Secondary battery

Abstract

The present invention relates to a secondary battery which can be repeatedly charged / discharged. A secondary battery according to an embodiment of the present invention comprises: an electrode assembly; an exterior material accommodating the electrode assembly; and a coupling member coupled to the outer surface of the exterior material. The exterior material includes a first pouch and a second pouch coupled to each other to form an accommodation space for accommodating the electrode assembly. The coupling member is coupled to an edge of a coupling part to which the first pouch and the second pouch are coupled. A notched region in which the first pouch and the second pouch are notched is formed in at least one of corners of the coupling part. A coupling line coupled to the coupling part is formed in the coupling member. The coupling line may have a curved shape at a corner part of the coupling member.

Description

secondary battery

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0193985 dated December 23, 2024 and Korean Patent Application No. 10-2025-0190724 dated December 4, 2025, 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 capable of repeated charging and discharging.

[0005] A secondary battery is a battery capable of repeated charging and discharging, and may have a structure in which an electrode assembly and an electrolyte are housed inside an outer casing. Among secondary batteries, a pouch cell is formed by joining a pair of pouches that form a housing space for the electrode assembly and the electrolyte, and a thermal fusion method may be used for joining these pouches.

[0006] Specifically, a pair of pouches is a laminate sheet having a multilayer structure, and the inner layer of the laminate sheet may be composed of a resin material. The inner layers of each of the pair of pouches are heated and pressurized while facing each other to thermally fuse, thereby sealing the receiving space that accommodates the electrode assembly and the electrolyte.

[0007] At this time, as the charging and discharging of the secondary battery are repeated, residual moisture in the electrolyte inside the secondary battery or moisture penetrating from the outside reacts with the lithium salt to generate HF (hydrogen fluoride), and gases such as carbon dioxide, carbon monoxide, ethylene, and methane may be generated due to the decomposition of the electrolyte. In addition, depending on the material of the positive electrode included in the electrode assembly, additional hydrogen and HF may be generated, which can lead to overheating due to overcharging and internal short circuits during the charging and discharging process. Consequently, a large amount of gas may be generated inside the secondary battery.

[0008] As such, when a large amount of gas is generated inside the secondary battery, the connection between a pair of thermally fused pouches that seal the internal space is released, and there is a problem where the internal electrolyte leaks through the released connection.

[0009] The present invention was devised in recognition of the above problems, and the objective of the present invention is to provide a secondary battery with improved bonding strength of the sealing portion in which pouches are fused together.

[0010] A secondary battery according to a first embodiment of the present invention comprises: an electrode assembly; an outer casing for housing the electrode assembly; and a coupling member coupled to the outer surface of the outer casing. The outer casing comprises a first pouch and a second pouch that are coupled to each other to form a housing space for housing the electrode assembly. The coupling member is coupled to the edge of a coupling portion where the first pouch and the second pouch are coupled. At least one of the corners of the coupling portion has a notched area formed in which the first pouch and the second pouch are notched. A coupling line coupled to the coupling portion is formed on the coupling member, and the coupling line may have a curved shape at the corner portion of the coupling member.

[0011] At least one of the first pouch and the second pouch has a concave cup portion formed to form the receiving space drawn, and the connecting portion may be formed along the edge of the cup portion.

[0012] The above-mentioned coupling member includes a first coupling member coupled to one side of the coupling portion; and a second coupling member coupled to the other side of the coupling portion, wherein a coupling line coupled to the coupling portion may be formed on each of the first coupling member and the second coupling member.

[0013] The first coupling member may include a portion coupled to one surface of the coupling portion; and a portion connected to the second coupling member.

[0014] The second coupling member may include a portion coupled to the other side of the coupling portion; and a portion connected to the first coupling member.

[0015] The first connecting member and the second connecting member may be connected to each other in the portion of the connecting part where the notching area is formed.

[0016] The first connecting member and the second connecting member may be composed of the same material.

[0017] A secondary battery according to a first embodiment of the present invention comprises: an electrode assembly; an outer casing for housing the electrode assembly; and a coupling member coupled to the outer surface of the outer casing. The outer casing comprises a first pouch and a second pouch that are coupled to each other to form a housing space for housing the electrode assembly. The coupling member is coupled to the edge of a coupling portion where the first pouch and the second pouch are coupled, and at least one of the corners of the coupling portion has a notched area formed in which the first pouch and the second pouch are notched. A coupling line coupled to the coupling portion is formed on the coupling member. The coupling line may include a first coupling line formed along the centerline of the coupling member; and a second coupling line formed at the corner portion of the coupling member and partially overlapping with the first coupling line.

[0018] Meanwhile, a secondary battery according to a second embodiment of the present invention comprises: an electrode assembly; an outer casing for housing the electrode assembly; a coupling member coupled to the outer surface of the outer casing; and an additional member provided at the edge of the outer casing, wherein the outer casing comprises a first pouch and a second pouch that are coupled to each other to form a housing space for housing the electrode assembly, and the coupling member is coupled to the edge of a coupling portion in which the first pouch and the second pouch are coupled, and a notching area in which the first pouch and the second pouch are notched is formed at least one of the corners of the coupling portion, and the coupling member comprises a first coupling member coupled to one side of the coupling portion; and a second coupling member coupled to the other side of the coupling portion, and the additional member may occupy at least a portion of the part in which the notching area is formed among the corners of the coupling portion.

[0019] The thickness of the above additional member may be less than or equal to the thickness of the above joint.

[0020] The first coupling member may include a portion coupled to one surface of the coupling portion; and a portion coupled to one surface of the additional member.

[0021] The second coupling member may include a portion coupled to the other side of the coupling portion; and a portion coupled to the other side of the additional member.

[0022] The first connecting member, the second connecting member, and the additional member may be composed of the same material.

[0023] In a secondary battery according to a second embodiment of the present invention, a coupling line coupled to the additional member and the coupling portion may be formed in the coupling member.

[0024] The above-mentioned joint line may have a curved shape at the corner portion of the joint member.

[0025] The above-mentioned coupling line may include a first coupling line formed along the centerline of the coupling member; and a second coupling line formed at the corner of the coupling member and partially overlapping with the first coupling line.

[0026] According to a secondary battery according to one embodiment of the present invention, a coupling member is additionally coupled to the edge of the coupling portion where the first pouch and the second pouch are coupled, thereby providing an advantageous effect of delaying or preventing the coupling of the first pouch and the second pouch from being released when the internal pressure of the secondary battery increases.

[0027] FIG. 1 is a cross-sectional view showing the schematic structure of a secondary battery according to a first embodiment of the present invention.

[0028] Figure 2 is a drawing showing the cup portions formed in the first pouch and the second pouch.

[0029] FIG. 3 is a drawing showing a notched corner of a joint where the first pouch and the second pouch are joined.

[0030] Figure 4 is an enlarged view of part A of Figure 3.

[0031] FIG. 5 is a drawing for explaining that a coupling member is coupled to the coupling portion of the first pouch and the second pouch.

[0032] FIG. 6 is a drawing for explaining the connection structure of the first and second connecting members.

[0033] FIG. 7 is a diagram illustrating the process of a coupling member of a secondary battery according to a first embodiment of the present invention being coupled to a coupling portion.

[0034] FIG. 8 is a cross-sectional view showing the schematic structure of a secondary battery according to a second embodiment of the present invention.

[0035] FIG. 9 is a drawing for explaining that an additional member covers the notched portion of the joint between the first pouch and the second pouch.

[0036] FIG. 10 is a drawing for explaining the process of a coupling member of a secondary battery according to a second embodiment of the present invention being coupled to a coupling part.

[0037] Hereinafter, preferred embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0038] 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.

[0039] Furthermore, terms and 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.

[0040] First embodiment

[0041] FIG. 1 is a cross-sectional view illustrating the schematic structure of a secondary battery according to a first embodiment of the present invention. FIG. 2 is a drawing illustrating the appearance of a cup portion formed in a first pouch and a second pouch.

[0042] Referring to FIGS. 1 and 2, a secondary battery (10) according to the present invention may include an electrode assembly (100), an outer casing (200) that accommodates the electrode assembly (100), and a coupling member (300) that is coupled to the edge of the outer casing (200). At this time, the outer casing (200) includes a first pouch (210) and a second pouch (220) that are coupled to each other to form a receiving space (S) that accommodates the electrode assembly (100), and the coupling member (300) may be coupled to both sides of a coupling portion (230) where the first pouch (210) and the second pouch (220) are coupled to improve the sealing degree of the receiving space (S).

[0043] In this case, both sides of the coupling portion (230) where the first pouch (210) and the second pouch (220) are coupled are pressed by the coupling member (300), so there is an advantageous effect of delaying or preventing the coupling of the first pouch (210) and the second pouch (220) from being released when the internal pressure of the secondary battery (10) increases.

[0044] The electrode assembly (100) includes a plurality of electrodes and a separator and can be configured in various ways. For example, the electrode assembly (100) may be a laminate in which a plurality of electrodes and a separator are alternately stacked. Additionally, the electrode assembly (100) may have a jelly-roll shape formed by stacking the electrodes and separators and then winding them in one direction.

[0045] The outer casing (200) is a case of a secondary battery (10) that forms a receiving space (S) for receiving an electrode assembly (100) and an electrolyte, and can be configured in various ways. In particular, the outer casing (200) may be a pouch-type case in which the edges (212, 222) of a first pouch (210) and a second pouch (220) are fused.

[0046] The first pouch (210) and the second pouch (220) are made of a laminate sheet material, and a concave cup portion (211, 221) forming a receiving space (S) can be drawn on either the first pouch (210) or the second pouch (220). At this time, some of the terrace portions (212, 222), which are the edges of each of the cup portions (211, 221), can be joined together to form a joining portion (230). That is, the joining portion (230) can be formed along the edge of the receiving space (S) formed by the first pouch (210) and the second pouch (220).

[0047] Meanwhile, the laminate sheet constituting the first and second pouches (210, 220) may be a multilayer sheet including a metal layer such as aluminum or stainless steel. In this case, a resin layer is essentially formed on the inner surface of the metal layer, and a resin layer may be optionally formed on the outer surface of the metal layer.

[0048] The metal layer can serve as a substrate that maintains mechanical strength and as a barrier layer that prevents the penetration of moisture and oxygen. In addition to preventing the ingress or leakage of foreign substances such as gas and moisture, the metal layer may be composed of aluminum or an aluminum alloy to improve the strength of the battery case. Aluminum alloys such as alloy numbers 8079, 1N30, 8021, 3003, 3004, 3005, 3104, and 3105 may be used, and these may be used individually or in combination of two or more.

[0049] The resin layer that can be coated on the outer surface of the metal layer must possess excellent resistance to the external environment to protect the electrode assembly from the outside; therefore, the resin layer requires excellent tensile strength and corrosion resistance relative to its thickness. For such a resin layer, polyester-based resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), and polyolefin-based resins such as polyethylene and polypropylene may be used.

[0050] The resin layer coated on the inner surface of the metal layer is a layer that seals the internal space in which the electrode assembly is accommodated by bonding to the resin layers of different pouches, and may be composed of a polyolefin-based resin. For example, the second resin layer may use CPP (Casted Polypropylene), chlorinated polypropylene, polyethylene, ethylene-propylene copolymer, polyethylene-acrylic acid copolymer, and polypropylene-acrylic acid copolymer.

[0051] The coupling member (300) is a member coupled to both sides of the coupling portion (230) in which the terrace portions (212, 222) of the first pouch (210) and the second pouch (220) are coupled, and the coupling member (300) may be composed of a pair of members (310, 320). Specifically, the coupling member (300) may be composed of a first coupling member (310) coupled to one side of the coupling portion (230) and a second coupling member (320) coupled to the other side of the coupling portion (230).

[0052] At this time, the first and second connecting members (310, 320) may form a connected integral member made of the same material. That is, the connecting member (300) is a single member, and the first and second connecting members (310, 320) may be separate parts of the connecting member (300) for convenience.

[0053] For example, the connecting member (300) may be a metal structure formed by folding a metal sheet twice. The inner surfaces of both sides of this metal structure become the inner surface of the first connecting member (310) and the inner surface of the second connecting member (320), respectively, and the inner surfaces of the first connecting member (310) and the second connecting member (320) may be connected to both sides of the connecting portion (230). At this time, a certain free volume may be formed between the connecting portion (230) and the connecting member (300), which is a metal structure. However, this free volume is not always formed, and if the connecting member (300) is in close contact with the connecting portion (230), the free volume may not be formed.

[0054] Meanwhile, FIG. 3 is a drawing showing a notched corner of a joint where the first pouch and the second pouch are combined, and FIG. 4 is an enlarged view of part A of FIG. 3.

[0055] Referring to FIGS. 3 and 4, at least one of the corners of the combined portion (230) where the terrace portions (212, 222) of the first pouch (210) and the second pouch (220) are joined may have a notched area (231) formed where the first pouch (210) and the second pouch (220) are notched together.

[0056] The notching area (231) is an empty space formed by cutting the joining portion (230) where the terrace portions (212, 222) of the first pouch (210) and the second pouch (220) are joined, and may be formed at the corner of the joining portion (230) where the terrace portions (212, 222) of the first pouch (210) and the second pouch (220) are joined. The notching area (231) may have various shapes. For example, as shown in FIGS. 3 and 4, the notching area (231) may be an empty space formed by cutting the joining portion (230) into a triangular shape.

[0057] FIG. 5 is a drawing for explaining that a coupling member is coupled to the coupling portion of the first pouch and the second pouch. FIG. 6 is a drawing for explaining the connection structure of the first and second coupling members.

[0058] Referring to FIGS. 5 and 6, the first coupling member (310) may include a portion (311) coupled to one side of the coupling portion (230) and a portion (312) coupled to the second coupling member (320). Additionally, the second coupling member (320) may include a portion (321) coupled to the other side of the coupling portion (230) and a portion (322) coupled to the first coupling member (310).

[0059] The first connecting member (310) covers the entire edge of the terrace portion (212) of the first pouch (210), and the second connecting member (320) can cover the entire edge of the terrace portion (222) of the second pouch (220). That is, the first connecting member (310) and the second connecting member (320) each cover both sides of the connecting portion (230), and the first connecting member (310) and the second connecting member (320) can also cover the portion of the connecting portion (230) where the notching area (231) is formed. At this time, the first connecting member (310) and the second connecting member (320) can be connected to each other in the portion of the connecting portion (230) where the notching area (231) is formed.

[0060] Additionally, the first connecting member (310) and the second connecting member (320) may be composed of various materials. In particular, the first connecting member (310) and the second connecting member (320) may be composed of the same material.

[0061] For example, the first connecting member (310) and the second connecting member (320) may both be made of a metal material. Accordingly, the portion (312) of the first connecting member (310) facing the second connecting member (320) and the portion (322) of the second connecting member (320) facing the first connecting member (310) may be joined to each other by welding.

[0062] At this time, the portion of the first connecting member (310) that is in contact with the terrace portion (212) of the first pouch (210) can be connected to the terrace portion (212). When the first pouch (210) has a two-layer structure of a metal layer and a resin layer formed on the inner surface of the metal layer, the outer surface of the terrace portion (212) of the first pouch (210) is made of a metal material, so that when heat is applied to the first connecting member (310), the first connecting member can be connected to the terrace portion (212) of the first pouch (210).

[0063] Likewise, when the second pouch (220) has a two-layer structure of a metal layer and a resin layer formed on the inner surface of the metal layer, the portion of the second coupling member (320) that is in contact with the terrace portion (222) of the second pouch (220) can be coupled to the terrace portion (222). Since the outer surface of the terrace portion (222) of the second pouch (220) is made of a metal material, when heat is applied to the second coupling member (320), the second coupling member can be coupled to the terrace portion (222) of the second pouch (220).

[0064] Meanwhile, the first connecting member (310) and the second connecting member (320) may both be composed of a resin material. Accordingly, the portion (312) of the first connecting member (310) facing the second connecting member (320) and the portion (322) of the second connecting member (320) facing the first connecting member (310) may be joined to each other by thermal fusion.

[0065] At this time, when the first pouch (210) has a three-layer structure in which a metal layer and a resin layer are formed on each side of the metal layer, the outer surface of the terrace portion (212) of the first pouch (210) is made of a resin material, and the portion of the first bonding member (310) that is in contact with the terrace portion (212) of the first pouch (210) can be fused to the terrace portion (212).

[0066] Likewise, when the first pouch (220) has a three-layer structure in which a metal layer and a resin layer are formed on each side of the metal layer, the outer surface of the terrace portion (222) of the second pouch (220) is also made of a resin material, so that the part of the second bonding member (320) that is in contact with the terrace portion (222) of the second pouch (220) can be fused to the terrace portion (222).

[0067] FIG. 7 is a diagram illustrating the process of a coupling member of a secondary battery according to a first embodiment of the present invention being coupled to a coupling portion. FIG. 7 illustrates different methods of coupling the coupling member.

[0068] < of Fig. 7<Case 1> In the drawing, a first coupling member (310) is shown being coupled to one side of the coupling portion (230) along a coupling line. Although not shown in the drawing, a second coupling member (320) may also be coupled to the other side of the coupling portion (230) along the same coupling line. A coupling unit that couples the first and second coupling members (310, 320) to the coupling portion (230) may heat or pressurize the first and second coupling members (310, 320) and the coupling portion (230) along the coupling line.

[0069] That is, < of Fig. 7<Case 1> When the coupling member (300) and the coupling part (230) are heated or pressurized according to the method, a coupling line for coupling with the coupling part (230) can be seen on the outer surface of the coupling member (300). This coupling line may have a square ring shape formed along the centerline of the coupling member (300). Since the coupling member (300) includes first and second coupling members (310, 320), the square ring-shaped coupling line may be formed on the outer surface of each of the first and second coupling members (310, 320).

[0070] < of Fig. 7<Case 2> A method of joining a first joining member (310) placed on one side of a joining part (230) twice is illustrated. At this time, the first joining member (310) may be heated or pressed along joining line 1, and subsequently heated or pressed along joining line 2. A second joining member (320) placed on the other side of the joining part (230) may also be heated or pressed in the same way. In this way, when both sides of the joining part (230) are heated or pressed multiple times, there is an advantageous effect of improving the joining strength between the first and second joining members (310, 320) and the corner portion of the joining part (230).

[0071] < of Fig. 7<Case 2> According to the method, if the coupling member (300) and the coupling part (230) are heated or pressed twice, first and second coupling lines may be formed in the coupling member (300) and coupled with the coupling part (230). The first coupling line may have a square ring shape formed along the centerline of the coupling member (300). The second coupling line is formed in the corner portion of the coupling member (300) and may have a straight line shape extending diagonally. At this time, the first and second coupling lines may overlap in part. In this way, when the coupling line is composed of the first and second coupling lines, there is an advantageous effect of improving the coupling strength of the corner portions of the coupling member (300) and the coupling part (230). Meanwhile, the coupling member (300) includes the first and second coupling members (310, 320), and the first and second coupling lines may be formed in each of the first and second coupling members (310, 320).

[0072] < of Fig. 7<Case 3> In the drawing, a first connecting member (310) is shown being connected to one side of the connecting portion (230) along a connecting line. This connecting line may be partially curved at the corner portion of the connecting portion (230). Although not shown in the drawing, a second connecting member (320) may also be connected to the other side of the connecting portion (230) along the same connecting line.

[0073] < of Fig. 7<Case 3> When the coupling member (300) and the coupling part (230) are heated or pressurized according to the method, a coupling line for coupling with the coupling part (230) can be identified on the outer surface of the coupling member (300). This coupling line is formed along the centerline of the coupling member (300) and may have a polygonal ring shape that is curved at the corner portion. In this way, when the coupling line has a polygonal ring shape that is curved at the corner portion, there is an advantageous effect of improving the coupling strength of the corner portions of the coupling member (300) and the coupling part (230). Additionally, since the coupling member (300) includes first and second coupling members (310, 320), the polygonal ring-shaped coupling line may be formed on the outer surface of each of the first and second coupling members (310, 320).

[0074] Meanwhile, < of Fig. 7<Case 1> > or <<Case 3> The joint line formed in each case may be a weld line welded by a welding device. Specifically, if the first and second pouches (210, 220) have a two-layer structure composed of a metal layer and a resin layer formed on the inner surface of the metal layer, the outermost surface of the joint portion (230) to which the first and second pouches (210, 220) are joined may be composed of a metal layer. In this case, if the first and second joint members (310, 320) are composed of a metal material, the first and second joint members (310, 320) may be welded to the joint portion (230). Accordingly, the joint line formed on the outer surface of each of the first and second joint members (310, 320) may be a weld line welded by a welding device.

[0075] Also, < of Fig. 7<Case 1> > or <<Case 3> The bonding line formed in each case may be a heat-fusion line formed by a heat-fusion unit. Specifically, if the first and second pouches (210, 220) have a three-layer structure composed of a metal layer and a resin layer formed on the inner and outer surfaces of the metal layer, respectively, the outermost surface of the bonding portion (230) to which the first and second pouches (210, 220) are bonded may be composed of a resin layer. At this time, if the first and second bonding members (310, 320) are composed of a resin material, the first and second bonding members (310, 320) may be heat-fused to the bonding portion (230). Accordingly, the bonding line formed on the outer surface of each of the first and second bonding members (310, 320) may be a heat-fusion line formed by a heat-fusion unit.

[0076] 2nd embodiment

[0077] The secondary battery according to the second embodiment of the present invention differs from the first embodiment in that it further includes an additional member provided at the edge of the outer casing. Hereinafter, details common to the first embodiment will be omitted as much as possible, and the second embodiment will be described focusing on the differences. That is, it is obvious that if details not explained in the second embodiment are necessary, they may be considered as belonging to the first embodiment.

[0078] FIG. 8 is a cross-sectional view illustrating the schematic structure of a secondary battery according to a second embodiment of the present invention. FIG. 9 is a drawing for explaining that an additional member covers the notched portion of the joint between the first pouch and the second pouch.

[0079] Referring to FIGS. 8 and 9, a secondary battery (10) according to a second embodiment of the present invention may include an additional member (400) provided at the edge of an outer casing (200). Specifically, the secondary battery (10) may further include an additional member (400) that occupies at least a portion of the corner of the coupling portion (230) of the outer casing (200) where a notching area (231) is formed. That is, the additional member (400) may be a member that occupies at least a portion of the empty space which is the notching area (231). The thickness of the additional member (400) may be the same as the thickness of the coupling portion (230) or thinner than the thickness of the coupling portion (230).

[0080] At this time, the first coupling member (310) may be composed of a part (311) that contacts or is coupled to one side of the coupling part (230) and a part (312) that is coupled to one side of the additional member (400). The second coupling member (320) may be composed of a part (321) that contacts or is coupled to the other side of the coupling part (230) and a part (322) that is coupled to the other side of the additional member (400).

[0081] The first connecting member (310) covers the entire edge of the terrace portion (212) of the first pouch (210), and the second connecting member (320) can cover the entire edge of the terrace portion (222) of the second pouch (220). That is, the first connecting member (310) and the second connecting member (320) each cover both sides of the connecting portion (230), and the first connecting member (310) and the second connecting member (320) can also cover the additional member (400) inserted into the notching area (231) of the connecting portion (230). At this time, the first connecting member (310) and the second connecting member (320) can each be connected to one side and the other side of the additional member (400).

[0082] Meanwhile, the first connecting member (310), the second connecting member (320), and the additional member (400) may be composed of various materials. In this case, the first connecting member (310), the second connecting member (320), and the additional member (400) may all be composed of the same material.

[0083] For example, the first connecting member (310), the second connecting member (320), and the additional member (400) may all be made of metal material. Accordingly, the portion (312) of the first connecting member (310) that is in contact with one side of the additional member (400) may be joined to the additional member (400) by welding. Additionally, the portion (322) of the second connecting member (320) that is in contact with the other side of the additional member (400) may be joined to the additional member (400) by welding.

[0084] Here, when the first pouch (210) has a two-layer structure of a metal layer and a resin layer formed on the inner surface of the metal layer, the portion of the first coupling member (310) that is in contact with the terrace portion (212) of the first pouch (210) can be coupled to the terrace portion (212). Since the outer surface of the terrace portion (212) of the first pouch (210) is made of a metal material, when heat is applied to the first coupling member (310), the first coupling member can be coupled to the terrace portion (212) of the first pouch (210).

[0085] Additionally, when the second pouch (220) has a two-layer structure of a metal layer and a resin layer formed on the inner surface of the metal layer, the portion of the second connecting member (320) that is in contact with the terrace portion (222) of the second pouch (220) can be connected to the terrace portion (222). Since the outer surface of the terrace portion (222) of the second pouch (220) is made of a resin material, when heat is applied to the second connecting member (320), the second connecting member (320) can be connected to the terrace portion (222) of the second pouch (220).

[0086] Meanwhile, the first connecting member (310), the second connecting member (320), and the additional member (400) may all be composed of a resin material. Accordingly, the portion (312) of the first connecting member (310) that is in contact with one side of the additional member (400) may be connected to the additional member (400) by heat fusion. Additionally, the portion (322) of the second connecting member (320) that is in contact with the other side of the additional member (400) may be connected to the additional member (400) by heat fusion.

[0087] At this time, when the first pouch (210) and the second pouch (220) have a three-layer structure in which a metal layer and a resin layer are formed on each side of the metal layer, the outer surface of the terrace portion (212) of the first pouch (210) is made of a resin material, so that the part of the first connecting member (310) in contact with the terrace portion (212) of the first pouch (210) can be fused to the terrace portion (212). Likewise, the outer surface of the terrace portion (222) of the second pouch (220) is also made of a resin material, so that the part of the second connecting member (320) in contact with the terrace portion (222) of the second pouch (220) can be fused to the terrace portion (222).

[0088] FIG. 10 is a diagram illustrating the process of a coupling member of a secondary battery according to a second embodiment of the present invention being coupled to a coupling portion. FIG. 10 illustrates different methods of coupling a coupling member to a coupling portion.

[0089] < of Fig. 10<Case 1> In the drawing, it is shown that a first connecting member (310) is connected to one side of the connecting portion (230) and the additional member (400) along a connecting line. Although not shown in the drawing, a second connecting member (320) may also be connected to the other side of the connecting portion (230) and the additional member (400) along the same connecting line. A connecting unit that presses the first and second connecting members (310, 320) to the connecting portion (230) and the additional member (400) may heat or pressurize the first and second connecting members (310, 320), the connecting portion (230), and the additional member (400) along the connecting line.

[0090] That is, < of Fig. 10<Case 1> When the coupling member (300), additional member (400), and coupling part (230) are heated or pressurized according to the method, a coupling line formed by the additional member (400) and the coupling part (230) may be formed on the outer surface of the coupling member (300). This coupling line may have a square ring shape formed along the centerline of the coupling member (300). Since the coupling member (300) includes first and second coupling members (310, 320), the square ring-shaped coupling line may be formed on the outer surface of each of the first and second coupling members (310, 320).

[0091] < of Fig. 10<Case 2> A method of joining a first joining member (310) placed on one side of a joining part (230) and an additional member (400) twice is illustrated. At this time, the first joining member (310) is heated or pressed first along joining line 1, and may subsequently be heated or pressed again along joining line 2. A second joining member (320) placed on the other side of the joining part (230) and the additional member (400) may also be heated or pressed in the same way. In this way, when both sides of the part where the additional member (400) is provided are heated and pressed multiple times, there is an advantageous effect of improving the bonding strength between the first and second joining members (310, 320) and the additional member (400). In particular, when the first connecting member (310), the second connecting member (320), and the additional member (400) are all made of the same material, there is an advantageous effect in that the bonding strength between the first and second connecting members (310, 320) and the additional member (400) is further enhanced.

[0092] < of Fig. 10<Case 2> According to the method, when the coupling member (300), additional member (400), and coupling part (230) are heated and pressed twice, first and second coupling lines may be formed in the coupling member (300) for coupling with the additional member (400) and the coupling part (230). The first coupling line may have a square ring shape formed along the centerline of the coupling member (300). The second coupling line may have a straight line shape formed at the corner of the coupling member (300) and extended diagonally. At this time, the first and second coupling lines may overlap in part. In this way, when the coupling line is composed of the first and second coupling lines, there is an advantageous effect of improving the coupling force between the corner of the coupling member (300) and the additional member (400). Meanwhile, the coupling member (300) includes first and second coupling members (310, 320), and the first and second coupling lines may be formed on the outer surface of each of the first and second coupling members (310, 320).

[0093] < of Fig. 10<Case 3> A method is illustrated in which a first coupling member (310), seated on one side of the coupling portion (230) and the additional member (400), is heated or pressed along a coupling line. The coupling line may be partially curved at the portion where the additional member (400) is provided. Although not illustrated in the drawing, a second coupling member (320), seated on the other side of the coupling portion (230) and the additional member (400), may also be heated or pressed along the same coupling line.

[0094] < of Fig. 10<Case 3> According to the method, when the coupling member (300), additional member (400), and coupling portion (230) are heated or pressurized, a coupling line may be formed on the outer surface of the coupling member (300). This coupling line may be formed along the centerline of the coupling member (300) and may have a polygonal ring shape that is curved at the corner portion. In this way, when the coupling line has a polygonal ring shape that is curved at the corner portion, there is an advantageous effect of improving the coupling force between the corner portion of the coupling member (300) and the additional member (400). Additionally, since the coupling member (300) includes first and second coupling members (310, 320), the polygonal ring-shaped coupling line may be formed on the outer surface of each of the first and second coupling members (310, 320).

[0095] Meanwhile, < of Fig. 10<Case 1> > or <<Case 3> The joint line formed in each case may be a weld line welded by a welding device. Specifically, if the first and second pouches (210, 220) have a two-layer structure composed of a metal layer and a resin layer formed on the inner surface of the metal layer, the outermost surface of the joint portion (230) to which the first and second pouches (210, 220) are joined may be composed of a metal layer. In this case, if the first and second joint members (310, 320) and the additional member (400) are all composed of a metal material, the first and second joint members (310, 320) may be welded to the joint portion (230) and the additional member (400). Accordingly, the joint line formed on the outer surface of each of the first and second joint members (310, 320) may be a weld line welded by a welding device.

[0096] Also, < of Fig. 10<Case 1> > or <<Case 3> The bonding line formed in each case may be a heat-fusion line formed by a heat-fusion unit. Specifically, if the first and second pouches (210, 220) have a three-layer structure composed of a metal layer and a resin layer formed on the inner and outer surfaces of the metal layer, respectively, the outermost surface of the bonding portion (230) to which the first and second pouches (210, 220) are bonded may be composed of a resin layer. At this time, if the first and second bonding members (310, 320) and the additional member (400) are all composed of a resin material, the first and second bonding members (310, 320) may be heat-fused to the bonding portion (230) and the additional member (400). Accordingly, the bonding line formed on the outer surface of each of the first and second bonding members (310, 320) may be a heat-fusion line formed by a heat-fusion unit.

[0097] 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.

[0098] [Explanation of the symbol]

[0099] 10: Secondary battery 100: Electrode assembly

[0100] 200: Exterior material 210: 1st pouch

[0101] 220: Second pouch 230: Connecting part

[0102] 300: Connecting member 310: First connecting member

[0103] 320: Second connecting member 400: Additional member

[0104] S: Accommodation space

Claims

1. Electrode assembly; An outer casing that accommodates the above electrode assembly; and It includes a connecting member that is connected to the outer surface of the above exterior material, The above outer material includes a first pouch and a second pouch that are combined with each other to form a receiving space for accommodating the electrode assembly, and The above-mentioned coupling member is coupled to the edge of the coupling portion where the first pouch and the second pouch are coupled, and At least one of the corners of the above-mentioned joint portion has a notched area formed in which the first pouch and the second pouch are notched. A connection line connected to the connection portion is formed in the above-mentioned connecting member, and The above-mentioned coupling line is a secondary battery having a curved shape at the corner portion of the coupling member.

2. In Claim 1, A secondary battery in which at least one of the first pouch and the second pouch has a concave cup portion formed to form the receiving space, and the coupling portion is formed along the edge of the cup portion.

3. In Claim 1, The above-mentioned connecting member is, A first coupling member coupled to one surface of the above-mentioned coupling portion; and It includes a second coupling member coupled to the other side of the above-mentioned coupling portion, A secondary battery in which the coupling line coupled to the coupling portion is formed in each of the first coupling member and the second coupling member.

4. In Claim 3, The first coupling member above is, A portion coupled to one surface of the above-mentioned coupling portion; and A secondary battery including a portion connected to the second coupling member.

5. In Claim 4, The above second connecting member is, A portion coupled to the other side of the above-mentioned coupling portion; and A secondary battery including a portion connected to the first coupling member.

6. In Claim 5, A secondary battery in which the first coupling member and the second coupling member are connected to each other in the portion of the coupling portion where the notching region is formed.

7. In Claim 3, The above first coupling member and second coupling member are composed of the same material and are a secondary battery.

8. Electrode assembly; An outer casing that accommodates the above electrode assembly; and It includes a connecting member that is connected to the outer surface of the above exterior material, The above outer material includes a first pouch and a second pouch that are combined with each other to form a receiving space for accommodating the electrode assembly, and The above-mentioned coupling member is coupled to the edge of the coupling portion where the first pouch and the second pouch are coupled, and At least one of the corners of the above-mentioned joint portion has a notched area formed in which the first pouch and the second pouch are notched. A connection line connected to the connection portion is formed in the above-mentioned connecting member, and The above connection line is, A first connecting line formed along the centerline of the above connecting member; and A secondary battery comprising a second coupling line formed at the corner portion of the above-mentioned coupling member and partially overlapping with the first coupling line.

9. Electrode assembly; An outer casing that accommodates the above electrode assembly; A coupling member coupled to the outer surface of the above exterior material; and It includes an additional member provided at the edge of the above exterior material, The above outer material includes a first pouch and a second pouch that are combined with each other to form a receiving space for accommodating the electrode assembly, and The above-mentioned coupling member is coupled to the edge of the coupling portion where the first pouch and the second pouch are coupled, and At least one of the corners of the above-mentioned joint portion has a notched area formed in which the first pouch and the second pouch are notched. The above-mentioned connecting member is, A first coupling member coupled to one surface of the above-mentioned coupling portion; and It includes a second coupling member coupled to the other side of the above-mentioned coupling portion, The above additional member is a secondary battery that occupies at least a portion of the part where the notching area is formed among the corners of the above-mentioned joint.

10. In Claim 9, A secondary battery in which the thickness of the additional member is less than or equal to the thickness of the joint portion.

11. In Claim 9, The first coupling member above is, A portion coupled to one surface of the above-mentioned coupling portion; and A secondary battery comprising a portion coupled to one side of the above additional member.

12. In Claim 11, The above second connecting member is, A portion coupled to the other side of the above-mentioned coupling portion; and A secondary battery comprising a portion coupled to the other side of the above additional member.

13. In Claim 9, The above first connecting member, second connecting member and additional member are composed of the same material in a secondary battery.

14. In Claim 9, A secondary battery in which a coupling line coupled to the additional member and the coupling part is formed in the coupling member.

15. In Claim 14, The above-mentioned coupling line is a secondary battery having a curved shape at the corner portion of the coupling member.

16. In Claim 14, The above connection line is, A first connecting line formed along the centerline of the above connecting member; and A secondary battery comprising a second coupling line formed at the corner portion of the above-mentioned coupling member and partially overlapping with the first coupling line.

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