Secondary battery, method for preparing secondary battery, and battery pack

Abstract

The present invention relates to a secondary battery having improved battery capacity, capable of reducing the amount of moisture introduced from the outside, and having improved structural stability while having less limitation in shape. A secondary battery according to the present invention comprises: an electrode assembly; an outer film surrounding a portion of the electrode assembly; and a cap surrounding the remaining portion of the electrode assembly. The cover includes: a connection portion coupled to the outer membrane; and a terminal portion coupled to the connection portion, exposed to an inner side and an outer side of the connection portion, and electrically connected to the electrode assembly at a portion exposed to the inner side of the connection portion. At least a portion of the terminal portion may be embedded in the connection portion.

Description

Technical Field

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2023-0117851, filed on September 5, 2023, and Korean Patent Application No. 10-2024-0071802, filed on May 31, 2024, the disclosures of which are incorporated herein by reference. Technical Field

[0004] This invention relates to secondary batteries, and more specifically, to secondary batteries capable of being charged and discharged, methods for preparing such secondary batteries, and battery packs. Background Technology

[0005] In recent years, due to the depletion of fossil fuels, energy prices have risen, concerns about environmental pollution have increased significantly, and the demand for eco-friendly alternative energy sources is becoming an indispensable factor in future life. Therefore, research on various power generation technologies such as solar, wind, and tidal power continues, and energy storage devices such as batteries for more efficient use of generated electricity are also receiving considerable attention.

[0006] Furthermore, with technological advancements and the increasing demand for battery-powered electronic mobile devices and electric vehicles, the demand for batteries as an energy source is rapidly increasing. Consequently, extensive research has been conducted on batteries capable of meeting diverse needs.

[0007] Batteries that store electrical energy can generally be divided into primary batteries and secondary batteries. Primary batteries are disposable, consumable batteries. Secondary batteries, on the other hand, are rechargeable batteries made using materials in which oxidation and reduction processes between current and materials are repeatable. That is, the power source is charged when a reduction reaction is performed on the material by an electric current, and discharged when an oxidation reaction is performed on the material by an electric current. This charge-discharge cycle is repeated to generate electricity.

[0008] Secondary batteries can be classified into cylindrical cell batteries, pouch cells, and prismatic cell batteries based on their shape. Among them, the pouch cell battery is manufactured by housing an electrode assembly in the form of a stack of positive electrode, negative electrode, separator, etc., inside a pouch-shaped component and then sealing the outer part of the pouch-shaped component.

[0009] Secondary batteries can be classified into cylindrical cell batteries, pouch cells, and prismatic cell batteries based on their shape. Among them, the pouch cell battery is manufactured by housing an electrode assembly in the form of a stack of positive electrode, negative electrode, separator, etc., inside a pouch-shaped component and then sealing the outer part of the pouch-shaped component.

[0010] According to related technologies, pouch cell batteries may have limitations in the molding process of the pouch film, which can lead to cracks, and the pouch film may be discarded after degassing. Furthermore, the plastic depth is limited due to the material properties of the pouch film, thus limiting the increase in battery capacity.

[0011] Therefore, there is a need for a secondary battery that can increase battery capacity while having relatively few restrictions on shape. Summary of the Invention

[0012] Technical issues

[0013] One aspect of the present invention provides a secondary battery in which the battery capacity is increased, while the shape is less restricted, the amount of moisture introduced from the outside is reduced, and the structural stability is improved.

[0014] Technical solution

[0015] According to one aspect of the invention, a secondary battery is provided, the secondary battery comprising: an electrode assembly; an outer membrane configured to surround a portion of the electrode assembly; and a cover configured to cover the remainder of the electrode assembly, wherein the cover includes: a connecting portion coupled to the outer membrane; and a terminal portion coupled to the connecting portion, exposed to each of an inner and outer side of the connecting portion, and electrically connected to the electrode assembly at a portion of the terminal portion exposed to the inner side of the connecting portion, wherein at least a portion of the terminal portion is embedded in the connecting portion.

[0016] The terminal portion may include: a first member exposed on the outside of the connection portion; and a second member extending from the first member toward the electrode assembly.

[0017] The second component can be configured such that one end of the electrode assembly is exposed inside the connection portion.

[0018] The second member can be configured in multiple ways, and at least one second member can be configured such that one end of the electrode assembly is exposed to the inside of the connection portion.

[0019] The secondary battery may also include a busbar disposed between the terminal portion and the electrode assembly to connect one end of the second member exposed inside the connection portion to the electrode assembly.

[0020] The second member may extend from the side portion of the first member toward the electrode assembly and be embedded in the connection portion to be covered by the connection portion, and the terminal portion may also include a third member that extends from the first member toward the electrode assembly and is configured to pass through the connection portion to be exposed inside the connection portion.

[0021] The secondary battery may also include a busbar disposed between the terminal portion and the electrode assembly to connect a third component exposed inside the connection portion to the electrode assembly.

[0022] The busbar may include: a first metal portion that contacts a third member; and a second metal portion that extends from the first metal portion toward the electrode assembly, and one end of the second metal portion is connected to the electrode assembly.

[0023] The busbar may include: a first metal portion that contacts a third member; a second metal portion that extends from the first metal portion toward an electrode assembly; a third metal portion that extends from the second metal portion toward an outer membrane; and a fourth metal portion that extends from the third metal portion toward the electrode assembly, with one end of the fourth metal portion connected to the electrode assembly.

[0024] The third component may include metallic material, and the third component and the busbar may be connected to each other by welding.

[0025] The terminal portion can be configured such that one surface of the terminal portion protrudes from one surface of the connection portion in a direction away from the electrode assembly.

[0026] In the cover, one surface of the connecting portion can be set on the same surface as one surface of the terminal portion.

[0027] The terminal portion may include a metallic material, the connecting portion may include a resin material that has adhesive properties when heated, and the terminal portion and the connecting portion may be joined together by heating and pressure.

[0028] In a secondary battery, the connecting parts and the terminal parts can be joined together by an adhesive applied between the connecting parts and the terminal parts.

[0029] The connecting portion may include a metallic material, and the outer membrane may include a metallic layer that is welded to the connecting portion.

[0030] The outer membrane may include a sealant layer with adhesive properties that can be bonded by heating, and a barrier layer comprising a metal, wherein the barrier layer may include one or more materials selected from the group consisting of iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), aluminum (Al), stainless steel (STS), and alloys thereof. The connecting portion may include a resin material with adhesive properties that can be bonded by heating, and the outer membrane may include a resin layer bonded to the connecting portion by heating and pressure.

[0031] In a secondary battery, the outer membrane and the connecting parts can be joined together by an adhesive applied between the outer membrane and the connecting parts.

[0032] The outer membrane may include a flexible membrane.

[0033] The outer membrane may include a flexible membrane that is not elastic.

[0034] According to another aspect of the present invention, a method for preparing a secondary battery is provided, the method comprising: providing an electrode assembly including a positive electrode and a negative electrode; such that an outer membrane surrounds a portion of the electrode assembly; and such that a cover covers the remainder of the electrode assembly, wherein the cover includes: a connecting portion coupled to the outer membrane; and a terminal portion coupled to the connecting portion, exposed to each of an inner and outer side of the connecting portion, and electrically connected to the electrode assembly at a portion of the inner side of the connecting portion, wherein at least a portion of the terminal portion is embedded in the connecting portion.

[0035] According to another aspect of the present invention, a battery pack is provided, the battery pack comprising: the aforementioned secondary batteries, wherein the secondary batteries are configured as a plurality; and a package configured to accommodate the plurality of secondary batteries.

[0036] Beneficial effects

[0037] In the secondary battery according to an embodiment of the present invention, since there is no process for molding an outer membrane, the limitation on the form in which the outer membrane accommodates the electrode assembly can be small, and the possibility of defects such as cracks in the outer membrane can be reduced, thereby improving the battery capacity.

[0038] In addition, it can reduce the degree to which moisture seeps from the outside of the secondary battery into the secondary battery, thereby improving the safety of the secondary battery.

[0039] In addition, the terminal section can be electrically connected to the electrode assembly in various forms via busbars.

[0040] In addition, the structural stability of the secondary battery can be improved by the connection relationship and arrangement of the terminal part and the connecting part.

[0041] In addition, since at least a portion of the terminal portion is embedded in the connecting portion, the structural stability of the cover can be improved.

[0042] The effects of the present invention are not limited to those described above, and therefore, this specification relates to many more different effects. Attached Figure Description

[0043] Figure 1 This is a schematic perspective view of a secondary battery according to Embodiment 1 of the present invention;

[0044] Figure 2 This is a schematic exploded perspective view of a secondary battery according to Embodiment 1 of the present invention;

[0045] Figure 3 The illustration shows the path along the path according to Embodiment 1 of the present invention. Figure 2 A schematic cross-sectional view of the cover of the secondary battery taken by line A-A';

[0046] Figure 4 It's a diagram. Figure 3 A schematic cross-sectional view of a modified example of the cover;

[0047] Figure 5 This is a schematic cross-sectional view illustrating the cover and busbar of a secondary battery according to Embodiment 2 of the present invention;

[0048] Figure 6 It's a diagram. Figure 5 A schematic cross-sectional view of a modified example of the lid; and

[0049] Figure 7 This is a schematic exploded perspective view of a battery pack according to Embodiment 3 of the present invention. Detailed Implementation

[0050] Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings, enabling those skilled in the art to readily implement the invention. However, the invention can be implemented in several different forms and is not limited to or construed as described below.

[0051] To clearly explain the invention, detailed descriptions of irrelevant parts or related known technologies that may unnecessarily obscure the spirit of the invention have been omitted, and reference numerals have been added to components in each figure. In this case, the same or similar reference numerals are assigned to the same or similar elements throughout the specification.

[0052] Furthermore, the terms or words used in this specification and claims should not be construed as having a general meaning or a dictionary-based meaning, but should be interpreted as meanings and concepts that are within the scope of the invention, based on the principle that the inventor can appropriately define the concepts of the terms in order to best describe and explain his or her invention.

[0053] Implementation Method 1

[0054] Figure 1 This is a schematic perspective view of a secondary battery 10 according to Embodiment 1 of the present invention, and Figure 2 This is a schematic exploded perspective view of a secondary battery 10 according to Embodiment 1 of the present invention.

[0055] The secondary battery 10 according to Embodiment 1 of the present invention may include an electrode assembly 100, an outer membrane 200, and a cover 300. Each configuration of the secondary battery 10 will be described in more detail below. For reference, the content of Embodiment 1 may be equally applied to the embodiments described later, provided there is no conflict.

[0056] 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 disposed between the positive and negative electrodes to physically separate them. The electrode assembly 100 may be configured in a stacked form, or in a wound form, in which the positive and negative electrodes and the separator are wound together.

[0057] The electrode assembly 100 may include electrode contacts 110 connected to the electrodes. The electrode contacts 110 may be provided separately or may be part of a current collector constituting the electrodes. For reference, in the case where the electrode assembly 100 is an all-solid-state battery, a solid electrolyte may be provided instead of a separator.

[0058] Reference Figure 2 According to embodiment 1 of the present invention, the secondary battery 10 may include an outer membrane 200. The outer membrane 200 of the secondary battery 10 may be configured to surround a portion of the electrode assembly 100. Specifically, the outer membrane 200 may be configured to surround the cover 300 and the electrode assembly 100, which will be described later. More specifically, the outer membrane 200 may be coupled to the cover 300 to define an internal space, and the electrode assembly 100 may be accommodated within the internal space.

[0059] To surround the electrode assembly 100, the outer membrane 200 can be made of a shape-deformable material. For example, the outer membrane 200 can be flexible.

[0060] Additionally, the outer membrane 200 can be made of a non-elastic material. In related technologies, a bag membrane is molded to define a space in which the electrode assembly is housed. However, since the outer membrane 200 does not need to be molded to deform its shape, it can be made of a non-elastic material. That is, the outer membrane 200 may not be elastic.

[0061] The outer membrane 200 of the secondary battery 10 may have a shape in which a sheet or membrane is wound along the side surface of the electrode assembly 100. That is, the outer membrane 200 may be configured to surround a side portion of the electrode assembly 100. Here, one end and the other end of the outer membrane 200 may be configured to be in contact with each other and surround the electrode assembly 100. Regarding the form in which one end and the other end of the outer membrane 200 are in contact with each other, one surface of one end may be attached to the other surface of the other end, such that the one surface and the other surface are in contact with each other (see [link to relevant documentation]). Figure 2 Furthermore, one surface of one end can be coupled to a surface of the other end, such that the two surfaces are in contact with each other. This is merely an example, and the form in which one end of the outer membrane 200 is coupled to define a space for accommodating the electrode assembly 100 can be varied.

[0062] Regarding the method of joining one end and the other end of the outer membrane 200 together, the one end and the other end of the outer membrane 200 can be joined together by sealing by heating or by sealing by heating and pressure. That is, the outer membrane 200 may include a material that has sealing properties when heated. Specifically, the outer membrane 200 may include a material that is heat-melted and has adhesive properties.

[0063] For example, the outer membrane 200 may include a sealant layer, a barrier layer, and an insulating layer.

[0064] The sealant layer may include at least one or more materials selected from the group consisting of: polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylate polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aromatic polyamide, nylon, polyester, poly(p-benzodioxazole), polyarylate, polytetrafluoroethylene, and glass fiber. Polyolefin-based resins such as polypropylene (PP) or polyethylene (PE) can be primarily used. In particular, polypropylene (PP) can possess 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 include one or more materials selected from the group consisting of iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), aluminum (Al), stainless steel (STS), and their alloys.

[0065] The insulating layer may include at least one or more materials selected from the group consisting of: polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylate polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aromatic polyamide, nylon, polyester, poly(p-benzodioxazole), polyarylate, polytetrafluoroethylene, and glass fiber.

[0066] The outer membrane 200 may be configured to surround a portion of the electrode assembly 100, and the cover 300 may be configured to surround the remainder of the electrode assembly 100. Specifically, when the outer membrane 200 is configured to surround the electrode assembly 100 along its side surface, an external opening may be defined at each of the two ends of the electrode assembly 100. The cover 300 of the secondary battery 10 may be attached to the outer membrane 200 in a manner that covers the external openings at each of the two ends of the electrode assembly 100, and the electrode assembly 100 may be accommodated within the internal space defined by the outer membrane 200 and the cover 300.

[0067] As an example of a method for joining the cover 300 to the outer membrane 200, the cover 300 and the outer membrane 200 may be joined together by welding. Specifically, the connecting portion 310 may include a metallic material, and the outer membrane 200 may include a metal layer at the portion facing the connecting portion 310, which can be joined to the connecting portion 310 by welding.

[0068] As another example of a method for attaching the cover 300 to the outer membrane 200, the cover 300 and the outer membrane 200 can be joined together by a seal. Specifically, the connecting portion 310 may include a resin material that has adhesive properties upon heating, and the outer membrane 200 may include a resin layer on the portion facing the connecting portion 310, which can be joined to the connecting portion 310 by heating and pressure. Here, the resin layer may include a material that has sealing properties upon heating as described above.

[0069] In the pouch cell according to the related art, the cup-shaped component housing the electrode assembly 100 can be molded from a sheet or film. During the molding process of the cup-shaped component, the plastic depth may be limited depending on the material properties of the sheet or film, and the capacity of housing the electrode assembly 100 may also be limited. Furthermore, when molding the sheet or film, the thickness is thinnest at the corners, which often leads to defects such as cracks. Additionally, the pouch cell according to the related art may require a gas collection component to collect gas during the degassing process to remove gas accumulated inside the pouch, and most of the gas collection component can be removed and discarded after the degassing process.

[0070] On the other hand, in the secondary battery 10 according to Embodiment 1 of the present invention, the outer membrane 200 can be used to match the volume of the electrode assembly 100, and therefore, there is no limitation on the capacity of the electrode assembly 10. Furthermore, since it is not necessary to mold the cup-shaped component, defects such as cracks in the outer membrane 200 can be prevented, and the material and thickness of the outer membrane 200 can be selected relatively freely. Additionally, since the electrolyte injection and degassing processes are performed through the cap 300, the economic efficiency of the process can be improved because no discarded outer membrane 200 is produced.

[0071] Although not described in detail in this invention, the cover 300 may also include an electrolyte injection port for injecting electrolyte or a gas discharge port for discharging gas during degassing.

[0072] Figure 3 It is along the embodiment 1 of the present invention. Figure 2 A schematic cross-sectional view of the secondary battery 10 taken by line A-A', and Figure 4 It's a diagram. Figure 3 A schematic cross-sectional view of a modified example of the cover 300.

[0073] Reference Figure 3 According to Embodiment 1 of the present invention, the cover 300 of the secondary battery 10 may include a connecting portion 310 and a terminal portion 320.

[0074] The connecting portion 310 of the cover 300 can be connected to the outer membrane 200. Additionally, the terminal portion 320 of the cover 300 can be connected to the connecting portion 310 and can be exposed on both the outer and inner sides of the connecting portion 310. Here, the inner side of the connecting portion 310 can refer to a portion of the internal space defined by the cover 300 and the outer membrane 200, and the outer side of the connecting portion 310 can refer to the external space of the cover 300 and the outer membrane 200. The portion of the terminal portion 320 exposed on the inner side of the connecting portion 310 can be electrically connected to the electrode assembly 100. Here, the electrical connection can include both a direct connection between the terminal portion 320 and the electrode assembly 100 and an indirect connection via another conductive member.

[0075] As an example of a method for joining the connecting portion 310 to the terminal portion 320, the joining can be achieved through sealing. The terminal portion 320 may include a metallic material, and the connecting portion 310 may include a resin material that has adhesive properties when heated. Therefore, the resin material of the adhesive connecting portion 310 can be melted by heating and joined to the terminal portion 320 by pressure.

[0076] As an example of a configuration that improves the structural stability of the cover 300, at least a portion of the terminal portion 320 of the cover 300 according to Embodiment 1 of the present invention can be embedded in the connecting portion 310. In this regard, the terminal portion 320 of the cover 300 may include a first member 321 and a second member 322.

[0077] A portion of the first member 321 of the terminal portion 320 may be exposed on the outside of the connection portion 310. Therefore, the terminal portion 320 electrically connected to the electrode assembly 100 can be electrically contacted with the outside through the first member 321 exposed on the outside of the connection portion 310. That is, the secondary battery 10 can provide electrical energy to the outside through the first member 321.

[0078] 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 configured such that one end toward the electrode assembly 100 is exposed to the inside of the connection portion 310. Here, the inside of the connection portion 310 may refer to a portion of the internal space defined by the outer membrane 200 and the cover 300.

[0079] Reference Figure 3 The terminal portion 320 may have multiple second members 322. Additionally, at least one second member 322 may be configured such that one end of the member facing the electrode assembly 100 is exposed inside the connection portion 310. Specifically, among the multiple second members 322 extending from the first member 321 toward the electrode assembly 100, some of the second members 322 may be embedded in the connection portion 310, and some of the second members 322 may be exposed inside the connection portion 310. Based on Figure 3 The second component 322 shown on the left can be embedded in the connecting portion 310, and the second component 322 shown on the right can be exposed inside the connecting portion 310.

[0080] One end of the second member 322 extending toward the electrode assembly 100 and into the connection portion 310 may be electrically connected to the electrode assembly 100. Here, the electrical connection may include both a direct connection between the second member 322 and the electrode assembly 100 and an indirect connection via another conductive member.

[0081] When the second component 322 and the electrode assembly 100 are directly connected to each other, the electrode contacts 110 of the electrode assembly 100 can be connected to the second component 322. Alternatively, when the second component 322 and the electrode assembly 100 are indirectly connected to each other, the secondary battery 10 can include a busbar 400, which serves as an example of a conductive component used as a medium.

[0082] Busbar 400 may be disposed between terminal portion 320 and electrode assembly 100 to connect one end of second member 322 exposed inside connection portion 310 to electrode assembly 100. Busbar 400 may be made of metal to be conductive. In addition, busbar 400 may be configured in various shapes depending on the length of second member 322, etc. Figure 3 This is a view illustrating the situation according to Embodiment 1 of the present invention, wherein the busbar 400 has an approximately plate-like or strip-like shape.

[0083] According to a modified example of Embodiment 1 of the present invention, the second member 322 may be configured such that one end of the member facing the electrode assembly 100 is exposed to the inside of the connection portion 310. Specifically, all of the plurality of second members 322 extending from the first member 321 toward the electrode assembly 100 may be exposed to the inside of the connection portion 310.

[0084] As described above, when the second component 322 and the electrode assembly 100 are directly connected to each other, the electrode contacts 110 of the electrode assembly 100 can be connected to the second component 322. Alternatively, when the second component 322 and the electrode assembly 100 are indirectly connected to each other, the secondary battery 10 can include a plurality of busbars 400, which serve as examples of conductive components used as a medium.

[0085] Reference Figure 4 According to the modified example, each of the plurality of busbars 400 of the secondary battery 10 can be connected to the second member 322 inside the connection portion 310. In this case, the electrode assembly 100 can be electrically connected to the second member 322 at multiple locations. Therefore, when the secondary battery 10 includes a plurality of electrode assemblies 100, the plurality of electrode assemblies 100 can be electrically connected to the busbars 400 disposed at proximal locations. Therefore, the battery capacity of the secondary battery 10 can be effectively increased.

[0086] According to Embodiment 1 of the present invention, the cover 300 can be configured such that one surface of the terminal portion 320 protrudes 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 can be configured to protrude outward from the connecting portion 310 beyond one surface of the connecting portion 310. Based on Figure 3 or Figure 4 Each of a surface of the first member 321 and a surface of the connecting portion 310 can be referred to as the top surface. In this case, it is easy to allow an object that wants to obtain electrical energy to contact the protruding first member 321.

[0087] As another example relating to the arrangement of the first member 321, one surface of the first member 321 may be disposed on the same surface as one surface of the connecting portion 310. In this case, since the first member 321 does not protrude to the outside of the connecting portion 310, multiple secondary batteries 10 can be easily arranged.

[0088] In the cover 300 of the secondary battery 10 according to Embodiment 1 of the present invention, the connecting portion 310 and the terminal portion 320, at least a portion of which is embedded in the connecting portion 310, can cover the electrode assembly 100. Depending on the material of the connecting portion 310, moisture on the outside of the connecting portion 310 may penetrate into the connecting portion 310. Moisture penetration may lead to defects in the secondary battery 10. In the cover 300 of the secondary battery 10 according to Embodiment 1 of the present invention, the terminal portion 320, made of metal, together with the connecting portion 310, can cover the electrode assembly 100, and therefore, the area through which moisture penetrates in the connecting portion 310 can be reduced. In addition, since at least a portion of the terminal portion 320 is provided in a shape that is embedded in the connecting portion 310, the moisture penetration path provided between the terminal portion 320 and the connecting portion 310 may make it difficult for moisture to penetrate. Therefore, the secondary battery 10 according to Embodiment 1 of the present invention can reduce the amount of water that penetrates into the interior, thereby reducing limitations on the performance of the secondary battery.

[0089] Furthermore, according to Embodiment 1 of the present invention, the cover 300 of the secondary battery 10 can be provided in a state in which the second member 322 of the terminal portion 320 is embedded in the connecting portion 310. Therefore, since the connecting portion 310 restricts the movement of the terminal portion 320 to prevent the terminal portion 320 from separating, the structural stability of the secondary battery 10 can be improved.

[0090] Although not described in detail in Embodiment 1 of the present invention, the cover 300 may also include a gas venting member (not shown) for venting gas inside the secondary battery 10 or an exhaust member (not shown) for causing exhaust in a particular direction.

[0091] Implementation Method 2

[0092] Figure 5 The illustration shows a schematic cross-sectional view of the cover 300' and the busbar 400' of the secondary battery 10 according to Embodiment 2 of the present invention. Figure 6 It's a diagram. Figure 5 A schematic cross-sectional view of a modified example of the 300' cover.

[0093] In the following text, detailed descriptions of configurations identical to those of the secondary battery 10 according to Embodiment 1 of the present invention will be omitted, and the description will focus on the differences. The secondary battery 10 according to Embodiment 2 of the present invention may differ from the secondary battery 10 according to Embodiment 1 in terms of the shape of the terminal portion 320', the shape of the busbar 400', and the connection method of the configuration.

[0094] The secondary battery 10 according to Embodiment 2 of the present invention may include an electrode assembly 100, an outer membrane 200, and a cover 300'. The outer membrane 200 of the secondary battery 10 may be configured to surround a portion of the electrode assembly 100. Specifically, the outer membrane 200 may be configured to surround the cover 300' and the electrode assembly 100. More specifically, the outer membrane 200 may be coupled to the cover 300 to define an internal space, and the electrode assembly 100 may be accommodated within the internal space.

[0095] The cover 300' of the secondary battery 10 may include a connecting portion 310 and a terminal portion 320'. The connecting portion 310 of the cover 300' may be coupled to the outer membrane 200, and the terminal portion 320' of the cover 300 may be coupled to the connecting portion 310, exposing each of the outer and inner sides of the connecting portion 310. Here, the inner side of the connecting portion 310 may refer to a portion of the internal space defined by the cover 300' and the outer membrane 200, and the outer side of the connecting portion 310 may refer to the external space of the cover 300' and the outer membrane 200. The portion of the terminal portion 320' exposed on the inner side of the connecting portion 310 may be electrically connected to the electrode assembly 100.

[0096] As an example of a configuration for effective electrical connection with electrode assembly 100, the terminal portion 320' of cover 300' according to embodiment 2 of the present invention may further include a third member 323.

[0097] Reference Figure 5 The third member 323 of the terminal portion 320' can extend from the first member 321 toward the electrode assembly 100. Specifically, the third member 323 can be configured to pass through the connection portion 310 to expose the inside of the connection portion 310. The third member 323 can have a shape extending from the center of the surface of the first member 321 facing the electrode assembly 100 toward the electrode assembly 100. The busbar 400', which will be described later, can be configured in various shapes according to the shape of the third member 323, and structural stability can be improved by increasing the contact area between the third member 323 and the busbar 400'.

[0098] Since the third member 323 is electrically connected to the electrode assembly 100, all the second members 322 can be disposed within the connecting portion 310. Here, the second members 322 can extend from the side portion of the first member 321 toward the electrode assembly 100. The second members 322 can be disposed along the edge of the first member 321. Since all the second members 322 disposed along the edge of the first member 321 are disposed within the connecting portion 310, the structural stability of the cover 300' can be improved. In this case, a relatively impermeable path for moisture can be provided between the connecting portion 310 and the terminal portion 320 to effectively prevent moisture from penetrating into the interior of the secondary battery 10. This is merely an example, and the second members 322 can be disposed only on a pair of opposite edges of the four edges of the first member 321, which has an approximately rectangular cross-section.

[0099] As an example of a configuration for electrically connecting the third component 323 to the electrode assembly 100, the secondary battery 10 according to Embodiment 2 of the present invention may further include a busbar 400'. Specifically, the busbar 400' may be disposed between the terminal portion 320' and the electrode assembly 100 to connect the third component 323 exposed inside the connection portion 310 to the electrode assembly.

[0100] As an example of a configuration for effective connection with the third member 323, the busbar 400' according to Embodiment 2 of the present invention may include a first metal portion 410, a second metal portion 420, a third metal portion 430 and a fourth metal portion 440.

[0101] Reference Figure 5 The first metal portion 410 may contact the third member 323. For example, the first metal portion 410 may have a generally plate-like shape and may extend parallel to the direction in which the first member 321 extends. Additionally, the first metal portion 410 may be configured such that its surface facing the third member 323 contacts the third member 323. Here, the third member 323 may comprise a metallic material, and the third member 323 and the first metal portion 410 may be joined together by welding.

[0102] The second metal portion 420 may extend from the first metal portion 410 toward the electrode assembly 100. Here, the second metal portion 420 may extend in a direction substantially perpendicular to the direction in which the first metal portion 410 extends.

[0103] The third metal portion 430 may extend from the second metal portion 420 toward the outer membrane 200. Here, the third metal portion 430 may extend in a direction substantially perpendicular to the direction in which the second metal portion 420 extends. Specifically, the third metal portion 430 may extend in a direction away from the third member 323.

[0104] The fourth metal portion 440 can extend from the third metal portion 430 toward the electrode assembly 100. Additionally, one end of the fourth metal portion 440 can be connected to the electrode assembly 100. Specifically, one end of the fourth metal portion 440 can be connected to the electrode tab 110 of the electrode assembly 100.

[0105] The busbar 400', which includes a first metal part 410, a second metal part 420, a third metal part 430, and a fourth metal part 440, can be changed into various shapes depending on the number, arrangement, and shape of the electrode assembly 100.

[0106] Reference Figure 6 According to a modified example of Embodiment 2 of the present invention, the busbar 400' can be composed of a first metal portion 410 and a second metal portion 420. Here, one end of the second metal portion 420 can be connected to the electrode assembly 100. In this case, the busbar 400' can be disposed in the space defined inside the connecting portion 310 by the connecting portion 310. Therefore, when arranging the electrode assembly 100, space efficiency can be improved, and battery capacity can be increased.

[0107] Adhesive 500 can be used as a component for connecting the connecting portion 310 and the terminal portion 320'. That is, the connecting portion 310 and the terminal portion 320' can be joined together by applying adhesive 500 between the connecting portion 310 and the terminal portion 320'. Additionally, the connecting portion 310 and the outer membrane 200 can also be joined together by applying adhesive 500 between the connecting portion 310 and the outer membrane 200. Here, the type and application method of the adhesive 500 used for joining can be varied. Adhesive 500 can be made of a material with relatively high hydrophobicity.

[0108] Implementation Method 3

[0109] Figure 7 This is a schematic exploded perspective view of the battery pack 1 according to Embodiment 3 of the present invention.

[0110] According to embodiment 3 of the present invention, the battery pack 1 may include a plurality of secondary batteries 10. In addition, the battery pack 1 may include a package 20 therein for accommodating the plurality of secondary batteries 10.

[0111] The package 20 can have various shapes. For example, the package 20 may include a busbar electrically connected to a plurality of secondary batteries 10. Here, the package 20 may also include a busbar frame for securing the busbar.

[0112] The number of secondary batteries 10 housed inside the package 20 can vary depending on the battery pack 1.

[0113] Although the invention has been shown and described in conjunction with exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations may be made without departing from the spirit and scope of the invention as defined by the appended claims.

[0114] List of reference numerals

[0115] 1: Battery pack

[0116] 10: Secondary batteries

[0117] 20: Package

[0118] 100: Electrode assembly

[0119] 200: External membrane

[0120] 300, 300': Cover

[0121] 310: Connection part

[0122] 320, 320': Terminal section

[0123] 321: First component

[0124] 322: Second component

[0125] 323: Third component

[0126] 330: Coverage area

[0127] 400, 400': Busbar

[0128] 410: First metal part

[0129] 420: Second metal part

[0130] 430: Third metal part

[0131] 440: Fourth metal part

[0132] 500: Adhesive

Claims

1. A secondary battery, comprising: Electrode assembly; An outer membrane, the outer membrane being configured to surround a portion of the electrode assembly; as well as A cover, configured to cover the remainder of the electrode assembly. The cover includes: The connecting portion is coupled to the outer membrane; and A terminal portion, which is coupled to the connection portion, is exposed on both the inner and outer sides of the connection portion, and is electrically connected to the electrode assembly at the portion of the terminal portion exposed on the inner side of the connection portion. At least a portion of the terminal portion is embedded in the connection portion.

2. The secondary battery according to claim 1, wherein, The terminal portion includes: A first component, the first component being exposed on the outside of the connecting portion; and A second component extends from the first component toward the electrode assembly.

3. The secondary battery according to claim 2, wherein, The second component is configured such that one end of the electrode assembly is exposed to the inside of the connection portion.

4. The secondary battery of claim 3 further includes a busbar disposed between the terminal portion and the electrode assembly to connect one end of the second member exposed inside the connection portion to the electrode assembly.

5. The secondary battery according to claim 2, wherein, The second component extends from the side portion of the first component toward the electrode assembly and is embedded in the connection portion to be covered by the connection portion. The terminal portion further includes a third member extending from the first member toward the electrode assembly and configured to pass through the connection portion to expose the inside of the connection portion.

6. The secondary battery of claim 5 further includes a busbar disposed between the terminal portion and the electrode assembly to connect the third member exposed inside the connection portion to the electrode assembly.

7. The secondary battery according to claim 6, wherein, The busbar includes: A first metal portion, the first metal portion being in contact with the third component; and A second metal portion extends from the first metal portion toward the electrode assembly, and one end of the second metal portion is connected to the electrode assembly.

8. The secondary battery according to claim 6, wherein, The busbar includes: A first metal portion, which is in contact with the third component; A second metal portion extends from the first metal portion toward the electrode assembly; A third metal portion, the third metal portion extending from the second metal portion toward the outer membrane; and A fourth metal portion extends from the third metal portion toward the electrode assembly, and one end of the fourth metal portion is connected to the electrode assembly.

9. The secondary battery according to claim 6, wherein, The third component comprises a metallic material, and The third component and the busbar are connected to each other by welding.

10. The secondary battery according to claim 1, wherein, The terminal portion is configured such that one surface of the terminal portion protrudes from one surface of the connection portion in a direction away from the electrode assembly.

11. The secondary battery according to claim 1, wherein, In the cover, one surface of the connecting portion is disposed on the same surface as one surface of the terminal portion.

12. The secondary battery according to claim 1, wherein, The terminal portion includes a metallic material. The connecting portion includes a resin material with adhesive properties that can be heated, and The terminal portion and the connecting portion are connected to each other by heating and pressure.

13. The secondary battery according to claim 1, wherein, The connecting portion and the terminal portion are joined together by an adhesive applied between the connecting portion and the terminal portion.

14. The secondary battery according to claim 1, wherein, The connecting portion includes a metallic material, and The outer membrane includes a metal layer that is welded to the connection portion.

15. The secondary battery according to claim 1, wherein, The outer membrane comprises a sealant layer with adhesive properties that can be bonded by heating and a barrier layer containing metal. The barrier layer comprises one or more materials selected from the group consisting of iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), aluminum (Al), stainless steel (STS), and their alloys.

16. The secondary battery according to claim 1, wherein, The connecting portion includes a resin material with adhesive properties that can be heated, and The outer membrane includes a resin layer that is bonded to the connection portion by heating and pressure.

17. The secondary battery according to claim 1, wherein, The outer membrane and the connecting portion are joined together by an adhesive applied between the outer membrane and the connecting portion.

18. The secondary battery according to claim 1, wherein, The outer membrane includes a flexible membrane.

19. The secondary battery according to claim 1, wherein, The outer membrane includes a flexible membrane that is not elastic.

20. A method for preparing a secondary battery, the method comprising: Provides electrode assemblies including positive and negative electrodes; This causes the outer membrane to surround a portion of the electrode assembly; as well as This allows the cover to cover the rest of the electrode assembly. The cover includes: The connecting portion is coupled to the outer membrane; and A terminal portion, which is coupled to the connection portion, is exposed on both the inner and outer sides of the connection portion, and is electrically connected to the electrode assembly at a portion of the inner side of the connection portion. At least a portion of the terminal portion is embedded in the connection portion.

21. A battery pack, comprising: According to claim 1, the secondary battery is provided in multiple configurations; as well as A package, the package being configured to accommodate a plurality of the secondary batteries.

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