized in that, The first current collector is welded to the first uncoated portion in such a way that it overlaps with the welding target area by at least 50%.

66. The battery according to claim 54, characterized in that, The aforementioned welding target area is the area where the number of overlapping layers of the aforementioned multiple segmented pieces remains the largest.

67. The battery according to claim 66, characterized in that, The second current collector is welded to the second uncoated portion in such a way that it overlaps with the welding target area by at least 50%.

68. The battery according to claim 1, characterized in that, The resistance measured between the anode and cathode is less than 4mΩ.

69. The battery according to claim 19, characterized in that, The aforementioned current-cutting portion is formed at a location that is separated from the core of the aforementioned electrode assembly by 40% to 90% along the radial direction based on the radius of the electrode assembly.

70. The battery according to claim 19, characterized in that, At least a portion of the first uncoated portion includes a plurality of segmented sheets divided along the winding direction of the electrode assembly, the plurality of segmented sheets being bent and overlapped into multiple layers along the radial direction of the electrode assembly. The aforementioned current cutting-off section is located in a region corresponding to the welding target region, which is a region in which the number of overlaps of the aforementioned segmented pieces of the aforementioned first uncoated portion remains constant along the radial direction of the aforementioned electrode assembly.

71. The battery according to claim 19, characterized in that, A belt is attached to the aforementioned current cutting section.

72. The battery according to claim 71, characterized in that, The strip mentioned above is made of polyimide.

73. The battery according to claim 71, characterized in that, The aforementioned strip is configured to surround the aforementioned connection portion in the region where the aforementioned current cutting-off portion is formed.

74. The battery according to claim 49, characterized in that, When the outer diameter of the first current collector is set to T, the outer diameter of the electrode assembly is set to JR, and the height of the segment located at the outermost edge of the electrode assembly in the radial direction is set to F, the following relationship is satisfied: JR - 2 F < T < JR.

75. The battery according to claim 1, characterized in that, The welding pattern drawn by the weld bead formed on one side of the terminal joint of the first current collector has a shape that surrounds the center of the bottom surface of the terminal.

76. The battery according to claim 75, characterized in that, The above welding patterns can be formed continuously or discontinuously.

77. The battery according to claim 1, characterized in that, The tensile force of the weld between the terminal joint of the first current collector and the bottom surface of the terminal is 2 kgf or more.

78. The battery according to claim 77, characterized in that, The equivalent diameter of the welding pattern drawn by the weld bead formed on one side of the terminal joint of the first current collector is 2 mm or more.

79. The battery according to claim 78, characterized in that, The diameter of the flat portion formed on the bottom surface of the aforementioned terminal is 3 mm to 14 mm.

80. The battery according to claim 77, characterized in that, The ratio of the area of ​​the weld pattern drawn by the weld bead formed on the surface of the terminal joint of the first current collector to the area of ​​the flat portion formed on the bottom surface of the terminal is 2.04% to 44.4%.

81. The battery according to claim 40, characterized in that, The second current collector hole has a smaller diameter than the winding hole formed at the winding center of the electrode assembly.

82. The battery according to claim 81, characterized in that, When the diameter of the aforementioned winding hole is set to R3, The diameter of the above-mentioned second current collector hole is 0.5 R3 is greater than and less than R3.

83. The battery according to claim 81, characterized in that, When the diameter of the aforementioned winding hole is set to R3, The diameter of the above-mentioned second current collector hole is 0.7 R3 is greater than and less than R3.

84. The battery according to claim 1, characterized in that, The ratio of the shape factor obtained by dividing the diameter of the battery by its height is greater than 0.

4.

85. The battery according to claim 42, characterized in that, The length of the welded portion that joins the first uncoated portion and the first uncoated portion along the radial direction of the electrode assembly is longer than the length of the welded portion that joins the second uncoated portion and the second uncoated portion along the radial direction of the electrode assembly.

86. The battery according to claim 42, characterized in that, Based on the core of the electrode assembly, the distance to the starting point of the welded portion that joins the first uncoated portion and the first uncoated portion is substantially the same as the distance to the starting point of the welded portion that joins the second uncoated portion and the second uncoated portion.

87. The battery according to claim 20, characterized in that, Multiple current-cutting sections are provided along the length of the connection section.

88. The battery according to claim 1, characterized in that, No welded portion is formed at the connection between the aforementioned edge portion and the aforementioned terminal portion.

89. A battery pack, comprising: include: The battery according to any one of claims 1 to 88; and The outer packaging shell houses multiple of the aforementioned batteries.

90. The battery pack according to claim 89, characterized in that, Multiple of the above-mentioned batteries are arranged in a predetermined number of columns. The terminals of each of the aforementioned batteries and the outer surface of the closed portion of the aforementioned housing, located on the opposite side of the open portion of the aforementioned housing, are arranged facing upwards.

91. The battery pack according to claim 90, characterized in that, The aforementioned battery pack includes multiple buses that connect multiple batteries in series and in parallel. The aforementioned multiple buses are configured on the upper part of the aforementioned batteries. Each of the above buses includes: The main body extends between the terminals of adjacent batteries; A plurality of first bus terminals, which extend in one direction of the aforementioned main body and are electrically coupled to terminals of a battery located in the aforementioned one direction; and Multiple second bus terminals extend in the direction of the other side of the main body and are electrically coupled to the outer surface of the closing part of the battery casing located in the direction of the other side.

92. An automobile characterized by comprising: It includes the battery pack as described in claim 89.

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