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

Abstract

The present invention relates to a method for manufacturing a secondary battery, a secondary battery, and a battery module, a battery pack and a transportation means comprising same. According to the present invention, a current collector plate comprises: a slit unit having a plurality of slits formed in the thickness direction of an electrode assembly; and a connection unit connected to one side of the slit unit and having a support member and a current collecting protrusion. The present invention can minimize the amount of space wasted in a secondary battery when a large number of foil tabs and a current collector plate are welded, reduce costs, and easily connect the current collector plate to the electrode terminal.

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 current collector plate including a slit portion having a plurality of slits extending in the longitudinal direction of an electrode assembly, and a connecting portion connected to one side of the slit portion and having a support member and a current collector protrusion, a secondary battery including the same, and a method for manufacturing the same.

[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 current collector plates of the electrode assembly. When welding the foil tabs and current collector plates, multiple foil tabs are folded and laid flat to increase the contact area between the foil tabs and current collector plates. The current collector plates are then placed on top of the foil tabs and welded.

[0005] However, there is a problem in that the length of the foil tabs must be long in order to bend multiple foil tabs, and the foil tabs require a folding space, which lowers the energy density of the secondary battery.

[0006] Therefore, it is necessary to develop a secondary battery that can increase the energy density of the secondary battery by reducing the folding space of the foil tab and shorten the length of the foil tab.

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

[0008] The purpose of the present invention is to provide a method for manufacturing a secondary battery, which can minimize wasted space within a secondary battery case and reduce cost when welding a large number of foil tabs and collector plates, a secondary battery, a battery module including the same, a battery pack, and a transportation means.

[0009] The purpose of the present invention is to provide a method for manufacturing a secondary battery in which a current collector plate and an electrode terminal can be easily combined, a secondary battery, a battery module including the same, a battery pack, and a transportation means.

[0010] A secondary battery according to one aspect of the present invention includes an electrode assembly and a current collector. The electrode assembly may include an electrode portion and a plurality of foil tabs formed at one end of the electrode portion. The current collector may include a slit portion having a plurality of slits extending in the longitudinal direction of the electrode assembly, and a connecting portion connected to one side of the slit portion and having a support member and a current collector protrusion. The current collector may be disposed on an upper side of the electrode portion and welded to a plurality of foil tabs. The plurality of foil tabs are grouped into at least two foil tab groups, and each foil tab group can pass through a slit of the current collector.

[0011] A plurality of foil tab groups according to one aspect of the present invention can each be first welded.

[0012] According to one aspect of the present invention, a plurality of foil tab groups protruding from the upper portion of the slit of the current collector plate can each be bent toward the upper surface of the current collector plate.

[0013] A foil tab group according to one aspect of the present invention may include at least five foil tabs.

[0014] In a current collector plate according to one aspect of the present invention, the thickness of the connection portion and the thickness of the slit portion may be the same.

[0015] According to one aspect of the present invention, the current collector plate may have a thickness (d1) of a connecting portion greater than a thickness (d2) of a slit portion.

[0016] In a current collector plate according to one aspect of the present invention, the thickness (d3) of the end side of the slit portion may be greater than the thickness (d2) of the inner side of the slit portion.

[0017] According to one aspect of the present invention, a current collector plate may have an insulating member placed at the lower end of a connecting portion.

[0018] According to one aspect of the present invention, a current collector plate may have an insulating member arranged at the lower end of the connection portion and the lower end of the slit portion.

[0019] According to one aspect of the present invention, the current collector plate may have a support member and a current collector projection made of the same material.

[0020] According to one aspect of the present invention, the current collector plate may have a support member and a current collector projection made of different materials.

[0021] A method for manufacturing a secondary battery according to one aspect of the present invention includes a preparation step, a first welding step, a collector plate arrangement step, a bending step, and a second welding step. In the preparation step, an electrode assembly having an electrode portion and a plurality of foil tabs formed at one end of the electrode portion may be prepared. In the first welding step, the plurality of foil tabs may be grouped into at least two foil tab groups, and each foil tab group may be welded to another. In the collector plate arrangement step, the collector plates may be arranged at one end of the electrode portion such that the at least two first-welded foil tab groups each pass through a slit of the collector plate. In the bending step, the foil tab groups protruding above the slit of the collector plate may be bent toward the upper surface of the collector plate. In the second welding step, the plurality of bent foil tab groups and the collector plate may be welded.

[0022] In a bending step according to one aspect of the present invention, a plurality of foil tab groups protruding above the slit of the current collector plate can be bent in one direction.

[0023] In a current collector plate according to one aspect of the present invention, the thickness (d1) of the connection portion may be greater than the thickness (d2) of the slit portion.

[0024] According to one aspect of the present invention, a current collector plate may have an insulating portion arranged at the bottom of a connecting portion.

[0025] According to one aspect of the present invention, a current collector plate may have an insulating member arranged at the lower end of a connecting portion and a lower end of a slit portion.

[0026] The support member and the collector projection of the collector plate according to one aspect of the present invention may be made of the same material.

[0027] The support member and the collector projection of the collector plate according to one aspect of the present invention may be made of different materials.

[0028] A battery module according to one aspect of the present invention may include the secondary battery.

[0029] A battery pack according to one aspect of the present invention may include the battery module.

[0030] A means of transportation according to one aspect of the present invention may include the battery pack.

[0031] A method for manufacturing a secondary battery, a secondary battery, a battery module including the same, a battery pack, and a transportation means according to an embodiment of the present invention can prevent an electrode assembly from being affected when welding a foil tab and a current collector plate.

[0032] The method for manufacturing a secondary battery, the secondary battery, the battery module including the same, the battery pack, and the transportation means according to the embodiment of the present invention can minimize the space wasted within the secondary battery case when welding a large number of foil tabs and collector plates, and reduce the cost.

[0033] A method for manufacturing a secondary battery, a secondary battery, a battery module including the same, a battery pack, and a transportation means according to an embodiment of the present invention can easily combine a current collector plate and an electrode terminal.

[0034] FIG. 1 is a drawing showing a secondary battery according to one embodiment of the present invention.

[0035] FIG. 2 is a drawing showing a secondary battery according to one embodiment of the present invention.

[0036] FIG. 3 is a drawing showing an electrode assembly in which a plurality of foil tabs are formed on an electrode portion in a secondary battery according to one embodiment of the present invention.

[0037] 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.

[0038] FIG. 5a and FIG. 5b are drawings showing a current collector plate in a secondary battery according to one embodiment of the present invention.

[0039] FIG. 6a and FIG. 6b are drawings showing a current collector plate in a secondary battery according to another embodiment of the present invention.

[0040] FIG. 7a, FIG. 7b, and FIG. 7c are drawings showing an insulating member arranged under a current collector plate in a secondary battery according to another embodiment of the present invention.

[0041] Figure 8 is a flowchart showing a method for manufacturing a secondary battery according to one embodiment of the present invention.

[0042] FIG. 9a and FIG. 9b are drawings showing a plurality of foil tabs formed on an electrode portion and side surfaces thereof in a secondary battery according to one embodiment of the present invention.

[0043] FIG. 10A and FIG. 10B are drawings showing a state in which a plurality of foil tabs are grouped into two or more foil tab groups in a secondary battery according to one embodiment of the present invention.

[0044] FIG. 11 is a drawing showing a state in which a current collector plate is arranged on an electrode portion in a secondary battery according to one embodiment of the present invention.

[0045] FIG. 12a and FIG. 12b are drawings showing a state in which a plurality of foil tab groups and a collector plate are welded in a secondary battery according to one embodiment of the present invention.

[0046] FIG. 13 is a drawing showing a state in which a cover member is placed at a portion where a current collector plate and a foil tab group are welded in a secondary battery according to one embodiment of the present invention.

[0047] FIG. 14 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051]

[0052] 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, FIG. 3 is a drawing showing an electrode assembly having a plurality of foil tabs formed on an electrode portion in a secondary battery according to one embodiment of the present invention, and 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.

[0053] 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).

[0054] The case (1100) forms the exterior of the secondary battery (1000). The case (1100) may have a space formed therein to accommodate an electrode assembly (1200), and an opening 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.

[0055] 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.

[0056] An electrode assembly (1200) is accommodated within 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 each disposed at one end of the electrode portion (1210). The plurality of first foil tabs (1220) are aligned with the first foil tabs (1220), and the plurality of second foil tabs (1230) are aligned with the second foil tabs (1230). The plurality of first foil tabs (1220) and the plurality of second foil tabs (1230) may be spaced apart in the longitudinal direction (x direction) of the electrode assembly (1200).

[0057] Specifically, the electrode unit (1210) includes a plurality of first electrode plates (1211), a plurality of second electrode plates (1212), and a separator.

[0058] An active material may be applied to a plurality of first electrode plates (1211) and a plurality of second electrode plates (1212). The plurality of first electrode plates (1211) may be a metal plate such as aluminum to which an active material such as a transition metal oxide may be applied. The plurality of second electrode plates (1212) may be a metal plate such as copper or nickel to which an active material such as graphite or carbon may be applied.

[0059] The separator is positioned between the plurality of first and second electrode plates (1211, 1212) to prevent short circuits between the plurality of first and second electrode plates (1211, 1212). The material of the separator may be polyethylene, polypropylene, or a composite thereof.

[0060] The electrode portion (1210) can be formed by positioning a separator (1213) between first electrode plates (1211) and second electrode plates (1212) that are alternately arranged. That is, in one embodiment, the electrode portion (1210) is formed by alternately stacking a first electrode plate (1211), a separator (1213), a second electrode plate (1212), and a separator (1213) in that order. In another embodiment, the electrode portion (1210) can be formed by arranging a first electrode plate (1211), a separator (1213), and a second electrode plate (1212) in that order and then winding them.

[0061] 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.

[0062] As illustrated in FIGS. 4A and 4B, foil tabs (1220, 1230) on which no active material is applied are formed on one end of each of the plurality of first and second electrode plates (1211, 1212). In one embodiment, the electrode plates (1211, 1212) and the foil tabs (1220, 1230) may be formed integrally by cutting a predetermined portion from a single metal plate using a laser or the like to leave the electrode plates (1211, 1212) and the foil tabs (1220, 1230). The plurality of foil tabs (1220, 1230) may be formed in a direction toward the cap assembly (1400).

[0063] The foil tabs (1220) of the first electrode plate (1211) overlap each other at a first position, and the foil tabs (1230) of the second electrode plate (1212) overlap each other at a second position. In another embodiment, there may be two or more positions where the foil tabs (1220, 1230) overlap each other on each of the first electrode plate (1211) and the second electrode plate (1212). A plurality of foil tabs (1220, 1230) that overlap at the same position may be connected to each other by ultrasonic welding, laser welding, or the like, or may be connected to a current collector plate to facilitate the movement of current.

[0064] The collector plate (1300) has a slit portion (1310) and a connecting portion (1320). The slit portion (1310) has a rectangular shape and extends in the length direction of the electrode assembly (1200). A plurality of slits (1311) are formed in the slit portion (1310).

[0065] The connecting portion (1320) has a rectangular shape and is connected to one side of the slit portion (1310). The connecting portion (1320) may include a support member (1321) and a current collecting projection (1322).

[0066] The structure of the collector plate (1300) will be described later.

[0067] 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).

[0068] 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.

[0069] 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).

[0070] 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.

[0071] A through hole may be formed in the terminal (1420, 1420a). A collector projection (1322) is inserted into the through hole. After the collector projection (1322) is inserted into the through hole, the outer surface of the end of the collector projection (1322) and the inner surface of the end of the through hole may be joined by butt welding.

[0072] An insulating plate (1430, 1430a) may be positioned between the terminal (1420, 1420a) and the cap plate (1410). The insulating plate (1430, 1430a) insulates the terminal (1420, 1420a) and the cap plate (1410) from each other.

[0073]

[0074] FIGS. 5A and 5B are drawings showing a current collector plate in a secondary battery according to one embodiment of the present invention, FIGS. 6A and 6B are drawings showing a current collector plate in a secondary battery according to another embodiment of the present invention, and FIGS. 7A, 7B, and 7C are drawings showing an insulating member arranged under a current collector plate in a secondary battery according to another embodiment of the present invention.

[0075] As illustrated in FIGS. 5A and 5B, the collector plate (1300) may be formed of a rectangular plate. The collector plate (1300) has a slit portion (1310) and a connecting portion (1320).

[0076] The slit portion (1310) is a rectangular shape having a long side in the longitudinal direction of the electrode assembly (1200). A plurality of slits (1311) extending in the longitudinal direction of the electrode assembly (1200) are formed in the slit portion (1310). Each slit (1311) is arranged parallel to the thickness direction of the electrode assembly (1200). Foil tabs (1220, 1230) are fitted into the slits (1311).

[0077] The connecting portion (1320) is rectangular in shape and is connected to one side of the slit portion (1310). The connecting portion (1320) may include a support member (1321) and a current collecting projection (1322). The support member (1321) is a rectangular plate, is connected to one side of the slit portion (1310), and extends in the length direction of the electrode assembly (1200). The connecting portion (1320) is arranged on a portion of the electrode portion (1210) where no foil tabs (1220, 1230) are formed.

[0078] A current collector projection (1322) is positioned on the support member (1321). The current collector projection (1322) is connected to the through hole of the electrode terminal (1420, 1420a) to electrically connect the current collector plate (1300) and the electrode terminal (1420, 1420a).

[0079] The connecting portion (1320) may be formed integrally with the slit portion (1310). The connecting portion (1320) and the slit portion (1310) may have the same thickness.

[0080] Meanwhile, in another embodiment, as illustrated in FIG. 6A, the thickness (d1) of the connecting portion (1320) may be greater than the thickness (d2) of the slit portion (1310). The connecting portion (1320) is positioned on a portion of the electrode portion (1210) where the foil tabs (1220, 1230) are not formed. The slit portion (1310) is positioned on a portion of the electrode portion (1210) where the foil tabs are first welded and aligned. If the bottom surface of the slit portion (1310) is too close to the electrode portion (1210), the foil tabs may be damaged. Therefore, the connecting portion (1320) is formed thicker than the slit portion (1310), and the slit portion (1310) is spaced apart from the upper surface of the electrode portion by a predetermined distance so that the slit portion (1310) does not press the foil tabs (1220, 1230). By the slit portion (1310) being spaced apart from the electrode portion (1210) by a predetermined distance, the current collector plate (1300) can be stably supported on the electrode assembly (1200) and at the same time protect the foil tab.

[0081] Here, the slit portion (1310) and the connecting portion (1320) have the same height on the upper surface, but the connecting portion (1320) can be formed deeper on the lower surface. The height at which the foil tab is joined can be secured by the difference in thickness between the slit portion (1310) and the connecting portion (1320).

[0082] In another embodiment, the end-side thickness (d3) of the slit portion (1310) may be thicker than the inner thickness (d2) of the slit portion (1310) (FIG. 6b). By forming the end-side thickness (d3) of the slit portion (1310) thick, the portion of the slit portion (1310) arranged in the portion where the foil tab is formed may be spaced apart from the electrode portion (1210), while the collector plate (1300) may be stably connected on the electrode portion (1210). The end-side thickness (d3) of the slit portion (1310) may be equal to or smaller than the thickness (d1) of the connection portion (1320).

[0083] As illustrated in FIGS. 7a, 7b, and 7c, an insulating member (1330) may be placed at the bottom of the connecting portion (1320). The connecting portion (1320) is placed in an area where a foil tab is not formed, and the insulating member (1330) is placed on the bottom of the connecting portion (1320) to prevent short circuiting with the electrode plate.

[0084] In another embodiment, an insulating member may be placed on both the lower surface of the connection portion (1320) and the slit portion (1310) (Fig. 7b). In another embodiment, an insulating member may be placed only on the end surface of the connection portion (1320) and the slit portion (1310) (Fig. 7c).

[0085] The width of the current collector plate (1300) may be 0.8 to 1 times the width of the electrode portion (1210). The current collector plate (1300) may have a thickness of 0.5 to 3.0 mm. Since the present invention bends and welds the foil tab onto the current collector plate, the current collector plate can be formed thick.

[0086] Meanwhile, two collector plates (1300) may be provided. In order to electrically connect the electrode assembly (1200) and the electrode terminals (1420, 1420a), each collector plate (1300) may be made of the same material as the plurality of first foil tabs (1220) or the same material as the plurality of second foil tabs (1230). That is, each pair of collector plates (1300) may be formed of aluminum, copper, or nickel.

[0087] In the case of the collector plate (1300) connected to the positive terminal (1420), both the slit portion (1310) and the connection portion (1320) can be formed of aluminum.

[0088] In the case of the current collector plate (1300) connected to the negative terminal (1420a), the slit portion (1310) and the connection portion (1320) may be formed of different materials. The slit portion (1310) may be formed of the same material as the second foil tab (1230), and the current collector projection (1322) is formed of the same material as the negative terminal (1420a). That is, the current collector projection (1322) connected to the negative terminal (1420a) may be formed of an aluminum-based metal, and the slit portion (1310) connected to the foil tab (1230) may be formed of a copper-based metal.

[0089] Here, the support member (1321) may be formed of the same aluminum material as the current collector protrusion (1322), or may be formed of the same copper material as the slit portion (1310). When the support member (1321) is formed of the same material as the current collector protrusion (1322), the connecting portion (1320) may be formed integrally during molding.

[0090] When the support member (1321) is formed of a different material from the current collector protrusion (1322), the support member (1321) and the current collector protrusion (1322) can be joined by cold bonding. Cold bonding refers to a method in which the contact area is expanded by elongation between the joining materials due to a high pressure applied to the metal, thereby expanding the actual contact surface and joining them. An electrical connection with low contact resistance can be formed by cold bonding, which is the joining of materials within the actual contact surface.

[0091] The support member (1321) is formed integrally with the slit portion (1310) using Cu or Ni material, and a current collector projection (1322) made of Al material can be bonded to the support member (1321).

[0092] A pair of collector plates (1300) may be arranged symmetrically, but this is not limited to the arrangement, and the collector plates may be arranged in various ways as needed.

[0093]

[0094] FIG. 8 is a flowchart showing a method for manufacturing a secondary battery according to an embodiment of the present invention, FIGS. 9a and 9b are views showing a plurality of foil tabs formed on an electrode portion and side surfaces thereof in a secondary battery according to an embodiment of the present invention, FIGS. 10a and 10b are views showing a state in which a plurality of foil tabs are grouped into two or more foil tab groups in a secondary battery according to an embodiment of the present invention, FIG. 11 is a view showing a state in which a current collector plate is arranged on an electrode portion in a secondary battery according to an embodiment of the present invention, FIGS. 12a and 12b are views showing a state in which a plurality of foil tab groups and a current collector plate are welded in a secondary battery according to an embodiment of the present invention, FIG. 13 is a view showing a state in which a cover member is arranged at a portion in which a current collector plate and a foil tab group are welded in a secondary battery according to an embodiment of the present invention, and FIG. 14 is a view 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.

[0095] As illustrated in FIG. 8, 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). The electrode portion includes a plurality of unit electrode plates on which an active material is applied, and a separator that prevents short circuits between the plurality of unit electrode plates. The foil tabs are formed at one end of the plurality of unit electrode plates, and are not applied with an active material.

[0096] The electrode portion may be formed by positioning a separator between alternately arranged unit electrode plates. In one embodiment, the electrode portion is formed by alternately stacking unit electrode plates, separators, and unit electrode plates in that order. In another embodiment, the electrode portion may be formed by sequentially arranging unit electrode plates, separators, and unit electrode plates, and then winding them.

[0097] 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 plurality of first foil tabs (1220) are aligned with the first foil tabs (1220), and the plurality of second foil tabs (1230) are aligned with the second foil tabs (1230).

[0098] Next, a plurality of foil tabs are grouped into at least two foil tab groups, and each foil tab group is welded to itself (S1200). A plurality of first foil tabs (1220) may be arranged on one side of the electrode assembly, and a plurality of second foil tabs (1230) may be arranged on the other side of the electrode assembly (1200). Several to several tens of the plurality of first foil tabs (1220) are grouped together to form two or more foil tab groups. For example, one foil tab group may include at least five or more foil tabs. The plurality of first foil tabs (1220) are primarily welded to each other in the respective foil tab groups.

[0099] Similarly, the plurality of second foil tabs (1230) are grouped together in groups of several to several dozen second foil tabs to form two or more foil tab groups. For example, one foil tab group may include at least five foil tabs. The plurality of second foil tabs (1230) are also primarily welded together in groups of foil tabs.

[0100] A current collector plate (1300) is placed on the upper surface of the electrode portion (1210) (S1300). The connection portion (1320) of the current collector plate (1300) can be placed on a portion of the electrode portion (1210) where no foil tabs are formed. The slit portion (1310) of the current collector plate (1300) is positioned above a plurality of foil tab groups that are first welded on the electrode portion (1210). The current collector plate (1300) is positioned so that the first welded foil tab groups pass through each slit (1311). When the current collector plate (1300) is placed on the electrode portion (1210), the plurality of foil tab groups are fitted into the slits (1311).

[0101] The foil tab groups protruding from the upper portion of the slit (1311) of the collector plate (1300) are each bent toward the upper surface of the collector plate (1300) (S1400). When a plurality of first foil tab groups are inserted into a plurality of slits (1311) formed in the slit portion (1310), the plurality of foil tab groups protruding from the upper portion of the slit (1311) are each bent toward the upper surface of the slit portion (1310). For uniform welding, the plurality of foil tab groups can be bent in one direction, i.e., all in the same direction.

[0102] In the present invention, the foil tab is welded directly onto the current collector plate through a slit without bending the foil tab, eliminating the need for a long foil tab. Consequently, the present invention can reduce costs. Furthermore, since no bending space is required for the foil tab, the capacity of the secondary battery can be increased.

[0103] Furthermore, since the present invention positions the foil tabs (1220, 1230) on the collector plate (1300) and performs welding on the upper portion of the foil tabs, there is no concern about damaging the separator provided in the electrode portion (1210). When the collector plate (1300) is welded on the upper portion of the foil tabs (1220, 1230), the thickness of the collector plate must be thin in order to transfer heat to the foil tabs on the lower side, which leads to weakened durability. However, the present invention can secure the thickness of the collector plate by bending and welding a plurality of tabs on the collector plate, and can weld the foil tabs to the collector plate more efficiently.

[0104] A plurality of bent foil tabs and a collector plate (1300) are welded (S1500).

[0105] Welding can be performed on top of the foil tab group. Welding can be performed using methods such as ultrasonic welding or laser welding.

[0106] Meanwhile, as illustrated in FIG. 13, in one embodiment, after welding of a plurality of foil tab groups is completed, a cover member (1360) may be placed on the welded portion, i.e., the slit portion (1310). The cover member (1360) may cover at least a portion of the electrode assembly (1200) and the current collector plate (1300).

[0107] The cover member (1360) may include an insulating material. The cover member (1360) may be an insulating tape. The support member (1321) and the current collector protrusion (1322) may be exposed without being covered by the cover member (1360). The terminal (1420, 1420a) may be coupled to the current collector protrusion (1322). By covering the welding portion with the cover member (1360), the insulating structure of the cover plate (1400) may be further simplified.

[0108] 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. 14, after the collector projection (1322) 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 (1322) and the inner surface of the end of the through-hole can be welded.

[0109] 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 welding multiple foil tabs on the collector plate, and allows the foil tabs to be welded to the collector plate more efficiently.

[0110]

[0111] 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.

[0112]

[0113] 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 having an electrode part and a plurality of foil tabs formed at one end of the electrode part; and It includes a slit portion having a plurality of slits formed therein extending in the longitudinal direction of the electrode assembly, a connecting portion connected to one side of the slit portion and having a support member and a current collector projection, and a current collector plate disposed on the upper side of the electrode portion and welded to the plurality of foil tabs; A secondary battery wherein the above plurality of foil tabs are grouped into at least two foil tab groups, each of which passes through a slit of the current collector plate.

2. In paragraph 1, The above plurality of foil tab groups are each firstly welded, secondary batteries.

3. In paragraph 1, A secondary battery, wherein a plurality of foil tab groups protruding from the upper portion of the slit of the above-mentioned current collector plate are each bent toward the upper surface of the above-mentioned current collector plate.

4. In paragraph 1, A secondary battery, wherein the above one foil tab group includes at least five foil tabs.

5. In paragraph 1, A secondary battery in which the thickness of the connecting portion and the thickness of the slit portion in the above current collector plate are the same.

6. In paragraph 1, A secondary battery, wherein the thickness (d1) of the connecting portion in the above current collector plate is greater than the thickness (d2) of the slit portion.

7. In paragraph 1, A secondary battery, wherein the thickness (d3) of the end side of the slit portion in the above current collector plate is greater than the thickness (d2) of the inner side of the slit portion.

8. In paragraph 1, A secondary battery, wherein an insulating member is placed at the lower end of the connecting portion of the above-mentioned current collector plate.

9. In paragraph 1, A secondary battery, wherein an insulating member is arranged at the lower end of the connecting portion and the lower end of the slit portion in the above current collector plate.

10. In paragraph 1, A secondary battery, wherein the support member and the current collector projection in the above current collector plate are made of the same material.

11. In paragraph 1, A secondary battery, wherein the support member and the current collecting projection in the above current collecting plate are made of different materials.

12. A preparatory step in which an electrode assembly having an electrode part and a plurality of foil tabs formed on one end of the electrode part is prepared; A first welding step in which the above plurality of foil tabs are grouped into at least two foil tab groups and each foil tab group is welded to each other; A current collector plate arrangement step in which the current collector plate is arranged at one end of the electrode portion so that at least two of the first welded foil tab groups pass through the slits of the current collector plate; A bending step in which the foil tab group protruding from the upper portion of the slit of the current collector plate is each bent toward the upper surface of the current collector plate; and A method for manufacturing a secondary battery, comprising a second welding step in which a plurality of bent foil tab groups and the current collector plate are welded.

13. In paragraph 12, A secondary battery manufacturing method, wherein a plurality of foil tab groups protruding from the upper portion of the slit of the current collector plate in the above bending step are bent in one direction.

14. In paragraph 12, A method for manufacturing a secondary battery, wherein the thickness (d1) of the connecting portion in the above current collector plate is greater than the thickness (d2) of the slit portion.

15. In paragraph 12, A method for manufacturing a secondary battery, wherein an insulating part is placed at the lower end of the connecting part in the above-mentioned current collector plate.

16. In paragraph 12, A method for manufacturing a secondary battery, wherein an insulating member is placed at the lower end of the connecting portion and the lower end of the slit portion.

17. In paragraph 12, A method for manufacturing a secondary battery, wherein the support member and the current collecting projection in the above current collecting plate are made of the same material.

18. In paragraph 12, A method for manufacturing a secondary battery, wherein the support member and the current collecting projection in the above current collecting plate are made of different materials.

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

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

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