Secondary battery with electrolyte injection port

Abstract

Secondary battery, including: a housing structured to accommodate an electrode assembly; a cap plate that is placed on the housing to seal an opening in the housing; an electrolyte injection port located in the cap plate to inject an electrolyte into an interior of the housing; a sealing element configured to seal the electrolyte injection port, the sealing element includes: an inner cap attached to an inner surface of the electrolyte injection port; and an outer cap that is inserted into and attached to the inner cap and is configured to elastically compress the inner cap towards the inner surface.

Description

TECHNICAL FIELD

[0001] The disclosed technology relates to a secondary battery including an electrolyte injection port. BACKGROUND

[0002] Secondary batteries are energy storage devices that can be electrically charged or discharged. They are widely used in various applications that require electricity as a power source. For example, secondary batteries are used as energy storage devices in various systems ranging from small electronic devices, such as mobile phones, laptops, and tablets, to larger systems, such as vehicles and aircraft. Recently, their use as a power source for vehicles has been actively pursued. SUMMARY

[0003] The disclosed technology may be implemented in some embodiments to provide a secondary battery capable of improving a sealing structure of an electrolyte injection port.

[0004] In one embodiment of the disclosed technology, in some embodiments, it may be implemented to provide a secondary battery with an improved sealing structure capable of improving safety by effectively responding to changes in internal pressure.

[0005] In one embodiment of the disclosed technology, in some embodiments, it may be implemented to provide a secondary battery capable of inducing a uniform injection of an electrolyte.

[0006] A secondary battery based on some embodiments of the disclosed technology can be widely applied in green technology fields, such as electric vehicles, battery charging stations, and solar and wind power generation using other batteries. Additionally, the secondary battery based on some embodiments of the disclosed technology can be used in environmentally friendly electric vehicles, hybrid vehicles, and other systems to prevent climate change by suppressing air pollution and greenhouse gas emissions.

[0007] A secondary battery based on some embodiments of the disclosed technology may include: a casing in which an electrode assembly is housed; a cap plate disposed on the casing to seal an opening of the casing; an electrolyte injection port disposed in the cap plate to inject an electrolyte into an interior of the casing; and a sealing member that seals the electrolyte injection port. The sealing member may include: an inner cap attached to an inner surface of the electrolyte injection port; and an outer cap inserted into and attached to the inner cap and configured to elastically compress the inner cap toward the inner surface.

[0008] In one embodiment, the outer cap may be coupled to the inner cap by means of screws and configured to gradually elastically compress the inner cap toward the inner surface as the outer cap moves inward through the screw coupling.

[0009] In one embodiment, the inner cap may include an insertion path configured to receive the inserted outer cap, and wherein a diameter of the insertion path may gradually decrease in an insertion direction of the outer cap.

[0010] In one embodiment, the inner cap may include an outer surface attached to the inner surface, and wherein a diameter of the outer surface may gradually decrease in an insertion direction of the outer cap.

[0011] In one embodiment, a diameter of the inner surface may gradually decrease in the insertion direction of the outer cap to match the outer surface. The inner cap may be supported in the electrolyte injection hole by aligning the outer surface of the electrolyte injection hole with the inner surface of the electrolyte injection hole.

[0012] In one embodiment, wherein the outer cap may include an insertion portion that is inserted into the inner cap, and wherein a diameter of the insertion portion may gradually decrease in an insertion direction of the outer cap.

[0013] In one embodiment, the inner cap may be formed such that an outer surface of the electrolyte injection hole has a predetermined diameter and extends both upward and downward, and a flange supported by a step surface formed in the electrolyte injection hole may be disposed at an upper end of the outer surface of the electrolyte injection hole.

[0014] In one embodiment, the inner cap may be configured such that a degree of elastic compression in a transverse direction between an upper region and a lower region varies depending on an insertion direction of the outer cap.

[0015] In one embodiment, at least a portion of the inner cap may be formed from an elastic material. The outer cap may comprise a material that is harder than the inner cap and may be welded and fixed to the cap plate.

[0016] In one embodiment, the cap plate may include a first cap plate disposed on a first side of the housing and a second cap plate disposed on a second side of the housing opposite the first side. The electrolyte injection port may include at least one of: a first electrolyte injection port enclosed in the first cap plate; or a second electrolyte injection port enclosed in the second cap plate.

[0017] In one embodiment of the disclosed technology, a secondary battery may include: a case in which an electrode assembly is housed; a cap plate disposed on the case to seal an opening of the case; an electrolyte injection port enclosed in the cap plate to inject an electrolyte into an interior of the case; and a sealing member that seals the electrolyte injection port.The sealing member may include: an inner cap including a first insertion path to provide an injection path for an electrolyte and a second insertion path to provide an exhaust path for internal gas during electrolyte injection, and an outer cap including: a first insertion portion inserted into and fixed to the first insertion path to close the first insertion path, and a second insertion portion inserted into and fixed to the second insertion path.

[0018] In some embodiments of the disclosed technology, the inner cap may include a protruding rib extending upward from a bottom surface of the inner cap by a predetermined height to form the first insertion path. The protruding rib may be configured such that an upper end of the protruding rib includes a predetermined gap and is positioned lower than an upper end of the inner cap, and may be configured to guide the electrolyte overflowing from the first insertion path through the gap into the second insertion path.

[0019] In one embodiment, the inner cap may include a vent hole communicating with the second insertion path. The second insertion portion may be spaced from the vent hole by a predetermined gap, and the gap may be configured to buffer internal pressure transmitted to the outer cap.

[0020] In one embodiment, the inner cap may have a flange placed and supported within a set-off groove provided in the cap plate, or at least a portion of the inner cap is integrated with the cap plate.

[0021] In one embodiment, the outer cap may include a first bevel arranged to correspond to a second bevel provided on the cap plate and welded and bonded between the cap plate and the outer cap.

[0022] A secondary battery based on some embodiments of the disclosed technology may provide a sealing member for sealing an electrolyte injection port. The sealing member based on some embodiments of the disclosed technology may include an outer cap and an inner cap, and the inner cap may be configured to be elastically compressed by the outer cap. Accordingly, the sealing member may establish a more effective sealing structure with the casing. Additionally, the sealing member may improve the safety of the secondary battery by responding to changes in the internal pressure of the casing.

[0023] A sealing member based on some embodiments of the disclosed technology may include an outer cap and an inner cap, and a first insertion path and a second insertion path may be formed in the inner cap. The first insertion path may function as a passage for injecting the electrolyte, and the second insertion path may function as a passage for discharging gas within the housing. In this way, the first and second injection paths may enable more uniform injection of the electrolyte.

[0024] The technical effects achieved by the embodiments of the disclosed technology are not limited to those mentioned above. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Certain aspects, features and advantages of the disclosed technology are illustrated by the following detailed description with reference to the accompanying drawings. Fig. 1A is a schematic external perspective view of a secondary battery according to an embodiment. Fig. 1B is a schematic exploded perspective view of the Fig. 1A illustrated secondary battery. Fig. Figure 1C is a schematic internal cross-sectional view of the Fig. 1A illustrated secondary battery. Fig. 2A is a schematic exploded perspective view of a sealing member according to one embodiment. Fig. Figure 2B is a schematic cross-sectional view of the Fig. 2A illustrated sealing member. Fig. 2C is a schematic assembly flow diagram of the Fig. 2A illustrated sealing member. Fig. 3A is a schematic cross-sectional view of a sealing member according to another embodiment. Fig. 3B is a schematic assembly state diagram of the Fig. 3A illustrated sealing member. Fig. 4A is a schematic cross-sectional view of a sealing member according to another embodiment. Fig. 4B is a schematic assembly flow diagram of the Fig. 4A illustrated sealing member. Fig. 5A is a schematic cross-sectional view of a sealing member according to another embodiment. Fig. 5B is a schematic assembly flow diagram of the Fig. 5A illustrated sealing member. DETAILED DESCRIPTION

[0026] Various embodiments of the disclosed technology will now be described with reference to the accompanying drawings. These descriptions are merely examples, and the presently disclosed technology is not limited to the specific embodiments described in this patent document.

[0027] Secondary batteries can be classified into lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and lithium-ion batteries depending on the electrode material. Each type of secondary battery can be appropriately selected depending on the design capacity, usage environment, and the like. Lithium-ion batteries can implement relatively high voltage and capacity compared to other types of secondary batteries. Accordingly, lithium-ion batteries are widely used in fields requiring high-density energy storage devices, such as vehicle battery packs.

[0028] Secondary batteries, such as lithium-ion batteries, mainly include a positive electrode material, a negative electrode material, a separator, and an electrolyte. The positive electrode material and the negative electrode material may be arranged with an insulating separator between them, and charging or discharging may be performed by the movement of ions through the electrolyte.

[0029] In some types of secondary batteries, the electrolyte may be injected into a casing containing the positive electrode material, the negative electrode material, the separator, and the like. In this case, an injection port for injecting the electrolyte may be formed in the casing or in a cap plate, and the injection path may be suitably sealed after the electrolyte is injected. Generally, the injection path is sealed by pressing in a spherical sealing member or the like.

[0030] The above explanation is provided to assist in understanding the technical background of the disclosed technology and should not be interpreted as reducing, limiting, or restricting the technical idea of ​​the disclosed technology. In addition, the contents described or suggested in the above explanation do not necessarily relate to the conventional technology, and some descriptions may include content that does not conform to the conventional technology.

[0031] A secondary battery or battery cell described in this specification may include a rechargeable battery. For example, the secondary battery may include a lead-acid battery, a nickel-cadmium battery, a nickel-hydrogen battery, and a lithium-ion battery. This description primarily assumes that the secondary battery is a lithium-ion battery. In general, a lithium-ion battery may have advantages of lightweight, high energy density, low self-discharge rate, and the like. However, it should be understood that the technical concepts described in this specification may be applied to other suitable types of batteries in addition to lithium-ion batteries.

[0032] The secondary battery described in this specification may include a single physical unit or a cluster unit in which multiple basic units are combined. For example, the secondary battery may include a battery cell, a battery module, and a battery pack, according to the classification criteria generally used in the current automotive field. In this specification, the secondary battery is primarily assumed to be a battery cell, which is a single unit. Generally, the battery cell is a basic component unit of a battery pack, including a positive electrode material, a negative electrode material, a separator, and an electrolyte.However, it should be understood that the technical concepts described in this patent specification may be applied to other suitable types of cluster units, such as a battery module or a battery pack, as needed.

[0033] The secondary battery described in this specification may include various packaging types. For example, the secondary battery may be packaged in a cylindrical, square, pocket-like, or coin-like shape, according to the classification criteria commonly used in the current relevant field. In this specification, it is mainly assumed that the secondary battery is packaged in a square shape. A square package, referred to as square batteries, may generally have advantages in terms of durability, safety, and ease of installation. However, it should be understood that the technical concepts described in this specification may be applied to other suitable packaging types, such as cylindrical, pocket-like, and coin-like types, as needed.

[0034] The secondary battery described in this patent can be used in various devices that require electrical energy. For example, the secondary battery can be used in the field of vehicles that use electrical energy as a primary or auxiliary power source. As another example, the secondary battery can be used in the field of aircraft, such as personal aircraft, unmanned aerial vehicles, and drones; electronic devices, such as mobile phones, laptop computers, and tablets; and power tools, such as electric drills, electric grinders, and electric hammers. However, it should be understood that the secondary battery described in the present patent can be widely used in various devices that are also powered by electrical energy.

[0035] Fig. 1A is a schematic external perspective view of a secondary battery based on an embodiment. Fig. 1B is a schematic exploded perspective view of the Fig. 1A illustrated secondary battery. Fig. Figure 1C is a schematic internal cross-sectional view of the Fig. 1A. For example, Fig. 1C is a cross-sectional view along line 1c-1c' of Fig. 1A.

[0036] For ease of explanation, one embodiment exemplifies a single battery cell packaged in a square shape.

[0037] With reference to Fig. 1A to 1C, a secondary battery 100 based on one embodiment may include a housing 110.

[0038] Housing 110 may provide an interior space in which an electrode assembly 120 or the like may be housed. In one embodiment, housing 110 is illustrated as having an approximately rectangular cuboid shape.

[0039] The housing 110 may include an opening 111 connected to the interior space. In one embodiment, the opening 111 is exemplified as being provided in an upper end of the housing 110. However, a position of the opening 111 may be changed as needed and is not necessarily limited to what is exemplified. The opening 111 may function as a passage for inserting an electrode assembly 120 or the like. Additionally, the opening 111 may function as a connection space for electrically connecting the electrode assembly 120 and an electrode terminal. The opening 111 may be closed by a cap plate 130.

[0040] A material of the housing 110 can be appropriately selected taking into account thermal and electrical conductivity, stiffness corresponding to swelling of the electrode assembly 120, processability, manufacturing cost, or the like. For example, the housing 110 can be formed from a metal material including aluminum and an aluminum alloy.

[0041] In some implementations, the secondary battery 100 may include the electrode assembly 120.

[0042] The electrode assembly 120 may be disposed within an interior space of the housing 110. If necessary, the electrode assembly 120 may be housed in an insulating bag 124 and disposed within the housing 110.

[0043] The electrode assembly 120 may include a positive electrode material 121. The positive electrode material 121 may include a positive electrode current collector and a positive electrode active material. In some embodiments, the positive electrode current collector may include aluminum and an aluminum alloy, and the cathode active material may include lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, and lithium iron phosphate. The positive electrode active material may be coated on a surface of the positive electrode current collector. A portion of the positive electrode current collector on which the positive electrode active material is not coated may function as a positive electrode tab 121a. In some embodiments, a plurality of positive electrode tabs 121a may be provided, and some or all of a plurality of positive electrode tabs 121a may be mutually bonded to each other.

[0044] The electrode assembly 120 may include a negative electrode material 122. The negative electrode material 122 may include a negative electrode current collector and a negative electrode active material. In some embodiments, the negative electrode current collector may include copper, a copper alloy, nickel, and a nickel alloy, and the negative electrode active material may include carbon and silicon. The negative electrode active material may be coated on a surface of the negative electrode current collector. A portion of the negative electrode current collector on which the negative electrode active material is not coated may function as a negative electrode tab 122a. In some embodiments, a plurality of negative electrode tabs 122a may be provided, and some or all of the plurality of negative electrode tabs 122a may be bonded together.

[0045] The electrode assembly 120 may include a separator 123. The separator 123 may be disposed between a positive electrode material 121 and a negative electrode material 122. The separator 123 may function to restrict physical contact between the positive electrode material 121 and the negative electrode material 122 and may function to provide a passageway for ion movement. In some embodiments, the separator 123 may be formed from a polymeric material, including polyethylene, polypropylene, or the like. Additionally, the separator 123 may include a dry and wet separator. In some embodiments, the separator 123 may include a coating layer including a ceramic coating layer.

[0046] The electrode assembly 120 may be formed by arranging the components, such as by winding, stacking, or the like. For example, the electrode assembly 120 may be formed in a structure in which the positive electrode material 121, the negative electrode material 122, and the separator 123 are wound around a longitudinal or transverse axis. Alternatively, the electrode assembly 120 may be formed in a structure in which the wound structure is compressed in a direction approximately perpendicular to a winding axis. The wound structure may be referred to in the related art as a 'jelly roll'.

[0047] As another example, the electrode assembly 120 may be formed in a structure in which the positive electrode material 121, the negative electrode material 122, and the separator 123 are sequentially stacked in an up-down direction (e.g., in a thickness direction or a height direction of the electrode assembly). In some cases, the separator 123 may be formed in the stacked structure to have a structure in which a plurality of unit separators 123 are continuously folded in a longitudinal direction and stacked according to the stacking of the positive electrode material 121 and the negative electrode material 122. The stacked structure may be referred to in the related art as 'stacking and folding,' 'Z-folding,' or the like. However, in one embodiment, arrangements of each component of the electrode assembly 120 are not particularly limited.The electrode assembly 120 may have various arrangements other than those exemplified above.

[0048] In some embodiments, the electrode assembly 120 may be formed by combining a plurality of base units. For example, the electrode assembly 120 may include a base unit wound in a jelly-roll manner, and two or more of the base units may be combined to form the electrode assembly 120. In one embodiment, the electrode assembly 120 is formed by combining two jelly-roll units. As another example, the electrode assembly 120 may include a base unit wound in a stack-and-fold manner, and two or more of the base units may be combined to form the electrode assembly 120.

[0049] The electrode assembly 120 may be housed in an interior space of the housing 110 along with an electrolyte. In some embodiments, the electrolyte may be formed from an organic solvent including a lithium salt. For example, the lithium salt may include lithium hexafluorophosphate (LiPF6) and lithium tetrafluoroborate (LiBF4) in liquid or gel form, and the organic solvent may include a cyclic carbonate such as ethylene carbonate (EC) and propylene carbonate (PC), and a linear carbonate such as diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC).

[0050] In some other embodiments, the electrolyte may be omitted or replaced. For example, if an inorganic solid electrolyte is used, a liquid or gel electrolyte may be omitted.

[0051] In some implementations, the secondary battery 100 may include the cap plate 130.

[0052] The cap plate 130 may be configured to close the opening 111. In one embodiment, the cap plate 130 is exemplified as a square plate shape corresponding to the opening 111. The cap plate 130 may be coupled to the housing 110 to seal the interior of the housing 110, in which the electrode assembly 120 is disposed. In some embodiments, the cap plate 130 may be welded to the housing 110 by ultrasonic welding, laser welding, or the like.

[0053] A positive electrode terminal 131 and a negative electrode terminal 132 may be disposed on the cap plate 130. The positive electrode terminal 131 may be electrically connected to the positive electrode tab 121a of the electrode assembly 120, and the negative electrode terminal 132 may be electrically connected to the negative electrode tab 122a of the electrode assembly 120.

[0054] The cap plate 130 may include a vent 133. In one embodiment, the vent 133 is disposed between the positive electrode terminal 131 and the negative electrode terminal 132. However, a position of the vent 133 may be variously changed as needed and is not necessarily limited to what is exemplified. In some other embodiments, the vent 133 may be disposed within or added to the housing 110. The vent 133 may be configured to open in response to the internal pressure of the housing 110. The vent 133 may function to vent the internal pressure to the outside of the housing 110 to contribute to stabilizing the internal elements of the housing 110. In one embodiment, the vent 133 may include a recess 133a having a predetermined shape.The recess 133a may be formed to partially open the interior of the housing 110 by inducing a rupture according to the internal pressure.

[0055] The cap plate 130 may include an electrolyte injection port 134. The electrolyte injection port 134 may be used to inject an electrolyte into the interior of the housing 110. In one embodiment, the electrolyte injection port 134 is located adjacent to the vent 133 in a central region of the cap plate 130. However, a position of the electrolyte injection port 134 may be varied in various ways and is not necessarily limited to what is exemplified.

[0056] The electrolyte injection port 134 may be suitably sealed after an electrolyte injection process, a chemical reaction process, or the like. In one embodiment, the electrolyte injection port 134 may be sealed by a sealing member 400 described below.

[0057] A structure of the electrode assembly 120 illustrated in the disclosed technology is exemplary. In the disclosed technology, the electrode assembly 120 is illustrated including the positive electrode tab 121a and the negative electrode tab 122a arranged in parallel from one side of the electrode assembly 120, but the positions and / or numbers of the positive electrode tab 121a and the negative electrode tab 122a are exemplary. For example, in a non-illustrated embodiment, the positive electrode tab 121a and the negative electrode tab 122a may be arranged so that the electrode assembly 120 (e.g., the positive electrode material 121, the negative electrode material 122, and the separator 123) is sandwiched therebetween. At least a portion of the positive electrode tab 121a and the negative electrode tab 122a may be sandwiched between the housing 110 and the housing 110, respectively.the electrode assembly 120.

[0058] In the disclosed technology, a secondary battery 100 is illustrated including the casing 110 including an opening 111 and the cap plate 130 disposed on one side (or a first side) of the casing 110, but this is exemplary. In an unillustrated embodiment, a secondary battery 100 may be provided including a plurality of cap plates 130 disposed on both sides of the casing 110. For example, the secondary battery 100 may include a first cap plate disposed on one side of the casing 110 and a second cap plate disposed on the other side (or a second side) of the casing 110. The electrolyte injection port 134 may be provided on at least one of the plurality of cap plates 130.For example, the electrolyte injection port 134 may include a first electrolyte injection port enclosed in the first cap plate and / or a second electrolyte injection port enclosed in the second cap plate. The secondary battery 100 may include at least one electrolyte injection port 134 provided in the first cap plate and / or the second cap plate, and at least one sealing member (e.g., a sealing member 200 of FIG. Fig. 2A), which seals the at least one electrolyte injection opening.

[0059] Fig. 2A is a schematic exploded perspective view of a sealing member based on one embodiment. Fig. Figure 2B is a schematic cross-sectional view of the Fig. 2A illustrated sealing member.

[0060] With reference to Fig. 2A and Fig. 2B, a sealing member 200 may include an outer cap 210 based on one embodiment.

[0061] The outer cap 210 may form an upper structure of the sealing member 200. In one embodiment, the outer cap 210 may be formed from a metal or a similar hard material. This contrasts with an inner cap 220 described below, which is formed from a resilient material.

[0062] The outer cap 210 may include an upper portion 211. The upper portion 211 may have a first diameter D1 in a plane. A tool attachment portion 212 may be formed in the center of the upper surface of the upper portion 211. The outer cap 210 may be joined to the inner cap 220 by rotating an assembly tool attached to the tool attachment portion 212. A first chamfer 213 for welding to the cap plate 130 may be formed in an upper periphery of the upper portion 211.

[0063] The outer cap 210 may include an insertion portion 214. The insertion portion 214 may be formed to extend downward from a center of a lower surface of the upper portion 211 by a predetermined length. The insertion portion 214 may have a second diameter D2 in a plane, and the second diameter D2 may be formed to be smaller than the first diameter D1 of the upper portion 211 by a predetermined degree. Additionally, a first spiral portion 215 may be formed on a lateral circumference of the insertion portion 214. The first spiral portion 215 may be coupled by screws to a second spiral portion 222 of an insertion path 221 described below.

[0064] In some implementations, the sealing member 200 may include the inner cap 220 based on one embodiment.

[0065] The inner cap 220 may be attached to a lower portion of the outer cap 210. In one embodiment, the inner cap 220 may be formed of a material capable of undergoing elastic deformation to a predetermined degree. Alternatively, part or all of the inner cap 220 may be formed of an elastic material. The inner cap 220 may be in close contact with an inner surface 232a of the electrolyte injection port 134 according to the attachment of the outer cap 210 and may be elastically deformed.

[0066] The inner cap 220 may include the insertion path 221. The insertion path 221 may be configured to extend upward and downward and penetrate the center of the inner cap 220. The insertion portion 214 of the outer cap 210 may be inserted into and secured to the insertion path 221.

[0067] In one embodiment, the insertion portion 214 of the outer cap 210 may be inserted into and secured to the inner cap 220 while elastically deforming the inner cap 220. Specifically, the insertion portion 214 may be configured to elastically compress the inner cap 220 in a transverse direction while moving downward along the insertion path 221.

[0068] In one embodiment, the insertion path 221 is formed such that a diameter thereof decreases from an upper end to a lower end, thus implementing the insertion and compression as described above. Specifically, an upper end of the insertion path 221 may have a second diameter D2 corresponding to the insertion portion 214, and a lower end of the insertion path 221 may have a third diameter D3 smaller than a diameter of the upper end by a predetermined degree. In addition, the insertion path 221 may be formed such that a diameter thereof gradually decreases from the upper end to the lower end. A shape of the insertion path 221 may allow the inner cap 220 to be elastically compressed in a transverse direction while the insertion portion 214 enters the insertion path 221.

[0069] In some implementations, the second spiral portion 222 may be formed on an inner surface of the inner cap 220 surrounding the insertion path 221. The second spiral portion 222 may have a pitch corresponding to the first spiral portion 215 of the outer cap 210 and may be connected to the first spiral portion 215 by screws. The outer cap 210 and the inner cap 220 may be mutually joined by screw coupling between the first and second spiral portions 215 and 222. The first and second spiral portions 215 and 222 may allow the inner cap 220 to be elastically compressed in a transverse direction as the insertion portion 214 gradually enters the insertion path 221.

[0070] In some implementations, the inner cap 220 may include an outer surface 223. An outer surface 223 of the inner cap 220 may be connected to an inner surface 232a of an electrolyte injection port 230 described below. In one embodiment, the outer surface 223 of the inner cap 220 may be formed as an inclined surface in which a width thereof becomes narrower as the peripheral surface 223 moves downward. Specifically, the outer surface 223 of the inner cap 220 may have a fourth diameter D4 in an upper portion thereof and may have a fifth diameter D5, which is smaller than the fourth diameter D4 by a predetermined amount, in a lower portion thereof.In one embodiment, the fourth diameter D4 of the upper portion may be formed to be smaller than the first diameter D1 of the upper portion 211 of the outer cap 210 by a predetermined amount, and the fifth diameter D5 of the lower portion may be formed to be larger than the second diameter D2 of the insertion portion 214 of the outer cap 210 by a predetermined amount. The outer surface 223 of the inner cap 220 may be formed to extend obliquely between the upper portion having the fourth diameter D4 and the lower portion having the fifth diameter D5.

[0071] The outer surface 223 of the inner cap 220, formed as an inclined surface as described above, can function as a support structure for arranging the inner cap 220 during an installation process of the inner cap 220. That is, the outer peripheral surface 223 formed as the inclined surface can be set on the inner peripheral surface 232a surrounding the electrolyte injection hole 134, so that the inner cap 220 can be supported within the electrolyte injection hole 134.

[0072] In some embodiments, the cap plate 130 may include an electrolyte injection port 230.

[0073] For reference, Fig. 2A and the like to facilitate the explanation of a Fig. 1A and the like is assigned a new reference number. The description of the electrolyte injection port 134 of Fig. 1A, Fig. 1B and Fig. 1C can access an electrolyte injection port 230 of Fig. 2A, Fig. 2B and Fig. 2C(a) and Fig. 2C(b) may be applied.

[0074] The electrolyte injection port 230 is formed by penetrating the cap plate 130 and can provide a passage for injecting the electrolyte into the interior of the housing 110.

[0075] In one embodiment, the electrolyte injection port 230 may include an upper region 231 and a lower region 232. The upper region 231 refers to a portion of the electrolyte injection port 230 located toward the outside of the housing 110, and the lower region 232 refers to a remaining portion of the electrolyte injection port 230 located toward the inside of the housing 110. The upper region 231 and the lower region 232 may be arranged in a thickness direction of the cap plate 130, thus forming a continuous electrolyte injection port 230 in the thickness direction.

[0076] The upper region 231 may be configured to accommodate the upper end 211 of the outer cap 210. The upper region 231 may have a first diameter D1 corresponding to the upper portion 211 of the outer cap 210 and a first height H1 corresponding to the upper portion 211. The upper portion 211 may be disposed in the upper region 231 and may be fixed to the cap plate 130 by welding or the like. A second chamfer 233 may be formed on an upper end of an inner surface 231a surrounding the upper region 231. The second chamfer 233 may be arranged to correspond to the first chamfer 213 of the outer cap 210 and may be used for welding.

[0077] The lower region 232 may be formed to extend from a lower end of the upper region 231 toward the inside of the housing 110. The lower region 232 may be formed to accommodate the inner cap 220. In one embodiment, the inner surface 232a of the lower region 232 may be formed to extend obliquely to correspond to the outer surface 223 of the inner cap 220. Accordingly, the lower region 232 may have a fourth diameter D4 in an upper portion thereof and may have a fifth diameter D5 in a lower portion thereof. The fourth diameter D4 corresponds to a diameter of an upper portion of the inner cap 220, and the fifth diameter D5 corresponds to a diameter of a lower portion of the inner cap 220. Additionally, the lower region 232 may have a second height H2 corresponding to an up-down height of the inner cap 220.

[0078] In one embodiment, a step surface 234 may be formed between the lower region 232 and the upper region 231. The step surface 234 may be formed in a boundary between the upper region 231 having the first diameter D1 and an upper end of the lower region 232 having the fourth diameter D4. The step surface 234 may have a predetermined width due to a difference between the first and fourth diameters D1 and D4 and may be formed to extend in a circumferential direction in a boundary between the upper region 231 and the lower region 232.

[0079] The step surface 234 may provide a support structure for the outer cap 210. That is, the outer cap 210 may be supported by seating a lower surface of the upper portion 211 on the step surface 234. Accordingly, the step surface 234 may function to guide a mounting position of the outer cap 210. In some other embodiments, the step surface 234 may be used to support the inner cap 220. Fig. 3A and the like described below illustrate a case where the inner cap 220 is supported by the step surface 234 to guide the mounting position.

[0080] Fig. 2C is a schematic assembly flow diagram of the Fig. 2A illustrated sealing member.

[0081] With reference to (a) of Fig. 2C, the inner cap 220 may first be positioned within the electrolyte injection port 230. In one embodiment, the inner cap 220 may be supported by depositing a sloped outer surface 223 on the inner surface 232a of the lower region 232. This may improve ease of assembly.

[0082] With reference to (b) of Fig. 2C, the outer cap 210 may be attached to the inner cap 220. The outer cap 210 may be attached to the inner cap 220 while the insertion portion 214 is inserted into the insertion path 221 of the inner cap 220. Specifically, the outer cap 210 may be inserted into and attached to the insertion path 221 while the first spiral portion 215 formed in the insertion portion 214 is screw-coupled to the second spiral portion 222 formed in the insertion path 221 of the inner cap 220. According to the screw coupling, the outer cap 210 may enter downward toward the inside of the insertion path 221 while rotating about a longitudinal axis. In addition, the outer cap 210 may enter while the inner cap 220 is gradually compressed according to an inclination of an inner surface of the insertion path 221.That is, the outer cap 210 can be inserted in the longitudinal direction while the inner cap 220 is gradually compressed in a transverse direction. Accordingly, the outer surface 223 of the inner cap 220 can be firmly attached to the inner surface 232a of the lower region 232.

[0083] When the insertion portion 214 is fully inserted into the insertion path 221, the upper portion 211 of the outer cap 210 may be disposed in the upper region 231 of the electrolyte injection port 230. In one embodiment, the upper portion 211 of the outer cap 210 may be disposed to form a plane generally corresponding to an upper surface of the cap plate 130. Additionally, the first chamfer 213 of the outer cap 210 and the second chamfer 233 of the cap plate 130 may be disposed to correspond to each other, thereby forming a groove for welding and bonding. The outer cap 210 may be welded to the cap plate 130 at the first and second chamfers 213 and 233 and may be firmly fixed to the cap plate 130.

[0084] In one embodiment, the inner cap 220 may be formed to have different degrees of elastic compression at each position in the up-down direction by the inclination of the insertion path 221. That is, a lower region of the inner cap 220, in which a diameter of the insertion path 221 is formed to be relatively small, may be elastically compressed more in the transverse direction than the upper region. For reference, in an embodiment described below, an inner cap 320 may have an upper region thereof that is elastically compressed more in a transverse direction than a lower region thereof. In any case, however, the inner caps 220 and 320 may be elastically compressed to some extent in an initial state and may be firmly adhered to the inner surfaces 232a and 332a of the electrolyte injection port.

[0085] Fig. 3A is a schematic cross-sectional view of a sealing member based on another embodiment. Fig. 3B(a) and Fig. 3B(b) are schematic assembly state diagrams of the Fig. 3A illustrated sealing member.

[0086] For convenience, the following embodiments will be described with an emphasis on differences from the aforementioned embodiments.

[0087] With reference to Fig. 3A and Fig. 3B, a sealing member 300 according to the present embodiment may include an outer cap 310 and an inner cap 320.

[0088] The outer cap 310 may form an upper structure of the sealing member 300. Additionally, the outer cap 310 may include an upper portion 311 having a tool attachment portion 312 formed therein and an insertion portion 314 extending from the upper portion 311. This is generally similar to the embodiment described above.

[0089] In one embodiment, the insertion portion 314 may be formed such that a diameter thereof decreases from an upper end to a lower end. This is compared to the above-described embodiment in which the diameter of the insertion path 221 is formed to be smaller. Specifically, the upper portion 311 of the outer cap 310 may have a first diameter D1, and the insertion portion 314 may have a second diameter D2 that is smaller than the first diameter D1 by a predetermined amount in an upper end. In addition, the insertion portion 314 may have a third diameter D3 that is smaller than the second diameter D2 by a predetermined amount in a lower portion, and may be formed such that a diameter thereof gradually decreases from the upper end to the lower end.The shape of the insertion portion 314 as described above may allow the inner cap 320 to be elastically compressed in the transverse direction as the insertion portion 314 enters an insertion path 321.

[0090] In some implementations, a first spiral portion 315 may be formed on a lateral periphery of the insertion portion 314. The first spiral portion 315 may be formed to extend along an outer surface of the insertion portion 314 along the shape of the insertion portion 314 described above.

[0091] The inner cap 320 may be formed of an elastic material and may be attached to a lower portion of the outer cap 310. The inner cap 320 may be in close contact with an inner surface 332a of an electrolyte injection port 330 and may be elastically deformed according to the attachment of the outer cap 310. This is generally similar to the embodiments described above.

[0092] Additionally, the inner cap 320 may include an insertion path 321, and the insertion path 321 may be formed to vertically penetrate a center of the inner cap 320. In one embodiment, the insertion path 321 of the inner cap 320 has a third diameter D3 corresponding to a lower end of the insertion portion 314 and may be formed to extend upward and downward. Additionally, a second spiral portion 322 corresponding to the first spiral portion 315 of the outer cap 310 may be formed on an inner surface of the inner cap 320 surrounding the insertion path 321. Accordingly, the outer cap 310 and the inner cap 320 may be mutually joined by screw coupling between the first and second spiral portions 315 and 322.

[0093] In some implementations, the inner cap 320 may include an outer surface 323, and the outer surface 323 may be attached to the inner surface 332a of the electrolyte injection port 330. In one embodiment, the outer surface 323 of the inner cap 320 may be formed to extend vertically to have a predetermined diameter. That is, the outer surface 323 of the inner cap 320 may be formed to extend vertically to have a fourth diameter D4. This is compared to the outer surface 223 in the embodiment described above, where the diameter thereof is formed to be smaller. The fourth diameter D4 may be formed to be larger by a predetermined degree than the third diameter D3 of the insertion path 321 and smaller by a predetermined degree than the first diameter D1 of the upper portion 311 of the outer cap 310.

[0094] In the case described above, the inner cap 320 may include a flange 324. The flange 324 may be formed to extend a predetermined width from the upper portion of the inner cap 320 in the transverse direction. An outer periphery of the flange 324 may have a first diameter D1 corresponding to the upper end 311 of the outer cap 310. Accordingly, the flange 324 may be supported by being seated on a stepped surface 334 of the electrolyte injection port 330.

[0095] The flange 324 of the inner cap 320 can replace the inclined outer surface 223 of the above-described embodiment and can support the inner cap 320 at a mounting position. That is, the inner cap 320 of this embodiment can be supported at a predetermined mounting position in the electrolyte injection port 330 by the flange 324 because the outer surface 323 is formed to extend vertically upward and downward.

[0096] Additionally, the flange 324 of the inner cap 320 may form an additional sealing structure between the upper portion 311 of the outer cap 310 and an upper surface of the inner cap 320. That is, the flange 324 of the inner cap 320 may be disposed between a lower surface of the upper portion 311 and an upper surface of the inner cap 320, thereby acting as a type of sealing structure that is elastically compressed according to the insertion of the outer cap 310.

[0097] In some embodiments, the cap plate 130 may include an electrolyte injection port 330.

[0098] In one embodiment, the electrolyte injection opening 330 may have a structure and shape corresponding to the outer cap 310 and inner cap 320 described above. In particular, the electrolyte injection opening 330 may include an upper region 331 and a lower region 332. The upper region 331 may have a first diameter D1 corresponding to the upper portion 311 of the outer cap 310, and the lower region 332 may have a fourth diameter D4 corresponding to the outer surface 323 of the inner cap 320. In one embodiment, the lower region 332 does not include an inclined surface, unlike the embodiment described above. Additionally, depending on a difference between the first diameter D1 and the fourth diameter D4, a step surface 334 may be formed between the upper region 331 and the lower region 332.

[0099] Looking at the assembly sequence of the sealing member 300 described above, the inner cap 320 may first be disposed in the electrolyte injection port 330. In one embodiment, the inner cap 320 may be disposed in the electrolyte injection port 330, while the flange 324 is recessed at an upper end thereof and supported on the step surface 334.

[0100] Then, the outer cap 310 can be fixed to the inner cap 320. In the outer cap 310, while the first and second spiral sections 315 and 322 are screw-coupled, the insertion section 314 can be inserted into and fixed to the insertion path 321. In addition, the outer cap 310 can gradually compress the inner cap 320 in the transverse direction according to the inclination of the outer surface 323 of the insertion section 314 and can be inserted into and fixed to the insertion path 321. Accordingly, the outer surface 323 of the inner cap 320 can be firmly attached to the inner surface 332a of the lower region 332.

[0101] In some implementations, when the insertion portion 314 is fully inserted into the insertion path 321, the outer cap 310 may be welded to the cap plate 130 at the first and second bevels 313 and 333 and may be firmly fixed to the cap plate 130.

[0102] Fig. 4A is a schematic cross-sectional view of a sealing member based on another embodiment. Fig. 4B(a) and Fig. 4B(b) are schematic assembly flow diagrams of the Fig. 4A illustrated sealing member.

[0103] For reference, in the following embodiments, the simplicity of electrolyte injection may be more considered compared to the aforementioned embodiments.

[0104] With reference to Fig. 4A and Fig. 4B, a sealing member 400 may include an outer cap 410 based on one embodiment.

[0105] The outer cap 410 may include a first insertion portion 414a. The first insertion portion 414a may be configured to extend downwardly from a bottom surface of the outer cap 410 by a predetermined length. In one embodiment, the first insertion portion 414a is illustrated in the form of a circular column with a predetermined diameter that extends upwardly and downwardly.

[0106] The outer cap 410 may include a second insertion portion 414b. The second insertion portion 414b may be formed to protrude downward from the bottom surface of the outer cap 410 by a predetermined length. The second insertion portion 414b may be formed to be shorter than the first insertion portion 414a by a predetermined amount. That is, the first insertion portion 414a may have a first vertical length L1, and the second insertion portion 414b may have a second length L2 that is shorter than the first length L1 by a predetermined length.

[0107] Additionally, the second insertion portion 414b may be spaced apart from the first insertion portion 414a by a predetermined gap G1 in the transverse direction. The gap G1 may be used for attachment to a protruding rib 425 described below. Accordingly, the gap G1 may be formed to correspond to a thickness T1 of the protruding rib 425. Additionally, the second insertion portion 414b may be formed to extend in the circumferential direction centered on the first insertion portion 414a. In other words, the second insertion portion 414b may have a circular ring shape in a plane.

[0108] In addition, a first chamfer 413 for welding to the cap plate 130 may be formed in a periphery of an upper end of the outer cap 410.

[0109] In some implementations, the sealing member 400 may include an inner cap 420.

[0110] The inner cap 420 may include a first insertion path 421a. The first insertion path 421a may be formed to extend upward and downward from the center of the inner cap 420 and penetrate the inner cap 420 upward and downward. The first insertion path 421a may be connected to the first insertion portion 414a of the outer cap 410. The first insertion portion 414a may be inserted into and fixed to an upper end of the first insertion path 421a, and the first insertion path 421a may be closed by the first insertion portion 414a. The first insertion path 421a may have a cross-sectional shape and size corresponding to the first insertion portion 414a, so that the first insertion path 421a can be closed by the first insertion portion 414a.In one embodiment, the first insertion path 421a may have a circular shape and size corresponding to the cross-sectional shape of the first insertion portion 414a.

[0111] The inner cap 420 may include a protruding rib 425 forming the first insertion path 421a. The protruding rib 425 may be formed to extend upwardly from a lower surface of the inner cap 420 by a predetermined height. In one embodiment, the protruding rib 425 may have a circular sleeve shape that extends upwardly and downwardly. In addition, the first insertion path 421a may be formed at a center of the protruding rib 425. The first insertion path 421a may be formed to extend upwardly and downwardly by penetrating the center of the protruding rib 425. The protruding rib 425 may have a thickness T1 corresponding to the gap G1 of the above-described first and second insertion portions 414a and 414b, and may be inserted into and fixed to the gap G1.

[0112] In one embodiment, a vertical height H3 of the protruding rib 425 may be formed to be a predetermined height smaller than a total height H4 of the inner cap 420. Accordingly, an upper end of the protruding rib 425 may have a predetermined gap G2 and may be positioned lower than an upper end of the inner cap 420. The gap G2 may function as a passage for conducting the electrolyte overflowing from the first introduction path 421a to a second introduction path 421b.

[0113] In some implementations, the inner cap 420 may include a second insertion path 421b. The second insertion path 421b may be disposed on an outer periphery of the first insertion path 421a with the protruding rib 425 disposed therebetween. The second insertion path 421b may be coupled to the second insertion portion 414b. In one embodiment, the second insertion path 421b may have a circular ring shape in a plane corresponding to the second insertion portion 414b.

[0114] In addition, the second insertion path 421b may have a third vertical length L3. A vertical length of the second insertion path 421b may be defined as a length from a top surface of the protruding rib 425 to a bottom surface of the second insertion path 421b. Here, the third length L3 may be formed to be longer than the second length L2 of the second insertion portion 414b by a predetermined length. That is, the second insertion path 421b may be formed to be deeper than a protruding length of the second insertion portion 414b by a predetermined amount. Accordingly, the second insertion portion 414b may be arranged to have a predetermined gap G3 in the second insertion path 421b.

[0115] In some implementations, the inner cap 420 may include a vent hole 426. The vent hole 426 may be penetrated and formed upwardly and downwardly on the lower surface of the inner cap 420 so as to connect to the second introduction path 421b. The vent hole 426 may provide a passage for the movement of gas or the like between the second introduction path 421b and a lower side of the inner cap 420 (i.e., an interior of the housing 110). A plurality of vent holes 426 may be provided as needed, and the plurality of vent holes 426 may be spaced apart from each other by a predetermined interval along the second introduction path 421b.

[0116] In some embodiments, the cap plate 130 may include an electrolyte injection port 430.

[0117] The electrolyte injection hole 430 may be penetrated and formed in the cap plate 130 to provide a passage for injecting the electrolyte into the interior of the housing 110.

[0118] In one embodiment, the electrolyte injection opening 430 may have a size and shape that generally correspond to the outer periphery of the inner cap 420. Additionally, a shoulder groove 435 may be provided on an outer periphery of the electrolyte injection opening 430. A flange 424 of the inner cap 420 may be seated and supported in the shoulder groove 435. A second chamfer 433 may be formed in an upper side of the shoulder groove 435. The second chamfer 433 may be arranged to correspond to the first chamfer 413 of the outer cap 410 and may be used for weld bonding.

[0119] When looking at an operation of the sealing member 400 described above, first, as shown in (a) of Fig. 4B, the inner cap 420 may be attached to the electrolyte injection port 430. The inner cap 420 may be supported by the electrolyte injection port 430, while the flange 324 is seated and supported in the seat groove 435. In some cases, the inner cap 420 may be fixed to the electrolyte injection port 430 by tack welding or the like.

[0120] In the above-described state, the electrolyte can be injected into the housing 110 through the first introduction path 421a. Following the electrolyte injection, the gas in the housing 110 can be discharged to the outside through the discharge hole 426. In one embodiment, an electrolyte injection path and an internal gas discharge path can be separated, thereby inducing uniform injection of the electrolyte and uniform discharge of the internal gas at the same time. In addition, the electrolyte excessively injected through the first introduction path 421a can overflow the protruding rib 425 and flow into the second introduction path 421b, and the injected electrolyte can be recovered into the housing 110 through the discharge hole 426.

[0121] With reference to (b) of Fig. 4B, the inner cap 420 can then be sealed by the outer cap 410. The outer cap 410 can be attached to an upper portion of the inner cap 420 while the first insertion portion 414a is inserted into the first insertion path 421a of the inner cap 420 and the second insertion portion 414b is inserted into the second insertion path 421b of the inner cap 420. When the outer cap 410 is fully inserted therein, the outer cap 410 can be welded to the cap plate 130 at the first and second chamfers 413 and 433 and can be firmly fixed to the cap plate 130.

[0122] In some implementations, in a state where the outer cap 410 is attached as described above, the second insertion portion 414b of the outer cap 410 may be spaced from the inner cap 420 by a predetermined gap G3. The gap G3 may be formed by a length difference between the second insertion path 421b and the second insertion portion 414b. In addition, the gap G3 may be connected to the exhaust hole 426 of the inner cap 420. The above gap G1 may function as a means for buffering the internal pressure transmitted to the outer cap 410 after the outer cap 410 is attached. Accordingly, an external force transmitted to a weld portion of the outer cap 410 can be mitigated, and fatigue failure of the sealing member 400 due to repeated stress can be prevented.

[0123] Fig. 5A is a schematic cross-sectional view of a sealing member based on another embodiment. Fig. 5B(a) and Fig. 5B(b) are schematic assembly flow diagrams of the Fig. 5A illustrated sealing member.

[0124] With reference to Fig. 5A and Fig. 5B, a sealing member 500 based on one embodiment may include an outer cap 510 and an inner cap 520.

[0125] The outer cap 510 may be formed in a similar manner to the outer caps 210, 310, and 410 of the above-described embodiment. A first insertion portion 514a may be provided on a lower surface of the outer cap 510, and a second insertion portion 514b may be provided on an outer side centered on the first insertion portion 514a. The second insertion portion 514b may have a length shorter than a length of the first insertion portion 514a by a predetermined amount and may be formed to extend into a circular ring shape on a plane centered on the first insertion portion 514a. In addition, a first chamfer 513 may be formed on a periphery of an upper end of the outer cap 510.

[0126] In one embodiment, the inner cap 520 may be integrated with the cap plate 130. That is, the inner cap 520 may be formed as a portion of the cap plate 130.

[0127] The inner cap 520 may be generally similar to the inner caps 220, 320, and 420 of the above-described embodiment, except that the inner cap 520 is integrated with the cap plate 130. The inner cap 520 may have a protruding rib 525 protruding from a bottom surface by a predetermined height, and the protruding rib 525 may include a first insertion path 521a into which the first insertion portion 514a is inserted and secured. Unlike the first insertion path 421a of the above-described embodiment, the first insertion path 521a of this embodiment has a shape similar to a hole. In one embodiment, the first insertion path 521a may be used as an electrolyte injection port for injecting the electrolyte into the housing 110.

[0128] Additionally, the inner cap 520 may include a second insertion path 521b formed on an outer periphery of the protruding rib 525. The second insertion path 521b may be formed to be deeper than a protruding length of the corresponding second insertion portion 514b by a predetermined depth, thereby forming a gap G3 from the second insertion portion 514b. Additionally, a vent hole 526 providing a passage for gas and the like may be formed in a lower end of the second insertion path 521b. Additionally, a second chamfer 533 may be formed in a connecting portion between the inner cap 520 and the cap plate 130.

[0129] With reference to (a) of Fig. 5B, the sealing member 500 described above can be used to inject electrolyte or exhaust gas through the inner cap 520 integrated with the cap plate 130.

[0130] With reference to (b) of Fig. 5B, the inner cap 520 can then be sealed by the outer cap 510. Similar to the embodiment described above, the outer cap 510 can be attached to an upper portion of the inner cap 520, or the cap plate 130 as the first insertion portion 514a is inserted into the first insertion path 521a, and the second insertion portion 514b is inserted into the second insertion path 521b. In addition, the outer cap 510 can be welded to the cap plate 130 at the first and second chamfers 513 and 533 and can be firmly fixed to the cap plate 130.

[0131] In some implementations, in some other embodiments, the electrolyte injection port and the sealing members 200 to 500 as described above may be arranged in components of the secondary battery 100 other than the cap plate 130. Alternatively, part or all of the cap plate 130 may be integrated with other components of the secondary battery 100, and the electrolyte injection port and the like may be arranged in other integrated components. For example, the electrolyte injection port may be arranged at a predetermined position of the casing 110, and the sealing members 200 to 500 of the above-described embodiments may be used to seal the electrolyte injection port arranged in the casing 110 in this way.

[0132] As described above, the secondary battery according to embodiments of the disclosed technology may provide a sealing member for sealing the electrolyte injection port. The sealing member according to some embodiments of the disclosed technology may include an outer cap and an inner cap, and the inner cap may be configured to be elastically compressed by the outer cap. Accordingly, the sealing member can implement a more convenient sealing structure in the casing. In addition, the sealing member can also improve the safety of the secondary battery by responding to changes in the internal pressure of the casing.

[0133] The sealing member according to other embodiments of the disclosed technology may include an outer cap and an inner cap, and a first insertion path and a second insertion path may be formed in the inner cap. The first insertion path may function as a passage for injecting the electrolyte, and the second insertion path may function as a passage for discharging gas within the housing. Accordingly, the first and second injection paths can implement a more uniform injection of the electrolyte.

[0134] The disclosed technology can be implemented in the field of secondary batteries or rechargeable batteries, which are widely used in electric vehicles, uninterruptible power supplies, battery storage power plants, and others, including battery power storage for solar panels, wind energy generators, and other green technology power generators. In particular, the disclosed technology can be implemented in some applications to provide secondary batteries that can improve battery reliability and performance and, accordingly, mitigate climate change.Secondary batteries based on the disclosed technology can be used to address various adverse effects, such as air pollution and greenhouse gas emissions, by powering electric vehicles (EVs) as alternatives to vehicles with fossil fuel-based engines, and by providing battery-based energy storage systems (ESS) to store renewable energy, such as solar and wind energy.

[0135] Only specific examples of implementations of particular embodiments are described. Variations, improvements, and extensions of the disclosed embodiments and other embodiments may be made based on the disclosure of this patent document.

[0136] The present disclosure also relates to the following aspects.

[0137] Aspect 1) A secondary battery comprising: a casing in which an electrode assembly is housed therein; a cap plate that seals an opening of the casing; an electrolyte injection port provided in the cap plate; a sealing member that seals the electrolyte injection port, and wherein the sealing member includes: an inner cap that is fixed to an inner surface of the electrolyte injection port; and an outer cap that is inserted into and fixed to the inner cap and is configured to elastically compress the inner cap toward the inner surface.

[0138] Aspect 2) In aspect 1, wherein the outer cap is coupled to the inner cap by means of screws and is configured to elastically compress the inner cap gradually toward the inner surface while entering an inside of the inner cap by screw coupling.

[0139] Aspect 3) In aspect 1 or 2, wherein the inner cap includes an insertion path into which the outer cap is inserted, the insertion path being formed such that a diameter thereof gradually decreases in an insertion direction of the outer cap.

[0140] Aspect 4) In any one of aspects 1 to 3, wherein the inner cap includes an outer surface fixed to the inner surface, the outer surface being formed such that a diameter thereof gradually decreases in an insertion direction of the outer cap.

[0141] Aspect 5) In aspect 4, wherein the inner surface is formed such that a diameter thereof gradually decreases in the insertion direction of the outer cap to correspond to the outer surface, and the inner cap is formed such that it is supported in the electrolyte injection port by seating the outer surface on the inner surface.

[0142] Aspect 6) In any one of aspects 1 to 5, wherein the outer cap includes an insertion portion that is inserted into the inner cap, the insertion portion being formed such that a diameter thereof gradually decreases in an insertion direction of the outer cap.

[0143] Aspect 7) In any one of aspects 1 to 6, wherein the inner cap is formed such that an outer surface thereof has a predetermined diameter and extends upward and downward, wherein a flange supported by a step surface formed in the electrolyte injection port is provided in an upper end of the outer surface.

[0144] Aspect 8) In any one of aspects 1 to 7, wherein the inner cap is formed such that a degree of elastic compression in a transverse direction in an upper region and a lower region varies according to an insertion direction of the outer cap.

[0145] Aspect 9) In any one of aspects 1 to 8, wherein at least a part of the inner cap is formed of an elastic material, and the outer cap is formed of a hard material compared to the inner cap, and is welded and fixed to the cap plate.

[0146] Aspect 10) In any one of aspects 1 to 9, wherein the cap plate includes a first cap plate disposed on one side of the housing and a second cap plate disposed on the other side of the housing, and the electrolyte injection port includes a first electrolyte injection port enclosed in the first cap plate and / or a second electrolyte injection port enclosed in the second cap plate.

[0147] Aspect 11) A secondary battery comprising: a casing in which an electrode assembly is housed therein; a cap plate that seals an opening of the casing; an electrolyte injection port enclosed in the cap plate; and a sealing member that seals the electrolyte injection port, the sealing member including: an inner cap having a first introduction path that provides an injection path of an electrolyte and a second introduction path that provides an exhaust path of internal gas when the electrolyte is injected, and an outer cap having a first introduction portion that is inserted into and fixed to the first introduction path so as to close the first introduction path, and a second introduction portion that is inserted into and fixed to the second introduction path.

[0148] Aspect 12) In aspect 11, wherein the inner cap includes a protruding rib extending from a lower surface of the inner cap by a predetermined height to form the first introduction path, the protruding rib being formed such that an upper end thereof has a predetermined gap and is arranged to be lower than an upper end of the inner cap, and being configured to guide the electrolyte overflowing from the first introduction path through the gap to the second introduction path.

[0149] Aspect 13) In aspect 11 or 12, wherein the inner cap includes a discharge hole communicating with the second insertion path, and the second insertion portion is spaced from the discharge hole by a predetermined gap, and the gap is formed to buffer internal pressure transmitted to the outer cap.

[0150] Aspect 14) In any one of aspects 11 to 13, wherein the inner cap has a flange that is seated and supported in a seat groove provided in the cap plate, or a part or the whole of the inner cap is integrated with the cap plate.

[0151] Aspect 15) In any one of aspects 11 to 14, wherein the outer cap includes a first chamfer arranged to correspond to a second chamfer provided on the cap plate and welded and bonded between the cap plate and the outer cap.

Claims

[1] Secondary battery, comprising: a housing structured to house an electrode assembly; a cap plate disposed on the housing to seal an opening of the housing; an electrolyte injection port disposed in the cap plate for injecting an electrolyte into an interior space of the housing; a sealing member configured to seal the electrolyte injection port, where the sealing member includes: an inner cap attached to an inner surface of the electrolyte injection port; and an outer cap inserted into and secured to the inner cap and configured to elastically compress the inner cap toward the inner surface. [2] The secondary battery according to claim 1, wherein the outer cap is coupled to the inner cap by means of screws and is configured to gradually elastically compress the inner cap toward the inner surface of the electrolyte injection port while the outer cap moves inward by the screw coupling. [3] Secondary battery according to claim 1 or 2, wherein the inner cap includes an insertion path configured to receive the outer cap, wherein a diameter of the insertion path gradually decreases in an insertion direction of the outer cap. [4] Secondary battery according to one of claims 1 to 3, wherein the inner cap includes an outer surface of the electrolyte injection port which is attached to the inner surface of the electrolyte injection port, wherein a diameter of the outer surface gradually decreases in an insertion direction of the outer cap. [5] Secondary battery according to claim 4, wherein a diameter of the inner surface of the electrolyte injection port gradually decreases in the insertion direction of the outer cap so as to correspond to the outer surface of the electrolyte injection port, and the inner cap is supported in the electrolyte injection hole by aligning the outer surface of the electrolyte injection hole with the inner surface of the electrolyte injection hole. [6] Secondary battery according to one of claims 1 to 5, wherein the outer cap includes an insertion portion which is inserted into the inner cap, wherein a diameter of the insertion portion gradually decreases in an insertion direction of the outer cap. [7] Secondary battery according to one of claims 1 to 6, wherein the inner cap is formed such that an outer surface of the electrolyte injection opening has a predetermined diameter extending both upward and downward, wherein a flange supported by a step surface formed in the electrolyte injection hole is disposed at an upper end of the outer surface of the electrolyte injection hole. [8] A secondary battery according to any one of claims 1 to 7, wherein the inner cap is structured so that a degree of elastic compression in a transverse direction between an upper region and a lower region varies depending on an insertion direction of the outer cap. [9] Secondary battery according to one of claims 1 to 8, wherein at least a portion of the inner cap includes an elastic material, and the outer cap contains a harder material than the inner cap and is welded and fixed to the cap plate. [10] Secondary battery according to one of claims 1 to 9, wherein the cap plate includes a first cap plate disposed on a first side of the housing and a second cap plate disposed on a second side of the housing opposite the first side, and the electrolyte injection port includes at least one of: a first electrolyte injection port enclosed in the first cap plate; or a second electrolyte injection port enclosed in the second cap plate. [11] Secondary battery comprising: a housing structured to house an electrode assembly; a cap plate disposed on the housing to seal an opening of the housing; an electrolyte injection port enclosed in the cap plate for injecting an electrolyte into an interior space of the housing; and a sealing member configured to seal the electrolyte injection port, where the sealing member includes: an inner cap including: a first introduction path to provide an injection path for an electrolyte; and a second introduction path to provide an exhaust path for internal gas during electrolyte injection, and an outer cap including: a first insertion portion inserted into and secured to the first insertion path to seal the first insertion path; and a second insertion portion inserted into and secured to the second insertion path. [12] Secondary battery according to claim 11, wherein the inner cap includes a protruding rib extending upward from a lower surface of the inner cap by a predetermined height to form the first insertion path, wherein the protruding rib is formed such that an upper end of the protruding rib includes a predetermined gap and is arranged to be lower than an upper end of the inner cap, and wherein the protruding rib is configured to guide the electrolyte overflowing from the first introduction path through the gap into the second introduction path. [13] Secondary battery according to claim 11 or 12, wherein the inner cap includes a drain hole communicating with the second insertion path, and the second insertion portion is spaced from the discharge hole by a predetermined gap, the gap being configured to buffer internal pressure transmitted to the outer cap. [14] Secondary battery according to one of claims 11 to 13, wherein the inner cap includes a flange placed and supported within a set-off groove provided in the cap plate, or at least a portion of the inner cap is integrated with the cap plate. [15] A secondary battery according to any one of claims 11 to 14, wherein the outer cap includes a first bevel aligned with a second bevel disposed on the cap plate and welded and bonded to the cap plate.

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