Secondary battery and manufacturing method therefor

Abstract

The present invention relates to a secondary battery and a manufacturing method therefor. A secondary battery according to an embodiment of the present invention comprises a case, an electrode assembly, a current collector, and a cap assembly. The electrode assembly is accommodated in the case and comprises an electrode portion, a plurality of first electrode tabs, and a plurality of second electrode tabs. The current collector comprises a first current collecting portion, a second current collecting portion, and a connecting portion. The cap assembly is coupled to one end of the case. The plurality of first and second electrode tabs may be bent and welded onto the first current collecting portion and the second current collecting portion of the current collector, respectively.

Description

Secondary battery and its manufacturing method

[0001] The present invention relates to a secondary battery and a method for manufacturing the same, and more particularly, to a secondary battery and a method for manufacturing the same, in which a plurality of first electrode tabs and a plurality of second electrode tabs are welded to a first current collector portion and a second current collector portion of a current collector, respectively.

[0002] Recently, with the rapid increase in demand for portable electronic products and the full-scale development of electric vehicles, energy storage batteries, robots, satellites, etc., research on high-performance secondary batteries capable of repeated charging and discharging is actively being conducted.

[0003] Secondary batteries can be classified into can-type secondary batteries, in which the electrode assembly is housed in a metal can, and pouch-type secondary batteries, in which the electrode assembly is housed in a pouch made of aluminum laminate sheet, depending on the shape of the battery case. Can-type secondary batteries can be classified into cylindrical secondary batteries and square secondary batteries, depending on the shape of the metal can.

[0004] Secondary batteries are connected by welding the electrode tabs and current collectors of the electrode assembly. When welding the electrode tabs and current collectors, the electrode tabs are bent in the bending direction to increase the contact area between the electrode tabs and the current collector, and then the current collector is placed on top of the electrode tabs and welded.

[0005] However, in this case, there is a risk of damage to the separator during the welding process between the current collector and the electrode tabs positioned beneath it. Furthermore, as secondary batteries increase in capacity, the number of electrode tabs that must be welded simultaneously increases, raising concerns that tabs located far from the current collector may not be properly welded.

[0006] Accordingly, there is a need to develop a secondary battery that can stably weld a large number of electrode tabs to a current collector without concern for damage to the separator.

[0007] The purpose of the present invention is to provide a secondary battery and a method for manufacturing the same, which can prevent an electrode assembly from being affected when welding an electrode tab and a current collector.

[0008] The purpose of the present invention is to provide a secondary battery and a method for manufacturing the same, which can stably weld a large number of electrode tabs to a current collector when welding the electrode tabs and the current collector.

[0009] The purpose of the present invention is to provide a secondary battery and a method for manufacturing the same, which can weld electrode tabs and a current collector so that no electrode tab among a plurality of electrode tabs is unwelded.

[0010] An object of the present invention is to provide a secondary battery and a method for manufacturing the same, which can prevent interference between different electrode tab assemblies welded to a current collector at positions spaced apart from each other.

[0011] A secondary battery according to one embodiment of the present invention includes an electrode assembly and a current collector. The electrode assembly may include an electrode portion, a plurality of first electrode tabs formed at one end of the electrode portion, and a plurality of second electrode tabs. The current collector may be disposed on an upper portion of the electrode portion and may include a first current collector welded to the plurality of first electrode tabs, a second current collector welded to the plurality of second electrode tabs, and a connecting portion disposed between the first current collector and the second current collector and having a current collector protrusion. The plurality of first electrode tabs may be bent in one direction toward the first current collector of the current collector, and the plurality of second electrode tabs may be bent in the opposite direction of the first electrode tab toward the second current collector of the current collector.

[0012] In a secondary battery according to one embodiment of the present invention, a plurality of first electrode tabs may be bent in one direction toward a first current collector of a current collector, and a plurality of second electrode tabs may be bent in an opposite direction to the first electrode tabs toward a second current collector of a current collector, and may be welded respectively.

[0013] According to one embodiment of the present invention, a current collector includes a first surface facing the electrode portion and a second surface opposite the first surface, and at least a portion of the first surface may be positioned between the first electrode tab and the second electrode tab. The first electrode tab and the second electrode tab may be positioned at offset positions with the current collector interposed therebetween, and may be bent toward the second surface and welded to the second surface.

[0014] In a secondary battery according to one embodiment of the present invention, the electrode portion may include a plurality of first electrode members having first electrode tabs formed at first positions, and a plurality of second electrode members having second electrode tabs formed at second positions. The first electrode members and the second electrode members may have the same polarity.

[0015] In a secondary battery according to one embodiment of the present invention, a plurality of first electrode tabs and a plurality of second electrode tabs may be spaced apart in the width direction (y direction) and the length direction (x direction) of the electrode assembly.

[0016] In a secondary battery according to one embodiment of the present invention, a plurality of first electrode tabs may be pre-welded to each other, and a plurality of second electrode tabs may be pre-welded to each other.

[0017] In a secondary battery according to one embodiment of the present invention, a first current collector and a second current collector may be arranged in the longitudinal direction of an electrode assembly.

[0018] According to one embodiment of the present invention, a current collector may further include a connecting portion disposed between the first current collector and the second current collector, and having a current collector projection.

[0019] According to one embodiment of the present invention, a current collector may further include a current collector edge disposed on one side of the first current collector portion and having a current collector protrusion.

[0020] In a secondary battery according to one embodiment of the present invention, a current collector may be disposed between a plurality of first electrode tabs and a plurality of second electrode tabs.

[0021] In a secondary battery according to one embodiment of the present invention, a protective layer may be disposed on the lower portion of the current collector.

[0022] In a secondary battery according to one embodiment of the present invention, the thickness of the current collector may be 0.5 to 3.0 mm.

[0023] A secondary battery according to one embodiment of the present invention may further include a cover member that covers the first and second electrode tabs each welded to a current collector.

[0024] In a secondary battery according to one embodiment of the present invention, the current collector protrusion may be formed of the same material as the first and second current collector portions.

[0025] In a secondary battery according to one embodiment of the present invention, the current collector protrusion may be formed of a material different from that of the first and second current collector portions.

[0026] In a secondary battery according to one embodiment of the present invention, the electrode portion may include a separator positioned between each of a plurality of first electrode members and a plurality of second electrode members. The electrode assembly may be formed by stacking or winding a plurality of first electrode members, a plurality of second electrode members, and a separator.

[0027] A secondary battery according to one embodiment of the present invention may further include a case and a cap assembly. The case may have one end open and accommodate an electrode assembly. The cap assembly may be coupled to one end of the case and may include an electrode terminal electrically connected to a current collector.

[0028] In a secondary battery according to one embodiment of the present invention, the electrode terminal may be provided with a through hole. A current collecting protrusion may be inserted into the through hole of the electrode terminal.

[0029] A method for manufacturing a secondary battery according to one embodiment of the present invention includes a preparation step in which an electrode assembly is prepared, which includes an electrode portion, a plurality of first electrode tabs formed at one end of the electrode portion, and a plurality of second electrode tabs, a first welding step in which a plurality of first electrode tabs are welded to each other and a plurality of second electrode tabs are welded to each other, a current collector arrangement step in which a current collector is arranged between the plurality of first electrode tabs and the plurality of second electrode tabs that are firstly welded, a bending step in which the plurality of first electrode tabs are bent to an upper surface of the first current collector portion of the current collector, and the plurality of second electrode tabs are bent to an upper surface of the second current collector portion of the current collector, and a second welding step in which the plurality of first electrode tabs are welded to a first current collector portion and the plurality of second electrode tabs are welded to a second current collector portion, respectively.

[0030] In a method for manufacturing a secondary battery according to one embodiment of the present invention, a plurality of first electrode tabs and a plurality of second electrode tabs may have the same polarity.

[0031] In a method for manufacturing a secondary battery according to one embodiment of the present invention, the current collector may include a first current collector and a second current collector arranged in the longitudinal direction of the electrode assembly.

[0032] In a method for manufacturing a secondary battery according to one embodiment of the present invention, a protective layer may be disposed on the lower portion of the current collector.

[0033] In a method for manufacturing a secondary battery according to one embodiment of the present invention, the current collector may have a current collector protrusion formed of a different material from the first current collector and the second current collector between the first current collector and the second current collector.

[0034] In a method for manufacturing a secondary battery according to one embodiment of the present invention, the current collector may have a current collector protrusion formed of the same material as the first current collector and the second current collector between the first current collector and the second current collector.

[0035] A secondary battery according to an embodiment of the present invention comprises: a plurality of first electrode members, each including a first electrode tab; a plurality of second electrode members, each including a second electrode tab; a plurality of third electrode members, each including a third electrode tab; a plurality of fourth electrode members, each including a fourth electrode tab; an electrode assembly having a length in a first direction and a width in a second direction perpendicular to the first direction, wherein the plurality of first electrode members and the plurality of second electrode members are stacked and formed, a second stack portion formed by stacking the plurality of third electrode members and the plurality of fourth electrode members and stacking the first stack portion and the second direction; a first electrode tab assembly formed by combining the first electrode tabs of each of the plurality of first electrode members and forming a first stack portion, and positioned in a first region among a plurality of regions of the electrode assembly divided in the first direction; a second electrode tab assembly formed by combining the second electrode tabs of each of the plurality of second electrode members and forming a first stack portion, and different from the first region among a plurality of regions of the electrode assembly divided in the first direction. It may include a second electrode tab assembly positioned in the area.

[0036] A secondary battery according to one embodiment of the present invention may include a plurality of first electrode members, each of which includes a first electrode tab.

[0037] A secondary battery according to one embodiment of the present invention may include a plurality of second electrode members, each of which includes a second electrode tab and has the same polarity as the plurality of first electrode members.

[0038] A secondary battery according to one embodiment of the present invention may include an electrode assembly formed by stacking the plurality of first electrode members and the plurality of second electrode members, and having a length in a first direction and a width in a second direction perpendicular to the first direction.

[0039] A secondary battery according to one embodiment of the present invention may include a terminal that connects the electrode assembly to an external device.

[0040] A secondary battery according to one embodiment of the present invention may include a current collector including a first current collector, a second current collector spaced apart from the first current collector in the first direction, and a current collector protrusion formed between the first current collector and the second current collector and connected to the terminal.

[0041] According to one embodiment of the present invention, the first electrode tab of each of the plurality of first electrode members may be bent in the second direction and welded to the first current collector, the second electrode tab of each of the plurality of second electrode members may be bent in the second direction and welded to the second current collector, and the current collector protrusion may be positioned between the first electrode tab and the second electrode tab.

[0042] A secondary battery according to one embodiment of the present invention may include a first electrode tab assembly formed by combining the first electrode tabs of each of the plurality of first electrode members with each other and welded to the first current collector.

[0043] A secondary battery according to one embodiment of the present invention may include a second electrode tab assembly formed by joining the second electrode tabs of each of the plurality of second electrode members to each other and welded to the second current collector.

[0044] According to one embodiment of the present invention, at least a portion of the first electrode tab assembly and at least a portion of the second electrode tab assembly may be bent in opposite directions and welded to the current collector.

[0045] According to one embodiment of the present invention, the current collector may include a lower surface facing the electrode assembly.

[0046] The collector according to one embodiment of the present invention may include an upper surface facing the terminal.

[0047] According to one embodiment of the present invention, the first electrode tab assembly and the second electrode tab assembly can be welded to the upper surface of the current collector.

[0048] According to one embodiment of the present invention, the first electrode tab assembly may include a first assembly welding portion formed by connecting the first electrode tabs of each of the plurality of first electrode members to each other, and a first-1 assembly portion welded to the first current collector.

[0049] The second electrode tab assembly according to one embodiment of the present invention may include a second assembly welding portion formed in which the second electrode tabs of each of the plurality of second electrode members are joined to each other, and a second-1 assembly portion welded to the second current collector.

[0050] The first electrode tab assembly according to one embodiment of the present invention may include a first-second assembly portion positioned between the first current collector and the electrode assembly.

[0051] The second electrode tab assembly according to one embodiment of the present invention may include a 2-2 assembly portion positioned between the second current collector and the electrode assembly.

[0052] According to one embodiment of the present invention, the first electrode tab assembly may include a 1-3 assembly portion extending away from the current collector.

[0053] According to one embodiment of the present invention, the second electrode tab assembly may include a 2-3 assembly portion extending away from the current collector.

[0054] According to one embodiment of the present invention, the current collector may include a connecting portion, at least part of which is positioned between the first electrode tab and the second electrode tab, and from which the current collector protrusion protrudes.

[0055] According to one embodiment of the present invention, the first electrode tab and the second electrode tab may be spaced apart from each other along the first direction.

[0056] The electrode assembly according to one embodiment of the present invention may include a bridge portion formed between the first electrode tab and the second electrode tab.

[0057] According to one embodiment of the present invention, the current collector protrusion may protrude toward the terminal at a position corresponding to the bridge portion.

[0058] A secondary battery according to one embodiment of the present invention may include a plurality of second electrode members, each of which includes a second electrode tab.

[0059] A secondary battery according to one embodiment of the present invention may include an electrode assembly having a length in a first direction and a width in a second direction perpendicular to the first direction, and including a first stack portion formed by stacking a plurality of first electrode members, and a second stack portion formed by stacking a plurality of second electrode members and stacked with the first stack portion in the second direction.

[0060] A secondary battery according to one embodiment of the present invention may include a first electrode tab assembly formed in the first stack portion by combining the first electrode tabs of each of the plurality of first electrode members, and positioned in a first region among the plurality of regions of the electrode assembly divided in the first direction.

[0061] A secondary battery according to one embodiment of the present invention may include a second electrode tab assembly formed in the second stack portion by combining the second electrode tabs of each of the plurality of second electrode members, and positioned in a second region different from the first region among the plurality of regions of the electrode assembly divided in the first direction.

[0062] According to one embodiment of the present invention, at least a portion of the first electrode tab assembly and at least a portion of the second electrode tab assembly may be non-overlapping in the first direction.

[0063] According to one embodiment of the present invention, the first electrode tab assembly and the second electrode tab assembly may be non-overlapping in the second direction.

[0064] A secondary battery according to one embodiment of the present invention may include a current collector welded to the first electrode tab assembly and the second electrode tab assembly.

[0065] The electrode assembly according to one embodiment of the present invention may include a bridge portion formed between the first electrode tab assembly and the second electrode tab assembly, which are spaced apart from each other, and facing at least a portion of the current collector.

[0066] According to one embodiment of the present invention, the first electrode tab assembly may include a first-1 assembly portion bent toward the second stack portion.

[0067] The second electrode tab assembly according to one embodiment of the present invention may include a second-1 assembly portion bent toward the first stack portion.

[0068] A secondary battery according to one embodiment of the present invention may include a first electrode tab assembly formed by welding the first electrode tabs of each of the plurality of first electrode members to each other.

[0069] A secondary battery according to one embodiment of the present invention may include a second electrode tab assembly formed by welding the second electrode tabs of each of the plurality of second electrode members to each other.

[0070] A secondary battery according to one embodiment of the present invention may include a current collector to which the first electrode tab assembly and the second electrode tab assembly are welded.

[0071] According to one embodiment of the present invention, the first electrode tab assembly may include a first assembly welding portion formed by welding the first electrode tabs of each of the plurality of first electrode members to each other.

[0072] The first electrode tab assembly according to one embodiment of the present invention may include a first current collector welding portion formed by welding to the current collector.

[0073] The second electrode tab assembly according to one embodiment of the present invention may include a second assembly welding portion formed by welding the second electrode tabs of each of the plurality of second electrode members to each other.

[0074] The second electrode tab assembly according to one embodiment of the present invention may include a second current collector welding portion formed by welding to the current collector.

[0075] The first electrode tab assembly according to one embodiment of the present invention may include a 1-1 assembly portion in which the first assembly welding portion and the first current collector welding portion are formed.

[0076] The second electrode tab assembly according to one embodiment of the present invention may include a second-1 assembly portion in which the second assembly welding portion and the second current collector welding portion are formed.

[0077] A secondary battery according to one embodiment of the present invention may include an electrode assembly formed by stacking the plurality of first electrode members and the plurality of second electrode members.

[0078] The first electrode tab assembly according to one embodiment of the present invention may include a first-second assembly portion positioned between the first current collector welding portion and the electrode assembly.

[0079] The second electrode tab assembly according to one embodiment of the present invention may include a 2-2 assembly portion positioned between the second current collector welding portion and the electrode assembly.

[0080] According to one embodiment of the present invention, the current collector may include a first current collector portion positioned between the first current collector welding portion and the first-second assembly portion.

[0081] According to one embodiment of the present invention, the current collector may include a second current collector portion positioned between the second current collector welding portion and the second-2 assembly portion.

[0082] According to one embodiment of the present invention, the current collector may include a lower surface facing the electrode assembly.

[0083] According to one embodiment of the present invention, the current collector may include a first welding surface facing in a direction opposite to the lower surface, and in which the first assembly welding portion and the first current collector welding portion are joined.

[0084] According to one embodiment of the present invention, the current collector may include a second welding surface facing in a direction opposite to the lower surface, and in which the second assembly welding portion and the second current collector welding portion are joined.

[0085] A secondary battery according to one embodiment of the present invention may include an electrode assembly formed by stacking the plurality of first electrode members and the plurality of second electrode members.

[0086] A secondary battery according to one embodiment of the present invention may include a current collector including a first side facing the electrode assembly and a second side opposite to the first side, at least a portion of which is positioned between the first electrode tab and the second electrode tab.

[0087] According to one embodiment of the present invention, the first electrode tab and the second electrode tab can be welded to the second surface at offset positions with respect to the current collector.

[0088] According to one embodiment of the present invention, the first electrode tab assembly and the second electrode tab assembly can be welded to the second surface at non-overlapping positions in the width direction of the current collector.

[0089] According to one embodiment of the present invention, the collector may include a first welding surface forming at least a portion of the second surface.

[0090] According to one embodiment of the present invention, the current collector may include a second welding surface that forms at least a portion of the second surface and is spaced apart from the first welding surface.

[0091] According to one embodiment of the present invention, the first electrode tab assembly may be welded to the first welding surface, and the second electrode tab assembly may be welded to the second welding surface.

[0092] A secondary battery according to one embodiment of the present invention may include an insulating member, at least part of which is disposed between the current collector and the electrode assembly and covers at least a part of the first-first assembly portion and at least a part of the second-first assembly portion.

[0093] According to one embodiment of the present invention, the current collector may include a current collector protrusion formed between the first and second electrode tabs and an edge of the electrode assembly.

[0094] A secondary battery according to one embodiment of the present invention may include a cover member that covers the first and second electrode tabs welded to the current collector.

[0095] A secondary battery and a manufacturing method thereof according to an embodiment of the present invention can prevent damage to a separator during welding of an electrode tab and a current collector.

[0096] A secondary battery and a manufacturing method thereof according to an embodiment of the present invention can prevent unwelded portions from occurring in some electrode tabs when welding a large number of electrode tabs and a current collector.

[0097] A secondary battery and a manufacturing method thereof according to an embodiment of the present invention can prevent the occurrence of unwelded portions by first welding a plurality of electrode tabs to each other and then secondarily welding them to a current collector.

[0098] A secondary battery and a manufacturing method thereof according to an embodiment of the present invention can prevent interference between the first electrode tab assembly and the second electrode tab assembly by welding the first electrode tab assembly and the second electrode tab assembly, which are welded to the first current collector and the second current collector, respectively, to the current collector at positions spaced apart from each other.

[0099] FIG. 1 is a drawing showing a secondary battery according to one embodiment of the present invention.

[0100] FIG. 2 is a drawing showing a secondary battery according to one embodiment of the present invention.

[0101] FIG. 3 is a drawing showing an electrode assembly in which a plurality of first and second electrode tabs are formed on an electrode portion in a secondary battery according to one embodiment of the present invention.

[0102] FIG. 4 is a drawing showing a first electrode member and a second electrode member in a secondary battery according to one embodiment of the present invention.

[0103] FIG. 5 is a drawing showing a third electrode member and a fourth electrode member in a secondary battery according to one embodiment of the present invention.

[0104] FIG. 6 is a drawing showing a current collector in a secondary battery according to one embodiment of the present invention.

[0105] FIG. 7 is a drawing showing a current collector in a secondary battery according to one embodiment of the present invention.

[0106] Figure 8 is a flowchart showing a method for manufacturing a secondary battery according to one embodiment of the present invention.

[0107] FIG. 9 is a drawing showing a state in which a plurality of first electrode tabs and a plurality of second electrode tabs are each grouped in a secondary battery according to one embodiment of the present invention.

[0108] FIG. 10 is a drawing showing a state in which a plurality of first electrode tabs and a plurality of second electrode tabs are each firstly welded in a secondary battery according to one embodiment of the present invention.

[0109] FIG. 11 is a drawing showing a state in which a current collector is arranged between a plurality of first electrode tabs and a plurality of second electrode tabs in a secondary battery according to one embodiment of the present invention.

[0110] FIG. 12 is a drawing showing a state in which a current collector and first and second electrode tabs are welded in a secondary battery according to one embodiment of the present invention.

[0111] FIG. 13 is a drawing showing a state in which a cap assembly is coupled to an electrode assembly in a secondary battery according to one embodiment of the present invention.

[0112] Figure 14 is a flowchart showing a method for manufacturing a secondary battery according to another embodiment of the present invention.

[0113] FIG. 15 is a drawing showing a state in which a plurality of first electrode tabs and a plurality of second electrode tabs are each grouped in a secondary battery according to another embodiment of the present invention.

[0114] Fig. 16 is a cross-sectional view taken along the F-F' reference line shown in Fig. 15.

[0115] FIG. 17 is a drawing showing a state in which a current collector is arranged between a plurality of first electrode tabs and a plurality of second electrode tabs in a secondary battery according to another embodiment of the present invention.

[0116] FIG. 18 is a drawing showing a state in which a current collector and first and second electrode tabs are welded in a secondary battery according to another embodiment of the present invention.

[0117] FIG. 19 is a drawing showing a state in which a cover member is arranged in a secondary battery according to another embodiment of the present invention.

[0118] Fig. 20 is a cross-sectional view taken along the G-G' reference line shown in Fig. 19.

[0119] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0120] The terminology used herein is merely used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In the present invention, it should be understood that the terms "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0121] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Please note that, where possible, identical components are represented by identical reference numerals throughout the drawings. Furthermore, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted.

[0122]

[0123] FIG. 1 is a drawing showing a secondary battery according to an embodiment of the present invention, FIG. 2 is a drawing showing a secondary battery according to an embodiment of the present invention, FIG. 3 is a drawing showing an electrode assembly having a plurality of first and second electrode tabs formed on an electrode portion in a secondary battery according to an embodiment of the present invention, FIG. 4 is a drawing showing a first electrode member and a second electrode member in a secondary battery according to an embodiment of the present invention, FIG. 5 is a drawing showing a third electrode member and a fourth electrode member in a secondary battery according to an embodiment of the present invention, FIG. 6 is a drawing showing a current collector in a secondary battery according to an embodiment of the present invention, and FIG. 7 is a drawing showing a current collector in a secondary battery according to an embodiment of the present invention.

[0124] Referring to FIGS. 1 to 20, directions for explaining the secondary battery (1000) are defined. A first direction (+X or -X direction) may be defined. The first direction (+X or -X direction) may mean a 'longitudinal direction of the secondary battery (1000)'. The first direction (+X or -X direction) may be a direction in which the first electrode tab (1220) and the second electrode tab (1230) are spaced apart from each other. A second direction (+Y or -Y direction) may be defined. The second direction (+Y or -Y direction) may mean a 'width direction of the secondary battery (1000)'. The second direction (+Y or -Y direction) may be a direction in which a plurality of first electrode tabs (1220) are aligned with each other. A third direction (+Z or -Z direction) may be defined. The third direction (+Z or -Z direction) may mean the 'height direction of the secondary battery (1000)'. The third direction (+Z or -Z direction) may be the direction in which the current collector (1300) and the cap assembly (1400) are coupled.

[0125]

[0126] As illustrated in FIGS. 1 and 2, a secondary battery (1000) according to one embodiment of the present invention may include a case (1100), an electrode assembly (1200), a current collector (1300), and a cap assembly (1400).

[0127] The case (1100) can form the exterior of the secondary battery (100). The case (1100) can have a space formed therein to accommodate an electrode assembly (1200), and an opening can be formed on one side of the case (1100). In the present embodiment, the shape of the case (1100) is a rectangular parallelepiped, but is not limited thereto and can be modified in various ways. The material of the case (1100) can be made of a sturdy material capable of protecting the electrode assembly (1200) accommodated therein. For example, the case (1100) can be made of a metal such as aluminum or stainless steel.

[0128] Referring to FIGS. 1 and 2, an electrolyte may be accommodated together with an electrode assembly (1200) within a case (1100). The electrolyte may be composed of a lithium salt such as LiPF6 or LiBF4 in an organic solvent such as EC, PC, DEC, EMC, or DMC. The electrolyte may be liquid, solid, or gel-like.

[0129] Referring to FIGS. 1, 2, and 3, an electrode assembly (1200) may be accommodated inside a case (1100). As illustrated in FIG. 3, the electrode assembly (1200) may include an electrode portion (1210), a plurality of first electrode tabs (1220), and a plurality of second electrode tabs (1230). Each of the plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230) may be arranged at one end of the electrode portion (1210). The plurality of first electrode tabs (1220) are aligned with the first electrode tabs (1220), and the plurality of second electrode tabs (1230) are aligned with the second electrode tabs (1230). The plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230) that are respectively aligned may be arranged so as not to overlap in the width direction (e.g., +Y direction) and the length direction (e.g., +X direction) of the electrode assembly (1200). For example, the plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230) may not overlap in the length direction (+X direction) of the electrode assembly (1200). For example, the plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230) may not overlap in the width direction (+Y direction) of the electrode assembly (1200). For example, the plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230) may be dislocated from in the length direction (+X direction) of the electrode assembly (1200). For example, a plurality of first electrode tabs (1220) and a plurality of second electrode tabs (1230) may be dislocated from each other in the width direction (+Y direction) of the electrode assembly (1200). The first electrode tabs (1220) and the second electrode tabs (1230) may be arranged at offset positions.

[0130] Referring to FIGS. 1, 2, and 3, the electrode assembly (1200) may include a plurality of third electrode tabs (1240) and a plurality of fourth electrode tabs (1250). Each of the plurality of third electrode tabs (1240) and the plurality of fourth electrode tabs (1250) may be arranged at one end of the electrode portion (1210). The plurality of third electrode tabs (1240) are aligned with each other, and the plurality of fourth electrode tabs (1250) are aligned with each other. The plurality of third electrode tabs (1240) and the plurality of fourth electrode tabs (1250) are arranged so as not to overlap in the width direction (e.g., +Y direction) and the length direction (e.g., +X direction) of the electrode assembly (1200). For example, the plurality of third electrode tabs (1240) and the plurality of fourth electrode tabs (1250) may be non-overlapping in the longitudinal direction (+X direction) of the electrode assembly (1200). For example, the plurality of third electrode tabs (1240) and the plurality of fourth electrode tabs (1250) may be non-overlapping in the width direction (+Y direction) of the electrode assembly (1200). For example, the plurality of third electrode tabs (1240) and the plurality of fourth electrode tabs (1250) may be dislocated from in the longitudinal direction (+X direction) of the electrode assembly (1200). For example, the plurality of third electrode tabs (1240) and the plurality of fourth electrode tabs (1250) may be dislocated from in the width direction (+Y direction) of the electrode assembly (1200). The third electrode tab (1240) and the fourth electrode tab (1250) may be positioned at offset positions.

[0131] Referring to FIGS. 1, 2 and 3, specifically, the electrode portion (1210) may include a plurality of first electrode members (1211), a plurality of second electrode members (1212), a plurality of third electrode members (1213), a plurality of fourth electrode members (1214), and a separator.

[0132] Referring to FIGS. 1, 2, and 3, an active material may be applied to each of a plurality of first electrode members (1211), a plurality of second electrode members (1212), a plurality of third electrode members (1213), and a plurality of fourth electrode members (1214). An active material such as a transition metal oxide may be applied to a metal plate such as aluminum on the plurality of first electrode members (1211) and the plurality of second electrode members (1212). The plurality of first electrode members (1211) and the plurality of second electrode members (1212) may have the same polarity and may be positive electrode plates. The plurality of third electrode members (1213) and the plurality of fourth electrode members (1214) may have an active material such as graphite or carbon applied to a metal plate such as copper or nickel. The plurality of third electrode members (1213) and the plurality of fourth electrode members (1214) may have the same polarity and may be negative electrode plates.

[0133] Referring to FIGS. 1, 2, and 3, a separator is positioned between a plurality of first to fourth electrode members (1211, 1212, 1213, 1214) to prevent short circuits between the plurality of first to fourth electrode members (1211, 1212, 1213, 1214). The material of the separator may be polyethylene, polypropylene, or a composite thereof.

[0134] Referring to FIGS. 1, 2, and 3, a plurality of first electrode members (1211) and a plurality of third electrode members (1213) may be arranged alternately with each other. For example, a plurality of third electrode members (1213) may be arranged between each of a plurality of first electrode members (1211), and a plurality of first electrode members (1211) may be arranged between each of a plurality of third electrode members (1213). The plurality of first electrode members (1211) and the plurality of third electrode members (1213) may be alternately stacked in the width direction (e.g., +Y direction). The electrode assembly (1200) may include a first stack portion (1205) in which the plurality of first electrode members (1211) and the plurality of third electrode members (1213) are alternately arranged. The first stack portion (1205) may be a part of the electrode assembly (1200). A plurality of first electrode members (1211) and a plurality of third electrode members (1213) can be positioned in the first stack portion (1205).

[0135] Referring to FIGS. 1, 2, and 3, a plurality of second electrode members (1212) and a plurality of fourth electrode members (1214) may be arranged alternately with each other. For example, a plurality of fourth electrode members (1214) may be arranged between each of the plurality of second electrode members (1212), and a plurality of second electrode members (1212) may be arranged between each of the plurality of fourth electrode members (1214). The plurality of second electrode members (1212) and the plurality of fourth electrode members (1214) may be alternately stacked in the width direction (e.g., +Y direction). The electrode assembly (1200) may include a second stack portion (1206) in which the plurality of second electrode members (1212) and the plurality of fourth electrode members (1214) are alternately arranged. The second stack portion (1206) may be a part of the electrode assembly (1200). A plurality of second electrode members (1212) and a plurality of fourth electrode members (1214) may be positioned in the second stack portion (1206).

[0136] Referring to FIGS. 1, 2, and 3, the first stack portion (1205) and the second stack portion (1206) may be stacked on each other. The electrode assembly (1200) may be a structure formed by stacking the first stack portion (1205) and the second stack portion (1206).

[0137] Referring to FIGS. 1, 2, and 3, each of the first stack portion (1205) and the second stack portion (1206) may form a portion of the electrode assembly (1200). For example, the first stack portion (1205) may be a portion of the electrode assembly (1200) located on one side (e.g., in the -Y direction) with respect to an imaginary plane (P4) that crosses the electrode assembly (1200) perpendicular to the width direction (e.g., in the +Y direction) of the electrode assembly (1200), and the second stack portion (1206) may be a remaining portion of the electrode assembly (1200) located on the other side (e.g., in the +Y direction) with respect to the plane (P4).

[0138] Referring to FIGS. 1, 2, and 3, the first stack portion (1205) may be formed by positioning a separator between a plurality of first electrode members (1211) and a plurality of third electrode members (1213) that are alternately arranged. The second stack portion (1206) may be formed by positioning a separator between a plurality of second electrode members (1212) and a plurality of fourth electrode members (1214) that are alternately arranged. In another embodiment of the present invention, the electrode portion may be formed by sequentially stacking a first electrode member (1211), a separator, a third electrode member (1213), a separator, a second electrode member (1212), a separator, a fourth electrode member (1214), and a separator, and then winding the stack. In another embodiment of the present invention, the electrode portion may be formed by sequentially stacking a first electrode member (1211), a separator, a third electrode member (1213), and a separator, and then winding the first stack portion (1205), and the second stack portion (1206) may be formed by sequentially stacking a second electrode member (1212), a separator, a fourth electrode member (1214), and a separator, and then winding the second stack portion (1206).

[0139] In this embodiment, the electrode assembly (1200) has one electrode portion (1210), but in other embodiments, the electrode assembly (1200) may have a plurality of electrode portions (1210). The plurality of electrode portions (1210) may be electrically connected to each other.

[0140] Referring to FIGS. 1, 2, and 3, each of the plurality of first to fourth electrode members (1211, 1212, 1213, 1214) may include an electrode tab (electrode tab, 1220, 1230, 1240, 1250) on which an active material is not applied. The electrode tab (1220, 1230, 1240, 1250) may be at least a portion of a non-conductive portion formed on each of the plurality of first to fourth electrode members (1211, 1212, 1213, 1214). In one embodiment, the electrode members (1211, 1212, 1213, 1214) and electrode tabs (1220, 1230, 1240, 1250) can be formed integrally by cutting a predetermined portion from a single metal member using a laser or the like to leave the electrode members (1211, 1212, 1213, 1214) and electrode tabs (1220, 1230, 1240, 1250). The plurality of electrode tabs (1220, 1230, 1240, 1250) can be formed in a direction toward the cap assembly (1400).

[0141] The cap assembly (1400) can seal the opening of the case (1100) in which the electrode assembly (1200) is accommodated. The cap assembly (1400) can include a cap plate (1410) and terminals (1420, 1420a). The terminals (1420, 1420a) can connect the electrode assembly (1200) to an external device.

[0142] Referring to FIGS. 1 and 2, the cap plate (1410) may be a plate shape that covers the opening of the case (1100). The cap plate (1410) may have a shape corresponding to the shape of the opening of the case (1100). The cap plate (1410) may be formed of the same material as the case (1100), and the cap plate (1410) may be fixed to the case (1100) by a method such as laser welding.

[0143] Referring to FIGS. 1 and 2, a vent hole (1411) and an electrolyte injection port (1412) may be formed in the cap plate (1410). The vent hole (1411) may be opened when the internal pressure of the case (1100) exceeds a reference value. In the present embodiment, the vent hole (1411) is formed in the cap plate (1410), but in other embodiments, the vent hole (1411) may be formed in the case (1100). An electrolyte may be injected into the interior of the case (1100) through the electrolyte injection port (1412).

[0144] Referring to FIGS. 1 and 2, terminals (1420, 1420a) may be formed to protrude from the cap plate (1410). Terminals (1420, 1420a) may be electrically connected to electrode tabs (1220, 1230, 1240, 1250) through a current collector (1300). Terminals (1420, 1420a) may be formed in the shape of a plate having a circular or rectangular shape.

[0145] Referring to FIGS. 1 and 2, a through hole may be formed in the terminal (1420, 1420a). A collector projection (1331) may be inserted into the through hole. After the collector projection (1331) is inserted into the through hole, the outer surface of the end of the collector projection (1331) and the inner surface of the end of the through hole may be welded.

[0146] An insulating material may be placed between the terminal (1420, 1420a) and the cap plate (1410). The insulating material may insulate the terminal (1420, 1420a) and the cap plate (1410) from each other.

[0147] Referring to FIG. 3, the electrode assembly (1200) may include a plurality of regions (1201, 1202, 1203, 1204). The plurality of regions (1201, 1202, 1203, 1204) may be arranged in the longitudinal direction (e.g., +X direction) of the electrode assembly (1200). Each of the plurality of regions (1201, 1202, 1203, 1204) may be a part of the electrode assembly (1200). Each of the plurality of regions (1201, 1202, 1203, 1204) may be distinguished from each other by a plurality of planes (P1, P2, P3) perpendicular to the longitudinal direction (+X direction) of the electrode assembly (1200). A plurality of planes (P1, P2, P3) may be virtual planes that are spaced apart from each other in the longitudinal direction (+X direction) of the electrode assembly (1200) to divide the electrode assembly (1200) into a plurality of regions (1201, 1202, 1203, 1204). For example, a first plane (P1) may divide the electrode assembly (1200) into a first region (1201) and a second region (1202) as boundaries. For example, a second plane (P2) may divide the electrode assembly (1200) into a second region (1202) and a third region (1203) as boundaries. For example, a third plane (P3) may divide the electrode assembly (1200) into a third region (1203) and a fourth region (1204) as boundaries.

[0148] Referring to FIG. 3, the first, second, third, and fourth electrode tabs (1220, 1230, 1240, 1250) may each be located in different areas of the electrode assembly (1200). The first electrode tab (1220) may be located in the first area (1201). The second electrode tab (1230) may be located in the second area (1202). The third electrode tab (1240) may be located in the third area (1203). The fourth electrode tab (1250) may be located in the fourth area (1204). That is, each of the first, second, third, and fourth electrode tabs (1220, 1230, 1240, 1250) can be positioned in different regions (1201, 1202, 1203, 1204) distinguished along the longitudinal direction (e.g., +X direction) of the electrode assembly (1200).

[0149] Referring to FIGS. 3 and 4, the first electrode member (1211) may include a plurality of first electrode portions (12111, 12112, 12113, 12114). The plurality of first electrode portions (12111, 12112, 12113, 12114) may be separated from each other by a plurality of planes (P1, P2, P3) spaced apart from each other in the longitudinal direction (e.g., +X direction) of the electrode assembly (1200). The first electrode member (1211) may include a first-first electrode portion (12111) located in a first region (1201). The first electrode member (1211) may include a first-second electrode portion (12112) located in a second region (1202). The first electrode member (1211) may include a 1-3 electrode portion (12113) located in a 3rd region (1203). The first electrode member (1211) may include a 1-4 electrode portion (12114) located in a 4th region (1204). The first electrode tab (1220) may be formed on the 1-1 electrode portion (12111) of the first electrode member (1211).

[0150] Referring to FIGS. 3 and 4, the second electrode member (1212) may include a plurality of second electrode portions (12121, 12122, 12123, 12124). The plurality of second electrode portions (12121, 12122, 12123, 12124) may be separated from each other by a plurality of planes (P1, P2, P3) spaced apart from each other in the longitudinal direction (e.g., +X direction) of the electrode assembly (1200). The second electrode member (1212) may include a 2-1 electrode portion (12121) located in the first region (1201). The second electrode member (1212) may include a 2-2 electrode portion (12122) located in the second region (1202). The second electrode member (1212) may include a 2-3 electrode portion (12123) located in the 3rd region (1203). The second electrode member (1212) may include a 2-4 electrode portion (12124) located in the 4th region (1204). The second electrode tab (1230) may be formed on the 2-2 electrode portion (12122) of the second electrode member (1212).

[0151] Referring to FIGS. 3 and 5, the third electrode member (1213) may include a plurality of third electrode portions (12131, 12132, 12133, 12134). The plurality of third electrode portions (12131, 12132, 12133, 12134) may be separated from each other by a plurality of planes (P1, P2, P3) spaced apart from each other in the longitudinal direction (e.g., +X direction) of the electrode assembly (1200). The third electrode member (1213) may include a 3-1 electrode portion (12131) located in the first region (1201). The third electrode member (1213) may include a 3-2 electrode portion (12132) located in the second region (1202). The third electrode member (1213) may include a third-third electrode portion (12133) located in the third region (1203). The third electrode member (1213) may include a third-fourth electrode portion (12134) located in the fourth region (1204). The third electrode tab (1240) may be formed on the third-third electrode portion (12133) of the third electrode member (1213).

[0152] Referring to FIGS. 3 and 5, the fourth electrode member (1214) may include a plurality of fourth electrode portions (12141, 12142, 12143, 12144). The plurality of fourth electrode portions (12141, 12142, 12143, 12144) may be separated from each other by a plurality of planes (P1, P2, P3) spaced apart from each other in the longitudinal direction (e.g., +X direction) of the electrode assembly (1200). The fourth electrode member (1214) may include a 4-1 electrode portion (12141) located in the first region (1201). The fourth electrode member (1214) may include a 4-2 electrode portion (12142) located in the second region (1202). The fourth electrode member (1214) may include a 4-3 electrode portion (12143) located in the third region (1203). The fourth electrode member (1214) may include a 4-4 electrode portion (12144) located in the fourth region (1204). The fourth electrode tab (1250) may be formed on the 4-4 electrode portion (12144) of the fourth electrode member (1214).

[0153] Referring to FIGS. 3, 4, and 5, a plurality of first electrode members (1211) and a plurality of third electrode members (1213) may be alternately stacked with a separator interposed therebetween. A stack of a plurality of first electrode members (1211) and a plurality of third electrode members (1213) may form one half of an electrode portion (1210) (e.g., a first stack portion (1205)).

[0154] Referring to FIGS. 3, 4, and 5, a plurality of second electrode members (1212) and a plurality of fourth electrode members (1214) may be alternately stacked with a separator interposed therebetween. The stack of a plurality of second electrode members (1212) and a plurality of fourth electrode members (1214) may form the remaining half of the electrode portion (1210) (e.g., the second stack portion (1206)).

[0155] Referring to FIG. 3, a first stack portion (1205) including a plurality of first electrode members (1211) and a plurality of third electrode members (1213) and a second stack portion (1206) including a plurality of second electrode members (1212) and a plurality of fourth electrode members (1214) are connected in the width direction (e.g., +Y direction) of the electrode portion (1210). When forming the electrode assembly (1200), after stacking the plurality of first electrode members (1211) and the plurality of third electrode members (1213), the plurality of second electrode members (1212) and the plurality of fourth electrode members (1214) can be stacked.

[0156] Referring to FIG. 3, a plurality of first electrode tabs (1220) may overlap each other in a first region (1201) of the electrode assembly (1200). A plurality of second electrode tabs (1230) may overlap each other in a second region (1202) of the electrode assembly (1200). That is, a plurality of first electrode tabs (1220) may be grouped in the first region (1201), and a plurality of second electrode tabs (1230) may be grouped in the second region (1202). The plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230) that are grouped may be positioned spaced apart from each other in different regions (1201, 1202) of the electrode assembly (1200). The plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230) that are each grouped can be spaced apart in the width direction (e.g., +Y direction) and length direction (e.g., +X direction) of the electrode assembly (1200).

[0157] Referring to FIG. 6, the current collector (1300) may include a first current collector (1310), a second current collector (1320), and a connecting portion (1330).

[0158] Referring to FIG. 6, the current collector (1300) may have a rectangular shape extending in the longitudinal direction of the electrode assembly (1200) (e.g., the +X direction of FIG. 3). The current collector (1300) may include a first current collector (1310), a connecting portion (1330), and a second current collector (1320) that are sequentially arranged in the longitudinal direction of the rectangle. The connecting portion (1330) may be arranged between the first current collector (1310) and the second current collector (1320). The first current collector (1310), the second current collector (1320), and the connecting portion (1330) may be formed as an integral body. The first collector (1310) may be a part of the collector (1300) located on one side of the connecting portion (1330), and the second collector (1320) may be a part of the collector (1300) located on the other side of the connecting portion (1330).

[0159] Referring to FIGS. 2 and 6, the first current collector (1310) may be welded with a plurality of first electrode tabs (1220). The plurality of first electrode tabs (1220) may be bent and welded onto the first current collector (1310). The second current collector (1320) is welded with a plurality of second electrode tabs (1230). The plurality of second electrode tabs (1230) may be bent and welded onto the second current collector (1320). The current collector (1300) may include a lower surface (1300a) facing the electrode assembly (1200). The lower surface (1300a) may be referred to as a “first surface.” The current collector (1300) may include an upper surface (1310a, 1320a) to which the plurality of first and second electrode tabs (1220, 1230) are welded. The upper surface (1310a, 1320a) may be referred to as a “second surface.” The upper surface (1310a, 1320a) may be a surface opposite to the lower surface (1300a) that faces the electrode assembly (1200). The upper surface (1310a, 1320a) may face the terminal (1420, 1420a). The upper surface (1310a, 1320a) may include a first welding surface (1310a) on which a plurality of first electrode tabs (1220) are welded. The first welding surface (1310a) may be a top surface of the first current collector (1310). The upper surface (1310a, 1320a) may include a second welding surface (1320a) on which a plurality of second electrode tabs (1230) are welded. The second welding surface (1320a) may be the upper surface of the second collector (1320).

[0160] Referring to FIGS. 2 and 6, a connecting portion (1330) may be disposed between a first collector portion (1310) and a second collector portion (1320). Each of the first collector portion (1310) and the second collector portion (1320) may be connected to both sides of the connecting portion (1330). Since the first collector portion (1310) and the second collector portion (1320) are separated by the connecting portion (1330), a plurality of first electrode tabs (1220) and a plurality of second electrode tabs (1230) may not interfere with each other when welded.

[0161] Referring to FIGS. 2 and 6, two current collectors (1300) may be provided, and the material of the current collectors (1300) may be the same as the material of at least one of the first to fourth electrode tabs (1220, 1230, 1240, 1250). That is, the current collector (1300) may be formed of aluminum, or may be formed of copper or nickel. The description of the welding of the first and second electrode tabs (1220, 1230) and the current collector (1300) described above may be equally applied to the description of the welding of the third and fourth electrode tabs (1240, 1250) and the current collector (1300). For example, the third electrode tab (1240) can be welded to the first welding surface (1310a) of the first collector (1310), and the fourth electrode tab (1250) can be welded to the second welding surface (1320a) of the second collector (1320).

[0162] Referring to FIGS. 2 and 6, the current collector (1300) may include a current collector protrusion (1331). The current collector protrusion (1330) may be electrically connected to an electrode terminal. The current collector protrusion (1331) may be formed to protrude from the connection portion (1330). The current collector protrusion (1331) may be positioned between the first current collector portion (1310) and the second current collector portion (1320). The material of the current collector protrusion (1331) may be the same as or different from the material of the connection portion (1330). For example, both the connection portion (1330) and the current collector protrusion (1331) may be formed of aluminum. Alternatively, the connection portion (1330) may be formed of copper, and the current collector protrusion (1331) may be formed of aluminum. When the material of the collector protrusion (1331) and the material of the connecting portion (1330) are the same, the connecting portion (1330) and the collector protrusion (1331) can be formed as one piece.

[0163] Referring to FIGS. 2 and 6, the current collector (1300) may have a thickness of 0.5 to 3.0 mm. The width of the current collector (1300) may be 0.5 to 0.8 times the width of the electrode assembly (1200). The current collector (1300) is positioned on the electrode assembly (1200), and electrode tabs (1220, 1230, 1240, 1250) are positioned on the upper surface (1310a, 1320a) of the current collector (1300), and the electrode tabs (1220, 1230, 1240, 1250) may be welded to the upper surface (1310a, 1320a) of the current collector (1300). In the past, since the current collector was placed on the top of the electrode tab and then welding was performed, it was necessary to melt the lower portion of the current collector that was in contact with the electrode tab, making it impossible to increase the thickness of the current collector. In the secondary battery (1000) according to one embodiment of the present invention, since the electrode tabs (1220, 1230, 1240, 1250) are welded on the upper surface (1310a, 1320a) of the current collector (1300), there is no need to melt the lower portion of the current collector (1300) during the welding process, so the thickness of the current collector (1300) can be increased, and thus the durability of the secondary battery can be improved. In addition, since welding was performed after placing the current collector on top of the electrode tab in the past, high output of the laser was required to reach the electrode tab under the current collector, but in the secondary battery (1000) according to one embodiment of the present invention, welding is possible with a small output because the electrode tabs (1220, 1230, 1240, 1250) are welded on the upper surface (1310a, 1320a) of the current collector (1300).

[0164] Referring to FIGS. 2 and 6, a secondary battery (1000) according to one embodiment of the present invention welds electrode tabs (1220, 1230, 1240, 1250) on the upper surface (1310a, 1320a) of a current collector (1300) that does not face the electrode assembly (1200), thereby preventing sparks or foreign substances generated during the welding process from penetrating into the electrode assembly (1200), thereby reducing damage to the separator.

[0165] Referring to FIGS. 2 and 7, a protective layer (1340) may be disposed on the lower portion of the current collector (1300). The protective layer (1340) may be disposed on the lower surface (1300a) of the current collector (1300). The protective layer (1340) may be an insulating plate or an insulating film. The protective layer (1340) may protect the current collector (1300), electrode tabs (1220, 1230, 1240, 1250), and the electrode assembly (1200). For example, electrode tabs (1220, 1230, 1240, 1250) and a current collector (1300) are provided on one side of the protective layer (1340), and an electrode part (e.g., electrode part (1210) of FIG. 3) of an electrode assembly (1200) is provided on the other side of the protective layer (1340), thereby insulating between the electrode part (1210) and the current collector (1300), thereby preventing electrical interference between the electrode tabs (1220, 1230, 1240, 1250), the current collector (1300), and the electrode part (1210).

[0166]

[0167] FIG. 8 is a flowchart showing a method for manufacturing a secondary battery according to an embodiment of the present invention, FIG. 9 is a diagram showing a state in which a plurality of first electrode tabs and a plurality of second electrode tabs are each grouped in a secondary battery according to an embodiment of the present invention, FIG. 10 is a diagram showing a state in which a plurality of first electrode tabs and a plurality of second electrode tabs are each firstly welded in a secondary battery according to an embodiment of the present invention, FIG. 11 is a diagram showing a state in which a current collector is arranged between a plurality of first electrode tabs and a plurality of second electrode tabs in a secondary battery according to an embodiment of the present invention, FIG. 12 is a diagram showing a state in which a current collector and first and second electrode tabs are welded in a secondary battery according to an embodiment of the present invention, and FIG. 13 is a diagram showing a state in which a cap assembly is coupled to an electrode assembly in a secondary battery according to an embodiment of the present invention.

[0168] The assembly method of the first electrode tab (1220), the second electrode tab (1230), the current collector (1300), and the terminal (1420) described with reference to FIGS. 8 to 13 can be equally applied to the assembly method of the third electrode tab (1240), the fourth electrode tab (1250), the current collector (1300), and the terminal (1420a) as illustrated in FIG. 2.

[0169] Referring to FIGS. 8 and 9, a method for manufacturing a secondary battery according to an embodiment of the present invention may include a step (S1100) of preparing an electrode assembly. The electrode assembly (1200) may include an electrode portion (1210), a plurality of first electrode tabs (1220), and a plurality of second electrode tabs (1230).

[0170] Referring to FIG. 9, a plurality of first electrode tabs (1220) may be arranged in one area (e.g., the first area (1201)) of the electrode assembly (1200). When a plurality of electrode members (e.g., the plurality of first electrode members (1211) of FIG. 3) are stacked to form a first stack portion (1205), the plurality of first electrode tabs (1220) may be positioned to overlap each other in the first electrode tab area (1201). That is, the plurality of first electrode tabs (1220) may be grouped in the first area (1201).

[0171] Referring to FIG. 9, a plurality of second electrode tabs (1230) may be arranged in one area (e.g., the second area (1202)) of the electrode assembly (1200). When a plurality of electrode members (e.g., the plurality of second electrode members (1212) of FIG. 3) are stacked to form a second stack portion (1206), the plurality of second electrode tabs (1230) may be positioned to overlap each other in the second electrode member area (1202). That is, the plurality of second electrode tabs (1230) may be grouped in the second area (1202).

[0172] Referring to FIGS. 4, 5, and 9, only one electrode tab (1220, 1230, 1240, 1250) is formed on one electrode member (1211, 1212, 1213, 1214). However, in the secondary battery (1000) according to one embodiment of the present invention, the positions at which the electrode tabs (1220, 1230, 1240, 1250) are formed on each electrode member (1211, 1212, 1213, 1214) are different, so that after the electrode members (1211, 1212, 1213, 1214) are stacked, two groups of electrode tabs having different positions on each of the positive and negative electrodes can be formed. In another embodiment, two or more electrode tabs having different positions on the same electrode may be formed.

[0173] Referring to FIG. 9, a plurality of grouped first electrode tabs (1220) may be positioned in a first region (1201) of a first electrode tab stack portion (1205). A plurality of grouped second electrode tabs (1230) may be positioned in a second region (1202) of a second stack portion (1206). The plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230) may be spaced apart from each other in the longitudinal direction (e.g., +X direction) of the electrode assembly (1200). A gap (G) may be formed between the plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230). The electrode assembly (1200) may include a bridge portion (1207) formed between the plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230). The bridge portion (1207) may be a portion of the electrode assembly (1200) positioned between the first electrode tab (1220) and the second electrode tab (1230) spaced apart in the longitudinal direction (e.g., +X direction). The bridge portion (1207) may provide a position at which a current collector protrusion (e.g., a current collector protrusion (1331) of FIG. 6) of a current collector (e.g., a current collector (1300) of FIG. 6) protrudes. The connecting portion (e.g., a connecting portion (1330) of FIG. 6) of the current collector (e.g., a current collector (1300) of FIG. 6) may be positioned to correspond to the bridge portion (1207). The current collector protrusion (e.g., a current collector protrusion (1331) of FIG. 6) of the current collector (1300) may protrude toward a terminal (e.g., a terminal (1420) of FIG. 2) at a position corresponding to the bridge portion (1207).

[0174] Referring to FIGS. 8 and 10, a method for manufacturing a secondary battery according to an embodiment of the present invention may include a primary welding step (S1200). A plurality of grouped first electrode tabs (1220) may be first welded to each other, and a plurality of grouped second electrode tabs (1230) may be first welded to each other, respectively.

[0175] Referring to FIG. 10, a plurality of first electrode tabs (1220) and a plurality of second electrode tabs (1230) may be electrode tabs of the same polarity, and in order to stably weld a large number of first electrode tabs and second electrode tabs (1220, 1230), a plurality of first electrode tabs may be first welded together and a plurality of second electrode tabs may be first welded together, and then a second welding may be performed on a current collector (e.g., a current collector (1300) of FIG. 11). A plurality of third electrode tabs (e.g., the third electrode tab (1240) of FIG. 3) and a plurality of fourth electrode tabs (e.g., the fourth electrode tab (1250) of FIG. 3) may be electrode tabs of the same polarity, and similarly to the case of the plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230), the plurality of third electrode tabs may be first welded together and the plurality of fourth electrode tabs may be first welded together, and then second welded on the current collector (1300). The plurality of electrode tabs (1220, 1230, 1240, 1250) overlapping at each position may be first welded by ultrasonic welding, laser welding, or the like, respectively, to facilitate the movement of current.

[0176] Referring to FIG. 10, the electrode assembly (1200) may include a first electrode tab assembly (1221). The first electrode tab assembly (1221) may be a structure in which a plurality of first electrode tabs (1220) are welded to each other. That is, the first electrode tab assembly (1221) may be an assembly in which a plurality of first electrode tabs (1220) that overlap each other are first welded.

[0177] Referring to FIG. 10, the first electrode tab assembly (1221) may include a 1-1 assembly portion (1221a). The 1-1 assembly portion (1221a) may be a portion in which a plurality of first electrode tabs (1220) are welded in an overlapping state. The first electrode tab assembly (1221) may include a first assembly welding portion (1221d). The first assembly welding portion (1221d) may be formed on the 1-1 assembly portion (1221a). The first electrode tab assembly (1221) may include a 1-2 assembly portion (1221b) and a 1-3 assembly portion (1221c). The 1-2 assembly part (1221b) may be a part that extends from the 1-1 assembly part (1221a) in one direction (e.g., +Y direction), and the 1-3 assembly part (1221c) may be a part that extends from the 1-1 assembly part (1221a) in a direction opposite to the 1-2 assembly (1221b) (e.g., -Y direction). The 1-3 assembly part (1221c) may extend in a direction opposite to the direction toward the outside of the electrode assembly (1200), that is, the direction toward the second stack part (1206) based on the width direction of the electrode assembly (1200).

[0178] Referring to FIG. 10, the electrode assembly (1200) may include a second electrode tab assembly (1231). The second electrode tab assembly (1231) may be a structure in which a plurality of second electrode tabs (1230) are welded to each other. That is, the second electrode tab assembly (1231) may be an assembly in which a plurality of second electrode tabs (1230) that overlap each other are first welded.

[0179] Referring to FIG. 10, the second electrode tab assembly (1231) may include a 2-1 assembly portion (1231a). The 2-1 assembly portion (1231a) may be a portion in which a plurality of second electrode tabs (1230) are welded in an overlapping state. The second electrode tab assembly (1231) may include a second assembly welding portion (1231d). The second assembly welding portion (1231d) may be formed on the 2-1 assembly portion (1231a). The second electrode tab assembly (1231) may include a 2-2 assembly portion (1231b) and a 2-3 assembly portion (1231c). The 2-2 assembly part (1231b) may be a part that extends from the 2-1 assembly part (1231a) in one direction (e.g., -Y direction), and the 2-3 assembly part (1231c) may be a part that extends from the 2-1 assembly part (1231a) in a direction opposite to the 2-2 assembly (1231b) (e.g., +Y direction). The 2-3 assembly part (1231c) may extend in a direction toward the outside of the electrode assembly (1200), that is, in a direction opposite to the direction toward the first stack part (1205) based on the width direction of the electrode assembly (1200).

[0180] Referring to FIGS. 8 and 11, a method for manufacturing a secondary battery according to an embodiment of the present invention may include a step (S1300) of placing a current collector (1300). The current collector (1300) may be placed between a plurality of first electrode tabs (1220) and a plurality of second electrode tabs (1230) that are first welded. In order to connect the plurality of electrode tabs (1220, 1230) to the current collector (1300), in the present embodiment, electrode tabs (1220, 1230) of the same polarity are divided into two electrode tab assemblies (1221, 1231) and welded to the current collector (1300). For example, the first electrode tab assembly (1221) can be welded to the first collector portion of the current collector (1300) (e.g., the first collector portion (1310) of FIG. 12), and the second electrode tab assembly (1231) can be welded to the second collector portion of the current collector (1300) (e.g., the second collector portion (1320) of FIG. 12).

[0181]

[0182] Referring to FIG. 11, the current collector (1300) can be arranged to cover at least a portion of the first electrode tab assembly (1221) and at least a portion of the second electrode tab assembly (1231). The current collector (1300) can overlap with at least a portion of the first electrode tab assembly (1221) and at least a portion of the second electrode tab assembly (1231) in a third direction (e.g., +Z direction). For example, the current collector (1300) can be arranged to cover the first-second assembly portion (1221b) and the second-second assembly portion (1231b). The first-second assembly portion (1221b) can be positioned between the electrode portion (1210) of the electrode assembly (1200) and the current collector (1300). The 2-2 assembly part (1231b) may be positioned between the electrode portion (1210) of the electrode assembly (1200) and the current collector (1300). The current collector protrusion (1331) may protrude between the 1-2 assembly part (1221b) and the 2-2 assembly part (1231b). The current collector (1300) may be placed in a space formed between the first electrode tab assembly (1221) and the second electrode tab assembly (1231). To facilitate placement of the current collector (1300), each of the first electrode tab assembly (1221) and the second electrode tab assembly (1231) may be temporarily bent toward the outer side of the electrode assembly (1200).

[0183] Referring to FIGS. 8, 11, and 12, a method for manufacturing a secondary battery according to an embodiment of the present invention may include a step (S1400) of bending a first electrode tab (1220) and a second electrode tab (1230) toward the upper surface (1310a, 1320a) of a current collector (1300), respectively. The plurality of first electrode tabs (1220) may be bent toward the upper surface (1310a) of the first current collector (1310) of the current collector (1300), and the plurality of second electrode tabs (1230) may be bent toward the upper surface (1320a) of the second current collector (1320) of the current collector (1300). The plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230) may be bent in opposite directions.

[0184] Referring to FIGS. 8, 11, and 12, the first electrode tab assembly (1221) can be bent onto the first welding surface (1310a) of the first collector (1310). The 1-1 assembly portion (1221a) can be bent onto the first welding surface (1310a). The 1-1 assembly portion (1221a) can be bent toward the second stack portion (e.g., the second stack portion (1206) of FIG. 3). At this time, since the 1-2 assembly part (1221b) is positioned between the lower surface (1300a) of the current collector (1300) and the electrode portion (1210) of the electrode assembly (1200), the bending of the 1-1 assembly part (1221a) can be supported by the 1-2 assembly part (1221b) pressed by the current collector (1300). The 1-3 assembly part (1221c) can provide structural stability of the first electrode tab assembly (1221) by extending away from the current collector (1300) from the 1-1 assembly part (1221a). For example, the 1-3 assembly part (1221c) has a structure that spreads widely in the width direction (e.g., -Y direction) of the 1-1 assembly part (1221a) during the bending and welding process of the 1-1 assembly part (1221a), thereby dispersing the stress applied to the 1-1 assembly part (1221a) in the width direction.

[0185] Referring to FIGS. 8, 11, and 12, the second electrode tab assembly (1231) can be bent onto the second welding surface (1320a) of the second current collector (1320). The 2-1 assembly portion (1231a) can be bent onto the second welding surface (1320a). The 2-1 assembly portion (1231a) can be bent toward the first stack portion (e.g., the first stack portion (1205) of FIG. 3). At this time, since the 2-2 assembly part (1231b) is positioned between the lower surface (1300a) of the current collector (1300) and the electrode part (1210) of the electrode assembly (1200), the bending of the 2-1 assembly part (1231a) can be supported by the 2-2 assembly part (1231b) pressed by the current collector (1300). The 2-3 assembly part (1231c) can provide structural stability of the second electrode tab assembly (1231) by extending away from the current collector (1300) from the 2-1 assembly part (1231a). For example, the 2-3 assembly part (1231c) has a structure that spreads widely in the width direction (e.g., +Y direction) of the 2-1 assembly part (1231a) during the bending and welding process of the 2-1 assembly part (1231a), thereby dispersing the stress applied to the 2-1 assembly part (1231a) in the width direction.

[0186] Meanwhile, the sum of the areas of the first-first assembly part (1221a) and the second-first assembly part (1231a) that are bent and placed on the collector (1300) may have a predetermined ratio with respect to the area of ​​the upper surface of the collector plate (1300). For example, the sum of the areas of the first-first assembly part (1221a) and the second-first assembly part (1231a) may be 1 / 4 to 1 / 6 of the area of ​​the upper surface of the collector plate (1300).

[0187] If the area of ​​the electrode tab placed on the current collector is narrow, it may be difficult for the electrode tab to sufficiently contact the current collector, and the current flow may not be smooth. Therefore, it is desirable that the area of ​​the electrode tab placed on the top surface of the current collector be at least 1 / 6 of the area of ​​the current collector.

[0188] Additionally, if multiple electrode tabs are placed on the current collector, the amount of electrode tab melting increases during the secondary welding process, which can lead to uneven weld bead heights. This can cause problems during cap plate assembly. Therefore, it is recommended that the area of ​​the electrode tabs be less than one-quarter of the current collector area.

[0189] Referring to FIGS. 11 and 12, the first-second assembly portion (1221b) may be positioned between the first current collector welding portion (1221e) and the electrode assembly (1200). The second-second assembly portion (1231b) may be positioned between the second current collector welding portion (1231e) and the electrode assembly (1200). The first current collector (1310) may be positioned between the first current collector welding portion (1221e) and the first-second assembly portion (1221b). The second current collector (1320) may be positioned between the second current collector welding portion (1231e) and the second-second assembly portion (1231b). Due to the above-described structure, foreign substances generated when welding the 1-1 and 2-1 assembly parts (1221a, 1231a) to the current collector (1300) may be blocked by the 1-2 and 2-2 assembly parts (1221b, 1231b) and may not reach the electrode assembly (1200).

[0190] Referring to FIGS. 8 and 12, a method for manufacturing a secondary battery according to an embodiment of the present invention may include a step (S1500) of welding a current collector (1300) and electrode tabs (1220, 1230). A plurality of first electrode tabs (1220) may be welded to a first current collector (1310), and a plurality of second electrode tabs (1230) may be welded to a second current collector (1320). The welding may be performed downward from a position above the plurality of first electrode tabs (1220) and the plurality of second electrode tabs (1230). The welding may be performed using a method such as ultrasonic welding or laser welding.

[0191] During welding, welding may be performed from a plurality of first electrode tabs (1220) toward the first collector (1310) of the current collector (1300), and welding may be performed from a plurality of second electrode tabs (1230) toward the second collector (1320) of the current collector (1300).

[0192] Referring to FIG. 12, the first electrode tab assembly (1221) may be welded to the first current collector (1310), and the second electrode tab assembly (1231) may be welded to the second current collector (1320). The first electrode tab assembly (1221) may include a first current collector welding portion (1221e). The first current collector welding portion (1221e) may be formed on the 1-1 assembly portion (1221a). The first current collector welding portion (1221e) may be formed by welding the first electrode tab assembly (1221) and the current collector (1300). The second electrode tab assembly (1231) may include a second current collector welding portion (1231e). The second current collector welding portion (1231e) may be formed on the 2-1 assembly portion (1231a). The second current collector welding portion (1231e) can be formed by welding the second electrode tab assembly (1231) and the current collector (1300).

[0193] Referring to FIGS. 11 and 12, after first welding a plurality of electrode tabs (1220, 1230) to form first and second electrode tab assemblies (1221, 1231), the first and second electrode tab assemblies (1221, 1231) can be secondarily welded to a current collector (1300). Accordingly, the first and second electrode tab assemblies (1221, 1231) can include first and second assembly welding portions (1221d, 1231d) and first and second current collector welding portions (1221e, 1231e). By welding the plurality of electrode tabs (1220, 1230) in the above-described manner, all of the plurality of electrode tabs (1220, 1230) can be stably welded to the current collector (1300) so that no electrode tab among the plurality of electrode tabs (1220, 1230) is unwelded. The first welding direction and the second welding direction of the first and second electrode tab assemblies (1221, 1231) may be different. For example, the first and second assembly welding portions (1221d, 1231d) can be formed in a first direction (e.g., +X direction), and the first and second current collector welding portions (1221e, 1231e) can be formed in a second direction (e.g., +Y direction). As described above, since the first welding direction and the second welding direction are different, damage to the first and second electrode tab assemblies (1221, 1231) that may occur due to repeated welding at the same location can be prevented. The first and second assembly welding portions (1221d, 1231d) may extend across the first and second electrode tab assemblies (1221, 1231) in the longitudinal direction (e.g., +X direction). The first and second current collector welding portions (1221e, 1231e) may be formed in multiple numbers spaced apart from each other in the longitudinal direction (e.g., +X direction) of the first and second electrode tab assemblies (1221, 1231).In a secondary battery (1000) according to one embodiment of the present invention, an assembly welding portion (1221d, 1231d) formed by primary welding and a current collector welding portion (1221e, 1231e) formed by secondary welding can be distinguished from each other. For example, the assembly welding portion (1221d, 1231d) formed by primary welding and the current collector welding portion (1221e, 1231e) formed by secondary welding can be formed in an intersecting direction. The assembly welding portion (1221d, 1231d) formed by primary welding and the current collector welding portion (1221e, 1231e) formed by secondary welding can also be formed in different regions of the electrode tab assembly (1221, 1231) without directionality.

[0194] Meanwhile, the area of ​​the secondary welding region formed on the first and second electrode tabs may have a predetermined ratio with respect to the area of ​​the first and second electrode tabs (1221a, 1231a) bent and placed on the current collector. For example, the area of ​​the secondary welding region formed on the first and second electrode tabs may be 1 / 5 to 1 / 7 of the area of ​​the first and second electrode tabs (1221a, 1231a) bent and placed on the current collector, respectively.

[0195] A narrow secondary welding area can increase electrical resistance, leading to increased heat generation in the first and second electrode tabs. Furthermore, the weld joint strength can be weakened, potentially leading to separation of the electrode tab and current collector. Therefore, the secondary welding area should preferably be at least 1 / 7th of the current collector area.

[0196] A large secondary welding area can reduce electrical resistance and improve current flow between the electrode tab and the external circuit. However, if the secondary welding area is too large, the increased welding time can offset the improved current flow, potentially reducing manufacturing efficiency. Furthermore, a large secondary welding area can cause heat to be transferred to the outside of the current collector during the welding process, potentially damaging the separator. Therefore, it is recommended that the secondary welding area be no larger than 1 / 5 of the current collector area.

[0197] In the present embodiment, the plurality of electrode tabs are first welded to the first electrode tabs (1220) and to the second electrode tabs (1230), and then welded to the current collector (1300). However, in another embodiment, the plurality of electrode tabs (1220, 1230) may be welded directly onto the current collector (1300) by bending them without first welding them. For example, in the secondary battery according to another embodiment of the present invention, each of the plurality of electrode tabs (1220, 1230) may be welded to the current collector (1300). That is, in the secondary battery according to another embodiment of the present invention, each of the plurality of electrode tabs (1220, 1230) may be bent to the surface of the current collector (1300) to overlap each other, and the plurality of electrode tabs (1220, 1230) that are overlapped may be welded to the current collector (1300).

[0198] Referring to FIG. 12, the current collector protrusion (1331) may be positioned between the first electrode tab assembly (1221) and the second electrode tab assembly (1231). The current collector protrusion (1331) may be positioned between the 1-1 assembly portion (1221a) and the 2-1 assembly portion (1231a). The current collector protrusion (1331) may be positioned between the first current collector welding portion (1221e) and the second current collector welding portion (1231e).

[0199] Meanwhile, after the secondary welding is completed, a cover member (1360) may be placed on the welded portion on the current collector (1300). The cover member (1360) may cover at least a portion of the electrode assembly (1200). The cover member (1360) may include an insulating material. The connecting portion (1330) and the current collector protrusion (1331) may be exposed on the outside of the cover member (1360). The terminals (1420, 1420a) may be coupled to the current collector protrusion (1331) exposed on the outside of the cover member (1360). The width (w1) of the cover member (1360) may be 1 to 1.2 times the width (w2) of the first and second electrode tabs. By forming the width (w1) of the cover member (1360) to be 1 to 1.2 times the width (w2) of the first and second electrode tabs, the entire welding portion can be covered while minimizing the area fixed by the cover member (1360).

[0200] Referring to FIGS. 2 and 13, an electrode assembly (1200) to which a current collector (1300) is welded can be accommodated within a case (1100), and a cap assembly (1400) can seal an opening of the case (1100). At this time, after a current collector protrusion (1331) is inserted into a through-hole of a terminal (1420) of the cap assembly (1400), an outer surface of an end of the current collector protrusion (1331) and an inner surface of an end of the through-hole can be welded.

[0201] Fig. 14 is a block diagram illustrating a method for manufacturing a secondary battery according to another embodiment of the present invention. Figs. 15 to 20 are diagrams illustrating a method for manufacturing a secondary battery according to another embodiment of the present invention. The description of the method for manufacturing a secondary battery according to one embodiment of the present invention described with reference to Figs. 1 to 13 can also be equally applied to the method for manufacturing a secondary battery according to another embodiment of the present invention described with reference to Figs. 14 to 20.

[0202] Referring to FIGS. 14 to 20, the method for manufacturing a secondary battery may include a step (S2100) of preparing an electrode assembly (1200). The method for manufacturing a secondary battery may include a step (S2200) of welding a plurality of first electrode tabs (1220) and a step (S2300) of welding a plurality of second electrode tabs (1230). The method for manufacturing a secondary battery may include a step (S2300) of arranging an insulating member (1350). The method for manufacturing a secondary battery may include a step (S2400) of arranging a current collector (2300) between a plurality of first electrode tabs (1220) and a plurality of second electrode tabs (1230). The method for manufacturing a secondary battery may include a step (S2500) of bending a plurality of first electrode tabs (1220) toward a first collector (2310) and a step (S2500) of bending a plurality of second electrode tabs (1230) toward a second collector (2320). The method for manufacturing a secondary battery may include a step (S2600) of welding a plurality of first electrode tabs (1220) and a first collector (2310) and welding a plurality of second electrode tabs (1230) and a second collector (2320). The method for manufacturing a secondary battery may include a step (S2700) of arranging a cover member (1360).

[0203]

[0204] Referring to FIGS. 9, 10, and 14, a method for manufacturing a secondary battery may include a step (S2100) of preparing an electrode assembly (1200) and a step (S2200) of welding a plurality of first electrode tabs (1220) and welding a plurality of second electrode tabs (1230) together. The description of each step (S2100, S2200) may be identically applied to the description with reference to FIGS. 9 and 10. For example, a plurality of first electrode tabs (1220) may be welded to each other to form a first electrode tab assembly (1221) including a first assembly welding portion (1221d), and a plurality of second electrode tabs (1230) may be welded to each other to form a second electrode tab assembly (1231) including a second assembly welding portion (1231d).

[0205] Referring to FIGS. 15 and 16, an insulating member (1350) may be disposed. The insulating member (1350) may be disposed to cover at least a portion of the electrode assembly (1200). At least a portion of the insulating member (1350) may be bent. The electrode portion (1210) may include a first electrode surface (1210a) and a second electrode surface (1210b). The first and second electrode tab assemblies (1221, 1231) may be disposed on the first electrode surface (1210a). The second electrode surface (1210b) may extend in a direction intersecting the first electrode surface (1210a). The insulating member (1350) may include a first insulating portion (1351) and a second insulating portion (1352). The first insulating portion (1351) may cover the first electrode surface (1210a). The second insulating portion (1352) may cover the second electrode surface (1210b). The insulating member (1350) may include a first insulating member (1350a) extending toward the first electrode tab assembly (1221) and a second insulating member (1350b) extending toward the second electrode tab assembly (1231). The insulating member (1350) may cover at least a portion of the first and second electrode tab assemblies (1221, 1231). For example, the first insulating member (1350a) may cover at least a portion of the first-second assembly portion (1221b), and the second insulating member (1350b) may cover at least a portion of the second-second assembly portion (1231b). The first electrode tab assembly (1221) may include a first assembly insulating portion (1221b1) covered by the insulating member (1350). The second electrode tab assembly (1231) may include a second assembly insulating portion (1231b1) covered by an insulating member (1350).

[0206] Referring to FIGS. 17 and 18, a current collector (2300) may be placed on an electrode assembly (1200), and first and second electrode tab assemblies (1221, 1231) may be welded to the current collector (2300). The structure in which the first and second electrode tab assemblies (1221, 1231) are welded to the current collector (2300) may be identically applied to the description of the welding structure described with reference to FIGS. 11 and 12.

[0207] Referring to FIGS. 17 and 18, a current collector (2300) may be disposed on an electrode assembly (1200). The current collector (2300) may extend across each of the first electrode tab assembly (1221) and the second electrode tab assembly (1231). The current collector (2300) may include a first current collector (2310) welded to the first electrode tab assembly (1221) and a second current collector (2320) welded to the second electrode tab assembly (1231). The current collector (2300) may include a connecting portion (2330) positioned between the first current collector (2310) and the second current collector (2320). The current collector (2300) may include a current collector edge (2311). A current collector edge (2311) may be disposed on one side of the first current collector (2310). The current collector edge (2311) may be disposed between an edge (1200d) of the electrode assembly (1200) and the first and second electrode tab assemblies (1221, 1231). The current collector (2300) may include a current collector protrusion (2331). The current collector protrusion (2331) may protrude from the current collector edge (2311). The current collector protrusion (2331) may be positioned between the edge (1200d) of the electrode assembly (1200) and the first and second electrode tab assemblies (1221, 1231).

[0208] Referring to FIGS. 17 and 18, the first electrode tab assembly (1221) can be bent toward the first collector (2310), and the first electrode tab assembly (1221) can be welded to the first welding surface (2310a) of the first collector (2310). The second electrode tab assembly (1231) can be bent toward the second collector (2320), and the second electrode tab assembly (1231) can be welded to the second welding surface (2320a) of the second collector (2320). The collector (2300) can include an upper surface (2300b) including the first welding surface (2310a) and the second welding surface (2320a). The first and second electrode tab assemblies (1221, 1231) can be welded to the upper surface (2300b) of the current collector (2300).

[0209] Referring to FIGS. 17 and 18, the ends of the first and second electrode tab assemblies (1221, 1231) may be spaced apart from one side (2300c) of the current collector (2300) adjacent thereto. For example, after the first and second electrode tab assemblies (1221, 1231) are welded to the current collector (2300), the ends of the first-first and second-first assembly portions (1221a, 1231a) may be spaced apart from one side (2300c) of the current collector (2300) adjacent thereto. The end of the first-first assembly portion (1221a) may be spaced apart from one side (2300c) of the current collector (2300) adjacent thereto by a first distance (d5). The end of the 2-1 assembly part (1231a) can be spaced apart from one side (2300c) of the adjacent collector (2300) by a second gap (d6).

[0210] Referring to FIGS. 17 and 18, insulating members (1350a, 1350b) may be disposed between the electrode portion (1210) and the current collector (2300). For example, at least a portion of the first insulating member (1350a) may be disposed between the electrode portion (1210) and the first current collector (2310). For example, at least a portion of the second insulating member (1350b) may be disposed between the electrode portion (1200) and the second current collector (2320). Since the insulating members (1350a, 1350b) are disposed between the electrode portion (1210) and the current collector (2300), the flow of foreign substances generated when the first and second electrode tab assemblies (1221, 1231) are welded to the current collector (2300) into the electrode portion (1210) may be blocked. Additionally, due to the arrangement of the insulating member (1350a, 1350b), electrical insulation can be achieved between the electrode tab assembly (1221, 1231) and the current collector (2300) welded assembly and the electrode portion (1210).

[0211] Referring to FIGS. 19 and 20, a cover member (1360) may be disposed. The cover member (1360) may cover an electrode tab assembly (e.g., electrode tab assemblies (1221, 1231) of FIG. 18) and a current collector (e.g., current collector (2300) of FIG. 18). The cover member (1360) may cover at least a portion of the electrode assembly (1200). The cover member (1360) may include an insulating material. A current collecting edge (2311) and a current collecting protrusion (2331) may be exposed on the outside of the cover member (1360). A terminal (e.g., a terminal (1420, 1420a) of FIG. 1) may be coupled with a current collecting protrusion (2331) exposed on the outside of the cover member (1360).

[0212] Referring to FIGS. 19 and 20, the cover member (1360) can cover the electrode portion (1210), the insulating member (1350), the current collector (2300), and the electrode tab assembly (1221). The cover member (1360) can be laminated with each of the electrode portion (1210), the insulating member (1350), the current collector (2300), and the electrode tab assembly (1221). For example, the electrode portion (1210), the insulating member (1350), the current collector (2300), the electrode tab assembly (1221), and the cover member (1360) can be sequentially laminated along one direction (e.g., the +Z direction). At least a portion of the electrode tab assembly (1221) (e.g., the first-second assembly portion (1221b)) can be disposed between the electrode portion (1210) and the insulating member (1350). On an imaginary line (L1) extending in one direction (e.g., +Z direction), an electrode portion (1210), a 1-2 assembly portion (1221b), an insulating member (1350), a current collector (2300), a 1-1 assembly portion (1221a), and a cover member (1360) can be sequentially stacked. Due to the above-described structure, since the 1-1 assembly portion (1221a) is bent while the 1-2 assembly portion (1221b) is pressed toward the electrode portion (1210) by the insulating member (1350) and the current collector (2300), bending of the 1-1 assembly portion (1221a) can be facilitated. Due to the structure described above, when welding the 1-1 assembly part (1221a) to the current collector (2300), since the insulating member (1350) and the 1-2 assembly part (1221b) are positioned between the current collector (2300) and the electrode part (1210), foreign substances generated by welding can be prevented from flowing toward the electrode part (1210).

[0213]

[0214] In the secondary battery according to the comparative example, since the current collector is welded on top of the electrode tab, the current collector must be thin to transfer heat to the electrode tab located below, which leads to reduced durability. However, in the secondary battery according to one embodiment of the present invention, the thickness of the current collector can be secured by bending and welding a plurality of electrode tabs on the current collector, and the electrode tabs can be welded to the current collector more efficiently.

[0215] In addition, the present invention can stably weld electrode tabs without any unwelded portions by dividing a plurality of electrode tabs having the same polarity into two groups and welding them.

[0216]

[0217] Above, one embodiment of the present invention has been described, but a person having ordinary skill in the art will be able to modify and change the present invention in various ways by adding, changing, deleting or adding components, etc., within the scope that does not depart from the spirit of the present invention described in the claims, and this will also be considered to be included within the scope of the rights of the present invention.

Claims

An electrode assembly comprising an electrode portion, a plurality of first electrode tabs and a plurality of second electrode tabs formed at one end of the electrode portion; and A current collector is disposed on the upper portion of the electrode portion and includes a first current collector welded to the plurality of first electrode tabs and a second current collector welded to the plurality of second electrode tabs; A secondary battery, wherein the plurality of first electrode tabs are bent in one direction toward the first current collector of the current collector, and the plurality of second electrode tabs are bent in the opposite direction to the first electrode tabs toward the second current collector of the current collector. In the first paragraph, The above-mentioned collector includes a first surface facing the electrode portion and a second surface opposite to the first surface, and at least a portion of the first surface is positioned between the first electrode tab and the second electrode tab, A secondary battery, wherein the first electrode tab and the second electrode tab are positioned at offset positions with the current collector interposed therebetween, and are each bent toward the second surface and welded to the second surface. In the first paragraph, The above electrode part It comprises a plurality of first electrode members having first electrode tabs formed at first positions and a plurality of second electrode members having second electrode tabs formed at second positions. A secondary battery, wherein the first electrode member and the second electrode member have the same polarity. In the first paragraph, A secondary battery, wherein the plurality of first electrode tabs and the plurality of second electrode tabs are spaced apart in the width direction (y direction) and the length direction (x direction) of the electrode assembly. In the first paragraph, A secondary battery, wherein the plurality of first electrode tabs are pre-welded to each other, and the plurality of second electrode tabs are pre-welded to each other. In the first paragraph, A secondary battery, wherein the first current collector and the second current collector are arranged in the longitudinal direction of the electrode assembly. In the first paragraph, The above-mentioned entire house, A secondary battery further comprising a connecting portion disposed between the first current collector and the second current collector and having a current collector projection. In the first paragraph, The above-mentioned entire house, A secondary battery further comprising a current collecting edge disposed on one side of the first current collecting portion and having a current collecting projection. In the first paragraph, A secondary battery having a protective layer disposed on the lower portion of the above-mentioned collector. In the first paragraph, A secondary battery having a thickness of the entire body of the battery of 0.5 to 3.0 mm. In the second paragraph, A secondary battery further comprising a cover member covering the first and second electrode tabs each welded to the above-described collector. In the first paragraph, A secondary battery, wherein the above-mentioned current collector protrusion is formed of the same material as the first current collector and the second current collector. In the first paragraph, A secondary battery, wherein the above-mentioned current collector protrusion is formed of a different material from the first current collector and the second current collector. A plurality of first electrode members each including a first electrode tab; A plurality of second electrode members each including a second electrode tab; A plurality of third electrode members each including a third electrode tab; A plurality of fourth electrode members each including a fourth electrode tab; An electrode assembly comprising a first stack portion formed by stacking a plurality of first electrode members and a plurality of third electrode members, the first stack portion having a length in a first direction and a width in a second direction perpendicular to the first direction, the plurality of second electrode members and the plurality of fourth electrode members being stacked, and the second stack portion stacked in the second direction with the first stack portion; A first electrode tab assembly formed in the first stack portion by combining the first electrode tabs of each of the plurality of first electrode members and positioned in a first region among the plurality of regions of the electrode assembly divided in the first direction; and A secondary battery comprising a second electrode tab assembly formed in the second stack portion by combining the second electrode tabs of each of the plurality of second electrode members, and located in a second region different from the first region among the plurality of regions of the electrode assembly divided in the first direction. In the first paragraph, A case in which the electrode assembly is received, once opened; A secondary battery further comprising a cap assembly coupled to one end of the case and having an electrode terminal electrically connected to the collector. In Article 15, The above electrode terminal is provided with a through hole, A secondary battery, wherein the above-mentioned current collector protrusion is inserted into the above-mentioned through-hole of the above-mentioned electrode terminal. A preparatory step in which an electrode assembly is prepared, comprising an electrode part, a plurality of first electrode tabs formed at one end of the electrode part, and a plurality of second electrode tabs; A first welding step in which the plurality of first electrode tabs are welded to each other, and the plurality of second electrode tabs are welded to each other; A current collector arrangement step in which a current collector is arranged between the plurality of first electrode tabs and the plurality of second electrode tabs that are first welded; A bending step in which the plurality of first electrode tabs are bent to the upper surface of the first current collector of the current collector, and the plurality of second electrode tabs are bent to the upper surface of the second current collector of the current collector; and A method for manufacturing a secondary battery, comprising a second welding step in which the plurality of first electrode tabs are welded to the first current collector, and the plurality of second electrode tabs are welded to the second current collector, respectively. In Article 17, A method for manufacturing a secondary battery, wherein the plurality of first electrode tabs and the plurality of second electrode tabs have the same polarity. In Article 17, A method for manufacturing a secondary battery, wherein the first current collector and the second current collector are arranged in the longitudinal direction of the electrode assembly. In Article 17, A method for manufacturing a secondary battery, wherein a protective layer is disposed on the lower portion of the above-mentioned collector. In Article 17, A method for manufacturing a secondary battery, wherein the current collector has a current collector projection formed of a different material from the first current collector and the second current collector between the first current collector and the second current collector. In Article 17, A method for manufacturing a secondary battery, wherein the current collector has a current collector projection formed of the same material as the first current collector and the second current collector between the first current collector and the second current collector.

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