Button-type secondary battery

Abstract

The present invention includes: an electrode assembly in which electrodes and separators are wound while being stacked on each other, and electrode tabs having different polarities from each other protrude from upper and lower surfaces of the electrode assembly, respectively; a can having a bottom connected to one of the electrode tabs and a side wall portion extending vertically along a periphery of the bottom, below the electrode assembly installed inside thereof; and a top cover assembly including a terminal portion connected to the other electrode tab and a plate coupled to and insulated from the terminal portion and having an edge coupled to an upper end of the side wall portion, the top cover assembly enclosing the can when the electrode assembly is installed in the can, wherein an end of the edge of the plate is coupled by welding after a point where the end of the edge of the plate meets the upper end of the side wall portion is provided. According to the present invention having the above-described configuration, since the welding is performed after the point where the end of the edge of the plate meets the upper end of the side wall portion is provided, more stable welding can be achieved and the welding quality can be improved.

Description

TECHNICAL FIELD

[0001] This application claims priority to Korean Patent Application No. 10-2020-0131453, filed on October 12, 2020, which is incorporated herein in its entirety by reference.

[0002] The present application relates to a coin type secondary battery, and more particularly, to a coin type secondary battery in which welding is performed in a state in which a top cover assembly is stably disposed on an upper end of a side wall of a can, to more easily perform a welding process. BACKGROUND

[0003] A coin type battery is generally used as a coin type battery, or has a thin coin shape, and is widely used in various devices such as a remote controller, a clock, a toy, a computer part.

[0004] Such a coin type battery is mainly manufactured as a non-rechargeable primary battery, but as a small-sized device is developed, the coin type battery is also widely manufactured as a rechargeable and dischargeable secondary battery. In addition, like a coin type secondary battery or a cylindrical or pouch type secondary battery, the coin type secondary battery also has a structure in which an electrode assembly and an electrolyte are embedded in a case to repeatedly perform charging and discharging.

[0005] In the coin type battery, when the electrode assembly is mounted on the lower can, the upper can is press-fitted onto the lower can so as to be coupled. However, in order to maximize the internal space and prevent deformation due to press-fitting, a structure in which a top cover assembly 1 is welded to be coupled to the can 20 is also disclosed.

[0006] That is, referring to Figure 1 a and Figure 1 b , Figure 1 a and Figure 1 b respectively illustrate cross-sectional views before and after a plate is coupled to a can in a coin type secondary battery according to the related art, the coin type secondary battery coupled by welding has a flat columnar shape similar to a bowl shape and includes a can 20 having an upper side with an opening and a top cover assembly 1 coupled by welding to close the open upper side of the can 20.

[0007] The can 20 has a bottom 22 located on a lower side when the electrode assembly 10 is mounted and a side wall 21 extending vertically along a periphery of the bottom 22. In addition, in a space in an inner side of the side wall 21 above the bottom 22, the electrode assembly 10 in which a positive electrode, a separator, and a negative electrode are stacked and an electrolyte are mounted. Here, in the electrode assembly 10, a negative electrode tab 10b protruding from the negative electrode is electrically connected to a bottom surface of the can 20, and a positive electrode tab 10a protruding from the positive electrode is electrically connected to a positive electrode terminal 40 constituting the top cover assembly 1.

[0008] The positive terminal 40 is coupled to the plate 50, and the gasket 60 is interposed between the positive terminal 40 and the plate 50 such that the positive terminal 40 and the plate 50 are electrically insulated from each other. That is, the plate 50 has a disc shape that can be placed on the side wall 21 of the can 20, and has a structure in which a hole is punched in the center thereof and the positive terminal 40 and the gasket 60 are installed in the hole.

[0009] In the structure according to the related art, the plate 50 is welded by laser at a point in contact with the side wall 21 of the can 20 in a state in which the height thereof is adjusted to match the height of the side wall 21.

[0010] However, if stable setting or temporary fixing is not achieved at a point at which the upper end of the side wall 21 and the edge portion of the plate 50 contact each other, incomplete welding can be performed, resulting in a problem of electrolyte leakage. SUMMARY

[0011] TECHNICAL PROBLEM

[0012] Accordingly, the primary object of the present application is to provide a coin-type secondary battery in which an edge of a plate is more stably disposed on an upper end of a side wall, so that welding is easily and more completely performed.

[0013] TECHNICAL SOLUTION

[0014] A coin-type secondary battery according to the present application for achieving the above object includes an electrode assembly in which electrodes and separators are wound in a stacked state, and electrode tabs having different polarities protrude from top and bottom surfaces thereof, respectively; a can including a bottom disposed below when the electrode assembly is installed and connected to one electrode tab, and a side wall extending vertically along a periphery of the bottom; and a top cap assembly provided with a terminal portion connected to the other electrode tab, and a plate coupled to be insulated from the terminal portion and having an edge coupled to an upper end of the side wall, wherein the top cap assembly is coupled to enclose the can when the electrode assembly is installed in the can, and wherein an end portion of the edge of the plate is welded to be coupled after being disposed at a point in contact with the upper end of the side wall.

[0015] In the present application, the upper end of the side wall can be curved in a direction in which an inner diameter thereof is enlarged, and the end portion of the edge of the plate can be coupled to be in close contact with an inner circumferential surface of the upper end of the side wall.

[0016] In the present application, a protrusion formed with a stepped portion can be disposed on an inner circumferential surface at the upper end of the side wall, and the end portion of the edge of the plate can be coupled to be disposed on the protrusion, and the upper end of the side wall can be curved to have a shape protruding outward from an outer circumferential surface thereof.

[0017] In the present invention, an inclined surface can be formed on the upper end of the sidewall to have an inner diameter that gradually increases upward, and the inclined surface can be formed on the end of the edge of the plate so that the top surface of the plate has the same height as the uppermost end of the sidewall.

[0018] In the present invention, the upper end of the sidewall can be formed in a shape that is curved inward, and a protrusion can also be formed on the lower portion of the end of the edge of the plate so as to be disposed on the end of the sidewall.

[0019] In the present invention, the upper end of the sidewall can have a groove whose upper side and outer side are connected to each other to form a concave shape, and a protrusion disposed on the upper end of the sidewall and inserted into the groove can protrude from the end of the edge of the plate.

[0020] In the present invention, a protrusion formed with a stepped portion can be disposed on the inner circumferential surface at the upper end of the sidewall, and the end of the edge of the plate can be coupled so as to be disposed on the protrusion.

[0021] In the present invention, a curved portion that expands outward from the upper end of the sidewall and is curved downward when the plate is disposed on the sidewall can be provided at the end of the edge of the plate.

[0022] In the present invention, the upper end of the sidewall can be curved in a direction in which the inner diameter thereof expands, and the end of the edge of the plate can be coupled so as to be in close contact with the inner circumferential surface of the upper end of the sidewall, wherein the portion of the end of the edge of the plate in close contact with the inner circumferential surface of the upper end of the sidewall can have a shape that is curved upward.

[0023] In the present invention, the upper end of the sidewall can be curved in a shape that protrudes outward, wherein the upper side can be flat, and the upper plate can be coupled so as to be disposed on the flat end of the sidewall.

[0024] In the present invention, a protrusion formed with a stepped portion can be formed on the lower side at the end of the edge of the plate, and the protrusion can be coupled so as to be disposed on the upper end of the sidewall.

[0025] In the present invention, a protrusion formed with a stepped portion can be disposed on the inner circumferential surface at the upper end of the sidewall, and the protrusion can be coupled so as to be disposed on the upper end of the sidewall, wherein the portion of the end of the edge of the plate in close contact with the inner circumferential surface of the sidewall can have a shape that is curved upward.

[0026] In the present invention, each of the end of the edge of the plate and the upper end of the sidewall can have a shape in which a recess and a protrusion are repeated along the periphery thereof, and the protrusion formed on the sidewall can be fitted into the recess formed in the plate, and the protrusion formed on the plate can be fitted into the recess formed in the sidewall.

[0027] Advantageous Effects

[0028] In the present application having the above-described configuration, since the welding is performed after the point where the edge of the plate meets the upper end of the side wall, the welding can be more stably performed, thereby improving the welding quality.

[0029] Further, the number of welding points can be increased to improve the coupling force by welding, and the welding points and the electrode assembly can be maximally spaced apart from each other to prevent the electrode assembly from being thermally damaged. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 a is a view illustrating a cross section before a plate is coupled to a can in a button-type secondary battery according to the related art.

[0031] Figure 1 b is a view illustrating a cross section after a plate is coupled to a can in a button-type secondary battery according to the related art.

[0032] Figure 2 is an enlarged view illustrating a coupling portion between a can and a plate according to a first embodiment of the present application.

[0033] Figure 3 is an enlarged view illustrating a coupling portion between a can and a plate according to a second embodiment of the present application.

[0034] Figure 4 is an enlarged view illustrating a coupling portion between a can and a plate according to a third embodiment of the present application.

[0035] Figure 5 is an enlarged view illustrating a coupling portion between a can and a plate according to a fourth embodiment of the present application.

[0036] Figure 6 is an enlarged view illustrating a coupling portion between a can and a plate according to a fifth embodiment of the present application.

[0037] Figure 7 is an enlarged view illustrating a coupling portion between a can and a plate according to a sixth embodiment of the present application.

[0038] Figure 8 is an enlarged view illustrating a coupling portion between a can and a plate according to a seventh embodiment of the present application.

[0039] Figure 9 is an enlarged view illustrating a coupling portion between a can and a plate according to an eighth embodiment of the present application.

[0040] Figure 10 is an enlarged view illustrating a coupling portion between a can and a plate according to a ninth embodiment of the present application.

[0041] Figure 11 FIG. 10 is an enlarged view illustrating a coupling portion between a can and a plate according to a tenth embodiment of the present application.

[0042] Figure 12 FIG. 11 is an enlarged view illustrating a coupling portion between a can and a plate according to an eleventh embodiment of the present application.

[0043] Figure 13 FIG. 12 is a plan view and a side view illustrating a state in which a can and a plate are coupled to each other according to a twelfth embodiment of the present application. DETAILED DESCRIPTION

[0044] Hereinafter, preferred embodiments of the present application will be described in detail by referring to the attached drawings, in a manner that those skilled in the art to which the present application pertains can easily implement the technical idea of the present application. However, the present application can be implemented in many different forms and should not be interpreted as being limited to the embodiments set forth herein.

[0045] In order to clearly describe the present application, portions unrelated to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

[0046] In addition, the terms or words used in the present specification and claims should not be interpreted as being limited to the common or dictionary meanings, but should be interpreted as having a concept meeting the principles and novelty of the present application based on the concept that the inventor can properly define one term or word in order to describe and explain his or her invention in the best way. Therefore, the embodiment of the present application should be considered in a descriptive sense only and not for purposes of limitation.

[0047] The present application relates to a button-type secondary battery having a structure in which a top cap assembly 1 is coupled to a can 20 by welding, and more particularly, to a button-type secondary battery in which a plate 50 of the top cap assembly 1 is welded in a state of being disposed on an upper end of a side wall 21 of the can 20 to more easily perform a welding process.

[0048] The button-type secondary battery according to the present application has a structure in which, when an electrode and a separator are wound in a stacked state as in the structure according to the related art, and an electrode assembly 10 (having electrode tabs of different polarities protruding from a top surface and a bottom surface thereof, respectively) is mounted in a can, an edge of a plate 50 constituting the top cap assembly 1 is welded to the can 20.

[0049] The can 20 is placed below when the electrode assembly 10 is mounted, and includes a bottom 22 connected to any one of the electrode tabs (for example, a negative electrode tab) and a side wall 21 extending vertically upward along a periphery of the bottom 22.

[0050] The top cover assembly 1 is provided with a terminal portion 40 connected to another electrode terminal (for example, a positive electrode terminal) and a plate 50 coupled to be insulated from the terminal portion 40 by a gasket 60 and the edge of which is coupled to the upper end of the side wall. Thus, when the electrode assembly 10 is installed in the can 20, the top cover assembly 1 is coupled to close the can 20.

[0051] That is, after the edge of the plate 50 is provided at a point where the upper end of the side wall 21 is connected, welding is performed to couple the plate 50 to the side wall 21.

[0052] In the present application, as an embodiment, various structures are provided in which the edge of the plate 50 is provided on the upper end of the side wall 21.

[0053] Figures 2 to 12 is an enlarged view illustrating a coupling portion between a can and a plate according to the first to eleventh embodiments of the present application, and Figure 13 is a plan view and a side view illustrating a state in which a can and a plate are coupled to each other according to the twelfth embodiment of the present application. Hereinafter, embodiments according to the present application will be described with reference to the accompanying drawings.

[0054] First embodiment

[0055] Referring to Figure 2 , the can 20 provided in the present embodiment has a structure in which the upper end of the side wall 21 is curved along the periphery in a direction in which the inner diameter is enlarged. In addition, the plate 50 is coupled in such a manner that the edge thereof is in close contact with the inner peripheral surface of the upper end of the side wall 21. Here, the upper end of the side wall 21 and the top surface of the plate 50 are coupled to have the same height.

[0056] In this coupling structure, before welding of the can 20 and the plate 50 is performed, the edge of the plate 50 can be provided in contact with the inner peripheral surface of the can 20, and in addition, the height of the electrode assembly 10 can be maximized based on the same total height.

[0057] Second embodiment

[0058] Referring to Figure 3 , the can 20 provided in the present embodiment has a protrusion (a portion in which an "L"-shaped groove for placing a plate is formed in Figure 3 ) having a stepped portion (a difference in height) provided on the inner peripheral surface at the upper end of the side wall 21, and the edge of the plate 50 is coupled to be placed on the protrusion. The upper end of the side wall 21 is curved to have a shape protruding outward from the outer peripheral surface. In addition, the top surface of the plate 50 is formed at a position higher than the upper end of the side wall 21.

[0059] In this connection structure, before the tank 20 and plate 50 are welded, the edge of plate 50 can be positioned to contact the inner circumferential surface of tank 20. Here, when tank 20 and plate 50 have the same total height, the probability of thermal damage to the diaphragm provided in electrode assembly 10 can be reduced because the welding points of tank 20 and plate 50 are relatively far apart from each other. In addition, since the upper end of sidewall 21 has a structure that is bent into a shape that protrudes outward from the outer circumferential surface, plate 50 can be supported more firmly.

[0060] Third embodiment

[0061] Reference Figure 4 The tank 20 provided in this embodiment has an inclined surface formed on the upper end of the side wall 21 (in Figure 4 The surface forming the oblique line has an upwardly increasing inner diameter. In addition, an oblique surface is also formed at the end of the edge of the plate 50, so that the top surface of the plate 50 has the same height as the uppermost end of the side wall.

[0062] In this connection structure, before welding the tank 20 and the plate 50, the edge of the plate 50 can be positioned to contact the inner circumferential surface of the tank 20, and additionally, the height and diameter of the electrode assembly 10 can be maximized based on the same total height. That is, the dimensions of the internal space of the tank 20 can be maximized.

[0063] Fourth embodiment

[0064] Reference Figure 5 In this embodiment, the can 20 is formed such that the upper end of the sidewall 21 curves inward. Furthermore, a protrusion is formed at the lower end of the edge of the plate 50. Figure 5 Formed in the plate (The portion of the groove) is provided so that it can be set on the end of the side wall 21.

[0065] In this connection structure, before the tank 20 and plate 50 are welded, the edge of plate 50 can be configured to contact the inner circumferential surface of tank 20. Here, when tank 20 and plate 50 have the same total height, the probability of thermal damage to the diaphragm provided in electrode assembly 10 can be reduced because the welding points of tank 20 and plate 50 are relatively far apart from each other.

[0066] Fifth embodiment

[0067] Reference Figure 6 The can 20 provided in this embodiment has a groove 23 ( Figure 6the "L" shaped recessed portion in the side wall 21), the upper side and the outer side of the groove 23 are connected to each other to form a recessed shape, and the end of the edge of the plate 50 is disposed on the upper end of the side wall 21. Here, the protrusion 51 inserted into the groove 23 protrudes.

[0068] In this coupling structure, the edge of the plate 50 can be disposed on the can 20 before performing welding of the can 20 and the plate 50, and in addition, the height of the electrode assembly 10 can be maximized based on the same total height. Further, the contact area increases as many as the number of contact points between the protrusion 51 and the groove 23 to increase the weldable area on which welding is performed between the plate 50 and the can 20.

[0069] Sixth embodiment

[0070] Referring to Figure 7 , the can 20 provided in the present embodiment has a protrusion formed with a stepped portion (a portion formed in an "L" shape in the side wall 21), the protrusion is disposed on the inner circumferential surface at the upper end of the side wall 21, and the end of the edge of the plate 50 is coupled to be placed on the protrusion. Figure 7

[0071] In this coupling structure, the edge of the plate 50 can be disposed on the can 20 before performing welding of the can 20 and the plate 50, and in addition, the height of the electrode assembly 10 can be maximized based on the same total height. Further, since the movement of the plate 50 after being disposed on the protrusion is limited, welding can be more stably and easily performed.

[0072] Seventh embodiment

[0073] Referring to Figure 8 , in the plate 50 provided in the present embodiment, a bent portion 54 that is expanded outward from the upper end of the side wall 21 and is bent downward is provided at the end of the edge of the plate 50 when the plate 50 is disposed on the side wall 21.

[0074] In this coupling structure, the edge of the plate 50 can be disposed on the can 20 before performing welding of the can 20 and the plate 50. Here, when the can 20 and the plate 50 have the same total height, since the welding points of the can 20 and the plate 50 are relatively far apart from each other, the probability of thermal damage of the separator disposed in the electrode assembly 10 can be reduced. Further, welding can be performed in the horizontal direction and the diagonal direction to improve the convenience of the welding process.

[0075] Eighth embodiment

[0076] Referring to Figure 9 ​In the tank 20 provided in the present embodiment, the upper end of the side wall 21 is bent in a direction in which the inner diameter thereof is enlarged, as in the structure provided in the first embodiment. Further, the end portion of the edge of the plate 50 is coupled so as to be in close contact with the inner peripheral surface of the upper end of the side wall 21. Here, the portion in which the end portion of the edge of the plate 50 is in close contact with the inner peripheral surface of the upper end of the side wall 21 is bent upward.

[0077] In this coupling structure, the edge of the plate 50 can be disposed in contact with the inner peripheral surface of the tank 20 before the tank 20 and the plate 50 are welded. Here, when the tank 20 and the plate 50 have the same total height, since the welding points of the tank 20 and the plate 50 are relatively far apart from each other, the probability that the diaphragm provided in the electrode assembly 10 can be thermally damaged can be reduced. Further, the contact area in which welding is performed between the tank 20 and the plate 50 can be increased to further improve the bonding force.

[0078] Ninth embodiment

[0079] Referring to Figure 10 In the tank 20 provided in the present embodiment, the upper end of the side wall 21 is bent to have a shape protruding outward, the upper side of the side wall 21 is flat, and the plate 50 is coupled so as to be placed on the flat end portion of the side wall 21.

[0080] In this coupling structure, the edge of the plate 50 can be disposed on the tank 20 before the tank 20 and the plate 50 are welded. Here, when the tank 20 and the plate 50 have the same total height, since the welding points of the tank 20 and the plate 50 are relatively far apart from each other, the probability that the diaphragm provided in the electrode assembly 10 can be thermally damaged can be reduced. Further, the welding area can be increased to increase the bonding force, and since horizontal welding can be performed, the convenience of the welding process can be improved.

[0081] Tenth embodiment

[0082] Referring to Figure 11 The plate 50 provided in the present embodiment has a protrusion (a portion recessed in a Figure 11 shape in the end portion of the edge thereof formed at the lower side, and the protrusion is coupled so as to be placed on the upper end of the side wall 21.

[0083] In this coupling structure, the edge of the plate 50 can be disposed in contact with the inner peripheral surface of the tank 20 before welding of the tank 20 and the plate 50 is performed, and in addition, the height of the electrode assembly 10 can be maximized based on the same total height.

[0084] Eleventh embodiment

[0085] Referring to Figure 12The can 20 provided in this embodiment has a protrusion with a stepped portion (in Figure 12 The protrusion (in an "L"-shaped recess) is located on the inner circumferential surface of the sidewall 21 at its upper end, and the edge of the plate 50 is attached to the protrusion. Furthermore, the portion of the edge of the plate 50 that is in close contact with the inner circumferential surface of the sidewall 21 has an upwardly curved shape.

[0086] In this connection structure, before the tank 20 and plate 50 are welded, the edge of plate 50 can be positioned to contact the inner circumferential surface of tank 20. Here, when tank 20 and plate 50 have the same total height, the probability of thermal damage to the diaphragm disposed in electrode assembly 10 can be reduced because the welding points of tank 20 and plate 50 are relatively far apart from each other. Furthermore, welding can be performed in both horizontal and diagonal directions to improve the convenience of the welding process.

[0087] Twelfth embodiment

[0088] Reference Figure 13 The structure provided in this embodiment has the following shape: recesses 24 and 53 and protrusions 25 and 52 are repeated along the periphery at the edge of the plate 50 and the upper end of the side wall 21.

[0089] In addition, the protrusion 25 formed on the sidewall 21 is connected to be fitted into the recess 53 formed in the plate 50, and the protrusion 52 formed on the plate 50 is connected to be fitted into the recess 24 formed in the sidewall 21.

[0090] In this connection structure, the edge of plate 50 can be set on tank 20 before tank 20 and plate 50 are welded, and since the recess 53 and protrusion 52 of plate 50 are respectively fitted into the protrusion 25 and recess 24 of sidewall 21, welding can be performed in a temporary connection state. Therefore, the welding process can be performed more easily. Based on the same total height, the height of electrode assembly 10 can be maximized.

[0091] In the button-type secondary battery of the present invention with the above-described embodiment, since the edge of the plate 50 is welded after being disposed at the point where it connects with the upper end of the sidewall 21, the welding can be performed more stably to improve the welding quality.

[0092] Although embodiments of the invention have been described with reference to specific examples, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.

[0093] [Description of reference numerals in the attached figures]

[0094] 10: Electrode assembly

[0095] 20: tank

[0096] 21: side wall

[0097] 50: plate

Claims

1.A coin-type secondary battery comprising: an electrode assembly in which electrodes and separators are wound in a stacked state, and electrode tabs of different polarities protrude from a top surface and a bottom surface of the electrode assembly, respectively; a can accommodating the electrode assembly and including a bottom connected to one of the electrode tabs and a side wall extending vertically along a periphery of the bottom; and a top cover assembly provided with a terminal portion connected to the other of the electrode tabs and a plate coupled to be insulated from the terminal portion and having an edge coupled to an upper end of the side wall, wherein the top cover assembly is coupled to enclose the can when the electrode assembly is installed in the can, wherein an end portion of the edge of the plate is welded to be coupled after being placed on a point where the upper end of the side wall is met, and wherein a projection formed with a stepped portion is provided on an inner circumferential surface at the upper end of the side wall, and the end portion of the edge of the plate is coupled to be placed on the projection, and the upper end of the side wall is bent to have a shape protruding outward from an outer circumferential surface thereof. 2.A coin-type secondary battery comprising: an electrode assembly in which electrodes and separators are wound in a stacked state, and electrode tabs of different polarities protrude from a top surface and a bottom surface of the electrode assembly, respectively; a can accommodating the electrode assembly and including a bottom connected to one of the electrode tabs and a side wall extending vertically along a periphery of the bottom; and a top cover assembly provided with a terminal portion connected to the other of the electrode tabs and a plate coupled to be insulated from the terminal portion and having an edge coupled to an upper end of the side wall, wherein the top cover assembly is coupled to enclose the can when the electrode assembly is installed in the can, wherein an end portion of the edge of the plate is welded to be coupled after being placed on a point where the upper end of the side wall is met, and wherein the upper end of the side wall is formed in a shape bent inward, and a projection is further formed on a lower portion of the end portion of the edge of the plate so that the projection is placed on an end portion of the side wall. ​ ​

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