Secondary battery

Abstract

A secondary battery according to an embodiment of the present invention may comprise: an electrode assembly; an exterior material formed of a sheet so as to have an internal space for accommodating the electrode assembly and an exterior material opening for communicating the internal space with the outside; and a cap for covering the exterior material opening. The cap may comprise: an exterior portion coupled to the exterior material; and a terminal portion disposed to cover the exterior material opening with the exterior portion, exposed to the outside and the inside of the exterior portion, and electrically connected to the electrode assembly at a portion exposed to the inside of the exterior portion. The terminal portion may include a material having lower moisture permeability than a material included in the exterior portion. The area in which the terminal portion covers the exterior material opening may be 90% or more of the area in which the cap covers the exterior material opening.

Description

secondary battery

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0003706, filed January 9, 2024, and Korean Patent Application No. 10-2025-0000526, filed January 2, 2025, 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.

[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 electrical energy.

[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] 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.

[0010] Therefore, there is a need for a secondary battery that has relatively few restrictions on shape while allowing for increased battery capacity.

[0011] The object of the present invention is to provide a secondary battery having fewer restrictions on shape, improved battery capacity, and capable of reducing the amount of moisture flowing in from the outside.

[0012] A secondary battery according to an embodiment of the present invention may include: an electrode assembly; an outer shell formed of a sheet so as to have an internal space accommodating the electrode assembly and an outer shell opening communicating the internal space with the outside; and a cap covering the outer shell opening. The cap may include an outer shell portion coupled to the outer shell portion; and a terminal portion arranged to cover the outer shell opening together with the outer shell portion, the terminal portion being exposed to the outside and the inside of the outer shell portion, respectively, and electrically connected to the electrode assembly at a portion exposed to the inside of the outer shell portion. The terminal portion may include a material having lower moisture permeability than a material included in the outer shell portion. An area where the terminal portion covers the outer shell opening may be 90% or more of an area where the cap covers the outer shell opening.

[0013] The terminal portion may include an exposed portion having one surface exposed to the outside of the outer portion; and a support portion connected to the exposed portion and having a contact surface facing the outer portion coupled to the inner surface of the outer portion.

[0014] The area of ​​the above contact surface may be 30% or more of the area of ​​the terminal portion covering the opening of the exterior material.

[0015] The area of ​​the above-mentioned exposed portion covering the exterior opening may be at least 50% of the area of ​​the above-mentioned cap covering the exterior opening.

[0016] The terminal portion may have a sum of an area of ​​the exposed portion covering the exterior opening and an area of ​​the contact surface that is 90% or more of an area of ​​the cap covering the exterior opening.

[0017] The above-mentioned exposed portion may include an outer member having a shape corresponding to a through hole formed in the outer member and exposed to the outside of the outer member; and a passage member extending inwardly from the edge of the outer member to pass through the through hole.

[0018] The support member may include a first member vertically connected to the passage member. The contact surface may be included in the first member.

[0019] The width of the above first member may be less than or equal to the width of the inner surface of the outer portion.

[0020] The outer portion may include a resin material having adhesiveness by heat, and the first member may include a metal material. The inner surface of the outer portion and the first member may be joined to each other by heat and pressure.

[0021] The inner surface of the outer portion and the first member can be joined to each other by an adhesive applied between the outer portion and the first member.

[0022] The support member may further include a second member extending from the first member toward the electrode assembly and electrically connected to the electrode assembly.

[0023] The above second member can be combined with the inner surface of the exterior material.

[0024] The outer portion may include a first cover portion that covers the first member from the outside of the outer portion; and a second cover portion that is disposed between the second member and the outer portion and is coupled to the outer portion, and extends from the first cover portion toward the electrode assembly.

[0025] The surface of the above first cover part facing the first member can be combined with the contact surface.

[0026] Since the secondary battery according to a preferred embodiment of the present invention does not have a process for forming an outer material, there are fewer restrictions on the shape in which the outer material accommodates the electrode assembly, the possibility of defects such as cracks occurring in the outer material is reduced, and the battery capacity can be improved.

[0027] 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.

[0028] Specifically, even if the usage time of the secondary battery is extended, corrosion due to moisture penetration is prevented, so the performance of the secondary battery can be maintained.

[0029] In addition, the structural stability of the secondary battery can be improved by the bonding relationship and arrangement form of the terminal portion and the external portion.

[0030] In addition, the sealing properties of the terminal and the outer portion can be efficiently maintained.

[0031] The effects according to the present invention are not limited to the contents exemplified above, and more diverse effects are included in this specification.

[0032] FIG. 1 is a perspective view schematically illustrating a secondary battery according to Example 1 of the present invention.

[0033] Figure 2 is an exploded perspective view schematically illustrating a secondary battery according to Example 1 of the present invention.

[0034] Figure 3 is an exploded perspective view schematically illustrating a cap of a secondary battery according to Example 1 of the present invention.

[0035] FIG. 4 is a cross-sectional view schematically illustrating a portion of a cross-section taken along line A-A' of FIG. 1 of a secondary battery according to Example 1 of the present invention.

[0036] Figure 5 is an exploded perspective view schematically illustrating a secondary battery according to Example 2 of the present invention.

[0037] Figure 6 is an exploded perspective view schematically illustrating a cap of a secondary battery according to Example 2 of the present invention.

[0038] Figure 7 is a cross-sectional view schematically illustrating a cap and a portion of an outer shell of a secondary battery according to Example 2 of the present invention.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] Example 1

[0043] 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.

[0044] A secondary battery (10) according to Example 1 of the present invention may include an electrode assembly (100), an outer casing (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.

[0045] 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.

[0046] 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.

[0047] Referring to FIG. 2, the secondary battery (10) according to Embodiment 1 of the present invention may include an outer case (200). The outer case (200) of the secondary battery (10) may be provided to surround a portion of the electrode assembly (100). Specifically, the outer case (200) may be provided to surround a cap (300) to be described later and the electrode assembly (100). More specifically, the outer case (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.

[0048] The outer covering (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 covering (200) may be arranged in a form that wraps around the side of the electrode assembly (100). In this case, one end and the other end of the outer covering (200) may be arranged in a form that wraps around the electrode assembly (100) by meeting each other.

[0049] With regard to the form in which one end and the other end of the outer material (200) meet each other, it is possible for one side of one end and the other side of the other end to be joined so as to be in contact with each other (see FIG. 2), and it is also possible for one side of one end and one side of the other end to be joined so as to be in contact with each other (see FIG. 5). This is merely an example, and the form in which one end and the other end of the outer material (200) are joined to form a space for accommodating the electrode assembly (100) may vary.

[0050] With respect to the method of joining one end and the other end of the exterior material (200), the one end and the other end of the exterior material (200) may be joined to each other by heat sealing or heat and pressure sealing. That is, the exterior material (200) may include a material having heat sealing properties. Specifically, the exterior material (200) may include a material that melts by heat and has adhesive properties. For example, the exterior material (200) 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) can have excellent mechanical properties such as tensile strength, rigidity, surface hardness, wear resistance, and heat resistance, as well as chemical properties such as corrosion resistance.

[0051] Meanwhile, the outer covering (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 covering (200) is arranged to wrap the electrode assembly (100) along the side of the electrode assembly (100), outer covering 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 covering (200) in a manner to cover the outer covering 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 covering (200) and the cap (300). That is, the cap (300) may be arranged to cover the outer covering opening.

[0052] As an example of a method of joining the cap (300) and the outer material (200), the cap (300) and the outer material (200) may be joined by welding. Specifically, the outer part (310) may include a metal material, and the outer material (200) may include a metal layer that can be joined to the outer part (310) by welding at a portion facing the outer part (310).

[0053] As another example of a method of joining the cap (300) and the outer material (200), the cap (300) and the outer material (200) may be joined by sealing. Specifically, the outer part (310) may include a resin material having adhesiveness by heat, and the outer material (200) may include a resin layer that can be joined to the outer part (310) by heat and pressure at a portion facing the outer part (310). Here, the resin layer may include a material having sealing properties by heat as described above.

[0054] 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.

[0055] On the other hand, in the secondary battery (10) according to Example 1 of the present invention, since the outer covering (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 covering (200) can be prevented, and the material and thickness of the outer covering (200) can be selected relatively freely. In addition, since the electrolyte injection and degassing processes can be performed through the cap (300), the outer covering (200) is not discarded, so the economic feasibility of the process can be improved.

[0056] 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.

[0057] FIG. 3 is an exploded perspective view schematically illustrating a cap (300) of a secondary battery (10) according to Embodiment 1 of the present invention, and FIG. 4 is a cross-sectional view schematically illustrating a portion of a cross-section taken along line A-A' of FIG. 1 of a secondary battery (10) according to Embodiment 1 of the present invention.

[0058] Referring to FIGS. 3 and 4, the cap (300) of the secondary battery (10) according to Embodiment 1 of the present invention may include an outer portion (310) and a terminal portion (320).

[0059] The outer portion (310) of the cap (300) may be coupled with the outer material (200). In addition, the terminal portion (320) of the cap (300) may be coupled with the outer portion (310) and may be provided to be exposed to the outer and inner sides of the outer portion (310), respectively. Here, the inner side of the outer portion (310) may refer to a part of the internal space formed by the cap (300) and the outer material (200), and the outer side of the outer portion (310) may refer to a space outside the cap (300) and the outer material (200). Meanwhile, a portion of the terminal portion (320) exposed to the inner side of the outer 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.

[0060] As an example of a configuration for improving the structural stability of the cap (300), the terminal portion (320) of the cap (300) according to Embodiment 1 of the present invention may have its movement away from the electrode assembly (100) restricted by the outer portion (310). In this regard, the terminal portion (320) of the cap (300) may include an exposed portion (322) and a support portion (321).

[0061] The exposed portion (322) of the terminal portion (320) may be provided to be exposed to the outside of the outer portion (310). Accordingly, the terminal portion (320) electrically connected to the electrode assembly (100) may be in electrical contact with the outside through the exposed portion (322) provided to be exposed to the outside of the outer portion (310). That is, the secondary battery (10) may provide electrical energy to the outside through the exposed portion (322).

[0062] Referring to FIG. 4, the exposed portion (322) of the terminal portion (320) may include an outer member (3221) and a passage member (3222).

[0063] The outer member (3221) of the exposed portion (322) may be exposed to the outside of the outer portion (310). That is, one side (S1) of the exposed portion (322) may be arranged to protrude from one side of the outer portion (310) in a direction away from the electrode assembly (100) (upward direction in FIG. 4). Alternatively, one side (S1) of the exposed portion (322) may be arranged to be located on the same plane as one side of the outer portion (310). Here, one side (S1) of the exposed portion (322) may be a side located at the outermost side of the exposed portion (322) and facing the outside of the outer portion (310).

[0064] Based on Fig. 4, one side (S1) of the exposed portion (322) can be the upper surface of the exposed portion (322), and one side of the external portion (310) can be the upper surface of the external portion (310).

[0065] With regard to a more specific shape of the outer member (3221), a through hole (H) may be formed in the outer member (310) for connection between the exposed portion (322) and the support portion (321).

[0066] The outer member (3221) may be formed in a shape corresponding to the through hole (H) of the outer portion (310). As a result, the outer member (3221) may protrude outwardly through the through hole (H) or be positioned within the through hole (H). That is, this shape may allow the outer member (3221) to be inserted into the through hole (H) from the inside of the outer portion (310) toward the outside of the outer portion (310) (upward direction in FIG. 4).

[0067] The passage member (3222) of the exposed portion (322) can extend from the edge of the outer member (3221) in the inward direction (downward direction in FIG. 4) of the outer portion (310) and pass through the through hole. Preferably, the passage member (3222) can be formed along the edge of the outer member (3221).

[0068] The pass-through member (3222) can define the perimeter of the exposed portion (322). The outer perimeter of the pass-through member (3222) can be in contact with or adjacent to the inner perimeter of the through hole (H). As a result, the terminal portion (320) and the outer portion (310) can be stably coupled to each other.

[0069] The support portion (321) of the terminal portion (320) is connected to the exposed portion (322), and can be supported by the outer portion (310) on the inside of the outer portion (310) to prevent the exposed portion (322) from being separated from the outer portion (310). Specifically, the support portion (321) can have a contact surface (S2) facing the outer portion (310) coupled to the inner surface of the outer portion (310).

[0070] With respect to the direction parallel to the penetration direction of the through hole (H), the support portion (321) may overlap with the outer portion (310). Therefore, the support portion (321) may be caught on the outer portion (310) so that the terminal portion (320) does not detach from the outer portion (310). That is, the support portion (321) may be supported by the outer portion (310). In addition, the contact surface (S2) of the support portion (321) may be coupled with the inner surface of the outer portion (310). Therefore, the structural stability of the cap (300) may be improved. In addition, the sealing property of the outer portion (310) and the terminal portion (320) may be improved.

[0071] As an example of a configuration for preventing moisture from penetrating from the outside to the inside of the cap (300), a ratio may be determined between the area where the terminal portion (320) according to Embodiment 1 of the present invention covers the exterior opening and the area where the cap (300) covers the exterior opening. Here, the area where the cap (300) covers the exterior opening may refer to an area projected by the cap (300) with respect to the opening direction of the exterior material (200). Similarly, the area where the terminal portion (320) covers the exterior opening may refer to an area projected by the terminal portion (320) with respect to the opening direction of the exterior material (200). More specifically, the area where the terminal portion (320) covers the exterior opening may refer to the sum of the area of ​​one surface (S1) of the exposed portion (322) and the area of ​​the contact surface (S2). For convenience of understanding, the area that the terminal portion (320) covers the outer opening is described below as 'S1+S2'.

[0072] The area (S1+S2) that the terminal portion (320) covers the exterior opening may be 90% or more of the area that the cap (300) covers the exterior opening.

[0073] Below, the method by which the area ratio of the terminal portion (320) and the cap (300) is derived is described in detail.

[0074] Water Vapor Transmission Rate (WVTR) is the amount of moisture infiltration (g) divided by the area (m 2) and time (h). Hydrogen fluoride (HF) may be generated inside the secondary battery (10) due to moisture penetrating into the secondary battery (10). HF may cause corrosion of the internal materials of the secondary battery (10). When the secondary battery (10) is used for 10 years at room temperature, there is a risk of corrosion of the internal materials of the secondary battery (10) when the concentration of HF generated inside is 10,000 ppm or more. Therefore, the area that the terminal part (320) covers the opening of the outer material can be set so that the concentration of HF is 10,000 ppm or less. Since the amount of moisture penetration can be calculated through the HF concentration, the area that the terminal part (320) covers the opening of the outer material can be obtained through the water vapor permeability. As a result of calculation in this way, the area where the terminal portion (320) covers the outer opening in order to prevent corrosion inside the secondary battery (10) may be 90% or more of the area where the cap (300) covers the outer opening.

[0075] The terminal portion (320) may include a material having lower moisture permeability than the material constituting the outer portion (310). Specifically, the terminal portion (320) may be composed of a material having lower moisture permeability than the material constituting the outer portion (310). Therefore, the outer portion (310) and the terminal portion (320) together cover the electrode assembly (100), thereby reducing the amount of moisture that permeates into the space in which the electrode assembly (100) is accommodated, compared to when the electrode assembly (100) is covered only with the outer portion (310). Preferably, the terminal portion (320) may be composed of metal.

[0076] Meanwhile, considering moisture penetration prevention and structural stability, the area where the exposed portion (322) covers the exterior opening may be 50% or more of the area where the cap (300) covers the exterior opening. Specifically, the area of ​​one side (S1) of the exposed portion (322) may be 50% or more of the area where the cap (300) covers the exterior opening. That is, the area where the outer member (3221) covers the exterior opening may be 50% or more of the area where the cap (300) covers the exterior opening.

[0077] With respect to the shape of the support member (321) supported by the outer member (310), the support member (321) may include a first member (3211) and a second member (3212).

[0078] The first member (3211) of the support member (321) can extend from the passage member (3222) in a direction (left-right direction in FIG. 4) orthogonal to the extension direction (up-down direction in FIG. 4) of the passage member (3222). That is, the first member (3211) can be connected to the passage member (3222) and formed perpendicular to the passage member (3222).

[0079] At this time, the first member (3211) may be arranged to be hung on the inner surface of the outer portion (310). With reference to Fig. 4, the inner surface of the outer portion (310) may mean the lower surface of the outer portion (310).

[0080] Additionally, the first member (3211) of the support member (321) may include a contact surface (S2). Specifically, one surface of the first member (3211) may be the contact surface (S2). As described above, the contact surface (S2) may be coupled to the outer member (310).

[0081] The area of ​​the contact surface (S2) may be 30% or more of the area (S1+S2) that the terminal portion (320) covers the outer material opening. As a result, sufficient sealing can be secured between the outer portion (310) and the terminal portion (320).

[0082] As an example of a configuration for securing sealing between the outer portion (310) and the terminal portion (320), the first member (3211) may extend from the passage member (3222) toward the outer material (200). Here, the width along which the first member (3211) extends may be smaller than or equal to the width of the inner surface of the outer portion (310). That is, the width (T1, T2) of the contact surface (S2) may be smaller than or equal to the width (T3, T4) of the inner surface of the outer portion (310) (see FIG. 3). Accordingly, the area of ​​the contact surface (S2) may be smaller than or equal to the area of ​​the inner surface of the outer portion (310).

[0083] At this time, the extension width (T1) of the first member (3211) connected to the second member (3212) and the extension width (T2) of the first member (3211) not connected to the second member (3212) may be different. However, each extension width (T1, T2) of the first member (3211) may be less than or equal to the width (T3, T4) of the inner surface of the outer portion (310). For reference, FIG. 4 illustrates an example in which the extension widths (T1, T2) of the first member (3211) are equal to the widths (T3, T4) of the inner surface of the outer portion (310).

[0084] Meanwhile, as an example of a method of joining the outer portion (310) and the first member (3211), joining by sealing is possible. The first member (3211) may include a metal material, and the outer portion (310) may include a resin material that has adhesive properties due to heat. Accordingly, the resin material of the outer portion (310) that has adhesive properties due to heat melts, and can be joined to the first member (3211) by pressure.

[0085] As another example of a method of joining the outer portion (310) and the first member (3211), the inner surface of the outer portion (310) and the first member (3211) may be joined to each other by an adhesive applied between the outer portion (310) and the first member (3211). Here, one surface of the first member (3211) joined to the inner surface of the outer portion (310) may be a contact surface (S2).

[0086] The second member (3212) of the support member (321) extends from the first member (3211) toward the electrode assembly (100), and one end thereof can be electrically connected to the electrode assembly (100). At this time, a plurality of second members (3212) may be formed. That is, the support member (321) can be electrically connected to the electrode assembly (100) at a plurality of locations. Accordingly, when the secondary battery (10) includes a plurality of electrode assemblies (100), the plurality of electrode assemblies (100) can be electrically connected to the second member (3212) arranged at a close location, respectively. Through this, the secondary battery (10) can efficiently increase the battery capacity.

[0087] For example, the second member (3212) of the support member (321) may be provided as a pair, each connected to the opposite corners of the first member (3211) (see FIG. 3). That is, the second member (3212) may be connected to the upper and lower corners of the first member (3211) with reference to FIG. 3. At this time, the second member (3212) extending from the upper and lower portions of the first member (3211) may be connected to two electrode tabs (110) arranged vertically, respectively.

[0088] However, this is only one example, and as another example, the second member (3212) of the support member (321) may be formed along the edge of the first member (3211). That is, the second member (3212) may be connected to all corners of the first member (3211).

[0089] Meanwhile, the second member (3212) may be combined with the exterior material (200). More specifically, the second member (3212) may be combined with the inner surface of the exterior material (200). As a result, the moisture penetration path formed between the support member (321) and the exterior material (200) may be lengthened, and the amount of moisture penetrating into the interior may be reduced.

[0090] Specifically, the second member (3212) may include a metal material, and the exterior material (200) may include a resin layer having heat-sensitive adhesiveness at a portion facing the second member (3212). Accordingly, the second member (3212) and the exterior material (200) may be joined by sealing using heat and pressure.

[0091] 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 outer portion (310) and the terminal portion (320). Depending on the material of the outer portion (310), moisture or the like on the outside of the outer portion (310) can penetrate into the inner portion of the outer portion (310) by penetrating the outer 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 outer portion (310) through which moisture can penetrate by covering the electrode assembly (100) together with the terminal portion (320) made of metal. In addition, since the support part (321) is arranged in a form supported by the outer part (310), the moisture penetration path formed between the support part (321) and the outer part (310) can be lengthened. In addition, since the support part (321) is combined with the outer material (200), the moisture penetration path formed between the support part (321) and the outer material (200) can be lengthened.

[0092] Therefore, the secondary battery (10) according to Example 1 of the present invention can reduce the phenomenon of problems occurring in the performance of the secondary battery (10) by reducing the amount of moisture penetrating into the interior.

[0093] Example 2

[0094] Fig. 5 is an exploded perspective view schematically illustrating a secondary battery (10') according to Embodiment 2 of the present invention, and Fig. 6 is an exploded perspective view schematically illustrating a cap (300') of the secondary battery (10') according to Embodiment 2 of the present invention. In addition, Fig. 7 is a cross-sectional view schematically illustrating a portion of a cap (300') and an outer material (200') of the secondary battery (10') according to Embodiment 2 of the present invention.

[0095] 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 outer material (200'), the shape of the outer portion (310'), the shape of the terminal portion (320'), the method of combining the configuration, etc.

[0096] In the secondary battery (10') according to Example 2 of the present invention, the area (S1+S2) where the terminal portion (320') covers the outer opening may be 90% or more of the area where the cap (300') covers the outer opening, similar to the secondary battery (10) according to Example 1.

[0097] Referring to FIG. 5, a secondary battery (10') according to Embodiment 2 of the present invention may include an electrode assembly (100), an outer case (200'), and a cap (300'). The outer case (200') of the secondary battery (10') may be provided to surround a portion of the electrode assembly (100). Specifically, the outer case (200') may be provided to surround the cap (300') and the electrode assembly (100). More specifically, the outer case (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.

[0098] With regard to the shape in which one end and the other end of the outer material (200') meet each other, one side of one end and one side of the other end can be joined so as to be in contact with each other (see Fig. 5).

[0099] Referring to Fig. 6, the second member (3212') of the support member (321') can be formed along the edge of the first member (3211). That is, the second member (3212') can be connected to the edge of the first member (3211) based on Fig. 6. The structural stability between the outer member (310') and the terminal member (320') can be improved by the shape of the second member (3212').

[0100] As an example of a configuration for improving the bonding strength with the terminal portion (320'), the outer portion (310') of the cap (300') according to Example 2 of the present invention may include a first cover portion (311) and a second cover portion (312).

[0101] Referring to Fig. 7, the first cover portion (311) may be provided to cover the first member (3211) from the outside of the outer portion (310'). That is, the first cover portion (311) may overlap the first member (311) in a direction parallel to the penetration direction of the through hole (H).

[0102] Additionally, the second cover portion (312) may extend from the first cover portion (311) in a direction toward the electrode assembly (100). Specifically, the second cover portion (312) may be positioned between the second member (3212') and the outer material (200'). More specifically, the second cover portion (312) may be formed along the edge of the first cover portion (311).

[0103] The first cover portion (311) can be joined with one surface of the first member (3211) at a surface facing the first member (3211). More specifically, the first cover portion (311) can be joined with the contact surface (S2) at a surface facing the contact surface (S2). That is, the inner surface of the first cover portion (311) can be joined with the contact surface (S2).

[0104] The second cover part (312) is disposed between the second member (3212') and the exterior material (200'), so that one side can be joined to the second member (3212') of the support part (321'), and the other side can be joined to the exterior material (200'). At this time, an adhesive (400) can be applied to join the second cover part (312) to the other components. That is, the adhesive (400) can be applied to one side and the other side of the second cover part (312). The second cover part (312) can be joined to the second member (3212') and the exterior material (200') through the adhesive (400). Preferably, an adhesive (400) is applied between the outer material (200') and the outer portion (310') so that the outer material (200') and the outer portion (310') can be joined to each other, and an adhesive (400) is applied between the outer portion (310') and the terminal portion (320' so that the outer portion (310') and the terminal portion (320') can be joined to each other. Here, the type and application form of the adhesive (400) for joining can be varied.

[0105] Meanwhile, the cap (300') according to Embodiment 2 of the present invention may be arranged such that one side of the terminal portion (320') is on the same plane as one side of the outer portion (310'). In this case, since there is no part of the terminal portion (320') that protrudes outward from the outer portion (310'), arrangement may be easy when arranging a plurality of secondary batteries (10').

[0106] 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.

[0107] [Explanation of symbols]

[0108] 10, 10': Secondary battery 100: Electrode assembly

[0109] 110: Electrode tab 200, 200': Sheath

[0110] 300, 300': Cap 310, 310': Outer part

[0111] 311: First cover part 312: Second cover part

[0112] 320, 320': Terminal part 321, 321': Support part

[0113] 322: Exposed area 400: Adhesive

[0114] 3211: First member 3212, 3212': Second member

[0115] 3221: Outer member 3222: Passing member

Claims

1. Electrode assembly; An outer material formed as a sheet having an internal space for accommodating the electrode assembly and an outer material opening for communicating the internal space with the outside; and Including a cap covering the above outer material opening, The above cap, An exterior part combined with the above exterior material; and It is arranged to cover the opening of the outer material together with the outer part, and is exposed to the outer and inner sides of the outer part, respectively, and includes a terminal part that is electrically connected to the electrode assembly at a part exposed to the inner side of the outer part. The above terminal portion includes a material having lower moisture permeability than the material included in the outer portion, A secondary battery, wherein the area of the terminal portion covering the outer opening is 90% or more of the area of the cap covering the outer opening.

2. In claim 1, The above terminal part, An exposed portion, one side of which is exposed to the outside of the outer portion; and A secondary battery comprising a support portion connected to the above-mentioned exposed portion and having a contact surface facing the outer portion joined to the inner surface of the outer portion.

3. In claim 2, A secondary battery, wherein the area of the above contact surface is 30% or more of the area of the terminal portion covering the opening of the outer material.

4. In claim 2, A secondary battery, wherein the area of the exposed portion covering the outer opening is 50% or more of the area of the cap covering the outer opening.

5. In claim 2, The above terminal part, A secondary battery, wherein the sum of the area of the exposed portion covering the outer opening and the area of the contact surface is 90% or more of the area of the cap covering the outer opening.

6. In claim 2, The above exposed part is, An outer member having a shape corresponding to the through hole formed in the outer part and exposed to the outside of the outer part; and A secondary battery including a passage member extending inwardly from the edge of the outer member and passing through the through hole.

7. In claim 6, The above support part, Including a first member vertically connected to the above-mentioned passage member, A secondary battery, wherein the above contact surface is included in the first member.

8. In claim 7, A secondary battery, wherein the width of the first absence is less than or equal to the width of the inner surface of the outer portion.

9. In claim 7, The above outer part includes a resin material that has adhesiveness by heat, The above first member comprises a metal material, A secondary battery, wherein the inner surface of the outer portion and the first member are joined to each other by heat and pressure.

10. In claim 7, A secondary battery, wherein the inner surface of the outer portion and the first member are joined to each other by an adhesive applied between the outer portion and the first member.

11. In claim 7, The above support part, A secondary battery further comprising a second member extending from the first member toward the electrode assembly and electrically connected to the electrode assembly.

12. In claim 11, The second member is a secondary battery that is bonded to the inner surface of the outer material.

13. In claim 11, The above outer part, A first cover part covering the first member from the outside of the outer part; and A secondary battery comprising a second cover part disposed between the second member and the outer casing, coupled with the outer casing, and extending from the first cover part toward the electrode assembly.

14. In claim 13, The above first cover part, A secondary battery, wherein a surface facing the first absence is combined with the contact surface.

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