Cylindrical secondary battery

Abstract

A cylindrical secondary battery includes: an electrode assembly; a can in which the electrode assembly is accommodated, and including an upper surface portion at one end and formed with a terminal hole, and a cylindrical side portion extending downward from the upper surface portion; a terminal portion coupled to the terminal hole and electrically connected to the electrode assembly; a cover plate coupled to an end portion of the side portion; and an anti-corrosion material portion at a coupling portion of the side portion and the cover plate.

Description

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0175375 filed in the Korean Intellectual Property Office on December 6, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0002] Aspects of some embodiments of the present disclosure relate to a cylindrical secondary battery having a corrosion-resistant structure. Background Art

[0003] Recently, consumer demand for secondary batteries having a form in which both a positive electrode terminal and a negative electrode terminal are located on one side of the secondary battery is increasing. This type of secondary battery may have an advantage that an electrical connection structure with the outside is relatively simple.

[0004] In the above-mentioned secondary battery, one side of the cylindrical can or housing may be open, and the electrode assembly may be contained therein together with the electrolyte. The cap assembly may be connected to the open side of the can. In the case of a can, when a cut surface such as the open side is exposed to air for a long time, corrosion may occur, and thus rust may occur. Alternatively, due to the influence of the electrolyte, corrosion may occur at the connection portion (welding portion) between the cap assembly and the can.

[0005] Corrosion and rust may cause functional degradation of the secondary battery and thus may be desired to be prevented.

[0006] The above information disclosed in this background section is only for enhancement of understanding of the background technology and therefore the information discussed in this background section does not necessarily constitute prior art. Summary of the invention

[0007] Aspects of some embodiments of the present disclosure include a cylindrical secondary battery having an anti-corrosion structure.

[0008] According to some embodiments of the present disclosure, a cylindrical secondary battery includes: an electrode assembly; a can in which the electrode assembly is accommodated and includes an upper surface portion at one end and formed with a terminal hole and a cylindrical side portion extending downward from the upper surface portion; a terminal portion connected to the terminal hole to be electrically connected to the electrode assembly; a cover plate connected to an end portion of the side portion; and an anti-corrosion material portion or device provided at a connection portion between the side portion and the cover plate.

[0009] According to some embodiments, the side portion may include a curling portion concavely formed above the upper surface of the cover plate and a crimping portion spaced apart from the curling portion and having an end portion formed to be bent inwardly, and the cover plate may be between the curling portion and the crimping portion.

[0010] According to some embodiments, the cylindrical secondary battery may further include a gasket interposed between the cap plate and the side portion.

[0011] According to some embodiments, the anti-corrosion material portion may be provided to cover the end portion of the crimping portion.

[0012] According to some embodiments, the anti-corrosion material portion may be provided to cover the end portion of the crimping portion and the end portion of the gasket.

[0013] According to some embodiments, the anti-corrosion material portion may be provided to cover the end portion of the crimping portion, the end portion of the gasket, and a portion of the cover plate.

[0014] According to some embodiments, the cover plate may be welded to the side portions.

[0015] According to some embodiments, the anti-corrosion material portion may be provided to cover the end portion of the side portion.

[0016] According to some embodiments, the anti-corrosion material portion may be provided to cover a welded portion of the end portion of the side portion and the cover plate.

[0017] According to some embodiments, the anti-corrosion material portion may be an anti-corrosion liquid.

[0018] According to some embodiments, the cylindrical secondary battery may further include a protrusion or a rib formed to protrude from an outer end portion of the side portion and at least one surface of a side of the cap plate adjacent to the welding portion.

[0019] According to some embodiments, the protrusion or the rib may have a height lower than a weld bead formed in the welding portion of the cover plate.

[0020] According to some embodiments, the protrusion or the rib may have a circular ring shape.

[0021] According to some embodiments, the cover plate may further include a groove concavely formed from a surface of the cover plate adjacent to the welding portion.

[0022] In addition, according to some embodiments of the present disclosure, a cylindrical secondary battery includes: an electrode assembly; a can, in which the electrode assembly is accommodated and includes an upper surface portion at one end and formed with a terminal hole and a cylindrical side portion extending downward from the upper surface portion; a terminal portion, connected to the terminal hole to be electrically connected to the electrode assembly; a cover plate, connected to an end portion of the side portion and insulated from the can; and an anti-corrosion material portion, provided at a connecting portion between the terminal hole and the terminal portion.

[0023] According to some embodiments, the anti-corrosion material portion may be provided to cover a portion of a cut surface of the terminal hole and a portion of the upper surface portion adjacent to the terminal hole.

[0024] According to some embodiments, the anti-corrosion material portion may be an anti-corrosion liquid.

[0025] According to some embodiments, the cylindrical secondary battery may further include a coupling groove and a coupling protrusion formed by forging adjacent to the terminal hole.

[0026] According to some embodiments, the coupling groove may be formed concavely from the surface of the upper surface portion, the depth of the coupling groove may be smaller than the thickness of the upper surface portion, and the coupling protrusion may be formed adjacent to the coupling groove and face the interior of the tank.

[0027] According to some embodiments, the terminal portion may include a rivet terminal inserted into the terminal hole to be electrically connected to the electrode assembly and at least one insulator interposed between the rivet terminal and the upper surface portion of the can to insulate the rivet terminal from the upper surface portion of the can. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a perspective view of a cylindrical secondary battery according to some embodiments.

[0029] Figure 2 is based on Figure 1 Cross-sectional view of a cylindrical secondary battery.

[0030] Figure 3 is based on Figure 1 An enlarged cross-sectional view of a portion of a tank.

[0031] Figure 4 It is an example based on Figure 3 A cross-sectional view of the tank and insulator.

[0032] Figure 5 is a schematic diagram briefly illustrating an anti-corrosion portion according to some embodiments of the present disclosure.

[0033] Figure 6 and Figure 7 is a schematic diagram briefly illustrating an anti-corrosion portion according to some embodiments of the present disclosure.

[0034] Figure 8 is a schematic diagram briefly illustrating an example of an anti-corrosion portion according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0035] The aspects of some embodiments of the present disclosure are provided to more fully describe the present disclosure to those skilled in the art, and the following embodiments may be modified into various other forms, and the scope of the present disclosure is not limited to the following embodiments. On the contrary, these embodiments are provided to make the present disclosure more meaningful and more comprehensive and to fully convey the spirit of the present disclosure to those skilled in the art.

[0036] In addition, in the accompanying drawings, for the convenience and clarity of description, the size (e.g., thickness) of each layer is magnified, and the same reference numerals in the drawings indicate the same elements. As used in this specification, the term "and / or" includes any one and all combinations of one or more of the listed items. In addition, the meaning of "connection" in this specification refers not only to the case where component A and component B are directly connected, but also to the case where component C is between component A and component B to indirectly connect component A and component B.

[0037] The terms used in this specification are used to describe specific embodiments and are not intended to limit the present disclosure. As used in this specification, singular forms may include plural forms unless the context clearly states otherwise. In addition, when used in this specification, "including" and / or "comprising" specify the existence of the features, quantity, step, operation, member, element and / or their groups mentioned, and do not exclude the existence or addition of one or more other features, quantity, step, operation, member, element and / or their groups.

[0038] Although the terms "first", "second", etc. are used in this specification to describe various components, parts, regions, layers and / or parts, it is clear that these components, parts, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one component, component, region, layer or part from another component, component, region, layer or part. Accordingly, without departing from the teachings of the present disclosure, a first component, component, region, layer or part to be described later may refer to a second component, component, region, layer or part.

[0039] In order to easily understand the relationship between one element or feature shown in the figure and another element or feature, spatially related terms such as "under", "below", "down", "above" and "up" are used. These spatially related terms are provided to easily understand the present disclosure according to various process states or use states of the present disclosure, and are not intended to limit the present disclosure. For example, when an element or feature in the figure is turned over, the element described as "under" or "below" becomes "up" or "above". Accordingly, "below" is a concept that includes "above" and "below".

[0040] Here, a cylindrical secondary battery and a method for manufacturing the same according to some embodiments of the present disclosure will be described with reference to the accompanying drawings. Figure 1 and Figure 2 The cylindrical secondary battery is described with the upper side defined as the upper side and the lower side defined as the lower side.

[0041] Figure 1 is a perspective view of a cylindrical secondary battery according to some embodiments. Figure 2 is based on Figure 1 Cross-sectional view of a cylindrical secondary battery. Figure 3 is based on Figure 1 An enlarged cross-sectional view of a portion of a tank. Figure 4 It is an example based on Figure 3 A cross-sectional view of the tank and insulator.

[0042] like Figure 1 and Figure 2 As shown, a cylindrical secondary battery 10 according to some embodiments of the present disclosure may include a cylindrical can (or cylindrical shell) 100, an electrode assembly 200 accommodated, inserted or encapsulated in the can 100, a first electrode current collecting plate 300 and a second electrode current collecting plate 400, a terminal portion 500 provided on one side of the can 100, and a cover assembly 600 provided on the other side of the can 100.

[0043] like Figure 1 and Figure 2 As shown, the can 100 may include a circular upper surface portion 110 at one end and a cylindrical side portion 130 extending downward from the upper surface portion 110. Since the lower portion of the side portion 130 is open, the can 100 has a cylindrical shape with an open lower end.

[0044] like Figure 3 and Figure 4 As shown, a terminal hole 110a may be formed through the center of the upper surface part 110. A portion of the terminal part 500 may be exposed to the outside of the secondary battery 10 through the terminal hole 110a. A coupling groove 112 and a coupling protrusion 114 may be provided on the inner surface of the upper surface part 110 adjacent to the terminal hole 110a.

[0045] The coupling groove 112 may be formed by forging. The coupling groove 112 may have a circular ring shape based on the center of the upper surface portion 110 of the tank 100, the circular ring shape having a width (e.g., a set or predetermined width). The diameter of the terminal hole 110a may be defined as L1. In this case, the outer diameter of the coupling groove 112 may be formed to be larger than the diameter of the terminal hole 110a. The outer diameter of the coupling groove 112 is based on the diameter of the outer edge of the coupling groove 112 in a direction away from the center of the upper surface portion 110. The length obtained by subtracting the diameter L1 of the terminal hole 110a from the outer diameter of the coupling groove 112 is defined as the width of the coupling groove 112. In other words, based on Figure 3 , the width of the coupling groove 112 can be understood as the radial length of the coupling groove 112 .

[0046] In addition, the depth L3 of the coupling groove 112 may refer to the length of the upper surface portion 110 in the direction of the thickness L2. For example, the depth L3 of the coupling groove 112 is the length between the inner surface and the outer surface of the coupling groove 112. The coupling groove 112 is concavely processed from the inner surface of the upper surface portion 110 by forging. Accordingly, the depth L3 of the coupling groove 112 is formed to be smaller than the thickness L2 of the upper surface portion 110. For example, the depth L3 of the coupling groove 112 may be 10% to 30% smaller than the thickness L2 of the upper surface portion 110.

[0047] When the connection groove 112 is forged from the upper surface portion 110, the metal is pushed and protrudes outward by a processing amount. In this case, the direction in which the metal is pushed is the direction of the cut surface (cut side surface) of the terminal hole 110a or the direction toward the cut surface. In addition, the direction in which the metal is pushed and protrudes is the direction toward the electrode assembly 200. When the connection groove 112 is formed, the pushed and protruding portion can be processed so that its cross-sectional shape becomes a triangle. The protrusion formed in this way is the connection protrusion 114. The protruding height of the connection protrusion 114 should be less than or equal to the height of the inner surface of the upper surface portion 110 of the tank 100 to prevent the connection protrusion 114 from interfering with surrounding components. According to some embodiments, the connection protrusion 114 can be formed adjacent to the connection groove 112 and facing the interior of the tank 100.

[0048] The coupling groove 112 and the coupling protrusion 114 are used to improve or increase the sealing force by increasing the coupling force with the insulator 520, which will be described in more detail below. Accordingly, the leakage of the electrolyte contained in the tank 100 can be prevented or reduced. In addition, the friction between the insulator 520 and the upper surface portion 110 is increased due to the coupling groove 112 and the coupling protrusion 114. Accordingly, the insulator 520 can be very firmly connected to the upper surface portion 110. Accordingly, even when the rivet terminal 510 moves, the insulator 520 will not move. Accordingly, in order to rotate the rivet terminal 510, a very large rotation pressure can be applied. That is, compared with the conventional terminal structure, the rotation pressure of the rivet terminal 510 is increased. Accordingly, the rivet terminal 510 will not rotate due to general external shocks or vibrations occurring in the use environment of the secondary battery. Accordingly, the problem of the rivet terminal 510 rotating due to external force can be prevented or reduced.

[0049] The side portion 130 is integrally formed with the upper surface portion 110 as its upper end is connected to the upper surface portion 110. The lower end of the side portion 130 is open, and the cap assembly 600 is provided at the open end portion. A curling portion 132 may be formed in the side portion 130 adjacent to the lower end. The curling portion 132 may be formed concavely inwardly from the side portion 130. The end portion spaced apart from the curling portion 132 may be bent toward the inside of the can 100 to form a crimping portion 134. Separation of the electrode assembly 200 is prevented by the curling portion 132. The cap assembly 600 may be located between the curling portion 132 and the crimping portion 134. The crimping portion 134 fixes the cap assembly 600 so that the can 100 is sealed.

[0050] The can 100 having the above structure may be formed of steel, steel alloy, aluminum, aluminum alloy or equivalents thereof, but the material is not limited thereto. The electrode assembly 200, the first electrode current collecting plate 300, and the second electrode current collecting plate 400 are accommodated in the can 100 together with the electrolyte.

[0051] like Figure 2 As shown, the electrode assembly 200 may have a form in which the first electrode plate 210, the second electrode plate 220, and the separator 230 interposed therebetween are wound in a cylindrical form. According to some embodiments, the first electrode plate 210 may be a positive electrode plate, and the second electrode plate 220 may be a negative electrode plate. However, the opposite may also be possible.

[0052] In the first electrode plate 210, the positive electrode active material layer may be formed on at least one surface of an aluminum (Al) foil by coating or the like. For example, the positive electrode active material layer may be made of a transition metal oxide (LiCoO 2 、LiNiO 2 、LiMn 2 O 4 The first electrode uncoated portion where the positive electrode active material layer is not formed may be provided in the first electrode plate 210. A plurality of first electrode substrate tabs may be formed by cutting the first electrode uncoated portion into a shape (e.g., a set or predetermined shape) through a notch or the like. According to some embodiments, the first electrode substrate tab may be arranged toward the upper surface portion 110 of the can 100. In addition, the first electrode substrate tab may protrude further upward than the diaphragm 230 to be electrically connected to the first electrode current collecting plate 300.

[0053] In the second electrode plate 220, the negative electrode active material layer may be formed on at least one surface of the copper foil or the nickel foil by coating or the like. For example, the negative electrode active material layer may be formed of graphite, carbon or the like. The second electrode uncoated portion where the negative electrode active material layer is not formed may be provided in the second electrode plate 220. A plurality of second electrode substrate tabs may be formed by cutting the second electrode uncoated portion into a shape (e.g., a set or predetermined shape) via a notch or the like. According to some embodiments, the second electrode substrate tab may be arranged toward the bottom of the tank 100. In addition, the second electrode substrate tab may further protrude downwardly compared to the diaphragm 230 to be electrically connected to the second electrode current collecting plate 400. Some of the second electrode substrate tabs may be welded and electrically connected to the rolled portion 132 of the tank 100.

[0054] The separator 230 may include polyethylene (PE) or polypropylene (PP), but is not limited thereto in the present disclosure. The separator 230 may prevent or reduce an electrical short between the first electrode plate 210 and the second electrode plate 220 and allow only lithium ions to move.

[0055] The electrode assembly 200 having the above-described structure is electrically connected to the first electrode current collecting plate 300 and the second electrode current collecting plate 400 , and is electrically connected to the terminal portion 500 and the can 100 .

[0056] like Figure 2 As shown, the first electrode current collecting plate 300 has a disc shape and may be made of the same material as the first electrode plate 210. For example, the first electrode current collecting plate 300 may be formed of aluminum or an aluminum alloy. The diameter of the first electrode current collecting plate 300 may be smaller than the diameter of the can 100 to prevent the first electrode current collecting plate 300 from being electrically connected to the can 100. The first electrode current collecting plate 300 may be welded in a state where its lower surface is in contact with the first electrode substrate tab.

[0057] Accordingly, the first electrode current collecting plate 300 and the first electrode plate 210 may be electrically connected. In addition, the upper surface of the first electrode current collecting plate 300 may be welded to the rivet terminal 510 of the terminal portion 500, which will be described below. Accordingly, the first electrode current collecting plate 300 and the rivet terminal 510 may be electrically connected. Accordingly, the first electrode plate 210 and the rivet terminal 510 may be electrically connected to each other through the first electrode current collecting plate 300. That is, the first electrode current collecting plate 300 may become a current flow path between the first electrode plate 210 and the rivet terminal 510.

[0058] like Figure 2As shown, the second electrode current collecting plate 400 may include a disc-shaped plate surface portion 410 and a contact portion 420 extending from the plate surface portion 410. The upper surface of the plate surface portion 410 may be welded while in contact with the second electrode substrate tab. Accordingly, the second electrode current collecting plate 400 and the second electrode plate 220 may be electrically connected. To this end, the second electrode current collecting plate 400 may be made of the same material as the second electrode plate 220. For example, the second electrode current collecting plate 400 may be made of copper. According to some embodiments, the contact portion 420 may extend downward from the edge of the plate surface portion 410. The contact portion 420 may be in close contact with the inner surface of the crimping portion 132. To this end, the contact portion 420 may have a curved surface corresponding to the curved surface of the crimping portion 132. For example, the contact portion 420 may be welded and electrically connected to the crimping portion 132. However, the second electrode current collecting plate 400 is not electrically connected to the cap assembly 600.

[0059] At the same time, if Figure 1 and Figure 2 As shown, the terminal portion 500 may include a rivet terminal 510 and at least one insulator 520 for insulating the rivet terminal 510 .

[0060] The rivet terminal 510 is inserted into a terminal hole 110a formed in the upper surface portion 110 of the can 100. The rivet terminal 510 is electrically connected to the first electrode plate 210 through the first electrode current collecting plate 300. The rivet terminal 510 is a terminal coupled to the upper surface portion 110 of the can 100 by a riveting method. The rivet terminal 510 may be inserted into the terminal hole 110a from the outside of the can 100 toward the inside of the can 100.

[0061] In this case, one end of the rivet terminal 510 is located outside the can 100, and the other end is located inside the can 100. When the rivet terminal 510 is coupled, at least one insulator 520 may be inserted between the rivet terminal 510 and the upper surface portion 110 of the can 100 to insulate the can 100 from the rivet terminal 510. In a state where the rivet terminal 510 is inserted into the terminal hole 110a, the inner end portion of the rivet terminal 510 is compressed and deformed by processing such as extrusion, spinning, etc. Accordingly, the rivet terminal 510 may be in close contact with the upper surface portion 110 of the can 100.

[0062] The insulator 520 may be made of an insulating material. The insulator 520 may have a cross-sectional shape that is approximately an "H" shape turned down. The insulator 520 may be used without limitation as long as it is insoluble in the electrolyte and is made of an insulating material. In addition, the insulator 520 may have appropriate elasticity to be tightly coupled with the upper surface portion 110 of the can 100 and the rivet terminal 510 by pressurization. Figure 4, a coupling portion 528 coupled to the coupling groove 112 may be provided on the insulator 520. Figure 2 and Figure 4 As shown, the insulator 520 may include a disc-shaped first portion 522 located outside the upper surface portion 110, a disc-shaped second portion 524 located inside the upper surface portion 110, and a cylindrical third portion 526 connecting the first portion 522 and the second portion 524. The coupling portion 528 may be formed on the second portion 524.

[0063] In addition, the second portion 524 may have a length that fully extends to the outside of the coupling groove 112 of the upper surface portion 110. For example, the length of the second portion 524 may be 2 to 3 times the length of the coupling groove 112. In addition, for example, when there is no separate insulating member between the first electrode current collecting plate 300 and the can 100, the second portion 524 may be provided to be larger than the first electrode current collecting plate 300. The first portion 522 to the third portion 526 may be formed integrally, or may be formed separately and coupled to the upper surface portion 110. This document has described an embodiment according to the present disclosure based on an example in which the first portion 522 to the third portion 526 are formed integrally. The coupling portion 528 is based on Figure 2 is formed to protrude from the upper surface of the second portion 524, and based on Figure 4 The second portion 524 is formed to protrude from the lower surface of the second portion 524. The coupling portion 528 is formed to correspond to the position of the coupling groove 112, and the coupling portion 528 has a convex shape corresponding to the shape of the coupling groove 112. When viewed in a plan view, since the coupling groove 112 is a circular groove, the coupling portion 528 may be a circular ring-shaped protrusion. According to some embodiments, the insulator 520 may additionally include a groove corresponding to the coupling protrusion 114. However, since the insulator 520 is elastic and can be in close contact with the coupling protrusion 114, it is not necessary to provide a groove corresponding to the coupling protrusion 114.

[0064] like Figure 2 As shown, the cap assembly 600 may include a cap plate 610 for sealing the can 100 and a gasket 620 for insulation between the can 100 and the cap plate 610. According to some embodiments, the gasket 620 may be inserted between the cap plate 610 and the side portion 130.

[0065] The cap plate 610 may include a disc-shaped flat surface portion 612, an inclined surface 614 connected to the flat surface portion 612, and an extended surface 616 connected to the inclined surface 614. The flat surface portion 612 may be arranged substantially parallel to the second electrode current collecting plate 400. The inclined surface 614 may extend from the edge of the flat surface portion 612 to be inclined downward. The extended surface 616 may extend from the edge of the inclined surface 614 and may be parallel to the flat surface portion 612. The extended surface 616 may be located between the crimping portion 132 and the crimping portion 134 while being surrounded by the gasket 620. A notch 612a may be formed in the flat surface portion 612. The notch 612a may be broken based on the pressure in the secondary battery 10 being greater than or equal to a pressure (e.g., a set or predetermined pressure). When the notch 612a is broken, the gas in the secondary battery 10 may be discharged. That is, the notch 612a serves as a vent.

[0066] The gasket 620 is located between the lower portion of the crimping portion 132 and the crimping portion 134, and may surround the extension surface 616 of the cap plate 610. The gasket 620 may cover part or all of the extension surface 616. The side where the gasket 620 and the extension surface 616 contact each other may be defined as the inner side, and the side where the gasket 620 contacts the crimping portion 132 may be defined as the outer side. In this case, a portion of the contact portion 420 of the second electrode current collecting plate 400 may be inserted between the outer upper portion of the gasket 620 and the crimping portion 132. Accordingly, the contact portion 420 of the second electrode current collecting plate 400 and the extension surface 616 of the cap plate 610 do not contact each other due to the gasket 620. That is, the gasket 620 may insulate the cap plate 610 and the can 100 from each other, and may insulate the cap plate 610 and the second electrode current collecting plate 400 from each other.

[0067] According to the above structure, the rivet terminal 510 has a positive polarity, and the can 100 has a negative polarity. Accordingly, it has a structure in which both the positive electrode and the negative electrode are located at the top of the can 100.

[0068] Hereinafter, an anti-corrosion material portion (or layer or means) for preventing or reducing corrosion or rust in a region where corrosion or rust may occur in the above-described exemplary cylindrical secondary battery will be described in more detail below.

[0069] As described above, the cap plate 610 is fixed to the can 100 by the crimping portion 134 via the gasket 620 . Figure 5 Schematic diagram briefly illustrating the anti-corrosion part according to some embodiments of the present disclosure. Figure 5As shown, the anti-corrosion material portion 700 may be provided in a region between the end portion of the side portion 130 and the upper surface of the gasket 620. According to some embodiments, the anti-corrosion material portion 700 may be an anti-corrosion liquid. According to some embodiments, the anti-corrosion material portion 700 may be provided at a coupling portion of the side portion 130 and the cover plate 610.

[0070] When the side portion 130 of the can 100 is formed in some manufacturing processes, the end portion of the crimping portion 134, which is the end portion (the end portion opposite to the bottom portion) of the side portion 130, has a cut surface 134a formed by cutting a metal plate which is a material of the can 100. Since the cut surface 134a is a portion exposed to air, there is a risk of corrosion.

[0071] In addition, although the gasket 620 is present between the crimping portion 134 and the cover plate 610, corrosion may occur at the end portion of the crimping portion 134 even due to slight leakage of the electrolyte caused by repeated use of the secondary battery 10. When the corrosion becomes serious, rust may occur and affect the quality of the secondary battery, such as sealing force, etc. The parts susceptible to corrosion or rust are cut parts where the raw material is cut, such as the end portion of the crimping portion 134, welding parts, and formed parts such as trimming parts. Accordingly, in order to prevent or reduce the risk of corrosion or rust, a structure in which an anti-corrosion material part 700 is applied to the above-mentioned part will be proposed.

[0072] like Figure 5 As shown, an example of providing the portion 700 of the anti-corrosion material is the end portion of the crimping portion 134. Figure 5 In some embodiments, the cover plate 610 is positioned closer to the electrode assembly than the end portion of the crimping portion 134. The anti-corrosion material portion 700 may be provided to fully cover the cut surface 134a of the end portion of the crimping portion 134 so that the cut surface 134a is not exposed to the air. In this case, the anti-corrosion material portion 700 may be completely provided in an area (e.g., a set or predetermined area) including the end portion of the crimping portion 134 and the end portion of the liner 620. The liner 620 may not protrude beyond the end portion of the crimping portion 134, or may protrude more. When the liner 620 protrudes more than the crimping portion 134, the anti-corrosion material portion 700 may completely fill the area from the end portion of the crimping portion 134 to the end portion of the liner 620.

[0073] The anti-corrosion material portion 700 may be an anti-corrosion liquid, which is one or a combination of two or more of common materials such as ethylene-vinyl acetate copolymer (EVA), polyethylene (PE) material, polypropylene (PP) material, etc. and hot melt materials such as BU-302 material having heat-resistant and / or flame-retardant properties. Alternatively, the anti-corrosion material portion 700 may be an acrylic or olefin adhesive, a potting material (e.g., a foamed silicone filled between battery cells of a battery pack) and / or a UV solution, a general oil paint, a zinc primer, etc.

[0074] Figure 6 and Figure 7 is a schematic diagram briefly illustrating an anti-corrosion portion according to some embodiments of the present disclosure.

[0075] According to reference Figure 6 In some embodiments, the cover plate 610' may have a curved surface. In this case, the edge of the cover plate 610' may be positioned closer to the electrode assembly than the end portion of the crimping portion 134. However, a portion of the cover plate 610' may protrude further outward than the end portion of the crimping portion 134. In this case, the gasket 620' may be located between the end portion of the crimping portion 134 and the maximum protruding surface of the cover plate 610' (hereinafter, the maximum protruding surface 610a'). In this case, the anti-corrosion material portion 700' may completely fill the area between the end portion of the crimping portion 134 and the maximum protruding surface 610a' of the cover plate 610'. However, this is only an example, and the anti-corrosion material portion 700' may be provided only to the end portion of the crimping portion 134 and the end portion of the gasket 620'. According to some embodiments, the anti-corrosion material portion 700' may cover the end portion of the crimping portion 134 and the end portion of the gasket 620'. According to some embodiments, the anti-corrosion material portion 700 ′ may cover an end portion of the crimping portion 134 , an end portion of the gasket 620 ′, and a portion of the cover plate 610 ′.

[0076] At the same time, according to the reference Figure 7In some embodiments, the cover plate 610" has a straight plate shape, and the edge of the cover plate 610" may be connected to the side portion 130" by welding instead of crimping. In this case, according to some embodiments, a thin insulating film may be provided between the side portion 130" and the cover plate 610", instead of a gasket. In this case, an anti-corrosion material portion 700" may be provided to fully cover the welding portion and the cut surface 134a" of the end portion of the side portion 130". When the anti-corrosion material portion 700" is an anti-corrosion liquid, a protrusion or rib 130a" or 610a" may be provided to prevent the anti-corrosion liquid from flowing to the outside of the side portion 130" or the center of the cover plate 610". The protrusion or rib 130a" or 610a" may be formed on any one or both of the side portion 130" and the cover plate 610". According to some embodiments, the protrusion or rib 130a" or 610a" may protrude from at least one surface of the outer end portion of the side portion 130" and the side of the cover plate 610" adjacent to the welding portion. Exemplary shapes of the protrusion or rib 130a" or 610a" are as follows: Figure 7 The projection or rib 130a" or 610a" may be provided to be lower than the height of the weld bead formed in the welded portion. Figure 7 is a cross-sectional view, so the protrusion or rib 130a" or 610a" is shown as one. However, because the side portion 130" has a cylindrical shape and the cover plate 610" has a circular shape, the protrusion or rib 130a" or 610a" may have a donut shape when viewed from above (e.g., in a plan view). Alternatively, a groove 610b" may be formed in place of the protrusion or rib 610a" on the cover plate 610" to prevent or reduce the flow of the anti-corrosion liquid. According to some embodiments, the groove 610b" may be formed concavely from the surface adjacent to the welding portion. For example, the groove described above may be formed by forging. The groove 610b" may also have a donut shape when viewed from above (e.g., in a plan view).

[0077] Furthermore, in all the above-described embodiments, the anti-corrosion material portion 700 may also be provided in the terminal hole portion.

[0078] Figure 8 is a schematic diagram briefly illustrating an example of an anti-corrosion portion according to some embodiments of the present disclosure.

[0079] like Figure 8 As shown, according to reference Figures 5 to 7All secondary batteries 10 of some embodiments may have the same terminal portion structure. The above-mentioned anti-corrosion material portion may also be provided in the terminal hole 110a and the peripheral area 150 to which the above-mentioned rivet terminal 510 is connected. According to some embodiments, the anti-corrosion material portion may be provided at the connection portion of the terminal hole 110a and the terminal portion 500. According to some embodiments, the anti-corrosion material portion may cover a portion of the cut surface of the terminal hole 110a and a portion of the upper surface portion 110 adjacent to the terminal hole 110a. The terminal hole 110a is a portion of the cut surface formed by cutting the upper surface portion 110 of the tank 100, and therefore may also be susceptible to corrosion. Accordingly, for example, an anti-corrosion liquid may be applied to cover the terminal hole 110a and its peripheral area 150.

[0080] The cylindrical secondary battery according to some embodiments of the present disclosure is corrosion-resistant, so that the cut surface or welding surface that is prone to corrosion or rust is not exposed to the air. Accordingly, the occurrence of corrosion or rust on the cut surface or welding surface can be prevented or reduced.

[0081] The above description illustrates and describes aspects of some embodiments of the present disclosure, and the present disclosure is not limited to the above-mentioned embodiments, and as claimed in the claims and their equivalents, the technical spirit of the present disclosure will be deemed to have reached the extent that any technician in the field can make various modifications without departing from the spirit and scope of the embodiments according to the present disclosure.

Claims

1. A cylindrical secondary battery, comprising: Electrode assembly; a can in which the electrode assembly is accommodated and includes an upper surface portion at one end and formed with a terminal hole and a cylindrical side portion extending downward from the upper surface portion; a terminal portion coupled to the terminal hole and electrically connected to the electrode assembly; a cover plate coupled to the end portion of the side portion; as well as An anti-corrosion material portion is at a connection portion between the side portion and the cover plate.

2. The cylindrical secondary battery according to claim 1, wherein: The side portion includes a crimping portion formed concavely above the upper surface of the cover plate and a crimping portion spaced apart from the crimping portion and having an end portion formed to be bent inwardly; and The cover plate is between the crimping portion and the crimping portion. 3 . The cylindrical secondary battery according to claim 2 , further comprising a gasket interposed between the cap plate and the side portion. 4 . The cylindrical secondary battery according to claim 3 , wherein the anticorrosion material partially covers the end portion of the crimping portion. 5 . The cylindrical secondary battery according to claim 3 , wherein the anti-corrosion material partially covers the end portion of the crimping portion and the end portion of the gasket. 6 . The cylindrical secondary battery according to claim 3 , wherein the anti-corrosion material partially covers the end portion of the crimping portion, the end portion of the gasket, and a portion of the cap plate. 7 . The cylindrical secondary battery according to claim 1 , wherein the cap plate is welded to the side portion. 8 . The cylindrical secondary battery according to claim 7 , wherein the anti-corrosion material partially covers the end portion of the side portion. 9 . The cylindrical secondary battery according to claim 7 , wherein the anti-corrosion material partially covers a welding portion of the end portion of the side portion and the cap plate. 10 . The cylindrical secondary battery according to claim 9 , wherein the anti-corrosion material portion is an anti-corrosion liquid. 11 . The cylindrical secondary battery according to claim 10 , further comprising a protrusion or a rib protruding from an outer end portion of the side portion and at least one surface of a side of the cap plate adjacent to the welding portion. 12 . The cylindrical secondary battery according to claim 11 , wherein the protrusion or the rib has a height lower than a weld bead formed in the welding portion of the cap plate. 13 . The cylindrical secondary battery according to claim 12 , wherein the protrusion or the rib has a circular ring shape. 14 . The cylindrical secondary battery according to claim 10 , wherein the cap plate further comprises a groove concavely formed from a surface of the cap plate adjacent to the welding portion.

15. A cylindrical secondary battery comprising: Electrode assembly; a can in which the electrode assembly is accommodated and includes an upper surface portion at one end and formed with a terminal hole and a cylindrical side portion extending downward from the upper surface portion; a terminal portion coupled to the terminal hole and electrically connected to the electrode assembly; a cover plate coupled to the end portion of the side portion and insulated from the tank; as well as An anti-corrosion material portion is provided at a connection portion between the terminal hole and the terminal portion. 16 . The cylindrical secondary battery according to claim 15 , wherein the anti-corrosion material partially covers a portion of a cut surface of the terminal hole and a portion of the upper surface portion adjacent to the terminal hole. 17 . The cylindrical secondary battery according to claim 16 , wherein the anti-corrosion material portion is an anti-corrosion liquid. 18 . The cylindrical secondary battery according to claim 15 , further comprising a coupling groove and a coupling protrusion formed by forging adjacent to the terminal hole.

19. The cylindrical secondary battery according to claim 18, wherein: The coupling groove is formed concavely from the surface of the upper surface portion; The depth of the coupling groove is less than the thickness of the upper surface portion; and The coupling protrusion is formed adjacent to the coupling groove and faces the interior of the tank.

20. The cylindrical secondary battery according to claim 19, wherein the terminal portion includes a rivet terminal inserted into the terminal hole to be electrically connected to the electrode assembly and at least one insulator interposed between the rivet terminal and the upper surface portion of the can to insulate the rivet terminal from the upper surface portion of the can.

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