Method for manufacturing secondary battery, secondary battery, battery module comprising same, battery pack, and transportation means

Abstract

The present invention relates to a method for manufacturing a secondary battery, a secondary battery, a battery module comprising same, a battery pack, and a transportation means. The secondary battery, according to the present invention, may comprise an electrode assembly and a current collector plate. The electrode assembly may include an electrode unit and a plurality of first foil tabs and a plurality of second foil tabs which are formed at one end of the electrode unit. The current collector plate may include a first current collector portion welded to the plurality of first foil tabs and a second current collector portion welded to the plurality of second foil tabs. The plurality of first foil tabs may be bent in one direction toward the first current collector portion of the current collector plate, and the plurality of second foil tabs may be bent in a direction opposite to that of the first foil tabs toward the second current collector portion of the current collector plate. The present invention can prevent the occurrence of an unwelded portion in some foil tabs when a large number of foil tabs are welded to the current collector plate.

Description

Method for manufacturing a secondary battery, secondary battery, battery module including the same, battery pack and transportation means

[0001] The present invention relates to a method for manufacturing a secondary battery, a secondary battery, a battery module including the same, a battery pack, and a means of transportation, and more particularly, to a method for manufacturing a secondary battery, a secondary battery, a battery module including the same, a battery pack, and a means of transportation, wherein the secondary battery includes an electrode assembly and a current collector, the current collector having a connection portion and a first current collector portion and a second current collector portion extending vertically from one side and the other side of the connection portion, respectively, a plurality of first foil tabs are bent in one direction toward the first current collector portion, and a plurality of second foil tabs are bent in the opposite direction to the first foil tabs toward the second current collector portion.

[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 an 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 foil tabs and collector plates of the electrode assembly. When welding the foil tabs and collector plates, the foil tabs are bent in the bending direction to increase the contact area between the foil tabs and the collector plate, and the collector plate is then placed on top of the foil 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 plate and the foil tabs positioned beneath it. Furthermore, as secondary batteries increase in capacity, the number of foil tabs that must be welded simultaneously increases, raising concerns that tabs located far from the current collector plate may not be properly welded.

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

[0007] An object of the present invention is to provide a secondary battery and a method for manufacturing the same that can prevent an electrode assembly from being affected when welding a foil tab and a collector plate.

[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 foil tabs to a current collector plate when welding the foil tabs and the current collector plate.

[0009] A secondary battery according to one aspect of the present invention may include an electrode assembly and a current collector. The electrode assembly may include an electrode portion, a plurality of first foil tabs formed at one end of the electrode portion, and a plurality of second foil tabs. The current collector may be disposed on an upper portion of the electrode portion, and may include a first current collector, a second current collector, and a connecting portion. The first current collector may be welded to the plurality of first foil tabs. The second current collector may be welded to the plurality of second foil tabs. The connecting portion may have a lower end connected to the first current collector, and an upper end connected to the second current collector. The first current collector and the second current collector may extend vertically from one end and the other end of the connecting portion, respectively. The plurality of first foil tabs may be bent in one direction toward the first current collector, and the plurality of second foil tabs may be bent in an opposite direction to the first foil tab toward the second current collector.

[0010] According to one aspect of the present invention, a plurality of first foil tabs can be welded on the first current collector, and a plurality of second foil tabs can be welded on the second current collector.

[0011] An electrode section according to one aspect of the present invention may include a plurality of first electrode plates having first foil tabs formed at first positions, and a plurality of second electrode plates having second foil tabs formed at second positions. The first electrode plates and the second electrode plates may have the same polarity.

[0012] According to one aspect of the present invention, a plurality of first foil tabs and a plurality of second foil tabs may be spaced apart in the width direction (y direction) and the length direction (x direction) of the electrode assembly.

[0013] According to one aspect of the present invention, the plurality of first foil tabs may be pre-welded to each other, and the plurality of second foil tabs may be pre-welded to each other.

[0014] An insulating member may be arranged on the lower surface of the current collector plate according to one aspect of the present invention.

[0015] According to one aspect of the present invention, a current collector plate may be placed at one end of the electrode portion, in a portion where the plurality of first foil tabs and the plurality of second foil tabs are not formed.

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

[0017] The current collector protrusion according to one aspect of the present invention may be formed of the same material as the connecting portion.

[0018] The current collector according to one aspect of the present invention may be formed of a material different from that of the connecting portion.

[0019] The thickness of the current collector plate according to one aspect of the present invention may be 0.5 to 3.0 mm.

[0020] A method for manufacturing a secondary battery according to one aspect of the present invention may include a preparation step in which an electrode assembly having 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 is prepared, a current collector plate arrangement step in which a current collector plate is arranged at a portion of the 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 step in which the plurality of first foil tabs are bent in one direction toward an upper surface of a first current collector portion of the current collector plate and the plurality of second foil tabs are bent in a direction opposite to the first foil tabs toward an upper surface of a second current collector portion of the current collector plate, and a welding step in which the bent plurality of first foil tabs and the plurality of second foil tabs and the current collector plate are welded.

[0021] After the preparation step according to one aspect of the present invention, the plurality of first foil tabs may further include a first welding step in which the first foil tabs are first welded to each other, and the plurality of second foil tabs are first welded to each other.

[0022] A current collector plate according to one aspect of the present invention may have a connecting portion having a current collector projection. The first current collector may be vertically connected to a lower end of one side of the connecting portion, and the second current collector may be vertically connected to an upper end of the other side of the connecting portion.

[0023] In a current collector plate according to one aspect of the present invention, the first current collector and the second current collector may be made of the same material as the first foil tab and the second foil tab.

[0024] An insulating member may be arranged on the lower surface of the current collector plate according to one aspect of the present invention.

[0025] In a welding step according to one aspect of the present invention, welding may be performed from the plurality of first foil tabs toward the first collector in the first collector, and welding may be performed from the plurality of second foil tabs toward the second collector in the second collector.

[0026] A battery module according to one aspect of the present invention may include the secondary battery.

[0027] A battery pack according to one aspect of the present invention may include the battery module.

[0028] A means of transportation according to one aspect of the present invention may include the battery pack.

[0029] 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 a foil tab and a current collector plate.

[0030] The purpose of the secondary battery and the manufacturing method thereof according to an embodiment of the present invention is to prevent unwelded portions from occurring in some foil tabs when welding a large number of foil tabs and a current collector plate.

[0031] FIG. 1 is a drawing showing a secondary battery according to one embodiment of the present invention.

[0032] FIG. 2 is a drawing showing a secondary battery according to one embodiment of the present invention.

[0033] FIG. 3 is a drawing showing an electrode assembly in which a plurality of first and second foil tabs are formed on an electrode portion in a secondary battery according to one embodiment of the present invention.

[0034] FIG. 4a and FIG. 4b are drawings showing a first electrode plate and a second electrode plate in a secondary battery according to one embodiment of the present invention.

[0035] FIG. 5a and FIG. 5b are drawings showing a third electrode plate and a fourth electrode plate in a secondary battery according to one embodiment of the present invention.

[0036] FIG. 6 is a drawing showing a current collector plate in a secondary battery according to one embodiment of the present invention.

[0037] FIG. 7a and FIG. 7b are drawings showing a current collector plate in a secondary battery according to one embodiment of the present invention.

[0038] FIG. 8a and FIG. 8b are drawings showing that a current collector plate has an insulating member in a secondary battery according to one embodiment of the present invention.

[0039] FIG. 9 is a drawing showing a state in which a current collector plate is arranged on one end of an electrode portion in a secondary battery according to one embodiment of the present invention.

[0040] FIG. 10 is a drawing showing a state in which a current collector plate and first and second foil tabs are welded in a secondary battery according to one embodiment of the present invention.

[0041] FIG. 11 is a drawing showing a cross-section of a secondary battery in which a current collector plate and a first foil tab are welded according to one embodiment of the present invention.

[0042] Figure 12 is a flowchart showing a method for manufacturing a secondary battery according to one embodiment of the present invention.

[0043] FIG. 13 is a drawing showing a state in which a plurality of first foil tabs and a plurality of second foil tabs are each grouped in a secondary battery according to one embodiment of the present invention.

[0044] FIG. 14a and FIG. 14b are drawings showing a state in which a current collector plate is arranged on one end of an electrode portion and welded with a plurality of first foil tabs and a plurality of second foil tabs in a secondary battery according to one embodiment of the present invention.

[0045] FIG. 15a, FIG. 15b, and FIG. 15c are drawings showing a state in which a current collector is placed between first and second foil tabs that are first welded in a secondary battery according to one embodiment of the present invention, and is welded to a plurality of first foil tabs and a plurality of second foil tabs.

[0046] FIG. 16 is a drawing showing the welding progress direction when welding a current collector plate and a first foil tab in a secondary battery according to one embodiment of the present invention.

[0047] FIG. 17 is a drawing showing a state in which a current collector plate and first and second foil tabs are welded in a secondary battery according to one embodiment of the present invention.

[0048] FIG. 18 is a drawing showing a state in which a cover member is placed at a portion where a current collector plate and a first foil tab are welded in a secondary battery according to one embodiment of the present invention.

[0049] FIG. 19 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053]

[0054] FIG. 1 is a drawing showing a secondary battery according to one embodiment of the present invention, FIG. 2 is a drawing showing a secondary battery according to one embodiment of the present invention, and FIG. 3 is a drawing showing an electrode assembly in which a plurality of first and second foil tabs are formed on an electrode portion in a secondary battery according to one embodiment of the present invention.

[0055] FIGS. 4A and 4B are drawings showing a first electrode plate and a second electrode plate in a secondary battery according to one embodiment of the present invention, FIGS. 5A and 5B are drawings showing a third electrode plate and a fourth electrode plate in a secondary battery according to one embodiment of the present invention, and FIG. 6 is a drawing showing a current collector plate in a secondary battery according to one embodiment of the present invention.

[0056] As illustrated in FIGS. 1 and 2, a secondary battery (1000) according to one embodiment of the present invention includes a case (1100), an electrode assembly (1200), a collector plate (1300), and a cap assembly (1400).

[0057] The case (1100) forms the exterior of the secondary battery (100). The case (1100) may have a space formed therein to accommodate an electrode assembly (1200), and an opening may be formed on one side. In the present embodiment, the case (1100) has a rectangular parallelepiped shape, but is not limited thereto and may be modified in various ways. The case (1100) may be made of a sturdy material capable of protecting the electrode assembly (1200) accommodated therein. For example, the case (1100) may be made of a metal such as aluminum or stainless steel.

[0058] An electrolyte may be accommodated together with the electrode assembly (1200) inside the 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.

[0059] An electrode assembly (1200) is accommodated inside a case (1100). As illustrated in FIG. 3, 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 arranged at one end of the electrode portion (1210). The plurality of first foil tabs (1220) are aligned with each other, and the plurality of second foil tabs (1230) are aligned with each other. The plurality of first foil tabs (1220) and the plurality of second foil tabs (1230) are arranged so as not to overlap in the width direction (y direction) and the length direction (x direction) of the electrode assembly (1200).

[0060] Specifically, the electrode unit (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.

[0061] An active material may be applied to a plurality of first electrode plates (1211), a plurality of second electrode plates (1212), a plurality of third electrode plates (1213), and a plurality of fourth electrode plates (1214). An active material such as a transition metal oxide may be applied to a metal plate such as aluminum on a plurality of first electrode plates (1211) and a plurality of second electrode plates (1212). The plurality of first electrode plates (1211) and the plurality of second electrode plates (1212) may have the same polarity and may be positive electrode plates. The plurality of third electrode plates (1213) and the plurality of fourth electrode plates (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 plates (1213) and the plurality of fourth electrode plates (1214) may have the same polarity and may be negative electrode plates.

[0062] The separator is positioned between the plurality of first to fourth electrode plates (1211, 1212, 1213, 1214) to prevent short circuits between the plurality of first to fourth electrode plates (1211, 1212, 1213, 1214). The material of the separator may be polyethylene, polypropylene, or a composite thereof.

[0063] The electrode part (1210) can be formed by positioning a separator between the first electrode plate (1211) and the third electrode plate (1213), and the second electrode plate (1212) and the fourth electrode plate (1214) which are sequentially arranged. That is, in one embodiment, the electrode part (1210) is formed by stacking tens to hundreds of times in the order of the first electrode plate (1211), the separator, the third electrode plate (1213), and the separator on one side of the electrode part (1210), and by stacking tens to hundreds of times in the order of the second electrode plate (1212), the separator, the fourth electrode plate (1214), and the separator on the other side of the electrode part (1210). In another embodiment, the electrode portion (1210) may be formed by sequentially stacking a first electrode plate (1211), a separator, a third electrode plate (1213), a separator, a second electrode plate (1212), a separator, a fourth electrode plate (1214), and a separator, and then winding the stack.

[0064] 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.

[0065] Foil tabs (1220, 1230, 1240, 1250) on which no active material is applied are formed on one end of a plurality of first to fourth electrode plates (1211, 1212, 1213, 1214). In one embodiment, the electrode plates (1211, 1212, 1213, 1214) and the foil tabs (1220, 1230, 1240, 1250) may be formed integrally by cutting a predetermined portion of a single metal plate using a laser or the like to leave the electrode plates (1211, 1212, 1213, 1214) and the foil tabs (1220, 1230, 1240, 1250). A plurality of foil tabs (1220, 1230, 1240, 1250) can be formed in a direction toward the cap assembly (1400).

[0066] A first foil tab (1220) is formed at a first position of a first electrode plate (1211). A second foil tab (1230) is formed at a second position of a second electrode plate (1212) (Figs. 4a and 4b). Similarly, a third foil tab (1240) may be formed at a third position of a third electrode plate (1213), and a fourth foil tab (1250) may be formed at a fourth position of a fourth electrode plate (1214) (Figs. 5a and 5b).

[0067] A plurality of first electrode plates (1211) and a plurality of third electrode plates (1213) can be alternately stacked with a separator between them. A stack of a plurality of first electrode plates (1211) and a plurality of third electrode plates (1213) forms one half of an electrode portion (1210).

[0068] A plurality of second electrode plates (1212) and a plurality of fourth electrode plates (1214) can be alternately stacked with a separator between them. The stack of the plurality of second electrode plates (1212) and the plurality of fourth electrode plates (1214) forms the remaining half of the electrode portion (1210).

[0069] A stack of a plurality of first electrode plates (1211) and a plurality of third electrode plates (1213) and a stack of a plurality of second electrode plates (1212) and a plurality of fourth electrode plates (1214) are connected in the width direction of the electrode part (1210). When forming the electrode assembly (1200), after stacking a plurality of first electrode plates (1211) and a plurality of third electrode plates (1213), a plurality of second electrode plates (1212) and a plurality of fourth electrode plates (1214) can be stacked.

[0070] When a plurality of first to fourth electrode plates (1211, 1212, 1213, 1214) are stacked, a plurality of first foil tabs (1220) overlap each other at a first position. A plurality of second foil tabs (1230) overlap each other at a second position. That is, among a plurality of first foil tabs (1220) and a plurality of second foil tabs (1230) having the same polarity, a plurality of first foil tabs (1220) are grouped at a first position, and a plurality of second foil tabs (1230) are grouped at a second position. The first position and the second position are spaced apart from each other on the electrode plates, and the plurality of first foil tabs (1220) and the plurality of second foil tabs (1230) that are grouped respectively can be spaced apart in the width direction (y direction) and the length direction (x direction) of the electrode assembly (1200).

[0071] In order to stably weld a large number of foil tabs, foil tabs of the same polarity are formed by dividing them into two groups spaced apart from each other, and each group is welded to a respective current collector plate. That is, one foil tab is formed on one electrode plate, but by forming the foil tabs at different positions on each electrode plate, two groups of foil tabs at different positions on the same polarity are formed after lamination of the electrode plates. In another embodiment, two or more foil tabs at different positions on the same polarity may be formed.

[0072] When a plurality of first to fourth electrode plates (1211, 1212, 1213, 1214) are stacked, a plurality of third foil tabs (1240) overlap each other at a third position, and a plurality of fourth foil tabs (1250) overlap each other at a fourth position. That is, a plurality of third foil tabs (1240) are grouped at the third position, and a plurality of fourth foil tabs (1250) are grouped at the fourth position. The third position and the fourth position are spaced apart from each other on the electrode plates, and the plurality of third foil tabs (1240) and the plurality of fourth foil tabs (1250) that are grouped respectively can be spaced apart in the width direction (y direction) and the length direction (x direction) of the electrode assembly (1200).

[0073] The plurality of third foil tabs (1240) and the plurality of fourth foil tabs (1250) may be foil tabs of the same polarity.

[0074] A plurality of foil tabs (1220, 1230, 1240, 1250) overlapping at each location can be connected to a current collector plate by ultrasonic welding, laser welding, etc. to facilitate the movement of current.

[0075] As illustrated in FIG. 6, the collector plate (1300) may include a first collector portion (1310), a second collector portion (1320), a connecting portion (1330), and a collector projection (1331).

[0076] A first foil tab (1220) can be welded to the first collector (1310), and a second foil tab (1230) can be welded to the second collector (1320).

[0077] The structure of the collector plate will be described later.

[0078] The cap assembly (1400) seals the opening of the case (1100) in which the electrode assembly (1200) is accommodated. The cap assembly (1400) includes a cap plate (1410) and terminals (1420, 1420a).

[0079] 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.

[0080] A vent hole (1411) and an electrolyte injection port (1412) may be formed in the cap plate (1410). The vent hole (1411) is 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).

[0081] The terminals (1420, 1420a) may be formed to protrude from the cap plate (1410). The terminals (1420, 1420a) are electrically connected to the foil tabs (1220, 1220a) through the current collector plate (1300). The terminals (1420, 1420a) may be formed in the shape of a circular or rectangular plate.

[0082] A through hole may be formed in the terminal (1420, 1420a). A collector projection (1331) is 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.

[0083] An insulating member (1430, 1430a) may be positioned between the terminal (1420, 1420a) and the cap plate (1410). The insulating member (1430, 1430a) insulates the terminal (1420, 1420a) and the cap plate (1410) from each other.

[0084]

[0085] FIGS. 7A and 7B are drawings showing a current collector plate in a secondary battery according to one embodiment of the present invention, and FIGS. 8A and 8B are drawings showing that a current collector plate in a secondary battery according to one embodiment of the present invention includes an insulating member.

[0086] FIG. 9 is a drawing showing a state in which a current collector plate is arranged on one end of an electrode portion in a secondary battery according to one embodiment of the present invention, FIG. 10 is a drawing showing a state in which a current collector plate and first and second foil tabs are welded in a secondary battery according to one embodiment of the present invention, and FIG. 11 is a drawing showing a cross-section in which a current collector plate and a first foil tab are welded in a secondary battery according to one embodiment of the present invention.

[0087] As illustrated in FIG. 7a, the collector plate (1300) may include a first collector portion (1310), a second collector portion (1320), and a connecting portion (1330).

[0088] The current collector plate (1300) has a 'Z' shape. The current collector plate (1300) is extended with a first current collector (1310) and a second current collector (1320) connected to both sides of the connection portion (1330) centered on the connection portion (1330). The first current collector (1310) may be connected to a lower side of one side of the connection portion (1330), and the second current collector (1320) may be connected to an upper side of the other side of the connection portion (1330) in a vertical direction (x direction). The first current collector (1310) and the second current collector (1320) may have one side connected to the connection portion (1330) and may extend in opposite directions along the longitudinal direction (x direction) of the electrode assembly (1200).

[0089] That is, the first collector (1310) and the second collector (1320) are arranged to be misaligned in the longitudinal direction with the connection (1330) as the center. Due to the misaligned arrangement of the first collector (1310) and the second collector (1320), the shape in which the first collector (1310), the second collector (1320), and the connection (1330) are connected may be a staircase or a “Z”. The longitudinal center line (C1) of the first collector (1310) and the longitudinal center line (C2) of the second collector (1320) may be parallel to each other.

[0090] The first collector (1310), the second collector (1320), and the connection (1330) are formed integrally from the same material, and the first collector (1310) and the second collector (1320) are electrically connected.

[0091] An insulating member (1340) may be placed under the collector plate (1300) (Figs. 8A and 8B). The insulating member (1340) may be an insulating plate or an insulating film. The foil tabs (1220, 1230) and the electrode portion (1210) may be further protected by the insulating member (1340).

[0092] The width of the first collector (1310) and the second collector (1320) in the collector plate (1300) may be 0.3 to 0.5 times the width of the electrode assembly (1200).

[0093] As illustrated in FIG. 9, the current collector plate (1300) can be placed at one end of the electrode portion (1210) in a portion where a plurality of first foil tabs (1220) and a plurality of second foil tabs (1230) are not formed. Since the plurality of first foil tabs (1220) and the plurality of second foil tabs (1230) are spaced apart in the width direction and the length direction of the electrode assembly (1200), an area where no foil tabs are formed is formed on one side of the plurality of first foil tabs (1220) and the plurality of second foil tabs (1230). The current collector plate (1300) is placed so that the first current collector portion (1310) and the second current collector portion (1320) are respectively positioned in the portion where no foil tabs are formed.

[0094] The first current collector (1310) is welded with a plurality of first foil tabs (1220). The plurality of first foil tabs (1220) can be bent and welded onto the first current collector (1310). The second current collector (1320) is welded with a plurality of second foil tabs (1230). The plurality of second foil tabs (1230) can be bent and welded onto the second current collector (1320). That is, the plurality of first foil tabs (1220) and the plurality of second foil tabs (1230) are bent in opposite directions and welded.

[0095] Welding is performed on a plurality of first foil tabs (1220) and a plurality of second foil tabs (1230). Welding may be performed using a method such as ultrasonic welding or laser welding. During welding, welding may be performed from a plurality of first foil tabs (1220) toward a first collector (1310) of a collector plate (1300), and welding may be performed from a plurality of second foil tabs (1230) toward a second collector (1320) of a second collector plate (1300).

[0096] As illustrated in FIG. 10, the first collector (1310) and the second collector (1320) are arranged to be misaligned in the longitudinal direction (x direction) and the width direction (y direction) of the electrode assembly (1200) by the connecting portion (1330), so that the plurality of first foil tabs (1220) and the plurality of second foil tabs (1230) do not interfere with each other when welded to the first collector (1310) and the second collector (1320), respectively.

[0097] Two collector plates (1300) may be provided, and the material of the collector plates (1300) may be the same as that of the first and second foil tabs (1220, 1230) or the third or fourth foil tabs (1240, 1250), respectively. That is, the collector plate (1300) may be formed of aluminum, copper, or nickel.

[0098] The connecting portion (1330) is provided with a current collector protrusion (1331). 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 that 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) and the material of the connecting portion (1330) are the same, the connecting portion (1330) and the current collector protrusion (1231) may be formed as one piece.

[0099] The current collector plate (1300) may have a thickness of 0.5 to 3.0 mm. In the present invention, the current collector plate (1300) is positioned in an area on the electrode portion where no foil tabs are formed, and the thickness of the current collector plate (1300) can be increased by bending the foil tabs (1220, 1230) on the current collector plate (1300) and welding them on top of the foil tabs (1220, 1230). Accordingly, the durability of the secondary battery can also be improved.

[0100] A plurality of micro-grooves or micro-roughnesses may be formed on the upper surface of the current collector plate (1300). The micro-grooves and micro-roughnesses are first melted during welding, and can allow the current collector plate (1300) to be better fused with the foil tabs (1220, 1230).

[0101] Since the present invention positions a foil tab on a current collector plate (1300) and performs welding on the upper portion of the foil tab (Fig. 11), there is no concern about damaging the separator provided in the electrode portion.

[0102] In addition, in the past, a current collector plate was placed on top of a foil tab and then welding was performed, so that high laser power was required to reach the foil tab under the current collector plate, but in the present invention, the foil tab is placed on top of the current collector plate, so welding is possible with a small power. Since the present invention does not require melting all the way to the bottom of the current collector plate, the thickness of the current collector plate can be increased to protect the separator, and accordingly, the durability of the secondary battery can also be improved.

[0103]

[0104] FIG. 12 is a flowchart showing a method for manufacturing a secondary battery according to one embodiment of the present invention, and FIG. 13 is a drawing showing a state in which a plurality of first foil tabs and a plurality of second foil tabs are each grouped in a secondary battery according to one embodiment of the present invention.

[0105] FIGS. 14A and 14B are drawings showing a state in which a current collector plate is arranged at one end of an electrode portion and welded with a plurality of first foil tabs and a plurality of second foil tabs in a secondary battery according to one embodiment of the present invention, and FIGS. 15A, 15B and 15C are drawings showing a state in which a current collector plate is arranged between first and second foil tabs that are first welded and welded with a plurality of first foil tabs and a plurality of second foil tabs in a secondary battery according to one embodiment of the present invention.

[0106] FIG. 16 is a drawing showing a welding progress direction when welding a current collector plate and a first foil tab in a secondary battery according to an embodiment of the present invention, FIG. 17 is a drawing showing a state in which a current collector plate and first and second foil tabs are welded in a secondary battery according to an embodiment of the present invention, FIG. 18 is a drawing showing a state in which a cover member is arranged in a portion where a current collector plate and a first foil tab are welded in a secondary battery according to an embodiment of the present invention, and FIG. 19 is a drawing 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.

[0107] As illustrated in FIG. 12, in order to manufacture a secondary battery according to one embodiment of the present invention, an electrode assembly is prepared (S1100). The electrode assembly (1200) includes an electrode portion (1210), a plurality of first foil tabs (1220) formed at one end of the electrode portion, and a plurality of second foil tabs (1230).

[0108] A plurality of first foil tabs (1220) and a plurality of second foil tabs (1230) are arranged at one end of the electrode portion (1210). When a plurality of electrode plates forming the electrode portion are laminated, 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. That is, 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 position and the second position are spaced apart from each other on the electrode plate, and the plurality of first foil tabs (1220) and the plurality of second foil tabs (1230) that are grouped respectively can be spaced apart in the width direction (y direction) and the length direction (x direction) of the electrode assembly (1200). As illustrated in FIG. 13, a plurality of first foil tabs (1220) each grouped can be arranged at one end in the width direction (y direction) of the electrode assembly, and a plurality of second foil tabs (1230) can be arranged at the other end in the width direction (y direction) of the electrode assembly (1200).

[0109] Next, a current collector (1300) is placed on one end of the electrode portion (S1200). In order to connect a plurality of foil tabs (1220, 1230) to the current collector (1300), in the present embodiment, the foil tabs (1220, 1230) of the same polarity are divided into two groups and welded to the current collector (1300). A plurality of first foil tabs (1220) and a plurality of second foil tabs (1230) are grouped at first and second positions of one end of the electrode portion (1210), respectively. The plurality of first foil tabs (1220) and the plurality of second foil tabs (1230) that are grouped are spaced apart in the width direction and the length direction of the electrode assembly (1200). The collector plate (1300) is placed on a portion of the electrode portion (1210) where a plurality of first foil tabs (1220) and a plurality of second foil tabs (1230) are not formed (Fig. 14a).

[0110] The first foil tab (1220) and the second foil tab (1230) are each bent toward the upper surface of the current collector plate (1300) (S1300). The plurality of first foil tabs (1220) are bent toward the upper surface of the first current collector (1310) of the current collector plate (1300), and the plurality of second foil tabs (1230) are bent toward the upper surface of the second current collector (1320) of the current collector plate (1300). The plurality of first foil tabs (1220) and the plurality of second foil tabs (1230) are bent in opposite directions (Fig. 14b).

[0111] A current collector plate (1300) and first and second foil tabs (1220, 1230) placed on the current collector plate (1300) are welded (S1400). A plurality of first foil tabs (1220) are welded to a first current collector (1310), and a plurality of second foil tabs (1230) are welded to a second current collector (1320). Welding may be performed on top of a plurality of first foil tabs (1220) and a plurality of second foil tabs (1230). Welding may be performed using a method such as ultrasonic welding or laser welding.

[0112] In this embodiment, a plurality of foil tabs (1220, 1230) are bent and welded directly onto the collector plate (1300), but in another embodiment, a plurality of foil tabs may be welded in advance, first foil tabs (1220) and second foil tabs (1230) and then welded to the collector plate (1300).

[0113] As illustrated in FIG. 15a, the first and second foil tabs (1220, 1230) can be first welded to each other before the current collector plate (1300) is placed. The current collector plate (1300) is placed between the first and second foil tabs (1220) and (1230) that have been first welded (FIG. 15b), and the first foil tab (1220) and the second foil tab (1230) can be welded by bending them onto the current collector plate (1300), respectively (FIG. 15c). In this case, after the current collector plate (1300) is placed, the first and second foil tabs (1220, 1230) can be easily bent onto the current collector plate (1300).

[0114] As illustrated in FIG. 16, during welding, in the first collector (1310), welding may be performed from a plurality of first foil tabs (1220) toward the first collector (1310), and in the second collector (1320), welding may be performed from a plurality of second foil tabs (1230) toward the second collector (1320).

[0115] Once welding is complete, the first and second foil tabs (1220, 1230) and the current collector plate (1300) are connected (Fig. 17). Since the plurality of foil tabs (1220, 1230) are welded directly onto the current collector plate (1300), the length of the foil tabs does not need to be long, thereby reducing the cost, and since the folding space of the plurality of foil tabs (1220, 1230) is not required, the capacity of the secondary battery can be further increased.

[0116] Meanwhile, as illustrated in FIG. 18, in one embodiment, after welding of a plurality of foil tabs (1220, 1230) is completed, a cover member (1360) may be placed on the welded portion, i.e., the first collector (1310) and the second collector (1320). The cover member (1360) may cover at least a portion of the electrode assembly (1200) and the collector plate (1300).

[0117] The cover member (1360) may include an insulating material. The cover member (1360) may be an insulating tape. The current collector protrusion (1331) may be exposed without being covered by the cover member (1360). The terminal (1420, 1420a) may be coupled with the current collector protrusion (2331). By covering the welding portion with the cover member (1360), the insulating structure of the cover plate (1400) may be further simplified.

[0118] In order for the cover member (1360) to smoothly cover the welding portion, the width (w1) of the cover member (1360) in this embodiment may be 1 to 1.2 times the width (w2) of the first and second foil tabs.

[0119] The electrode assembly (1200) to which the collector plate (1300) is welded is accommodated in the case (1100), and the cap assembly (1400) seals the opening of the case (1100). At this time, as illustrated in FIG. 19, after the collector projection (1331) is inserted into the through-hole of the terminal (1420) of the cap assembly (1400), the outer surface of the end of the collector projection (1331) and the inner surface of the end of the through-hole can be welded.

[0120] When a collector plate is welded on top of a foil tab, the collector plate must be thin to transfer heat to the foil tabs below, which has resulted in reduced durability. However, the present invention secures the thickness of the collector plate by bending and welding multiple foil tabs onto the collector plate, and allows for more efficient welding of the foil tabs to the collector plate.

[0121] In addition, the present invention can stably weld foil tabs without any unwelded portions by dividing a plurality of foil tabs having the same polarity into two groups and welding them.

[0122] In one embodiment, the output of the welding device may be adjusted depending on the position of the foil tab during the welding step.

[0123]

[0124] Meanwhile, a battery module can be configured by including a plurality of secondary batteries according to the present embodiment. The plurality of secondary batteries can be connected to each other by bus bars or the like to configure a battery module. In addition, a battery pack can be configured by including a plurality of battery modules. The battery pack can be configured by arranging the plurality of battery modules within an upper pack housing and a lower pack housing that constitute a pack housing. In addition, the battery pack can be provided to a means of transportation that moves or works while moving loads, people, etc. Such means of transportation can include a bicycle, heavy equipment, fishing equipment, automobiles, buses, airplanes, etc. Here, the automobile can be an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The automobile can include a four-wheeled or two-wheeled vehicle. The means of transportation can operate by receiving power from the battery pack.

[0125]

[0126] 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

1. An electrode assembly comprising an electrode part, a plurality of first foil tabs and a plurality of second foil tabs formed at one end of the electrode part; and A current collector plate is disposed on the upper portion of the electrode portion, and includes a first current collector welded to the plurality of first foil tabs, a second current collector welded to the plurality of second foil tabs, and a connecting portion having a current collector projection and having the first current collector connected to the lower portion on one side and the second current collector connected to the upper portion on the other side; The first collector and the second collector extend vertically from one side and the other side of the connecting portion, respectively, A secondary battery, wherein the plurality of first foil tabs are bent in one direction toward the first collector, and the plurality of second foil tabs are bent in the opposite direction to the first foil tabs toward the second collector.

2. In paragraph 1, A secondary primary battery, wherein the plurality of first foil tabs are welded on the first collector, and the plurality of second foil tabs are welded on the second collector.

3. In paragraph 1, The above electrode part It comprises a plurality of first electrode plates having a first foil tab formed at a first position and a plurality of second electrode plates having a second foil tab formed at a second position. A secondary battery wherein the first electrode plate and the second electrode plate have the same polarity.

4. In paragraph 1, A secondary battery, wherein the plurality of first foil tabs and the plurality of second foil tabs are spaced apart in the width direction (y direction) and the length direction (x direction) of the electrode assembly.

5. In paragraph 1, A secondary battery, wherein the plurality of first foil tabs are pre-welded to each other, and the plurality of second foil tabs are pre-welded to each other.

6. In paragraph 1, A secondary battery in which an insulating material is placed on the lower surface of the above-mentioned current collector plate.

7. In paragraph 1, A secondary battery, wherein the above current collector plate is disposed at one end of the electrode portion, in a portion where the plurality of first foil tabs and the plurality of second foil tabs are not formed.

8. In paragraph 1, A secondary battery, wherein the above current collector plate is disposed between the plurality of first foil tabs and the plurality of second foil tabs at one end of the electrode portion.

9. In paragraph 1, A secondary battery, wherein the above-mentioned current collector is formed of the same material as the above-mentioned connecting portion.

10. In paragraph 1, A secondary battery, wherein the above-mentioned current collector is formed of a material different from the above-mentioned connecting portion.

11. In paragraph 1, A secondary battery having a thickness of the above current collector plate of 0.5 to 3.0 mm.

12. A preparatory step in which an electrode assembly is prepared, including an electrode part and a plurality of first foil tabs and a plurality of second foil tabs formed at one end of the electrode part; A current collector plate arrangement step in which a current collector plate is arranged on one end of the electrode portion, in a portion where the plurality of first foil tabs and the plurality of second foil tabs are not formed; A bending step in which the plurality of first foil tabs are bent in one direction toward the upper surface of the first current collector of the current collector plate, and the plurality of second foil tabs are bent in the opposite direction to the first foil tabs toward the upper surface of the second current collector of the current collector plate; and A method for manufacturing a secondary battery, comprising a welding step in which the plurality of bent first foil tabs and the plurality of second foil tabs and the current collector plate are welded.

13. In paragraph 12, After the above preparation steps, A method for manufacturing a secondary battery, further comprising a first welding step in which the plurality of first foil tabs are first welded to each other, and the plurality of second foil tabs are first welded to each other.

14. In paragraph 12, The above current collector plate has a connecting portion having a current collector projection, A method for manufacturing a secondary battery, wherein the first collector is vertically connected to one side of the lower portion of the connecting portion, and the second collector is vertically connected to the other side of the upper portion of the connecting portion.

15. In paragraph 12, In the above collector plate, A method for manufacturing a secondary battery, wherein the first current collector and the second current collector are made of the same material as the first foil tab and the second foil tab.

16. In paragraph 12, A method for manufacturing a secondary battery, wherein an insulating material is placed on the lower surface of the above-mentioned current collector plate.

17. In paragraph 12, In the above welding step, A secondary battery manufacturing method, wherein welding is performed from the plurality of first foil tabs toward the first collector in the first collector, and welding is performed from the plurality of second foil tabs toward the second collector in the second collector.

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

19. A battery pack comprising a battery module according to Article 18.

20. A means of transportation comprising a battery pack according to Article 19.

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