Secondary battery, manufacturing method thereof, and battery pack

Abstract

The present invention relates to a secondary battery which has reduced limitation on shape and improved battery capacity, can reduce the amount of moisture introduced from the outside, and has improved structural stability. According to the present invention, the secondary battery comprises: an electrode assembly; an external film surrounding a part of the electrode assembly; and a cap surrounding the rest of the electrode assembly. The cap comprises: a connection part coupled to the external film; a terminal part partially buried in the connection part; and an outer surface part covering at least a part of the outer surface of the terminal part, which faces the outside of the electrode assembly.

Description

Secondary battery and manufacturing method thereof, battery pack

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0104209, filed August 5, 2024, Korean Patent Application No. 10-2024-0071802, filed May 31, 2024, and Korean Patent Application No. 10-2023-0117851, filed September 5, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a secondary battery, and more specifically, to a secondary battery capable of being charged and discharged, a method for manufacturing the same, and a battery pack.

[0005] In recent years, rising energy prices due to the depletion of fossil fuels and growing concerns about environmental pollution have made the demand for eco-friendly alternative energy sources essential for future living. Research is continuing into various power generation technologies, such as solar, wind, and tidal power. Furthermore, significant interest is being focused on power storage devices, such as batteries, to more efficiently utilize the generated electricity.

[0006] Moreover, with the technological development and increasing demand for battery-powered electronic mobile devices and electric vehicles, the demand for batteries as an energy source is rapidly increasing, and accordingly, much research is being conducted on batteries that can meet various needs.

[0007] Batteries that store electrical energy can generally be divided into primary and secondary batteries. Primary batteries are disposable, consumable batteries, whereas secondary batteries are rechargeable batteries manufactured using materials capable of repeatable oxidation and reduction processes between current and a substance. In other words, when current causes a reduction reaction in a material, the battery is charged, and when an oxidation reaction occurs in the material, the battery is discharged. This repeated charge-discharge cycle generates electricity.

[0008] Secondary batteries can be classified into cylindrical cells, pouch cells, and prismatic cells based on their shape. Among them, pouch cells can be manufactured in a form in which an electrode assembly in which a positive electrode, a negative electrode, and a separator are laminated is accommodated inside a pouch, and the outer part of the pouch is sealed.

[0009] Secondary batteries can be classified into cylindrical cells, pouch cells, and prismatic cells based on their shape. Among them, pouch cells can be manufactured in a form in which an electrode assembly in which a positive electrode, a negative electrode, and a separator are laminated is accommodated inside a pouch, and the outer part of the pouch is sealed.

[0010] Conventional pouch cells suffer from cracks in the pouch film during the forming process, resulting in significant waste after the degassing process. Furthermore, the material properties of the pouch film limit the depth at which it can be formed, limiting any increase in battery capacity.

[0011] Therefore, there is a need for a secondary battery that has relatively few restrictions on shape while allowing for increased battery capacity.

[0012] The object of the present invention is to provide a secondary battery having improved battery capacity, reduced amount of moisture flowing in from the outside, and improved structural stability while having fewer restrictions on shape.

[0013] A secondary battery according to the present invention includes an electrode assembly, an outer film covering a portion of the electrode assembly, and a cap covering the remainder of the electrode assembly, wherein the cap may include a connecting portion coupled to the outer film, a terminal portion partially embedded in the connecting portion, and an outer surface portion covering at least a portion of a surface facing the outside of the electrode assembly among the outer surfaces of the terminal portion.

[0014] The terminal portion may include a first member exposed to the outside of the connection portion, and a second member extending from the first member toward the electrode assembly.

[0015] The above outer surface portion can cover the outer surface of the first member.

[0016] The second member may be provided so that one end of the electrode assembly side is exposed to the inside of the connecting portion.

[0017] The second member may be formed in a plurality of pieces, and at least one of the second members may be provided such that one end of the electrode assembly side is exposed to the inside of the connecting portion.

[0018] The secondary battery may further include a bus bar that is disposed between the terminal portion and the electrode assembly and connects one end of the second member exposed to the inside of the connection portion and the electrode assembly.

[0019] The second member may further include a third member extending from the side of the first member toward the electrode assembly and embedded in the connecting portion so as to be covered by the connecting portion, and the terminal portion may further include a third member extending from the first member toward the electrode assembly and penetrating the connecting portion so as to be exposed to the inside of the connecting portion.

[0020] The secondary battery may further include a bus bar that is disposed between the terminal portion and the electrode assembly and connects the third member exposed inside the connecting portion and the electrode assembly to each other.

[0021] The bus bar may include a first metal portion that contacts the third member, and a second metal portion that extends from the first metal portion toward the electrode assembly and has one end connected to the electrode assembly.

[0022] A hole may be formed in the outer surface portion so that the outer surface of the terminal portion can be exposed to the outside.

[0023] The above terminal portion may include a terminal member penetrating the outer surface portion.

[0024] The end portion of the above terminal member may protrude outward from the outer surface portion.

[0025] The terminal portion may be arranged so that one side protrudes away from one side of the connecting portion in a direction away from the electrode assembly.

[0026] The terminal portion may be at least partially embedded in the connecting portion.

[0027] The terminal portion may include a first member exposed to the outside of the connection portion; and a second member extending from the first member toward the electrode assembly and embedded in the connection portion.

[0028] A method for manufacturing a secondary battery according to an embodiment of the present invention comprises the steps of providing an electrode assembly including a positive electrode and a negative electrode, surrounding a portion of the electrode assembly with an outer film, and covering a remaining portion of the electrode assembly with a cap, wherein the cap includes a connecting portion coupled to the outer film, a terminal portion partially embedded in the connecting portion, and an outer surface portion covering at least a portion of a surface facing the outside of the electrode assembly among outer surfaces of the terminal portion, wherein at least a portion of the terminal portion can be embedded in the connecting portion.

[0029] A battery pack according to an embodiment of the present invention may include a plurality of the aforementioned secondary batteries, and a packaging that accommodates the plurality of secondary batteries.

[0030] Since the secondary battery according to a preferred embodiment of the present invention does not have a process for forming an outer film, there are fewer restrictions on the shape in which the outer film accommodates the electrode assembly, the possibility of defects such as cracks occurring in the outer film is reduced, and the battery capacity can be improved.

[0031] In addition, the safety of the secondary battery can be improved by reducing the degree to which moisture, etc., penetrates from the outside of the secondary battery into the inside of the secondary battery.

[0032] Additionally, the terminal portion can be electrically connected to the electrode assembly in various forms by a bus bar.

[0033] In addition, the structural stability of the secondary battery can be improved by the bonding relationship and arrangement form of the terminal and connection parts.

[0034] Additionally, the terminal portion can be protected from external impact or contamination by the outer surface.

[0035] In addition, the terminal portion and the connecting portion are joined to each other, so that the bonding between the terminal portion and the connecting portion can be improved.

[0036] In addition, since the terminal portion is covered by the outer surface portion, insulation between the terminal portion and other components can be improved, and heat transfer in a thermal runaway situation can be suppressed.

[0037] In addition, since the terminal portion is surrounded by the outer surface portion and the connecting portion, the cap can be easily manufactured by an insert injection process. In addition, since at least a portion of the terminal portion is placed in a state of being embedded in the connecting portion, the structural stability of the cap can be improved.

[0038] The effects according to the present invention are not limited to the contents exemplified above, and more diverse effects are included in this specification.

[0039] FIG. 1 is a perspective view schematically illustrating a secondary battery according to Example 1 of the present invention.

[0040] Figure 2 is an exploded perspective view schematically illustrating a secondary battery according to Example 1 of the present invention.

[0041] FIG. 3 is a cross-sectional view schematically illustrating a cross-section of a cap of a secondary battery according to Example 1 of the present invention taken along line A-A' of FIG. 2.

[0042] Fig. 4 is a cross-sectional view schematically illustrating a modified example of the cap according to Fig. 3.

[0043] FIG. 5 is a cross-sectional view schematically illustrating a cap and a bus bar of a secondary battery according to Example 2 of the present invention.

[0044] Fig. 6 is a cross-sectional view schematically illustrating a modified example of the cap according to Fig. 5.

[0045] Fig. 7 is a cross-sectional view schematically illustrating another modified example of the cap according to Fig. 3.

[0046] Fig. 8 is a cross-sectional view schematically illustrating another modified example of the cap according to Fig. 3.

[0047] Figure 9 is an exploded perspective view schematically illustrating a battery pack according to Example 5 of the present invention.

[0048] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0049] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0050] In addition, terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0051] Example 1

[0052] FIG. 1 is a perspective view schematically illustrating a secondary battery (10) according to Embodiment 1 of the present invention, and FIG. 2 is an exploded perspective view schematically illustrating a secondary battery (10) according to Embodiment 1 of the present invention.

[0053] A secondary battery (10) according to Example 1 of the present invention may include an electrode assembly (100), an outer film (200), and a cap (300). Below, each component of the secondary battery (10) will be described in more detail. For reference, the contents of Example 1 may be equally applied to the following examples, as long as they do not conflict with each other.

[0054] The electrode assembly (100) of the secondary battery (10) may include a positive electrode, a negative electrode, and a separator. Here, the separator may be placed between the positive electrode and the negative electrode to physically separate the positive electrode and the negative electrode. The electrode assembly (100) may be in the form of a stacked positive electrode, a negative electrode, and a separator, or in the form of a jelly-roll in which the positive electrode, the negative electrode, and the separator are rolled up.

[0055] Meanwhile, the electrode assembly (100) may be provided with an electrode tab (110) connected to the electrode. The electrode tab (110) may be provided separately or as part of a current collector constituting the electrode. For reference, if the electrode assembly (100) is an all-solid-state battery, a solid electrolyte may be provided instead of a separator.

[0056] Referring to FIG. 2, the secondary battery (10) according to Embodiment 1 of the present invention may include an outer film (200). The outer film (200) of the secondary battery (10) may be provided to wrap a portion of the electrode assembly (100). Specifically, the outer film (200) may be provided to wrap a cap (300) to be described later and the electrode assembly (100). More specifically, the outer film (200) may be combined with the cap (300) to form an internal space, and the electrode assembly (100) may be accommodated in the internal space.

[0057] In order to wrap the electrode assembly (100), the outer film (200) may be made of a material that can be shaped. For example, the outer film (200) may be bendable.

[0058] Additionally, the outer film (200) may be formed of a non-elastic material. Conventionally, a pouch film was formed to form a space to accommodate the electrode assembly. However, since the outer film (200) does not require a shape change through molding, it may be formed of a non-elastic material. That is, the outer film (200) may not be elastic.

[0059] The outer film (200) of the secondary battery (10) may have a shape in which a sheet or film is rolled along the side of the electrode assembly (100). That is, the outer film (200) may be arranged in a shape that wraps around the side of the electrode assembly (100). At this time, one end and the other end of the outer film (200) may be arranged in a shape that wraps around the electrode assembly (100) while meeting each other. With respect to the shape in which one end and the other end of the outer film (200) meet each other, a case in which one side of one end and the other side of the other end are joined so as to be in contact with each other (see FIG. 2) is possible, and a case in which one side of one end and one side of the other end are joined so as to be in contact with each other is also possible. This is merely an example, and the shape in which one end and the other end of the outer film (200) are joined to form a space that accommodates the electrode assembly (100) may vary.

[0060] With regard to the method by which one end and the other end of the outer film (200) are joined, one end and the other end of the outer film (200) may be joined to each other by heat sealing or heat and pressure sealing. That is, the outer film (200) may include a material having heat sealing properties. Specifically, the outer film (200) may include a material that melts by heat and has adhesive properties.

[0061] For example, the outer film (200) may include a sealant layer, a barrier layer, and an insulating layer.

[0062] The sealant layer may include one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber. Mainly, a polyolefin resin such as polypropylene (PP) or polyethylene (PE) may be used. In particular, polypropylene (PP) may have excellent mechanical properties such as tensile strength, rigidity, surface hardness, wear resistance, and heat resistance, and chemical properties such as corrosion resistance. The barrier layer may include one or more materials selected from the group consisting of iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), aluminum (Al), stainless steel (STS), and an alloy.

[0063] The insulating layer may include one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber.

[0064] Meanwhile, the outer film (200) may be arranged to wrap a portion of the electrode assembly (100), and the cap (300) may be arranged to wrap the remainder of the electrode assembly (100). Specifically, when the outer film (200) is arranged to wrap the electrode assembly (100) along the side of the electrode assembly (100), outer openings may be formed at both ends of the electrode assembly (100). The cap (300) of the secondary battery (10) is combined with the outer film (200) in a form that covers the outer openings at both ends of the electrode assembly (100), and the electrode assembly (100) may be accommodated in the internal space formed by the outer film (200) and the cap (300).

[0065] As an example of a method of joining the cap (300) and the outer film (200), the cap (300) and the outer film (200) may be joined by welding. Specifically, the connecting portion (310) may include a metal material, and the outer film (200) may include a metal layer that can be joined to the connecting portion (310) by welding at a portion facing the connecting portion (310).

[0066] As another example of a method of joining the cap (300) and the outer film (200), the cap (300) and the outer film (200) may be joined by sealing. Specifically, the connecting portion (310) may include a resin material having adhesiveness by heat, and the outer film (200) may include a resin layer that can be joined to the connecting portion (310) by heat and pressure at a portion facing the connecting portion (310). Here, the resin layer may include a material having sealing properties by heat as described above.

[0067] Conventional pouch cells were formed by forming a cup portion to accommodate an electrode assembly (100) by forming a sheet or film. During the forming process of the cup portion, the depth that can be formed was limited depending on the material properties of the sheet or film, and the capacity that could accommodate the electrode assembly (100) was also limited. In addition, when forming a sheet or film, the thickness at the corners was the thinnest, so defects such as cracks frequently occurred. In addition, conventional pouch cells required a gas collection portion to collect gas in the degassing process to remove gas accumulated inside the pouch, and there were many cases where the gas collection portion was removed and discarded after the degassing process.

[0068] On the other hand, in the secondary battery (10) according to Example 1 of the present invention, since the outer film (200) can be used according to the volume of the electrode assembly (100), there may be no limitation on the capacity that can accommodate the electrode assembly (100). In addition, since molding of the cup portion is not required, the occurrence of defects such as cracks in the outer film (200) can be prevented, and the material and thickness of the outer film (200) can be selected relatively freely. In addition, since the electrolyte injection and degassing processes can be performed through the cap (300), the outer film (200) is not discarded, so the economic feasibility of the process can be improved.

[0069] Meanwhile, although not described in detail in the present invention, the cap (300) may further include an electrolyte injection port for injecting an electrolyte or a gas discharge port for discharging gas in a degassing process.

[0070] FIG. 3 is a cross-sectional view schematically illustrating a portion of a cross-section taken along line A-A' of FIG. 2 of a secondary battery (10) according to Example 1 of the present invention, and FIG. 4 is a cross-sectional view schematically illustrating a modified example of a cap (300) according to FIG. 3.

[0071] Referring to FIG. 3, the cap (300) of the secondary battery (10) according to Example 1 of the present invention may include a connection portion (310) and a terminal portion (320).

[0072] The connection portion (310) of the cap (300) may be coupled with the outer film (200). In addition, the terminal portion (320) of the cap (300) may be coupled to the connection portion (310) and may be provided to be exposed to the outside and inside of the connection portion (310), respectively. Here, the inside of the connection portion (310) may refer to a part of the internal space formed by the cap (300) and the outer film (200), and the outside of the connection portion (310) may refer to the outer space of the cap (300) and the outer film (200). Meanwhile, a portion of the terminal portion (320) exposed to the inside of the connection portion (310) may be electrically connected to the electrode assembly (100). At this time, the electrical connection may include both a direct connection between the terminal portion (320) and the electrode assembly (100) and an indirect connection via another electrically conductive member.

[0073] Meanwhile, as an example of a method for joining the connecting portion (310) and the terminal portion (320), joining by sealing is possible. The terminal portion (320) may include a metal material, and the connecting portion (310) may include a resin material that has adhesive properties due to heat. Accordingly, the resin material of the connecting portion (310) that has adhesive properties due to heat melts, and can be joined to the terminal portion (320) by pressure.

[0074] As an example of a configuration for improving the structural stability of the cap (300), at least a portion of the terminal portion (320) of the cap (300) according to Embodiment 1 of the present invention may be embedded in the connecting portion (310). In this regard, the terminal portion (320) of the cap (300) may include a first member (321) and a second member (322).

[0075] The first member (321) of the terminal portion (320) may be provided so that a portion thereof is exposed to the outside of the connection portion (310). Accordingly, the terminal portion (320) electrically connected to the electrode assembly (100) may be in electrical contact with the outside through the first member (321) provided to be exposed to the outside of the connection portion (310). That is, the secondary battery (10) may provide electrical energy to the outside through the first member (321).

[0076] The second member (322) of the terminal portion (320) may extend toward the electrode assembly (100). That is, the second member (322) may extend from the first member (321) toward the electrode assembly (100). Specifically, the second member (322) may be provided so that one end on the electrode assembly (100) side is exposed to the inside of the connection portion (310). Here, the inside of the connection portion (310) may mean a part of the internal space formed by the outer film (200) and the cap (300).

[0077] Referring to FIG. 3, the second member (322) of the terminal portion (320) may be formed in a plurality. In addition, at least one second member (322) may be provided so that one end on the electrode assembly (100) side is exposed to the inside of the connection portion (310). Specifically, among the plurality of second members (322) extending from the first member (321) toward the electrode assembly (100), some may be embedded in the connection portion (310), and some may be exposed to the inside of the connection portion (310). With reference to FIG. 3, the second member (322) illustrated on the left may be embedded in the connection portion (310), and the second member (322) illustrated on the right may be exposed to the inside of the connection portion (310).

[0078] The second member (322) extending to the inside of the connecting portion (310) may have one end on the electrode assembly (100) side electrically connected to the electrode assembly (100). Here, the electrical connection may include both a direct connection between the second member (322) and the electrode assembly (100) and an indirect connection via another electrically conductive member.

[0079] When the second member (322) and the electrode assembly (100) are directly connected, the electrode tab (110) of the electrode assembly (100) may be connected to the second member (322). In addition, when the second member (322) and the electrode assembly (100) are indirectly connected, the secondary battery (10) may include a bus bar (400) as an example of an electrically conductive member that serves as an intermediary.

[0080] The bus bar (400) is arranged between the terminal portion (320) and the electrode assembly (100) to connect one end of the second member (322) exposed to the inside of the connection portion (310) and the electrode assembly (100). The bus bar (400) may be made of metal so as to have electrical conductivity. In addition, the bus bar (400) may be arranged in various shapes depending on the extended length of the second member (322), etc. FIG. 3 is a drawing illustrating a case where the bus bar (400) according to Embodiment 1 of the present invention has a roughly plate or bar shape.

[0081] Meanwhile, according to a modified example of Embodiment 1 of the present invention, all second members (322) may be provided so that one end of the electrode assembly (100) side is exposed to the inside of the connection portion (310). Specifically, a plurality of second members (322) extending from the first member (321) toward the electrode assembly (100) may all be exposed to the inside of the connection portion (310).

[0082] As described above, when the second member (322) and the electrode assembly (100) are directly connected, the electrode tab (110) of the electrode assembly (100) may be connected to the second member (322). In addition, when the second member (322) and the electrode assembly (100) are indirectly connected, the secondary battery (10) may include a plurality of bus bars (400) as an example of an electrically conductive member that serves as an intermediary.

[0083] Referring to FIG. 4, a plurality of bus bars (400) of a secondary battery (10) according to a modified example may be connected to a second member (322) at the inner side of a connecting portion (310), respectively. In this case, the electrode assembly (100) may be electrically connected to the second member (322) at a plurality of locations. Accordingly, when the secondary battery (10) includes a plurality of electrode assemblies (100), the plurality of electrode assemblies (100) may be electrically connected to bus bars (400) arranged at respective nearby locations. Through this, the secondary battery (10) may efficiently increase battery capacity.

[0084] Meanwhile, the cap (300) according to the first embodiment of the present invention may be arranged so that one side of the terminal portion (320) protrudes away from one side of the connection portion (310) in a direction away from the electrode assembly (100). Specifically, one side of the first member (321) may be arranged so as to protrude further outward from one side of the connection portion (310) than one side of the connection portion (310). With reference to FIG. 3 or 4, one side of the first member (321) and one side of the connection portion (310) may refer to the respective upper surfaces. In this case, it may be easy for an object from which electrical energy is to be obtained to contact the protruding first member (321).

[0085] As another example related to the arrangement of the first member (321), one side of the first member (321) may be arranged on the same plane as one side of the connecting portion (310). In this case, since there is no portion of the first member (321) that protrudes outward from the connecting portion (310), arrangement may be easy when arranging multiple secondary batteries (10).

[0086] The cap (300) of the secondary battery (10) according to the first embodiment of the present invention can cover the electrode assembly (100) with the connection portion (310) and the terminal portion (320) at least partially embedded in the connection portion (310). Depending on the material of the connection portion (310), moisture or the like on the outside of the connection portion (310) can penetrate into the connection portion (310) through the connection portion (310). The penetration of moisture can cause a defect in the secondary battery (10). The cap (300) of the secondary battery (10) according to the first embodiment of the present invention can reduce the area of ​​the connection portion (310) through which moisture can penetrate by covering the electrode assembly (100) together with the connection portion (310) and the terminal portion (320) made of metal. In addition, since at least a portion of the terminal portion (320) is arranged in a shape in which it is embedded in the connection portion (310), the moisture penetration path formed between the terminal portion (320) and the connection portion (310) can be formed in a shape in which moisture is difficult to penetrate. Accordingly, the secondary battery (10) according to the first embodiment of the present invention can reduce the phenomenon in which problems occur in the performance of the secondary battery (10) by reducing the amount of moisture penetrating into the interior.

[0087] In addition, the cap (300) of the secondary battery (10) according to Example 1 of the present invention can be placed in a state where the second member (322) of the terminal portion (320) is embedded in the connecting portion (310). Accordingly, the connecting portion (310) restricts movement of the terminal portion (320) and prevents detachment of the terminal portion (320), thereby improving the structural stability of the secondary battery (10).

[0088] Although not described in detail in Embodiment 1 of the present invention, the cap (300) may further include a gas discharge member (not shown) for discharging gas inside the secondary battery (10) or a venting member (not shown) for inducing venting in a specific direction.

[0089] Example 2

[0090] FIG. 5 is a cross-sectional view schematically illustrating a cap (300') and a bus bar (400') of a secondary battery (10) according to Example 2 of the present invention, and FIG. 6 is a cross-sectional view schematically illustrating a modified example of the cap (300') according to FIG. 5.

[0091] Hereinafter, a detailed description of the same configuration as that of the secondary battery (10) according to Embodiment 1 of the present invention will be omitted, and differences will be specifically described. The secondary battery (10) according to Embodiment 2 of the present invention may differ from the secondary battery (10) according to Embodiment 1 in the shape of the terminal portion (320'), the shape of the bus bar (400'), the method of combining the configuration, etc.

[0092] A secondary battery (10) according to Embodiment 2 of the present invention may include an electrode assembly (100), an outer film (200), and a cap (300'). The outer film (200) of the secondary battery (10) may be provided to wrap a portion of the electrode assembly (100). Specifically, the outer film (200) may be provided to wrap the cap (300) and the electrode assembly (100). More specifically, the outer film (200) may be combined with the cap (300) to form an internal space, and the electrode assembly (100) may be accommodated in the internal space.

[0093] The cap (300') of the secondary battery (10) may include a connection portion (310) and a terminal portion (320'). The connection portion (310) of the cap (300') may be coupled with the outer film (200), and the terminal portion (320') of the cap (300) may be coupled to the connection portion (310) and be exposed to the outside and inside of the connection portion (310), respectively. Here, the inside of the connection portion (310) may mean a part of the internal space formed by the cap (300') and the outer film (200), and the outside of the connection portion (310) may mean the outer space of the cap (300') and the outer film (200). Meanwhile, a portion of the terminal portion (320') exposed to the inside of the connection portion (310) may be electrically connected to the electrode assembly (100).

[0094] As an example of a configuration for efficient electrical connection with the electrode assembly (100), the terminal portion (320') of the cap (300') according to Embodiment 2 of the present invention may further include a third member (323).

[0095] Referring to FIG. 5, the third member (323) of the terminal portion (320') may extend from the first member (321) toward the electrode assembly (100). Specifically, the third member (323) may be provided to penetrate the connection portion (310) so as to be exposed to the inside of the connection portion (310). Preferably, the third member (323) may have a shape extending from the center of the surface of the first member (321) facing the electrode assembly (100) toward the electrode assembly (100). Depending on the shape of the third member (323), the bus bar (400') to be described later may be arranged in various shapes, and the contact area between the third member (323) and the bus bar (400') may be increased, thereby improving structural stability.

[0096] Meanwhile, since the third member (323) is electrically connected to the electrode assembly (100), the second member (322) can be disposed in a form in which it is entirely embedded in the connecting portion (310). Here, the second member (322) can extend from the side of the first member (321) toward the electrode assembly (100). Preferably, the second member (322) can be formed along the edge of the first member (321). Since the second member (322) formed along the edge of the first member (321) is disposed in a state in which it is entirely embedded in the connecting portion (310), the structural stability of the cap (300') can be improved. In this case, a path that is relatively difficult for moisture to penetrate is formed between the connecting portion (310) and the terminal portion (320), so that moisture penetration toward the interior of the secondary battery (10) can be effectively prevented. This is just one example, and the second member (322) may be formed only at one pair of opposing corners among the four corners of the first member (321) having a roughly rectangular cross-section.

[0097] As an example of a configuration for electrically connecting the third member (323) and the electrode assembly (100), the secondary battery (10) according to Embodiment 2 of the present invention may further include a bus bar (400'). Specifically, the bus bar (400') may be arranged between the terminal portion (320') and the electrode assembly (100) to connect the third member (323) exposed to the inside of the connection portion (310) and the electrode assembly to each other.

[0098] As an example of a configuration for efficient connection with the third member (323), a bus bar (400') according to Embodiment 2 of the present invention may include a first metal part (410), a second metal part (420), a third metal part (430), and a fourth metal part (440).

[0099] Referring to FIG. 5, the first metal portion (410) may be in contact with the third member (323). For example, the first metal portion (410) may have a substantially plate shape and may extend in parallel with the extension direction of the first member (321). In addition, the first metal portion (410) may be arranged so that a surface facing the third member (323) is in contact with the third member (323). At this time, the third member (323) includes a metal material, and the third member (323) and the first metal portion (410) may be joined to each other through welding.

[0100] The second metal portion (420) may extend from the first metal portion (410) toward the electrode assembly (100). At this time, the second metal portion (420) may extend in a direction approximately orthogonal to the extension direction of the first metal portion (410).

[0101] The third metal portion (430) may extend from the second metal portion (420) toward the outer film (200). At this time, the third metal portion (430) may extend in a direction approximately orthogonal to the extension direction of the second metal portion (420). Specifically, the third metal portion (430) may extend in a direction away from the third member (323).

[0102] The fourth metal portion (440) may extend from the third metal portion (430) toward the electrode assembly (100). In addition, one end of the fourth metal portion (440) may be connected to the electrode assembly (100). Specifically, one end of the fourth metal portion (440) may be connected to the electrode tab (110) of the electrode assembly (100).

[0103] The bus bar (400') including the first metal portion (410), the second metal portion (420), the third metal portion (430), and the fourth metal portion (440) can be changed into various shapes depending on the number, arrangement, shape, etc. of the electrode assembly (100).

[0104] Referring to Fig. 6, a bus bar (400') according to a modified example of Embodiment 2 of the present invention may be composed of a first metal portion (410) and a second metal portion (420). Here, one end of the second metal portion (420) may be connected to the electrode assembly (100). In this case, the bus bar (400') may be placed in a space formed on the inside of the connection portion (310) by the connection portion (310). Therefore, when the electrode assembly (100) is placed, space efficiency may be improved, and battery capacity may be increased.

[0105] Meanwhile, an adhesive (500) may be used as a configuration for bonding between the connecting portion (310) and the terminal portion (320'). That is, the connecting portion (310) and the terminal portion (320') may be bonded to each other by the adhesive (500) applied between the connecting portion (310) and the terminal portion (320'). In addition, the connecting portion (310) and the outer film (200) may also be bonded to each other by the adhesive (500) applied between the connecting portion (310) and the outer film (200). Here, the type and application form of the adhesive (500) for bonding may vary. Preferably, the adhesive (500) may be composed of a material having relatively high hydrophobicity.

[0106] Example 3

[0107] Fig. 7 is a cross-sectional view schematically illustrating a cap (300) and a bus bar (400) of a secondary battery according to Embodiment 3 of the present invention. The connection portion (310), terminal portion (320), and bus bar (400) of the cap (300) according to this embodiment may be configured identically to the connection portion, terminal portion, and bus bar of the embodiment illustrated in Fig. 3, respectively.

[0108] Referring to FIG. 7, in the present embodiment, the cap (300) may further include an outer surface portion (330). The outer surface portion (330) is configured to cover the outer surface of the terminal portion (320) facing the outside of the electrode assembly (hereinafter, referred to as the outward surface). As a result, the outward surface of the terminal portion (320) can be protected from external impact or contamination.

[0109] At this time, the outer surface (330) may be connected to the connecting portion (310). In other words, the outer surface (330) may be provided as an integral part with the connecting portion (310). The outer surface (330) may be made of the same material as the connecting portion (310). This may improve the bonding between the terminal portion (320) and the connecting portion (310).

[0110] Meanwhile, in the present embodiment, the outer surface (330) may cover at least a portion of the outward-facing surface. Here, covering at least a portion of the surface may include covering a region of the surface and covering the entire surface.

[0111] In this embodiment, the outward surface may be provided on the terminal portion (321). Referring to FIG. 7, the outward surface may be a surface facing upward among the outer surfaces of the first member (321). In this embodiment, the outer surface portion (330) may entirely cover the upper surface of the first member (321).

[0112] Meanwhile, the electrode assembly can be electrically connected to the outside via the terminal portion (320). For this purpose, a predetermined hole (331) may be formed in the outer surface portion (330). In the present embodiment, the outwardly facing surface of the first member (321) may be exposed to the outside through the hole (331). In this case, the portion exposed to the outside may be a portion of the outwardly facing surface. Through this, the external terminal may be inserted into the hole (331) and thus be electrically connected to the terminal portion (320).

[0113] In this way, in this embodiment, since the outward surface is covered by the outer surface (330), not only is durability and bondability improved, but insulation between the terminal portion and other components can be improved, and heat transfer can be suppressed in a thermal runaway situation.

[0114] Furthermore, in the present embodiment, since the terminal portion (320) made of a metal material is surrounded by the outer portion (330) and the connection portion (310), the cap (300) can be easily manufactured using an insert injection process. This improves the productivity of the secondary battery, simplifies the manufacturing process, and reduces manufacturing costs.

[0115] Example 4

[0116] Fig. 8 is a cross-sectional view schematically illustrating a cap (300) and a bus bar (400) of a secondary battery according to Embodiment 4 of the present invention. The connection portion (310), terminal portion (320), outer surface portion (330), first member (321), second member (322) of the terminal portion (320) and bus bar (400) of the cap (300) according to the present embodiment may be configured identically to the connection portion, terminal portion, outer surface portion, first member, second member and bus bar of the terminal portion of Embodiment 3 illustrated in Fig. 7, respectively.

[0117] Referring to Fig. 8, the terminal portion (320) may further include a terminal member (324). In the present embodiment, the terminal member (324) may extend from the first member (321). The terminal member (324) may penetrate the outer surface portion (330) and be exposed to the outside of the secondary battery.

[0118] In this embodiment, the terminal member (324) can penetrate the hole (331) of the outer surface portion (330). The end of the terminal member (324) can protrude outward from the outer surface portion (330). Through this, the external terminal can be electrically connected to the terminal member (324).

[0119] Example 5

[0120] Fig. 9 is an exploded perspective view schematically illustrating a battery pack (1) according to Embodiment 5 of the present invention. The battery pack (1) according to Embodiment 5 of the present invention may include a plurality of secondary batteries (10). In addition, the battery pack (1) may include a packaging (20) that accommodates a plurality of secondary batteries (10) therein. In this case, the secondary batteries (10) may be secondary batteries according to any one of the first to fourth embodiments described above.

[0121] The packaging (20) may take various forms. For example, the packaging (20) may include a bus bar electrically connected to a plurality of secondary batteries (10). Here, the packaging (20) may further include a bus bar frame for securing the bus bar. The number of secondary batteries (10) accommodated within the packaging (20) may vary depending on the battery pack (1).

[0122] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0123] [Explanation of symbols]

[0124] 1: Battery pack

[0125] 10: Secondary battery

[0126] 20: Packaging

[0127] 100: Electrode assembly

[0128] 200: Exterior film

[0129] 300, 300': Cap

[0130] 310: Connector

[0131] 320, 320': Terminal

[0132] 321: First Absence

[0133] 322: Second Absence

[0134] 323: Third Absence

[0135] 324: Absence of terminal

[0136] 330: Exterior

[0137] 400, 400': Bus bar

[0138] 410: First Metal Department

[0139] 420: Second Metal Department

[0140] 430: Third Metal Division

[0141] 440: 4th Metal Division

[0142] 500: Adhesive

Claims

1. Electrode assembly; An outer film covering a portion of the electrode assembly; and including a cap covering the remainder of the electrode assembly; The above cap is, A connecting portion that is combined with the above outer film; A terminal portion, some of which is embedded in the above connecting portion; and A secondary battery comprising an outer surface portion covering at least a portion of the outer surface of the terminal portion facing the outside of the electrode assembly.

2. In claim 1, The above terminal part, A first member exposed to the outside of the above connecting portion; and A secondary battery comprising a second member extending from the first member toward the electrode assembly.

3. In claim 2, A secondary battery, wherein the outer surface covers the outer surface of the first member.

4. In claim 2, The second member above is, A secondary battery, wherein one end of the electrode assembly is exposed to the inside of the connecting portion.

5. In claim 4, A secondary battery further comprising a bus bar disposed between the terminal portion and the electrode assembly, the bus bar connecting one end of the second member exposed to the inside of the connection portion and the electrode assembly to each other.

6. In claim 2, The second member above is, extending from the side of the first member toward the electrode assembly and embedded in the connecting portion so as to be covered by the connecting portion; The above terminal part, A secondary battery further comprising a third member extending from the first member toward the electrode assembly and penetrating the connecting portion so as to be exposed to the inside of the connecting portion.

7. In claim 6, A secondary battery further comprising a bus bar disposed between the terminal portion and the electrode assembly, the bus bar connecting the third member exposed to the inside of the connection portion and the electrode assembly to each other.

8. In claim 7, The above bus bar, A first metal part in contact with the third member; and A secondary battery comprising a second metal portion extending from the first metal portion toward the electrode assembly and having one end connected to the electrode assembly.

9. In claim 1, A secondary battery having a hole formed in the outer surface so that the outer surface of the terminal portion can be exposed to the outside.

10. In claim 1, The above terminal part, A secondary battery comprising a terminal member penetrating the outer surface.

11. In claim 10, A secondary battery, wherein the end of the terminal member protrudes outward from the outer surface.

12. In claim 1, The above terminal part, A secondary battery, wherein one side is arranged to protrude away from the electrode assembly from one side of the connecting portion.

13. In claim 1, The above terminal part, A secondary battery, at least a portion of which is embedded in the above connecting portion.

14. In claim 13, The above terminal part, A first member exposed to the outside of the above connecting portion; and A secondary battery comprising a second member extending from the first member toward the electrode assembly and embedded in the connecting portion.

15. A step of providing an electrode assembly including an anode and a cathode; A step of surrounding a portion of the above electrode assembly with an outer film; and comprising the step of covering the remainder of the electrode assembly with a cap; The above cap is, A connecting portion bonded to the above outer film; A terminal portion, some of which is embedded in the above connecting portion; and A method for manufacturing a secondary battery, comprising an outer surface portion covering at least a portion of a surface facing the outside of the electrode assembly among the outer surfaces of the terminal portion.

16. Secondary battery according to multiple claims 1; and A battery pack comprising a packaging that accommodates the plurality of secondary batteries.

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