Secondary battery and its manufacturing method, battery pack

Abstract

The present invention relates to a secondary battery that has fewer restrictions on shape, improved battery capacity, can reduce the amount of moisture that flows in from the outside, and has improved structural stability. The secondary battery according to the present invention includes an electrode assembly, an outer film surrounding a part of the electrode assembly, and a cap surrounding the remaining part of the electrode assembly, wherein the cap may include a connecting portion that is coupled to the outer film, a terminal portion that is partially embedded in the connecting portion, and an outer surface portion that covers at least a part of the outer surface of the terminal portion that faces outward from the electrode assembly.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application Nos. 10-2024-0104209 filed on August 5, 2024, 10-2024-0071802 filed on May 31, 2024, and 10-2023-0117851 filed on September 5, 2023, and all the contents disclosed in the documents of the Korean patent applications are incorporated herein by reference in their entirety.

[0002] The present invention relates to a secondary battery, and more particularly, to a secondary battery capable of charging and discharging, a method for manufacturing the same, and a battery pack.

Background Art

[0003] In recent years, with the rising price of energy sources due to the depletion of fossil fuels and the increasing concern about environmental pollution, the demand for environmentally friendly alternative energy sources has become an essential and indispensable factor for future life. Therefore, research on various power generation technologies such as solar power, wind power, and tidal power has continued, and significant attention has also been paid to power storage devices such as batteries for more efficiently using the electrical energy produced in this way.

[0004] In addition, as the technology development and demand for electronic mobile devices and electric vehicles using batteries increase, the demand for batteries as an energy source has been rapidly increasing, and thus, many studies on batteries that can meet various requirements have been conducted.

[0005] Batteries for storing electrical energy are generally classified into primary batteries and secondary batteries. A primary battery is a disposable consumable battery, whereas a secondary battery is a rechargeable battery manufactured using a material that can repeat the oxidation and reduction processes between current and substances. That is, when a reduction reaction of the material occurs due to current, the power source is charged, and when an oxidation reaction of the material occurs, the power source is discharged. By repeating such charging and discharging, electricity is generated.

[0006] Secondary batteries can be classified into cylindrical cells, pouch cells, and prismatic cells, depending on their form. Of these, pouch cells can be manufactured in which an electrode assembly, in which a positive electrode, negative electrode, and separator membrane are stacked inside a pouch, and the outside of the pouch is sealed.

[0007] Secondary batteries can be classified into cylindrical cells, pouch cells, and prismatic cells, depending on their form. Of these, pouch cells can be manufactured in which an electrode assembly, in which a positive electrode, negative electrode, and separator membrane are stacked inside a pouch, and the outside of the pouch is sealed.

[0008] Conventional pouch cells have a problem where cracks occur in the pouch film during the molding process, resulting in a large amount of pouch film being discarded after the degassing process. Furthermore, the molding depth is limited by the material properties of the pouch film, which in turn limits the increase in battery capacity.

[0009] Therefore, there is a need for a secondary battery that has relatively few shape restrictions and also offers improved battery capacity. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The object of the present invention is to provide a secondary battery that has fewer shape restrictions, improved battery capacity, reduced amount of moisture entering from the outside, and improved structural stability. [Means for solving the problem]

[0011] The secondary battery according to the present invention includes an electrode assembly, an outer film surrounding a part of the electrode assembly, and a cap surrounding the remaining part of the electrode assembly, wherein the cap may include a connecting portion that is coupled to the outer film, a terminal portion that is partially embedded in the connecting portion, and an outer surface portion that covers at least a part of the outer surface of the terminal portion that faces outward from the electrode assembly.

[0012] The terminal portion may include a first member exposed to the outside of the connecting portion and a second member extending from the first member toward the electrode assembly.

[0013] The outer surface portion may cover the outer surface of the first member.

[0014] The second member may be provided such that one end on the electrode assembly side is exposed to the inside of the connecting portion.

[0015] The second member may consist of multiple members, and at least one of the second members may be provided such that one end on the electrode assembly side is exposed to the inside of the connecting portion.

[0016] The secondary battery may further include a busbar positioned between the terminal portion and the electrode assembly, connecting one end of the second member exposed inside the connecting portion to the electrode assembly.

[0017] The second member may further include a third member that extends from the side of the first member toward the electrode assembly and is embedded in the connecting portion so as to be covered by the connecting portion, and the terminal portion extends from the first member toward the electrode assembly and is provided penetrating the connecting portion so as to be exposed on the inside of the connecting portion.

[0018] The secondary battery may further include a busbar positioned between the terminal portion and the electrode assembly, which connects the third member, exposed inside the connecting portion, and the electrode assembly.

[0019] The busbar 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.

[0020] The outer surface may have holes formed in it so that the outer surface of the terminal portion is exposed to the outside.

[0021] The terminal portion may include a terminal member that penetrates the outer surface portion.

[0022] An end portion of the terminal member may protrude outside the outer surface portion.

[0023] The terminal portion may be arranged such that one surface thereof protrudes in a direction away from the electrode assembly from one surface of the connecting portion.

[0024] At least a part of the terminal portion may be embedded in the connecting portion.

[0025] The terminal portion may include a first member exposed outside the connecting portion and a second member extending from the first member toward the electrode assembly and embedded in the connecting portion.

[0026] A method for manufacturing a secondary battery according to an embodiment of the present invention includes steps of providing an electrode assembly including a positive electrode and a negative electrode, surrounding a part of the electrode assembly with an exterior film, and covering the remaining part of the electrode assembly with a cap. The cap includes a connecting portion coupled to the exterior film, a terminal portion partially embedded in the connecting portion, and an outer surface portion covering at least a part of a surface facing the outside of the electrode assembly among outer surfaces of the terminal portion. At least a part of the terminal portion may be embedded in the connecting portion.

[0027] A battery pack according to an embodiment of the present invention may include a plurality of the aforementioned secondary batteries and a packaging that houses the plurality of secondary batteries.

Advantages of the Invention

[0028] A secondary battery according to a preferred embodiment of the present invention does not have a step of forming an exterior film. Therefore, there are few restrictions on the form in which the exterior film accommodates the electrode assembly, the possibility of defects such as cracks occurring in the exterior film is low, and the battery capacity can be improved.

[0029] Furthermore, by reducing the extent to which moisture and other substances penetrate from the outside of the secondary battery into the inside of the secondary battery, the safety of the secondary battery can be improved.

[0030] Furthermore, the busbar allows the terminal section to be electrically connected to the electrode assembly in various configurations.

[0031] Furthermore, the structural stability of the secondary battery can be improved by adjusting the coupling relationship and arrangement between the terminal and connecting parts.

[0032] Furthermore, the outer surface protects the terminals from external impacts and contamination.

[0033] Furthermore, by connecting the terminal portion and the connecting portion to each other, the coupling between the terminal portion and the connecting portion can be improved.

[0034] Furthermore, since the terminal portion is covered by the outer surface, the insulation between the terminal portion and other components can be improved, and heat propagation can be suppressed under thermal runaway conditions.

[0035] Furthermore, since the terminal portion is surrounded by the outer surface portion and the connecting portion, the cap can be easily manufactured using an insert injection molding process. At the same time, since at least a portion of the terminal portion is embedded in the connecting portion, the structural stability of the cap can be improved.

[0036] The effects of the present invention are not limited to those exemplified above, and a variety of other effects are included herein. [Brief explanation of the drawing]

[0037] [Figure 1] This is a schematic perspective view showing a secondary battery according to the first embodiment of the present invention. [Figure 2] This is a schematic exploded perspective view showing a secondary battery according to the first embodiment of the present invention. [Figure 3]This is a schematic cross-sectional view showing a cross-section obtained by cutting the cap of a secondary battery according to the first embodiment of the present invention along line A-A' in Figure 2. [Figure 4] Figure 3 is a schematic cross-sectional view showing a modified version of the cap. [Figure 5] This is a schematic cross-sectional view showing the cap and busbar of a secondary battery according to a second embodiment of the present invention. [Figure 6] Figure 5 is a schematic cross-sectional view showing a modified version of the cap. [Figure 7] Figure 3 is a schematic cross-sectional view showing other variations of the cap. [Figure 8] Figure 3 is a schematic cross-sectional view showing yet another variation of the cap. [Figure 9] This is an exploded perspective view schematically showing a battery pack according to the fifth embodiment of the present invention. [Modes for carrying out the invention]

[0038] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings, so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. However, the present invention can be realized in a variety of different forms and is not limited to or restricted to the following embodiments.

[0039] In order to clearly explain the present invention, detailed descriptions of parts unrelated to the description or related prior art that may obscure the gist of the invention have been omitted. In this specification, when assigning reference numerals to components in each drawing, the same or similar reference numerals are assigned to components that are the same or similar throughout the specification.

[0040] Furthermore, the terms and words used in this specification and the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather should be interpreted in a manner consistent with the technical concept of the present invention, in accordance with the principle that inventors can appropriately define the concepts of terms in order to best explain their invention.

[0041] First Embodiment Figure 1 is a schematic perspective view showing a secondary battery 10 according to the first embodiment of the present invention, and Figure 2 is a schematic exploded perspective view showing a secondary battery 10 according to the first embodiment of the present invention.

[0042] The secondary battery 10 according to the first embodiment of the present invention may include an electrode assembly 100, an outer film 200, and a cap 300. The components of the secondary battery 10 will be described in more detail below. The details of the first embodiment can also be applied to the embodiments described later, unless otherwise contradictory.

[0043] The electrode assembly 100 of the secondary battery 10 may include a positive electrode, a negative electrode, and a separator membrane. Here, the separator membrane is placed between the positive electrode and the negative electrode to physically separate them. The electrode assembly 100 may be in a form in which the positive electrode, negative electrode, and separator membrane are stacked, or in a jelly roll form in which the positive electrode, negative electrode, and separator membrane are wound up.

[0044] On the other hand, the electrode assembly 100 may include electrode tabs 110 connected to the electrodes. The electrode tabs 110 may be provided separately or as part of the current collector constituting the electrodes. If the electrode assembly 100 is an all-solid-state battery, a solid electrolyte may be provided instead of a separator membrane.

[0045] Referring to Figure 2, the secondary battery 10 according to the first embodiment of the present invention may include an outer film 200. The outer film 200 of the secondary battery 10 may be provided so as to surround a part of the electrode assembly 100. Specifically, the outer film 200 may be provided so as to surround the cap 300 and the electrode assembly 100, which will be described later. More specifically, the outer film 200 may be coupled with the cap 300 to form an internal space, and the electrode assembly 100 may be housed in the internal space.

[0046] To surround the electrode assembly 100, the outer film 200 may be made of a shape-deformable material. For example, the outer film 200 may be bent.

[0047] Furthermore, the outer film 200 may be made of a non-stretchable material. Conventionally, a pouch film was molded to form a space for housing the electrode assembly. However, since the outer film 200 does not need to be deformed by molding, it may be made of a non-stretchable material. In other words, the outer film 200 does not need to be stretchable.

[0048] The outer film 200 of the secondary battery 10 may have a shape in which a sheet or film is wound along the side surface of the electrode assembly 100. That is, the outer film 200 may be arranged in a manner that surrounds the side of the electrode assembly 100. Here, one end and the other end of the outer film 200 may be in contact with each other to surround the electrode assembly 100. In relation to the configuration in which one end and the other end of the outer film 200 are in contact with each other, it is possible to connect one surface of one end and the other surface of the other end so that they are in contact with each other (see Figure 2), and it is also possible to connect one surface of one end and the other surface of the other end so that they are in contact with each other. This is merely an example, and there are various configurations in which one end and the other end of the outer film 200 are connected to form a space for housing the electrode assembly 100.

[0049] In relation to the method by which one end of the outer film 200 is joined to the other, the one end of the outer film 200 may be joined to the other by heat sealing or by heat and pressure sealing. That is, the outer film 200 may contain a substance that has heat sealing properties. Specifically, the outer film 200 may contain a substance that melts and adheres when heated.

[0050] For example, the exterior film 200 may include a sealant layer, a barrier layer, and an insulating layer.

[0051] The sealant layer may contain one or more substances selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly(p-phenylenebenzobisoxazole), polyarylate, Teflon®, and glass fibers. Polyolefin resins such as polypropylene (PP) or polyethylene (PE) are mainly used. In particular, polypropylene (PP) has excellent mechanical properties such as tensile strength, rigidity, surface hardness, abrasion resistance, and heat resistance, as well as chemical properties such as corrosion resistance. The barrier layer may contain one or more substances selected from the group consisting of iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), aluminum (Al), stainless steel (SUS), and alloys.

[0052] The insulating layer may contain one or more substances selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly(p-phenylenebenzobisoxazole), polyarylate, Teflon®, and glass fibers.

[0053] Alternatively, the outer film 200 may be arranged so that it surrounds a portion of the electrode assembly 100, and the cap 300 surrounds the rest of the electrode assembly 100. Specifically, when the outer film 200 is arranged so as to surround the electrode assembly 100 along its side surface, outer openings may be formed at both ends of the electrode assembly 100. The cap 300 of the secondary battery 10 may be connected to the outer film 200 in such a way that it covers the outer openings at both ends of the electrode assembly 100, and the electrode assembly 100 may be housed in the internal space formed by the outer film 200 and the cap 300.

[0054] 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 in the portion facing the connecting portion 310 that is joined to the connecting portion 310 by welding.

[0055] Another example of a method of joining the cap 300 and the outer film 200 is that the cap 300 and the outer film 200 may be joined by a seal. Specifically, the connecting portion 310 may include a resin material that is heat-adhesive, and the outer film 200 may include a resin layer in the portion facing the connecting portion 310 that is bonded to the connecting portion 310 by heat and pressure. Here, the resin layer may include the aforementioned heat-sealing material.

[0056] Conventional pouch cells were constructed by molding a sheet or film to form a cup portion for housing the electrode assembly 100. During the molding process of the cup portion, the depth that could be molded was limited by the material properties of the sheet or film, and this also limited the capacity that could house the electrode assembly 100. Furthermore, when molding a sheet or film, the thickness is thinnest at the corners, which frequently resulted in defects such as cracks. In addition, conventional pouch cells required a gas collection section to collect gas in the degassing process to remove gas accumulated inside the pouch, and a large amount of the gas collection section was removed and discarded after the degassing process.

[0057] In contrast, the secondary battery 10 according to the first embodiment of the present invention allows the outer film 200 to be used in accordance with the volume of the electrode assembly 100, thus eliminating any limitations on the capacity that can accommodate the electrode assembly 100. Furthermore, since molding of the cup portion is not required, 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. At the same time, since the electrolyte injection and degassing processes can be performed using the cap 300, no discarded outer film 200 is generated, improving the economic efficiency of the process.

[0058] On the other hand, although not described in detail in this invention, the cap 300 may further include an electrolyte inlet for injecting the electrolyte, a gas outlet for discharging gas during the degassing process, and so on.

[0059] Figure 3 is a schematic cross-sectional view showing a portion of the cross-section obtained by cutting along line A-A' in Figure 2 of the secondary battery 10 according to the first embodiment of the present invention, and Figure 4 is a schematic cross-sectional view showing a modified example of the cap 300 according to Figure 3.

[0060] Referring to Figure 3, the cap 300 of the secondary battery 10 according to the first embodiment of the present invention may include a connecting portion 310 and a terminal portion 320.

[0061] The connecting portion 310 of the cap 300 may be connected to the outer film 200. The terminal portion 320 of the cap 300 may also be connected to the connecting portion 310 and provided to be exposed on both the outside and inside of the connecting portion 310, respectively. Here, the inside of the connecting portion 310 can mean a part of the internal space formed by the cap 300 and the outer film 200, and the outside of the connecting portion 310 can mean the external space of the cap 300 and the outer film 200. On the other hand, the portion of the terminal portion 320 exposed on the inside of the connecting portion 310 may be electrically connected to the electrode assembly 100. Here, the electrical connection includes both a direct connection between the terminal portion 320 and the electrode assembly 100 and an indirect connection mediated by another electrically conductive member.

[0062] On the other hand, as an example of a method of 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 becomes adhesive when heated. In this case, the resin material of the heat-adhesive connecting portion 310 melts and is joined to the terminal portion 320 by pressure.

[0063] As an example of a configuration to improve the structural stability of the cap 300, the terminal portion 320 of the cap 300 according to the first embodiment of the present invention may be embedded in the connecting portion 310 in at least a part thereof. In connection with this, the terminal portion 320 of the cap 300 may include a first member 321 and a second member 322.

[0064] The first member 321 of the terminal portion 320 may be provided such that a portion of it is exposed to the outside of the connecting portion 310. Therefore, the terminal portion 320, which is electrically connected to the electrode assembly 100, can make electrical contact with the outside via the first member 321 which is provided to be exposed to the outside of the connecting portion 310. In other words, the secondary battery 10 can provide electrical energy to the outside via the first member 321.

[0065] The second member 322 of the terminal portion 320 may extend toward the electrode assembly 100. That is, the second member 322 may extend toward the electrode assembly 100 from the first member 321. Specifically, the second member 322 may be provided such that one end on the electrode assembly 100 side is exposed inside the connecting portion 310. Here, the inside of the connecting portion 310 can mean a part of the internal space formed by the outer film 200 and the cap 300.

[0066] Referring to Figure 3, the second member 322 of the terminal portion 320 may consist of multiple members. Furthermore, at least one of the second members 322 may be provided such that one end on the electrode assembly 100 side is exposed inside the connecting portion 310. Specifically, of the multiple second members 322 extending from the first member 321 toward the electrode assembly 100, some may be embedded in the connecting portion 310, and some may be exposed inside the connecting portion 310. Using Figure 3 as a reference, the second member 322 shown on the left is embedded in the connecting portion 310, while the second member 322 shown on the right is exposed inside the connecting portion 310.

[0067] The second member 322, which extends inside 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 includes both a direct connection between the second member 322 and the electrode assembly 100 and an indirect connection mediated by another electrically conductive member.

[0068] When the second member 322 and the electrode assembly 100 are directly connected, the electrode tabs 110 of the electrode assembly 100 may be connected to the second member 322. Alternatively, when the second member 322 and the electrode assembly 100 are indirectly connected, the secondary battery 10 may include a busbar 400 as an example of an intermediary electrically conductive member.

[0069] The busbar 400 is positioned between the terminal portion 320 and the electrode assembly 100, and may connect one end of the second member 322, which is exposed inside the connecting portion 310, to the electrode assembly 100. The busbar 400 may be made of metal to have electrical conductivity. Furthermore, the busbar 400 can be arranged in various forms depending on the length to which the second member 322 extends. Figure 3 shows a case in which the busbar 400 according to the first embodiment of the present invention has a substantially plate or rod shape.

[0070] On the other hand, according to a modified version of the first embodiment of the present invention, the second members 322 may all be provided such that one end on the electrode assembly 100 side is exposed inside the connecting portion 310. Specifically, multiple second members 322 extending from the first member 321 toward the electrode assembly 100 may all be exposed inside the connecting portion 310.

[0071] As described above, when the second member 322 and the electrode assembly 100 are directly connected, the electrode tabs 110 of the electrode assembly 100 may be connected to the second member 322. Also, when the second member 322 and the electrode assembly 100 are indirectly connected, the secondary battery 10 may include a plurality of busbars 400 as an example of an intermediary electrically conductive member.

[0072] Referring to Figure 4, in the modified secondary battery 10, the multiple busbars 400 may each be connected to the second member 322 inside the connecting portion 310. In that case, the electrode assembly 100 may be electrically connected to the second member 322 at multiple locations. Therefore, when the secondary battery 10 includes multiple electrode assemblies 100, the multiple electrode assemblies 100 may each be electrically connected to busbars 400 located in close proximity to each other. This allows the secondary battery 10 to efficiently increase its battery capacity.

[0073] On the other hand, in the cap 300 according to the first embodiment of the present invention, one surface of the terminal portion 320 may be arranged so as to protrude from one surface of the connecting portion 310 in a direction away from the electrode assembly 100. Specifically, one surface of the first member 321 may be arranged so as to protrude outside the connecting portion 310 beyond one surface of the connecting portion 310. Using Figure 3 or Figure 4 as a reference, one surface of the first member 321 and one surface of the connecting portion 310 can mean their respective upper surfaces. In that case, it is easy for the object from which electrical energy is to be obtained to come into contact with the protruding first member 321.

[0074] Another example of the arrangement of the first member 321 is that one surface of the first member 321 may be placed on the same plane as one surface of the connecting portion 310. In this case, since there is no part of the first member 321 that protrudes outside the connecting portion 310, it is easy to arrange multiple secondary batteries 10.

[0075] In the cap 300 of the secondary battery 10 according to the first embodiment of the present invention, the connecting portion 310 and the terminal portion 320, at least a part of which is embedded in the connecting portion 310, may cover the electrode assembly 100. Depending on the material of the connecting portion 310, moisture on the outside of the connecting portion 310 may permeate through the connecting portion 310 and penetrate to the inside of the connecting portion 310. Moisture penetration can cause malfunctions in the secondary battery 10. In the cap 300 of the secondary battery 10 according to the first embodiment of the present invention, the terminal portion 320, which is made of metal, covers the electrode assembly 100 together with the connecting portion 310, thereby reducing the area of ​​the connecting portion 310 that moisture can penetrate. Furthermore, since at least a part of the terminal portion 320 is embedded in the connecting portion 310, the moisture penetration path formed between the terminal portion 320 and the connecting portion 310 can be made less permeable to moisture. Therefore, the secondary battery 10 according to the first embodiment of the present invention can reduce the amount of moisture that penetrates into the interior, thereby reducing the phenomenon of problems occurring in the performance of the secondary battery 10.

[0076] Furthermore, in the cap 300 of the secondary battery 10 according to the first embodiment of the present invention, the second member 322 of the terminal portion 320 may be arranged in a state where it is embedded in the connecting portion 310. Thus, the connecting portion 310 restricts the movement of the terminal portion 320 and prevents the terminal portion 320 from detaching, thereby improving the structural stability of the secondary battery 10.

[0077] Although not described in detail in the first embodiment of the present invention, the cap 300 may further include a gas discharge member (not shown) for discharging gas from inside the secondary battery 10, a venting member (not shown) for guiding venting to occur in a specific direction, and so on.

[0078] Second Embodiment Figure 5 is a schematic cross-sectional view showing the cap 300' and busbar 400' of a secondary battery 10 according to a second embodiment of the present invention, and Figure 6 is a schematic cross-sectional view showing a modified example of the cap 300' according to Figure 5.

[0079] The following description will omit detailed explanations of the configuration identical to that of the secondary battery 10 according to the first embodiment of the present invention, and will focus on the differences. The secondary battery 10 according to the second embodiment of the present invention differs from the secondary battery 10 according to the first embodiment in the shape of the terminal portion 320', the shape of the busbar 400', the configuration coupling method, etc.

[0080] The secondary battery 10 according to the second embodiment 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 so as to surround a part of the electrode assembly 100. Specifically, the outer film 200 may be provided so as to surround the cap 300 and the electrode assembly 100. More specifically, the outer film 200 may be coupled with the cap 300 to form an internal space, in which the electrode assembly 100 may be housed.

[0081] The cap 300' of the secondary battery 10 may include a connecting portion 310 and a terminal portion 320'. The connecting portion 310 of the cap 300' may be connected to the outer film 200, and the terminal portion 320' of the cap 300 may be connected to the connecting portion 310 and provided to be exposed on the outside and inside of the connecting portion 310, respectively. Here, the inside of the connecting portion 310 can mean a part of the internal space formed by the cap 300' and the outer film 200, and the outside of the connecting portion 310 can mean the external space of the cap 300' and the outer film 200. On the other hand, the portion of the terminal portion 320' that is exposed on the inside of the connecting portion 310 may be electrically connected to the electrode assembly 100.

[0082] 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 the second embodiment of the present invention may further include a third member 323.

[0083] Referring to Figure 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 penetrating the connecting portion 310 so as to be exposed on the inside of the connecting portion 310. Preferably, the third member 323 has a shape that extends toward the electrode assembly 100 from the center of the surface of the first member 321 facing the electrode assembly 100. Depending on the shape of the third member 323, the busbar 400' described later can be arranged in various forms, and the contact area between the third member 323 and the busbar 400' can be increased to improve structural stability.

[0084] On the other hand, since the third member 323 is electrically connected to the electrode assembly 100, the second member 322 may be arranged in a form that is entirely embedded in the connecting portion 310. Here, the second member 322 may extend from the side of the first member 321 toward the electrode assembly 100. It is preferable that the second member 322 is formed along the edge of the first member 321. Since the second member 322 formed along the edge of the first member 321 is arranged in a state where it is entirely embedded in the connecting portion 310, the structural stability of the cap 300' can be improved. In that case, a path is formed between the connecting portion 310 and the terminal portion 320 that is relatively impervious to moisture penetration, and the penetration of moisture toward the interior of the secondary battery 10 can be efficiently prevented. This is just one example, and the second member 322 may be formed only at a pair of opposing corners of the four corners of the first member 321, which has a substantially rectangular cross-section.

[0085] As an example of a configuration for electrically connecting the third member 323 and the electrode assembly 100, the secondary battery 10 according to the second embodiment of the present invention may further include a busbar 400'. Specifically, the busbar 400' may be positioned between the terminal portion 320' and the electrode assembly 100, connecting the third member 323, which is exposed inside the connecting portion 310, and the electrode assembly 100 to each other.

[0086] As an example of a configuration for efficient connection with the third member 323, the busbar 400' according to the second embodiment 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.

[0087] Referring to Figure 5, the first metal part 410 may be in contact with the third member 323. For example, the first metal part 410 may have a substantially plate shape and extend parallel to the extending direction of the first member 321. Alternatively, the first metal part 410 may be positioned so that the surface facing the third member 323 is in contact with the third member 323. Here, the third member 323 includes a metal material, and the third member 323 and the first metal part 410 may be joined to each other by welding.

[0088] The second metal part 420 may extend from the first metal part 410 toward the electrode assembly 100. Here, the second metal part 420 may extend in a direction substantially perpendicular to the extending direction of the first metal part 410.

[0089] The third metal part 430 may extend from the second metal part 420 toward the outer film 200. Here, the third metal part 430 may extend in a direction substantially perpendicular to the extending direction of the second metal part 420. Specifically, the third metal part 430 may extend in a direction away from the third member 323.

[0090] The fourth metal part 440 may extend from the third metal part 430 toward the electrode assembly 100. Alternatively, one end of the fourth metal part 440 may be connected to the electrode assembly 100. Specifically, one end of the fourth metal part 440 may be connected to the electrode tab 110 of the electrode assembly 100.

[0091] The busbar 400', which includes the first metal part 410, the second metal part 420, the third metal part 430, and the fourth metal part 440, can be changed to various shapes depending on the number, arrangement, and form of the electrode assemblies 100.

[0092] Referring to Figure 6, the busbar 400' according to a modification of the second embodiment of the present invention may consist of a first metal part 410 and a second metal part 420. Here, one end of the second metal part 420 may be connected to the electrode assembly 100. In that case, the busbar 400' may be arranged in the space formed inside the connecting part 310 by the connecting part 310. Therefore, the space efficiency is improved when the electrode assembly 100 is arranged, and the battery capacity is increased.

[0093] On the other hand, an adhesive 500 may be used as a component for joining the connecting portion 310 and the terminal portion 320'. That is, the connecting portion 310 and the terminal portion 320' may be joined together by an adhesive 500 applied between them. Also, the connecting portion 310 and the outer film 200 may be joined together by an adhesive 500 applied between them. Here, the type and application form of the adhesive 500 for joining can vary. It is preferable that the adhesive 500 is composed of a substance with relatively high hydrophobicity.

[0094] Third Embodiment Figure 7 is a schematic cross-sectional view showing the cap 300 and busbar 400 of a secondary battery according to a third embodiment of the present invention. The connecting portion 310, terminal portion 320, and busbar 400 of the cap 300 according to this embodiment may be configured identically to the connecting portion, terminal portion, and busbar of the embodiment shown in Figure 3.

[0095] Referring to Figure 7, in this embodiment, the cap 300 may further include an outer surface portion 330. The outer surface portion 330 is configured to cover the surface of the terminal portion 320 that faces outward from the electrode assembly (hereinafter referred to as the outward-facing surface). This protects the outward-facing surface of the terminal portion 320 from external impacts and contamination.

[0096] Here, the outer surface portion 330 may be connected to the connecting portion 310. In other words, the outer surface portion 330 may be provided integrally with the connecting portion 310. The outer surface portion 330 may be made of the same material as the connecting portion 310. This can improve the coupling between the terminal portion 320 and the connecting portion 310.

[0097] On the other hand, in this embodiment, the outer surface portion 330 may cover at least a part of the outward-facing surface. Here, covering at least a part of the surface includes covering one region of the surface and covering the entire surface.

[0098] In this embodiment, the outward-facing surface may be provided on the first member 321. With reference to Figure 7, the outward-facing surface may be the surface facing upward on the outer surface of the first member 321. In such an embodiment, the outer surface portion 330 may cover the entire upper surface of the first member 321.

[0099] On the other hand, the electrode assembly can conduct electricity to the outside through the terminal portion 320. For this purpose, a predetermined hole 331 may be formed in the outer surface portion 330. In this embodiment, the outward-facing surface of the first member 321 may be exposed to the outside through the hole 331. Here, the portion exposed to the outside may be a region of the outward-facing surface. As a result, the external terminal can conduct electricity to the terminal portion 320 by being inserted into the hole 331.

[0100] Thus, in this embodiment, since the outward-facing surface is covered by the outer surface portion 330, not only is durability and coupling improved, but insulation between the terminal portion and other components can also be improved, and heat propagation can be suppressed in thermal runaway situations.

[0101] Furthermore, in this embodiment, since the terminal portion 320 made of metal material is surrounded by the outer surface portion 330 and the connecting portion 310, the cap 300 can be easily manufactured in an insert injection process. This improves the productivity of the secondary battery, simplifies the manufacturing process, and reduces manufacturing costs.

[0102] Fourth Embodiment Figure 8 is a schematic cross-sectional view showing the cap 300 and busbar 400 of a secondary battery according to the fourth embodiment of the present invention. The connecting portion 310, terminal portion 320, outer surface portion 330 of the cap 300, the first member 321 and second member 322 of the terminal portion 320, and the busbar 400 according to this embodiment may be configured identically to the connecting portion, terminal portion, outer surface portion, first member and second member of the terminal portion, and busbar of the third embodiment shown in Figure 7.

[0103] Referring to Figure 8, the terminal portion 320 may further include a terminal member 324. In this 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.

[0104] In this embodiment, the terminal member 324 may pass through the hole 331 in the outer surface portion 330. The end of the terminal member 324 may protrude to the outside of the outer surface portion 330. This allows the external terminal to be electrically connected to the terminal member 324.

[0105] Fifth Embodiment Figure 9 is an exploded perspective view schematically showing a battery pack 1 according to the fifth embodiment of the present invention. The battery pack 1 according to the fifth embodiment of the present invention may include a plurality of secondary batteries 10. The battery pack 1 may also include a package 20 that houses the plurality of secondary batteries 10 inside. Here, the secondary batteries 10 may be secondary batteries according to any one of the first to fourth embodiments described above.

[0106] The packaging 20 can take various forms. For example, the packaging 20 may include busbars electrically connected to multiple secondary batteries 10. Here, the packaging 20 may further include a busbar frame for securing the busbars. The number of secondary batteries 10 housed inside the packaging 20 varies depending on the battery pack 1.

[0107] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the equivalent scope of the technical concept of the present invention and the appended claims by persons with ordinary skill in the art to which the present invention pertains. [Explanation of Symbols]

[0108] 1 Battery Pack 10 Secondary battery 20 Packaging 100 electrode assembly 110 Electrode Tabs 200 Exterior Film 300, 300' cap 310 Connection section 320, 320' terminal section 321 First Member 322 Second Member 323 Third Member 324 Terminal component 330 External part 331 hole 400, 400' bus bar 410 1st metal part 420 2nd metal part 430 Third metal part 440 4th Metal Section 500 Adhesives

Claims

1. Electrode assembly and An outer film surrounding a part of the electrode assembly, Includes a cap that covers the remaining part of the electrode assembly, The aforementioned cap is A connecting portion that is joined to the outer film, A terminal portion, part of which is embedded in the aforementioned connecting portion, A secondary battery, comprising an outer surface portion that covers at least a part of the outer surface of the terminal portion that faces outward from the electrode assembly.

2. The aforementioned terminal portion is The first member exposed to the outside of the connecting portion, The secondary battery according to claim 1, further comprising a second member extending from the first member toward the electrode assembly.

3. The secondary battery according to claim 2, wherein the outer surface portion covers the outer surface of the first member.

4. The second member is, The secondary battery according to claim 2, wherein one end of the electrode assembly is provided so as to be exposed to the inside of the connecting portion.

5. The secondary battery according to claim 4, further comprising a busbar disposed between the terminal portion and the electrode assembly, which connects one end of the second member exposed on the inside of the connecting portion to the electrode assembly.

6. The second member 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 aforementioned terminal portion is The secondary battery according to claim 2, further comprising a third member extending from the first member toward the electrode assembly and provided through the connecting portion so as to be exposed on the inside of the connecting portion.

7. The secondary battery according to claim 6, further comprising a busbar disposed between the terminal portion and the electrode assembly, which connects the third member exposed on the inside of the connecting portion and the electrode assembly to each other.

8. The aforementioned busbar is The first metal part that contacts the third member, The secondary battery according to claim 7, further 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. The secondary battery according to claim 1, wherein a hole is formed in the outer surface so that the outer surface of the terminal portion is exposed to the outside.

10. The aforementioned terminal portion is The secondary battery according to claim 1, comprising a terminal member that penetrates the aforementioned outer surface portion.

11. The end of the terminal member protrudes outward from the outer surface portion, as described in claim 10.

12. The aforementioned terminal portion is The secondary battery according to claim 1, wherein one surface is arranged to protrude from one surface of the connecting portion in a direction away from the electrode assembly.

13. The aforementioned terminal portion is The secondary battery according to claim 1, wherein at least a portion of it is embedded in the connecting portion.

14. The aforementioned terminal portion is The first member exposed to the outside of the connecting portion, The secondary battery according to claim 13, further comprising a second member extending from the first member toward the electrode assembly and embedded in the connecting portion.

15. The steps include providing an electrode assembly including a positive electrode and a negative electrode, A step of surrounding a part of the electrode assembly with an outer film, The step includes covering the remaining part of the electrode assembly with a cap, The aforementioned cap is A connecting portion that is joined to the outer film, A terminal portion, part of which is embedded in the aforementioned connecting portion, A method for manufacturing a secondary battery, comprising an outer surface portion that covers at least a portion of the outer surface of the terminal portion that faces outward from the electrode assembly.

16. A plurality of secondary batteries according to claim 1, A battery pack, including a package for housing the plurality of secondary batteries.

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