Secondary battery and method for manufacturing same

Abstract

The invention provides a secondary battery and a manufacturing method thereof. The present disclosure relates to a secondary battery capable of increasing an internal space utilization rate of a case and improving energy density. For example, disclosed is a secondary battery including: an electrode assembly including a current collector tab having a bent portion formed by bending the current collector tab at least once, the current collector tab having an end portion bonded to the bent portion and protruding from the electrode assembly; a case including a main body formed with an accommodating portion configured to accommodate the electrode assembly, and a cover configured to cover the main body; an electrode lead electrically connected to an end portion of the current collector tab and led out from the case; and an adhesive member formed in a region formed by the bent portion of the current collector tab.

Description

Technical Field

[0001] The present disclosure relates to a secondary battery and a method of manufacturing the same. Background Art

[0002] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries that can be charged and discharged. Low-capacity secondary batteries are used in small portable electronic devices (such as smartphones, feature phones, tablets, laptops, digital cameras, and video cameras), while large-capacity secondary batteries are widely used as power sources for driving motors and storing electricity in hybrid vehicles and electric vehicles.

[0003] These secondary batteries may include an electrode assembly consisting of a negative electrode and a positive electrode, a housing that houses the electrode assembly, and terminals connected to the electrode assembly. Depending on the shape of the secondary battery, secondary batteries can be categorized as round, prismatic, or pouch-type. Among these, pouch-type secondary batteries can be easily deformed into various shapes and can be formed from a lightweight pouch outer material.

[0004] The above information disclosed in the background of the present disclosure is only for enhancement of understanding of the background of the present disclosure and therefore may include information that does not constitute relevant art. Summary of the invention

[0005] The present disclosure provides a secondary battery capable of improving a bent shape of an electrode lead and improving internal space utilization and energy density of a case.

[0006] A secondary battery according to the present disclosure may include: an electrode assembly including a current collector tab having a bent portion formed by bending the current collector tab at least once, the current collector tab having an end portion coupled to the bent portion and protruding from the electrode assembly; a case including a main body formed with a receiving portion configured to receive the electrode assembly and a cover configured to cover the main body; an electrode lead electrically connected to the end portion of the current collector tab and led out from the case; and a bonding member formed in a region formed by the bent portion of the current collector tab.

[0007] In some embodiments, an adhesive member may be formed on an inner surface of the bent portion.

[0008] In some embodiments, the bonding member may fix the shape of the curved portion.

[0009] In some embodiments, the region formed by the bent portion may be a concave region, and the adhesive member may be received in the concave region formed when the bent portion is bent.

[0010] In some embodiments, the adhesive member may terminate before the end portion where the current collector tab is coupled to the electrode lead.

[0011] In some embodiments, the adhesive member may be formed to fill the inside of the bent portion and formed under the end of the current collector tab.

[0012] In some embodiments, the adhesive member may be formed on both the inner and outer surfaces of the bent portion of the current collector tab.

[0013] In some embodiments, the adhesive member may be adhered between the bent portion of the current collector tab and the outer surface of the electrode assembly.

[0014] In some embodiments, the adhesive member may include an ultraviolet (UV) adhesive.

[0015] In some embodiments, the adhesive member may include an acrylate-based UV adhesive.

[0016] In some embodiments, a method of manufacturing a secondary battery according to the present disclosure may include: providing an electrode assembly including a current collector tab having a bent portion formed by bending the current collector tab at least once, the current collector tab having an end portion coupled to the bent portion and protruding from the electrode assembly; electrically connecting an electrode lead of the secondary battery to the end portion of the current collector tab; forming an adhesive member into the region formed by the bent portion; and curing the adhesive member.

[0017] In some embodiments, forming the adhesive member may include injecting the adhesive member onto the inner surface of the bent portion through an injection nozzle.

[0018] In some embodiments, forming the adhesive member may include dipping the current collector tab having the bent portion into a container provided with the adhesive member such that the adhesive member may be formed to correspond to the bent portion.

[0019] In some embodiments, the method of manufacturing the secondary battery may further include pressing the bent portion into which the adhesive member is formed using a pusher, wherein the pressing brings the bent portion into close contact with the electrode assembly.

[0020] In some embodiments, the adhesive member may include a UV adhesive, and the method may further include curing the adhesive member by irradiating light with a lamp.

[0021] In some embodiments, the pressing end of the pusher may be formed to be convex or concave.

[0022] In some embodiments, the adhesive member may include an acrylate-based UV adhesive.

[0023] In some embodiments, the adhesive member may fix the shape of the bent portion.

[0024] In some embodiments, the method may further include forming a bent portion by bending a current collector tab of the electrode assembly.

[0025] In some embodiments, forming the adhesive member may include forming the adhesive member on both an inner surface and an outer surface of the bent portion of the current collector tab. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a perspective view showing a secondary battery according to an embodiment of the present disclosure.

[0027] Figures 2A through 2J is a view showing a process of manufacturing a secondary battery according to an embodiment of the present disclosure.

[0028] Figures 3A through 3D is a view showing a process of manufacturing a secondary battery according to another embodiment of the present disclosure.

[0029] Figure 4A and Figure 4B is a photograph comparing the shape of a secondary battery according to an embodiment of the present disclosure with a conventional structure. DETAILED DESCRIPTION

[0030] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before that, terms and words used in this specification and claims should not be construed as limited to their ordinary or dictionary meanings, and should be interpreted as meanings and concepts consistent with the technical spirit proposed by the present disclosure based on the principle that the inventor can appropriately define terms to best describe his / her invention. Therefore, since the embodiments disclosed in this specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present disclosure and do not represent all the technical spirit of the present disclosure, it should be understood that there are various equivalents and modifications that can replace them at the time of filing this application. In addition, when used in this specification, "comprising or including" and / or "comprising... or including..." specify the existence of the mentioned shape, quantity, step, operation, member, and / or a group thereof, and do not exclude the existence or addition of one or more other shapes, quantities, steps, operations, members, and / or a group thereof. In addition, when describing embodiments of the present disclosure, "can do" and / or "can be" may include "one or more embodiments of the present disclosure".

[0031] In addition, to assist in understanding the present invention, the drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. In addition, in different embodiments, the same reference numerals may be given to the same components.

[0032] Stating that two objects for comparison are "the same" means that the two objects are "substantially the same". Thus, "substantially the same" may include deviations considered to be at a low level in the art, such as deviations within 5%. In addition, the uniformity of parameters in a certain area may represent uniformity from an average perspective.

[0033] Although first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another, and the first component may also be the second component, unless otherwise stated.

[0034] Throughout the specification, unless otherwise stated, each component may be singular or plural.

[0035] Setting any component "above (or below)" a component or "on (or under)" the component means that the any component may be set in contact with the upper surface (or lower surface) of the component, or another component may be interposed between the component and the any component set on (or under) the component.

[0036] In addition, when describing that a certain component is "connected", "coupled" or "linked" to another component, it should be understood that the components may be directly connected or linked to each other, but another component may be "interposed" between the components, or the components may be "connected", "coupled" or "linked" through yet another component. In addition, the case where a certain part is electrically connected to another part includes not only the case where these parts are directly connected, but also the case where these parts are connected through another element therebetween.

[0037] Throughout the specification, "A and / or B" means A, B, or A and B, unless otherwise stated. That is, "and / or" includes all or any combination of the listed items. "C to D" means greater than or equal to C and less than or equal to D, unless otherwise stated.

[0038] Figure 1 is a perspective view showing a secondary battery according to an embodiment of the present disclosure.

[0039] Refer to Figure 1 , a secondary battery 100 according to an embodiment of the present disclosure includes an electrode assembly 110, a housing 120, and electrode leads 130.

[0040] The electrode assembly 110 may include a first electrode plate, a second electrode plate, and a separator. Here, the first electrode plate may operate as a negative electrode, and the second electrode plate may operate as a positive electrode.

[0041] The first electrode plate is formed by applying a first electrode active material (such as graphite or carbon) to a first electrode current collector formed of a metal foil (such as a copper foil or a nickel foil) and includes a first electrode uncoated portion, which is an area where the first active material is not applied. The first electrode uncoated portion provides a path for current between the first electrode plate and the outside of the first electrode plate.

[0042] The second electrode plate is formed by applying a second electrode active material (such as a transition metal oxide, etc.) to a second electrode current collector formed of a metal foil (such as an aluminum foil) and includes a second electrode uncoated portion, which is an area where the second active material is not applied.

[0043] In addition, the first electrode uncoated portion may form a first current collector tab 111. A plurality of first current collector tabs 111 are provided and formed to protrude from the first electrode plate. The first current collector tabs 111 may be formed to protrude from the first electrode plate in a certain direction and overlap on one side.

[0044] In addition, the second electrode uncoated portion may form a second current collector tab 112. A plurality of second current collector tabs 112 are provided and formed to protrude from the second electrode plate. The second current collector tabs 112 may be formed to protrude from the second electrode plate in a certain direction and overlap on one side. The second current collector tabs 112 and the first current collector tabs 111 may protrude in the same direction and may be positioned to be spaced apart from each other.

[0045] Furthermore, the first current collector tab 111 and the second current collector tab 112 may respectively include bent portions 111a and 112a, and as will be described herein, an adhesive member 113 is formed in the bent portions 111a and 112a. Thus, the bent forms of the first current collector tab 111 and the second current collector tab 112 can be maintained, and the utilization rate of the internal space of the housing 120 and the energy density can be improved.

[0046] In addition, the first current collector tab 111 and the second current collector tab 112 may respectively include ends 111b and 112b where a plurality of protruding uncoated portions gather. These ends 111b and 112b may be welded respectively by a method such as ultrasonic welding, so that the uncoated portions forming the first current collector tab 111 are joined together without coming apart and the uncoated portions forming the second current collector tab 112 are joined together without coming apart. In addition, electrode leads 130 may be respectively coupled to the ends 111b and 112b and protrude to the outside of the housing 120.

[0047] A separator is located between the first electrode plate and the second electrode plate to prevent short - circuits and allow lithium ions to move. For example, the separator can be composed of polyethylene, polypropylene, or a composite film of polyethylene and polypropylene. In some examples, the separator can have an area larger than that of the first electrode plate and the second electrode plate to effectively prevent an electrical short - circuit between the first electrode plate and the second electrode plate.

[0048] In addition, the electrode assembly 110 can be substantially accommodated in the housing 120 together with an electrolyte. The electrolyte can be composed of an organic solvent (such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), or dimethyl carbonate (DMC)) and a lithium salt (such as LiPF6 or LiBF4). In addition, the electrolyte can be in liquid, solid, or gel form. In addition, each of the first current collector tab 111 and the second current collector tab 112 can be electrically connected to the electrode lead 130.

[0049] This electrode assembly 110 can be configured as a so - called stacked type or laminated type because the first electrode plate, the separator, the second electrode plate, and the separator, etc. can be stacked in sequence multiple times. In other words, in some embodiments, the electrode assembly 110 can include a plurality of first electrode plates and a plurality of second electrode plates that are stacked together and separated by separators.

[0050] The housing 120 can generally be composed of a main body 121 and a cover 122, and the main body 121 and the cover 122 are formed as a rectangular bag - shaped film formed integrally and folded in the longitudinal direction on one side. In some embodiments, the housing 120 can not be an integral - type housing and can be a separate bag - shaped film, where the folded portion of the main body 121 and the cover 122 are separated. In some examples, the housing 120 can include or be referred to as a bag - type housing or an outer material. In some examples, the housing 120 can be a multi - layer film composed of a metal layer and insulating layers formed on both sides of the metal layer.

[0051] The main body 121 can include a receiving portion 123, which is a groove for receiving the electrode assembly 110. In addition, the main body 121 can include a sealing portion 124 that extends outward along the edge of the receiving portion 123. The housing 120 can be sealed by placing the electrode assembly 110 in the receiving portion 123 and then heat - fusing the edge of the sealing portion 124 and the cover 122 in a tightly - contacting state. The sealing portion 124 is the portion where the main body 121 and the cover 122 are fused to each other and can extend flatly for a certain length.

[0052] The electrode leads 130 can be electrically connected to the first current collector tab 111 and the second current collector tab 112 respectively. In some examples, the electrode lead 130 connected to the first current collector tab 111 can be a negative electrode lead, and the electrode lead 130 connected to the second current collector tab 112 can be a positive electrode lead. In some examples, the electrode leads 130 can include or be referred to as lead tabs, electrode terminals, or strip terminals.

[0053] The electrode leads 130 can be electrically connected to the ends 111b of the first current collector tab 111 and the ends 112b of the second current collector tab 112 respectively, and extend out of the housing 120 (e.g., protrude from the housing 120). In some examples, the electrode leads 130 can be electrically connected to the first current collector tab 111 and the second current collector tab 112 by welding respectively. In some examples, the electrode leads 130 can extend out through the gap between the sealing portion 124 of the main body 121 and the cover 122. For example, one end of the electrode lead 130 can be connected to the first current collector tab 111 or the second current collector tab 112, and the other end of the electrode lead 130 can extend out of the housing 120 (e.g., protrude from the housing 120). In some examples, the other end of the electrode lead 130 extending to the outside can be referred to as the lead-out portion.

[0054] In addition, the electrode leads 130 can further include an insulating member 135 surrounding the electrode leads 130. The insulating member 135 can be used to prevent electrical short circuits between the electrode leads 130 and the housing 120. In some examples, the insulating member 135 can prevent electrical short circuits between the metal layer of the housing 120 and the electrode leads 130. The insulating member 135 can be located between the sealing portion 124 of the main body 121 and the cover 122. In some examples, when the sealing portion 124 and the cover 122 are heat-fused, the insulating member 135 can be heat-fused together with the sealing portion 124 and the cover 122.

[0055] In some examples, the first current collector tab 111 and the second current collector tab 112 connected to the electrode leads 130 can be bent and accommodated in the accommodating portion 123.

[0056] Figures 2A through 2J is a view showing a process of manufacturing a secondary battery according to an embodiment of the present disclosure.

[0057] In the present disclosure, since the bonding relationship between each of the first current collector tab 111 and the second current collector tab 112 and the electrode leads 130 is the same, the following description will focus on the bonding relationship between the first current collector tab 111 and the electrode leads 130. Therefore, the description of the first current collector tab 111 can equally apply to the second current collector tab 112.

[0058] First, referring to Figure 2A , the first current collector tab 111 can be welded to the electrode lead 130 at the end 111b. Here, the end 111b of the first current collector tab 111 and the electrode lead 130 can overlap to form a welding area W, and welding can be performed in the welding area W by a method such as laser welding. In addition, an insulating member 135 can be formed in the area where the electrode lead 130 will contact the sealing portion 124 of the housing 120.

[0059] Thereafter, referring to Figure 2B and Figure 2C , the first current collector tab 111 can be bent at the bent portion 111a to have a concave shape, and an adhesive member 113 can be formed in the bent portion 111a. Specifically, as Figure 2C shown, the bent portion 111a can form a downwardly concave curved surface such that the first current collector tab 111 at the uppermost end is located on the innermost side, and the adhesive member 113 is applied to the inner side of the curved surface. This adhesive member 113 can maintain the bent shape of the bent portion 111a of the first current collector tab 111 and hold the first current collector tab 111 in a bent state. In addition, the adhesive member 113 can be composed of an ultraviolet (UV) adhesive (such as an acrylate-based UV adhesive), and then the adhesive strength can be increased by UV irradiation, so the shape can be maintained.

[0060] The process of manufacturing this adhesive member 113 is shown successively in Figure 2D and Figure 2F .

[0061] Referring to Figure 2D , in the state where the first current collector tab 111 is bent, the guide member 10 having the groove 11 can be raised as shown by the arrow and can be coupled to the electrode assembly 110. In addition, as Figure 2E shown, the first current collector tab 111 is in a state of being located in the groove 11 of the guide member 10, and the first current collector tab 111 can be temporarily held in a bent state. In addition, the area bent in the first direction in which the first current collector tab 111 protrudes from the electrode assembly 110 is divided by the substantially "U" - shaped bent shape of the first current collector tab 111, and the area bent in the second direction perpendicular to the first direction can also be divided by the guide member 10. Therefore, the bent shape of the first current collector tab 111 is not deformed, and a bent portion 111a having a concave space can be formed in the bent portion.

[0062] Subsequently, referring to Figure 2F, the bonding member 113 can be injected into the bent interior of the first current collector tab 111 through the injection nozzle 20. In this case, the UV adhesive to be injected can be an acrylate-based UV adhesive, and the viscosity can be 20,000 to 30,000 cPs (based on 25 °C). The bonding member 113 can be formed up to the lower end of the welding zone W where the first current collector tab 111 is welded, so that the problem of the base material tab warping in the welding zone W of the first current collector tab 111 can be prevented. As a result of this injection of the bonding member 113, a process of performing the same operation as shown in Figure 2C can be carried out.

[0063] Subsequently, referring to Figure 2G , the pusher 30 can move forward and press the bent portion 111a of the first current collector tab 111, deforming the shape of the bent portion 111a to be flatter. In this case, the pusher 30 to be used can be configured to have a flat end, but in some embodiments, as shown in Figure 2H , the end 31a of the pusher 31 can be formed to be convex, or the end 32a of the pusher 32 can be formed to be concave. In this case, when the end 31a of the pusher 31 is formed to be convex, the bent portion 111a of the first current collector tab 111 can be formed to be concave. In addition, when the end 32a of the pusher 32 is formed to be concave, the bent portion 111a of the first current collector tab 111 can be formed to be convex. Since a relatively small part of the bent portion 111a is pressed due to the shape of the bent portion 111a formed convexly or concavely, a space where the bonding member 113 can accumulate can be further provided. Therefore, the bonding member 113 can be located in the bent portion 111a without flowing to the outside of the first current collector tab 111.

[0064] In addition, referring to Figure 2I , the bonding member 113 can be cured by irradiating light from the lamp 40 onto the bent portion 111a of the first current collector tab 111. Therefore, in a state where the bent inner surfaces of the bent portion 111a face each other, the bent inner surfaces of the bent portion 111a can be fixed by the bonding member 113. In addition, when the curing of the bonding member 113 is completed, as shown in Figure 2J , the electrode assembly 110 can be provided in a form in which the bent portion 111a of the first current collector tab 111 is bent and fixed.

[0065] Therefore, the final electrode assembly 110 can improve the space utilization rate of the upper part of the position where the bent portion 111a of the first current collector tab 111 is located and prevent the first current collector tab 111 from sagging or warping after bending.

[0066] Hereinafter, a process of manufacturing a secondary battery according to another embodiment of the present disclosure will be described.

[0067] Figures 3A through 3D is a view showing a process of manufacturing a secondary battery according to another embodiment of the present disclosure.

[0068] Referring to Figure 3A , in the process of manufacturing a secondary battery according to another embodiment of the present disclosure, the electrode assembly 110 may be immersed in a container in which the bonding member 113 is accommodated, and the electrode assembly 110 is in a state where the bent portion 111a of the first current collector tab 111 is temporarily bent and joined to the guide 10. That is, the bonding member 113 may not be injected through an injection nozzle, and through the process of immersing the bent portion 111a in the bonding member 113, the bonding member 113 may be located not only around the bent portion 111a but also in the space of the bent portion 111a.

[0069] Subsequently, referring to Figure 3B , the bent portion 111a of the first current collector tab 111 may be pressed by the pusher 30, and the bent portion 111a may be compressed. In this case, the bonding member 113 may be located in the inner space of the bent portion 111a and be pressed, and the bonding member 113 may be configured to surround the outside of the bent portion 111a.

[0070] In addition, referring to Figure 3C , thereafter, the bonding member 113 may be cured by the lamp 40. The cured bonding member 113 may also fix the bent portion 111a of the first current collector tab 111 in a bent state.

[0071] Therefore, as Figure 3D shown, the final electrode assembly 110 manufactured by the manufacturing method according to another embodiment of the present disclosure may also increase the space utilization rate of the upper portion of the position where the bent portion 111a of the first current collector tab 111 is located, and prevent the first current collector tab 111 from sagging or warping after bending.

[0072] Hereinafter, an improved effect of a secondary battery according to an embodiment of the present disclosure will be additionally described.

[0073] Figure 4A And Figure 4B are photos for comparing the shape of a secondary battery according to an embodiment of the present disclosure with a conventional structure.

[0074] First, referring to Figure 4A , in the case of an electrode assembly in which a bonding member is not formed in the bent portion, it can be seen that the first current collector tab opens to 107.25° or 111.58°. That is, asFigure 4A As shown, shape deformation may occur in the portion where bending is possible, and thus the problem of drooping of the first current collector tab may occur. Also, it can be seen that since the bent shape of the first current collector tab is open, the utilization rate of the upper part of the electrode assembly is reduced.

[0075] On the other hand, referring to Figure 4B , in the case of a secondary battery according to an embodiment of the present disclosure, it can be seen that the first current collector tab is open to 81.61° or 85.06°. Thus, when comparing the structure in Figure 4B with Figure 4A , it can be seen that the first current collector tab remains in a bent state. Finally, as described above, the structure of the secondary battery according to an embodiment of the present disclosure can prevent the first current collector tab 111 from drooping or warping and increase the utilization rate of the upper part of the electrode assembly 110.

[0076] The secondary battery according to an embodiment of the present disclosure can improve the space utilization rate of the electrode assembly for the upper part where the bent portion of the current collector tab is located, and prevent the current collector tab from drooping or warping after bending by fixing the gap of the bent portion using an adhesive member in the state where the current collector tab is bent.

[0077] What has been described above is only for implementing one embodiment of the secondary battery according to the present disclosure. The present disclosure is not limited to the above-described embodiment, and as claimed in the following claims, without departing from the gist of the present disclosure, the technical spirit of the present disclosure will be considered to the extent that various modifications can be made by those skilled in the art.

[0078] This application claims the priority and the benefit of Korean Patent Application No. 10-2024-0012237, filed with the Korean Intellectual Property Office on January 26, 2024, the entire content of which is incorporated herein by reference.

Claims

1. A secondary battery, comprising: An electrode assembly including a current collector tab, the current collector tab having a bent portion formed by bending the current collector tab at least once, the current collector tab having an end portion coupled to the bent portion and protruding from the electrode assembly; A case, including: A main body formed with a receiving portion configured to receive the electrode assembly; and A cover configured to cover the main body; An electrode lead electrically connected to the end portion of the current collector tab and led out from the case; and An adhesive member formed in a region formed by the bent portion of the current collector tab.

2. The secondary battery according to claim 1, wherein the adhesive member is formed on an inner surface of the bent portion.

3. The secondary battery according to claim 1, wherein the adhesive member fixes the shape of the bent portion.

4. The secondary battery according to claim 1, wherein the region formed by the bent portion is a recessed region, and the adhesive member is received in the recessed region formed when the bent portion is bent.

5. The secondary battery according to claim 1, wherein the adhesive member terminates before the end portion, and the current collector tab is coupled to the electrode lead at the end portion.

6. The secondary battery according to claim 5, wherein the adhesive member is formed to fill an interior of the bent portion and is formed under the end portion of the current collector tab.

7. The secondary battery according to claim 1, wherein the adhesive member is formed on both an inner surface and an outer surface of the bent portion of the current collector tab.

8. The secondary battery according to claim 7, wherein the adhesive member further adheres between the bent portion of the current collector tab and an outer surface of the electrode assembly.

9. The secondary battery according to claim 1, wherein the adhesive member includes an ultraviolet (UV) adhesive.

10. The secondary battery according to claim 9, wherein the adhesive member includes an acrylate-based UV adhesive.

11. A method of manufacturing a secondary battery, the method comprising: Providing an electrode assembly including a current collector tab, the current collector tab having a bent portion formed by bending the current collector tab at least once, the current collector tab having an end portion coupled to the bent portion and protruding from the electrode assembly; Electrically connecting an electrode lead of the secondary battery to the end portion of the current collector tab; Forming an adhesive member into a region formed by the bent portion; And Curing the adhesive member.

12. The method according to claim 11, wherein forming the adhesive member includes injecting the adhesive member onto an inner surface of the bent portion through an injection nozzle.

13. The method according to claim 11, wherein forming the adhesive member includes dipping the current collector tab having the bent portion into a container provided with the adhesive member such that the adhesive member is formed to correspond to the bent portion.

14. The method according to claim 11, further comprising pressing the bent portion into which the adhesive member is formed by using a pusher, wherein the pressing brings the bent portion into close contact with the electrode assembly.

15. The method according to claim 11, wherein: the adhesive member includes an ultraviolet (UV) adhesive; and the method further comprises curing the adhesive member by irradiating light through a lamp.

16. The method according to claim 14, wherein the pressing end portion of the pusher is formed to be convex or concave.

17. The method according to claim 15, wherein the adhesive member includes an acrylate-based UV adhesive.

18. The method according to claim 11, wherein the adhesive member fixes the shape of the bent portion.

19. The method according to claim 11, further comprising forming the bent portion by bending the current collector tab of the electrode assembly.

20. The method according to claim 11, wherein forming the adhesive member includes forming the adhesive member on both the inner surface and the outer surface of the bent portion of the current collector tab.

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