Method for manufacturing secondary battery, secondary battery, battery module including the secondary battery, battery pack, and transportation vehicle

Abstract

The present invention relates to a method for manufacturing a secondary battery, a secondary battery, a battery module including the secondary battery, a battery pack, and a transportation vehicle. The secondary battery according to the present invention can include an electrode assembly and a current collector plate. The electrode assembly can include an electrode unit and a plurality of first foil tabs and a plurality of second foil tabs formed at one end portion of the electrode unit. The current collector plate can include a first current collecting portion welded to the plurality of first foil tabs and a second current collecting portion welded to the plurality of second foil tabs. The plurality of first foil tabs can be bent in a direction toward the first current collecting portion of the current collector plate, and the plurality of second foil tabs can be bent in a direction opposite to the direction of the first foil tabs, toward the second current collecting portion of the current collector plate. The present invention can prevent an un-welded portion from occurring in some of the foil tabs when a large number of foil tabs are welded to the current collector plate.

Description

Technical Field

[0001] This disclosure relates to a method for manufacturing a secondary battery, a secondary battery, a battery module including the secondary battery, a battery pack, and a vehicle, and more specifically, to a method for manufacturing a secondary battery, a secondary battery, a battery module including the secondary battery, a battery pack, and a vehicle, wherein the secondary battery includes an electrode assembly and a current collector and is configured such that the current collector includes a connection portion and a first current collector portion and a second current collector portion extending perpendicularly from a first side and a second side of the connection portion, respectively, wherein a plurality of first foil tabs are bent in a direction toward the first current collector portion, and a plurality of second foil tabs are bent in a direction opposite to the bending direction of the first foil tabs and toward the second current collector portion. Background Technology

[0002] Recently, with the rapid increase in demand for portable electronic devices and the more active development of electric vehicles, energy storage batteries, robots, satellites, etc., high-performance rechargeable and rechargeable batteries have been extensively studied.

[0003] Secondary batteries can be classified according to the shape of their casing into can-type secondary batteries, in which the electrode components are embedded in a metal can, and bag-type secondary batteries, in which the electrode components are embedded in a pouch formed of aluminum laminates. Can-type secondary batteries can be further classified according to the shape of the metal can into cylindrical secondary batteries and prismatic secondary batteries.

[0004] In a secondary battery, the foil tabs and current collectors of the electrode assembly are joined together by welding. When welding the foil tabs and current collectors, the foil tabs are bent in the bending direction to increase the contact area between the foil tabs and the current collectors, and the current collectors are placed on the upper portion of the foil tabs and then welded to the upper portion of the foil tabs.

[0005] However, in this case, there is a risk of damaging the separator during the welding process of the current collector and the foil tabs placed below it. Additionally, as the capacity of secondary batteries increases, the number of foil tabs requiring simultaneous welding increases, and therefore, there is a risk that foil tabs spaced further from the current collector may not be welded correctly.

[0006] Therefore, there is a need to develop a secondary battery that eliminates the risk of damaging the separator and enables the stable welding of a large number of foil tabs to the current collector. Summary of the Invention Technical issues

[0007] This disclosure aims to provide a secondary battery and a method for manufacturing the secondary battery, which can prevent the electrode assembly from being affected when the foil tabs and current collectors are welded to each other.

[0008] This disclosure aims to provide a secondary battery and a method for manufacturing the secondary battery, wherein a large number of foil pieces can be reliably welded to the current collector when foil pieces and current collectors are welded to each other. Technical solution

[0009] A secondary battery according to one aspect of this disclosure may include an electrode assembly and a current collector. The electrode assembly may include an electrode portion and a plurality of first foil tabs and a plurality of second foil tabs formed at one end of the electrode portion. The current collector may be disposed in the upper portion of the electrode portion and includes a first current collector portion, a second current collector portion, and a connecting portion. The first current collector portion may be soldered to the plurality of first foil tabs. The second current collector portion may be soldered to the plurality of second foil tabs. The connecting portion may be connected to the first current collector portion in its lower portion on a first side and to the second current collector portion in its upper portion on a second side. The first current collector portion and the second current collector portion extend perpendicularly from a first side and a second side of the connecting portion, respectively. The plurality of first foil tabs may be bent in a direction toward the first current collector portion, and the plurality of second foil tabs may be bent in a direction opposite to the direction of the first foil tabs and toward the second current collector portion.

[0010] According to one aspect of this disclosure, a plurality of first foil tabs and a plurality of second foil tabs may be soldered onto a first current collector and a second current collector, respectively.

[0011] According to one aspect of this disclosure, the electrode portion may include a plurality of first electrode plates and a plurality of second electrode plates, wherein a first foil tab is formed on the first electrode plate at a first position, and a second foil tab is formed on the second electrode plate at a second position. The first electrode plates and the second electrode plates may have the same polarity.

[0012] According to one aspect of this disclosure, a plurality of first foil tabs and a plurality of second foil tabs may be spaced apart from each other in the width direction (y direction) and the longitudinal direction (x direction) of the electrode assembly.

[0013] According to one aspect of this disclosure, in a first foil patch, a plurality of first foil patches may be pre-welded to each other, and in a second foil patch, a plurality of second foil patches may be pre-welded to each other.

[0014] According to one aspect of this disclosure, an insulator may be disposed below the lower surface of the current collector.

[0015] According to one aspect of this disclosure, the current collector may be disposed in a region at one end of the electrode portion where the plurality of first foil tabs and the plurality of second foil tabs are not formed.

[0016] According to one aspect of this disclosure, the current collector may be disposed between a plurality of first foil tabs and a plurality of second foil tabs at one end of the electrode portion.

[0017] According to one aspect of this disclosure, the flow collection protrusion may be formed of the same material as the connecting portion.

[0018] According to one aspect of this disclosure, the flow collection protrusion may be formed of a material different from that of the connecting portion.

[0019] According to one aspect of this disclosure, the thickness of the current collector can be in the range of 0.5 mm to 3.0 mm.

[0020] A method for manufacturing a secondary battery according to one aspect of the present disclosure may include: a preparation operation of preparing an electrode assembly including an electrode portion and a plurality of first foil tabs and a plurality of second foil tabs formed at one end of the electrode portion; a current collector placement operation of placing a current collector in a region at one end of the electrode portion where the plurality of first foil tabs and the plurality of second foil tabs are not formed; a bending operation of bending the plurality of first foil tabs in a direction toward an upper surface of a first current collecting portion of the current collector, and bending the plurality of second foil tabs in a direction opposite to the bending direction of the first foil tabs and toward an upper surface of a second current collecting portion of the current collector; and a welding operation of welding the plurality of bent first foil tabs and the plurality of bent second foil tabs to the current collector.

[0021] According to one aspect of this disclosure, the method may further include a preliminary welding operation after the preparation operation, wherein a plurality of first foil pieces are pre-welded in the first foil pieces, and a plurality of second foil pieces are pre-welded in the second foil pieces.

[0022] According to one aspect of this disclosure, the current collector may include a connecting portion having a current collecting protrusion. A first current collecting portion may be vertically connected to a lower portion on a first side of the connecting portion, and a second current collecting portion may be vertically connected to an upper portion on a second side of the connecting portion.

[0023] According to one aspect of this disclosure, in the current collector, the first current collector portion and the second current collector portion may be made of the same material as the first foil tab and the second foil tab.

[0024] According to one aspect of this disclosure, an insulator may be disposed below the lower surface of the current collector.

[0025] According to one aspect of this disclosure, in the welding operation, in the first current collector section, welding can be performed from a plurality of first foil tabs toward the first current collector section, and in the second current collector section, welding can be performed from a plurality of second foil tabs toward the second current collector section.

[0026] According to one aspect of this disclosure, the battery module may include a secondary battery.

[0027] According to one aspect of this disclosure, a battery pack may include a battery module.

[0028] According to one aspect of this disclosure, a means of transport may include a battery pack. Beneficial effects

[0029] In the secondary battery and the method of manufacturing the secondary battery according to the embodiments of the present disclosure, when the foil sheet and the current collector are welded together, damage to the separator can be prevented.

[0030] In the secondary battery and the method of manufacturing the secondary battery according to the embodiments of the present disclosure, when a large number of foil sheets and current collectors are welded together, it is possible to prevent unwelded portions from appearing in some foil sheets. Attached Figure Description

[0031] Figure 1 This is a view illustrating a secondary battery according to an embodiment of the present disclosure.

[0032] Figure 2 This is a view illustrating a secondary battery according to an embodiment of the present disclosure.

[0033] Figure 3 This is a perspective view of an electrode assembly in a secondary battery according to an embodiment of the present disclosure, wherein a plurality of first foil tabs and a plurality of second foil tabs are formed on the electrode portion.

[0034] Figure 4a and Figure 4b This is a view illustrating the first electrode plate and the second electrode plate in a secondary battery according to an embodiment of the present disclosure.

[0035] Figure 5a and Figure 5b This is a view illustrating the third and fourth electrode plates in a secondary battery according to an embodiment of the present disclosure.

[0036] Figure 6 This is a view illustrating the current collector in a secondary battery according to an embodiment of the present disclosure.

[0037] Figure 7a and Figure 7b This is a view illustrating the current collector in a secondary battery according to an embodiment of the present disclosure.

[0038] Figure 8a and Figure 8b This is a view illustrating a current collector including an insulator in a secondary battery according to an embodiment of the present disclosure.

[0039] Figure 9 This is a view illustrating a current collector disposed at one end of an electrode portion in a secondary battery according to an embodiment of the present disclosure.

[0040] Figure 10This is a view illustrating a current collector welded to a first foil tab and a second foil tab in a secondary battery according to an embodiment of the present disclosure.

[0041] Figure 11 This is a cross-sectional view illustrating the current collector and the first foil tab welded together in a secondary battery according to an embodiment of the present disclosure.

[0042] Figure 12 This is a flowchart illustrating a method for manufacturing a secondary battery according to an embodiment of the present disclosure.

[0043] Figure 13 This is a view illustrating a plurality of first foil tabs and a plurality of second foil tabs respectively grouped in a secondary battery according to an embodiment of the present disclosure.

[0044] Figure 14a and Figure 14b This is a view illustrating a current collector in a secondary battery according to an embodiment of the present disclosure, which is disposed at one end of the electrode portion and welded to a plurality of first foil tabs and a plurality of second foil tabs.

[0045] Figure 15a , Figure 15b and Figure 15c This is a view illustrating a current collector in a secondary battery according to an embodiment of the present disclosure, disposed between and welded to a plurality of first foil contacts and a plurality of second foil contacts.

[0046] Figure 16 This is a view illustrating the welding direction during the welding of the current collector and the first foil tab in a secondary battery according to an embodiment of the present disclosure.

[0047] Figure 17 This is a view illustrating a current collector welded to a first foil tab and a second foil tab in a secondary battery according to an embodiment of the present disclosure.

[0048] Figure 18 This is a view illustrating a covering element disposed on the portion of the current collector and the first foil tab welded together in a secondary battery according to an embodiment of the present disclosure.

[0049] Figure 19 This is a view illustrating a cover assembly connected to an electrode assembly in a secondary battery according to an embodiment of the present disclosure. Detailed Implementation

[0050] Because this disclosure can be modified in various forms and has various implementations, specific implementations will be illustrated in the accompanying drawings and described in detail with reference to the drawings. However, this is not intended to limit this disclosure to a particular mode of practice, and it should be understood that all variations, equivalents, and substitutions that do not depart from the spirit and technical scope of this disclosure are included in this disclosure.

[0051] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. In this disclosure, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. It will also be understood that the terms “comprising,” “having,” etc., as used in this specification, are intended to indicate the presence of stated features, integers, steps, operations, elements, components, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0052] In the following, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that throughout the drawings, the same reference numerals refer to the same elements. To avoid unnecessarily obscuring the spirit of the disclosure, details of well-known configurations and functions may be omitted. For the same reason, some elements in the drawings are enlarged, omitted, or depicted schematically.

[0053] Figure 1 This is a view illustrating a secondary battery according to an embodiment of the present disclosure. Figure 2 This is a view illustrating a secondary battery according to an embodiment of the present disclosure. Figure 3 This is a perspective view of an electrode assembly in a secondary battery according to an embodiment of the present disclosure, wherein a plurality of first foil tabs and a plurality of second foil tabs are formed on the electrode portion.

[0054] Figure 4a and Figure 4b This is a view illustrating the first electrode plate and the second electrode plate in a secondary battery according to an embodiment of the present disclosure. Figure 5a and Figure 5b This is a view illustrating the third and fourth electrode plates in a secondary battery according to an embodiment of the present disclosure. Figure 6 This is a view illustrating the current collector in a secondary battery according to an embodiment of the present disclosure.

[0055] like Figure 1 and Figure 2 As shown, the secondary battery 1000 according to an embodiment of the present disclosure includes a housing 1100, an electrode assembly 1200, a current collector 1300, and a cover assembly 1400.

[0056] The housing 1100 forms the external shape of the secondary battery 100. The housing 1100 may define a space capable of housing the electrode assembly 1200 therein, and may have an opening on one surface of the housing 1100. In this embodiment, the housing 1100 has a cuboid shape, but is not limited thereto, and can be modified in various ways. The housing 1100 may be made of a rigid material capable of protecting the electrode assembly 1200 housed therein. For example, the housing 1100 may be made of a metal such as aluminum or stainless steel.

[0057] The electrolyte can be housed together with the electrode assembly 1200 in a cartridge 1100. The electrolyte may include lithium salts such as LiPF6 or LiBF4 in organic solvents such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), or dimethyl carbonate (DMC). The electrolyte may be a liquid, solid, or gel phase.

[0058] The electrode assembly 1200 is housed in the housing 1100. For example... Figure 3 As shown, the electrode assembly 1200 includes an electrode portion 1210, a plurality of first foil tabs 1220, and a plurality of second foil tabs 1230. The plurality of first foil tabs 1220 and the plurality of second foil tabs 1230 are disposed at one end of the electrode portion 1210. In the first foil tabs 1220, the plurality of first foil tabs 1220 are grouped and aligned with each other, and in the second foil tabs 1230, the plurality of second foil tabs 1230 are grouped and aligned with each other. The plurality of first foil tabs 1220 and the plurality of second foil tabs 1230, respectively aligned with each other, are arranged so as not to overlap in the width direction (y-direction) and the longitudinal direction (x-direction) of the electrode assembly 1200.

[0059] Specifically, the electrode portion 1210 includes a plurality of first electrode plates 1211, a plurality of second electrode plates 1212, a plurality of third electrode plates 1213, a plurality of fourth electrode plates 1214, and a separator.

[0060] An active material can be applied to multiple first electrode plates 1211, multiple second electrode plates 1212, multiple third electrode plates 1213, and multiple fourth electrode plates 1214. The multiple first electrode plates 1211 and multiple second electrode plates 1212 can each be formed by applying an active material, such as a transition metal oxide, to a metal plate, such as an aluminum plate. The multiple first electrode plates 1211 and multiple second electrode plates 1212 can have the same polarity and can be positive electrode plates. The multiple third electrode plates 1213 and multiple fourth electrode plates 1214 can each be formed by applying an active material, such as graphite or carbon, to a metal plate, such as a copper plate or a nickel plate. The multiple third electrode plates 1213 and multiple fourth electrode plates 1214 can have the same polarity and can be negative electrode plates.

[0061] The separator is positioned between the plurality of first electrode plates to fourth electrode plates 1211, 1212, 1213 and 1214 to prevent short circuits between the plurality of first electrode plates to fourth electrode plates 1211, 1212, 1213 and 1214. The separator may be made of polyethylene, polypropylene, or composite materials thereof.

[0062] Electrode portion 1210 can be formed by positioning spacers between sequentially arranged first electrode plates 1211 and third electrode plates 1213, and between sequentially arranged second electrode plates 1212 and fourth electrode plates 1214. In other words, in one embodiment, electrode portion 1210 can be formed such that one side of electrode portion 1210 is formed by stacking the first electrode plate 1211, spacers, third electrode plate 1213, and spacers in the listed order dozens to hundreds of times, and the other side of electrode portion 1210 is formed by stacking the second electrode plate 1212, spacers, fourth electrode plate 1214, and spacers in the listed order dozens to hundreds of times. In another embodiment, electrode portion 1210 can be formed by sequentially stacking the first electrode plate 1211, spacers, third electrode plate 1213, spacers, second electrode plate 1212, spacers, fourth electrode plate 1214, and spacers in the listed order, and then winding the stacked structure.

[0063] Although the electrode assembly 1200 is shown as including a single electrode portion 1210 in this embodiment, in another embodiment, the electrode assembly 1200 may include multiple electrode portions 1210. The multiple electrode portions 1210 may be electrically connected to each other.

[0064] At one end of a plurality of first to fourth electrode plates 1211, 1212, 1213, and 1214, a first foil patch 1220, a second foil patch 1230, a third foil patch 1240, and a fourth foil patch 1250, respectively, are formed without any active material applied. In an embodiment, each of the electrode plates 1211, 1212, 1213, and 1214 and the corresponding foil patch 1220, 1230, 1240, or 1250 can be integrally formed by cutting a predetermined portion of a single metal plate using a laser or the like, such that the electrode plates 1211, 1212, 1213, or 1214 and the foil patches 1220, 1230, 1240, or 1250 are retained. The plurality of foil patches 1220, 1230, 1240, and 1250 can be formed in a direction toward the cover assembly 1400.

[0065] Each first foil patch in the first foil patch 1220 can be formed at a first position on the corresponding first electrode plate 1211, and each second foil patch in the second foil patch 1230 can be formed at a second position on the corresponding second electrode plate 1212 (see...). Figure 4a and Figure 4b Similarly, each third foil patch in the third foil patch 1240 can be formed at a third position on the corresponding third electrode plate 1213, and each fourth foil patch in the fourth foil patch 1250 can be formed at a fourth position on the corresponding fourth electrode plate 1214 (see...). Figure 5a and Figure 5b ).

[0066] Multiple first electrode plates 1211 and multiple third electrode plates 1213 can be stacked alternately, wherein corresponding spacers are inserted between adjacent electrode plates. The stack including multiple first electrode plates 1211 and multiple third electrode plates 1213 forms half of the electrode portion 1210.

[0067] Multiple second electrode plates 1212 and multiple fourth electrode plates 1214 can be stacked alternately, wherein corresponding spacers are inserted between adjacent electrode plates. The stack including multiple second electrode plates 1212 and multiple fourth electrode plates 1214 forms the remaining half of the electrode portion 1210.

[0068] A stack comprising a plurality of first electrode plates 1211 and a plurality of third electrode plates 1213 is connected to a stack comprising a plurality of second electrode plates 1212 and a plurality of fourth electrode plates 1214 along the width direction of the electrode portion 1210. During the formation of the electrode assembly 1200, the plurality of first electrode plates 1211 and the plurality of third electrode plates 1213 may be stacked before the plurality of second electrode plates 1212 and the plurality of fourth electrode plates 1214 are stacked.

[0069] When multiple first to fourth electrode plates 1211, 1212, 1213, and 1214 are stacked, multiple first foil tabs 1220 overlap each other at a first position, and multiple second foil tabs 1230 overlap each other at a second position. In other words, among the multiple first foil tabs 1220 and multiple second foil tabs 1230 having the same polarity, the multiple first foil tabs 1220 are grouped at the first position, and the multiple second foil tabs 1230 are grouped at the second position. The first and second positions are spaced apart from each other on the electrode plates. The grouped multiple first foil tabs 1220 and the grouped multiple second foil tabs 1230 may be spaced apart in the width direction (y-direction) and the longitudinal direction (x-direction) of the electrode assembly 1200.

[0070] To achieve reliable welding of a large number of foil tabs, foil tabs of the same polarity are divided into two groups spaced apart from each other, and each group is welded to the current collector. That is, although a single foil tab is formed on each electrode plate, by changing the position of the foil tabs formed on the respective electrode plates, two groups of foil tabs with the same polarity but different positions are formed after stacking the electrode plates. In another embodiment, two or more foil tabs can be formed at different positions on the same polarity side.

[0071] When multiple first to fourth electrode plates 1211, 1212, 1213, and 1214 are stacked, multiple third foil tabs 1240 overlap each other at a third position, and multiple fourth foil tabs 1250 overlap each other at a fourth position. In other words, the multiple third foil tabs 1240 are grouped at the third position, and the multiple fourth foil tabs 1250 are grouped at the fourth position. The third and fourth positions are spaced apart from each other on the electrode plates. The grouped multiple third foil tabs 1240 and the grouped multiple fourth foil tabs 1250 may be spaced apart in the width direction (y-direction) and the longitudinal direction (x-direction) of the electrode assembly 1200.

[0072] The plurality of third foil tabs 1240 and the plurality of fourth foil tabs 1250 may be foil tabs with the same polarity.

[0073] Multiple foil pieces 1220, 1230, 1240 and 1250 overlapping at corresponding positions can be connected to the corresponding current collector by ultrasonic welding, laser welding or other means to facilitate current flow.

[0074] like Figure 6 As shown, the current collector 1300 may include a first current collector portion 1310, a second current collector portion 1320, a connecting portion 1330, and a current collector protrusion 1331.

[0075] The first foil patch 1220 can be soldered to the first current collector 1310. The second foil patch 1230 can be soldered to the second current collector 1320.

[0076] The structure of the current collector will be described later in this paper.

[0077] The cover assembly 1400 seals the opening of the housing 1100 that contains the electrode assembly 1200. The cover assembly 1400 includes a cover plate 1410 and terminals 1420 and 1420a.

[0078] The cover 1410 may have a plate shape that covers the opening of the box 1100. The cover 1410 may have a shape that corresponds to the shape of the opening of the box 1100. The cover 1410 may be formed of the same material as the box 1100 and may be fixed to the box 1100 by a method such as laser welding.

[0079] The cover plate 1410 may have a vent 1411 and an electrolyte injection port 1412. The vent 1411 opens when the internal pressure of the housing 1100 exceeds a reference value. In this embodiment, the vent 1411 is formed in the cover plate 1410; however, in other embodiments, the vent 1411 may be formed in the housing 1100. Electrolyte can be injected into the housing 1100 through the electrolyte injection port 1412.

[0080] Terminals 1420 and 1420a may be formed to protrude from cover plate 1410. Terminals 1420 and 1420a are electrically connected to foil tabs 1220 and 1220a respectively via current collector 1300. Terminals 1420 and 1420a may each have a circular plate shape or a rectangular plate shape.

[0081] A through hole may be formed in each of terminals 1420 and 1420a. Each current collector protrusion 1331 is inserted into the corresponding through hole. After the current collector protrusion 1331 is inserted into the through hole, the outer peripheral surface of the end of the current collector protrusion 1331 and the inner peripheral surface of the end of the through hole may be welded.

[0082] Insulators 1430 and 1430a may be positioned between terminals 1420 and 1420a and cover plate 1410, respectively. Insulators 1430 and 1430a electrically insulate terminals 1420 and 1420a from cover plate 1410.

[0083] Figure 7a and Figure 7b This is a view illustrating the current collector in a secondary battery according to an embodiment of the present disclosure. Figure 8a and Figure 8b This is a view illustrating a current collector including an insulator in a secondary battery according to an embodiment of the present disclosure.

[0084] Figure 9 This is a view illustrating a current collector disposed at one end of an electrode portion in a secondary battery according to an embodiment of the present disclosure. Figure 10 This is a view illustrating a current collector welded to a first foil tab and a second foil tab in a secondary battery according to an embodiment of the present disclosure. Figure 11 This is a cross-sectional view illustrating the current collector and the first foil tab welded together in a secondary battery according to an embodiment of the present disclosure.

[0085] like Figure 7a As shown, the current collector 1300 may include a first current collector portion 1310, a second current collector portion 1320, and a connecting portion 1330.

[0086] The current collector 1300 has a "Z" shape. The current collector 1300 is configured such that a first current collector portion 1310 and a second current collector portion 1320 are respectively connected to opposite sides of the connecting portion 1330 and extend from the connecting portion 1330, which serves as the center. The first current collector portion 1310 can be connected in a direction perpendicular to the lower portion of the first side of the connecting portion 1330 (x-direction), and the second current collector portion 1320 can be connected in a direction perpendicular to the upper portion of the second side of the connecting portion 1330 (x-direction). The first current collector portion 1310 and the second current collector portion 1320 can each be connected to the connecting portion 1330 at one side and can extend in opposite directions along the longitudinal direction (x-direction) of the electrode assembly 1200.

[0087] In other words, the first collector portion 1310 and the second collector portion 1320 are arranged to be offset from each other in the longitudinal direction with the connecting portion 1330 as the center. Due to the offset arrangement of the first collector portion 1310 and the second collector portion 1320, the shape formed by connecting the first collector portion 1310, the second collector portion 1320, and the connecting portion 1330 can be a stepped shape or a "Z" shape. The longitudinal center line C1 of the first collector portion 1310 and the longitudinal center line C2 of the second collector portion 1320 can be parallel to each other.

[0088] The first current collector 1310, the second current collector 1320, and the connecting portion 1330 are integrally formed from the same material, and the first current collector 1310 and the second current collector 1320 are electrically connected.

[0089] An insulator 1340 may be disposed below the current collector 1300 (see below). Figure 8a and Figure 8b Insulator 1340 may be an insulating plate or an insulating film. Insulator 1340 may further protect foil tabs 1220 and 1230 and electrode portion 1210.

[0090] In the current collector 1300, the width of the first current collector portion 1310 and the width of the second current collector portion 1320 can be 0.3 to 0.5 times the width of the electrode assembly 1200.

[0091] like Figure 9As shown, the current collector 1300 may be disposed on a portion of one end of the electrode portion 1210 where the plurality of first foil tabs 1220 and the plurality of second foil tabs 1230 are not formed. Because the plurality of first foil tabs 1220 and the plurality of second foil tabs 1230 are spaced apart in the width and longitudinal directions of the electrode assembly 1200, an area where no foil tabs are formed is defined on one side of the plurality of first foil tabs 1220 and the plurality of second foil tabs 1230. The current collector 1300 is configured such that the first current collector portion 1310 and the second current collector portion 1320 are respectively located on the portion where no foil tabs are formed.

[0092] The first current collector 1310 is soldered to a plurality of first foil tabs 1220. The plurality of first foil tabs 1220 can be bent onto and soldered to the first current collector 1310. The second current collector 1320 is soldered to a plurality of second foil tabs 1230. The plurality of second foil tabs 1230 can be bent onto and soldered to the second current collector 1320. That is, the plurality of first foil tabs 1220 and the plurality of second foil tabs 1230 are bent and soldered in opposite directions.

[0093] Welding is performed on multiple first foil tabs 1220 and multiple second foil tabs 1230. Methods such as ultrasonic welding and laser welding can be used for welding. During welding, in the first current collection section 1310 of the current collector 1300, welding can proceed from the multiple first foil tabs 1220 toward the first current collection section 1310, and in the second current collection section 1320 of the current collector 1300, welding can proceed from the multiple second foil tabs 1230 toward the second current collection section 1320.

[0094] like Figure 10 As shown, because the first current collector 1310 and the second current collector 1320 are offset in the longitudinal direction (x direction) and the width direction (y direction) of the electrode assembly 1200 via the connecting portion 1330, the plurality of first foil tabs 1220 and the plurality of second foil tabs 1230 will not interfere with each other when they are respectively soldered to the first current collector 1310 and the second current collector 1320.

[0095] Two current collectors 1300 can be provided, and the material of each current collector 1300 can be the same as that of the first foil patch 1220 and the second foil patch 1230 or the third foil patch 1240 and the fourth foil patch 1250. In other words, the current collector 1300 can be formed of aluminum, or it can be formed of copper or nickel.

[0096] A current collector protrusion 1331 is provided on the connecting portion 1330. The current collector protrusion 1330 is electrically connected to the electrode terminal. The material of the current collector protrusion 1231 may be the same as or different from the material of the connecting portion 1330. For example, both the connecting portion 1330 and the current collector protrusion 1231 may be formed of aluminum. Alternatively, the connecting portion 1330 may be formed of copper, and the current collector protrusion 1231 may be formed of aluminum. When the material of the current collector protrusion 1231 is the same as the material of the connecting portion 1330, the connecting portion 1330 and the current collector protrusion 1331 may be integrally formed.

[0097] The current collector 1300 can have a thickness ranging from 0.5 mm to 3.0 mm. In this disclosure, the current collector 1300 is located in the area of ​​the electrode portion where the foil tabs are not formed, and the foil tabs 1220 and 1230 are bent onto the current collector 1300 before being soldered from the upper side of the foil tabs 1220 and 1230. Therefore, the thickness of the current collector 1300 can be increased. Consequently, the durability of the secondary battery can also be improved.

[0098] Multiple fine grooves or multiple fine protrusions can be formed on the upper surface of the current collector 1300. These fine grooves and fine protrusions can melt first during welding, thereby enabling the current collector 1300 to fuse more firmly with the foil tabs 1220 and 1230.

[0099] In this disclosure, the foil patch is positioned on the current collector 1300 and soldered from the upper side of the foil patch (see [reference]). Figure 11 Therefore, there is no risk of damaging the separators located in the electrode section.

[0100] Furthermore, in related technologies, welding is performed after the current collector is placed on the foil tab, thus requiring high laser output to transfer heat to the foil tab located below the current collector. However, in this disclosure, the foil tab is placed on the current collector, thereby enabling welding with relatively low output. In this disclosure, because it is not necessary to melt the lower portion of the current collector, the thickness of the current collector can be increased to protect the separator, thereby also improving the durability of the secondary battery.

[0101] Figure 12 This is a flowchart illustrating a method for manufacturing a secondary battery according to an embodiment of the present disclosure. Figure 13 This is a view illustrating a plurality of first foil tabs and a plurality of second foil tabs grouped separately in a secondary battery according to an embodiment of the present disclosure.

[0102] Figure 14a and Figure 14bThis is a view illustrating a current collector in a secondary battery according to an embodiment of the present disclosure, which is disposed at one end of the electrode portion and welded to a plurality of first foil tabs and a plurality of second foil tabs. Figure 15a , Figure 15b and Figure 15c This is a view illustrating a current collector in a secondary battery according to an embodiment of the present disclosure, disposed between and welded to a plurality of first foil contacts and a plurality of second foil contacts.

[0103] Figure 16 This is a view illustrating the welding direction during the welding of the current collector and the first foil tab in a secondary battery according to an embodiment of the present disclosure. Figure 17 This is a view illustrating a current collector welded to a first foil tab and a second foil tab in a secondary battery according to an embodiment of the present disclosure. Figure 18 This is a view illustrating a covering element disposed on the portion of the current collector and the first foil tab welded together in a secondary battery according to an embodiment of the present disclosure. Figure 19 This is a view illustrating a cover assembly connected to an electrode assembly in a secondary battery according to an embodiment of the present disclosure.

[0104] like Figure 12 As shown, in order to manufacture a secondary battery according to an embodiment of the present disclosure, an electrode assembly 1200 is prepared (S1100). The electrode assembly 1200 includes an electrode portion 1210 and a plurality of first foil tabs 1220 and a plurality of second foil tabs 1230 formed on one end of the electrode portion 1210.

[0105] A plurality of first foil tabs 1220 and a plurality of second foil tabs 1230 are disposed on one end of the electrode portion 1210. When the plurality of electrode plates forming the electrode portion 1210 are stacked, the plurality of first foil tabs 1220 overlap each other at a first position, and the plurality of second foil tabs 1230 overlap each other at a second position. In other words, the plurality of first foil tabs 1220 are grouped at the first position, and the plurality of second foil tabs 1230 are grouped at the second position. The first and second positions are spaced apart from each other on the electrode plates, and the grouped plurality of first foil tabs 1220 and the grouped plurality of second foil tabs 1230 may be spaced apart in the width direction (y-direction) and the longitudinal direction (x-direction) of the electrode assembly 1200. Figure 13 As shown, a group of multiple first foil tabs 1220 can be placed on one end of the electrode assembly in the width direction (y direction), and a group of multiple second foil tabs 1230 can be placed on the other end of the electrode assembly 1200 in the width direction (y direction).

[0106] Next, the current collector 1300 is disposed on one end of the electrode portion 1210 (S1200). To connect the plurality of foil tabs 1220 and 1230 to the current collector 1300, in this embodiment, the foil tabs 1220 and 1230 having the same polarity are divided into two groups and soldered to the current collector 1300. The plurality of first foil tabs 1220 and the plurality of second foil tabs 1230 are grouped at a first position and a second position, respectively, at one end of the electrode portion 1210. The grouped plurality of first foil tabs 1220 and the plurality of second foil tabs 1230 are spaced apart in the width direction and the longitudinal direction of the electrode assembly 1200. The current collector 1300 is disposed on the portion of the electrode portion 1210 where the plurality of first foil tabs 1220 and the plurality of second foil tabs 1230 are not formed (see [reference]). Figure 14a ).

[0107] The first foil tab 1220 and the second foil tab 1230 are each bent toward the upper surface of the current collector 1300 (S1300). A plurality of first foil tabs 1220 are bent onto the upper surface of the first current collecting portion 1310 of the current collector 1300, and a plurality of second foil tabs 1230 are bent onto the upper surface of the second current collecting portion 1320 of the current collector 1300. The plurality of first foil tabs 1220 and the plurality of second foil tabs 1230 are bent in opposite directions (see [reference]). Figure 14b ).

[0108] The welding current collector 1300 and the first foil tabs 1220 and second foil tabs 1230 placed on the current collector 1300 are described in S1400. Multiple first foil tabs 1220 are welded to a first current collector portion 1310, and multiple second foil tabs 1230 are welded to a second current collector portion 1320. Welding can be performed from the upper sides of the multiple first foil tabs 1220 and the multiple second foil tabs 1230. Methods such as ultrasonic welding and laser welding can be used for welding.

[0109] In this embodiment, although the multiple foil tabs 1220 and 1230 are directly bent onto the current collector 1300 and welded to the current collector 1300, in other embodiments, the multiple foil tabs may be pre-welded such that in the first foil tab 1220, the first foil tab 1220 is welded to each other, and in the second foil tab 1230, the second foil tab 1230 is welded to each other and then welded to the current collector 1300.

[0110] like Figure 15aAs shown, before setting the current collector 1300, the first foil patch 1220 and the second foil patch 1230 can be initially welded together, such that the first foil patch 1220 is welded to each other, and the second foil patch 1230 is welded to each other. The current collector 1300 is then positioned between the initially welded first foil patch 1220 and the initially welded second foil patch 1230 (see [reference]). Figure 15b Furthermore, the first foil tab 1220 and the second foil tab 1230 can each be bent onto the current collector 1300 and soldered to the current collector 1300 (see [link]). Figure 15c In this case, after the current collector 1300 is set, the first foil tab 1220 and the second foil tab 1230 can be easily bent onto the current collector 1300.

[0111] like Figure 16 As shown, during welding, welding can be performed from a plurality of first foil tabs 1220 toward the first current collector 1310 in the first current collector section 1310, and welding can be performed from a plurality of second foil tabs 1230 toward the second current collector section 1320 in the second current collector section 1320.

[0112] When welding is complete, the first foil patch 1220 and the second foil patch 1230 are connected to the current collector 1300 (see [link]). Figure 17 Because multiple foil tabs 1220 and 1230 are directly welded to the current collector 1300, the foil tabs do not need to be very long, thus reducing production costs. Furthermore, there is no need to provide bending space for the multiple foil tabs 1220 and 1230, which further increases the capacity of the secondary battery.

[0113] like Figure 18 As shown, in this embodiment, after the welding of the plurality of foil tabs 1220 and 1230 is completed, a covering element 1360 may be provided on each welded portion, namely each of the first current collector portion 1310 and the second current collector portion 1320. The covering element 1360 may cover at least a portion of the electrode assembly 1200 and the current collector 1300.

[0114] Cover element 1360 may include insulating material. Cover element 1360 may be an insulating tape. Current collector protrusion 1331 may be exposed and not covered by cover element 1360. Each of terminals 1420 and 1420a may be coupled to the corresponding current collector protrusion 1331. Because each welded portion is covered by cover element 1360, the insulation structure of cover plate 1400 can be further simplified.

[0115] In order for the cover element 1360 to smoothly cover the soldered portion, in this embodiment, the width w1 of the cover element 1360 can be 1 to 1.2 times the width w2 of the first foil tab and the second foil tab.

[0116] An electrode assembly 1200 with a current collector 1300 welded to it is housed in a box 1100. A cover assembly 1400 seals the opening of the box 1100. Figure 19 As shown, after the current collection protrusion 1331 is inserted into the through hole of the terminal 1420 of the cover assembly 1400, the outer peripheral surface of the end of the current collection protrusion 1331 can be welded to the inner peripheral surface of the end of the through hole.

[0117] When the current collector is welded to the upper portion of the foil tab, the current collector needs to be relatively thin to transfer heat to the foil tab located below it, thus reducing the durability of the secondary battery. However, in this disclosure, because multiple foil tabs are bent onto and welded to the current collector, sufficient thickness of the current collector can be ensured, and the foil tabs can be welded to the current collector more effectively.

[0118] Furthermore, in this disclosure, because multiple foil pieces with the same polarity are divided into two groups and welded, the foil pieces can be stably welded without any unwelded portions.

[0119] In this implementation, the output of the welding equipment can be adjusted according to the position of each foil piece during the welding operation.

[0120] A battery module can be constructed by including multiple secondary batteries according to embodiments of the present disclosure. Multiple secondary batteries can be connected to each other via busbars or the like to construct a battery module. Alternatively, a battery pack can be constructed by including multiple battery modules. A battery pack can be constructed by arranging multiple battery modules in an upper and lower housing constituting a pack housing. Furthermore, the battery pack can be installed in a vehicle that transports or moves loads or personnel, or moves while performing operations. Such vehicles can include bicycles, heavy equipment, agricultural and fishing equipment, automobiles, buses, and airplanes. Here, the automobile can be an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The automobile can include a four-wheeled vehicle or a two-wheeled vehicle. The vehicle can operate by receiving power from the battery pack.

[0121] Although this disclosure has been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes or modifications may be made to this disclosure by adding, altering, or deleting components without departing from the spirit of this disclosure as defined in the appended claims. It should be noted that such changes or modifications also fall within the scope of this disclosure.

Claims

1. A secondary battery, comprising: An electrode assembly, the electrode assembly including an electrode portion and a plurality of first foil tabs and a plurality of second foil tabs formed on one end of the electrode portion; as well as A current collector is disposed on the upper portion of the electrode portion and includes a first current collector portion, a second current collector portion, and a connecting portion. The first current collector portion is soldered to a plurality of first foil tabs, and the second current collector portion is soldered to a plurality of second foil tabs. The connecting portion is connected to the first current collector portion at a lower portion on a first side of the connecting portion and to the second current collector portion at an upper portion on a second side of the connecting portion. The connecting portion has a current collector protrusion. Wherein, the first current collecting portion and the second current collecting portion extend vertically from the first side and the second side of the connecting portion, respectively, and In this configuration, a plurality of first foil tabs are bent in a direction toward the first current collection portion, and a plurality of second foil tabs are bent in a direction opposite to the bending direction of the first foil tabs, toward the second current collection portion.

2. The secondary battery according to claim 1, wherein, Multiple first foil tabs and multiple second foil tabs are respectively soldered onto the first current collector and the second current collector.

3. The secondary battery according to claim 1, wherein, The electrode portion includes a plurality of first electrode plates and a plurality of second electrode plates. A first foil tab is formed on the first electrode plate at a first position, and a second foil tab is formed on the plurality of second electrode plates at a second position. The first electrode plate and the second electrode plate have the same polarity.

4. The secondary battery according to claim 1, wherein, The plurality of first foil tabs and the plurality of second foil tabs are spaced apart from each other in the width direction (y direction) and the longitudinal direction (x direction) of the electrode assembly.

5. The secondary battery according to claim 1, wherein, In the first foil patch, a plurality of first foil patches are pre-welded to each other, and in the second foil patch, a plurality of second foil patches are pre-welded to each other.

6. The secondary battery according to claim 1, wherein, An insulator is provided below the lower surface of the current collector.

7. The secondary battery according to claim 1, wherein, The current collector is disposed in the region on one end of the electrode portion where the plurality of first foil tabs and the plurality of second foil tabs are not formed.

8. The secondary battery according to claim 1, wherein, The current collector is disposed between a plurality of first foil tabs and a plurality of second foil tabs on one end of the electrode portion.

9. The secondary battery according to claim 1, wherein, The flow collection protrusion is formed of the same material as the connecting portion.

10. The secondary battery according to claim 1, wherein, The flow collection protrusion is formed of a material different from that of the connecting portion.

11. The secondary battery according to claim 1, wherein, The thickness of the current collector is in the range of 0.5 mm to 3.0 mm.

12. A method for manufacturing a secondary battery, the method comprising: The preparation operation involves preparing an electrode assembly, the electrode assembly comprising an electrode portion and a plurality of first foil tabs and a plurality of second foil tabs formed on one end of the electrode portion; The current collector setting operation involves placing the current collector in the region on one end of the electrode portion where the plurality of first foil tabs and the plurality of second foil tabs are not formed; The bending operation involves bending a plurality of first foil tabs along the direction toward the upper surface of the first collecting portion of the current collector, and bending a plurality of second foil tabs along the direction opposite to the bending direction of the first foil tabs, toward the upper surface of the second collecting portion of the current collector. as well as The welding operation involves welding multiple bent first foil tabs and multiple bent second foil tabs to the current collector.

13. The method for manufacturing a secondary battery according to claim 12, further comprising, after the preparation operation: The preliminary welding operation involves performing preliminary welding on multiple first foil pieces in the first foil piece and preliminary welding on multiple second foil pieces in the second foil piece.

14. The method for manufacturing a secondary battery according to claim 12, in, The current collector includes a connecting portion with a current collecting protrusion. The first current collection portion is vertically connected to the lower portion of the first side of the connecting portion, and the second current collection portion is vertically connected to the upper portion of the second side of the connecting portion.

15. The method for manufacturing a secondary battery according to claim 12, wherein, In the current collector, the first current collector portion and the second current collector portion are made of the same material as the first foil sheet and the second foil sheet.

16. The method for manufacturing a secondary battery according to claim 12, wherein, An insulator is provided below the lower surface of the current collector.

17. The method for manufacturing a secondary battery according to claim 12, wherein, In the welding operation, in the first current collection section, welding is performed from a plurality of first foil tabs toward the first current collection section, and in the second current collection section, welding is performed from a plurality of second foil tabs toward the second current collection section.

18. A battery module comprising a secondary battery according to any one of claims 1 to 11.

19. A battery pack comprising the battery module according to claim 18.

20. A means of transport comprising the battery pack according to claim 19.

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