Secondary battery and manufacturing method therefor

Abstract

A secondary battery according to an aspect of the present invention comprises: a plurality of electrode assemblies stacked on each other, each electrode assembly including a stack in which a plurality of electrodes and a separator are alternately interposed, and a tab assembly including electrode tabs extending from at least one of the plurality of electrodes; a cap assembly including a cap covering one side of the plurality of electrode assemblies and a terminal coupled to the cap to be electrically connected to the outside; and a conductive member provided between the cap and the plurality of electrode assemblies to electrically connect the terminal and the electrodes. The conductive member may comprise: a tab-side coupling portion which extends in the stacking direction of the plurality of electrode assemblies and to which the tab assemblies of the plurality of electrode assemblies are coupled at predetermined intervals in the stacking direction; a terminal-side coupling portion coupled to the terminal; and a connection portion having a bent shape so as to connect the tab-side coupling portion and the terminal-side coupling portion.

Description

Secondary battery and method of manufacturing the same

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2025-0021968 dated February 20, 2025 and Korean Patent Application No. 10-2026-0029739 dated February 13, 2026, and all contents disclosed in the documents of said Korean patent applications are incorporated herein as part of this specification.

[0003] Technology field

[0004] The present invention relates to a secondary battery and a method for manufacturing the same, and more specifically, to a secondary battery capable of charging and discharging electrical energy and a method for manufacturing the same.

[0005] Although secondary batteries have been applied in small-scale fields such as mobile devices and laptop computers, research directions have recently expanded to medium and large-scale fields, and they are widely used in areas requiring high voltage and large capacity, such as Energy Storage Systems (ESS) and Electric Vehicles (EV). Secondary batteries can be provided in the form of battery cells consisting of an electrode assembly made of electrodes and a separator and a case that houses them. Depending on the shape of the case, such secondary batteries can be classified into pouch-type, prismatic, or cylindrical secondary batteries.

[0006] Recently, secondary batteries with a structure in which the electrode assembly is packaged by covering both sides of the electrode assembly with a pair of cap assemblies and wrapping the central part of the electrode assembly with an outer film have also been developed. The cap assemblies are equipped with terminals to conduct electricity to the outside of the electrode assemblies. In this case, to increase voltage or electrical capacity, multiple electrode assemblies are sometimes housed together in a single outer film. During the manufacturing process of such secondary batteries, the terminals of the cap assemblies must be connected to the tab assemblies provided on the multiple electrode assemblies. However, given the limited length of the tab assemblies, it has been very difficult to adjust the relative positions of the cap assemblies and electrode assemblies while connecting the terminals to the tab assemblies. In particular, there was a problem where the electrode assemblies or tab assemblies were prone to damage during this process. Consequently, there has been an urgent demand for the development of secondary batteries with improved assembly and manufacturing convenience.

[0007] The objective of the present invention is to provide a secondary battery with improved assembly and manufacturing convenience, and a method for manufacturing the same.

[0008] The problems of the present invention are not limited to those mentioned above, and other unmentioned problems will be clearly understood by a person skilled in the art to which the present invention pertains from the description below.

[0009] A secondary battery according to one aspect of the present invention may include: a plurality of electrode assemblies stacked together, each comprising a stack having a plurality of electrodes and a separator alternately interposed therein and a tab assembly consisting of electrode tabs extending from at least one of the plurality of electrodes; a cap assembly including a cap covering one side of the plurality of electrode assemblies and a terminal coupled to the cap and capable of conducting electricity with the outside; and a conductive member provided between the cap and the plurality of electrode assemblies to electrically connect the terminal and the electrode. The conductive member may include a tab-side coupling portion extending in the stacking direction of the plurality of electrode assemblies and to which the tab assembly of the plurality of electrode assemblies is coupled at predetermined intervals in the stacking direction; a terminal-side coupling portion coupled to the terminal; and a connecting portion having a bent shape to connect the tab-side coupling portion and the terminal-side coupling portion.

[0010] The terminal-side coupling portion may be extended in the stacking direction so as to be parallel to the tab-side coupling portion.

[0011] The above connecting part can connect the end of the terminal-side coupling part and the end of the tab-side coupling part.

[0012] The above connecting part may have a U-shape or a V-shape.

[0013] At this time, the terminal may include an inner portion located on the inner side of the cap and coupled to a terminal-side coupling portion; and an exposed portion extending from the inner portion and having at least one part exposed to the outside of the cap.

[0014] The terminal-side coupling portion extends in the stacking direction of the plurality of electrode assemblies, and the inner portion may extend in the stacking direction parallel to the terminal-side coupling portion.

[0015] The above exposed portion can be connected to the end of the above inner portion.

[0016] The above connection part is connected to the end of the terminal-side coupling part, and the above exposure part may be located adjacent to the above connection part.

[0017] The above-mentioned tab-side coupling portion includes an inward-facing surface facing the plurality of electrode assemblies; and an outward-facing surface facing the inward-facing surface, and one side of the tab assembly may be coupled on the outward-facing surface.

[0018] The above-mentioned tab-side coupling portion may be provided with a through hole through which the above-mentioned tab-side coupling portion passes.

[0019] The terminal-side coupling portion may be located between the tab-side coupling portion and the terminal.

[0020] The above secondary battery may further include an outer film that surrounds the other side of the at least one electrode assembly and is coupled to the cap.

[0021] A method for manufacturing a secondary battery according to another aspect of the present invention may include: preparing a plurality of electrode assemblies that are stacked together, each comprising a stack having a plurality of electrodes and a separator alternately interposed therein and a tab assembly consisting of electrode tabs extending from at least one of the plurality of electrodes; preparing a cap assembly comprising a cap and a terminal coupled to the cap; coupling the tab assembly of the plurality of electrode assemblies to a tab-side coupling portion of a first type conductive member at predetermined intervals in the stacking direction of the plurality of electrode assemblies; coupling the terminal-side coupling portion of the first type conductive member to the terminal; and forming a second type conductive member by bending a connecting portion of the first type conductive member so that the cap assembly moves toward the plurality of electrode assemblies.

[0022] The distance between the tab-side coupling portion and the terminal-side coupling portion of the first type of conductive member may be greater than the distance between the tab-side coupling portion and the terminal-side coupling portion of the second type of conductive member.

[0023] The connecting portion of the first type of conductive member may have an L-shape.

[0024] The connecting portion of the second type conductive member may have a U-shape or a V-shape.

[0025] The method for manufacturing the secondary battery described above may further include the step of surrounding the plurality of electrode assemblies with an outer film; and the step of combining the outer film with the cap.

[0026] The above-mentioned tab-side coupling member includes an inward-facing surface and an outward-facing surface opposite to the inward-facing surface, and in the step of coupling the above-mentioned tab-side coupling member and the tab assembly, the above-mentioned tab-side coupling member is arranged so that the inward-facing surface faces the plurality of electrode assemblies, and one side of the above-mentioned tab-side coupling member can be coupled to the outward-facing surface.

[0027] The tab-side coupling portion and the terminal-side coupling portion of the first type of conductive member can be extended in different directions.

[0028] According to one aspect of the present invention, a conductive member is provided between a cap assembly and an electrode assembly, so that the relative positions of the electrode assembly and the cap assembly can be adjusted by bending the connecting portion of the conductive member after the electrode assembly and the terminal are each coupled with the conductive member, thereby significantly improving assembly and manufacturing convenience.

[0029] The effects of the present invention are not limited to the effects described above, and unmentioned effects will be clearly understood by those skilled in the art from this specification and the attached drawings.

[0030] FIG. 1 is a perspective view of a secondary battery according to one embodiment of the present invention.

[0031] Figure 2 is a cross-sectional view according to II of Figure 1.

[0032] Figure 3 is an enlarged view of part A of Figure 2.

[0033] FIG. 4 is a perspective view of a secondary battery according to another embodiment of the present invention.

[0034] Figure 5 is a cross-sectional view according to II-II of Figure 4.

[0035] FIG. 6 is a flowchart of a method for manufacturing a secondary battery according to one embodiment of the present invention.

[0036] FIG. 7 is a diagram illustrating steps S30 to S50 of FIG. 6.

[0037] Figure 8 is a diagram illustrating step S60 of Figure 6.

[0038] Preferred embodiments of the present invention are described in detail so that those skilled in the knowledge can easily implement them. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0039] In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification.

[0040] In addition, terms or words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0041] FIG. 1 is a perspective view of a secondary battery according to one embodiment of the present invention. FIG. 2 is a cross-sectional view according to II of FIG. 1. FIG. 3 is an enlarged view of portion A of FIG. 2. In this case, the electrode assembly is not shown in cross-section in FIG. 2 and FIG. 3.

[0042] FIGS. 1 to 3 disclose a secondary battery (1) according to an embodiment of the present invention. The secondary battery (1) according to an embodiment of the present invention may be a device for charging and discharging electrical energy. In the secondary battery (1) according to the present embodiment, an electrode assembly (10) responsible for charging and discharging functions may be packaged with a cap assembly (20) and an outer film (40).

[0043] At this time, the secondary battery (1) may be a secondary battery in which the assembly and manufacturing convenience of the manufacturing process are greatly improved by providing a conductive member (30) inside the cap assembly (20) and the outer film (40). Below, each component of the secondary battery according to one embodiment of the present invention will be described in detail.

[0044] Referring to FIGS. 1 to 3, a secondary battery (1) according to one embodiment of the present invention may include an electrode assembly (10). As described above, the electrode assembly (10) may be a component responsible for charging and discharging functions. To this end, the electrode assembly (10) may include a laminate (12) in which a plurality of electrodes and a separator are alternately interposed. Some of the plurality of electrodes may be positive electrodes, and the remainder may be negative electrodes. The separator may be replaced with an all-solid material, etc.

[0045] The type of electrode assembly (10) can be appropriately selected, such as a stack type, a jelly roll type, or a stack and folding type. That is, the laminate (12) is not limited to the electrode and the separator being formed in a stacked manner.

[0046] In this embodiment, the electrode assembly (10) may be provided with a tap assembly (14). The tap assembly (14) may be configured to conduct electricity to the outside of the electrode assembly (10). The tap assembly (14) may be an assembly composed of electrode taps extending from each of a plurality of electrodes. The tap assembly (14) may extend from one side of the stack (12). As illustrated, the tap assembly (14) may extend forward (in the positive direction of the X-axis) from the stack (12). However, the direction in which the tap assembly (14) extends is not particularly limited.

[0047] At this time, although not specifically illustrated, the electrode assembly (10) may include a plurality of tab assemblies (14). Some of the plurality of tab assemblies (14) may consist of electrode tabs extending from an anode electrode, and the remainder may consist of electrode tabs extending from a cathode electrode.

[0048] Meanwhile, in the present embodiment, the electrode assembly (10) may be composed of two or more (i.e., multiple). In other words, the secondary battery (1) may include a plurality of electrode assemblies (10). Each electrode assembly (10) may include a laminate (12) and at least one tab assembly (14). Through this, the electrical capacity and / or voltage of the secondary battery (1) may be increased.

[0049] At this time, a plurality of electrode assemblies (10) may be arranged in a predetermined manner. As illustrated, in this embodiment, a plurality of electrode assemblies (10) may be stacked on top of each other. The direction in which the plurality of electrode assemblies (10) are stacked (Z-axis direction) may be the up-down direction. Also, in this embodiment, a plurality of tab assemblies (14) may be arranged in parallel along the stacking direction (Z-axis direction) of the plurality of electrode assemblies (10). At this time, the plurality of tab assemblies (14) arranged in parallel may have the same polarity (positive or negative). However, the shape or direction in which the plurality of electrode assemblies (10) and / or tab assemblies (14) are arranged may be appropriately modified as needed.

[0050] Referring to FIGS. 1 and 2, a secondary battery (1) according to one embodiment of the present invention may include a cap assembly (20). The cap assembly (20) may be configured to package an electrode assembly (10) together with an outer film (40) described later. As a result, the electrode assembly (10) can be contained together with an electrolyte and isolated from the outside.

[0051] In this embodiment, the cap assembly (20) may be composed of a pair. The pair of cap assemblies (20) may be placed at each end of the electrode assembly (10). Additionally, an outer film (40) may surround the electrode assembly (10) between the pair of cap assemblies (20). However, if necessary, the cap assembly (20) may be composed of only one.

[0052] Meanwhile, in this embodiment, the cap assembly (20) may include a cap (22). The cap (22) may be configured to cover one side of the electrode assembly (10). In this embodiment, the cap (22) may be positioned in front of the electrode assembly (10) (in the positive direction of the X-axis) to cover it.

[0053] As described, the cap (22) may include a cover portion (23). The cover portion (23) may have a rectangular plate shape that covers the longitudinal end (positive direction of the X-axis) of the electrode assembly (10). The cover portion (23) may be made of a material having a certain rigidity. For example, the cover portion (23) may be made of plastic or metal, but is not limited thereto.

[0054] In this embodiment, the cap (22) may include an extension portion (24). The extension portion (24) may be a portion extending from the edge portion of the cover portion (23) toward the electrode assembly (10). The extension portion (24) may function as a base for joining the cap assembly (20) and the outer film (40). That is, the outer film (40) may be joined to the extension portion (24). To this end, an adhesive may be provided on the outer surface of the extension portion (24), or a resin layer that can be melted by heat or pressure may be provided. However, the structure of the extension portion (24) may be modified according to the method or structure in which the cap assembly (20) and the outer film (40) are joined.

[0055] In this embodiment, the extension portion (24) may be provided along the edge of the cover portion (23). When viewed in the longitudinal direction (X-axis direction) of the electrode assembly (10), the extension portion (24) may have a closed ring shape that surrounds the cover portion (23) along the edge. However, the specific shape or structure of the cap (22) is not particularly limited as long as it can cover one side of the electrode assembly (10).

[0056] In this embodiment, the cap assembly (20) may include a terminal (26). The terminal (26) may be coupled to the cap (22). The terminal (26) may penetrate the cap (22). The terminal (26) may be made of a conductive material. Through this, the terminal (26) can conduct electricity to the outside of the electrode assembly (10).

[0057] At this time, the terminal (26) may include an inner portion (27). The inner portion (27) may be a part located on the inner side of the cap (22). The inner portion (27) may be a configuration that is directly coupled with the conductive member (30) described later. Here, the inner side of the cap (22) may refer to the rear portion (negative direction of the X-axis) of the cap (22) facing the electrode assembly (10) from the cap (22). More specifically, the inner portion (27) may be located between the cover portion (23) and the electrode assembly (10). In this embodiment, the inner portion (27) may extend in the direction (Z-axis direction) in which a plurality of electrode assemblies (10) are stacked. This means that the inner portion (27) extends not only completely parallel to the direction (Z-axis direction) in which a plurality of electrode assemblies (10) are stacked, but also includes cases where it extends somewhat obliquely. Through this, a sufficient area can be secured where the inner part (27) and the terminal-side coupling part (34) of the conductive member (30) described later are coupled to each other.

[0058] Meanwhile, in this embodiment, the terminal (26) may include an exposed portion (28). The exposed portion (28) may extend from the inner portion (27) toward the outside of the cap (22). Here, "extended" does not mean that the longitudinal direction of the inner portion (27) and the longitudinal direction of the exposed portion (28) are parallel. The exposed portion (28) may extend parallel to the longitudinal direction (X-axis direction) of the electrode assembly (10). The exposed portion (28) may be formed integrally with the inner portion (27), but is not limited thereto.

[0059] The exposed portion (28) can penetrate the cap (22). At this time, at least a portion of the exposed portion (28) (e.g., an end) may be exposed to the outside of the cap (22). Through this, the exposed portion (28) can be directly connected to an external load or power source. Here, the outside of the cap (22) may refer to a portion that is in a direction away from the electrode assembly (10) with respect to the cap (22) (positive direction of the X-axis).

[0060] In this embodiment, the exposed portion (28) may extend from the inner portion (27). More specifically, the exposed portion (28) may extend from one side of the inner portion (27) in the extension direction (Z-axis direction). Alternatively, the exposed portion (28) may extend from one end of the inner portion (27). In this case, the exposed portion (28) may extend from the end adjacent to the connecting portion (36) of the conductive member (30) described later, among the two ends of the inner portion (27). This may be intended to improve the structural stability of the secondary battery (1).

[0061] Referring to FIGS. 1 and 2, the exposed portion (28) of the terminal (26) may have a shape that extends in the width direction (Y-axis direction) of the secondary battery (1). However, this is exemplary, and the shape of the exposed portion (28) may be appropriately selected as needed.

[0062] Meanwhile, in this embodiment, the terminal (26) is shown to include one exposed portion (28). However, if necessary, the exposed portion (28) may be composed of two or more and arranged in a predetermined manner. For example, the exposed portion (28) may be composed of a pair and provided at each end of the inner portion (27).

[0063] Referring again to FIGS. 1 and FIGS. 2, a secondary battery (1) according to one embodiment of the present invention may include an outer film (40). The outer film (40) may be configured to package an electrode assembly (10) together with a cap assembly (20). At this time, the outer film (40) may have a certain flexibility. The outer film (40) may be provided as a film having a multilayer structure.

[0064] More specifically, the exterior film (40) may include a surface protection layer made of a polymer provided on the outermost layer, a sealant layer made of a polymer provided on the innermost layer, and a gas barrier layer made of a metal interposed between the surface protection layer and the sealant layer. Here, the polymer may include polyethylene terephthalate and / or polypropylene, and the metal may include iron (Fe), chromium (Cr), manganese (Mn), nickel (Ni) and / or aluminum. However, the structure of the exterior film and the material forming it may be appropriately modified as needed.

[0065] In this embodiment, the outer film (40) can surround the electrode assembly (10) together with a pair of cap assemblies (20). Hereinafter, the portion where the outer film (40) surrounds the electrode assembly (10) is referred to as the periphery portion of the electrode assembly (10). At this time, one edge of the secondary outer film (40) may be connected to the cap assembly (20) located in the front (positive direction of the X-axis) of the pair of cap assemblies (20), and the other edge may be connected to the cap assembly (20) located in the rear (negative direction of the X-axis).

[0066] As a result, the electrode assembly (10) can be packaged by the cap assembly (20) and the outer film (40) and isolated from the outside. The electrode assembly (10) can be protected from external shock or contamination by the cap assembly (20) and the outer film (40). In particular, in the secondary battery (1) according to the present embodiment, since the front and rear of the electrode assembly (10) are protected by the cap assembly (20) having a certain rigidity, it can have stronger resistance to external shock or contamination compared to a general pouch-type secondary battery manufactured by sealing pouch films together.

[0067] In addition, in the secondary battery (1) according to the present embodiment, the electrode assembly (10) is wrapped with an outer film (40) having a flexible periphery portion, so damage caused by deformation of the electrode assembly (10) can be minimized. Furthermore, if the internal pressure of the secondary battery (1) rises excessively, a part of the outer film (40) may break and the internal gas may be released, so the stability of the secondary battery (1) can also be increased.

[0068] For example, during the charging and discharging process, the electrode assembly (10) may expand (i.e., swelling phenomenon), and the outer film (40) may bend or stretch together in response to the volume change of the electrode assembly (10) to accommodate the deformation of the electrode assembly (10). As a result, local pressure or stress between the electrode assembly (10) and the outer film (40) can be relieved, thereby minimizing damage caused by the deformation of the electrode assembly (10). In contrast, in conventional prismatic secondary batteries, the case does not deform even when the electrode assembly expands, so significant damage may occur to the electrode assembly as the electrode assembly and the case interfere with each other.

[0069] Meanwhile, referring to FIGS. 2 and FIGS. 3, a secondary battery (1) according to one embodiment of the present invention may include a conductive member (30). In this embodiment, the conductive member (30) may be configured to conduct current between a terminal (26) and a tab assembly (14). The conductive member (30) may be made of a conductive material. The conductive member (30) may be named a bus bar.

[0070] In this embodiment, the conductive member (30) may be configured to improve the assembly and manufacturing convenience of the secondary battery (1). To this end, the conductive member (30) may be made of a film or a metal piece having a predetermined thickness. It may be preferable for the conductive member (30) to have a degree of rigidity such that it can be bent by an external force applied during the manufacturing process.

[0071] The conductive member (30) may include a tap-side coupling part (32) coupled to a plurality of tap assemblies (14), a terminal-side coupling part (34) coupled to a terminal (26) of a cap assembly (20), and a connecting part (36) connecting the tap-side coupling part (32) and the terminal-side coupling part (34).

[0072] In this embodiment, the tab-side coupling portion (32) may extend in the direction in which a plurality of electrode assemblies (10) are stacked (Z-axis direction). As a result, a sufficient area may be secured for a plurality of tab assemblies (14) to be coupled. In this embodiment, all tab assemblies (14) that are electrically connected to the outside through the terminal (26) may be coupled to the tab-side coupling portion (32). The tab assemblies (14) may be arranged in the stacking direction (Z-axis direction) and each may be coupled along the extension direction of the tab-side coupling portion (32).

[0073] In other words, the tab assembly (14) of the plurality of electrode assemblies (10) can be coupled to the tab-side coupling portion (32) at predetermined intervals in the stacking direction (Z-axis direction) of the plurality of electrode assemblies (10). More specifically, the tab assembly (14) of the plurality of electrode assemblies (10) can be coupled to the tab-side coupling portion (32) at predetermined intervals.

[0074] Meanwhile, in this embodiment, the tap-side coupling portion (32) may include an inward-facing surface (32a) and an outward-facing surface (32b). The inward-facing surface (32a) may be a surface facing the electrode assembly (10), and the outward-facing surface (32b) may be a surface facing the inward-facing surface (32a). Hereinafter, the direction of the gap (X-axis direction) formed by the outward-facing surface (32b) and the inward-facing surface (32a) is referred to as the thickness direction of the tap-side coupling portion (32).

[0075] At this time, one side of the tap assembly (14) may be coupled to the outward surface (32b) of the tap side coupling part (32). To this end, the tap side coupling part (32) may be provided with a through hole (33) in the thickness direction. The tap assembly (14) may pass through the through hole (33). The portion of the tap assembly (14) exposed to the front (positive direction of the X-axis) of the through hole (33) may be coupled to the outward surface (32b).

[0076] At this time, the through holes (33) may be composed of multiple holes. The number of through holes (33) may correspond to the number of tap assemblies (14). Multiple through holes (33) may be arranged in an up-and-down direction (Z-axis direction) so as to be parallel to multiple tap assemblies (14). Each of the multiple tap assemblies (14) may pass through the multiple through holes (33).

[0077] As such, in this embodiment, since a through hole (33) is provided in the tap-side coupling portion (32) of the conductive member (30), the tap assembly (14) can be coupled on the outward surface (32b). Therefore, the operator can combine the tap-side coupling portion (32) and the tap assembly (14) more easily than when combining the tap assembly (14) on the inward surface (32a).

[0078] This is because, although it is difficult for a specific tool (e.g., a welding machine) for joining them to enter the narrow gap between the inner surface (32a) and the electrode assembly (10), sufficient space can be secured on the outer surface (32b) for the tool to work. Through this, the assembly and manufacturing convenience of the secondary battery (1) can be improved. This will be described in detail later together with a method for manufacturing a secondary battery according to an embodiment of the present invention.

[0079] In this embodiment, the terminal-side coupling portion (34) may extend in the stacking direction (Z-axis direction) of the electrode assembly (10) parallel to the tab-side coupling portion (32). Through this, the terminal-side coupling portion (34) may be coupled to the inner portion (27) of the terminal (26) over a large area. This terminal-side coupling portion (34) may be parallel to the tab-side coupling portion (32). Accordingly, the conductive member (30) may be provided in a structure that is as compact as possible, and the energy density of the secondary battery (1) may be improved.

[0080] Meanwhile, in this embodiment, the connecting part (36) may have a bent shape to connect one end of the tap-side connecting part (32) and one end of the terminal-side connecting part (34). At this time, the one end of the tap-side connecting part (32) and the terminal-side connecting part (34) connected by the connecting part (36) may refer to the lower end (negative direction of the Z-axis). Also, the bent shape can be understood to include not only a U-shaped curved shape as illustrated, but also a V-shaped bent shape.

[0081] This connecting part (36) can be formed as a part of the conductive member (30) is deformed into a bent shape during the process of bringing the tap-side connecting part (32) and the terminal-side connecting part (34) into close contact after the tap-side connecting part (32) and the tap assembly (14) are connected and the terminal-side connecting part (34) and the terminal (26) are connected.

[0082] Meanwhile, the connecting portion (36) of the conductive member (30) and the exposed portion (28) of the terminal (26) may be arranged adjacently. In other words, the connecting portion (36) may come into contact with the exposed portion (28) (or, the part where the exposed portion (28) extends from the inner portion (27), i.e., the end of the inner portion (27). Since the connecting portion (36) is the part where deformation of the conductive member (30) occurs primarily during the manufacturing process of the secondary battery (1), the structural stability of the secondary battery (1) can be improved by arranging the connecting portion (36) and the exposed portion (28) as adjacently as possible. This is because the exposed portion (28) can support and reinforce the connecting portion (36).

[0083] As previously explained, in a secondary battery (1) according to one embodiment of the present invention, a conductive member (30) with a curved shape is provided between a cap assembly (20) and an electrode assembly (10). Therefore, after the coupling process between the conductive member (30) and the terminal (26) of the cap assembly (20) and the coupling process between the conductive member (30) and the tab assembly (14) of the electrode assembly (10) are performed, the conductive member (30) can be bent and the cap assembly (20) can be moved in close contact toward the electrode assembly (10), and this process can be performed sequentially. As a result, the assembly and manufacturing convenience of the secondary battery (1) can be significantly improved. Specific details regarding this will be explained in detail together with the manufacturing method of the secondary battery according to one embodiment of the present invention.

[0084] Hereinafter, a method for manufacturing a secondary battery according to one embodiment of the present invention (hereinafter referred to as the "manufacturing method") is described. The manufacturing method according to one embodiment of the present invention may be a method for manufacturing a secondary battery according to one embodiment of the present invention as previously described. In this case, the manufacturing method according to one embodiment of the present invention may be a method with significantly improved manufacturing convenience.

[0085] FIG. 4 is a perspective view of a secondary battery according to another embodiment of the present invention, and FIG. 5 is a cross-sectional view according to II-II of FIG. 4.

[0086] Hereinafter, the content described above will be used by reference, but the differences from the previously described embodiments will be explained in detail.

[0087] The exposed portion (28') of the terminal (26') according to the present embodiment may be circular instead of extending in a specific direction. More specifically, when viewed from the length direction (X-axis direction) of the secondary battery (1), the shape of the exposed portion (28') may be circular. However, it is not limited thereto, and the shape of the exposed portion (28') may be designed to be various shapes such as elliptical or polygonal.

[0088] In addition, unlike the previously described embodiment, the exposed portion (28') may extend (protrude) from a portion other than the end of the inner portion (27). For example, the exposed portion (28') may extend (protrude) from the central portion of the inner portion (27). This provides the advantage that the position and size of the exposed portion (28') of the terminal (26) may not be limited.

[0089] FIG. 6 is a flowchart of a method for manufacturing a secondary battery according to an embodiment of the present invention. FIG. 7 is a diagram for explaining steps S30 to S50 of FIG. 6. FIG. 8 is a diagram for explaining step S60 of FIG. 6. In FIG. 7 and FIG. 8, the electrode assembly is not shown in cross-section. Also, in FIG. 7 and FIG. 8, the terminal (28) is shown based on an embodiment, but is not limited thereto.

[0090] Referring to FIGS. 1 to 6, in a manufacturing method according to one embodiment of the present invention, an electrode assembly (10) is prepared (S10) and a cap assembly (20) is prepared (S20). At this time, the order of steps S10 and S20 is not particularly limited. The electrode assembly (10) and the cap assembly (20) may be configured in the same way as the electrode assembly and the cap assembly of the secondary battery (1) according to one embodiment of the present invention.

[0091] Referring to FIGS. 6 and 7, in a manufacturing method according to one embodiment of the present invention, an electrode assembly (10) and a cap assembly (20) are prepared (S10, S20), a tab-side coupling portion (32') of a first type conductive member (30') is coupled with a plurality of tab assemblies (14) (S30), and a terminal-side coupling portion (34') of a first type conductive member (30') is coupled with a terminal (26) of a cap assembly (20) (S40). At this time, the order of steps S30 and S40 is not particularly limited.

[0092] The first type conductive member (30') may refer to the previous state of the conductive member (30) described above. That is, during the manufacturing process, the first type conductive member (30') may become the second type conductive member (30), and the conductive member (30) described above refers to this second type conductive member (30).

[0093] The first type conductive member (30') may include a tap-side coupling portion (32'), a terminal-side coupling portion (34'), and a connecting portion (36') connecting the tap-side coupling portion (32') and the terminal-side coupling portion (34'). Each component of the first type conductive member (30') can be appropriately adapted from the description of the preceding conductive member (30).

[0094] At this time, in this embodiment, the distance between the tap-side coupling portion (32') and the terminal-side coupling portion (34') of the first type conductive member (30') may be greater than the distance between the tap-side coupling portion (32) and the terminal-side coupling portion (34) of the second type conductive member (30). Here, the distance between the tap-side coupling portion and the terminal-side coupling portion may refer to the distance between one end of the tap-side coupling portion and one end of the terminal-side coupling portion. At this time, the one end of the tap-side coupling portion and the terminal-side coupling portion may refer to an end located on the opposite side of the connection portion. In other words, the tap-side coupling portion (32') and the terminal-side coupling portion (34') of the first type conductive member (30') may be extended in different directions. Here, the fact that the two components are extended in different directions may mean that the two components are not parallel or parallel to each other. That is, the tab-side coupling portion (32') and the terminal-side coupling portion (34') of the first type of conductive member (30') may be spread apart to form a predetermined angle with respect to each other. The angle may be a right angle or an obtuse angle, but is not limited thereto.

[0095] As such, in the manufacturing method according to the present embodiment, since sufficient space is secured between the tab-side coupling part (32') and the terminal-side coupling part (32') for the worker to utilize, the worker can easily perform the coupling process of the conductive member (30) and the terminal (26) (i.e., step S40) and the coupling process of the conductive member (30) and the tab assembly (14) (i.e., step S30). Through this, the manufacturing convenience of the present manufacturing method can be greatly improved.

[0096] In particular, at this time, in step S30 of the manufacturing method according to one embodiment of the present invention, one side of the tap assembly (14) may be coupled to the outward surface (32b) of the tap side coupling portion (32'). To this end, the tap assembly (14) may penetrate the through hole (33) of the tap side coupling portion (32'). Accordingly, the operator can easily perform the coupling process of the two components by utilizing the wide space on the outward surface (32b) rather than the narrow space between the tap side coupling portion (32') and the electrode assembly (10).

[0097] Referring to FIGS. 6 to 8, in a manufacturing method according to one embodiment of the present invention, a conductive member (30), a terminal (26), and a tab assembly (14) are combined (S30, S40), and a connecting portion (36') of a first type conductive member (30') is bent to form a second type conductive member (30) (S50).

[0098] More specifically, in this embodiment, the connecting portion (36') of the first type conductive member (30') may have an L-shape. As previously explained, an L-shape may mean a state in which the tab-side connecting portion (32') and the terminal-side connecting portion (34'), which are connected to each other by the connecting portion (36'), are spread apart to form a predetermined angle with each other.

[0099] The connecting portion (36) of the second type conductive member (30) may have a U-shape (or a V-shape). As a result, the tab-side connecting portion (32) and the terminal-side connecting portion (34) can be in close contact with each other. That is, the cap assembly (20) and the electrode assembly (10) can be in close contact. Therefore, the energy density of the secondary battery can be improved.

[0100] Next, in a manufacturing method according to one embodiment of the present invention, a first type conductive member (30') is bent to form a second type conductive member (30) (S50), the remaining part of the electrode assembly (10) is wrapped with an outer film (40) (S60), and the outer film (40) and the cap assembly (20) are combined (S70). As a result, the electrode assembly (10) can be packaged by the cap assembly (20) and the outer film (40) and isolated from the outside.

[0101] As previously explained, in the manufacturing method according to one embodiment of the present invention, step S50 is performed after steps S30 and S40 are performed, thereby enabling the coupling between the conductive member (30) and the terminal (26) and the coupling between the conductive member (30) and the tab assembly (14) to be performed easily, while also enabling the manufacture of a secondary battery with improved energy density and structural stability.

[0102] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0103] [Explanation of the symbol]

[0104] 1: Secondary battery 10: Electrode assembly

[0105] 12: Laminate 14: Tab assembly

[0106] 20: Cap assembly 22: Cap

[0107] 26: Terminal 30: (Type 2) Conductive member

[0108] 30': Type 1 conductive member 32: Tab-side joint

[0109] 33: Through hole 34: Terminal-side connection part

[0110] 36: Connection part 40: Exterior film

Claims

1. A plurality of electrode assemblies stacked together, each comprising a laminate having a plurality of electrodes and a separator alternately interposed therein, and a tab assembly consisting of electrode tabs extending from at least one of the plurality of electrodes; A cap assembly comprising a cap covering one side of the plurality of electrode assemblies and a terminal coupled to the cap and capable of conducting electricity with the outside; and It includes a conductive member provided between the above cap and the above plurality of electrode assemblies to electrically connect the terminal and the electrode, The above conductive member is, A tab-side coupling portion extending in the stacking direction of the plurality of electrode assemblies, wherein the tab assembly of the plurality of electrode assemblies is coupled at predetermined intervals in the stacking direction; A terminal-side coupling portion coupled to the above terminal; and A secondary battery comprising a connecting portion having a bent shape to connect the tab-side connecting portion and the terminal-side connecting portion.

2. In Paragraph 1, The above terminal-side coupling part is, A secondary battery extending in the stacking direction so as to be parallel to the above tab-side coupling portion.

3. In Paragraph 2, The above connecting part is, A secondary battery connecting the end of the terminal-side coupling portion and the end of the tab-side coupling portion.

4. In Paragraph 2, The above connecting part is, A secondary battery having a U-shaped or V-shaped form.

5. In Paragraph 1, The above terminal is, An inner part located on the inner side of the above cap and coupled to the terminal side coupling part; and A secondary battery comprising an exposed portion extending from the inner portion and having at least one portion exposed to the outside of the cap.

6. In Paragraph 5, The above terminal-side coupling part is, Extending in the stacking direction of the plurality of electrode assemblies above, and The above inner part is, A secondary battery extending in the stacking direction so as to be parallel to the terminal-side coupling portion.

7. In Paragraph 6, The above exposed portion is, A secondary battery connected to the end of the inner part above.

8. In Paragraph 7, The above connecting part is, Connected to the end of the terminal-side coupling part above, and The above exposed portion is, A secondary battery located adjacent to the above-mentioned connection.

9. In Paragraph 1, The above tab-side coupling part is, An inward surface facing the plurality of electrode assemblies; and It includes an outward surface facing the inward surface above, and One side of the above-mentioned tab assembly is, A secondary battery coupled to the above-mentioned outward surface.

10. In Paragraph 9, In the above tab-side coupling portion, A secondary battery having a through hole through which the above-mentioned tab-side coupling portion passes.

11. In Paragraph 1, The above terminal-side coupling part is, A secondary battery located between the above-mentioned tab-side coupling portion and the above-mentioned terminal.

12. In Paragraph 1, A secondary battery further comprising an outer film that surrounds the other side of at least one electrode assembly and is coupled to the cap.

13. A step of preparing a plurality of electrode assemblies that are stacked together, each comprising a stack having a plurality of electrodes and a separator alternately interposed therein and a tab assembly consisting of electrode tabs extending from at least one of the plurality of electrodes; A step of preparing a cap assembly comprising a cap and a terminal coupled to the cap; A step of coupling the tab assembly of the plurality of electrode assemblies to the tab-side coupling portion of a first type conductive member at predetermined intervals in the stacking direction of the plurality of electrode assemblies; A step of connecting the terminal-side coupling portion of the first type conductive member and the terminal; and A method for manufacturing a secondary battery, comprising the step of forming a second type conductive member by bending the connecting portion of the first type conductive member so that the cap assembly is moved toward the plurality of electrode assemblies.

14. In Paragraph 13, The distance between the tab-side coupling portion and the terminal-side coupling portion of the first type of conductive member is, A method for manufacturing a secondary battery, wherein the distance between the tab-side coupling portion and the terminal-side coupling portion of the second type conductive member is greater than the distance between them.

15. In Paragraph 14, The connecting portion of the above-mentioned first type conductive member is, A method for manufacturing a secondary battery having an L-shape.

16. In Paragraph 13, The connecting portion of the above-mentioned second type conductive member is, A method for manufacturing a secondary battery having a U-shape or V-shape.

17. In Paragraph 13, A step of surrounding the plurality of electrode assemblies with an outer film; and A method for manufacturing a secondary battery, further comprising the step of combining the outer film and the cap.

18. In Paragraph 13, The above tab-side coupling part is, Inward face; and It includes an outward surface facing the inward surface above, and A method for manufacturing a secondary battery, wherein in the step of combining the above-mentioned tab-side coupling portion and the above-mentioned tab assembly, the above-mentioned tab-side coupling portion is arranged such that the inward surface faces the plurality of electrode assemblies, and one side of the above-mentioned tab-side coupling portion is coupled to the outward surface.

19. In Paragraph 13, The tab-side coupling portion and the terminal-side coupling portion of the first type of conductive member are, A method for manufacturing a secondary battery, extended in different directions.

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