Secondary battery and method of manufacturing secondary battery

Abstract

The present disclosure relates to a secondary battery and a method of manufacturing a secondary battery. The secondary battery according to the present disclosure includes an electrode assembly and a current collector. The current collector includes a current collecting unit and a pole unit. The current collecting unit includes a first current collecting portion, a second current collecting portion, and a connection portion. The first current collecting portion can be welded to a plurality of first electrode tabs of the electrode assembly, the second current collecting portion can be welded to a plurality of second electrode tabs of the electrode assembly, and the first electrode tabs and the second electrode tabs have the same polarity. The connection portion is connected to the first current collecting portion and is formed with an opening. The pole unit can be coupled to the current collecting unit and can include a current collecting protrusion. According to the present disclosure, the manufacturing and assembly processes of the secondary battery can be simplified.

Description

Cross-references to related applications

[0001] This application claims priority to Korean patent applications No. 10-2025-0052610, No. 10-2025-0182411, No. 10-2025-0210849, No. 10-2026-0028381, and No. 10-2026-0052537, filed on April 22, 2025, November 26, 2025, December 26, 2025, February 12, 2026, and March 24, 2026, respectively, the disclosures of which are incorporated herein by reference in their entirety. Background Technology Technical Field

[0002] This disclosure relates to secondary batteries, and more specifically, to secondary batteries capable of reducing the risk of damage to separators.

[0003] Related technologies

[0004] Recently, with the rapid increase in demand for portable electronic devices and the more active development of electric vehicles, energy storage batteries, robots, satellites, etc., high-performance rechargeable and rechargeable batteries have been extensively studied.

[0005] Secondary batteries can be classified according to the shape of their casing into can-type secondary batteries, in which the electrode components are embedded in a metal can, and bag-type secondary batteries, in which the electrode components are embedded in a pouch formed of aluminum laminates. Can-type secondary batteries can also be classified according to the shape of the metal can, into cylindrical secondary batteries and prismatic secondary batteries.

[0006] In a secondary battery, the electrode contacts and current collectors of the electrode assembly are connected to each other by welding. When the electrode contacts are connected to the current collector, the electrode contacts are bent in the bending direction to increase the contact area between the electrode contacts and the current collector. After this, the current collector is placed on the upper part of the electrode contacts and welded to the upper part of the electrode contacts.

[0007] However, in this case, there is a risk that the separator may be damaged during the process of welding the current collector to the electrode contacts located below the current collector. In addition, as the capacity of the secondary battery increases, the number of electrode contacts that need to be welded at one time increases, and therefore, there is a risk that the electrode contacts spaced apart from the current collector may not be welded correctly.

[0008] Therefore, there is a need to develop a secondary battery that can reduce the risk of damage to the separator and stably weld a large number of electrode tabs to the current collector. Additionally, there is a need to develop a secondary battery that simplifies the assembly process. Summary of the Invention

[0009] Therefore, the purpose of this disclosure is to provide a current collector that is easy to manufacture and assemble.

[0010] Another object of this disclosure is to provide a method for manufacturing a secondary battery that simplifies the manufacturing and assembly process.

[0011] Another object of this disclosure is to provide a secondary battery including a current collector, wherein the electrode units of the current collector are stably connected to the current collector unit.

[0012] Another object of this disclosure is to provide a secondary battery that simplifies the assembly process of a secondary battery.

[0013] A secondary battery according to one aspect of this disclosure may include an electrode assembly and a current collector. The electrode assembly may include an electrode portion and a plurality of electrode tabs formed on one end of the electrode portion. The current collector may be disposed on the end of the electrode portion and welded to the electrode tabs. The current collector may include a current collector unit and an electrode unit. The current collector unit may include a first current collector portion, a second current collector portion, and a connecting portion. The first current collector portion may be welded to a plurality of first electrode tabs among the plurality of electrode tabs. The second current collector portion may be welded to a plurality of second electrode tabs among the plurality of electrode tabs. The second electrode tabs and the first electrode tabs have the same polarity. The connecting portion may be connected to the first current collector portion. An opening may be formed in the connecting portion. The electrode unit may be connected to the current collector unit. The electrode unit may include a current collector protrusion and a support portion connected to the lower end of the current collector protrusion. The cross-sectional area of ​​the support portion is larger than the cross-sectional area of ​​the current collector protrusion. The current collector includes a stop portion that forms a stepped structure within the current collector.

[0014] According to one aspect of this disclosure, a recessed region is formed on the lower surface of the current collection unit, and the opening and the recessed region of the connection portion can be joined together in the thickness direction of the connection portion to penetrate the connection portion.

[0015] According to one aspect of this disclosure, a stop is provided on the connecting portion and has an opening.

[0016] According to one aspect of this disclosure, the support portion can be received in a recessed area.

[0017] According to one aspect of this disclosure, the lower surface of the current collection unit may be flush with the lower surface of the support portion.

[0018] According to one aspect of this disclosure, the upper surface of the stop portion may be flush with the upper surface of the support portion.

[0019] According to one aspect of this disclosure, the stop portion may have a square plate shape, a rectangular plate shape, or a disc shape.

[0020] According to one aspect of this disclosure, the stop portion can be integrally formed with the connecting portion.

[0021] According to one aspect of this disclosure, the height of the stop portion can be in the range of 30% to 50% of the height of the end of the current collection unit.

[0022] According to one aspect of this disclosure, the height of the stop portion can be in the range of 1% to 5% of the thickness of the electrode assembly.

[0023] According to one aspect of this disclosure, the depth of the recessed region can be in the range of 30% to 50% of the height of the end of the current collection unit.

[0024] According to one aspect of this disclosure, a recessed region may be formed below the stop portion. The cross-sectional area of ​​the recessed region may be smaller than the cross-sectional area of ​​the stop portion.

[0025] According to one aspect of this disclosure, the depth of the recessed region can be equal to the height of the end of the current collection unit.

[0026] According to one aspect of this disclosure, the outer peripheral surface of the flow collecting protrusion and the inner peripheral surface of the opening of the stop portion can be spaced apart from each other by a predetermined distance.

[0027] According to one aspect of this disclosure, the outer peripheral surface of the support portion and the inner peripheral surface of the recessed region can be spaced apart from each other by a predetermined distance.

[0028] According to one aspect of this disclosure, the pole unit may further include a flange formed between the current collector protrusion and the support portion, the pole unit being connected to the current collector such that the flange is mounted on the connecting portion to form a stop portion.

[0029] According to one aspect of this disclosure, the support portion can be inserted into the opening.

[0030] According to one aspect of this disclosure, the lower surface of the support portion can be positioned above the lower surface of the current collection unit.

[0031] According to one aspect of this disclosure, the flange may have a square plate shape, a rectangular plate shape, or a disc shape.

[0032] According to one aspect of this disclosure, the flow collection protrusion, the support portion, and the flange can be integrally formed.

[0033] According to one aspect of this disclosure, the height of the flange can be in the range of 30% to 50% of the height of the end of the current collector unit.

[0034] According to one aspect of this disclosure, the height of the flange can be in the range of 1% to 5% of the thickness of the electrode assembly.

[0035] According to one aspect of this disclosure, a welding area may be formed on the periphery of the lower surface of the support portion to weld the pole unit and the current collector unit together.

[0036] According to one aspect of this disclosure, a welding area may be formed on the entire lower surface of the support portion, the welding area including a first welding area formed on the periphery of the lower surface of the support portion and a second welding area located inside the first welding area, wherein the laser output of the first welding area is higher than the laser output of the second welding area.

[0037] According to one aspect of this disclosure, the material of the current collector unit can be the same as the material of the pole unit.

[0038] According to one aspect of this disclosure, the material of the current collector unit may be different from the material of the pole unit.

[0039] According to one aspect of this disclosure, the pole unit further includes a protruding end, the protruding end and the flange being located on opposite sides of the support portion, and the cross-sectional area of ​​the protruding end being smaller than the cross-sectional area of ​​the support portion.

[0040] According to one aspect of this disclosure, the current collector is used as a negative current collector, and a nickel plating layer may be formed on the upper end of the current collector protrusion.

[0041] According to one aspect of this disclosure, the support portion is partially located in the opening, and a portion of the support portion protrudes from the connecting portion to form a stop.

[0042] According to one aspect of this disclosure, the first current collection section, the second current collection section, and the connecting section are arranged in any of the following ways: the first current collection section, the second current collection section, and the connecting section are arranged continuously along the longitudinal direction of the current collection unit; the first current collection section, the connecting section, and the second current collection section are arranged continuously along the longitudinal direction of the current collection unit; the first current collection section and the second current collection section are respectively connected to the two ends of the same side of the connecting section.

[0043] According to one aspect of this disclosure, the cross-sectional area of ​​the recessed region on the lower surface of the current collector is smaller than the cross-sectional area of ​​the opening, such that a step is formed between the opening and the recessed region.

[0044] According to one aspect of this disclosure, the support portion rests partially on the step portion, and the protruding end is received in the recessed area.

[0045] According to one aspect of this disclosure, the lower surface of the protruding end is flush with or higher than the lower surface of the current collector unit.

[0046] According to one aspect of this disclosure, the recessed region on the lower surface of the current collector has an inclined peripheral wall, such that the cross-sectional area of ​​the recessed region gradually decreases in the direction toward the opening.

[0047] According to one aspect of this disclosure, the current collection protrusion includes a first current collection protrusion, a second current collection protrusion, and a connecting portion, the connecting portion connecting between the first current collection protrusion and the second current collection protrusion, the first current collection protrusion being connected to a flange, and the cross-sectional area of ​​the first current collection protrusion being larger than the cross-sectional area of ​​the second current collection protrusion.

[0048] According to one aspect of this disclosure, the pole cell is connected to the current collector such that the lower surface of the pole cell is lower than the upper surface of the current collector.

[0049] According to one aspect of this disclosure, the cross-sectional area of ​​the support portion is in the range of 150% to 300% of the cross-sectional area of ​​the flow collection protrusion.

[0050] According to one aspect of this disclosure, a plurality of first electrode contacts are bent toward the upper surface of the first current collecting portion of the current collecting unit of the current collector, and a plurality of second electrode contacts are bent toward the upper surface of the second current collecting portion of the current collecting unit in a direction opposite to the bending direction of the plurality of first electrode contacts. The spacing between the first electrode contacts and the second electrode contacts is 5% to 15% of the length of the current collector.

[0051] According to one aspect of this disclosure, a plurality of first electrode contacts are soldered to a first current collector, and a plurality of second electrode contacts are soldered to a second current collector.

[0052] According to one aspect of this disclosure, the secondary battery further includes: a housing, an electrode assembly housed within the housing, an opening formed at one end of the housing; and a cover assembly that seals the opening of the housing and includes a cover plate and electrode terminals. A current collector protrusion is inserted into a through-hole of the electrode terminals.

[0053] According to one aspect of this disclosure, the manifold protrusion is welded to the through hole at its end.

[0054] A secondary battery according to one aspect of this disclosure may include an electrode assembly and a current collector. The electrode assembly may include an electrode portion and a plurality of electrode tabs formed on one end of the electrode portion. The current collector may be disposed on the end of the electrode portion and soldered to the electrode tabs. The current collector may include a current collector unit and an electrode unit. The current collector unit may include a first current collector portion, a second current collector portion, and a connecting portion. The first current collector portion may be soldered to a plurality of first electrode tabs among the plurality of electrode tabs. The second current collector portion may be soldered to a plurality of second electrode tabs among the plurality of electrode tabs. The second electrode tabs and the first electrode tabs have the same polarity. The connecting portion may be connected to the first current collector portion and may include a seating area formed in the upper surface of the connecting portion. The electrode unit may be coupled to the current collector unit and may include a current collector protrusion. The current collector includes a stop portion that forms a stepped structure within the current collector.

[0055] According to one aspect of this disclosure, the seating area may be recessed downward from the upper surface of the connecting portion, and the depth of the seating area may be in the range of 30% to 50% of the height of the end of the current collection unit.

[0056] According to one aspect of this disclosure, the pole unit may further include a support portion connected to the lower end of the current collecting protrusion and seated in the seating region. A portion of the support portion protrudes from the upper surface of the connecting portion to form a stop.

[0057] According to one aspect of this disclosure, the height by which the support portion protrudes from the upper surface of the current collector can be in the range of 1% to 5% of the thickness of the electrode assembly.

[0058] According to one aspect of this disclosure, the support portion may have a square plate shape, a rectangular plate shape, or a disc shape.

[0059] According to one aspect of this disclosure, the pole cell is connected to the current collector such that the lower surface of the pole cell is lower than the upper surface of the current collector.

[0060] According to one aspect of this disclosure, the cross-sectional area of ​​the support portion is in the range of 150% to 300% of the cross-sectional area of ​​the flow collection protrusion.

[0061] According to one aspect of this disclosure, the connecting portion can be connected to a side of the first collector portion and protrude relative to the upper surface of the first collector portion to form a stop portion.

[0062] According to one aspect of this disclosure, the upper surface of the seating area may be flush with the upper surface of the connecting portion and may be connected to the lower surface of the collecting protrusion.

[0063] According to one aspect of this disclosure, the height of the connection portion protruding relative to the first current collector portion can be in the range of 1% to 5% of the thickness of the electrode assembly.

[0064] According to one aspect of this disclosure, the surface of the connection between the connecting portion and the first current collection portion may be inclined.

[0065] According to one aspect of this disclosure, the thickness of the connecting portion may be equal to the thickness of each of the first and second current collector portions.

[0066] According to one aspect of this disclosure, a welding area may be formed in the lower surface of the connecting portion corresponding to the seating area.

[0067] According to one aspect of this disclosure, the welding area includes a first welding area corresponding to the periphery of the lower surface of the pole unit.

[0068] According to one aspect of this disclosure, the welding area also includes a second welding area located inside the first welding area, wherein the laser output of the first welding area is higher than the laser output of the second welding area.

[0069] According to one aspect of this disclosure, the material of the current collector unit can be the same as the material of the pole unit.

[0070] According to one aspect of this disclosure, the material of the current collector unit may be different from the material of the pole unit.

[0071] According to one aspect of this disclosure, the current collector is used as a negative current collector, and a nickel plating layer may be formed on the upper end of the current collector protrusion.

[0072] According to one aspect of this disclosure, in the current collection unit, the connecting portion can be connected to one side of the first current collection portion, and the second current collection portion can be connected to the opposite side of the first current collection portion.

[0073] According to one aspect of this disclosure, in the current collection unit, the connection portion may be disposed between the first current collection portion and the second current collection portion.

[0074] According to one aspect of this disclosure, in the current collection unit, a first current collection portion may be connected to the upper end of one side of the connecting portion, and a second current collection portion may be connected to the lower end of said one side of the connecting portion.

[0075] According to one aspect of this disclosure, a plurality of first electrode contacts are bent toward the upper surface of the first current collecting portion of the current collecting unit of the current collector, and a plurality of second electrode contacts are bent toward the upper surface of the second current collecting portion of the current collecting unit in a direction opposite to the bending direction of the plurality of first electrode contacts. The spacing between the first electrode contacts and the second electrode contacts is 5% to 15% of the length of the current collector.

[0076] According to one aspect of this disclosure, a plurality of first electrode contacts are soldered to a first current collector, and a plurality of second electrode contacts are soldered to a second current collector.

[0077] According to one aspect of this disclosure, the secondary battery further includes: a housing, an electrode assembly housed within the housing, an opening formed at one end of the housing; and a cover assembly that seals the opening of the housing and includes a cover plate and electrode terminals. A current collector protrusion is inserted into a through-hole of the electrode terminals.

[0078] According to one aspect of this disclosure, the manifold protrusion is welded to the through hole at its end.

[0079] According to one aspect of this disclosure, a method for manufacturing a secondary battery is provided. The method includes: preparing an electrode assembly, the electrode assembly including an electrode portion and a plurality of electrode tabs formed on one end of the electrode portion; welding a plurality of first electrode tabs among the plurality of electrode tabs to each other, and welding a plurality of second electrode tabs among the plurality of electrode tabs to each other, the first electrode tabs and the second electrode tabs having the same polarity; providing a current collector and disposing the current collector between the plurality of first electrode tabs and the plurality of second electrode tabs; bending the plurality of first electrode tabs toward an upper surface of a first current collecting portion of the current collector, and bending the plurality of second electrode tabs toward an upper surface of a second current collecting portion of the current collector; and welding the plurality of first electrode tabs to the upper surface of the first current collecting portion, and welding the plurality of second electrode tabs to the upper surface of the second current collecting portion.

[0080] According to one aspect of this disclosure, a current collector is provided including a connection portion that connects the current collector's pole units to the current collector units, and welding is performed in a welding area on the lower surface of the current collector to weld the pole units and the current collector units together.

[0081] According to one aspect of this disclosure, connecting the pole unit of the current collector to the connection portion includes: connecting the pole unit from below the current collector to the connection portion such that the current collection protrusion of the pole unit passes through the opening of the connection portion and protrudes from the upper surface of the connection portion, and the lower surface of the pole unit is positioned flush with or higher than the lower surface of the current collector.

[0082] According to one aspect of this disclosure, connecting the current collector's pole unit to the connection portion includes: connecting the pole unit downward from above the connection portion to the connection portion such that the current collection protrusion of the pole unit protrudes from the upper surface of the connection portion.

[0083] According to one aspect of this disclosure, the support portion of the pole unit is at least partially accommodated in the opening or seating area of ​​the connection portion.

[0084] According to one aspect of this disclosure, the welding area includes a first welding area corresponding to the periphery of the lower surface of the pole unit.

[0085] According to one aspect of this disclosure, the welding area further includes a second welding area located inside the first welding area, wherein the laser output used for welding in the first welding area is higher than the laser output used for welding in the second welding area. Attached Figure Description

[0086] Figure 1 This is a view illustrating a secondary battery according to a first embodiment of the present disclosure.

[0087] Figure 2This is a view illustrating the separation of the cover assembly and the electrode assembly in a secondary battery according to a first embodiment of the present disclosure.

[0088] Figure 3 This is a view illustrating an electrode assembly in a secondary battery according to a first embodiment of the present disclosure, wherein a plurality of first electrode contacts and a plurality of second electrode contacts are formed on the electrode portion.

[0089] Figure 4A and Figure 4B This is a view illustrating the first electrode element and the second electrode element in a secondary battery according to a first embodiment of the present disclosure.

[0090] Figure 5A and Figure 5B This is a view illustrating the third and fourth electrode elements in a secondary battery according to a first embodiment of the present disclosure.

[0091] Figure 6 This is a view illustrating a current collector in a secondary battery according to a first embodiment of the present disclosure.

[0092] Figure 7 This is a view illustrating a current collector in a secondary battery according to a first embodiment of the present disclosure.

[0093] Figure 8 It is along Figure 7 A cross-sectional view taken by line A-A'.

[0094] Figure 9 This is a view illustrating a current collector unit in a secondary battery according to a first embodiment of the present disclosure.

[0095] Figure 10A and Figure 10B This is a view illustrating the electrode cells in a secondary battery according to a first embodiment of the present disclosure.

[0096] Figure 11 This is a view illustrating the process of assembling the current collector and the polarity unit in a first embodiment of the present disclosure.

[0097] Figure 12 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a first embodiment of the present disclosure.

[0098] Figure 13 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a modified example of the first embodiment of the present disclosure.

[0099] Figure 14 This is a view illustrating the connection portion and electrode unit in the current collector of a secondary battery according to a second embodiment of the present disclosure.

[0100] Figure 15 It is along Figure 14 A cross-sectional view taken from line B-B'.

[0101] Figure 16 This is a view illustrating the current collector unit in a secondary battery according to a second embodiment of the present disclosure.

[0102] Figure 17A and Figure 17B This is a view illustrating the electrode cells in a secondary battery according to a second embodiment of the present disclosure.

[0103] Figure 18 This is a view illustrating the process of assembling the current collector and the pole unit in a second embodiment of the present disclosure.

[0104] Figure 19 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a second embodiment of the present disclosure.

[0105] Figure 20 This is a view illustrating a current collector in a secondary battery according to a third embodiment of the present disclosure.

[0106] Figure 21 It is along Figure 20 A cross-sectional view taken from line C-C'.

[0107] Figure 22 This is a view illustrating the current collector unit in a secondary battery according to a third embodiment of the present disclosure.

[0108] Figure 23A and Figure 23B This is a view illustrating the electrode cells in a secondary battery according to a third embodiment of the present disclosure.

[0109] Figure 24 This is a view illustrating the process of assembling the current collector and the pole unit in a third embodiment of the present disclosure.

[0110] Figure 25 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a third embodiment of the present disclosure.

[0111] Figure 26 This is a view illustrating the current collector in a secondary battery according to a fourth embodiment of the present disclosure.

[0112] Figure 27 This is a view illustrating the current collector unit in a secondary battery according to the fourth embodiment of the present disclosure.

[0113] Figure 28A and Figure 28B This is a view illustrating the electrode cells in a secondary battery according to a fourth embodiment of the present disclosure.

[0114] Figure 29 This is a view illustrating the process of assembling the current collector and the polarity unit in the fourth embodiment of this disclosure.

[0115] Figure 30 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a fourth embodiment of the present disclosure.

[0116] Figure 31 This is a view illustrating a current collector in a secondary battery according to a fifth embodiment of the present disclosure.

[0117] Figure 32 This is a view illustrating the current collector unit in a secondary battery according to a fifth embodiment of the present disclosure.

[0118] Figure 33A and Figure 33B This is a view illustrating the electrode cells in a secondary battery according to a fifth embodiment of the present disclosure.

[0119] Figure 34 This is a view illustrating the process of assembling the current collector and the polarity unit according to the fifth embodiment of this disclosure.

[0120] Figure 35 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a fifth embodiment of the present disclosure.

[0121] Figure 36 This is a view illustrating a current collector in a secondary battery according to a sixth embodiment of the present disclosure.

[0122] Figure 37 This is a view illustrating a current collector in a secondary battery according to a sixth embodiment of the present disclosure.

[0123] Figure 38 This is a view illustrating the process of assembling the current collector and the polarity unit in the sixth embodiment of this disclosure.

[0124] Figure 39 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a sixth embodiment of the present disclosure.

[0125] Figure 40 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a sixth embodiment of the present disclosure.

[0126] Figure 41This is a view illustrating the current collector in a secondary battery according to the seventh embodiment of the present disclosure.

[0127] Figure 42 This is a view of the current collection unit of the current collector in a secondary battery according to the seventh embodiment of this disclosure.

[0128] Figure 43 This is a view of the electrode unit of the current collector in a secondary battery according to the seventh embodiment of this disclosure.

[0129] Figure 44 This is a view of the electrode unit of the current collector in a secondary battery according to the seventh embodiment of this disclosure.

[0130] Figure 45 This is a view illustrating the process of assembling the current collector and the pole unit according to the seventh embodiment of this disclosure.

[0131] Figure 46 yes Figure 45 A magnified view of a portion of the image.

[0132] Figure 47 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to the seventh embodiment of the present disclosure.

[0133] Figure 48 This is a view illustrating the current collector in a secondary battery according to the eighth embodiment of the present disclosure.

[0134] Figure 49 This is a view of the current collection unit of the current collector in a secondary battery according to the eighth embodiment of this disclosure.

[0135] Figure 50 This is a view of the electrode unit of the current collector in a secondary battery according to the eighth embodiment of this disclosure.

[0136] Figure 51 This is a view of the electrode unit of the current collector in a secondary battery according to the eighth embodiment of this disclosure.

[0137] Figure 52 This is a view illustrating the process of assembling the current collector and the pole unit according to the eighth embodiment of this disclosure.

[0138] Figure 53 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to the eighth embodiment of the present disclosure.

[0139] Figure 54 This is a view illustrating the current collector in a first modified secondary battery according to a first embodiment of the present disclosure.

[0140] Figure 55 and Figure 56 This is a view illustrating the current collector in a second modified secondary battery according to the first embodiment of the present disclosure.

[0141] Figure 57 This is a flowchart illustrating a method for manufacturing a secondary battery according to a first embodiment of the present disclosure.

[0142] Figure 58 This is a view illustrating a plurality of first electrode contacts and a plurality of second electrode contacts grouped separately in a secondary battery according to a first embodiment of the present disclosure.

[0143] Figure 59 This is a view illustrating a plurality of first electrode contacts and a plurality of second electrode contacts that have been initially welded in a secondary battery according to a first embodiment of the present disclosure.

[0144] Figure 60 It is a 3D diagram showing the current collector to be installed onto the electrode assembly.

[0145] Figure 61 This is a view illustrating a current collector disposed between a plurality of first electrode contacts and a plurality of second electrode contacts in a secondary battery according to a first embodiment of the present disclosure.

[0146] Figure 62 and Figure 63 This is a view illustrating a first electrode contact and a second electrode contact welded to a current collector in a secondary battery according to a first embodiment of the present disclosure.

[0147] Figure 64 This is a view illustrating a cover assembly connected to an electrode assembly in a secondary battery according to a first embodiment of the present disclosure.

[0148] Figure 65 It shows along Figure 64 The longitudinal section taken from line B-B' in the diagram.

[0149] Figure 66 This is a view illustrating the welding of a first electrode tab and a second electrode tab to a current collector in a first modified secondary battery according to a first embodiment of the present disclosure.

[0150] Figure 67 It shows along Figure 66 The longitudinal section cut by line S2-S2' in the middle.

[0151] Figure 68 The illustration shows a view of a second modified secondary battery according to a first embodiment of the present disclosure, in which a first electrode tab and a second electrode tab are welded to a current collector.

[0152] Figure 69 It shows along Figure 68 The longitudinal section cut by line S3-S3' in the middle.

[0153] Figure 70 The illustration shows a view of the first electrode tab and the second electrode tab of a second modified secondary battery according to the first embodiment of the present disclosure being welded to a current collector.

[0154] Figure 71 This is a view illustrating a current collector in a secondary battery according to a ninth embodiment of the present disclosure.

[0155] Figure 72 This is a view of the current collection unit of the current collector in a secondary battery according to the ninth embodiment of this disclosure.

[0156] Figure 73 This is a view of the electrode unit of the current collector in a secondary battery according to the ninth embodiment of this disclosure.

[0157] Figure 74 This is a view of the electrode unit of the current collector in a secondary battery according to the ninth embodiment of this disclosure.

[0158] Figure 75 This is a view illustrating the process of assembling the current collector and the pole unit according to the ninth embodiment of this disclosure.

[0159] Figure 76 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to the ninth embodiment of the present disclosure.

[0160] Figure 77 This is a view illustrating a current collector in a secondary battery according to a modified example of the ninth embodiment of this disclosure.

[0161] Figure 78 This is a view illustrating the current collector in a secondary battery according to the tenth embodiment of the present disclosure.

[0162] Figure 79 This is a view of the current collection unit of the current collector in a secondary battery according to the tenth embodiment of this disclosure.

[0163] Figure 80 This is a view of the electrode unit of the current collector in a secondary battery according to the tenth embodiment of this disclosure.

[0164] Figure 81 This is a view of the electrode unit of the current collector in a secondary battery according to the tenth embodiment of this disclosure.

[0165] Figure 82 This is a view illustrating the process of assembling the current collector and the pole unit according to the tenth embodiment of this disclosure.

[0166] Figure 83 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to the tenth embodiment of the present disclosure.

[0167] Figure 84 This is an exploded perspective view of a secondary battery according to the eleventh embodiment of the present disclosure.

[0168] Figure 85 It shows Figure 84 A three-dimensional view of the electrode assembly of the secondary battery.

[0169] Figure 86 This is a partial perspective view showing a secondary battery of a first modification according to the eleventh embodiment of the present disclosure.

[0170] Figure 87 This is a partial perspective view showing a second modified secondary battery according to the eleventh embodiment of the present disclosure.

[0171] Figure 88 This is a partial perspective view showing a third modified secondary battery according to the eleventh embodiment of the present disclosure. Detailed Implementation

[0172] Because this disclosure can be modified in various forms and has various embodiments, specific embodiments will be illustrated in the accompanying drawings and described in detail with reference to the drawings. However, this is not intended to limit this disclosure to a particular mode of practice, and it should be understood that all variations, equivalents, and substitutions that do not depart from the spirit and technical scope of this disclosure are included in this disclosure.

[0173] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. In this disclosure, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. It will also be understood that the terms “comprising,” “including,” “having,” etc., as used in this specification, are intended to specify the presence of stated features, integrals, steps, operations, elements, components, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof.

[0174] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that throughout the drawings, the same reference numerals refer to the same elements. Details of well-known configurations and functions may be omitted to avoid unnecessarily obscuring the essential points of the present disclosure. For the same reason, some elements are enlarged, omitted, or depicted schematically in the drawings.

[0175] The secondary battery according to the first embodiment of the present disclosure will be described below.

[0176] Figure 1 This is a view illustrating a secondary battery according to a first embodiment of the present disclosure. Figure 2 This is a view illustrating the separation of the cover assembly and electrode assembly of a secondary battery according to a first embodiment of the present disclosure.

[0177] Figure 3 This is a view illustrating an electrode assembly in a secondary battery according to a first embodiment of the present disclosure, wherein a plurality of first electrode contacts and a plurality of second electrode contacts are formed on the electrode portion. Figure 4A and Figure 4B This is a view illustrating the first electrode element and the second electrode element in a secondary battery according to a first embodiment of the present disclosure. Figure 5A and Figure 5B This is a view illustrating the third and fourth electrode elements in a secondary battery according to a first embodiment of the present disclosure.

[0178] like Figure 1 and Figure 2 As illustrated, the secondary battery 1000 according to an embodiment of the present disclosure includes a housing 1100, an electrode assembly 1200, a current collector 1300, and a cover assembly 1400.

[0179] The housing 1100 forms the external shape of the secondary battery 1000. The housing 1100 may define a space capable of accommodating the electrode assembly 1200 therein, and may have an opening on one surface of the housing 1100. In this embodiment, the housing 1100 has a cuboid shape, but is not limited thereto, and can be modified in various ways. The housing 1100 may be made of a rigid material capable of protecting the electrode assembly 1200 housed therein. For example, the housing 1100 may be made of a metal such as aluminum or stainless steel.

[0180] The electrolyte can be housed together with the electrode assembly 1200 in a cartridge 1100. The electrolyte may include lithium salts such as LiPF6 or LiBF4 in organic solvents such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), or dimethyl carbonate (DMC). The electrolyte may be a liquid, solid, or gel phase.

[0181] The electrode assembly 1200 is housed in the housing 1100. For example... Figure 3As illustrated, the electrode assembly 1200 includes an electrode portion 1210, a plurality of first electrode tabs 1220, and a plurality of second electrode tabs 1230. The plurality of first electrode tabs 1220 and the plurality of second electrode tabs 1230 are disposed on one end of the electrode portion 1210. The plurality of first electrode tabs 1220 are grouped and aligned with each other, and the plurality of second electrode tabs 1230 are grouped and aligned with each other. The aligned first electrode tabs 1220 and the aligned second electrode tabs 1230 are arranged so as not to overlap in the thickness direction (x-direction) and longitudinal direction (y-direction) of the electrode assembly 1200.

[0182] Specifically, the electrode portion 1210 includes a plurality of first electrode elements 1211, a plurality of second electrode elements 1212, a plurality of third electrode elements 1213, a plurality of fourth electrode elements 1214, and a separator.

[0183] Active materials can be applied to multiple first electrode elements 1211, multiple second electrode elements 1212, multiple third electrode elements 1213, and multiple fourth electrode elements 1214. The multiple first electrode elements 1211 and multiple second electrode elements 1212 can each be formed by applying an active material, such as a transition metal oxide, to a metal plate, such as an aluminum plate. The multiple first electrode elements 1211 and multiple second electrode elements 1212 can have the same polarity and can be positive electrode plates. The multiple third electrode elements 1213 and multiple fourth electrode elements 1214 can each be formed by applying an active material, such as graphite or carbon, to a metal plate, such as a copper plate or a nickel plate. The multiple third electrode elements 1213 and multiple fourth electrode elements 1214 can have the same polarity and can be negative electrode plates.

[0184] The separator is positioned between the plurality of first electrode elements to the fourth electrode elements 1211, 1212, 1213 and 1214 to prevent short circuits between the plurality of first electrode elements to the fourth electrode elements 1211, 1212, 1213 and 1214. The separator may be made of polyethylene, polypropylene, or composite materials thereof.

[0185] Electrode portion 1210 can be formed by positioning spacers between alternately arranged first electrode elements 1211 and third electrode elements 1213 and alternately arranged second electrode elements 1212 and fourth electrode elements 1214. In other words, in an embodiment, electrode portion 1210 can be formed such that one side of electrode portion 1210 is formed by stacking the first electrode element 1211, spacer, third electrode element 1213, and spacer in a listed order dozens to hundreds of times, and the other side of electrode portion 1210 is formed by stacking the second electrode element 1212, spacer, fourth electrode element 1214, and spacer in a listed order dozens or hundreds of times. In another embodiment, electrode portion 1210 can be formed by sequentially stacking the first electrode element 1211, spacer, third electrode element 1213, spacer, second electrode element 1212, spacer, fourth electrode element 1214, and spacer in a listed order, and then winding the stacked structure.

[0186] Although the electrode assembly 1200 is illustrated as including a single electrode portion 1210 in this embodiment, in another embodiment, the electrode assembly 1200 may include multiple electrode portions 1210. The multiple electrode portions 1210 may be electrically connected to each other.

[0187] First electrode tabs 1220, 1230, 1240, and 1250 without applied active material are formed at one end of a plurality of first to fourth electrode elements 1211, 1212, 1213, and 1214, respectively. In an embodiment, each of the electrode elements 1211, 1212, 1213, and 1214 and the corresponding electrode tab 1220, 1230, 1240, or 1250 can be integrally formed by cutting a predetermined portion of a single metal plate using a laser or the like, such that the electrode elements 1211, 1212, 1213, or 1214 and the electrode tabs 1220, 1230, 1240, or 1250 are retained. The plurality of electrode tabs 1220, 1230, 1240, and 1250 can be formed in a direction toward the cover assembly 1400.

[0188] Each first electrode tab in the first electrode tab 1220 can be formed at a first position of the corresponding first electrode element 1211, and each second electrode tab in the second electrode tab 1230 can be formed at a second position of the corresponding second electrode element 1212 (see...). Figure 4A and 4B Similarly, each third electrode tab in the third electrode tab 1240 can be formed at a third position of the corresponding third electrode element 1213, and each fourth electrode tab in the fourth electrode tab 1250 can be formed at a fourth position of the corresponding fourth electrode element 1214 (see...). Figure 5A and Figure 5B ).

[0189] Multiple first electrode elements 1211 and multiple third electrode elements 1213 can be stacked alternately, wherein corresponding spacers are inserted between adjacent electrode elements. The stack including multiple first electrode elements 1211 and multiple third electrode elements 1213 forms half of the electrode portion 1210.

[0190] Multiple second electrode elements 1212 and multiple fourth electrode elements 1214 can be stacked alternately, wherein corresponding spacers are inserted between adjacent electrode elements. The stack including multiple second electrode elements 1212 and multiple fourth electrode elements 1214 forms the remaining half of the electrode portion 1210.

[0191] A stack comprising multiple first electrode elements 1211 and multiple third electrode elements 1213 is connected to a stack comprising multiple second electrode elements 1212 and multiple fourth electrode elements 1214 in the thickness direction (x direction) of the electrode portion 1210. During the formation of the electrode assembly 1200, the multiple first electrode elements 1211 and multiple third electrode elements 1213 may be stacked before the multiple second electrode elements 1212 and multiple fourth electrode elements 1214 are stacked.

[0192] When multiple first to fourth electrode elements 1211, 1212, 1213, and 1214 are stacked, multiple first electrode tabs 1220 overlap each other at a first position, and multiple second electrode tabs 1230 overlap each other at a second position. In other words, multiple first electrode tabs 1220 are grouped at the first position, and multiple second electrode tabs 1230 are grouped at the second position. The first and second positions are spaced apart from each other on the electrode elements. The grouped multiple first electrode tabs 1220 and the grouped multiple second electrode tabs 1230 may be spaced apart in the thickness direction (x-direction) and longitudinal direction (y-direction) of the electrode assembly 1200.

[0193] Multiple first electrode contacts 1220 in a group are initially welded to each other, and multiple second electrode contacts 1230 in a group are initially welded to each other.

[0194] Multiple first electrode tabs 1220 and multiple second electrode tabs 1230 are electrode tabs with the same polarity and are initially welded at corresponding positions spaced apart in the thickness and longitudinal directions of the electrode assembly 1200 to achieve stable welding of a large number of electrode tabs, and then secondary welding is performed on the current collector. In other words, although a single electrode tab is formed on each electrode element, by changing the position of the electrode tabs formed on the corresponding electrode elements, two groups of electrode tabs with the same polarity but different positions are formed after stacking the electrode elements. In another embodiment, two or more electrode tabs can be formed at different positions on the same polarity side.

[0195] When multiple first to fourth electrode elements 1211, 1212, 1213, and 1214 are stacked, multiple third electrode tabs 1240 overlap each other at a third position, and multiple fourth electrode tabs 1250 overlap each other at a fourth position. In other words, the multiple third electrode tabs 1240 are grouped at the third position, and the multiple fourth electrode tabs 1250 are grouped at the fourth position. The third and fourth positions are spaced apart from each other on the electrode elements. The grouped multiple third electrode tabs 1240 and the grouped multiple fourth electrode tabs 1250 may be spaced apart in the thickness direction (x-direction) and longitudinal direction (y-direction) of the electrode assembly 1200.

[0196] The multiple third electrode contacts 1240 and the multiple fourth electrode contacts 1250 are electrode contacts with the same polarity.

[0197] Multiple electrode contacts 1220, 1230, 1240 and 1250 that overlap in corresponding positions can be joined together by ultrasonic welding, laser welding or other methods to facilitate current flow.

[0198] The current collector 1300 can be disposed on the upper end of the electrode portion 1210. Electrode contacts 1220 and 1230 can be bent to the upper surface of the current collector 1300 and welded to the upper surface of the current collector 1300, so that the current collector 1300 can be connected to the electrode contacts 1220 and 1230.

[0199] In related technologies, welding is performed after the current collector is placed on the electrode contacts, and therefore requires high laser output to transfer heat to the electrode contacts located below the current collector. However, in this disclosure, the electrode contacts are disposed on the upper surface of the current collector, thereby enabling welding with a relatively low output. Since it is not even necessary to melt the lower portion of the current collector in this disclosure, the thickness of the current collector can be increased to protect the separators disposed in the electrode portion. Therefore, damage to the separators can be prevented, and the durability of the secondary battery can be improved.

[0200] One side of the current collector 1300 can be connected to the electrode terminals. The electrode contacts 1220 and 1230 of the electrode section 1210 can be electrically connected to the electrode terminals through the current collector 1300.

[0201] The current collector 1300 can be configured as two current collectors 1300. The material of each current collector 1300 can be the same as the material of the first electrode contact 1220 and the second electrode contact 1230 or the third electrode contact 1240 and the fourth electrode contact 1250. In other words, each current collector 1300 can be made of aluminum, or it can be made of copper or nickel.

[0202] Detailed specifications of the collector 1300 will be provided later.

[0203] The cover assembly 1400 seals the opening of the housing 1100 that contains the electrode assembly 1200. The cover assembly 1400 includes a cover plate 1410 and electrode terminals 1420 and 1420a.

[0204] The cover plate 1410 may have a plate shape that covers the opening of the box 1100. The cover plate 1410 may have a shape that corresponds to the shape of the opening of the box 1100. The cover plate 1410 may be made of the same material as the box 1100 and may be fixed to the box 1100 by a method such as laser welding.

[0205] The cover plate 1410 may have a vent 1411 and an electrolyte injection port 1412. The vent 1411 opens when the internal pressure of the housing 1100 exceeds a reference value. In this embodiment, the vent 1411 is formed in the cover plate 1410; however, in other embodiments, the vent 1411 may be formed in the housing 1100. Electrolyte can be injected into the housing 1100 through the electrolyte injection port 1412.

[0206] Electrode terminals 1420 and 1420a may be formed to protrude from cover plate 1410. Electrode terminals 1420 and 1420a are electrically connected to corresponding electrode contacts 1220, 1230, 1240 and 1250 respectively via current collector 1300. Electrode terminals 1420 and 1420a may each have a plate shape in the form of a circle or a rectangle.

[0207] Through holes can be formed in each of electrode terminals 1420 and 1420a. A current collector protrusion 1321 can be inserted into the through hole. After the current collector protrusion 1321 is inserted into the through hole, the outer peripheral surface of the end of the current collector protrusion 1321 and the inner peripheral surface of the end of the through hole can be welded to each other.

[0208] Insulators can be positioned between electrode terminals 1420 and 1420a and cover plate 1410, respectively. The insulators electrically insulate electrode terminals 1420 and 1420a from cover plate 1410.

[0209] In the following text, a current collector for a secondary battery according to a first embodiment of the present disclosure will be described.

[0210] Figure 6 This is a view illustrating a current collector in a secondary battery according to a first embodiment of the present disclosure. Figure 7 This is a view illustrating a current collector in a secondary battery according to a first embodiment of the present disclosure. Figure 8 It is along Figure 7 A cross-sectional view taken by line A-A'.

[0211] Figure 9 This is a view illustrating the current collector unit in a secondary battery according to a first embodiment of the present disclosure. Figure 10A and Figure 10B This is a view illustrating the electrode cells in a secondary battery according to a first embodiment of the present disclosure. Figure 11 This is a view illustrating the process of assembling the current collector and the pole unit in the first embodiment of this disclosure.

[0212] Figure 12 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a first embodiment of the present disclosure. Figure 13 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a modified example of the first embodiment of the present disclosure.

[0213] like Figures 6 to 8 As illustrated, the current collector 1300 may include a current collector unit 1310 and an electrode unit 1320. The current collector unit 1310 may be connected to multiple electrode contacts 1220 and 1230. The electrode unit 1320 may be connected to corresponding electrode terminals.

[0214] Depending on the arrangement of the electrode contacts and the connection configuration of the electrode portion, the current collector 1310 can have various shapes.

[0215] For example, such as Figure 6 As illustrated, the current collector 1310 may have a rectangular shape extending along the longitudinal direction (y-direction) of the electrode assembly 1200. The current collector 1310 may include a connecting portion 1313, a first current collector portion 1311, and a second current collector portion 1312 continuously arranged along the longitudinal direction of the rectangular shape. The connecting portion 1313, the first current collector portion 1311, and the second current collector portion 1312 may be made of the same material and may be integrally formed.

[0216] The first current collector 1311 can be soldered to a plurality of first electrode contacts 1220. The plurality of first electrode contacts 1220 can be bent onto the upper surface of the first current collector 1311 and soldered thereto. The second current collector 1312 can be soldered to a plurality of second electrode contacts 1230. The plurality of second electrode contacts 1230 can be bent onto the upper surface of the second current collector 1312 and soldered thereto. The first current collector 1311 and the second current collector 1312 can have a predetermined height h1. Specifically, the height of each of the first current collector 1311 and the second current collector 1312 can be in the range of 0.5 mm to 3.0 mm.

[0217] The connecting portion 1313 can be connected to one side of the first current collector portion 1311. The second current collector portion 1312 can be connected to the remaining side of the first current collector portion 1311. Since the first current collector unit 1311 and the second current collector unit 1312 are arranged continuously in the longitudinal direction without overlapping, the plurality of first electrode contacts 1220 and the plurality of second electrode contacts 1230 will not interfere with each other when they are respectively soldered to the first current collector unit 1311 and the second current collector unit 1312.

[0218] The connecting portion 1313 can be formed to have the same thickness as the first current collector portion 1311 and the second current collector portion 1312. The thickness of the connecting portion 1313 can be in the range of 0.5 mm to 3.0 mm. The radius of curvature of the edge of the upper surface of the current collector unit 1310 can be in the range of 0.25 mm to 0.35 mm.

[0219] The connection part 1313 can be connected to the pole unit 1320.

[0220] An opening can be formed in the connecting part 1313.

[0221] A stop portion 1314 may be provided on the upper surface of the connecting portion 1313. The stop portion 1314 may protrude from the upper surface of the connecting portion 1313 by a predetermined height h2. When the current collector 1300 is connected to another component, the lower limit position of the component to be connected to the current collector 1300 may be defined by the stop portion 1314. Since the electrode contacts are disposed on and welded to the first current collector portion 1311 and the second current collector portion 1312 of the current collector unit 1310, the welded portions each form a predetermined thickness. If the thicknesses of the welded portions on the first current collector portion 1311 and the second current collector portion 1312 are not equal, the component connected to the current collector 1300 may not be properly leveled. Such improper leveling may reduce the airtightness of the assembled secondary battery or cause assembly defects. When the stop 1314 is provided on the upper surface of the collector 1300, the components assembled to the collector 1300 can be horizontally aligned.

[0222] The height h2 of the stop portion 1314 can be equal to or greater than the height of the plurality of first electrode contacts 1220 and the plurality of second electrode contacts 1230 welded to the upper surface of the current collector unit 1310 of the current collector 1300. The height h2 of the stop portion 1314 can be calculated by the following formula: h2 = A × 0.005 × B / C, where A is the thickness of the electrode assembly 1200, B is the length of the electrode contacts, and C is the number of groups of electrode contacts to be welded to the current collector. As the number of first electrode contacts 1220 and second electrode contacts 1230 increases, that is, as the number of electrode assemblies 1200 (in) increases, the height of the stop portion 1314 can be greater than the height of the plurality of first electrode contacts 1220 and second electrode contacts 1230 welded to the current collector unit 1310 of the current collector 1300. Figure 2 As the thickness in the x-direction increases, the height h2 of the stop portion 1314 can also increase. The height h2 of the stop portion 1314 can be 1% to 5% of the thickness of the electrode assembly 1200, and for example, it can be 2.5%. In the two current collectors 1300 provided on the electrode portion 1210, the stop portion 1314 can have the same height. Furthermore, as the number of electrode tabs grouped and welded to the current collector 1300 increases, the height h2 of the stop portion 1314 can decrease.

[0223] The stop portion 1314 may have a square plate shape, a rectangular plate shape, or a disc shape. The upper surface of the stop portion 1314 may be formed as a flat surface to support the component to be assembled thereon, and may have a predetermined area. The cross-sectional area of ​​the stop portion 1314 may be 3% to 6% of the upper surface of the current collector unit 1310. The stop portion 1314 may be integrally formed with the connecting portion 1313.

[0224] The stop portion 1314 can protrude upward from the upper surface of the connecting portion 1313, and the height h2 of the stop portion 1314 can be less than the thickness of the current collecting unit 1310. Specifically, the height h2 of the stop portion 1314 can be 30% to 50% of the height h1 of the end of the current collecting unit 1310, i.e., the end of the first current collecting portion 1311 or the second current collecting portion 1312. Due to the stop portion 1314, a stepped structure of the current collecting unit 1310 can be formed.

[0225] like Figure 9 As illustrated, an opening can be formed in the stop portion 1314. The opening can be formed to pass through the center of the stop portion 1314. In this case, the opening of the stop portion 1314 can be connected to the opening of the connecting portion 1313 to form a continuous opening 1315. The current collecting protrusion 1321 of the pole unit 1320 can be inserted through the opening 1315.

[0226] A recessed region 1317 may be formed in the lower surface of the current collecting unit 1310. The recessed region 1317 and the opening 1315 are joined together in the thickness direction (z-direction) of the connecting portion 1313 to penetrate the connecting portion 1313. The recessed region 1317 may have a rectangular plate shape and may define a free space above the lower surface of the current collecting unit 1310. The recessed region 1317 may be formed in a portion of the lower surface of the connecting portion 1313 and the lower surface of the first current collecting portion 1311. The depth d1 of the recessed region 1317 may be 30% to 50% of the height h1 of the end of the current collecting unit 1310.

[0227] The electrode unit 1320 can be connected to the current collector unit 1310. One side of the electrode unit 1320 can be connected to the current collector unit 1310, and the other side of the electrode unit 1320 can be connected to the corresponding electrode terminal. The electrode contacts 1220 and 1230 of the electrode portion 1210 can be electrically connected to the electrode terminal by the electrode unit 1320.

[0228] The electrode unit 1320 can be electrically connected to a corresponding electrode terminal. The material of the electrode unit 1320 can be the same as or different from that of the current collector unit 1310. For example, both the current collector unit 1310 and the electrode unit 1320 can be made of aluminum. Alternatively, the current collector unit 1310 can be made of copper, and the electrode unit 1320 can be made of aluminum. According to this disclosure, since the current collector unit 1310 and the electrode unit 1320 are formed as separate components, the flexibility in selecting the materials and dimensions of the components can be increased.

[0229] like Figure 10A and Figure 10BAs illustrated, the electrode unit 1320 may include a current collector protrusion 1321 and a support portion 1322. The current collector protrusion 1321 may have a cylindrical shape with a predetermined height hc. The current collector protrusion 1321 may be electrically connected to a corresponding electrode terminal. The current collector protrusion 1321 may be inserted into the opening 1315 of the connecting portion 1313 and the stop portion 1314. In order to stably support the component mounted on the current collector protrusion 1321 on the stop portion 1314, the stop portion 1314 may have a predetermined area. The area of ​​the horizontal cross-section of the stop portion 1314 may be 2 to 5 times the area of ​​the horizontal cross-section of the current collector protrusion 1321. Since the cross-sectional area of ​​the stop portion 1314 is formed to be larger than the cross-sectional area of ​​the current collector protrusion 1321, the component can be stably supported.

[0230] To facilitate the connection between the current collecting protrusion 1321 and the component, the height hc of the current collecting protrusion 1321 can be formed to be greater than the height h2 of the stop portion 1314 within a predetermined range. Specifically, the height h2 of the stop portion 1314 can be 10% to 20% of the height hc of the current collecting protrusion 1321, and for example, it can be 15% of the height hc of the current collecting protrusion 1321. When the height h2 of the stop portion 1314 is greater than 20% of the height hc of the current collecting protrusion 1321, the height difference between the upper surface of the stop portion 1314 and the upper surfaces of the first current collecting portion 1311 and the second current collecting portion 1312 increases, making it difficult to stably support the component.

[0231] When the current collector 1300 is used as a negative current collector, the upper end of the current collector protrusion 1321, which is made of copper, can be plated with nickel. For example... Figure 10B As shown, the height of the nickel plating 1326 can be 1.5 mm to 2.5 mm from the upper end of the current collector protrusion 1321. The height of the nickel plating 1326 can be 30% to 50% of the height of the current collector protrusion 1321. The thickness of the nickel plating 1326 can be in the range of 2 μm to 4 μm. Because the upper end of the current collector protrusion 1321 is plated with nickel, the weld strength when the current collector protrusion 1321 is soldered to the electrode terminal can be further improved.

[0232] The support portion 1322 can be connected to the lower end of the current collector protrusion 1321 and can have a rectangular plate shape. The support portion 1322 can support the current collector protrusion 1321 such that when the pole unit 1320 is connected to the current collector unit 1310, the current collector protrusion 1321 is perpendicular to the current collector unit 1310. The current collector protrusion 1321 and the support portion 1322 can be integrally formed. The support portion 1322 can be received in the recessed region 1317 of the current collector unit 1310. The height h3 of the support portion 1322 can be the same as the depth d1 of the recessed region. In other words, the lower surface of the support portion 1322 and the lower surface of the current collector unit 1310 can be flush with each other (see...). Figure 11 ).

[0233] After the support portion 1322 is assembled into the recessed region 1317 of the current collector unit 1310, the support portion 1322 can be joined to the current collector unit 1310 by welding. Welding can be performed on the lower surface of the support portion 1322. Due to welding, a welding region A or a welding region B can be formed on the lower surface of the support portion 1322.

[0234] like Figure 12 As illustrated in the figure, in this embodiment, the welding area can be formed on the outer periphery (welding area A) of the lower surface of the support portion 1322. The support portion 1322 overlaps with the current collector 1310. Although the plate-shaped current collector 1310 has a predetermined thickness h1, the thickness of the current collector 1310 is reduced in the portion where the recessed area 1317 receiving the support portion 1322 is formed. Therefore, when the laser output is relatively high during welding, welding marks may even form on the upper surface of the current collector 1310, and the flatness of the upper surface may deteriorate. To prevent the above problems, welding can be performed only on the outer periphery (welding area A) of the support portion 1322 where the thickness of the current collector 1310 is ensured.

[0235] In the modified example, a welding area (welding area B) can be formed on the entire lower surface of the support portion 1322 (see [reference]). Figure 13 To stably fix the pole unit 1320 to the current collector unit 1310, the entire lower surface of the support portion 1322 can be welded to increase the welding area. In this case, the laser output on the outer periphery (first welding area B-1) of the lower surface of the support portion 1322 can be higher than the laser output on the inner side (second welding area B-2) of the lower surface of the support portion 1322. Since the thickness of the portion of the current collector unit 1310 adjacent to the inner side (second welding area B-2) of the lower surface of the support portion 1322 is smaller than the thickness at the outer periphery, the laser output can be adjusted to a lower level.

[0236] According to this disclosure, sufficient welding area can be ensured by the rectangular support portion 1322, so that the current collecting protrusion 1321 can be stably connected to the current collecting unit 1310. In addition, since the support portion 1322 is formed in the shape of a rectangular plate and is received in the recessed region 1317, undesirable rotation of the current collecting protrusion 1321 can be prevented.

[0237] The width of current collector 1300 can be 0.3 to 0.8 times the thickness of electrode assembly 1200. Current collector 1300 can have a thickness of 0.5 mm to 3.0 mm.

[0238] An insulator can be disposed below the current collector 1300. The insulator can be an insulating plate or an insulating film. The insulator can more reliably protect the electrode contacts 1220 and 1230 and the electrode portion 1210.

[0239] After the pole unit 1320 is soldered to the current collector unit 1310, an insulator can be applied or attached to the lower surface of the current collector unit 1310 with a predetermined thickness.

[0240] In this embodiment, the structure in which the connecting portion 1313 is connected to the pole unit 1320 has been described; however, this disclosure is not limited thereto, and the connecting portion 1313 may have various shapes and may be connected to the pole unit 1320 in various ways.

[0241] In the following text, a current collector for a secondary battery according to a second embodiment of the present disclosure will be described. Descriptions of elements identical to those in the first embodiment will be omitted or briefly described.

[0242] Figure 14 This is a view illustrating the connection portion and electrode units in the current collector of a secondary battery according to a second embodiment of the present disclosure. Figure 15 It is along Figure 14 A cross-sectional view taken by line B–B'.

[0243] Figure 16 This is a view illustrating the current collector unit in a secondary battery according to a second embodiment of the present disclosure. Figure 17A and Figure 17B This is a view illustrating the electrode cells in a secondary battery according to a second embodiment of the present disclosure. Figure 18 This is a view illustrating the process of assembling the current collector and the pole unit in the second embodiment of this disclosure.

[0244] Figure 19 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a second embodiment of the present disclosure.

[0245] like Figure 14As illustrated, the current collector 2300 may include a current collector unit 2310 and an electrode unit 2320. The current collector unit 2310 may be connected to multiple electrode contacts 1220 and 1230. The electrode unit 2320 may be connected to corresponding electrode terminals.

[0246] The current collector 2310 may have a rectangular shape extending along the longitudinal direction (y direction) of the electrode assembly 1200, and may include a connecting portion 2313, a first current collector 2311, and a second current collector 2312 arranged in sequence. The connecting portion 2313, the first current collector 2311, and the second current collector 2312 may be made of the same material and may be integrally formed.

[0247] The first current collector portion 2311 can be soldered to a plurality of first electrode contacts 1220. The second current collector portion 2312 can be soldered to a plurality of second electrode contacts 1230. The connecting portion 2313 can be formed to have the same thickness as the first current collector portion 2311 and the second current collector portion 2312. The thickness of the connecting portion 2313 can be in the range of 0.5 mm to 3.0 mm. The radius of curvature of the edge of the upper surface of the current collector 2300 can be in the range of 0.25 mm to 0.35 mm.

[0248] The connection part 2313 can be connected to the pole unit 2320.

[0249] A stop portion 2314 may be provided on the upper surface of the connecting portion 2313. The stop portion 2314 may protrude from the upper surface of the connecting portion 2313 by a predetermined height h2. When the current collector 2300 is connected to another component, the lower limit position of the component to be connected to the current collector 2300 may be defined by the stop portion 2314. Using the stop portion 2314 provided on the upper surface of the current collector 2300, the component assembled to the current collector 2300 may be horizontally aligned.

[0250] The height h2 of the stop portion 2314 can be 1% to 5% of the thickness of the electrode assembly 1200, and for example, it can be 2.5%. In the two current collectors 2300 disposed on the electrode portion 1210, the stop portion 2314 can have the same height. The height h2 of the stop portion 2314 can be calculated using the following formula: h2 = A × 0.005 × B / C, where A is the thickness of the electrode assembly 1200, B is the length of the electrode tab, and C is the number of groups of electrode tabs to be welded to the current collector.

[0251] The stop portion 2314 may have a square plate shape, a rectangular plate shape, or a disc shape. The upper surface of the stop portion 2314 may be formed as a flat surface to support the component to be assembled thereon, and may have a predetermined area. The cross-sectional area of ​​the stop portion 2314 may be 3% to 6% of the upper surface of the current collector unit 2310. The stop portion 2314 may be integrally formed with the connecting portion 2313.

[0252] The stop portion 2314 can protrude upward from the upper surface of the connecting portion 2313, and the height h2 of the stop portion 2314 can be equal to or less than the thickness of the current collecting unit 2310. Specifically, the height h2 of the stop portion 2314 can be 30% to 100% of the height h1 of the end of the current collecting unit 2310, i.e., the end of the first current collecting portion 2311 or the second current collecting portion 2312. Due to the stop portion 2314, a stepped structure of the current collecting unit 2310 can be formed.

[0253] like Figure 16 As shown in the figure, an opening 2315 may be formed in the stop portion 2314. The opening 2315 may be formed to pass through the center of the stop portion 2314. The current collecting protrusion 2321 of the pole unit 2320 may pass through the opening 2315.

[0254] A recessed region 2317 may be formed in the lower surface of the current collecting unit 2310. The recessed region 2317 may have a disc-shaped or rectangular plate-shaped shape, and may define an empty space above the lower surface of the connecting portion of the current collecting unit 2310. The location where the recessed region 2317 is formed may be below the stop portion 2314. The cross-sectional area of ​​the recessed region 2317 may be smaller than the cross-sectional area of ​​the stop portion 2314. The depth d1 of the recessed region 2317 may be equal to the height h1 of the end of the current collecting unit 2310. Therefore, the recessed region 2317 may be integral with the opening 2315 formed in the connecting portion 2313. The opening 2315 and the recessed region 2317 penetrate the connecting portion 2313 in the thickness direction (z direction).

[0255] The cross-sectional area of ​​the recessed region 2317 can be larger than the cross-sectional area of ​​the opening 2315 of the stop portion 2314. That is, the upper surface of the recessed region 2317 can be the lower surface of the stop portion 2314. Below the opening 2315 of the stop portion 2314, the recessed region 2317 can be formed to have a larger cross-sectional area than the opening 2315 of the stop portion 2314.

[0256] The electrode unit 2320 can be connected to the current collector unit 2310, and the electrode contacts 1220 and 1230 of the electrode portion 1210 can be electrically connected to the corresponding electrode terminals. The material of the electrode unit 2320 can be the same as or different from the material of the current collector unit 2310.

[0257] like Figure 17A and Figure 17B As illustrated, the electrode unit 2320 may include a current collector protrusion 2321 and a support portion 2322. The current collector protrusion 2321 may have a cylindrical shape with a predetermined height hc. The current collector protrusion 2321 may be electrically connected to a corresponding electrode terminal. The current collector protrusion 2321 may be inserted into the opening 2315 of the stop portion 2314. The diameter of the current collector protrusion 2321 may be less than or equal to the inner diameter of the opening 2315.

[0258] To ensure that the component mounted on the manifold protrusion 2321 is stably supported on the stop 2314, the stop 2314 may have a predetermined area. The area of ​​the horizontal cross-section of the stop 2314 may be 2 to 5 times the area of ​​the horizontal cross-section of the manifold protrusion 2321. Because the cross-sectional area of ​​the stop 2314 is formed to be larger than the cross-sectional area of ​​the manifold protrusion 2321, the component can be stably supported.

[0259] To facilitate the connection between the current collecting protrusion 2321 and the component, the height hc of the current collecting protrusion 2321 can be formed to be greater than the height h2 of the stop portion 2314 within a predetermined range. Specifically, the height h2 of the stop portion 2314 can be 15% to 35% of the height hc of the current collecting protrusion 2321, and is preferably 25%. When the height h2 of the stop portion 2314 is greater than 20% of the height hc of the current collecting protrusion 2321, the height difference between the upper surface of the stop portion 2314 and the upper surface of the first current collecting portion 2311 and the upper surface of the second current collecting portion 2312 increases, thereby making it difficult to stably support the component.

[0260] When the current collector 2300 is used as a negative current collector, the upper end of the current collector protrusion 2321, which is made of copper, can be plated with nickel. For example... Figure 17B As shown, the height of the nickel plating 2326 can be 1.5 mm to 2.5 mm from the upper end of the current collector protrusion 2321. The height of the nickel plating 2326 can be 30% to 50% of the height of the current collector protrusion 2321. The thickness of the nickel plating 2326 can be in the range of 2 μm to 4 μm. Because the upper end of the current collector protrusion 2321 is plated with nickel, the weld strength when the current collector protrusion 2321 is soldered to the electrode terminal can be further improved.

[0261] The support portion 2322 can be connected to the lower end of the current collecting protrusion 2321 and can have a disc-shaped or rectangular plate-shaped form. The shape of the support portion 2322 can be the same as the shape of the recessed region 2317. The support portion 2322 can support the current collecting protrusion 2321 such that when the pole unit 2320 is connected to the current collecting unit 2310, the current collecting protrusion 2321 is perpendicular to the current collecting unit 2310. The current collecting protrusion 2321 and the support portion 2322 can be integrally formed. The peripheral edge of the upper end of the support portion 2322 can be rounded.

[0262] The support portion 2322 can be received in the recessed region 2317 of the current collecting unit 2310. The diameter of the support portion 2322 can be less than or equal to the diameter of the recessed region 2317. The cross-sectional area of ​​the support portion 2322 can be in the range of 150% to 300% of the cross-sectional area of ​​the current collecting protrusion 2321. In addition, the height h3 of the support portion 2322 can be less than the depth d1 of the recessed region 2317. In other words, when the support portion 2322 is received in the recessed region 2317, the lower surface of the support portion 2322 can be positioned inside the lower surface of the current collecting unit 2310, that is, above the lower surface of the current collecting unit 2310 (see...). Figure 18 Furthermore, the lower surface of the pole unit 2320 (i.e., the lower surface of the support portion 2322) is lower than the upper surface of the current collector unit 2310, making the connection between the pole unit 2320 and the current collector unit 2310 more stable.

[0263] Since the diameter of the current collecting protrusion 2321 is smaller than the inner diameter of the opening 2315 of the stop portion 2314 and the diameter of the support portion 2322 is smaller than the diameter of the recessed region 2317, gaps can be formed between the current collecting protrusion 2321 and the opening 2315, and between the support portion 2322 and the recessed region 2317, when the current collecting unit 2310 is connected to the pole unit 2320. Furthermore, the peripheral edge of the upper end of the support portion 2322 is rounded. Therefore, when the support portion 2322 is fitted into the recessed region 2317, it facilitates the insertion of the support portion 2322.

[0264] After the support portion 2322 is fitted into the recessed region 2317 of the current collector unit 2310, the support portion 2322 can be joined to the current collector unit 2310 by welding. Welding can be performed on the peripheral region of the lower surface of the support portion 2322. Due to welding, a welded region A can be formed on the lower surface of the support portion 2322.

[0265] like Figure 19As illustrated in the figure, in this embodiment, the welding area is formed at the outer periphery (welding area A) of the lower surface of the support portion 2322. The support portion 2322 can be positioned at a predetermined distance higher than the lower end of the connecting portion 2313, so that even if welding burrs are generated, the welding burrs will not protrude downward from the lower surface of the current collector 2310.

[0266] According to this disclosure, a sufficient welding area can be ensured by using a support portion 2322 having a disc-shaped or rectangular shape, so that the current collection protrusion 2321 can be stably connected to the current collection unit 2310. Furthermore, when the support portion 2322 is formed into a rectangular plate shape and received in the recessed region 2317, undesirable rotation of the current collection protrusion 2321 can be prevented.

[0267] The width of current collector 2300 can be 0.3 to 0.8 times the thickness of electrode assembly 1200. Current collector 2300 can have a thickness of 0.5 mm to 3.0 mm.

[0268] An insulator may be provided below the current collector 2300. The insulator may be an insulating plate or an insulating film. The insulator can more reliably protect the electrode contacts 1220 and 1230 as well as the electrode portion 1210.

[0269] After the pole unit 2320 is soldered to the current collector unit 2310, an insulator can be applied or attached to the lower surface of the current collector 2300 with a predetermined thickness.

[0270] In the following description, the current collector of the secondary battery according to the third embodiment of this disclosure will be described. Descriptions of elements that are the same as those in the first or second embodiment are omitted or simplified.

[0271] Figure 20 This is a view illustrating a current collector in a secondary battery according to a third embodiment of the present disclosure. Figure 21 It is along Figure 20 A cross-sectional view taken by line C–C'.

[0272] Figure 22 This is a view illustrating the current collector unit in a secondary battery according to a third embodiment of the present disclosure. Figure 23A and Figure 23B This is a view illustrating the electrode cells in a secondary battery according to a third embodiment of the present disclosure. Figure 24 This is a view illustrating the process of assembling a current collector unit and a polar unit together according to a third embodiment of the present disclosure.

[0273] Figure 25 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a third embodiment of the present disclosure.

[0274] like Figure 20 and Figure 21 As illustrated, the current collector 3300 may include a current collector unit 3310 and a current collector unit 3320. The current collector unit 3310 may include a first current collector section 3311, a second current collector section 3312, and a connection section 3313.

[0275] The current collector 3310 may have a rectangular shape extending along the longitudinal direction (y-direction) of the electrode assembly 1200. The current collector 3310 may be configured such that the connecting portion 3313, the first current collector portion 3311, and the second current collector portion 3312 are continuously arranged along the longitudinal direction of the rectangular shape. The height of each of the first current collector portion 3311 and the second current collector portion 3312 may be in the range of 0.5 mm to 3.0 mm. The radius of curvature of the edge of the upper surface of the current collector 3300 may be from 0.25 mm to 0.35 mm.

[0276] An opening 3315a may be formed in the connecting portion 3313.

[0277] A stop portion 3314 may be provided on the upper surface of the connecting portion 3313. The stop portion 3314 can protrude from the upper surface of the connecting portion 3313 by a predetermined height h2. The height h2 of the stop portion 3314 can be calculated by the following formula: h2=A×0.005×B / C, where A is the thickness of the electrode assembly 1200, B is the length of the electrode tab, and C is the number of groups of electrode tabs to be welded to the current collector. As the number of groups of electrode tabs to be welded to the current collector increases, the height h2 of the stop portion 3314 can decrease. The height h2 of the stop portion 3314 can be equal to or greater than the height of the plurality of first electrode tabs 1220 and the plurality of second electrode tabs 1230 welded to the upper surface of the current collector 3300. As the number of first electrode tabs 1220 and second electrode tabs 1230 increases, that is, as the thickness of the electrode assembly 1200 (in Figure 2 As the thickness in the x-direction increases, the height h2 of the stop portion 3314 can also be increased. The height h2 of the stop portion 3314 can be 1% to 5% of the thickness of the electrode assembly 1200, and for example, it can be 2.5%. In the two current collectors 3300 provided on the electrode portion 1210, the stop portion 3314 can have the same height.

[0278] The stop portion 3314 may have a square plate shape, a rectangular plate shape, or a disc shape. In this embodiment, the case where the stop portion 3314 has a disc shape will be described. The upper surface of the stop portion 3314 may be formed as a flat surface to support the component to be assembled thereon, and may have a predetermined area. The stop portion 3314 may be integrally formed with the connecting portion 3313.

[0279] The stop portion 3314 can protrude upward from the upper surface of the connecting portion 3313, and the height h2 of the stop portion 3314 can be less than the thickness of the current collecting unit 3310. Specifically, the height h2 of the stop portion 3314 can be 30% to 50% of the height h1 of the end of the first current collecting portion 3311 or the second current collecting portion 3312. Due to the stop portion 3314, a stepped structure of the current collecting unit 3310 can be formed (see...). Figure 21 ).

[0280] like Figure 22 As illustrated, an opening 3315b may be formed in the stop portion 3314. The opening 3315b may be formed to pass through the center of the stop portion 3314. In this case, the opening 3315b of the stop portion 3314 may be connected to the opening 3315a of the connecting portion 3313 to form a continuous opening 3315. The support portion 3322 of the pole unit 3320 may be inserted through the opening 3315. In this embodiment, the recessed region may be formed to have the same diameter as the opening 3315, and therefore, the recessed region may be integral with the opening 3315 formed in the connecting portion 3313.

[0281] The electrode unit 3320 can be electrically connected to a corresponding electrode terminal. The material of the electrode unit 3320 can be the same as or different from that of the current collector unit 3310. For example, both the current collector unit 3310 and the electrode unit 3320 can be made of aluminum. Alternatively, the current collector unit 3310 can be made of copper, and the electrode unit 3320 can be made of aluminum. According to this disclosure, since the current collector unit 3310 and the electrode unit 3320 are formed as separate components, flexibility in selecting the materials and dimensions of the components can be increased.

[0282] The pole unit 3320 may include a current collector protrusion 3321 and a support portion 3322 (see [link]). Figure 23A and Figure 23B The current collector protrusion 3321 can have a cylindrical shape with a predetermined height hc. The current collector protrusion 3321 can be electrically connected to the corresponding electrode terminal. The current collector protrusion 3321 can be supported by the support portion 3322 and can be connected to the current collector unit 3310. The support portion 3322 can be fitted into the opening 3315 of the connecting portion 3313 and the stop portion 3314, and can be fixed in a way that it is in close contact with the inner wall of the opening 3315. In order to allow the component fitted on the current collector protrusion 3321 to be stably supported on the stop portion 3314, the stop portion 3314 can have a predetermined area. When the current collector 3300 is used as a negative current collector, the upper end of the current collector protrusion 3321, which is made of copper, can be electroplated with nickel to form a nickel plating layer 3326, such as Figure 23B As shown.

[0283] To facilitate the connection between the current collecting protrusion 3321 and the component, the height hc of the current collecting protrusion 3321 can be formed to be greater than the height h2 of the stop portion 3314 within a predetermined range. Specifically, the height h2 of the stop portion 3314 can be 10% to 20% of the height hc of the current collecting protrusion 3321, and for example, it can be 15%.

[0284] The support portion 3322 can be connected to the lower end of the collecting protrusion 3321, and can have a square plate shape, a rectangular plate shape, or a disc shape. The support portion 3322 can have a shape corresponding to the shape of the opening 3315. The cross-sectional area of ​​the opening 3315 can also be square, rectangular, or circular.

[0285] The support portion 3322 can extend from the lower surface of the connecting portion 3313 to a height corresponding to the upper surface of the stop portion 3314 provided on the connecting portion 3313. The lower surface of the support portion 3322 can be flush with the lower surface of the connecting portion 3313. In addition, the upper surface of the support portion 3322 can be flush with the upper surface of the stop portion 3314.

[0286] The area of ​​the continuous surface formed by the upper surface of the stop portion 3314 and the upper surface of the support portion 3322 can be 2 to 5 times the area of ​​the horizontal cross-sectional area of ​​the collecting protrusion 3321. Since the continuous surface formed by the upper surface of the stop portion 3314 and the upper surface of the support portion 3322 is larger than the cross-sectional area of ​​the collecting protrusion 3321, the component can be stably supported. The area of ​​the continuous surface formed by the upper surface of the stop portion 3314 and the upper surface of the support portion 3322 can be 3% to 6% of the upper surface of the collecting unit 3310.

[0287] The support portion 3322 can support the current collecting protrusion 3321 such that when the pole unit 3320 is connected to the current collecting unit 3310, the current collecting protrusion 3321 is perpendicular to the current collecting unit 3310. The current collecting protrusion 3321 and the support portion 3322 can be integrally formed.

[0288] After the support portion 3322 is fitted into the opening 3315 of the current collector unit 3310, the support portion 3322 and the current collector unit 3310 can be joined by welding. Welding can be performed on the lower surface of the support portion 3322. Due to welding, a welded area can be formed on the lower surface of the support portion 3322.

[0289] like Figure 25 As illustrated in the figure, in this embodiment, the welding area may be formed on the outer periphery (welding area A) of the lower surface of the support portion 3322. Welding may be performed at the boundary surface between the support portion 3322 and the connecting portion 3313.

[0290] When the support portion 3322 is formed into a square plate shape, undesirable rotation of the current collection protrusion 3321 can be prevented by fitting the support portion 3322 into the opening 3315 of the current collection unit 3310.

[0291] The width of current collector 3300 can be 0.3 to 0.8 times the thickness of electrode assembly 1200. Current collector 3300 can have a thickness of 0.5 mm to 3.0 mm.

[0292] An insulator may be provided below the current collector 3300. The insulator may be an insulating plate or an insulating film. The insulator can more reliably protect the electrode contacts 1220 and 1230 as well as the electrode portion 1210.

[0293] After the pole unit 3320 is soldered to the current collector unit 3310, an insulator can be applied or attached to the lower surface of the current collector 3300 with a predetermined thickness.

[0294] In the following description, the current collector of the secondary battery according to the fourth embodiment of this disclosure will be described. Descriptions of elements that are the same as those in the first to third embodiments are omitted or simplified.

[0295] Figure 26 This is a view illustrating the current collector in a secondary battery according to a fourth embodiment of the present disclosure. Figure 27 This is a view illustrating the current collector unit in a secondary battery according to the fourth embodiment of the present disclosure. Figure 28A and Figure 28B This is a view illustrating the electrode cells in a secondary battery according to a fourth embodiment of the present disclosure. Figure 29 This is a view illustrating the process of assembling the current collector and the pole unit together according to the fourth embodiment of the present disclosure.

[0296] Figure 30 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a fourth embodiment of the present disclosure.

[0297] like Figure 26 As illustrated, the current collector 4300 may include a current collector unit 4310 and an electrode unit 4320. The current collector unit 4310 may be connected to multiple electrode contacts 1220 and 1230. The electrode unit 4320 may be connected to corresponding electrode terminals.

[0298] The current collector 4310 may have a rectangular shape extending along the longitudinal direction (y-direction) of the electrode assembly 1200, and may include a connecting portion 4313, a first current collector 4311, and a second current collector 4312 continuously arranged along the longitudinal direction of the rectangular shape. The connecting portion 4313, the first current collector 4311, and the second current collector 4312 may be made of the same material and may be integrally formed.

[0299] The first current collector 4311 can be soldered to a plurality of first electrode contacts 1220. The second current collector 4312 can be soldered to a plurality of second electrode contacts 1230. The connecting portion 4313 can be formed to have the same thickness as the first current collector 4311 and the second current collector 4312. The thickness of the connecting portion 4313 can be in the range of 0.5 mm to 3.0 mm. The radius of curvature of the edge of the upper surface of the current collector 4300 can be from 0.25 mm to 0.35 mm.

[0300] The connection part 4313 can be connected to the pole unit 4320.

[0301] like Figure 27 As shown in the diagram, an opening 4315 may be formed in the connecting portion 4313. The pole unit 4320 can be connected to the connecting portion 4313 through the opening 4315.

[0302] A recessed region 4317 may be formed in the lower surface of the current collector unit 4310. The recessed region 4317 may have a disc-shaped, square plate-shaped, or rectangular plate-shaped shape, and may define an empty space extending upward from the lower surface of the connecting portion 4313 of the current collector unit 4310. The cross-sectional area of ​​the recessed region 4317 may be larger than the cross-sectional area of ​​the opening 4315. For example, when the opening 4315 and the recessed region 4317 are disc-shaped, the diameter of the recessed region 4317 may be larger than the diameter of the opening 4315. The depth d1 of the recessed region 4317 may be 5% to 15% of the height h1 of the end of the current collector unit 4310.

[0303] The electrode unit 4320 can be connected to the current collector unit 4310, and the electrode contacts 1220 and 1230 of the electrode portion 1210 can be electrically connected to the corresponding electrode terminals. The material of the electrode unit 4320 can be the same as or different from the material of the current collector unit 4310.

[0304] like Figure 28AAs illustrated, the electrode unit 4320 may include a current collector protrusion 4321, a support portion 4322, and a flange 4323. The current collector protrusion 4321 may have a cylindrical shape with a predetermined height hc. The current collector protrusion 4321 may be electrically connected to a corresponding electrode terminal. When the current collector 4300 is used as a negative current collector, the upper end of the current collector protrusion 4321, which is made of copper, may be electroplated with nickel to form a nickel plating layer 4326, such as... Figure 28B As shown.

[0305] The support portion 4322 and the flange 4323 can be connected to the lower end of the current collecting protrusion 4321, and each can have a disc-shaped or rectangular plate-shaped form. The shape of the support portion 4322 can be the same as the shape of the opening 4315 of the current collecting unit 4310. The support portion 4322 can be inserted into the opening 4315 of the current collecting unit 4310. The support portion 4322 can support the current collecting protrusion 4321 such that when the pole unit 4320 is connected to the current collecting unit 4310, the current collecting protrusion 4321 is perpendicular to the current collecting unit 4310.

[0306] The diameter of the support portion 4322 can be smaller than the diameter of the recessed region 4317. Furthermore, the height h3 of the support portion 4322 can be the same as the length of the opening 4315. That is, when the support portion 4322 is inserted into the opening 4315, the lower surface of the support portion 4322 can be flush with the upper surface of the recessed region 4317, and can be positioned above the lower surface of the current collector unit 4310, i.e., inside the recessed region 4317. Figure 29 ).

[0307] A flange 4323 may be disposed between the collecting protrusion 4321 and the support portion 4322. The cross-sectional area of ​​the flange 4323 may be larger than the cross-sectional area of ​​the support portion 4322. Therefore, the flange 4323 may contact the upper surface of the connecting portion 4313 and may prevent the support portion 4322 from moving downward through the opening 4315 beyond a predetermined depth. When the support portion 4322 is inserted into the opening 4315, the flange 4323 may contact the peripheral surface of the connecting portion 4313 surrounding the opening 4315, thereby allowing the collecting protrusion 4321 to be supported more stably. The cross-sectional area of ​​the flange 4323 may be 5-15 times, preferably 10 times, the cross-sectional area of ​​the collecting protrusion 4321. When the flange 4323 is formed as a cylinder, the diameter of the collecting protrusion 4321 may be 20% to 50%, preferably 30%, of the diameter of the flange 4323.

[0308] When the current collector 4300 is connected to another component, the flange 4323 can define the lower limit position of the component to be connected to the current collector 4300. The flange 4323 can protrude a predetermined height from the upper surface of the connection portion 4313. Due to the flange 4323, the components assembled to the current collector 4300 can be horizontally aligned.

[0309] The height h2 of flange 4323 can be 1% to 5% of the thickness of electrode assembly 1200, and for example, 2.5%. The height h2 of flange 4323 can be calculated by the following formula: h2 = A × 0.005 × B / C, where A is the thickness of electrode assembly 1200, B is the length of electrode tab, and C is the number of groups of electrode tabs to be soldered to the current collector. In the two current collectors 4300 disposed on electrode portion 1210, flange 4323 can have the same height.

[0310] The flange 4323 may have a square plate shape, a rectangular plate shape, or a disc shape. The upper surface of the flange 4323 may be formed as a flat surface to support the component to be assembled thereon, and may have a predetermined area. The cross-sectional area of ​​the flange 4323 may be 3% to 6% of the upper surface of the current collector 4310.

[0311] When both the support portion 4322 and the flange 4323 have a cylindrical shape, the diameter of the flange 4323 can be 1.2 to 1.4 times the diameter of the support portion 4322. When both the support portion 4322 and the flange 4323 have a quadrilateral prism shape, the length of one side of the flange 4323 can be 1.2 to 1.4 times the length of one side of the support portion 4322. Because the length and area of ​​the flange 4323 are ensured, the pole unit 4320 can be stably fixed to the connecting portion 4313, and the component connected to the current collector protrusion 4321 can be stably supported.

[0312] The area of ​​the horizontal cross-section of the flange 4323 can be 2 to 5 times the area of ​​the horizontal cross-section of the collecting protrusion 4321. Furthermore, when the flange 4323 has a cylindrical shape, the diameter of the collecting protrusion 4321 can be 50% to 60% of the diameter of the flange 4323. Because the cross-sectional area of ​​the flange 4323 is larger than the cross-sectional area of ​​the collecting protrusion 4321 and the diameter of the flange 4323 is larger than the diameter of the collecting protrusion 4321, the components connected to it can be stably supported.

[0313] The flange 4323 can protrude upward from the upper surface of the connecting portion 4313, and the height h2 of the flange 4323 can be equal to or greater than the thickness of the current collecting unit 4310. Specifically, the height of the flange 4323 can be 100% to 120% of the height of the end of the current collecting unit 4310, i.e., the end of the first current collecting portion 4311 or the second current collecting portion 4312. When the height of the flange 4323 exceeds 120% of the thickness of the connecting portion 4313, the distance between the component connected to the current collecting protrusion 4321 and the connecting portion 4313 may increase, posing a risk of reduced airtightness.

[0314] Since the flange 4323 forms a stop, a stepped structure can be formed for the collector 4300.

[0315] To ensure that the component mounted on the manifold protrusion 4321 is stably supported on the flange 4323, the flange 4323 may have a predetermined area. The area of ​​the horizontal cross-section of the flange 4323 may be 2 to 5 times the area of ​​the horizontal cross-section of the manifold protrusion 4321. Because the cross-sectional area of ​​the flange 4323 is formed to be larger than the cross-sectional area of ​​the manifold protrusion 4321, the component can be stably supported.

[0316] To facilitate the connection between the current collecting protrusion 4321 and the component, the height hc of the current collecting protrusion 4321 can be formed to be greater than the height h2 of the flange 4323 within a predetermined range. Specifically, the height h2 of the flange 4323 can be 30% to 50% of the height hc of the current collecting protrusion 4321, and preferably 40%. When the height of the flange 4323 is greater than 50% of the height hc of the current collecting protrusion 4321, the height difference between the upper surface of the flange 4323 and the upper surface of the first current collecting portion 4311 and the upper surface of the second current collecting portion 4312 may increase, making it difficult to stably support the component.

[0317] The flow collection protrusion 4321, the support portion 4322, and the flange 4323 can be formed integrally.

[0318] When the current collector 4300 is used as a negative current collector, the upper end of the current collector protrusion 4321, made of copper, can be plated with nickel. The height of the nickel plating can be 1.5 mm to 2.5 mm from the upper end of the current collector protrusion 4321. The height of the nickel plating can be 30% to 50% of the height of the current collector protrusion 4321. The thickness of the nickel plating can be in the range of 2 μm to 4 μm. Because the upper end of the current collector protrusion 4321 is plated with nickel, the weld strength when the current collector protrusion 4321 is soldered to the electrode terminal can be further improved.

[0319] After the support portion 4322 is fitted into the opening 4315 of the current collector unit 4310, the support portion 4322 and the current collector unit 4310 can be joined by welding. Welding can be performed on the periphery of the lower surface of the support portion 4322. Due to welding, a weld area A can be formed on the lower surface of the support portion 4322.

[0320] like Figure 30 As illustrated in the figure, in this embodiment, the welding area can be formed on the outer periphery (welding area A) of the lower surface of the support portion 4322. The support portion 4322 can be positioned at a predetermined distance from the lower end of the connecting portion 4313. The lower surface of the support portion 4322 is flush with the upper surface of the recessed area 4317, which facilitates welding at the outer periphery of the lower surface of the support portion 4322. Even if welding burrs are generated, the welding burrs will be located within the recessed area 4317 and will not protrude below the lower surface of the current collector 4310.

[0321] According to this disclosure, a sufficient welding area can be ensured by using a support portion 4322 having a disc-shaped or rectangular shape, so that the current collection protrusion 4321 can be stably connected to the current collection unit 4310. Furthermore, when the support portion 4322 is formed into a square plate shape and received in the opening 4315, undesirable rotation of the current collection protrusion 4321 can be prevented.

[0322] The width of current collector 4300 can be 0.3 to 0.8 times the thickness of electrode assembly 1200. Current collector 4300 can have a thickness of 0.5 mm to 3.0 mm.

[0323] An insulator may be provided below the current collector 4300. The insulator may be an insulating plate or an insulating film. The insulator can more reliably protect the electrode contacts 1220 and 1230 as well as the electrode portion 1210.

[0324] After the pole unit 4320 is soldered to the current collector unit 4310, an insulator can be applied or attached to the lower surface of the current collector 4300 with a predetermined thickness.

[0325] In the following description, the current collector of the secondary battery according to the fifth embodiment of this disclosure will be described. Descriptions of elements that are the same as those in the first to fourth embodiments are omitted or simplified.

[0326] Figure 31 This is a view illustrating a current collector in a secondary battery according to a fifth embodiment of the present disclosure. Figure 32 This is a view illustrating the current collector unit in a secondary battery according to a fifth embodiment of the present disclosure. Figure 33A and Figure 33BThis is a view illustrating the electrode cells in a secondary battery according to a fifth embodiment of the present disclosure. Figure 34 This is a view illustrating the process of assembling a current collector unit and a polar unit together according to a fifth embodiment of the present disclosure.

[0327] Figure 35 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a fifth embodiment of the present disclosure.

[0328] like Figure 31 As illustrated, the current collector 5300 may include a current collector unit 5310 and a current collector unit 5320. The current collector unit 5310 may include a first current collector section 5311, a second current collector section 5312, and a connection section 5313.

[0329] The current collector 5310 may have a rectangular shape extending along the longitudinal direction (y-direction) of the electrode assembly 1200. The current collector 5310 may be configured such that the connecting portion 5313, the first current collector portion 5311, and the second current collector portion 5312 are continuously arranged along the longitudinal direction of the rectangular shape. The first current collector portion 5311 and the second current collector portion 5312 may have a predetermined height h1. Specifically, the height h1 of each of the first current collector portion 5311 and the second current collector portion 5312 may be in the range of 0.5 mm to 3.0 mm.

[0330] The connecting portion 5313 can be connected to one side of the first collector portion 5311. The second collector portion 5312 can be connected to the remaining sides of the first collector portion 5311. The connecting portion 5313 can be formed with a sitting region 5317. The sitting region 5317 can be formed by recessing a portion of the connecting portion 5313 into a predetermined depth d3. The depth d3 of the sitting region 5317 can be 30% to 50% of the height h1 of the end of the collector unit 5310. The cross-sectional shape of the sitting region 5317 can be square, rectangular, or circular.

[0331] The electrode unit 5320 can be electrically connected to a corresponding electrode terminal. The material of the electrode unit 5320 can be the same as or different from that of the current collector unit 5310. For example, both the current collector unit 5310 and the electrode unit 5320 can be made of aluminum. Alternatively, the current collector unit 5310 can be made of copper, and the electrode unit 5320 can be made of aluminum. According to this disclosure, since the current collector unit 5310 and the electrode unit 5320 are formed as separate components, flexibility in selecting the materials and dimensions of the components can be increased.

[0332] The pole unit 5320 may include a current collector protrusion 5321 and a support portion 5322 (see [reference]). Figure 33AThe current collector protrusion 5321 can have a cylindrical shape with a predetermined height hc. The current collector protrusion 5321 can be electrically connected to the corresponding electrode terminal. When the current collector 5300 is used as a negative current collector, the upper end of the current collector protrusion 5321, made of copper, can be electroplated with nickel to form a nickel plating layer 5326, such as... Figure 33B As shown.

[0333] The support portion 5322 can be connected to the lower end of the current collecting protrusion 5321, and can have a square plate shape, a rectangular plate shape, or a disc shape. The lower portion of the support portion 5322 can be received in the seating area 5317 of the connecting portion 5313. The height h3 of the support portion 5322 can be greater than the depth d3 of the seating area 5317. Therefore, when the support portion 5322 is seated in the seating area 5317, the upper surface of the support portion 5322 can protrude from the upper surface of the connecting portion 5313 by a predetermined height h2, and the lower surface of the support portion 5322 is lower than the upper surface of the current collecting unit 5310, so that the pole unit 5320 is stably supported on the current collecting unit 5310. The cross-sectional area of ​​the support portion 5322 is in the range of 150% to 300% of the cross-sectional area of ​​the current collecting protrusion 5321.

[0334] The height h2 of the support portion 5322 protruding from the upper surface of the connecting portion 5313, i.e., from the upper surface of the current collecting unit 5310, can be less than the thickness of the end of the current collecting unit 5310. Specifically, the height h2 of the support portion 5322 protruding from the upper surface of the connecting portion 5313 can be 30% to 50% of the height h1 of the end of the first current collecting portion 5311 or the second current collecting portion 5312. Due to the protrusion of the support portion 5322, a stepped structure of the current collector 5300 can be formed (see...). Figure 34 ).

[0335] The height h2 of the protruding portion can be equal to or greater than the height of the plurality of first electrode tabs 1220 and the plurality of second electrode tabs 1230 welded to the upper surface of the current collector 5300. The height h2 of the support portion 5322 protruding from the upper surface of the connecting portion 5313 can be calculated by the following formula: h2 = A × 0.005 × B / C, where A is the thickness of the electrode assembly 1200, B is the length of the electrode tabs, and C is the number of groups of electrode tabs to be welded to the current collector. As the number of first electrode tabs 1220 and second electrode tabs 1230 increases, that is, as the thickness of the electrode assembly 1200 (in Figure 2As the thickness (in the x-direction) of the support portion 5322 increases, the height h2 of the protruding portion can increase. The height h2 of the protruding portion of the support portion 5322 can be 1% to 5% of the thickness of the electrode assembly 1200, and for example, 2.5%. In the two current collectors 5300 disposed on the electrode portion 1210, the protruding portions of the support portion 5322 can have the same height h2. In order to stably support the component mounted on the current collector protrusion 5321 on the protruding portion of the support portion 5322, the support portion 5322 can have a predetermined area. The area of ​​the horizontal cross-section of the support portion 5322 can be 3 to 5 times the area of ​​the horizontal cross-section of the current collector protrusion 5321.

[0336] The support portion 5322 can be square plate-shaped, rectangular plate-shaped, or disc-shaped. In this embodiment, the case where the support portion 5322 has a square plate-shaped form will be described. The support portion 5322 and the seating area 5317 can have the same cross-sectional shape and therefore can be matched with each other.

[0337] The upper surface of the support portion 5322 can be formed as a flat surface to support the component to be assembled thereon. The manifold protrusion 5321 and the support portion 5322 can be formed integrally.

[0338] After the support portion 5322 is fitted into the mounting region 5317 of the current collector unit 5310, the support portion 5322 and the current collector unit 5310 can be joined by welding. Welding can be performed on the lower surface of the connecting portion 5313 where the mounting region 5317 is formed. By welding, a welding area can be formed on the lower surface of the connecting portion 5313.

[0339] like Figure 35 As illustrated in the figure, in this embodiment, the welding area can be formed on the lower surface of the connecting portion 5313 in a region (welding area C) corresponding to the lower surface of the support portion 5322. Welding can be performed on the lower surface of the connecting portion 5313, thereby welding the lower surface of the support portion 5322.

[0340] When the support portion 5322 is formed into a square plate shape, undesirable rotation of the current collection protrusion 5321 can be prevented by fitting the support portion 5322 into the square seating area 5317 of the current collection unit 5310.

[0341] The width of current collector 5300 can be 0.3 to 0.8 times the thickness of electrode assembly 1200. Current collector 5300 can have a thickness of 0.5 mm to 3.0 mm. The radius of curvature of the edge of the upper surface of current collector 5300 can be in the range of 0.25 mm to 0.35 mm.

[0342] An insulator may be provided below the current collector 5300. The insulator may be an insulating plate or an insulating film. The insulator can more reliably protect the electrode contacts 1220 and 1230 as well as the electrode portion 1210.

[0343] After the pole unit 5320 is soldered to the current collector unit 5310, an insulator can be applied or attached to the lower surface of the current collector 5300 with a predetermined thickness.

[0344] In the following description, the current collector of the secondary battery according to the sixth embodiment of this disclosure will be described. Descriptions of elements that are the same as those in the first to fifth embodiments are omitted or simplified.

[0345] Figure 36 This is a view illustrating a current collector in a secondary battery according to a sixth embodiment of the present disclosure. Figure 37 This is a view illustrating a current collector in a secondary battery according to a sixth embodiment of the present disclosure. Figure 38 This is a view illustrating the process of assembling a current collector unit and a polar unit together according to a sixth embodiment of the present disclosure.

[0346] Figure 39 This is a view illustrating the welding area on the lower surface of the current collector in a secondary battery according to a sixth embodiment of the present disclosure. Figure 40 This is a view illustrating a welding area on the lower surface of a current collector in a secondary battery according to another example of a sixth embodiment of the present disclosure.

[0347] like Figures 36 to 38 As illustrated, the current collector 6300 may include a current collector unit 6310 and a current collector unit 6320. The current collector unit 6310 may include a first current collector section 6311, a second current collector section 6312, and a connection section 6313.

[0348] The current collector 6310 may have a rectangular shape extending along the longitudinal direction (y-direction) of the electrode assembly 1200. The current collector 6310 may be configured such that the connecting portion 6313, the first current collector 6311, and the second current collector 6312 are continuously arranged along the longitudinal direction of the rectangular shape. The first current collector 6311, the second current collector 6312, and the connecting portion 6313 may each have predetermined thicknesses t1 and t2. The thickness t2 of the connecting portion 6313 may be the same as the thickness t1 of the first current collector 6311 and the second current collector 6312. Specifically, the thicknesses of the first current collector 6311, the second current collector 6312, and the connecting portion 6313 may be in the range of 0.5 mm to 3.0 mm.

[0349] The connecting portion 6313 can be connected to one side of the first collector portion 6311. The second collector portion 6312 can be connected to the remaining sides of the first collector portion 6311. The connecting portion 6313 can protrude from both the first collector portion 6311 and the second collector portion 6312. The upper surface of the connecting portion 6313 can be positioned to be a predetermined height h2 higher than the upper surfaces of the first collector portion 6311 and the second collector portion 6312.

[0350] The protruding height h2 of the connecting portion 6313 can be less than the height t1 of the end of the current collecting unit 6310. Specifically, the protruding height h2 of the connecting portion 6313 can be 30% to 50% of the height h1 of the end of the first current collecting portion 6311 or the second current collecting portion 6312. Because the connecting portion 6313 has a protruding structure, a stepped structure of the current collecting unit 6310 can be formed (see...). Figure 37 ).

[0351] The protruding height h2 of the connecting portion 6313 can be equal to or greater than the height of the plurality of first electrode contacts 1220 and the plurality of second electrode contacts 1230 welded to the upper surface of the current collector 6300. The protruding height h2 of the connecting portion 6313 can be calculated by the following formula: h2 = A × 0.005 × B / C, where A is the thickness of the electrode assembly 1200, B is the length of the electrode contacts, and C is the number of groups of electrode contacts to be welded to the current collector. As the number of first electrode contacts 1220 and second electrode contacts 1230 increases, that is, as the electrode assembly 1200 (in Figure 2 As the thickness increases in the x-direction, the protrusion height h2 of the connecting portion 6313 may increase. The protrusion height h2 of the connecting portion 6313 may be 1% to 5% of the thickness of the electrode assembly 1200, and for example, it may be 2.5% of the thickness of the electrode assembly 1200. In the two current collectors 6300 disposed on the electrode portion 1210, the connecting portion 6313 may protrude at the same height.

[0352] The upper surface of the connecting portion 6313 can be formed as a flat surface to support the component to be assembled thereto. A seating area can be formed on the upper surface of the connecting portion 6313. The upper surface of the seating area can be flush with the upper surface of the connecting portion 6313. The pole unit 6320 can be connected to the surface of the seating area.

[0353] The connecting portion 6313 can be formed by bending the current collecting unit 6310 so that one end of the current collecting unit 6310 protrudes. When the current collecting unit 6310 is bent, the surface of the connection between the connecting portion 6313 and the first current collecting portion 6311 can be inclined.

[0354] The electrode unit 6320 can be electrically connected to a corresponding electrode terminal. The material of the electrode unit 6320 can be the same as or different from that of the current collector unit 6310. For example, both the current collector unit 6310 and the electrode unit 6320 can be made of aluminum. Alternatively, the current collector unit 6310 can be made of copper, and the electrode unit 6320 can be made of aluminum. According to this disclosure, since the current collector unit 6310 and the electrode unit 6320 are formed as separate components, flexibility in selecting the materials and dimensions of the components can be increased.

[0355] The electrode unit 6320 may include a current collector protrusion 6321. The current collector protrusion 6321 may have a cylindrical shape with a predetermined height hc. The current collector protrusion 6321 may be electrically connected to a corresponding electrode terminal. The current collector protrusion 6321 may be connected to a seating area formed on the upper surface of the connection portion 6313.

[0356] The current collecting protrusion 6321 and the current collecting unit 6310 can be connected to each other by welding. Welding can be performed on the lower surface of the connecting portion 6313. Through welding, a welded area can be formed on the lower surface of the connecting portion 6313. Figure 39 As shown, in one embodiment, the welding area may be formed in a region (welding area D) corresponding to the outer periphery of the manifold protrusion 6321. In another embodiment, the welding area may be formed in the entire region (welding area E, see [reference]) corresponding to the bottom surface of the manifold protrusion 6321. Figure 40 In this case, the laser output used for welding in the first welding area E1 corresponding to the outer periphery of the current collecting protrusion 6321 can be greater than the laser output in the second welding area E2 corresponding to the inner side of the current collecting protrusion 6321.

[0357] To facilitate the connection between the current collecting protrusion 6321 and the component, the height hc of the current collecting protrusion 6321 can be formed within a predetermined range to be greater than the protrusion height h2 of the connecting portion 6313. Specifically, the protrusion height h2 of the connecting portion 6313 can be 10% to 20% of the height hc of the current collecting protrusion 6321, and for example, it can be 15% of the height hc of the current collecting protrusion 6321.

[0358] The width of current collector 6300 can be 0.3 to 0.8 times the thickness of electrode assembly 1200. The thickness of current collector 6300 can be 0.5 mm to 3.0 mm. The radius of curvature of the edge of the upper surface of current collector 6300 can be in the range of 0.25 mm to 0.35 mm.

[0359] An insulator may be provided below the current collector 6300. The insulator may be an insulating plate or an insulating film. The insulator can more reliably protect the electrode contacts 1220 and 1230 as well as the electrode portion 1210.

[0360] After the pole unit 6320 is soldered to the current collector unit 6310, an insulator can be applied or attached to the lower surface of the current collector 6300 to a predetermined thickness.

[0361] The connection structure between the connection portion and the pole unit disclosed herein can be applied to various types of collectors.

[0362] The current collector of the secondary battery according to the seventh embodiment of this disclosure will now be described. Figure 41 This is a cross-sectional view of the current collector 7300 in a secondary battery according to the seventh embodiment of this disclosure. Figure 42 This is a cross-sectional view of the current collector unit in a secondary battery according to the seventh embodiment of this disclosure. Figure 43 and Figure 44 This is a cross-section of an electrode unit in a secondary battery according to the seventh embodiment of this disclosure. Figure 45 This is a view illustrating the process of assembling the current collector and the pole unit in the seventh embodiment of this disclosure. Figure 46 yes Figure 45 A magnified view of a portion of the image.

[0363] The current collector 7300 includes a current collector unit 7310 and an electrode unit 7320. The current collector unit 7310 can be connected to multiple electrode tabs. The electrode unit 7320 can be connected to corresponding electrode terminals. The current collector unit 7310 may have a rectangular shape extending along the longitudinal direction (y-direction) of the electrode assembly. The current collector unit 7310 may include a connecting portion 7313, a first current collector portion 7311, and a second current collector portion 7312 continuously arranged along the longitudinal direction of the rectangular shape. The connecting portion 7313, the first current collector portion 7311, and the second current collector portion 7312 may be made of the same material and may be integrally formed. Multiple first electrode tabs 1220 may be bent and welded to the upper surface of the first current collector portion 7311. Multiple second electrode tabs 1230 may be bent and welded to the upper surface of the second current collector portion 7312. The first current collector portion 7311 and the second current collector portion 7312 may have a predetermined thickness h1. The connecting portion 7313 may be formed to have the same thickness as the first current collecting portion 7311 and the second current collecting portion 7312. Specifically, the thickness of each of the first current collecting portion 7311, the second current collecting portion 7312, and the connecting portion 7313 may be in the range of 0.5 mm to 3.0 mm. The connecting portion 7313 and the second current collecting portion 7312 are located on opposite sides of the first current collecting portion 7311, respectively.

[0364] An opening 7315 and a recessed region 7317 are formed in the connecting portion 7313, such as Figure 42 As shown. The recessed region 7317 is recessed upward from the lower surface of the current collector unit 7310, and can be formed into a circular, rectangular, or square shape. The cross-sectional area of ​​the recessed region 7317 can be larger than the cross-sectional area of ​​the opening 7315, and the lower edge of the opening 7315 is located within the recessed region 7317. The depth d1 of the recessed region 7317 can be 5% to 15% of the thickness h1 of the current collector unit 7310.

[0365] The electrode unit 7320 is connected to the current collector unit 7310 via the opening 7315 of the connection portion 7313. The electrode unit 7320 includes a current collector protrusion 7321, a support portion 7322, a flange 7323, and a protruding end 7324. The current collector protrusion 7321 may be cylindrical and have a predetermined height hc. The current collector protrusion 7321 can be electrically connected to a corresponding electrode terminal. When the current collector 7300 is used as a negative current collector, the upper end of the current collector protrusion 7321 may be plated with nickel to form a nickel plating layer 7326, such as... Figure 44 As shown. Since a nickel plating layer 7326 is formed on the upper end of the current collector protrusion 7321, the welding strength when the current collector protrusion 7321 is welded to the electrode terminal can be further improved.

[0366] The support portion 7322 is configured to connect to the current collector unit 7310. Specifically, the shape of the support portion 7322 corresponds to the shape of the opening 7315 of the connecting portion 7313 of the current collector unit 7310, and the support portion 7322 can be inserted into the opening 7315. Preferably, the thickness h3 of the support portion 7322 can be equal to or slightly less than the depth of the opening 7315, such that when the support portion 7322 is inserted into the opening 7315, the lower surface of the support portion 7322 is substantially flush with the upper surface of the recessed region 7317, and is located within the recessed region 7317, thereby facilitating the welding of the current collector unit 7310 and the pole unit 7320 in the recessed region 7317.

[0367] Flange 7323 is located between the current collecting protrusion 7321 and the support portion 7322, and the cross-sectional area of ​​flange 7323 can be larger than that of support portion 7322. This allows the lower surface of flange 7323 to contact the upper surface of connecting portion 7313 of current collecting unit 7310 when support portion 7322 is inserted into opening 7315, preventing support portion 7322 from penetrating deeper than a predetermined depth through opening 7315 and providing more stable support for current collecting protrusion 7321. The cross-sectional area of ​​flange 7323 can be 5-15 times, preferably 10 times, the cross-sectional area of ​​current collecting protrusion 7321. When flange 7323 is formed as a cylinder, the diameter of current collecting protrusion 7321 can be 20% to 50%, preferably 30%, of the diameter of flange 7323. Flange 7323 can protrude from the upper surface of current collecting unit 7310 to form a stop portion, creating a stepped structure in current collector 7300. The upper surface of flange 7323 is formed as a flat surface to support components to be assembled thereon. The thickness (height) h2 of flange 7323 can be calculated using the following formula: h2 = A × 0.005 × B / C, where A is the thickness of electrode assembly 1200, B is the length of electrode tabs, and C is the number of groups of electrode tabs to be welded to the current collector. As the number of groups of electrode tabs welded to the current collector increases, the thickness h2 of flange 7323 can decrease. The thickness (height) h2 of flange 7323 can be equal to or greater than the height of the plurality of first electrode tabs 1220 and the plurality of second electrode tabs 1230 welded to the upper surface of current collector unit 7310 of current collector 7300. The thickness h2 of flange 7323 can be equal to or greater than the thickness h1 of current collector unit 7310. In one example, the thickness h2 of flange 7323 can be 100% to 120% of the thickness h1 of current collector unit 7310. The thickness h2 of the flange 7323 can be 30% to 50% of the height hc of the current collecting protrusion 7321, and preferably 40%.

[0368] The protruding end 7324 protrudes downward from the lower surface of the support portion 7322. The cross-sectional area of ​​the protruding end 7324 is smaller than the cross-sectional area of ​​the support portion 7322, thereby forming a recessed space 7327 between the support portion 7322 and the protruding end 7324, such as... Figure 46As shown. When the support portion 7322 is inserted into the opening 7315 of the connecting portion 7313 of the current collector unit 7310 and connected to the current collector unit 7310, an annular space of width W (i.e., a portion of the recessed region 7317 and the recessed space 7327) is formed between the outer periphery of the protruding end 7324 and the outer periphery of the recessed region 7317. Welding between the current collector unit 7310 and the pole unit 7320 can be performed from the lower side of the current collector unit 7310 within this annular space. Since the lower surface of the support portion 7322 is located within this annular space, even if welding burrs are generated during welding, the welding burrs will be located within this annular space and will not protrude downward from the lower surface of the current collector unit 7310. Preferably, the height h4 of the protruding end 7324 protruding from the lower surface of the support portion 7322 can be equal to the depth d1 of the recessed region 7317, such that when the support portion 7322 is inserted into the opening 7315 of the connection portion 7313 of the current collector unit 7310, the lower surface of the protruding end 7324 is substantially flush with the lower surface of the connection portion 7313, so that an insulator can be applied or attached to the lower surface of the current collector unit 7310 after the pole unit 7320 is welded to the current collector unit 7310.

[0369] Figure 47 The welding area between the current collector 7310 and the pole unit 7320 is shown. Welding can be performed between the outer periphery of the support 7322 and the outer periphery of the opening 7315 within the annular space between the outer periphery of the protruding end 7324 and the inner periphery of the recessed region 7317, forming welding area A. Figure 47 In the example shown, the periphery of the protruding end 7324 and the recessed area 7317 are concentric circles, and the difference between the diameter of the recessed area 7317 and the diameter of the protruding end 7324 is W, thereby forming an annular space with a width of W, and the welding area A is located in this annular space.

[0370] The current collector of the secondary battery according to the eighth embodiment of this disclosure will now be described. Figure 48 This is a cross-sectional view of the current collector 8300 in a secondary battery according to the eighth embodiment of this disclosure. Figure 49 This is a cross-sectional view of the current collector unit in a secondary battery according to the eighth embodiment of this disclosure. Figure 50 and Figure 51 This is a cross-section of an electrode unit in a secondary battery according to the eighth embodiment of this disclosure. Figure 52 This is a view illustrating the process of assembling the current collector and the pole unit in the eighth embodiment of this disclosure. Figure 53 The welding area on the lower surface of the current collector 8300 in the secondary battery according to the eighth embodiment of the present disclosure is shown.

[0371] The current collector 8300 includes a current collector unit 8310 and an electrode unit 8320. The current collector unit 8310 can be connected to multiple electrode tabs. The electrode unit 8320 can be connected to corresponding electrode terminals. The current collector unit 8310 may have a rectangular shape extending along the longitudinal direction (y-direction) of the electrode assembly. The current collector unit 8310 may include a connecting portion 8313, a first current collector portion 8311, and a second current collector portion 8312 continuously arranged along the longitudinal direction of the rectangular shape. The connecting portion 8313, the first current collector portion 8311, and the second current collector portion 8312 may be made of the same material and may be integrally formed. Multiple first electrode tabs 1220 may be bent and welded to the upper surface of the first current collector portion 8311. Multiple second electrode tabs 1230 may be bent and welded to the upper surface of the second current collector portion 8312. The first current collector portion 8311 and the second current collector portion 8312 may have a predetermined thickness h1. The connecting portion 8313 may be formed to have the same thickness as the first collector portion 8311 and the second collector portion 8312. Specifically, the thickness of each of the first collector portion 8311, the second collector portion 8312, and the connecting portion 8313 may be in the range of 0.5 mm to 3.0 mm. The connecting portion 8313 and the second collector portion 8312 are located on opposite sides of the first collector portion 8311, respectively. An opening 8315 is formed in the connecting portion 7315. The depth of the opening 8315 is equal to the thickness of the connecting portion 8313.

[0372] The electrode unit 8320 is connected to the current collector unit 8310 via the opening 8315 of the connection portion 8313 of the current collector unit 8310. The electrode unit 8320 includes a current collector protrusion 8321 and a support portion 8322. The current collector protrusion 8321 may be cylindrical. The current collector protrusion 8321 may be electrically connected to the corresponding electrode terminal. When the current collector 8300 is used as a negative current collector, the upper end of the current collector protrusion 8321 may be plated with nickel to form a nickel plating layer 8326, such as... Figure 51 As shown. Since a nickel plating layer 8326 is formed on the upper end of the current collector protrusion 8321, the welding strength when the current collector protrusion 8321 is welded to the electrode terminal can be further improved.

[0373] The support portion 8322 is configured to connect to the current collector unit 8310. Specifically, the shape of the support portion 8322 corresponds to the shape of the opening 8315 of the connecting portion 8313 of the current collector unit 8310, and the support portion 8322 can be inserted into the opening 8315. The thickness h3 of the support portion 8322 can be greater than the depth of the opening 8315, such that when the support portion 8322 is inserted into the opening 8315, the lower surface of the support portion 8322 is flush with the lower surface of the connecting portion 8313, while the upper surface of the support portion 8322 protrudes from the upper surface of the connecting portion 8313 of the current collector unit 8310, forming a stepped structure of the current collector 8300. The height h2 of the upper surface of the support portion 8322 protruding from the upper surface of the connecting portion 8313 can be calculated using the following formula: h2 = A × 0.005 × B / C, where A is the thickness of the electrode assembly 1200, B is the length of the electrode tab, and C is the number of groups of electrode tabs to be welded to the current collector. The height h2 of the upper surface of the support portion 8322 protruding from the upper surface of the connecting portion 8313 can be equal to or greater than the height of the plurality of first electrode tabs 1220 and the plurality of second electrode tabs 1230 welded to the upper surface of the current collector unit 8310 of the current collector 8300. The upper surface of the support portion 8322 is formed as a flat surface for supporting the components to be assembled thereon. The height h2 of the upper surface of the support portion 8322 protruding from the upper surface of the connecting portion 8313 can be less than the thickness h1 of the current collector unit 8310. In one example, the height h2 by which the upper surface of the support portion 8322 protrudes from the upper surface of the connecting portion 8313 can be 30% to 50% of the thickness h1 of the current collector unit 8310.

[0374] After the support portion 8322 is fitted into the opening 8315 of the current collector 8310, the support portion 8322 and the current collector 8310 can be joined by welding. Figure 53 The welding area between the support portion 8322 and the current collector 8310 is shown. Welding can be performed from the underside of the current collector 8300 between the outer periphery of the support portion 8322 and the inner periphery of the opening 8315, thereby forming a welding area A on the lower surface of the current collector 8300.

[0375] Figure 54 This is a view illustrating the current collector in a first modified secondary battery according to a first embodiment of the present disclosure. Figure 55 and Figure 56 This is a view illustrating the current collector in a second modified secondary battery according to the first embodiment of the present disclosure.

[0376] In a first modification of the first embodiment of the present disclosure, the current collector 1300A may include a current collector unit 1310 and a pole unit 1320. The current collector 1300A has a substantially the same structure as the current collector 1300 in the secondary battery according to the first embodiment of the present disclosure, the only difference being the position of the connection portion 1313A of the current collector unit 1310. Figure 54 The current collector 1310 shown may have a rectangular shape extending in the longitudinal direction (y-direction) of the electrode assembly 1200. The current collector 1310 may be configured such that the first current collector portion 1311, the connecting portion 1313A, and the second current collector portion 1312 are continuously arranged in the longitudinal direction of the rectangular shape. The first current collector portion 1311, the connecting portion 1313A, and the second current collector portion 1312 may all be formed of the same material and may be integrally formed. A stop portion 1314 protrudes from the upper surface of the connecting portion 1313A, forming a stepped structure of the current collector 1300A.

[0377] The first current collector 1311 can be soldered to a plurality of first electrode contacts 1220. The plurality of first electrode contacts 1220 can be bent onto and soldered to the first current collector 1311. The second current collector 1312 can be soldered to a plurality of second electrode contacts 1230. The plurality of second electrode contacts 1230 can be bent onto and soldered to the second current collector 1312. The first current collector 1311 and the second current collector 1312 can have a predetermined height. Specifically, the height of each of the first current collector 1311 and the second current collector 1312 can be in the range of 0.5 mm to 3.0 mm.

[0378] The connecting portion 1313A can be disposed between the first current collector portion 1311 and the second current collector portion 1312. The first current collector portion 1311 and the second current collector portion 1312 can be connected to one side and the remaining side of the connecting portion 1313A, respectively. Since the first current collector portion 1311 and the second current collector portion 1312 are spaced apart from each other by the connecting portion 1313A, the plurality of first electrode contacts 1220 and the plurality of second electrode contacts 1230 will not interfere with each other when they are respectively soldered to the first current collector portion 1311 and the second current collector portion 1312.

[0379] The current collector in the second modified secondary battery according to the first embodiment of the present disclosure has a similar structure to the current collector 1300 in the secondary battery according to the first embodiment of the present disclosure, the only difference being the design of the current collector unit, and more specifically, the only difference being the connection between the first current collector portion and the second current collector portion and the connecting portion of the current collector unit. Figure 55 and Figure 56The current collectors 1310B and 1310C shown may have a "U" shape formed by two rectangular structures connected to each other and extending in the longitudinal direction (y-direction) of the electrode assembly 1200. The first current collector portion 1311 may be connected to an end portion of one side of the rectangular connecting portion 1313 in the x-direction. Figures 55-56 The upper part of the middle), and the second collector part 1312 can be connected to another end part of the side of the connecting part 1313 along the x direction ( Figures 55-56 (The lower part of the middle). That is, the first collector portion 1311 and the second collector portion 1312 can be vertically connected to the connecting portion 1313, and the first collector portion 1311 and the second collector portion 1312 can be arranged parallel to each other and spaced apart from each other in the x direction. The stop portion 1314 protrudes from the upper surface of the connecting portion 1313, forming a stepped structure of the collectors 1300B and 1300C.

[0380] The first collector section 1311 and the second collector section 1312 can be spaced apart from each other by a predetermined distance in the x-direction. Figure 55 In the example shown, the first current collector 1311 and the second current collector 1312 may have the same length and width. However, this disclosure is not limited thereto, and the first current collector 1311 and the second current collector 1312 may have different widths depending on the arrangement of the electrode contacts and the thickness of the electrode portions (see [link to relevant documentation]). Figure 56 The connecting portion 1313, the first current collection portion 1311, and the second current collection portion 1312 can all be formed of the same material and can be integrally formed.

[0381] The first current collector 1311 can be soldered to a plurality of first electrode contacts 1220. The plurality of first electrode contacts 1220 can be bent onto and soldered to the first current collector 1311. The second current collector 1312 can be soldered to a plurality of second electrode contacts 1230. The plurality of second electrode contacts 1230 can be bent onto and soldered to the second current collector 1312. The first current collector 1311 and the second current collector 1312 can have a predetermined height. Specifically, the height of each of the first current collector 1311 and the second current collector 1312 can be in the range of 0.5 mm to 3.0 mm.

[0382] Figure 57 This is a flowchart illustrating a method for manufacturing a secondary battery according to a first embodiment of the present disclosure. Figure 58 This is a view illustrating a plurality of first electrode contacts 1220 and a plurality of second electrode contacts 1230 that are individually grouped in a secondary battery according to a first embodiment of the present disclosure. Figure 59This is a view illustrating a plurality of first electrode contacts 1220 and a plurality of second electrode contacts 1230 that are initially welded in a secondary battery according to a first embodiment of the present disclosure. Figure 60 The illustration shows a perspective view of the current collector 1300 to be installed onto the electrode assembly. Figure 61 This is a view illustrating a current collector 1300 disposed between a plurality of first electrode contacts 1220 and a plurality of second electrode contacts 1230 in a secondary battery according to a first embodiment of the present disclosure. Figure 62 and Figure 63 This is a view illustrating the first electrode tab 1220 and the second electrode tab 1230 welded to the current collector 1300 in a secondary battery according to a first embodiment of the present disclosure. Figure 64 This is a view illustrating the cover assembly 1400 connected to the electrode assembly 1200 in a secondary battery according to a first embodiment of the present disclosure.

[0383] like Figure 57 As shown, in order to manufacture a secondary battery according to the first embodiment of the present disclosure, an electrode assembly is prepared (step S5100). The electrode assembly 1200 includes an electrode portion 1210 and a plurality of first electrode tabs 1220 and a plurality of second electrode tabs 1230 formed at one end of the electrode portion.

[0384] A plurality of first electrode tabs 1220 and a plurality of second electrode tabs 1230 are disposed at one end of the electrode portion 1210. When the plurality of electrode elements forming the electrode portion are stacked, the plurality of first electrode tabs 1220 overlap each other at a first position, and the plurality of second electrode tabs 1230 overlap each other at a second position. That is, the plurality of first electrode tabs 1220 are grouped at the first position, and the plurality of second electrode tabs 1230 are grouped at the second position. The first position and the second position are spaced apart from each other on the electrode element, and the grouped plurality of first electrode tabs 1220 and the grouped plurality of second electrode tabs 1230 may be spaced apart from each other in the thickness direction (x direction) and longitudinal direction (y direction) of the electrode assembly 1200. Figure 58 As shown, a plurality of first electrode contacts 1220 grouped together can be disposed at one end of the electrode assembly 1200 in the thickness direction, while a plurality of second electrode contacts 1230 grouped together can be disposed at the remaining end of the electrode assembly 1200 in the thickness direction.

[0385] Next, a plurality of first electrode contacts 1220 are welded together, and a plurality of second electrode contacts 1230 are welded together (step S5200). The plurality of first electrode contacts 1220 and the plurality of second electrode contacts 1230 are aligned to be spaced apart from each other in the longitudinal direction of the electrode assembly 1200. The grouped and aligned plurality of electrode contacts are initially welded, such that the first electrode contacts 1220 are welded together and the second electrode contacts 1230 are welded together (see...). Figure 59 ).

[0386] The current collector 1300 is disposed between the plurality of first electrode contacts 1220 and the plurality of second electrode contacts 1230 that have been initially welded (step S5300), such as Figure 60 and Figure 61 As shown. In order to connect multiple electrode contacts 1220 and 1230 to the current collector 1300, in this embodiment, the electrode contacts 1220 and 1230 with the same polarity are divided into two groups and soldered to the same current collector 300.

[0387] At one end of the electrode portion 1210, a space is formed between a plurality of first electrode contacts 1220 and a plurality of second electrode contacts 1230 that have been initially welded. To facilitate placement of the current collector 1300, the welded first electrode contacts 1220 and the welded second electrode contacts 1230 can be bent outwards from the electrode assembly 1200. The current collector 1300 is placed between the first electrode contacts 1220 and the second electrode contacts 1230.

[0388] Both the first electrode tab 1220 and the second electrode tab 1230 are bent toward the upper surface of the current collector 1300 (step S5400). Multiple first electrode tabs 1220 are bent toward the upper surface of the first current collecting portion 1311 of the current collector 1300. Multiple second electrode tabs 1230 are bent toward the upper surface of the second current collecting portion 1312 of the current collector 1300. The multiple first electrode tabs 1220 and the multiple second electrode tabs 1230 are bent in opposite directions, such as... Figure 61 As shown.

[0389] The current collector 1300 is soldered to the first electrode contacts 1220 and the second electrode contacts 1230 placed on the current collector 1300 (step S5500). A plurality of first electrode contacts 1220 are soldered to the first current collector section 1311, and a plurality of second electrode contacts 1230 are soldered to the second current collector section 1312. Along the longitudinal direction (y-direction) of the current collector 1300, the first electrode contacts 1220 and the second electrode contacts 1230 are spaced apart from each other by a distance S, such as... Figure 62As shown. The spacing S can be 5% to 15% of the longitudinal length of the current collector 1300. If the spacing S is less than 5% of the longitudinal length of the current collector 1300, welding burrs generated during the second welding process (i.e., welding the electrode tabs to the current collector) may concentrate between the first electrode tab 1220 and the second electrode tab 1230, easily causing excessive and uneven weld thickness. If the distance S is greater than 15% of the longitudinal length of the current collector 1300, the second electrode tab 1230 will be close to the longitudinal end edge of the current collector 1300, which may affect the welding between the second electrode tab 1230 and the current collector 1300. Welding can be performed from above the multiple first electrode tabs 1220 and multiple second electrode tabs 1230. Welding can be performed using ultrasonic welding, laser welding, etc. In addition, the first electrode tabs 1220 and the second electrode tabs 1230 can be welded to the current collector 1300 in a generally aligned manner along the longitudinal direction (y direction) of the electrode assembly, as shown. Figure 63 As shown.

[0390] During welding, in the first current collecting section 1311 of the current collector 1300, welding can be performed from a plurality of first electrode contacts 1220 toward the first current collecting section 1311. In the second current collecting section 1312 of the current collector 1300, welding can be performed from a plurality of second electrode contacts 1230 toward the second current collecting section 1312.

[0391] In this embodiment, after the plurality of electrode contacts are initially welded such that the first electrode contacts 1220 are welded to each other and the second electrode contacts 1230 are welded to each other, the electrode contacts are welded to the current collector 1300. However, in other embodiments, the plurality of electrode contacts 1220 and 1230 may be bent onto the current collector 1300 and directly welded to the current collector 1300 without the need for initial welding.

[0392] Electrode assembly 1200 with current collector 1300 welded on (see Figure 62 and Figure 63 The housing 1100 is contained within the outer casing 1100. The cover assembly 1400 seals the opening of the outer casing 1100. (As shown...) Figure 64 As shown, after the current collector protrusion 1321 is inserted into the through hole of the electrode terminal 1420 of the cover assembly 1400, the outer peripheral surface of the end of the current collector protrusion 1321 can be welded to the inner peripheral surface of the end of the through hole of the electrode terminal 1420.

[0393] Figure 65 It shows along Figure 64 The cross-sectional view taken by line B-B' in the diagram. (See diagram below.) Figure 65As shown, when installed in place, the current collecting protrusion 1321 of the current collector 1300 passes through the through hole in the electrode terminal 1420 of the cover assembly 1400. The lower structure of the cover assembly 1400 can be supported by the stop portion 1314 of the current collector 1300. Thus, the cover assembly 1400 can maintain a stable distance from the upper surfaces of the first current collecting portion 1311 and the second current collecting portion 1312 of the current collecting unit 1310.

[0394] The above description uses a secondary battery according to the first embodiment of this disclosure as an example to illustrate a method for manufacturing a secondary battery, and shows the installation between the current collector 1300, the electrode assembly 1200, and the cover assembly 1400. Secondary batteries according to other embodiments of this disclosure can be manufactured similarly.

[0395] For example, Figure 66 The diagram illustrates the connection between the current collector 1300A of a first modified secondary battery according to a first embodiment of the present disclosure and the first electrode contact 1220 and the second electrode contact 1230 of the electrode assembly 1200. Figure 67 It shows along Figure 66 The longitudinal section taken along line S2-S2' shows the connection between current collector 1300A, electrode assembly 1200, and cover assembly 1400. (See diagram below.) Figure 66 and Figure 67 As shown, the first electrode contact 1220 and the second electrode contact 1230 are respectively welded to the first current collection portion 1311 and the second current collection portion 1312 of the current collection unit 1310 of the current collector 1300A on both sides of the current collection protrusion 1321.

[0396] For example, Figure 68 The connection between the current collector 1300B of the second modified secondary battery according to the first embodiment of the present disclosure and the first electrode contact 1220 and the second electrode contact 1230 of the electrode assembly 1200 is shown. Figure 69 It shows along Figure 68 The longitudinal section taken along line S3-S3' shows the connection between current collector 1300B, electrode assembly 1200, and cover assembly 1400.

[0397] For example, Figure 70 The connection between the current collector 1300C of a second modified secondary battery according to the first embodiment of this disclosure and the electrode contacts 1260, 1220, 1230 of the electrode assembly 1200 is shown. For example... Figure 70 As shown, electrode tab 1260 is welded to the first current collection portion 1311 of current collection portion 1310C of current collector 1300C, and electrode tabs 1220 and 1230 are welded to the second current collection portion 1312 of current collection portion 1310C of current collector 1300C.

[0398] When the current collector is welded to the upper portion of the electrode tabs, the current collector needs to be relatively thin to transfer heat to the electrode tabs located below the current collector, thus reducing durability. However, according to this disclosure, since multiple electrode tabs are bent onto and welded to the current collector, sufficient thickness of the current collector can be ensured, and the electrode tabs can be welded to the current collector more effectively.

[0399] Furthermore, in this disclosure, since multiple electrode contacts with the same polarity are divided into two groups and welded, the electrode contacts can be stably welded without any unwelded portions.

[0400] According to this disclosure, since the electrode contacts are positioned on the current collector 1300 and welded from above the electrode contacts, the current collector 1300 can have a relatively large thickness, and the risk of damaging the separators disposed in the electrode section can be reduced. Therefore, the durability of the secondary battery can also be improved.

[0401] The current collector of the secondary battery according to the ninth embodiment of this disclosure will now be described. Figure 71 This is a cross-sectional view of the current collector 9300 in a secondary battery according to the ninth embodiment of this disclosure. Figure 72 This is a cross-sectional view of the current collector unit in a secondary battery according to the ninth embodiment of this disclosure. Figure 73 and Figure 74 This is a cross-section of an electrode unit in a secondary battery according to the ninth embodiment of this disclosure. Figure 75 This is a view illustrating the process of assembling the current collector unit and the electrode unit in the ninth embodiment of this disclosure. The current collector 9300 of the secondary battery according to the ninth embodiment of this disclosure has a substantially the same structure as the current collector 7300 of the secondary battery according to the seventh embodiment of this disclosure, the only difference being the design of the current collector unit.

[0402] The current collector 9300 includes a current collector unit 9310 and an electrode unit 9320. The current collector unit 9310 can be connected to multiple electrode tabs. The current collector unit 9310 can have a rectangular shape extending along the longitudinal direction (y-direction) of the electrode assembly. The current collector unit 9310 may include a connecting portion 9313, a first current collector portion 9311, and a second current collector portion 9312 continuously arranged along the longitudinal direction of the rectangular shape. The connecting portion 9313, the first current collector portion 9311, and the second current collector portion 9312 can be made of the same material and can be integrally formed. Multiple first electrode tabs 1220 can be bent and welded to the upper surface of the first current collector portion 9311. Multiple second electrode tabs 1230 can be bent and welded to the upper surface of the second current collector portion 9312. The first current collector portion 9311 and the second current collector portion 9312 can have a predetermined thickness h1. The connecting portion 9313 may be formed to have the same thickness as the first current collecting portion 9311 and the second current collecting portion 9312. Specifically, the thickness of each of the first current collecting portion 9311, the second current collecting portion 9312, and the connecting portion 9313 may be in the range of 0.5 mm to 3.0 mm. The connecting portion 9313 and the second current collecting portion 9312 are located on opposite sides of the first current collecting portion 9311, respectively.

[0403] An opening 9315 and a recessed region 9317 are formed in the connecting portion 9313, such as Figure 72 As shown. The recessed region 9317 is recessed upward from the lower surface of the current collection unit 9310 and communicates with the opening 9315, and can be formed into a circular, rectangular, or square shape. The cross-sectional area of ​​the recessed region 9317 is smaller than the cross-sectional area of ​​the opening 9315, so that a step portion 9316 is formed between the opening 9315 and the recessed region 9317. The depth d1 of the recessed region 9317 can be 5% to 15% of the thickness h1 of the current collection unit 9310.

[0404] The electrode unit 9320 can be connected to the corresponding electrode terminal. The electrode unit 9320 is connected to the current collector unit 9310 via the opening 9315 of the connection portion 9313 of the current collector unit 9310. The electrode unit 9320 has the same structure as the electrode unit 7320 of the current collector 7300 of the secondary battery according to the seventh embodiment of this disclosure. Figure 73 As shown, the electrode unit 9320 includes a current collector protrusion 9321, a support portion 9322, a flange 9323, and a protruding end 9324. The current collector protrusion 9321 may be cylindrical and have a predetermined height hc. The current collector protrusion 9321 can be electrically connected to the corresponding electrode terminal. When the current collector 9300 is used as a negative current collector, the upper end of the current collector protrusion 9321 may be plated with nickel to form a nickel plating layer 9326, such as... Figure 74As shown. Since a nickel plating layer 9326 is formed on the upper end of the current collector protrusion 9321, the welding strength when the current collector protrusion 9321 is welded to the electrode terminal can be further improved.

[0405] The support portion 9322 is configured to connect to the current collector unit 9310. Specifically, the shape of the support portion 9322 corresponds to the shape of the opening 9315 of the connection portion 9313 of the current collector unit 9310, and the support portion 9322 can be inserted into the opening 9315. The thickness h3 of the support portion 9322 can be approximately equal to the depth of the opening 9315, so that when the support portion 9322 is inserted into the opening 9315, the support portion 9322 rests partially on the step portion 9316, thereby making the pole unit 9320 more stably supported on the current collector unit 9310.

[0406] Flange 9323 is located between the current collecting protrusion 9321 and the support portion 9322, and the cross-sectional area of ​​flange 9323 can be larger than that of support portion 9322. This allows the lower surface of flange 9323 to contact the upper surface of connecting portion 9313 of current collecting unit 9310 when support portion 7322 is inserted into opening 7315, preventing support portion 9322 from penetrating deeper than a predetermined depth through opening 9315 and providing more stable support for current collecting protrusion 9321. The cross-sectional area of ​​flange 9323 can be 5-10 times, preferably 10 times, the cross-sectional area of ​​current collecting protrusion 9321. When flange 9323 is formed as a cylinder, the diameter of current collecting protrusion 9321 can be 20% to 50%, preferably 30%, of the diameter of flange 9323. Flange 9323 can protrude from the upper surface of current collecting unit 9310 to form a stop portion, creating a stepped structure in current collector 9300. The upper surface of flange 9323 is formed as a flat surface to support components to be assembled thereon. The thickness (height) h2 of flange 9323 can be calculated using the following formula: h2 = A × 0.005 × B / C, where A is the thickness of electrode assembly 1200, B is the length of electrode tabs, and C is the number of groups of electrode tabs to be welded to the current collector. The thickness h2 of flange 9323 can be equal to or greater than the height of the plurality of first electrode tabs 1220 and the plurality of second electrode tabs 1230 welded to the upper surface of current collector unit 9310 of current collector 9300. The thickness h2 of flange 9323 can be equal to or greater than the thickness h1 of current collector unit 9310. In one example, the thickness h2 of flange 9323 can be 100% to 120% of the thickness h1 of current collector unit 9310. The thickness h2 of the flange 9323 can be 30% to 50% of the height hc of the current collecting protrusion 9321, and preferably 40%.

[0407] The protruding end 9324 protrudes downward from the lower surface of the support portion 9322. The cross-sectional area of ​​the protruding end 9324 is smaller than that of the support portion 9322, thereby forming a step between the peripheral portion 9325 of the support portion 9322 and the protruding end 9324. When the support portion 9322 is inserted into the opening 9315 of the connecting portion 9313 of the collector unit 9310 and connected to the collector unit 9310, the peripheral portion 9325 of the support portion 9322 rests on the step portion 9316 of the collector unit 9310, and the protruding end 9324 is received in the recessed area 9317 of the collector unit 9310. Preferably, the height h4 of the protruding end 9324 protruding from the lower surface of the support portion 9322 can be equal to the depth d1 of the recessed region 9317, such that when the protruding end 9324 is received in the recessed region 9317 of the current collecting unit 9310, the lower surface of the protruding end 9324 is substantially flush with the lower surface of the current collecting unit 9310, such as... Figure 71 and Figure 75 As shown, this is to facilitate the application or attachment of an insulator to the lower surface of the current collector 9310 after the pole unit 9320 is welded to the current collector 9310.

[0408] Welding between current collector 9310 and pole unit 9320 can be performed from the bottom side of current collector 9310. Figure 76 The welding area between current collector 9310 and pole unit 9320 is shown. Welding can be performed between the outer periphery of the protruding end 9324 and the inner periphery of the recessed area 9317 to form welding area A, as shown. Figure 76 As shown.

[0409] Figure 77 A cross-sectional view of a current collector 9300A for a secondary battery according to a modified example of the ninth embodiment of the present disclosure is shown. This modified example current collector 9300A has a substantially identical construction to the current collector 9300 according to the ninth embodiment of the present disclosure, except that the lower surface of the protruding end 9324 is higher than the lower surface of the current collector unit 9310. Therefore, even if weld burrs are generated during welding, the weld burrs will be located within the recessed area 9317 and will not protrude downwards from the lower surface of the current collector unit 9310.

[0410] The current collector of the secondary battery according to the tenth embodiment of this disclosure will now be described. Figure 78 This is a cross-sectional view of the current collector 10300 in a secondary battery according to the tenth embodiment of this disclosure. Figure 79 This is a cross-sectional view of the current collector unit in a secondary battery according to the tenth embodiment of this disclosure. Figure 80 and Figure 81 This is a cross-section of an electrode unit in a secondary battery according to the tenth embodiment of this disclosure. Figure 82This is a view illustrating the process of assembling the current collector and the pole unit in the tenth embodiment of this disclosure.

[0411] The current collector 10300 includes a current collector unit 10310 and an electrode unit 10320. The current collector unit 10310 can be connected to a plurality of electrode tabs. The current collector unit 10310 may have a rectangular shape extending along the longitudinal direction (y-direction) of the electrode assembly. The current collector unit 10310 may include a connecting portion 10313, a first current collector portion 10311, and a second current collector portion 10312 continuously arranged along the longitudinal direction of the rectangular shape. A plurality of first electrode tabs 1220 may be bent and welded to the upper surface of the first current collector portion 10311. A plurality of second electrode tabs 1230 may be bent and welded to the upper surface of the second current collector portion 10312. The current collector unit 10310 has a similar construction to the current collector unit 4310 according to the fourth embodiment of the present disclosure, differing only in the design of the recessed region on the lower surface of the current collector unit 10310.

[0412] like Figure 79 As shown, the connecting portion 10313 has an opening 10315 and a recessed region 103171. The recessed region 103171 is recessed upward from the lower surface of the current collecting unit 10310 and communicates with the opening 10315. The recessed region 10317 has an inclined peripheral wall, such that the cross-sectional area of ​​the recessed region 10317 gradually decreases in the direction (z-direction) toward the opening 10315. The cross-sectional area of ​​the recessed region 10317 at the lower surface of the current collecting unit 10310 is greater than the cross-sectional area of ​​the opening 10315. The depth d1 of the recessed region 10317 can be 5% to 15% of the thickness h1 of the current collecting unit 10310.

[0413] The electrode unit 10320 can be connected to the corresponding electrode terminal. The electrode unit 10320 is connected to the current collector unit 10310 via the opening 10315 of the connection portion 10313 of the current collector unit 10310. The electrode unit 10320 has a similar structure to the electrode unit 4320 of the current collector 4300 of the secondary battery according to the fourth embodiment of this disclosure, the only difference being the design of the current collector protrusion of the electrode unit 10320. For example... Figure 80As shown, the electrode unit 10320 includes a current collector protrusion 10321, a support portion 10322, and a flange 10323. The current collector protrusion 10321 has a predetermined height hc and can be electrically connected to a corresponding electrode terminal. The current collector protrusion 10321 includes a first current collector protrusion 10321a, a second current collector protrusion 10321b, and a connecting portion 10321c. The connecting portion 10321c connects the first current collector protrusion 10321a and the second current collector protrusion 10321b. The connecting portion 10321c is formed with an inclined outer peripheral surface to smoothly connect the first current collector protrusion 10321a and the second current collector protrusion 10321b. The first current collector protrusion 10321a is connected to the flange 10323, and the cross-sectional area of ​​the first current collector protrusion 10321a is larger than the cross-sectional area of ​​the second current collector protrusion 10321b. The second current collector protrusion 10321a, with its smaller cross-sectional area, can be more easily inserted into the terminal hole provided on the cover assembly for electrical connection with the corresponding electrode terminal.

[0414] When the current collector 10300 is used as a negative current collector, the upper end of the current collector protrusion 10321 can be plated with nickel. More specifically, the upper end of the second current collector protrusion 10321b can be plated with nickel to form a nickel plating layer 10326, such as... Figure 81 As shown. Since a nickel plating layer 10326 is formed on the upper end of the current collector protrusion 10321, the welding strength when the current collector protrusion 10321 is welded to the electrode terminal can be further improved.

[0415] The support portion 10322 is configured to be connected to the current collection unit 10310. Specifically, the shape of the support portion 10322 corresponds to the shape of the opening 10315 of the connection portion 10313 of the current collection unit 10310, and the support portion 10322 can be inserted into the opening 10315.

[0416] Flange 10323 is located between the current collecting protrusion 10321 and the support portion 10322, and the cross-sectional area of ​​flange 10323 can be larger than the cross-sectional area of ​​support portion 10322, such that when support portion 10322 is inserted into opening 10315, flange 10323 can protrude from the upper surface of current collecting unit 10310 to form a stop portion, forming a stepped structure in current collector 10300. The lower surface of flange 10323 can contact the upper surface of connecting portion 10313 of current collecting unit 10310, and support portion 10322 can be at least partially received in opening 10315. The cross-sectional area of ​​flange 10323 can be 5-15 times the cross-sectional area of ​​current collecting protrusion 10321, preferably 10 times. When the flange 10323 is formed as a cylinder, the diameter of the current collecting protrusion 10321 can be 20% to 50% of the diameter of the flange 10323, preferably 30%. The thickness (height) h2 of the flange 10323 can be calculated by the following formula: h2 = A × 0.005 × B / C, where A is the thickness of the electrode assembly 1200, B is the length of the electrode tab, and C is the number of groups of electrode tabs to be welded to the current collector. As the number of groups of electrode tabs to be welded to the current collector increases, the thickness h2 of the flange 10323 can decrease. The thickness h2 of the flange 10323 can be equal to or greater than the thickness h1 of the current collecting unit 10310, and can be 100% to 120% of the thickness h1 of the current collecting unit 10310. The thickness h2 of the flange 10323 can be 30% to 50% of the height hc of the current collecting protrusion 10321, and preferably 40%. Figures 78-82 In the example shown, the support portion 10322 is received in the opening 10315 and the recessed region 10317, and the lower surface of the support portion 10322 is flush with the lower surface of the current collection unit 10310. In other examples according to the tenth example of this disclosure, the lower surface of the support portion 10322 may be higher than the lower surface of the current collection unit 10310.

[0417] Furthermore, as described above, the cross-sectional area of ​​the recessed region 10317 at the lower surface of the current collector 10310 is larger than the cross-sectional area of ​​the opening 10315, and correspondingly larger than the cross-sectional area of ​​the support portion 10322. Therefore, when the pole unit 10320 is supported on the current collector 10310, a gap space is formed between the outer peripheral surface of the support portion 10322 and the peripheral wall of the recessed region 10317.

[0418] Welding between current collector 10310 and pole unit 10320 can be performed from the bottom side of current collector 10310. Figure 83The welding area between the current collector 10310 and the pole unit 10320 is shown. Welding can be performed in the gap space between the outer peripheral surface of the support portion 10322 and the peripheral wall of the recessed region 10317 to form the welding area A, as shown. Figure 83 As shown. Even if welding burrs are generated during welding, the welding burrs will be located in the gap space between the outer peripheral surface of the support portion 10322 and the peripheral wall of the recessed region 10317, and will not protrude downward from the lower surface of the current collection unit 10310.

[0419] In the example shown above, groups of electrode contacts of different polarities of the electrode assembly 1200 are all disposed on the same side of the electrode assembly 1200. However, this disclosure is not limited thereto. Figure 84 An exploded perspective view of a secondary battery according to the eleventh embodiment of the present disclosure is shown. Figure 85 A perspective view of the electrode assembly of a secondary battery according to the eleventh embodiment of the present disclosure is shown. The secondary battery according to the eleventh embodiment of the present disclosure uses the same current collector 1300 as the secondary battery according to the first embodiment of the present disclosure, the only difference being that groups of electrode contacts of different polarities are respectively disposed on opposite sides of the electrode assembly, and correspondingly, the opposite ends of the housing 1100 are open, and two cover assemblies 1400 are provided for sealing the openings at the opposite ends of the housing 1100, each cover assembly 1400 having corresponding electrode terminals 1420, 1420a. Figure 85 As shown, groups of electrode contacts 1220 and 1230 with the same polarity are disposed at one end of the electrode assembly 1200, and groups of electrode contacts 1250 and 1260 are disposed at the other end of the electrode assembly 1200.

[0420] Figure 86 A partial perspective view of a secondary battery of a first modification according to the eleventh embodiment of this disclosure is shown. Figure 86 As shown, the secondary battery uses the same current collector 1300A as in the secondary battery of the first modified example according to the first embodiment of the present disclosure. Figure 87 A partial perspective view of a second modified secondary battery according to the eleventh embodiment of this disclosure is shown. Figure 87 As shown, the secondary battery uses the same current collector 1300B as the secondary battery in the second modified example of the first embodiment of the present disclosure. Figure 88 A partial perspective view of a secondary battery according to the eleventh embodiment of this disclosure is shown. Figure 88 As shown, the secondary battery uses the same current collector 1300C as the secondary battery in the second modified example of the first embodiment of the present disclosure.

[0421] A battery module can be constructed by including multiple secondary batteries according to embodiments of the present disclosure. Multiple secondary batteries can be connected to each other via busbars or the like to construct a battery module. Alternatively, a battery pack can be constructed by including multiple battery modules. A battery pack can be constructed by arranging multiple battery modules in an upper battery pack housing and a lower battery pack housing that constitute the battery pack housing. Furthermore, the battery pack can be installed in a vehicle transporting or moving loads or personnel, or in a vehicle moving while performing operations. Such vehicles can include bicycles, heavy equipment, agricultural and fishing equipment, automobiles, buses, and aircraft. Here, the automobile can be an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The automobile can include a four-wheeled vehicle or a two-wheeled vehicle. The vehicle can operate by receiving power from the battery pack.

[0422] The secondary battery according to embodiments of this disclosure can be configured such that welding the electrode tabs to the current collector does not affect the electrode assembly.

[0423] Furthermore, the secondary battery according to embodiments of this disclosure can be configured such that when the electrode tabs and the current collector are welded, a large number of electrode tabs can be stably welded to the current collector.

[0424] Furthermore, the secondary battery according to embodiments of this disclosure can be configured such that the electrode unit can be stably connected to the current collector unit.

[0425] Furthermore, the secondary battery according to embodiments of this disclosure can be configured to simplify the assembly process.

[0426] Although this disclosure has been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes or modifications may be made to this disclosure by adding, altering, or deleting components without departing from the spirit of this disclosure as defined in the following claims. It should be noted that such changes or modifications also fall within the scope of this disclosure.

Claims

1. A secondary battery, comprising: An electrode assembly, the electrode assembly including an electrode portion and a plurality of electrode tabs formed on one end of the electrode portion; as well as A current collector, wherein the current collector is disposed on one end of the electrode portion and welded to the electrode tab. The current collector includes: A current collector unit, comprising a first current collector portion, a second current collector portion, and a connecting portion, wherein the first current collector portion is soldered to a plurality of first electrode contacts among the plurality of electrode contacts, the second current collector portion is soldered to a plurality of second electrode contacts among the plurality of electrode contacts, the second electrode contacts and the first electrode contacts having the same polarity, and the connecting portion is connected to the first current collector portion and has an opening formed therein; and The pole unit is connected to the current collector unit and includes a current collector protrusion and a support portion connected to the lower end of the current collector protrusion, wherein the cross-sectional area of ​​the support portion is larger than the cross-sectional area of ​​the current collector protrusion. The current collector includes a stop portion, which forms a stepped structure within the current collector.

2. The secondary battery according to claim 1, wherein, The lower surface of the current collection unit has a recessed area, and the opening of the connecting portion and the recessed area are joined together in the thickness direction of the connecting portion to penetrate the connecting portion.

3. The secondary battery according to claim 1 or 2, wherein, The stop portion is disposed on the connecting portion and has the opening formed therein.

4. The secondary battery according to claim 3, wherein, The support portion is received in the recessed area.

5. The secondary battery according to claim 4, wherein, The lower surface of the current collection unit is flush with the lower surface of the support portion.

6. The secondary battery according to claim 1, wherein, The upper surface of the stop portion is flush with the upper surface of the support portion.

7. The secondary battery according to claim 3, wherein, The stop portion has a square plate shape, a rectangular plate shape, or a disc shape.

8. The secondary battery according to claim 3, wherein, The stop portion is integrally formed with the connecting portion.

9. The secondary battery according to claim 3, wherein, The height of the stop portion is in the range of 30% to 50% of the height of the end of the current collecting unit.

10. The secondary battery according to claim 3, wherein, The height of the stop portion is in the range of 1% to 5% of the thickness of the electrode assembly.

11. The secondary battery according to claim 2, wherein, The depth of the recessed area is in the range of 30% to 50% of the height of the end of the current collection unit.

12. The secondary battery according to claim 2, in, The recessed area is formed below the stop portion, and The cross-sectional area of ​​the recessed region is smaller than the cross-sectional area of ​​the stop portion.

13. The secondary battery according to claim 12, wherein, The depth of the recessed region is equal to the height of the end of the current collection unit.

14. The secondary battery according to claim 12, wherein, The outer peripheral surface of the flow collecting protrusion and the inner peripheral surface of the opening of the stop portion are spaced apart by a predetermined distance.

15. The secondary battery according to claim 12, wherein, The outer peripheral surface of the support portion and the inner peripheral surface of the recessed region are spaced apart by a predetermined distance.

16. The secondary battery according to claim 1 or 2, wherein, The pole unit further includes a flange formed between the current collecting protrusion and the support portion, the pole unit being connected to the current collecting unit such that the flange is mounted on the connecting portion to form the stop portion.

17. The secondary battery according to claim 16, wherein, The support portion is inserted into the opening.

18. The secondary battery according to claim 2, wherein, The lower surface of the support portion is positioned above the lower surface of the current collection unit.

19. The secondary battery according to claim 16, wherein, The flange has a square plate shape, a rectangular plate shape, or a disc shape.

20. The secondary battery according to claim 16, wherein, The flow collecting protrusion, the support portion, and the flange are integrally formed.

21. The secondary battery according to claim 16, wherein, The height of the flange is in the range of 30% to 50% of the height of the end of the current collector unit.

22. The secondary battery according to claim 16, wherein, The height of the flange is in the range of 1% to 5% of the thickness of the electrode assembly.

23. The secondary battery according to claim 2, wherein, A welding area is formed on the periphery of the lower surface of the support portion to weld the pole unit and the current collector unit together.

24. The secondary battery according to claim 2, wherein, A welding area is formed on the entire lower surface of the support portion. The welding area includes a first welding area formed on the periphery of the lower surface of the support portion and a second welding area located inside the first welding area. The laser output of the first welding area is higher than the laser output of the second welding area.

25. The secondary battery according to claim 1, wherein, The material of the current collector unit may be the same as or different from the material of the pole unit.

26. The secondary battery according to claim 16, wherein, The pole unit further includes a protruding end, the protruding end and the flange being located on opposite sides of the support portion, and the cross-sectional area of ​​the protruding end being smaller than the cross-sectional area of ​​the support portion.

27. The secondary battery according to claim 1, wherein, The current collector is used as a negative current collector, and a nickel plating is formed on the upper end of the current collector protrusion.

28. The secondary battery according to claim 1, wherein, The support portion is partially located in the opening, and a portion of the support portion protrudes from the connecting portion to form the stop.

29. The secondary battery according to claim 1, wherein, The first collection section, the second collection section, and the connection section are arranged in any of the following ways: The first current collection section, the second current collection section, and the connecting section are arranged continuously along the longitudinal direction of the current collection unit; The first current collection section, the connecting section, and the second current collection section are arranged continuously along the longitudinal direction of the current collection unit; The first current collection section and the second current collection section are respectively connected to the two ends of the same side of the connecting section.

30. The secondary battery according to claim 26, wherein, The cross-sectional area of ​​the recessed region on the lower surface of the current collection unit is smaller than the cross-sectional area of ​​the opening, so that a step is formed between the opening and the recessed region.

31. The secondary battery according to claim 30, wherein, The support portion rests partially on the stepped portion, and the protruding end is received in the recessed area.

32. The secondary battery according to claim 31, wherein, The lower surface of the protruding end is flush with or higher than the lower surface of the current collecting unit.

33. The secondary battery according to claim 16, wherein, The recessed area on the lower surface of the current collection unit has an inclined peripheral wall, such that the cross-sectional area of ​​the recessed area gradually decreases in the direction toward the opening.

34. The secondary battery according to claim 33, wherein, The current collecting protrusion includes a first current collecting protrusion, a second current collecting protrusion, and a connecting portion. The connecting portion connects the first current collecting protrusion and the second current collecting protrusion. The first current collecting protrusion is connected to the flange, and the cross-sectional area of ​​the first current collecting protrusion is larger than the cross-sectional area of ​​the second current collecting protrusion.

35. The secondary battery according to claim 1 or 2, wherein, The pole unit is connected to the current collector unit such that the lower surface of the pole unit is lower than the upper surface of the current collector unit.

36. The secondary battery according to claim 1 or 2, wherein, The cross-sectional area of ​​the support portion is in the range of 150% to 300% of the cross-sectional area of ​​the flow collecting protrusion.

37. The secondary battery according to claim 1 or 2, wherein, The plurality of first electrode contacts are bent toward the upper surface of the first current collecting portion, and the plurality of second electrode contacts are bent toward the upper surface of the second current collecting portion in a direction opposite to the bending direction of the plurality of first electrode contacts. as well as The spacing between the first electrode contact and the second electrode contact is 5% to 15% of the length of the current collector.

38. The secondary battery according to claim 37, wherein, The plurality of first electrode contacts are welded to the first current collector, and the plurality of second electrode contacts are welded to the second current collector.

39. The secondary battery according to claim 1 or 2, wherein, The secondary battery also includes: A housing, wherein the electrode assembly is housed within the housing, and an opening is formed at one end of the housing; and A cover assembly that seals the opening of the housing and includes a cover plate and electrode terminals. The current collector protrusion is inserted into the through hole of the electrode terminal.

40. The secondary battery according to claim 39, wherein, The flow collecting protrusion is welded to the through hole at its end.

41. A secondary battery, comprising: An electrode assembly, the electrode assembly including an electrode portion and a plurality of electrode tabs formed on one end of the electrode portion; as well as A current collector, wherein the current collector is disposed on one end of the electrode portion and welded to the electrode tab. The current collector includes: A current collector unit, comprising a first current collector portion, a second current collector portion, and a connecting portion, wherein the first current collector portion is soldered to a plurality of first electrode contacts among a plurality of electrode contacts, the second current collector portion is soldered to a plurality of second electrode contacts among the plurality of electrode contacts, the second electrode contacts and the first electrode contacts having the same polarity, and the connecting portion is connected to the first current collector portion and includes a seating area formed in the upper surface of the connecting portion; and The pole unit is connected to the current collector unit and includes a current collector protrusion. The current collector includes a stop portion, which forms a stepped structure within the current collector.

42. The secondary battery according to claim 41, wherein, The seating area is recessed downward from the upper surface of the connecting portion, and the depth of the seating area is in the range of 30% to 50% of the height of the end of the current collection unit.

43. The secondary battery according to claim 42, wherein, The pole unit also includes a support portion connected to the lower end of the current collecting protrusion and seated in the seating area; A portion of the support portion protrudes from the upper surface of the connecting portion to form the stop portion.

44. The secondary battery according to claim 43, wherein, The height at which the support portion protrudes from the upper surface of the current collector unit is in the range of 1% to 5% of the thickness of the electrode assembly.

45. The secondary battery according to claim 43, wherein, The supporting part has a square plate shape, a rectangular plate shape, or a disc shape.

46. ​​The secondary battery according to claim 43, wherein, The pole unit is connected to the current collector unit such that the lower surface of the pole unit is lower than the upper surface of the current collector unit.

47. The secondary battery according to claim 43, wherein, The cross-sectional area of ​​the support portion is in the range of 150% to 300% of the cross-sectional area of ​​the flow collecting protrusion.

48. The secondary battery according to claim 41, wherein, The connecting portion is connected to one side of the first collector portion and protrudes relative to the upper surface of the first collector portion, forming the stop portion.

49. The secondary battery according to claim 48, wherein, The upper surface of the seating area is flush with the upper surface of the connecting portion and is connected to the lower surface of the collecting protrusion.

50. The secondary battery according to claim 48, wherein, The height at which the connecting portion protrudes relative to the first current collector portion is within the range of 1% to 5% of the thickness of the electrode assembly.

51. The secondary battery according to claim 50, wherein, The surface of the connection between the connecting portion and the first current collecting portion is inclined.

52. The secondary battery according to claim 48, wherein, The thickness of the connecting portion is equal to the thickness of each of the first current collection portion and the second current collection portion.

53. The secondary battery according to claim 41, wherein, A welding area is formed in the lower surface of the connecting portion corresponding to the seating area.

54. The secondary battery according to claim 53, wherein, The welding area includes a first welding area corresponding to the periphery of the lower surface of the pole unit.

55. The secondary battery according to claim 54, wherein, The welding area also includes a second welding area located inside the first welding area, wherein the laser output of the first welding area is higher than the laser output of the second welding area.

56. The secondary battery according to claim 41, wherein, The material of the current collector unit may be the same as or different from the material of the pole unit.

57. The secondary battery according to claim 41, wherein, The current collector is used as a negative current collector, and a nickel plating is formed on the upper end of the current collector protrusion.

58. The secondary battery according to claim 41, wherein, In the current collection unit, the first current collection section, the second current collection section, and the connection section are arranged in any of the following ways: The connecting portion is connected to one side of the first current collecting portion, and the second current collecting portion is connected to the opposite side of the first current collecting portion; The connecting portion is disposed between the first current collection portion and the second current collection portion; The first current collection portion is connected to the upper end of one side of the connecting portion, and the second current collection portion is connected to the lower end of the one side of the connecting portion.

59. The secondary battery according to any one of claims 41-58, wherein, The plurality of first electrode contacts are bent toward the upper surface of the first current collection portion of the current collection unit of the current collector, and the plurality of second electrode contacts are bent toward the upper surface of the second current collection portion of the current collection unit in a direction opposite to the bending direction of the plurality of first electrode contacts. as well as The spacing between the first electrode contact and the second electrode contact is 5% to 15% of the length of the current collector.

60. The secondary battery according to claim 59, wherein, The plurality of first electrode contacts are welded to the first current collector, and the plurality of second electrode contacts are welded to the second current collector.

61. The secondary battery according to any one of claims 41-58, wherein, The secondary battery also includes: A housing, wherein the electrode assembly is housed within the housing, and an opening is formed at one end of the housing; and A cover assembly that seals the opening of the housing and includes a cover plate and electrode terminals. The current collector protrusion is inserted into the through hole of the electrode terminal.

62. The secondary battery according to claim 41, wherein, The flow collecting protrusion is welded to the through hole at its end.

63. A method for manufacturing a secondary battery, said secondary battery being a secondary battery according to any one of claims 1-62, said method comprising: An electrode assembly is prepared, the electrode assembly including an electrode portion and a plurality of electrode tabs formed on one end of the electrode portion; The plurality of first electrode contacts are welded together, and the plurality of second electrode contacts are welded together, wherein the first electrode contacts and the second electrode contacts have the same polarity; Provide the current collector and arrange the current collector between the plurality of first electrode contacts and the plurality of second electrode contacts; The plurality of first electrode contacts are bent toward the upper surface of the first current collection portion of the current collection unit of the current collector, and the plurality of second electrode contacts are bent toward the upper surface of the second current collection portion of the current collection unit. as well as The plurality of first electrode contacts are welded to the upper surface of the first current collector, and the plurality of second electrode contacts are welded to the upper surface of the second current collector.

64. The method for manufacturing a secondary battery according to claim 63, wherein, Providing the current collector includes: connecting the pole units of the current collector to the connection portion of the current collector unit, and performing welding on a welding area on the lower surface of the current collector to weld the pole units and the current collector unit together.

65. The method for manufacturing a secondary battery according to claim 64, wherein, Connecting the current collector's pole unit to the connection portion includes: The pole unit is connected from below the current collector unit to the connecting portion, such that the current collector protrusion of the pole unit passes through the opening of the connecting portion and protrudes from the upper surface of the connecting portion, and the lower surface of the pole unit is positioned flush with or higher than the lower surface of the current collector unit.

66. The method for manufacturing a secondary battery according to claim 64, wherein, Connecting the current collector's pole unit to the connection portion includes: The pole unit is connected downwards to the connection portion from above, such that the current collecting protrusion of the pole unit protrudes from the upper surface of the connection portion.

67. The method for manufacturing a secondary battery according to claim 66, wherein, The support portion of the pole unit is at least partially accommodated within the opening or seating area of ​​the connecting portion.

68. The method of manufacturing a secondary battery according to any one of claims 64-66, wherein, The welding area includes a first welding area corresponding to the periphery of the lower surface of the pole unit.

69. The method for manufacturing a secondary battery according to claim 68, wherein, The welding area also includes a second welding area located inside the first welding area, wherein the laser output used for welding in the first welding area is higher than the laser output used for welding in the second welding area.

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