Cylindrical secondary battery

Abstract

A cylindrical secondary battery includes: an electrode assembly including a first electrode plate, a separator, and a second electrode plate; a case accommodating the electrode assembly and electrically connected to the second electrode plate; a terminal electrically connected to the first electrode plate and coupled to the case via a first gasket; a cover plate configured to seal an upper end portion of the housing; the second gasket is arranged between the shell and the cover plate; a first current collector between a lower surface of the electrode assembly and the terminal; and a second current collector between an upper surface of the electrode assembly and the cap plate, and an edge region of the second current collector is between the case and the second gasket. An electrically conductive connection inducing portion is on at least one of the cap plate and the second current collector.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority and benefit of Korean Patent Application No. 10 - 2024 - 0009941, filed with the Korean Intellectual Property Office on January 23, 2024, the entire disclosure of which is incorporated herein by reference. Technical field

[0003] Aspects of embodiments of the present disclosure relate to a cylindrical secondary battery. Background art

[0004] Generally, a cylindrical secondary battery includes a cylindrical electrode assembly, a cylindrical case that houses the electrode assembly and an electrolyte, and a cover assembly that is coupled to an upper end opening of the case. The cover assembly seals the case and is electrically connected to the electrode assembly to electrically connect an external device to the electrode assembly.

[0005] A cylindrical secondary battery typically has a structure in which a case having a negative polarity and a cover assembly having a positive polarity are insulated from each other by a gasket. In a battery module including a plurality of cylindrical secondary batteries connected to each other, busbars need to be connected to upper and lower portions of the secondary batteries, thereby complicating the structure of the battery module and increasing manufacturing / assembly time.

[0006] In addition, since components of the cover assembly are insulated by a gasket, the cover plate generally has a non - polar structure. Accordingly, if the material of the cover plate is steel, nickel - plated steel, nickel, or copper, galvanic corrosion may occur due to long - term exposure to the electrolyte. Therefore, it is desirable to develop a structure that ensures electrical connection so that the cover plate has a negative (-) polarity structure.

[0007] The above information disclosed in the art used as the background of the present disclosure is only for enhancing the understanding of the background of the present disclosure and thus may include information that does not constitute related art. Summary of the invention

[0008] Embodiments of the present disclosure provide a cylindrical secondary battery including a cover plate having a negative polarity.

[0009] A cylindrical secondary battery according to an embodiment includes: an electrode assembly including a first electrode plate, a separator, and a second electrode plate; a cylindrical case accommodating the electrode assembly, having an open upper end portion, and electrically connected to the second electrode plate; a terminal passing through a lower surface of the cylindrical case and electrically connected to the first electrode plate, and coupled to the case via a first gasket; a cover plate configured to seal the upper end portion of the case; a second gasket between the case and the cover plate, and configured to perform sealing and insulation between the case and the cover plate; a first current collector between a lower surface of the electrode assembly and the terminal; and a second current collector located between an upper surface of the electrode assembly and the cover plate, and an edge region of the second current collector is between the case and the second gasket. A conductive connection initiation portion is provided on at least one of the cover plate and the second current collector.

[0010] The case may include: a crimping portion at an upper end of the case, and extending inwardly at a position above the cover plate to fix the cover plate; and a swaging portion recessed into the case at a position below the cover plate. An upper end of the second gasket may be between the cover plate and the crimping portion, and a lower end of the second gasket may be between the cover plate and the swaging portion.

[0011] The cover plate may include: a central region; a peripheral region between the crimping portion and the swaging portion; and a connection region connecting the central region and the peripheral region to each other, and formed recessedly in an outward direction of the case with respect to the central region and the peripheral region.

[0012] The case may include a trimming portion at an end of the crimping portion, the trimming portion being bent toward the cover plate and contacting the cover plate.

[0013] The trimming portion may protrude farther toward a center of the cover plate than a terminal end of the upper end of the second gasket.

[0014] The trimming portion may contact one side of the peripheral region of the cover plate.

[0015] The crimping portion may surround the second gasket to prevent the second gasket from being exposed to the outside.

[0016] The second gasket may have an annular shape having an open upper portion and a lower portion, and an upper end of the second gasket may be between an outer surface of an end of the cover plate and an inner surface of the crimping portion.

[0017] A terminal end of the upper end of the second gasket may protrude farther toward a center of the cover plate than the crimping portion.

[0018] The lower end portion of the first electrode plate may include a positive electrode uncoated portion on which no positive electrode active material is coated, and the upper end portion of the second electrode plate may include a negative electrode uncoated portion on which no negative electrode active material is coated.

[0019] The second current collector may have a circular plate shape corresponding to the upper surface of the electrode assembly, and may be in contact with and electrically connected to the second electrode plate exposed on the upper surface of the electrode assembly.

[0020] The second current collector may include: a flat portion in contact with the upper surface of the electrode assembly; and an extension portion extending upward from one side of the flat portion. The flat portion may include a circular first flat portion and a second flat portion extending outward from the first flat portion, and the second flat portion and the extension portion may be arranged along the circumference of the second current collector.

[0021] The extension portion of the second current collector may be between the second gasket and the pressing and winding portion.

[0022] The conductive connection initiation portion may include a first conductive connection initiation portion that is on one side of the second current collector and protrudes toward the cover plate, and the first conductive connection initiation portion may be in contact with one side of the lower surface of the cover plate.

[0023] The first conductive connection initiation portion may include at least two conductive connection initiation portions that are arranged along the circumference of the second current collector and are spaced apart from each other.

[0024] The first conductive connection initiation portion may protrude from the upper surface of the extension portion of the second current collector toward the cover plate.

[0025] The first conductive connection initiation portion may be an edge of the second current collector that protrudes toward the cover plate.

[0026] The first conductive connection initiation portion may be between the second flat portion and the extension portion of the second current collector.

[0027] The first conductive connection initiation portion may protrude upward and may gradually increase in width in the direction approaching the cover plate.

[0028] The first conductive connection initiation portion may have a bridge shape that is bent toward the cover plate.

[0029] The first conductive connection initiation portion may be on the extension portion of the second current collector.

[0030] The second flat portion of the second current collector may gradually increase in width in a direction from the center of the second current collector toward the edge of the second current collector.

[0031] The conductive connection initiation portion may include a second conductive connection initiation portion formed on one side of the cover plate and protruding toward the second current collector, and the second conductive connection initiation portion may contact one side of the upper surface of the second current collector.

[0032] The second conductive connection initiation portion may be on the lower surface of the connection area of the cover plate.

[0033] The second conductive connection initiation portion may have an annular shape on the lower surface of the cover plate and continuously extending along the circumference of the cover plate.

[0034] The second conductive connection initiation portion may include a plurality of protrusions, and the plurality of protrusions may be on the lower surface of the cover plate and spaced apart at a substantially regular interval along the circumference of the cover plate.

[0035] The conductive connection initiation portion may include: a first conductive connection initiation portion on one side of the second current collector and protruding toward the cover plate; and a second conductive connection initiation portion on one side of the cover plate and protruding toward the second current collector, and the first conductive connection initiation portion and the second conductive connection initiation portion may contact each other.

[0036] The first conductive connection initiation portion may include at least two conductive connection initiation portions arranged along the circumference of the second current collector and spaced apart from each other. The second conductive connection initiation portion may have an annular shape on the lower surface of the cover plate and continuously extend along the circumference of the cover plate, and the first conductive connection initiation portion may contact one side of the second conductive connection initiation portion.

[0037] The first conductive connection initiation portion may include at least two conductive connection initiation portions arranged along the circumference of the second current collector and spaced apart from each other. The second conductive connection initiation portion may include a plurality of protrusions, and the protrusions may be on the lower surface of the cover plate and spaced apart from each other at a substantially regular interval along the circumference of the cover plate. One side of the first conductive connection initiation portion and one side of the second conductive connection initiation portion may contact each other.

[0038] The position of the second conductive connection initiation portion and the position of the first conductive connection initiation portion may correspond to each other.

[0039] The width of the second conductive connection initiation portion and the width of the first conductive connection initiation portion may correspond to each other.

[0040] The second conductive connection initiation portion and the first conductive connection initiation portion may be misaligned with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The following drawings attached to this specification illustrate the disclosed embodiments and further describe aspects and features of the present disclosure together with the detailed description of the present disclosure. Therefore, the present disclosure should not be construed as being limited to the drawings:

[0042] Figure 1 is a perspective view showing a cylindrical secondary battery according to an embodiment;

[0043] Figure 2 is Figure 1 a cross-sectional view of the cylindrical secondary battery shown;

[0044] Figure 3 is an enlarged cross-sectional view of an upper end portion ( Figure 2 portion A in) of the cylindrical secondary battery according to an embodiment;

[0045] Figures 4A to 4D is a perspective view and a cross-sectional view showing the electrical contact between the cover plate and the negative electrode current collector due to the concavo-convex structure according to various embodiments;

[0046] Figures 5A to 5C is a perspective view and a cross-sectional view showing the electrical contact between the cover plate and the negative electrode current collector due to the bridge structure according to various embodiments; and

[0047] Figure 6A and Figure 6B is a perspective view and a cross-sectional view showing the electrical contact between the cover plate and the negative electrode current collector due to the protruding structure according to various embodiments. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] Hereinafter, embodiments will be described in detail with reference to the drawings. The embodiments are provided to more fully illustrate the present disclosure to those of ordinary skill in the art, and the following embodiments may be modified in various other forms, and the scope of the present disclosure is not limited to the following embodiments. The embodiments are provided to make the present disclosure more credible and complete and to fully convey the idea of the present disclosure to those skilled in the art.

[0049] In the following drawings, for convenience and clarity of description, the thickness or size of each layer is exaggerated, and the same reference numerals in the drawings refer to the same elements. As used herein, the term "and / or" includes any one of the listed items or any combination of one or more of them. As used herein, the term "connection" refers not only to a direct connection between member A and member B, but also to an indirect connection between member A and member B in the case where member C is interposed therebetween.

[0050] The terms used in the specification are intended to describe specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms may include the plural forms unless the context clearly dictates otherwise. As used herein, the terms "comprising" and / or "including" are intended to specify the presence of the stated figures, numbers, steps, operations, components, elements, and / or groups thereof, and do not preclude the presence or addition of one or more other figures, numbers, steps, operations, components, elements, and / or groups thereof.

[0051] Although terms such as first and second are used herein to describe various components, parts, regions, layers, and / or sections, these components, parts, regions, layers, and / or sections are not limited by these terms. These terms are only used to distinguish one component, one part, one region, one layer, or one section from another component, another part, another region, another layer, or another section. Thus, without departing from the teachings of the present disclosure, the first component, the first part, the first region, the first layer, or the first section described hereinafter may refer to the second component, the second part, the second region, the second layer, or the second section.

[0052] Spatial-related terms (such as "beneath", "below", "lower", "above", and "upper") may be used to facilitate an understanding of the relationship of one element or feature shown in the figures to another element or feature. Spatial-related terms are intended to facilitate an understanding of the present disclosure in various processes or usage states and are not intended to limit the present disclosure. For example, if an element or feature in the drawings is flipped, the element or feature described as "below" or "beneath" becomes "above" or "upper". Thus, "beneath" encompasses the concepts of "above" or "below".

[0053] Hereinafter, a cylindrical secondary battery according to an embodiment will be described in detail with reference to the drawings (for ease of description, in Figure 1 and Figure 2 the upper side is defined as the side facing the upward direction, and the lower side is defined as the side facing the downward direction).

[0054] Figure 1 is a perspective view showing a cylindrical secondary battery according to an embodiment, and Figure 2 is Figure 1 a cross-sectional view of the cylindrical secondary battery shown.

[0055] As Figure 1 and Figure 2 shown, the cylindrical secondary battery 100 according to an embodiment may include a case 110, an electrode assembly 120 accommodated in the case 110, a terminal 150 coupled to a terminal hole in one end of the case 110, and a cover plate 160 configured to seal an opening in the other end of the case 110.

[0056] The housing 110 may include a circular bottom surface portion 111 and side portions 112 extending a length in an upward direction from an edge (e.g., a perimeter) of the bottom surface portion 111. An upper end portion of the side portions 112 may be open. The bottom surface portion 111 and the side portions 112 of the housing 110 may be integrally formed.

[0057] The circular bottom surface portion 111 may be a flat circular plate and may have a terminal hole passing through its central portion. The terminal 150 may be inserted into the terminal hole to be coupled to the bottom surface portion 111. A first gasket 170 for sealing and electrical insulation may be between the terminal hole and the terminal 150. The first gasket 170 may block contact between the terminal 150 and the housing 110 to electrically isolate the terminal 150 and the housing 110 from each other. The terminal hole in the bottom surface portion 111 of the housing 110 may be sealed by the first gasket 170. The first gasket 170 may be formed of a resin material such as polyethylene (PE), polypropylene (PP), or polyethylene terephthalate (PET).

[0058] As described above, during the manufacturing process of the cylindrical secondary battery 100, since the upper end portion of the housing 110 is open, the electrode assembly 120 may be inserted into the housing 110 together with the electrolyte through the open upper end portion of the housing 110. After inserting the electrolyte and the electrode assembly 120 into the housing 110, the cover plate 160 may be coupled to the open upper end portion of the housing 110 to seal the interior of the housing 110. The electrolyte may be configured to allow lithium ions to move between the positive electrode plate and the negative electrode plate 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. Additionally, the electrolyte may be a polymer using a polymer electrolyte, or the electrolyte may be a solid electrolyte. However, the type of the electrolyte is not limited thereto.

[0059] The housing 110 may be or may include steel, a steel alloy, aluminum, an aluminum alloy, or the like. However, the material of the housing 110 is not limited thereto. The housing 110 may include a crimping portion 113 that is located below the cover plate 160 and is recessed inward to prevent the electrode assembly 120 from separating to the outside, and a crimping portion 114 that is located above the cover plate 160 and is bent inward. The crimping portion 113 may be formed in the housing 110 after inserting the electrode assembly 120 into the housing 110 through the open upper end portion of the housing 110, thereby preventing the electrode assembly 120 from separating from the housing 110.

[0060] When viewed from the outside of the case 110, the crimping portion 113 may be concave. The crimping portion 113 may be formed by squeezing the side portion 112 of the case 110 in a direction toward the inside of the electrode assembly 120. In one or more embodiments, the crimping portion 113 may protrude inward in an annular shape along the circumference of the side portion 112 of the case 110. The crimping portion 113 may be configured to press the second gasket 180 in a direction from the outside of the case 110 toward the inside of the case 110 (i.e., in a direction toward the winding center of the electrode assembly), thereby enhancing the sealing of the cylindrical secondary battery 100 through the second gasket 180. The crimping portion 113 may be formed at a portion of the case 110 that can contact the second gasket 180.

[0061] The case 110 may be or may include steel, a steel alloy, nickel-plated steel, a nickel-plated steel alloy, aluminum, an aluminum alloy, or the like. However, the material of the case 110 is not limited thereto. The crimping portion 113 may be on the inner circumferential surface of the side portion 112 and adjacent to the open upper end portion of the case 110, and the crimping portion 113 may protrude in a direction toward the winding center of the electrode assembly 120. In one embodiment, the cover plate 160 may be disposed on the crimping portion 113 and mainly supported by the crimping portion 113, and the second gasket 180, which will be described later, may contact the second current collector 140 and be subsidiarily supported by the second current collector 140, so that the cover plate 160 may be stably supported.

[0062] The electrode assembly 120 may include a first electrode plate 121, a second electrode plate 122, and a separator between the first electrode plate 121 and the second electrode plate 122. After stacking the first electrode plate 121, the second electrode plate 122, and the separator, the electrode assembly 120 may be wound from the winding front end into a substantially cylindrical shape. The first electrode plate 121 may be a positive electrode plate, and the second electrode plate 122 may be a negative electrode plate. In other embodiments, the first electrode plate 121 may be a negative electrode plate, and the second electrode plate 122 may be a positive electrode plate. Hereinafter, for ease of description, an embodiment in which the first electrode plate 121 is a positive electrode plate and the second electrode plate 122 is a negative electrode plate will be described.

[0063] The first electrode plate 121 may have a positive electrode active material (such as a transition metal oxide) coated on at least one surface of a plate-shaped metal foil made of aluminum (Al). The lower end portion of the first electrode plate 121 may include a positive electrode uncoated portion where the positive electrode active material is not coated. The positive electrode uncoated portion may protrude downward from the electrode assembly 120.

[0064] The second electrode plate 122 may have a negative electrode active material (such as graphite or carbon) coated on at least one surface of a plate-shaped metal foil made of copper (Cu) or nickel (Ni). An upper end portion of the second electrode plate 122 may include a negative electrode uncoated portion where the negative electrode active material is not coated. The negative electrode uncoated portion may protrude upward from the electrode assembly 120. The second electrode plate 122 may be electrically connected to the housing 110.

[0065] The separator may be made of polyethylene (PE) or polypropylene (PP). However, the embodiments are not limited thereto. The separator may be configured to prevent an electrical short circuit between the first electrode plate 121 and the second electrode plate 122 and to allow lithium ions to move therebetween.

[0066] The first current collector 130 may be a circular metal plate having a shape corresponding to the lower surface of the electrode assembly 120. A planar size of the first current collector 130 may be equal to or smaller than the size of the lower surface of the electrode assembly 120. The first current collector 130 may be or may include aluminum (Al). The first current collector 130 may be fixed and electrically connected to the first electrode plate 121 exposed below the electrode assembly 120 through one or more welding portions in a state where an upper surface of the first current collector 130 is in contact with the lower surface of the electrode assembly 120. The first current collector 30 may be fixed and electrically connected to the terminal 150 through one or more welding portions in a state where a lower surface of the first current collector 130 is in contact with an upper surface of the terminal 150. The first current collector 130 may be between the lower surface of the electrode assembly 120 and the terminal 150, and may be configured to serve as a channel for current flow between the first electrode plate 121 of the electrode assembly 120 and the terminal 150.

[0067] The second current collector 140 may have a circular plate shape corresponding to the upper surface of the electrode assembly 120, and may be in contact with and electrically connected to the second electrode plate 122 exposed above the upper surface of the electrode assembly 120.

[0068] The second current collector 140 may include a flat portion 141 in contact with the upper surface of the electrode assembly 120 and an extension portion 142 extending upward from one side of an edge of the flat portion 141. In one embodiment, the flat portion 141 may be circular. A lower surface of the flat portion 141 may be in contact with the upper surface of the electrode assembly 120. The flat portion 141 may be fixed and electrically connected to the second electrode plate 122 exposed above the electrode assembly 120 through welding in a state where the lower surface of the flat portion 141 is in contact with the upper surface of the electrode assembly 120.

[0069] The extension portion 142 can extend upward from one side of the edge of the flat portion 141. The extension portion 142 can contact and be coupled to the crimping portion 113 of the housing 110. In one embodiment, the extension portion 142 can be coupled to the crimping portion 113 of the housing 110 through one or more welding portions in a state of contacting the inner surface of the crimping portion 113 of the housing 110. A plurality of extension portions 142 can be spaced apart from each other along one side of the edge of the flat portion 141. In one embodiment, the flat portion 141 can include a circular first flat portion and a second flat portion extending outward from the circular first flat portion. In one embodiment, the second flat portion of the flat portion 141 and the extension portion 142 can be alternately arranged along the circumference of the second current collector 140.

[0070] The second current collector 140 can be located between the upper surface of the electrode assembly 120 and the cover plate 160, and one side of the extension portion 142 can be on the crimping portion 113 of the housing 110. The second current collector 140 can be configured to act as a channel for current flow between the second electrode plate 122 of the electrode assembly 120 and the housing 110. In one or more embodiments, the housing 110 can be a negative electrode terminal.

[0071] In one embodiment, the second current collector 140 can be formed into various other structures, and its detailed description will be provided hereinafter.

[0072] The terminal 150 can be inserted into a terminal hole formed in the bottom surface portion 111 of the housing 110 to be electrically connected to the first current collector 130. In one or more embodiments, the terminal 150 can be a positive electrode terminal. The terminal 150 and the housing 110 can have different polarities. The terminal 150 can be made of the same or similar material as the material of the first current collector 130 or the first electrode plate 121. The diameter of the portion of the terminal 150 exposed below (i.e., outside) the housing 110 and the diameter of the portion of the terminal 150 located in the housing 110 can be greater than the diameter of the portion of the terminal 150 located in the terminal hole.

[0073] The terminal 150 may include a head portion 151 and a fastening portion 152. The head portion 151 is the part exposed below (i.e., outside) the housing 110, and the fastening portion 152 is the part located in the housing 110 and facing the electrode assembly 120. The terminal 150 may be coupled to a terminal hole in the housing 110 in a direction from the outside to the inside. The head portion 151 may be located outside the housing 110. The fastening portion 152 may be compressed and deformed (compressed molded) by riveting, and thus may be compressed on the upper portion of the bottom surface portion 111 with the first gasket 170 between the terminal 150 and the bottom surface portion 111. The fastening portion 152 may have a diameter that gradually increases in a direction from the terminal hole toward the inside of the housing 110. The head portion 151 may be in close contact with the lower portion of the bottom surface portion 111 with the first gasket 170 between the head portion 151 and the bottom surface portion 111. In one or more embodiments, since the first gasket 170 is between the terminal 150 and the terminal hole, the first gasket 170 may electrically insulate the terminal 150 and the housing 110 from each other and may provide a seal therebetween. The terminal 150 may be electrically connected to the first electrode plate 121 of the electrode assembly 120 via the first current collector 130.

[0074] The cover plate 160 may be a circular metal plate and may be coupled to the upper end portion of the housing 110. The upper surface of the cover plate 160 may be exposed to the outside. The cover plate 160 may be coupled to the upper end portion of the housing 110 with the second gasket 180 between the cover plate 160 and the housing 110, and thus may prevent the cover plate 160 from being electrically connected to the housing 110. The cover plate 160 is not electrically connected to the positive or negative electrode of the electrode assembly 120 and thus may not have any separate electrode polarity. The cover plate 160 may be or may include aluminum, an aluminum alloy, or the like. The cover plate 160 may be a metal plate and may have a thickness in the range of about 0.7 mm to about 1.2 mm.

[0075] The cover plate 160 may include a central region 161, a peripheral region 162 between the crimping portion 114 and the crimping coil portion 113, and a connecting region 163 that interconnects the central region 161 and the peripheral region 162 and extends recessedly in an outward direction of the housing 110 with respect to the central region 161 and the peripheral region 162. The central region 161 may be a region within a radius from the center of the cover plate 160 and may be more recessed toward the electrode assembly 120 than the peripheral region 162 or may be coplanar with the peripheral region 162.

[0076] The peripheral region 162 of the cover plate 160 can be fixed between the crimping portion 113 and the crimping part 114 of the housing 110. In one or more embodiments, the cover plate 160 can be placed on the second gasket 180 in a state where the second gasket 180 is on the crimping portion 113 of the housing 110. Thereafter, the crimping part 114 of the housing 110 can be bent in the inward direction of the cover plate 160 to squeeze the second gasket 180, so that the cover plate 160 and the housing 110 are coupled to each other. The second gasket 180 can be configured to be squeezed and sealed between the housing 110 and the cover plate 160, and can prevent the cover plate 160 from separating from the housing 110.

[0077] As described above, the cover plate 160 can include a central region 161, a connecting region 163, and a peripheral region 162. The connecting region 163 extends outward from the central region 161, and the peripheral region 162 extends outward from the connecting region 163 and has an end portion between the crimping portion 113 and the crimping part 114 of the housing 110 to be coupled to the housing 110. The connecting region 163 can be located at a position higher than the central region 161 and the peripheral region 162. The peripheral region 162 can be located at a position higher than the central region 161 or at the same (or substantially the same) height as the central region 161.

[0078] In one or more embodiments, the cover plate 160 can include steps between the central region 161 and the connecting region 163 and between the connecting region 163 and the peripheral region 162. In one or more embodiments, the connecting portions between the central region 161 and the connecting region 163 and between the connecting region 163 and the peripheral region 162 can be inclined.

[0079] The cover plate 160 can be on the second gasket 180 in a state where the second gasket 180 is on the second current collector 140. The upper end of the second gasket 180 and the upper end of the housing 110 can be deformed together to surround the edge of the cover plate 160, so as to fix the cover plate 160 to the housing 110.

[0080] The cover plate 160 can include an exhaust portion 164, and thus can be configured to serve as an exhaust port in response to the generation of internal pressure. In one embodiment, the exhaust portion 164 can be a notch in the connecting region 163 of the cover plate 160, and the notch is configured to rupture in response to the generation of internal pressure. The notch can have an annular shape along the periphery of the cover plate 160. In one or more embodiments, the cover plate 160 can be configured to serve as a current interruption device (CID) that is deformed due to internal pressure to block the current path, or the cover plate 160 can be configured to serve as a fusing portion that includes a portion designed to melt due to high temperature to block the current path.

[0081] The cover plate 160 may have a generally circular plate shape and may not contact the second current collector 140 or the negative electrode tab. The cover plate 160 may be configured such that when viewed from the side, the plate surface of the connection region 163 is located at a position higher than the positions of the peripheral region 162 fixed to the second gasket 180 and the central region 161 at the central portion thereof. In one or more embodiments, the cover plate 160 may have a circular plate shape with its central portion protruding upward.

[0082] Figure 1 and Figure 2 Fig. shows a cylindrical secondary battery 100 in which the cover plate 160 and the second gasket 180 are accommodated in the case 110 to seal the case 110.

[0083] The upper portion of the case 110 may be bent toward the center of the case 110 by a crimping process to be deformed into a structure surrounding the upper portion of the second gasket 180 and the outer peripheral surface of the cover plate 160. In one or more embodiments, after the cover plate 160 and the second gasket 180 are accommodated in the case 110, the second gasket 80 and the cover plate 160 may be in close contact with each other in a state where the crimping portion 113 and the crimping portion 114 are formed. In one or more embodiments, the lower end portion of the second gasket 180 may be between the crimping portion 113 and the cover plate 160 and may be configured to block the contact between the crimping portion 113 and the cover plate 160. In one or more embodiments, the extending portion 142 of the second current collector 140 may be between the second gasket 180 and the crimping portion 113.

[0084] In one embodiment, the second gasket 180 may be between the case 110 and the cover plate 160 and cover the outer periphery of the cover plate 160. In one embodiment, the outer surface of the second gasket 180 may be in close contact with the crimping portion 113 and the crimping portion 114 of the case 110, and the inner surface of the second gasket 180 may be in close contact with the outer periphery of the cover plate 160. In one or more embodiments, the second gasket 180 may seal the case 110 and the cover plate 160 and insulate the case 110 and the cover plate 160. The second gasket 180 may be assembled with the cover plate 160 and then assembled with the case 110 to form and maintain a unitary seal. The side wall of the case 110 and the cover plate 160 may be sealed and insulated by the second gasket 180. In one embodiment, a separate upper insulating plate may not be provided, but a gasket integrated with the upper insulating plate may be used to insulate the electrode assembly 120 and the case 110 from each other (i.e., the gasket may serve as the upper insulating plate).

[0085] The second gasket 180 may be in the shape of a circular ring having an open upper portion and a lower portion. The upper end of the second gasket 180 may be between the outer surface of the end portion of the cover plate 160 and the inner surface of the crimping portion 114. In one or more embodiments, the end of the upper end of the second gasket 180 may protrude farther toward the center of the cover plate 160 than the crimping portion 114.

[0086] In one embodiment, the second gasket 180 may be between the housing 110 and the cover plate 160 and may electrically insulate the housing 110 and the cover plate 160 from each other. In one or more embodiments, the cover plate 160 may be a non-electrode portion. In the cylindrical secondary battery 100, since the terminal 150 is on one surface of the housing 110 rather than on the cover plate 160, a negative electrode and a positive electrode may be provided on this surface. However, if the material of the cover plate 160 is steel, nickel-plated steel, nickel, or copper, galvanic corrosion may occur due to long-term exposure to the electrolyte.

[0087] Accordingly, in one embodiment, a conductive connection initiation structure may be provided to achieve electrical contact between the cover plate 160 and the second current collector 140. In one embodiment, the cover plate 160 may be initiated to have a negative (-) polarity to prevent corrosion. In one embodiment, the conductive connection initiation structure may be in at least one of the cover plate 160 and the second current collector 140.

[0088] Hereinafter, a cylindrical secondary battery in which the conductive connection initiation structure is on the upper surface of the cover plate 160 will be described with reference to Figure 3 FIG.

[0089] Figure 3 is an enlarged cross-sectional view of an upper end portion ( Figure 2 portion A in) of a cylindrical secondary battery according to an embodiment.

[0090] In one embodiment, as Figure 3 shown, the upper end of the housing 110 may be configured to contact the cover plate 160. A trimming portion 115 bent toward the cover plate 160 may be formed at the end of the crimping portion 114 to contact the cover plate 160. The trimming portion 115 may protrude farther toward the center of the cover plate 160 than the end of the upper end of the second gasket 180. The trimming portion 115 may contact one side of the peripheral region 162 of the cover plate 160. The crimping portion 114 may surround the second gasket 180 such that the second gasket 80 is not exposed to the outside. In one embodiment, the portion of the upper surface of the cover plate 160 that contacts the trimming portion 115 may be referred to as a conductive connection initiation portion.

[0091] The second gasket 180 may include a sidewall portion 180a that is in close contact with the inner surface of the side portion 112 of the housing 110 and has an open upper portion and a lower portion, and a bottom portion 180b that extends inward perpendicular to (or substantially perpendicular to) the sidewall portion 118a. The bottom portion 180b may have a circular plate shape and may be parallel to (or substantially parallel to) the bottom surface portion 111 of the housing 110 and the cover plate 160. The sidewall portion 180a of the second gasket 180 may be deformed inward together with the housing 110 in a state of extending upward from the bottom portion 180b and surrounding the edge of the cover plate 160.

[0092] Reference will be made to Figure 3 The assembly process of the second gasket 180 of the cylindrical secondary battery 100 will be described in more detail. In one embodiment, the second gasket 180 may be disposed on the electrode assembly 120 in a state where the electrode assembly 120 is received in the housing 110. Thereafter, the cover plate 160 may be disposed on the second gasket 180. Subsequently, the upper end of the housing 110 may be deformed in a direction from the outside toward the inside (i.e., a direction toward the winding center of the electrode assembly). The second gasket 180 may be deformed together with the housing 110. Accordingly, the sidewall portion 180a of the second gasket 180 may be in close contact with the end portion of the cover plate 160, and the end portion of the cover plate 160 may be pressed and fixed by the sidewall portion 180a of the gasket 180 and the upper end of the side portion 112 of the housing 110. The cover plate 160 may be fixed by the housing 110 and the second gasket 180 is between the cover plate 160 and the housing 110.

[0093] In one embodiment, the upper end region of the sidewall portion 180a of the second gasket 180 may be located between the outer surface of the end portion of the cover plate 160 and the inner surface of the end region of the housing 110. This upper end region may be referred to as the folded sidewall portion 180a of the second gasket 180. In one embodiment, the trimming portion 115 of the housing 110 may protrude farther toward the winding center of the electrode assembly 120 than the upper end region of the sidewall portion 180a. In a state where the second gasket 180 is inserted into the housing 110, the height of the sidewall portion 180a of the second gasket 80 is lower than the height of the upper end of the side portion 112 of the housing 110. Since the covering length of the housing 110 is greater than the covering length of the second gasket 180, a conductive connection may be induced between the cover plate 160 and the housing 110.

[0094] In one embodiment, as described above, during the manufacture of the cylindrical secondary battery 100, when the end region of the side portion 112 of the case 110 is bent after the cover plate 160 is received (inserted) into the case 110, the upper end region of the side wall portion 180a of the second gasket 180 may also be bent, whereby the upper end region of the side wall portion 180a of the second gasket 180 may cover the end of the cover plate 160. Since the upper end region of the side wall portion 180a of the second gasket 180 is bent and extends inwardly, the sealing performance can be improved, and thus leakage of the electrolyte can be more reliably prevented or at least reduced.

[0095] The side wall portion 180a may be between the inner surface of the case 110 and the side surface and upper surface of the cover plate 160. The side wall portion 180a may be in close contact with the side wall of the inner surface of the case 110. The bottom portion 180b of the second gasket 180 may be between the inner surface of the case 110 and the lower surface of the cover plate 160, and may be in contact with the extension portion 142 (or the electrode tab). In one embodiment, although the side wall portion 180a and the bottom portion 180b are shown as being integrally formed with each other, the side wall portion 180a and the bottom portion 180b may be provided independently of each other. In one embodiment, since the second gasket 180 needs to be inserted into the case 110, the diameter of the bottom portion 180b may be smaller than the diameter of the case 110.

[0096] In one embodiment, the material of the second gasket 180 may be a polypropylene resin (PP) or a polybutylene terephthalate resin (PBT). However, the embodiments are not limited thereto. The material of the second gasket 180 may be a polyolefin resin, a polyester resin, or a polyether resin. In one or more embodiments, the second gasket 180 may be coated with tar. The tar is configured to continuously protect the coating and prevent the attachment of contaminants. In addition, the tar is configured to reduce the corrosion rate by suppressing the peeling of the coating, and thus durability can be maintained due to excellent mechanical strength and physical properties.

[0097] Hereinafter, embodiments of the first conductive connection initiation portions 143, 144, or 146 at the second current collector 140, embodiments of the second conductive connection initiation portion 165 at the cover plate 160, and embodiments in which both the first conductive connection initiation portions 143, 144, or 146 and the second conductive connection initiation portion 165 are provided will be described. The end of the upper end of the second gasket 180 may protrude farther toward the center of the cover plate 160 than the crimping portion 114. Figures 4A to 6B are perspective views and cross-sectional views showing the electrical contact between the cover plate and the negative electrode current collector due to the concavo-convex structure according to various embodiments.

[0098] Figures 4A to 4D are perspective views and cross-sectional views showing the electrical contact between the cover plate and the negative electrode current collector due to the concavo-convex structure according to various embodiments. Figures 5A to 5Care perspective views and cross-sectional views showing the electrical contact between the cover plate and the negative electrode current collector due to the bridge structure according to various embodiments. Figure 6A and Figure 6B are perspective views and cross-sectional views showing the electrical contact between the cover plate and the negative electrode current collector due to the protruding structure according to various embodiments.

[0099] Figure 4A is a perspective view showing the upper surface of the second current collector 140 including the first conductive connection initiation portion 143 and the lower surface of the cover plate 160 including the second conductive connection initiation portion 165 in a state before the second current collector 140 and the cover plate 160 are coupled to each other.

[0100] The first conductive connection initiation portion 143 may protrude from one side of the second current collector 140 toward the cover plate 160. In one embodiment, the first conductive connection initiation portion 143 may be on the extension portion 142 of the second current collector 140. The second conductive connection initiation portion 165 may be or include a protrusion extending toward the second current collector 140 on one side of the cover plate 160. In one embodiment, the second conductive connection initiation portion 165 may be on the connection region 163 of the cover plate 160. In an embodiment where the second current collector 140 and the cover plate 160 are coupled to each other, the protrusions of the first conductive connection initiation portion 143 and the second conductive connection initiation portion 165 may contact each other.

[0101] At least two first conductive connection initiation portions 143 may be arranged circumferentially along the plane of the second current collector 140 and spaced apart from each other. The second conductive connection initiation portion 165 may have an annular shape, where the protrusion is on the lower surface of the cover plate 160 and extends continuously along the circumference of the cover plate 160. The first conductive connection initiation portion 143 may contact one side of the protrusion of the second conductive connection initiation portion 165.

[0102] However, the embodiments are not limited thereto. The second conductive connection initiation part 165 may include a plurality of protrusions that are disposed on the lower surface of the cover plate 160 and are spaced apart from each other at regular (or substantially regular) intervals along the circumference of the cover plate 160. One side of the first conductive connection initiation part 143 and the protrusions of the second conductive connection initiation part 165 may be in contact with each other. In one embodiment, the protrusion positions of the protrusions of the second conductive connection initiation part 165 and the first conductive connection initiation part 143 may correspond to each other. In one or more embodiments, the width of the protrusions of the second conductive connection initiation part 165 and the protruding width of the first conductive connection initiation part 143 may correspond to each other (i.e., the widths may be the same or substantially the same). In other embodiments, the width of the protrusions of the second conductive connection initiation part 165 and the protruding width of the first conductive connection initiation part 143 may be different from each other. In one or more embodiments, one side of the protrusions of the second conductive connection initiation part 165 and one side of the first conductive connection initiation part 143 may be in contact with each other. In other embodiments, the protrusions of the second conductive connection initiation part 165 and the first conductive connection initiation part 143 may be coupled to each other in a state where the protrusion positions of the protrusions of the second conductive connection initiation part 165 and the first conductive connection initiation part 143 do not correspond to each other and are not aligned with each other (e.g., offset).

[0103] Figure 4B is a cross-sectional view for explaining a conductive connection initiation structure including the first conductive connection initiation part 143 having a concavo-convex structure and the second conductive connection initiation part 165. The first conductive connection initiation part 143 on the extension part 142 may be in contact with the second conductive connection initiation part 165. The end 142a of the extension part may be between the crimping part 113 and the second gasket 180.

[0104] Figure 4C is a cross-sectional view for explaining a conductive connection initiation structure including only the second conductive connection initiation part 165 (i.e., not including the first conductive connection initiation part 143). The second conductive connection initiation part 165 may be in contact with one side of the upper surface of the second current collector 140. In one embodiment, the second conductive connection initiation part 165 may be in contact with one side of the extension part 142 of the second current collector 140. The length by which the protrusions of the second conductive connection initiation part 165 protrude toward the second current collector 140 may be greater than the length by which the protrusions of the second conductive connection initiation part 165 protrude toward the second current collector 140 in an embodiment including both the first conductive connection initiation part 143 and the second conductive connection initiation part 165.

[0105] Figure 4DIt is a cross-sectional view for explaining a conductive connection initiation structure that only includes a first conductive connection initiation portion 143 having a concavo-convex structure (i.e., excluding the second conductive connection initiation portion 165). The first conductive connection initiation portion 143 may be in contact with one side of the lower surface of the connection region 163 of the cover plate 160. The length by which the first conductive connection initiation portion 143 protrudes toward the cover plate 160 may be greater than the length by which the first conductive connection initiation portion 143 protrudes toward the cover plate 160 in an embodiment including both the first conductive connection initiation portion 143 and the second conductive connection initiation portion 165.

[0106] Figure 5A It is a perspective view showing the upper surface of the second current collector 140 including the first conductive connection initiation portion 144 and the lower surface of the cover plate 160 in a state before the second current collector 140 and the cover plate 160 are coupled to each other. The first conductive connection initiation portion 144 has a shape in which the width gradually increases in the upward direction (e.g., fan-shaped).

[0107] The first conductive connection initiation portion 144 may protrude from one side of the second current collector 140 toward the cover plate 160. In one or more embodiments, the first conductive connection initiation portion 144 may be configured such that a part of the edge of the second current collector 140 protrudes toward the cover plate 160. In one embodiment, the first conductive connection initiation portion 144 may be the edge of the second current collector 140 that protrudes toward the cover plate 160. In an embodiment where the second current collector 140 and the cover plate 160 are coupled to each other, the first conductive connection initiation portion 144 and one side of the lower surface of the cover plate 160 may be in contact with each other.

[0108] The first conductive connection initiation portion 144 may be between the second flat portion of the flat portion 141 of the second current collector 140 and the extension portion 142. The first conductive connection initiation portion 144 may protrude upward from each side of the two sides in each extension portion 142. The width of the first conductive connection initiation portion 144 may gradually increase in the direction approaching the cover plate 160.

[0109] Figure 5B It is a cross-sectional view for explaining a conductive connection initiation structure including the first conductive connection initiation portion 144, and the first conductive connection initiation portion 144 is configured to protrude upward from one side of the edge of the flat portion 141. The first conductive connection initiation portion 144 separated from the extension portion 142 at one side of the edge of the flat portion 141 may be in contact with the lower surface of the connection region 163 of the cover plate 160. The end portion 142a of the extension portion may be between the crimping portion 113 and the second gasket 180.

[0110] Figure 5CIt is a cross-sectional view for explaining a conductive connection initiation structure including a first conductive connection initiation portion 144 and a second conductive connection initiation portion 165. The first conductive connection initiation portion 144 is configured to protrude upward from one side of the edge of the flat portion 141. The end of the first conductive connection initiation portion 144 may be in contact with the protruding end of the second conductive connection initiation portion 165. The protruding length of the first conductive connection initiation portion 144 may be less than the protruding length of the first conductive connection initiation portion 144 in an embodiment including only the first conductive connection initiation portion 144 (see Figure 4B ).

[0111] Figure 6A It is a perspective view showing the upper surface of the second current collector 140 including a first conductive connection initiation portion 146 (see Figure 6B ) and the lower surface of the cover plate 160 in a state before the second current collector 140 and the cover plate 160 are coupled to each other. The first conductive connection initiation portion 146 is configured to have the shape of a bridge with a bent portion protruding upward. In an embodiment where the second current collector 140 and the cover plate 160 are coupled to each other, one side of the first conductive connection initiation portion 146 and the lower surface of the cover plate 160 may be in contact with each other.

[0112] The first conductive connection initiation portion 146 may be on the extension portion 145 of the second current collector 140 and may have a bridge shape bent toward the cover plate 160. The second current collector 140 may include a plurality of first conductive connection initiation portions 146. As Figure 6A shown, the extension portion 145 may extend from one side of the flat portion 141 and may protrude upward. The end 145a of the extension portion may have an annular shape (i.e., a ring shape) continuously extending along the circumference of the second current collector 140. The second flat portion of the flat portion 141 of the second current collector 140 may gradually increase in width in a direction from the center of the second current collector 140 toward its edge. The second flat portion of the flat portion 141 may be spaced apart from the extension portion 145, and the extension portion 145 may be between adjacent second flat portions of the flat portion 141. The second flat portion of the flat portion 141 and the extension portion 145 may extend radially outward with respect to the center of the second current collector 140 and may be alternately arranged in the circumferential direction. The first conductive connection initiation portion 146 may be the highest protruding portion in the bridge-shaped extension portion 145. The first conductive connection initiation portion 146 may be the portion of the extension portion 145 that contacts the cover plate 160.

[0113] Figure 6BIt is a cross-sectional view of a conductive connection initiation structure for explaining a first conductive connection initiation portion 146 that protrudes from the extension portion 145 and bends toward the cover plate 160. The first conductive connection initiation portion 146 can contact one side of the cover plate 160. In one or more embodiments, the first conductive connection initiation portion 146 can contact the lower surface of the central region 161 of the cover plate 160. The end 145a of the extension portion can be between the crimping portion 113 and the second gasket 180.

[0114] In other embodiments, the second conductive connection initiation portion 165 can be in a raised shape on the cover plate 160 or can include a protrusion on the cover plate 160, and the protrusion of the second conductive connection initiation portion 165 and the bridge-shaped first conductive connection initiation portion 146 can contact each other. The second conductive connection initiation portion 165 can be on the central region 161, and the protrusion protruding from the central region 161 and the first conductive connection initiation portion 146 can contact each other. However, the embodiments are not limited thereto. The protrusion of the second conductive connection initiation portion 165 can be on the connection region 163, and the protrusion of the connection region 163 and the first conductive connection initiation portion 146 can contact each other.

[0115] As is apparent from the above description, according to the embodiment, in the case where the cover plate is insulated from the housing having a negative polarity through a gasket, a structure capable of initiating the cover plate to have a negative polarity can be adopted, thereby preventing galvanic corrosion caused by the long-term exposure of the cover plate to the electrolyte.

[0116] According to the embodiment, the conductive connection can be initiated by reducing the total height of the gasket such that the trimmed portion of the can and the cover plate contact each other after crimping or such that the cover plate and the negative electrode current collector are in electrical contact with each other, thereby preventing corrosion of the cover plate and improving the product quality.

[0117] The above embodiments are merely examples, and thus, the present disclosure is not limited to the foregoing embodiments, and those of ordinary skill in the art will understand that various changes in form and details can be made therein without departing from the spirit and scope of the present disclosure defined by the claims.

Claims

1. A cylindrical secondary battery, comprising: An electrode assembly, including a first electrode plate, a separator, and a second electrode plate; A cylindrical case, accommodating the electrode assembly, the cylindrical case including an open upper end portion, and the cylindrical case being electrically connected to the second electrode plate; A terminal, passing through the lower surface of the cylindrical case and electrically connected to the first electrode plate, and being coupled to the cylindrical case via a first gasket; A cover plate, configured to seal the open upper end portion of the cylindrical case; A second gasket, between the cylindrical case and the cover plate, the second gasket sealing and insulating between the cylindrical case and the cover plate; A first current collector, between the lower surface of the electrode assembly and the terminal; And A second current collector, between the upper surface of the electrode assembly and the cover plate, an edge region of the second current collector being between the cylindrical case and the second gasket, Wherein a conductive connection initiation portion is on at least one of the cover plate and the second current collector.

2. The cylindrical secondary battery according to claim 1, wherein the cylindrical case includes: A crimping portion, at the upper end of the cylindrical case, extending inwardly at a position above the cover plate, the crimping portion being configured to fix the cover plate; And A crimping and rolling portion, recessed into the cylindrical case at a position below the cover plate, and Wherein an upper end of the second gasket is between the cover plate and the crimping portion, and a lower end of the second gasket is between the cover plate and the crimping and rolling portion.

3. The cylindrical secondary battery according to claim 2, wherein the cover plate includes: A central region; A peripheral region, between the crimping portion and the crimping and rolling portion; And A connecting region, connecting the central region and the peripheral region to each other, the connecting region being concave in an outward direction of the cylindrical case with respect to the central region and the peripheral region.

4. The cylindrical secondary battery according to claim 3, wherein the cylindrical case includes a trimming portion at an end of the crimping portion, the trimming portion being bent toward the cover plate and contacting the cover plate.

5. The cylindrical secondary battery according to claim 4, wherein the trimming portion protrudes farther toward the center of the cover plate than an end of the upper end of the second gasket.

6. The cylindrical secondary battery according to claim 5, wherein the trimming portion contacts one side of the peripheral region of the cover plate.

7. The cylindrical secondary battery according to claim 2 or 3, wherein the crimping portion surrounds the second gasket, the crimping portion being configured to prevent the second gasket from being exposed to the outside.

8. The cylindrical secondary battery according to claim 3, wherein the second gasket has an annular shape, the annular shape having an open upper portion and a lower portion, and Wherein the upper end of the second gasket is between an outer surface of an end of the cover plate and an inner surface of the crimping portion.

9. The cylindrical secondary battery according to claim 3, wherein an end of an upper end of the second gasket protrudes further toward a center of the cover plate than the crimping portion.

10. The cylindrical secondary battery according to claim 9, wherein: a lower end portion of the first electrode plate includes a positive electrode uncoated portion on which no positive electrode active material is coated, and an upper end portion of the second electrode plate includes a negative electrode uncoated portion on which no negative electrode active material is coated.

11. The cylindrical secondary battery according to claim 10, wherein the second current collector has a circular plate shape corresponding to an upper surface of the electrode assembly, and wherein the second current collector contacts and is electrically connected to the second electrode plate exposed on the upper surface of the electrode assembly.

12. The cylindrical secondary battery according to claim 11, wherein the second current collector includes: a flat portion that contacts the upper surface of the electrode assembly; and an extension portion that extends upward from one side of the flat portion, and wherein the flat portion includes a circular first flat portion and a second flat portion that extends outward from the first flat portion, and the second flat portion and the extension portion are arranged along a circumference of the second current collector.

13. The cylindrical secondary battery according to claim 12, wherein the extension portion of the second current collector is between the second gasket and the crimping portion.

14. The cylindrical secondary battery according to claim 13, wherein the conductive connection initiation portion includes a first conductive connection initiation portion formed on one side of the second current collector and protruding toward the cover plate, and wherein the first conductive connection initiation portion contacts one side of a lower surface of the cover plate.

15. The cylindrical secondary battery according to claim 14, wherein the first conductive connection initiation portion includes at least two conductive connection initiation portions arranged along the circumference of the second current collector and spaced apart from each other.

16. The cylindrical secondary battery according to claim 15, wherein the first conductive connection initiation portion protrudes from an upper surface of the extension portion of the second current collector toward the cover plate.

17. The cylindrical secondary battery according to claim 15, wherein the first conductive connection initiation portion is an edge of the second current collector protruding toward the cover plate.

18. The cylindrical secondary battery according to claim 17, wherein the first conductive connection initiation portion is between the second flat portion and the extension portion of the second current collector.

19. The cylindrical secondary battery according to claim 18, wherein the first conductive connection initiation portion protrudes upward and gradually increases in width in a direction approaching the cover plate.

20. The cylindrical secondary battery according to claim 15, wherein the first conductive connection initiation portion has a bridge shape bent toward the cover plate.

21. The cylindrical secondary battery according to claim 20, wherein the first conductive connection initiation portion is on the extended portion of the second current collector.

22. The cylindrical secondary battery according to claim 20, wherein the second flat portion of the second current collector gradually increases in width in a direction from the center of the second current collector toward the edge of the second current collector.

23. The cylindrical secondary battery according to claim 9, wherein the conductive connection initiation portion includes a second conductive connection initiation portion that is on one side of the cover plate and protrudes toward the second current collector, and wherein the second conductive connection initiation portion contacts one side of the upper surface of the second current collector.

24. The cylindrical secondary battery according to claim 23, wherein the second conductive connection initiation portion is on the lower surface of the connection region of the cover plate.

25. The cylindrical secondary battery according to claim 23, wherein the second conductive connection initiation portion has an annular shape that is on the lower surface of the cover plate and continuously extends along the circumference of the cover plate.

26. The cylindrical secondary battery according to claim 23, wherein the second conductive connection initiation portion includes a plurality of protrusions, and wherein the plurality of protrusions are on the lower surface of the cover plate and are spaced apart from each other at regular intervals along the circumference of the cover plate.

27. The cylindrical secondary battery according to claim 9, wherein the conductive connection initiation portion includes: a first conductive connection initiation portion that is on one side of the second current collector and protrudes toward the cover plate; and a second conductive connection initiation portion that is formed on one side of the cover plate and protrudes toward the second current collector, and wherein the first conductive connection initiation portion and the second conductive connection initiation portion contact each other.

28. The cylindrical secondary battery according to claim 27, wherein the first conductive connection initiation portion includes at least two conductive connection initiation portions that are arranged along the circumference of the second current collector and are spaced apart from each other, wherein the second conductive connection initiation portion has an annular shape that continuously extends on the lower surface of the cover plate and extends along the circumference of the cover plate, and wherein the first conductive connection initiation portion contacts the second conductive connection initiation portion.

29. The cylindrical secondary battery according to claim 27, wherein the first conductive connection initiation portion includes at least two conductive connection initiation portions that are arranged along the circumference of the second current collector and are spaced apart from each other, wherein the second conductive connection initiation portion includes a plurality of protrusions, and wherein the plurality of protrusions are on the lower surface of the cover plate and are spaced apart from each other at regular intervals along the circumference of the cover plate, and wherein one side of the first conductive connection initiation portion and one side of the protrusions of the second conductive connection initiation portion contact each other.

30. The cylindrical secondary battery according to claim 29, wherein the positions of the second conductive connection initiation portion and the first conductive connection initiation portion correspond to each other.

31. The cylindrical secondary battery according to claim 29, wherein the width of the second conductive connection initiation portion corresponds to the width of the first conductive connection initiation portion.

32. The cylindrical secondary battery according to claim 29, wherein the second conductive connection initiation portion and the first conductive connection initiation portion are misaligned with each other.

Images