Secondary battery

Abstract

A secondary battery is disclosed. The secondary battery includes: an electrode assembly including a first electrode plate, a separator, and a second electrode plate; a can accommodating the electrode assembly, the lower end of the can being open and being electrically connected to the second electrode plate; a first current collector plate between a top surface of the electrode assembly and the can, and electrically connected to the first electrode plate; and a terminal portion passing through a top surface of the tank, a lower end of the terminal portion being electrically and mechanically coupled to a top surface of the first current collector plate. A terminal liquid injection hole into which an electrolyte is injected extends through the terminal portion.

Description

[0001] This application claims the priority and benefit of Korean Patent Application No. 10-2024-0013085, filed with the Korean Intellectual Property Office on January 29, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] Aspects of embodiments of the present disclosure relate to secondary batteries. Background Art

[0003] A cylindrical secondary battery generally includes a cylindrical electrode assembly, a cylindrical can that houses the electrode assembly and an electrolyte, and a cap assembly that is coupled to an opening at one side of the can to seal the can, the cap assembly being electrically connected to the electrode assembly to electrically connect an external device to the electrode assembly.

[0004] In a battery module including a plurality of secondary batteries connected to each other, bus bars are respectively connected to the upper and lower portions (e.g., upper end and lower end) of the secondary batteries, and the connection and housing structure is complex, and the processing time increases.

[0005] To alleviate these concerns, the can may have a terminal hole at each of one opening side and the opposite side, and a positive electrode riveted terminal and the can are coupled inside the terminal hole to insulate from each other. When using this battery configuration, the bus bars are disposed on the same surface of the secondary battery to more easily facilitate the connection of the bus bars in the secondary battery module.

[0006] However, welding is generally used to connect the riveted terminal to a current collector plate at the core of the electrode assembly, and thus, metal foreign substances such as smoke or spatter may be generated inside the battery. As a result, an additional dust removal operation is generally performed to remove the metal foreign substances (if any). In addition, the electrode assembly may be damaged due to welding heat.

[0007] In addition, the electrolyte is injected through a liquid injection port on the cover plate side. Due to the welding of the wing portion of the negative electrode current collector plate, the sealing point may change during injection, and due to an increase in the injection amount and the area of the crimped portion, the remaining electrolyte increases, which may cause the electrolyte to remain on the crimped portion and the wound portion of the negative electrode current collector plate.

[0008] The above information disclosed in the background art section provides the background of the present disclosure and is used to improve the understanding of the background of the present disclosure, and thus may include information that does not constitute related (or prior) art. Summary of the Invention

[0009] Embodiments of the present disclosure provide a secondary battery having an improved terminal and liquid injection structure.

[0010] According to an embodiment of the present disclosure, a secondary battery includes: an electrode assembly including a first electrode plate, a separator, and a second electrode plate; a can that houses the electrode assembly, the lower end of the can being open and electrically connected to the second electrode plate; a first current collector plate located between the top surface of the electrode assembly and the can and electrically connected to the first electrode plate; and a terminal portion that passes through the top surface of the can, the lower end of the terminal portion being electrically and mechanically coupled to the top surface of the first current collector plate. A terminal liquid injection hole through which an electrolyte is injected extends through the terminal portion.

[0011] The terminal portion may include: a riveting terminal coupled to the top surface of the can; and an insulator located between the can and the riveting terminal to insulate the can and the riveting terminal from each other.

[0012] The can may have a top surface having a flat plate shape and a terminal hole, and a side surface extending downward from the edge of the top surface of the can, the terminal hole passing through a central portion of the top surface of the can. The riveting terminal may be located in the terminal hole.

[0013] The riveting terminal may include: a head located outside the top surface of the can; and a body inserted into the terminal hole and extending toward the inside of the can.

[0014] The planar dimension of the head may be larger than the planar dimension of the body.

[0015] The body may have: an upper body portion connected to the head and located within the terminal hole in the top surface of the can; and a lower body portion extending downward from the upper body portion and located inside the can.

[0016] The lower body portion may have an outer diameter larger than the outer diameter of the upper body portion.

[0017] The terminal liquid injection hole may be located in the body of the riveting terminal.

[0018] The first current collector plate may have an injection hole into which an electrolyte is injected, and the injection hole in the first current collector plate may correspond to the position of the terminal hole in the riveting terminal.

[0019] The terminal liquid injection hole may have an inner diameter equal to the inner diameter of the injection hole in the first current collector plate.

[0020] The riveting terminal may have a welding groove having a depth in a downward direction from its top surface.

[0021] In a state where the top surface of the first current collector plate is in contact with the bottom surface of the body, the first current collector plate may be welded to the riveting terminal outside the riveting terminal through the welding groove such that the weld bead is located inside the welding groove.

[0022] The welding groove may pass through a central portion of the head to extend downward from the upper portion of the body.

[0023] The upper inner diameter of the welding groove can be larger than its lower inner diameter.

[0024] The terminal liquid injection hole can extend from the bottom surface of the welding groove to the bottom surface of the main body.

[0025] The terminal liquid injection hole can have an inner diameter smaller than the lower inner diameter of the welding groove.

[0026] In a state where the top surface of the first current collector plate is in contact with the bottom surface of the main body, the first current collector plate can be welded outside the riveted terminal through the welding groove such that the weld bead is located in the welding groove.

[0027] The terminal portion can have a terminal flat portion on the top surface of the riveted terminal to cover the top surface of the riveted terminal.

[0028] The terminal flat portion can have a planar dimension smaller than the planar dimension of the head of the riveted terminal.

[0029] The terminal flat portion can have a stepped portion on its upper edge.

[0030] In a state where the top surface of the riveted terminal is in contact with the bottom surface of the terminal flat portion, the riveted terminal can be welded to the stepped portion on the upper edge of the terminal flat portion such that the weld bead is on the stepped portion along the circumference of the riveted terminal.

[0031] The welding area of the terminal flat portion can have a diameter smaller than the outer diameter of the head of the riveted terminal.

[0032] The terminal flat portion can have a protrusion protruding in the direction towards the welding groove in the riveted terminal and be joined to the welding groove of the riveted terminal.

[0033] The protrusion of the terminal flat portion can have a tapered shape with an outer diameter gradually decreasing in the protruding direction.

[0034] The protrusion of the terminal flat portion can correspond to the shape of the welding groove.

[0035] The protrusion of the terminal flat portion can partially fill the welding groove.

[0036] The protrusion of the terminal flat portion can have the same shape as the welding groove to be in close contact with the welding groove.

[0037] The protrusion of the terminal flat portion can include an additional protrusion protruding in the direction towards the terminal liquid injection hole and be joined to the terminal liquid injection hole.

[0038] The additional protrusion of the terminal flat portion can have an outer diameter corresponding to the inner diameter of the terminal liquid injection hole.

[0039] The additional protrusion of the terminal flat portion may have an outer diameter equal to the inner diameter of the terminal liquid injection hole to be in close contact with the terminal liquid injection hole.

[0040] The insulator may include: a first insulator located between the outer end of the riveted terminal and the top surface of the can; a second insulator located at the side of the terminal hole in the top surface of the can and extending around the periphery of the terminal hole; and a third insulator located between the inner surface of the top surface of the can and the inner end of the riveted terminal.

[0041] One end of the first insulator may protrude beyond the head.

[0042] The first insulator may have a planar dimension larger than the planar dimension of the head.

[0043] The third insulator may have a planar dimension larger than the planar dimension of the first current collector plate.

[0044] The third insulator may cover the inner surface of the top surface of the can.

[0045] The uncoated portion of the positive electrode where the positive electrode active material is not coated may protrude upward from the first electrode plate, and the uncoated portion of the negative electrode where the negative electrode active material is not coated may protrude downward from the second electrode plate.

[0046] The secondary battery may further include a second current collector plate. The can may have a top surface having a flat plate shape and a terminal hole, and a side surface extending downward from the edge of the top surface, and the terminal hole passes through the central portion of the top surface of the can. The second current collector plate may be adjacent to one end of the side surface and electrically connected to the second electrode plate and the side surface.

[0047] The secondary battery may further include a cover plate that is coupled to the side surface to seal the lower end of the can and is insulated from the side surface.

[0048] The side surface may have: a curled portion including an inwardly recessed portion of the side surface; and a crimped portion including the inwardly bent lower end of the side surface. The cover plate may be located between the curled portion and the crimped portion.

[0049] The secondary battery may further include a gasket located between the cover plate and the side surface.

[0050] The second current collector plate may be located between the curled portion and the gasket and in contact with the curled portion.

[0051] The riveted terminal, the first current collector plate, and the terminal flat portion may be made of the same material. Description of the Drawings

[0052] The accompanying drawings attached to this specification illustrate embodiments of the present disclosure and further describe aspects and features of the present invention in conjunction with the detailed description of the present disclosure. Therefore, the present disclosure should not be construed as limited to the drawings, in which: Figure 1 is a perspective view of a secondary battery according to various embodiments of the present disclosure; Figure 2 is Figure 1 a cross-sectional view of the secondary battery shown in Figure 3 is Figure 2 an enlarged cross-sectional view of part 3 in Figures 4 to 6 and is Figure 2 an enlarged cross-sectional view of part 3 in Detailed Description of the Embodiments

[0053] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0054] However, the embodiments of the present disclosure can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be thorough and complete and will fully convey aspects and features of the present disclosure to those skilled in the art.

[0055] It will be understood that when an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it can be directly on, directly connected to, or directly coupled to the other element or layer, or there can also be one or more intervening elements or layers. When an element or layer is referred to as being "directly on," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers. For example, when a first element is described as being "coupled" to or "connected" to a second element, the first element can be directly coupled to or directly connected to the second element, or the first element can be indirectly coupled to or indirectly connected to the second element via one or more intervening elements.

[0056] In the figures, for clarity of illustration, the dimensions of various elements, layers, etc. may be exaggerated. The same reference numerals denote the same elements. As used herein, the term "and / or" includes any combination and all combinations of one or more of the associated listed items. Additionally, when describing embodiments of the present disclosure, the use of "may" pertains to "one or more embodiments of the present disclosure". When expressions such as "at least one of..." and "any one of..." are used after a list of elements, they modify the entire list of elements and not individual elements in the list. For example, the expression "at least one of a, b, or c" indicates only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variants thereof. As used herein, the term "use" and its variants may be considered synonymous with the term "utilize" and its variants, respectively. As used herein, the terms "substantially", "about", and similar terms are used as approximate terms and not as terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by a person of ordinary skill in the art.

[0057] It will be understood that although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Thus, without departing from the teachings of the exemplary embodiments, the first element, first component, first region, first layer, or first part discussed below may be referred to as the second element, second component, second region, second layer, or second part.

[0058] For ease of description, spatial relative terms such as "under", "below", "lower", "above", "upper", etc. may be used herein to describe the relationship of one element or feature to another (other) element or feature as shown in the figures. It will be understood that, in addition to the orientation depicted in the figures, the spatial relative terms are also intended to encompass different orientations of the device during use or operation. For example, if the device in the figures is flipped, an element described as "under" or "below" other elements or features will subsequently be oriented "above" or "over" the said other elements or features. Thus, the term "under" can include both the upper and lower orientations simultaneously. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatial relative descriptors used herein should be interpreted accordingly.

[0059] The terms used herein are for the purpose of describing embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, unless the context clearly dictates otherwise, the singular forms "a" and "an" are also intended to include the plural forms. It will also be understood that when the terms "comprises," "comprising," and / or their variants are used in this specification, it is specified that the stated features, integers, steps, operations, elements, and / or components exist, but do not preclude the existence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0060] Figure 1 is a perspective view of a secondary battery according to various embodiments of the present disclosure, Figure 2 is Figure 1 a cross-sectional view of the secondary battery shown in Figure 2 is along Figure 1 a cross-sectional view of the secondary battery shown in

[0061] As Figure 1 and Figure 2 shown in, according to an embodiment of the present disclosure, the secondary battery 100 may include a can 110, an electrode assembly 120 accommodated in the can 110, a terminal portion 150 coupled to a terminal hole (e.g., a terminal opening) in one end of the can 110, and a cover plate 160 sealing an opening in the other end (e.g., the opposite end) of the can 110.

[0062] The can 110 may have a circular top surface portion 111 and a side surface portion 112 extending downward from an edge of the top surface portion 111 (e.g., from a periphery of the top surface portion 111) by a certain length (e.g., a predetermined length). The top surface portion 111 and the side surface portion 112 of the can 110 may be integral with each other (e.g., may be integrally formed with each other). In some embodiments, a portion (or region) between the top surface portion 111 and the side surface portion 112 may be curved to have a circular shape. Since the lower portion of the side surface portion 112 is open, the can 110 may have a cylindrical shape with an open lower end.

[0063] The circular top surface portion 111 may have a flat circular plate shape and may have a terminal hole (e.g., a terminal opening) 111a passing through its central portion. The terminal portion 150 may be coupled to the top surface portion 111 by being inserted into the terminal hole 111a. A portion of the terminal portion 150 may be exposed to the outside of the top surface portion 111 through the terminal hole 111a.

[0064] The upper end of the side surface portion 112 may be integrally formed with the top surface portion 111. The lower end of the side surface portion 112 may be open, and a cover plate 160 may be disposed at the open end (e.g., may be coupled to the side surface portion 112 at the open end). A curled portion (e.g., a curl) 113 may be provided on (e.g., may be formed on) the side surface portion 112 of the can 110 adjacent to the lower end. The curled portion 113 may be provided to be recessed inward from the side surface portion 112. The end spaced apart from the curled portion 113 may be bent toward the inside of the can 110 to provide (e.g., form) a crimping portion 114. The curled portion 113 may prevent the electrode assembly 200 from separating from the can 110. The cover plate 160 may be disposed (e.g., may be fixed or held) between the curled portion 113 and the crimping portion 114. The crimping portion 114 may fix the cover plate 160 to seal the can 110.

[0065] The can 110 may be made of steel, a steel alloy, aluminum, an aluminum alloy, or the like, but the material of the can 110 is not limited thereto.

[0066] During the process of manufacturing the secondary battery 100, the lower portion of the can 110 may be open. In some embodiments, during the process of manufacturing the secondary battery 100, the electrode assembly 120 may be inserted together with the electrolyte through the open lower portion of the can 110. In some embodiments, the electrolyte and the electrode assembly 120 may be inserted into the can 110 in a state where the open lower portion faces the upper side (e.g., upward with respect to the gravity plane). After the electrolyte and the electrode assembly 120 are inserted into the can 110, the cover plate 160 may be coupled to the open lower end of the can 110 to seal the inside of the can 110. In some embodiments, the electrolyte may allow lithium ions to move between the first electrode plate 121 and the second electrode plate 122 of the electrode assembly 120. The electrolyte may be a non-aqueous organic electrolyte that is a mixture of a lithium salt and a high-purity organic solvent. The electrolyte may be a polymer electrolyte or a solid electrolyte using (or including) a polymer, but the type of the electrolyte is not limited herein.

[0067] After the electrode assembly 120 is inserted through the open lower end of the can 110, a curled portion 113 may be provided (e.g., may be formed) in the can 110 to prevent the electrode assembly 120 from separating from the can 110.

[0068] As Figure 2 shown, the electrode assembly 120 may include a first electrode plate 121, a second electrode plate 122, and a separator 123. The first electrode plate 121 may be a positive electrode plate, and the second electrode plate 122 may be a negative electrode plate, but the reverse is also possible. Hereinafter, for ease of description, the first electrode plate 121 will be referred to as the positive electrode plate, and the second electrode plate 122 will be referred to as the negative electrode plate.

[0069] In the first electrode plate 121, at least one surface of a plate-shaped metal foil made of aluminum (Al) is coated with a positive electrode active material made of a transition metal oxide. In some embodiments, the first electrode plate 121 may have, at its upper end, a positive electrode uncoated portion that is an area of the metal foil where the positive electrode active material is not coated. The positive electrode uncoated portion may protrude toward the upper side of the electrode assembly 120 (or may protrude from the upper side or above of the electrode assembly). In some embodiments, the positive electrode uncoated portion of the first electrode plate 121 may protrude farther upward than the second electrode plate 122 and the separator 123 (e.g., may protrude upward beyond the second electrode plate 122 and the separator 123).

[0070] The second electrode plate 122 may be a plate-shaped metal foil made of copper (Cu) or nickel (Ni) and having at least one surface coated with a negative electrode active material such as graphite or carbon. In some embodiments, the second electrode plate 122 may have, at its lower end, a negative electrode uncoated portion that is an area of the metal foil where the negative electrode active material is not coated. The negative electrode uncoated portion may protrude toward the lower side of the electrode assembly 120 (or may protrude from the lower side or below of the electrode assembly 120). In some embodiments, the negative electrode uncoated portion of the second electrode plate 122 may protrude farther downward than the first electrode plate 121 and the separator 123 (e.g., may protrude downward beyond the first electrode plate 121 and the separator 123).

[0071] The separator 123 may be made of polyethylene (PE) or polypropylene (PP), but the present disclosure is not limited thereto. The separator 123 may be disposed between the first electrode plate 121 and the second electrode plate 122 to prevent a short circuit between the first electrode plate 121 and the second electrode plate 122, but allows lithium ions to move between the first electrode plate 121 and the second electrode plate 122.

[0072] After stacking the first electrode plate 121, the second electrode plate 122, and the separator 123, the electrode assembly 120 may be wound from the winding front end to have a substantially cylindrical shape. In some embodiments, in the electrode assembly 120, the positive electrode uncoated portion where the positive electrode active material is not coated may protrude upward from the first electrode plate 121, and the negative electrode uncoated portion where the negative electrode active material is not coated may protrude downward from the second electrode plate 122. In some embodiments, the electrode assembly 120 may be arranged (e.g., may be formed or constructed) such that the outermost positive electrode uncoated portion does not protrude upward, and the outermost negative electrode uncoated portion does not protrude downward. In some embodiments, the electrode assembly 120 may have a stepped portion where the outermost sides of each of the upper and lower portions are further recessed than other regions.

[0073] The first current collector plate 130 may be a circular metal plate having a shape corresponding to the top surface of the electrode assembly 120. The planar dimension of the first current collector plate 130 may be equal to or smaller than the dimension of the top surface of the electrode assembly 120. The first current collector plate 130 may be made of aluminum (Al). In a state where the bottom surface of the first current collector plate 130 is in contact with the top surface of the electrode assembly 120, the first current collector plate 130 may be fixed and electrically connected to the first electrode plate 121 exposed at (or from) the upper side of the electrode assembly 120 by welding. In a state where the top surface of the first current collector plate 130 is in contact with the bottom surface of the terminal portion 150, the first current collector plate 130 may be fixed and electrically connected to the terminal portion 150 by welding. The first current collector plate 130 may serve as a path for current flow between the first electrode plate 121 of the electrode assembly 120 and the terminal portion 150. The first current collector plate 130 may be welded to the electrode assembly 120, and may be accommodated in the can 110 and then welded to the terminal portion 150. The first current collector plate 130 may have a thickness smaller than the thickness of the lower body 151-2b of the terminal portion 150 (e.g., see Figure 3 ) to improve weldability.

[0074] The second current collector plate 140 may include a circular planar portion 141 corresponding to the bottom surface of the electrode assembly 120 and an extension portion 142 extending downward from the edge of the planar portion 141 (e.g., from the periphery of the planar portion 141). The top surface of the planar portion 141 may be in contact with the bottom surface of the electrode assembly 120. The top surface of the planar portion 141 may be fixed and electrically connected to the second electrode plate 122 exposed at the lower side of the electrode assembly 120 by welding in a state of being in contact with the bottom surface of the electrode assembly 120.

[0075] The extension part 142 can extend downward from the edge of the planar part 141. For example, a plurality of extension parts 142 can be provided, and the extension parts are spaced apart from each other along the edge of the planar part 141 (e.g., around the planar part 141). For example, the second current collector plate 140 can include four extension parts 142 symmetrically arranged with respect to each other about the planar part 141, but the present disclosure is not limited thereto. The extension part 142 can be bent to extend downward from the edge of the planar part 141. In some embodiments, the extension part 142 can contact the inner surface of the curled edge part 113. In some embodiments, the extension part 142 can be rounded or bent along the curled edge part 113 (e.g., can extend along and corresponding to the curled edge part 113). In some embodiments, the inner surface of the curled edge part 113 can be the inner surface of the can 110. The end of the extension part 142 can be disposed between the curled edge part 113 and the gasket 115. The extension part 142 can contact and be joined to the curled edge part 113 of the can 110. In some embodiments, the extension part 142 can be joined by welding in a state of contacting the inner surface of the curled edge part 113 of the can 110. The second current collector plate 140 can serve as a path for current flow between the second electrode plate 122 of the electrode assembly 120 and the can 110. In some embodiments, the can 110 can be (or can act as) a negative electrode terminal.

[0076] Figure 3 is Figure 2 an enlarged cross-sectional view of part 3 in; Figures 4 to 6 is according to other embodiments of the present disclosure Figure 2 an enlarged cross-sectional view of part 3 in. As Figures 3 to 6 shown in, the terminal part 150 can include a riveted terminal 151 and a plurality of insulators 152 for insulating the riveted terminal 151.

[0077] The riveting terminal 151 can be inserted into the terminal hole 111a in the top surface portion 111 of the can 110 and electrically connected to the first current collector plate 130. The riveting terminal 151 can be electrically connected to the first electrode plate 121 of the electrode assembly 120 through the first current collector plate 130. That is, the riveting terminal 151 can be (or can act as) the positive electrode terminal. The riveting terminal 151 and the can 110 can have different polarities. The riveting terminal 151 and each of the first current collector plate 130 and the first electrode plate 121 can be made of the same or similar materials. The diameter of the portion of the riveting terminal 151 exposed at the upper side of the can 110 and the diameter of the portion of the riveting terminal 151 disposed on the bottom surface (e.g., the bottom surface of the top surface portion 111) inside the can 110 can each be greater than the diameter of the portion of the riveting terminal 151 disposed in the terminal hole 111a. That is, the riveting terminal 151 can be a terminal coupled to the top surface portion 111 of the can 110 by a riveting method. The riveting terminal 151 can be inserted into the terminal hole 111a from the outside of the can 110 toward the inside of the can 110. In some embodiments, one end of the riveting terminal 151 can be disposed outside the can 110 and the other end can be disposed inside the can 110.

[0078] One end of the riveting terminal 151 can have a hollow disk shape, can be exposed at the upper side of the can 110, and can be referred to as the head 151-1. The other end of the riveting terminal 151 can have a hollow cylindrical shape and can be referred to as the body 151-2 extending from the head 151-1 toward the inside of the can 110. The cylindrical body 151-2 can be deformed into a substantially disk shape by being pressed by a mechanical device. The upper end of the body 151-2 of the riveting terminal 151 can be connected to the side surface of the head 151-1, and the body 151-2 and the head 151-1 can be integral with each other (e.g., can be integrally formed). The lower portion of the body 151-2 can be compressed and deformed by riveting (e.g., can be compression molded by riveting), and the terminal hole 111a can be sealed by pressing the insulator 152. In some embodiments, the body 151-2 can have a diameter that gradually increases from the terminal hole 111a toward the inside of the can 110. The body 151-2 can have an upper body 151-2a disposed in the terminal hole 111a of the can 110 and a lower body 151-2b disposed inside the can 110. The diameter (e.g., outer diameter) of the lower body 151-2b can be greater than the diameter (e.g., outer diameter) of the upper body 151-2a. That is, the lower body 151-2b can be superimposed on the can 110 in a plane.

[0079] Before the riveted terminal 151 is coupled, the insulator 152 can be inserted between the head 151-1 and the top surface portion 111 of the can 110 to insulate the can 110 from the riveted terminal 151. As the riveted terminal 151 is inserted into the terminal hole 111a, the head 151-1 can be compressed and deformed by a process such as pressing or spinning. In some embodiments, the riveted terminal 151 can be in close contact with the top surface portion 111 of the can 110.

[0080] That is, the insulator 152 for sealing and electrical insulation can be disposed between the terminal hole 111a and the terminal portion 150. The insulator 152 can block (or can prevent) contact between the terminal portion 150 and the can 110 to electrically isolate the terminal portion 150 from the can 110. The insulator 152 can seal the terminal hole 111a in the top surface portion 111 of the can 110. The insulator 152 can be made of a resin material such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or the like.

[0081] In some embodiments, the insulator 152 can include a first insulator 152a, a second insulator 152b, and a third insulator 152c. The first insulator 152a, the second insulator 152b, and the third insulator 152c can be used (or can be formed or constructed) without limitation as long as each of the insulators is made of an insulating material.

[0082] The first insulator 152a can be disposed between the outer end of the riveted terminal 151 and the top surface portion 111. For example, the first insulator 152a can have a hollow disk shape. The diameter of the first insulator 152a can be greater than the diameter of the outer end of the riveted terminal 151. The first insulator 152a can be interposed to block electrical contact at the region where the head 151-1 and the top surface portion 111 overlap in a plane. In some embodiments, the first insulator 152a can be disposed between the head 151-1 and the top surface portion 111 of the can 110 so as not to overlap with the second insulator 152b in a plane.

[0083] The second insulator 152b may have a shape surrounding the terminal hole 111a in the top surface portion 111 (e.g., surrounding the terminal hole 111a in the top surface portion 111 or extending around the periphery of the terminal hole 111a in the top surface portion 111). For example, the second insulator 152b may be shaped to surround the outer and inner surfaces of the top surface portion 111 centered on the terminal hole 111a and define the terminal hole 111a in cross-section. The second insulator 152b may extend between the body 151-2 and the top surface portion 111 of the can 110. In some embodiments, the upper end of the second insulator 152b may contact the first insulator 152a. In some embodiments, the second insulator 152b and the first insulator 152a may be disposed between the riveted terminal 151 and the can 110 to electrically insulate the riveted terminal 151 from the can 110 and seal the riveted terminal 151 and the can 110. In some embodiments, the second insulator 152b and the first insulator 152a may be provided as an integral insulator 152. The second insulator 152b may contact the top and bottom surfaces of the top surface portion 111 of the can 110. In some embodiments, the second insulator 152b may contact the third insulator 152c.

[0084] The third insulator 152c may have a hollow disc shape and may be disposed between the inner surface of the top surface portion 111 and the inner end of the riveted terminal 151. The third insulator 152c may be disposed to cover the inner surface of the top surface portion 111 of the can 110 and may have a planar size larger than the planar size of the first current collector plate 130. The third insulator 152c may be attached to the inner surface of the top surface portion 111 by coating or adhesion. In some embodiments, the inner surface of the top surface portion 111 may be the surface facing the top surface of the electrode assembly 120 and may be the bottom surface of the top surface portion 111. The third insulator 152c may prevent the top surface portion 111 of the can 110 and the first electrode plate 121 of the electrode assembly 120 from contacting each other. As in other embodiments, the third insulator 152c may be disposed to cover the inner surface of the top surface portion 111 and the curved portion between the top surface portion 111 and the side surface portion 112, or may be disposed to cover only the inner surface of the top surface portion 111.

[0085] In some embodiments, the riveting terminal 151 may have a welding groove 151-1a with a certain depth in the direction from the top surface of the head 151-1 towards the body 151-2. In some embodiments, the welding groove 151-1a may be defined to pass through the center of the head 151-1 in the downward direction from the upper side of the body 151-2. The height of the welding groove 151-1a may be less than the total height of the riveting terminal 151. In some embodiments, the riveting terminal 151 may have the welding groove 151-1a, and thus, the lower thickness of the body 151-2 of the riveting terminal 151 can be reduced. The lower thickness of the body 151-2 may be the thickness from the inner surface of the lower part of the welding groove 151-1a to the bottom surface of the body 151-2. The lower thickness of the body 151-2 can be reduced by the welding groove 151-1a, and thus, the riveting terminal 151 and the first current collector plate 130 can be welded from the outside of the can 110.

[0086] For example, the lower part of the body 151-2 may have a thickness in the range of about 0.5 mm to about 1.5 mm. In some embodiments, if the lower thickness of the body 151-2 is less than about 0.5 mm, the rigidity of the can 110 may not be maintained. In some embodiments, if the lower thickness of the body 151-2 is greater than about 1.5 mm, the welding between the riveting terminal 151 and the first current collector plate 130 at the outside of the can 110 may be relatively difficult.

[0087] In some embodiments, the upper inner diameter of the welding groove 151-1a may be greater than the lower inner diameter. In some embodiments, the lower inner diameter of the welding groove 151-1a may be less than the diameter of the terminal hole 111a. For example, the lower inner diameter of the welding groove 151-1a may be in the range of about 0.5 mm to about 2 mm. If the lower inner diameter of the welding groove 151-1a is less than about 0.5 mm, the welding with the first current collector plate 130 may not be easy due to insufficient welding area. In some embodiments, if the lower inner diameter of the welding groove 151-1a is greater than about 2 mm, the riveting may not be easy due to the reduced rigidity of the riveting terminal 151. In some embodiments, the upper inner diameter of the welding groove 151-1a may be in the range of about 2 mm to about 5 mm. If the upper inner diameter of the welding groove 151-1a is less than about 2 mm, it is not easy to ensure the welding area, and if the welding is performed outside the welding groove 151-1a, damage to the head 151-1 may occur. In some embodiments, if the upper inner diameter of the welding groove 151-1a is greater than about 5 mm, the riveting may not be easy due to the reduced rigidity of the riveting terminal 151.

[0088] In addition, the riveting terminal 151 may have a welding groove 151-1a. Thus, even when the riveting terminal 151 is welded to the first current collector plate 130 outside the riveting terminal 151, the weld bead can be disposed inside the welding groove 151-1a to prevent the weld bead from protruding from (or above) the riveting terminal 151. In some embodiments, the riveting terminal 151 may be joined by welding in a state where the flat bottom surface of the riveting terminal 151 contacts the top surface of the first current collector plate 130.

[0089] In some embodiments, the riveting terminal 151 may have a welding groove 151-1a to allow welding to the first current collector plate 130 outside the riveting terminal 151, thereby preventing welding foreign matters from being generated inside the can 110 and preventing the electrode assembly 120 from being damaged by welding heat.

[0090] In some embodiments, according to some embodiments, a terminal liquid injection hole (e.g., a terminal liquid injection opening) 151-2c through which an electrolyte is injected into the can 110 may be defined in the riveting terminal 151 of the terminal portion 150. In some embodiments, the terminal liquid injection hole 151-2c may be defined (e.g., may be formed or extend through) by the body 151-2 of the riveting terminal 151. The terminal liquid injection hole 151-2c may be defined to pass through (or extend) from the bottom surface of the welding groove 151-1a to the bottom surface of the body 151-2. For example, as Figure 3 shown, the terminal liquid injection hole 151-2c may be defined at the center of the bottom surface of the welding groove 151-1a to provide a stepped shape. The inner diameter of the terminal liquid injection hole 151-2c may be smaller than the lower inner diameter of the welding groove 151-1a. Thus, in some embodiments, the electrolyte may be injected through the terminal liquid injection hole 151-2c defined in the riveting terminal 151.

[0091] In some embodiments, a liquid injection hole (e.g., a liquid injection opening) 131 through which an electrolyte is injected may be defined in the first current collector plate 130. The liquid injection hole 131 may be defined to correspond to the position of the terminal liquid injection hole 151-2c in the riveting terminal 151. In some embodiments, the position of the liquid injection hole 131 may be defined to be the same as the position of the terminal liquid injection hole 151-2c. In some embodiments, the inner diameter of the terminal liquid injection hole 151-2c may be the same as the inner diameter of the liquid injection hole 131. However, the present disclosure is not limited thereto, and the inner diameters of the terminal liquid injection hole 151-2c and the liquid injection hole 131 may be different from each other.

[0092] In some embodiments, in a state where the top surface of the first current collector plate 130 is in contact with the bottom surface of the main body 151-2, the first current collector plate 130 can be welded from the outside of the riveting terminal 151 through the welding groove 151-1a. Therefore, a weld bead can be provided on the outer circumference of the upper part of the terminal liquid injection hole 151-2c within the welding groove 151-1a. In some embodiments, the weld bead can be provided along the upper circumference of the terminal liquid injection hole 151-2c.

[0093] As Figure 3 shown, the terminal portion 150 may further include a terminal flat portion 153 provided on the top surface of the riveting terminal 151. The terminal flat portion 153 may be provided to cover the top surface of the riveting terminal 151. The terminal flat portion 153 may be provided in a shape corresponding to the upper planar shape of the terminal portion 150, and in some embodiments, the terminal flat portion 153 may have a circular shape. The planar dimension of the terminal flat portion 153 may be less than or equal to the planar dimension of the head 151-1 of the riveting terminal 151. In some embodiments, a stepped portion may be provided along the circumference of the upper edge of the terminal flat portion 153. Therefore, in some embodiments, in a state where the top surface of the riveting terminal 151 is in contact with the bottom surface of the terminal flat portion 153, the riveting terminal 151 can be welded at the step formed at the edge of the terminal flat portion 153. In some embodiments, a welding area 153a may be provided on the stepped portion provided along the circumference of the terminal flat portion 153, and a weld bead may be formed at this stepped portion. In some embodiments, the diameter of the welding area 153a in the terminal flat portion 153 may be less than the outer diameter of the head 151-1 of the riveting terminal 151.

[0094] Furthermore, the terminal flat portion 153 has a protrusion 153b protruding in the direction of the welding groove 151-1a of the riveting terminal 151 (e.g., protruding toward the welding groove 151-1a of the riveting terminal 151) to be coupled to the welding groove 151-1a of the riveting terminal 151. The terminal flat portion 153 may be made of the same or similar material as each of the riveting terminal 151 and the first current collector plate 130. The protrusion 153b of the terminal flat portion 153 may have a tapered shape such that its outer diameter becomes smaller in the protruding direction. In some embodiments, the protrusion 153b may be provided (or formed) to correspond to the shape of the welding groove 151-1a.

[0095] In some embodiments, for example, as Figure 3 shown, the protrusion 153b may fill a partial area of the welding groove 151-1a. In some embodiments, for example, as Figure 4As shown, the protrusion 153b may have the same shape as the shape of the welding groove 151-1a and may be combined to be in close contact with the welding groove 151-1a (e.g., may completely fill the welding groove 151-1a).

[0096] In some embodiments, referring to Figure 5 and Figure 6 , the protrusion 153b may have an additional protrusion 153c protruding in the direction toward the terminal liquid injection hole 151-2c to be combined with the terminal liquid injection hole 151-2c. In some embodiments, the outer diameter of the additional protrusion 153c of the terminal flat portion 153 may be set to correspond to the inner diameter of the terminal liquid injection hole 151-2c. In some embodiments, the outer diameter of the additional protrusion 153c may be set to be the same as the inner diameter of the terminal liquid injection hole 151-2c to be in close contact with the terminal liquid injection hole 151-2c (e.g., completely fill the terminal liquid injection hole 151-2c) and be combined with the terminal liquid injection hole 151-2c.

[0097] In some embodiments, for example, as Figure 5 shown, the protrusion 153b may be set to have the same shape as the shape of the welding groove 151-1a and may be combined to be in close contact with the welding groove 151-1a. In other embodiments, for example, as Figure 6 shown, the protrusion 153b may be set to only partially fill the area of the welding groove 151-1a. If the terminal flat portion 153 includes the protrusion 153b and the additional protrusion 153c, the positions of the welding groove 151-1a and the terminal liquid injection hole 151-2c can be better controlled.

[0098] In some embodiments, the terminal liquid injection hole 151-2c may be defined in the terminal portion 150, the terminal portion 150 may be used as a liquid injection port, and the thickness of the terminal portion 150 may be adjusted to achieve external welding. In some embodiments, by additionally providing the terminal flat portion 153 on the upper part of the riveted terminal 151 of the terminal portion 150, the sealing force of the terminal liquid injection hole 151-2c can be improved.

[0099] The cover plate 160 may be a circular metal plate and may be combined to the lower end of the can 110. The bottom surface of the cover plate 160 may be exposed to the outside. The cover plate 160 may be combined to the lower end of the can 110 in a state where the gasket 115 is placed between the cover plate 160 and the lower end of the can 110 to prevent the cover plate 160 from being electrically connected to the lower end of the can 110. Since the cover plate 160 is not electrically connected to the positive electrode or the negative electrode of the electrode assembly 120, the cover plate 160 may not have a separate electrode polarity (e.g., may be electrically floating).

[0100] The cover plate 160 can be fixed in a state where the edge region of the cover plate 160 is disposed between the curled portion 113 and the crimped portion 114 of the can 110. In some embodiments, with the gasket 115 disposed on the lower portion of the curled portion 113 of the can 110, the cover plate 160 can be placed on the lower portion of the gasket 115. Thereafter, the crimped portion 114 of the can 110 can be bent inwardly toward the cover plate 160 to press the gasket 115 and bond the cover plate 160 to the can 110. The gasket 115 can be made of a resin material such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc. The gasket 115 can press the can 110 and the cover plate 160 to seal the gap between the can 110 and the cover plate 160, thereby preventing the cover plate 160 from separating from the can 110. The gasket 115 can have an upper portion disposed between the curled portion 113 and the cover plate 160 and a lower portion disposed between the crimped portion 114 and the cover plate 160. The lower end of the gasket 115 can protrude toward the center of the cover plate 160 (or protrude farther than the crimped portion 114).

[0101] The cover plate 160 can have a central region 161 corresponding to the lower portion of the second current collector plate 140 and an edge region 162 disposed between the curled portion 113 and the crimped portion 114 of the can 110 and bonded to the can 110. In some embodiments, the central region 161 of the cover plate 160 can be recessed toward the inside of the can 110 compared to the edge region 162. In some embodiments, the edge region 162 of the cover plate 160 can protrude outward in a direction away from the inside of the can 110 compared to the central region 161. In some embodiments, the cover plate 160 can have a connection region 163 connecting the central region 161 to the edge region 162 (or extending between the central region 161 and the edge region 162). The connection region 163 can be inclined due to a step portion between the central region 161 and the edge region 162. In some embodiments, curved portions can be provided between the connection region 163 and the central region 161 and between the connection region 163 and the edge region 162.

[0102] The cover plate 160 can be provided with an exhaust port 164 in the central region 161 that is configured to open (e.g., burst) at a reference (or set) pressure. The exhaust port 164 can have a thickness thinner than other regions of the cover plate 160. The exhaust port 164 can be a notch formed upward from the bottom surface of the cover plate 160.

[0103] If an excessive internal pressure occurs (or is generated) inside the can 110 of the secondary battery 100, the vent 164 will rupture (e.g., burst) to release the excessive internal pressure. The vent 164 of the cover plate 160 can be spaced apart from the center of the cover plate 160 and can be arranged in an annular shape on a plane. In other embodiments, the vent 164 can have at least one pattern with a straight or curved shape on a plane. The thickness of the vent 164 can be less than the thickness of other regions of the cover plate 160. The thickness of the vent 164 can be in the range of about 0.05 mm to about 0.35 mm. If the thickness of the vent 164 is less than about 0.05 mm, deformation or cracks will occur even if the internal pressure of the secondary battery 100 does not increase, and if the thickness exceeds about 0.35 mm, the vent 164 will not rupture (e.g., burst) and will not operate as a vent 164 even if the internal pressure of the secondary battery 100 increases to the reference pressure.

[0104] In a secondary battery, according to various embodiments of the present disclosure, the terminal and the current collector plate can be welded outside the can through a welding groove provided in the lower terminal to prevent the generation of welding impurities inside the housing and / or prevent the electrode assembly from being damaged by welding heat.

[0105] In a secondary battery, according to various embodiments of the present disclosure, since the current collector plate and the terminal are welded inside the welding groove of the terminal, a weld bead can be provided inside the welding groove to prevent the terminal from protruding due to an external (or protruding) weld bead.

[0106] Furthermore, in a secondary battery, according to various embodiments of the present disclosure, since the terminal liquid injection hole in the terminal passes through the terminal such that the electrolyte is injected through the terminal, an extrusion phenomenon in which the electrolyte moves and escapes between the gasket and the can due to the residual electrolyte in the crimped portion during molding can be prevented.

[0107] Furthermore, according to various embodiments of the present disclosure, the secondary battery can have an additional terminal at the upper portion of the terminal to seal the terminal liquid injection hole, and a protrusion can protrude in the direction of the terminal liquid injection hole to control the position of the additional terminal, thereby further improving the sealing force of the terminal liquid injection hole.

[0108] The above embodiments are merely some embodiments of the secondary battery according to the present disclosure. Therefore, the present disclosure is not limited to the foregoing embodiments. Those of ordinary skill in the art will also understand that various changes in form and detail can be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. A secondary battery, the secondary battery comprising: An electrode assembly including a first electrode plate, a separator, and a second electrode plate; A can that houses the electrode assembly, the lower end of the can being open and electrically connected to the second electrode plate; A first current collector plate located between the top surface of the electrode assembly and the can and electrically connected to the first electrode plate; And A terminal portion passing through the top surface of the can, the lower end of the terminal portion being electrically and mechanically joined to the top surface of the first current collector plate, Wherein a terminal liquid injection hole extends through the terminal portion, and an electrolyte is injected through the terminal liquid injection hole.

2. The secondary battery according to claim 1, wherein, The terminal portion includes: A riveted terminal joined to the top surface of the can; and An insulator located between the can and the riveted terminal to insulate the can and the riveted terminal from each other.

3. The secondary battery according to claim 2, wherein, The can has the top surface having a flat plate shape and a terminal hole, and a side surface extending downward from the edge of the top surface of the can, the terminal hole passing through the central portion of the top surface of the can, Wherein the riveted terminal is located in the terminal hole.

4. The secondary battery according to claim 3, wherein, The riveted terminal includes: A head located outside the top surface of the can; and A body inserted into the terminal hole and extending toward the inside of the can.

5. The secondary battery according to claim 4, wherein, The planar dimension of the head is larger than the planar dimension of the body.

6. The secondary battery according to claim 4, wherein, The body has: An upper body portion connected to the head and located within the terminal hole in the top surface of the can; and A lower body portion extending downward from the upper body portion and located inside the can.

7. The secondary battery according to claim 6, wherein, The lower body portion has an outer diameter larger than the outer diameter of the upper body portion.

8. The secondary battery according to claim 4, wherein, The terminal liquid injection hole is in the body of the riveted terminal.

9. The secondary battery according to claim 8, wherein, The first current collector plate has an injection hole into which the electrolyte is injected, and Wherein the injection hole in the first current collector plate corresponds to the position of the terminal hole in the riveted terminal.

10. The secondary battery according to claim 9, wherein, The terminal liquid injection hole has an inner diameter equal to the inner diameter of the injection hole in the first current collector plate.

11. The secondary battery according to claim 4, wherein, The riveted terminal has a welding groove having a depth in a downward direction from the top surface of the riveted terminal.

12. The secondary battery according to claim 11, wherein, In a state where the top surface of the first current collector plate is in contact with the bottom surface of the body, the first current collector plate is welded to the riveted terminal outside the riveted terminal through the welding groove such that the weld bead is located inside the welding groove.

13. The secondary battery according to claim 11, wherein The welding groove passes through the central portion of the head and extends downward from the upper portion of the body.

14. The secondary battery according to claim 11, wherein, The upper inner diameter of the welding groove is larger than the lower inner diameter of the welding groove.

15. The secondary battery according to claim 11, wherein, The terminal liquid injection hole extends from the bottom surface of the welding groove to the bottom surface of the body.

16. The secondary battery according to claim 15, wherein, The terminal liquid injection hole has an inner diameter smaller than the lower inner diameter of the welding groove.

17. The secondary battery according to claim 15, wherein, In a state where the top surface of the first current collector plate is in contact with the bottom surface of the body, the first current collector plate is welded outside the riveted terminal through the welding groove such that the weld bead is located in the welding groove.

18. The secondary battery according to claim 11, wherein, The terminal portion has a terminal flat portion on the top surface of the riveted terminal to cover the top surface of the riveted terminal.

19. The secondary battery according to claim 18, wherein, The terminal flat portion has a planar dimension smaller than the planar dimension of the head of the riveted terminal.

20. The secondary battery according to claim 18, wherein, The terminal flat portion has a stepped portion on the upper edge of the terminal flat portion.

21. The secondary battery according to claim 20, wherein In a state where the top surface of the riveted terminal is in contact with the bottom surface of the terminal flat portion, the riveted terminal is welded to the stepped portion on the upper edge of the terminal flat portion such that the weld bead is on the stepped portion along the circumference of the riveted terminal.

22. The secondary battery according to claim 21, wherein, The welding area of the terminal flat portion has a diameter smaller than the outer diameter of the head of the riveted terminal.

23. The secondary battery according to claim 18, wherein, The terminal flat portion has a protrusion protruding in a direction toward the welding groove in the riveted terminal and is coupled to the welding groove in the riveted terminal.

24. The secondary battery according to claim 23, wherein, The protrusion of the terminal flat portion has a tapered shape having an outer diameter that gradually decreases in the protruding direction.

25. The secondary battery according to claim 23, wherein, The protrusion of the terminal flat portion corresponds to the shape of the welding groove.

26. The secondary battery according to claim 23, wherein, The protrusion of the terminal flat portion partially fills the welding groove.

27. The secondary battery according to claim 23, wherein, The protrusion of the terminal flat portion has the same shape as the shape of the welding groove to be in close contact with the welding groove.

28. The secondary battery according to claim 23, wherein, The protrusion of the terminal flat portion includes an additional protrusion protruding in a direction toward the terminal liquid injection hole and is coupled to the terminal liquid injection hole.

29. The secondary battery according to claim 28, wherein, The additional protrusion of the terminal flat portion has an outer diameter corresponding to the inner diameter of the terminal liquid injection hole.

30. The secondary battery according to claim 28, wherein, The additional protrusion of the terminal flat portion has an outer diameter equal to the inner diameter of the terminal liquid injection hole to be in close contact with the terminal liquid injection hole.

31. The secondary battery according to claim 4, wherein, The insulator includes: a first insulator located between the outer end of the riveted terminal and the top surface of the can; a second insulator located at a side of the terminal hole in the top surface of the can and extending around the periphery of the terminal hole; and a third insulator located between the inner surface of the top surface of the can and the inner end of the riveted terminal.

32. The secondary battery according to claim 31, wherein, One end of the first insulator protrudes beyond the head.

33. The secondary battery according to claim 31, wherein, The first insulator has a planar dimension larger than the planar dimension of the head.

34. The secondary battery according to claim 31, wherein The third insulator has a planar dimension larger than the planar dimension of the first current collector plate.

35. The secondary battery according to claim 31, wherein, The third insulator covers the inner surface of the top surface of the can.

36. The secondary battery according to claim 1, wherein A positive electrode uncoated portion not coated with the positive electrode active material protrudes upward from the first electrode plate, and wherein a negative electrode uncoated portion not coated with the negative electrode active material protrudes downward from the second electrode plate.

37. The secondary battery according to claim 36, the secondary battery further comprising a second current collector plate, Among them, The can has the top surface having a flat plate shape and a terminal hole, and a side surface extending downward from an edge of the top surface of the can, the terminal hole passing through a central portion of the top surface of the can, and Wherein, the second current collector plate is adjacent to an end portion of the side surface and is electrically connected to the second electrode plate and the side surface.

38. The secondary battery according to claim 37, further comprising a cover plate, the cover plate being coupled to the side surface to seal a lower end of the can and being insulated from the side surface.

39. The secondary battery according to claim 38, wherein, The side surface has: a curled portion including an inwardly recessed portion of the side surface; and a crimped portion including an inwardly bent lower end of the side surface, wherein the cover plate is located between the curled portion and the crimped portion.

40. The secondary battery according to claim 39, further comprising a gasket, the gasket being located between the cover plate and the side surface.

41. The secondary battery according to claim 40, wherein, The second current collector plate is located between the curled portion and the gasket and is in contact with the curled portion.

42. The secondary battery according to claim 18, wherein, The riveted terminal, the first current collector plate, and the terminal flat portion are made of the same material.

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