Rechargeable battery

Abstract

A rechargeable battery includes: an electrode assembly including a first electrode, a second electrode, and a separator between the first electrode and the second electrode; a case connected to the first electrode and accommodating the electrode assembly, and including an opening to receive the electrode assembly; a cover plate coupled to the case to cover a peripheral area of the opening and including a through hole to expose a central area of the opening; and a terminal plate connected to the second electrode to be insulated from and coupled to the cover plate, and including a flange portion covering the through hole and a protruding portion protruding from the flange portion and passing through the through hole.

Description

Technical Field

[0001] Aspects of embodiments of the present disclosure relate to a rechargeable battery. Background Art

[0002] Generally speaking, a rechargeable battery is a battery that can be charged and discharged repeatedly.

[0003] In recent years, as demand for wearable devices such as headphones, earphones, smart watches, and body-attached medical devices using wireless communication such as Bluetooth has increased, demand for ultra-small rechargeable batteries mounted in wearable devices has increased.

[0004] This ultra-small rechargeable battery includes an electrode assembly including two electrodes; a case accommodating the electrode assembly and connected to one electrode of the electrode assembly; and a terminal plate sealing the electrode assembly together with the case and connected to the other electrode of the electrode assembly.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. Summary of the Invention

[0006] According to aspects of one or more embodiments, there is provided a rechargeable battery including a terminal plate that tightly seals an electrode assembly together with a case and is securely connected to electrodes of the electrode assembly together (eg, simultaneously).

[0007] According to one or more embodiments, a rechargeable battery includes: an electrode assembly including a first electrode, a second electrode, and a separator between the first electrode and the second electrode; a shell connected to the first electrode and accommodating the electrode assembly, and including an opening to receive the electrode assembly; a cover plate coupled to the shell to cover a peripheral area of the opening and including a through hole to expose a central area of the opening; and a terminal plate connected to the second electrode to be insulated from the cover plate and bonded to the cover plate, and including a flange portion covering the through hole and a protrusion protruding from the flange portion and passing through the through hole, wherein a ratio of a diameter of the protrusion to a diameter of the flange portion is 1 / 10 to 1 / 3.

[0008] The rechargeable battery may further include a heat fusion layer between the cap plate and the flange portion to insulate and bond the cap plate and the flange portion.

[0009] The heat fusion layer may melt at a predetermined temperature.

[0010] The flange portion may be disposed on the cap plate, and the protrusion may be connected to the second electrode from the flange portion through the through hole.

[0011] The electrode assembly may further include: a first electrode tab extending from the first electrode and welded to the housing; and a second electrode tab extending from the second electrode and welded to the protrusion of the terminal plate.

[0012] The flange portion may have a wider area than the protrusion.

[0013] The flange portion may have a thinner thickness than the protrusion.

[0014] The flange portion and the protrusion may be integrally formed.

[0015] The housing and the cover plate may have the same polarity as the first electrode, and the terminal plate may have the same polarity as the second electrode.

[0016] The diameter of the flange portion may be smaller than the diameter of the housing.

[0017] According to aspects of one or more embodiments, there is provided a rechargeable battery including a terminal plate that tightly seals an electrode assembly together with a housing and is firmly connected to the electrodes of the electrode assembly (e.g., simultaneously). BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a perspective view of a rechargeable battery according to an embodiment.

[0019] Figure 2 is a cross-sectional view taken along line II-II in Figure 1 in.

[0020] Figure 3 is a table showing experimental examples demonstrating the effects of a rechargeable battery according to an embodiment.

[0021] DESCRIPTION OF REFERENCE NUMERALS

[0022] 100: Electrode assembly 200: Housing

[0023] 300: Cover plate 400: Terminal plate

[0024] 410: Flange portion 420: Protrusion DETAILED DESCRIPTION

[0025] The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As will be appreciated by those skilled in the art, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the invention. The drawings and the description are to be regarded as illustrative rather than restrictive. Like reference numerals throughout the specification refer to like elements.

[0026] In addition, unless otherwise expressly stated to the contrary, it should be understood that terms such as "comprising", "including", or "having" used in this specification indicate the presence of the stated features, numbers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0027] Also, in this specification, it should be understood that when a component is referred to as being "connected" or "coupled" to another component, it can be directly connected or coupled to the other component, or can be connected or coupled to the other component by means of one or more other components therebetween.

[0028] Unless the context clearly indicates otherwise, the singular forms shall include the plural forms.

[0029] It should be understood that although terms such as "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element may be referred to as a "second" element, and similarly, a second element may be referred to as a "first" element, without departing from the scope of the exemplary embodiments of the inventive concept. Unless the context clearly indicates otherwise, terms in the singular form may include the plural forms.

[0030] In addition, terms such as "below", "under", "above", "over", etc. are used to describe the relationships of the structures shown in the figures. However, the terms are used as relative concepts and are described with reference to the directions indicated in the accompanying drawings.

[0031] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which the inventive concept pertains. It should also be understood that terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and should not be interpreted in an ideal or overly formal sense unless they are so defined herein.

[0032] Next, reference is made to Figure 1 and Figure 2 describe a rechargeable battery according to an embodiment.

[0033] A rechargeable battery according to one or more embodiments is an ultra-small rechargeable battery and can be a coin-type battery or a button-type battery, but is not limited thereto, and in another embodiment, can be a cylindrical or needle-type battery.

[0034] Here, the coin-type battery or button-type battery is a thin coin-type battery or button-type battery, and may refer to a battery having a height-to-diameter ratio of 1 or less, but is not limited thereto. In one embodiment, the coin-type battery or button-type battery is cylindrical and has a circular horizontal cross-section, but the present invention is not limited thereto, and in other embodiments, the horizontal cross-section may be elliptical or polygonal. At this time, the diameter may refer to the maximum distance in the horizontal direction of the battery, and the height may refer to the maximum distance in the vertical direction of the battery (the distance from the flat bottom surface to the flat top surface).

[0035] Figure 1 is a perspective view of a rechargeable battery according to an embodiment; and Figure 2 is a cross-sectional view taken along the line ll-ll of Figure 1 .

[0036] Referring to Figure 1 and Figure 2 , a rechargeable battery 1000 according to an embodiment includes an electrode assembly 100, a case 200, a cover plate 300, a terminal plate 400, and a thermally fused layer 500.

[0037] The electrode assembly 100 is accommodated in the case 200. The lower part of the electrode assembly 100 faces the lower part of the case 200, and the upper part of the electrode assembly 100 faces the cover plate 300 and the terminal plate 400 that cover the opening 210 of the case 200. In one embodiment, both the upper and lower parts of the electrode assembly 100 may have a planar shape and may be parallel to each other, but are not limited thereto.

[0038] The electrode assembly 100 includes a first electrode 110, a second electrode 120, a separator 130, a first electrode tab 140, and a second electrode tab 150.

[0039] The first electrode 100 and the second electrode 120 are separated from each other, and a separator 130 including an insulating material is disposed between the first electrode 110 and the second electrode 120. In one embodiment, the first electrode 110 may be an anode and the second electrode 120 may be a cathode, but the present invention is not limited thereto, and in another embodiment, the first electrode 110 may be a cathode and the second electrode 120 may be an anode.

[0040] In one embodiment, the first electrode 110 has a strip shape extending in one direction, and includes an anode coating region that is a region of a current collector to which an anode active material layer is coated on a metal foil (e.g., a copper foil); and an anode uncoated region that is a region where the active material is not coated. The anode uncoated region may be provided at an end portion in the extending direction of the first electrode 110.

[0041] In one embodiment, the second electrode 120 has a strip shape, is spaced apart from the first electrode 110 by a separator 130 interposed therebetween and extends in one direction, and includes a cathode coating region which is a region of a current collector of a metal foil (e.g., aluminum foil) coated with a cathode active material layer; and a cathode uncoated region which is a region where no active material is coated. The cathode uncoated region may be provided at an end portion in the extending direction of the second electrode 120.

[0042] The separator 130 extends in one direction between the first electrode 110 and the second electrode 120 to prevent or substantially prevent a short circuit between the first electrode 110 and the second electrode 120.

[0043] In one embodiment, the first electrode 110, the separator 130, and the second electrode 120 are sequentially stacked and wound into a jelly roll shape, but are not limited thereto, and may be formed into any of various known shapes. Each of the first electrode 110, the second electrode 120, and the separator 130 may include any of various known materials.

[0044] The first electrode tab 140 extends from the first electrode 110 of the electrode assembly 100 to the housing 200. The first electrode tab 140 is combined with the lower portion of the housing 200 to connect the first electrode 110 and the housing 200. The first electrode tab 140 is in contact with the first electrode 110 and the housing 200. In one embodiment, the first electrode tab 140 is welded to the lower portion of the housing 200, but is not limited thereto. Through the first electrode tab 140, the housing 200 has the same polarity as the first electrode 110.

[0045] The second electrode tab 150 extends from the second electrode 120 of the electrode assembly 100 to the terminal board 400. In one embodiment, the second electrode tab 150 is combined with the protrusion 420 of the terminal board 400 to connect the second electrode 120 and the terminal board 400. The second electrode tab 150 is in contact with the second electrode 120 and the terminal board 400. In one embodiment, the second electrode tab 150 is welded to the surface of the protrusion 420 of the terminal board 400, but is not limited thereto. Through the second electrode tab 150, the terminal board 400 has the same polarity as the second electrode 120.

[0046] In one embodiment, a center pin passing through the center of the electrode assembly 100 in the vertical direction is provided at the center portion of the electrode assembly 100, and the center pin can support the first electrode tab 140 and the second electrode tab 150, but is not limited thereto.

[0047] The housing 200 is connected to the first electrode 110 of the electrode assembly 100 and houses the electrode assembly 100. The housing 200 includes an opening 210 that exposes the upper portion of the electrode assembly 100. The lower portion of the housing 200 is connected to the first electrode 110 of the electrode assembly 100 through the first electrode tab 140 and has the same polarity as the first electrode 110. In one embodiment, the housing 200 is a cylindrical can that houses the jelly-roll-shaped electrode assembly 100, but is not limited thereto, and may have any of various known shapes. The housing 200 may house any of various known electrolyte solutions together with the electrode assembly 100. In one embodiment, the outer surface of the housing 200 may be the first electrode terminal of the rechargeable battery 1000, but is not limited thereto. In one embodiment, the upper surface of the flange portion 410, which is the outer surface of the terminal plate 400, may be the second electrode terminal of the rechargeable battery 1000, but is not limited thereto. In one embodiment, a plating may be coated on the outer surface of the housing 200, but the present invention is not limited thereto, and any of various known coatings may be coated on the outer surface of the housing 200.

[0048] The opening 210 of the housing 200 is covered by the cover plate 300 and the terminal plate 400.

[0049] The cover plate 300 is combined with the housing 200 to cover the peripheral area of the opening 210. The cover plate 3 includes a through hole 310 that exposes the central area of the opening 210. In one embodiment, the cover plate 300 is directly coupled to the side wall of the housing 200 that forms the opening 210 of the housing 200 through a welding process to cover the peripheral area of the opening 210. In one embodiment, the cover plate 300 has an annular shape through the through hole 310 formed in the center, but is not limited thereto. The cover plate 300 is combined with the housing 200 and has the same polarity as the first electrode 110. In one embodiment, the cover plate 300 includes stainless steel, but is not limited thereto, and may include a metal such as any one of aluminum, nickel, and copper. In one embodiment, the outer surface of the cover plate 300 may be the first electrode terminal of the rechargeable battery 1000, but is not limited thereto.

[0050] In one embodiment, a plating may be coated on the outer surface of the cover plate 300, but is not limited thereto, and any of various known coatings may be coated on the outer surface of the cover plate 300.

[0051] The terminal board 400 is connected to the second electrode 120 to be insulated from and bonded to the cover plate 300. The terminal board 400 covers the through hole 310 of the cover plate 300. The terminal board 400 is disposed on the cover plate 300. The terminal board 400 covers the central region of the opening 210 of the housing 200 exposed by the through hole 310 of the cover plate 300. In one embodiment, since the terminal board 400 covers the central region of the opening 210 and the cover plate 300 covers the peripheral region of the opening 210, the opening 210 of the housing 200 is completely covered by the terminal board 400 and the cover plate 300. The terminal board 400, together with the housing 200, the cover plate 300, and the thermal fusion layer 500, tightly seals the electrode assembly 100. The terminal board 400 is coupled to the second electrode tab 150 of the electrode assembly 100 to be connected to the second electrode 120 of the electrode assembly 100. The terminal board 400 has the same polarity as the second electrode 120.

[0052] The terminal board 400 includes a flange portion 410 and a protruding portion 420.

[0053] The flange portion 410 is disposed on the cover plate 300 and overlaps the cover plate 300 to cover the through hole 310. The flange portion 410 has a larger (wider) area than the protruding portion 420. The flange portion 410 may have a larger diameter than the protruding portion 420. In one embodiment, the upper surface of the flange portion 410 has a second diameter D2 that is smaller than the first diameter D1, which is the outer diameter of the housing 200, and larger than the third diameter D3, which is the outer diameter of the lower surface of the protruding portion 420. In one embodiment, the flange portion 410 has a thinner thickness than the protruding portion 420, but is not limited thereto. The lower surface of the flange portion 410 contacts the thermal fusion layer 500, and the flange portion 410 is insulatively bonded to the cover plate 300 through the thermal fusion layer 500. In one embodiment, the upper surface of the flange portion 410 may be the second electrode terminal of the rechargeable battery 1000.

[0054] The protrusion 420 protrudes from the flange portion 410 and passes through the through hole 310. The protrusion 420 is connected from the flange portion 410 through the through hole 310 to the second electrode 120. The lower surface of the protrusion 420 is bonded to the second electrode tab 150. In one embodiment, the lower surface of the protrusion 420 may be welded to the second electrode tab 150, but is not limited thereto. Since the protrusion 420 is combined with the second electrode tab 150, the protrusion 420 and the flange portion 410 of the terminal plate 400 have the same polarity as the second electrode 120. The lower surface of the protrusion 420 combined with the second electrode tab 150 may have a smaller diameter than the upper surface of the flange portion 410 that may be an electrode terminal. The lower surface of the protrusion 420 has a third diameter D3 as an outer diameter, and the third diameter D3 is smaller than the first diameter D1 that is the outer diameter of the housing 200 and the second diameter D2 that is the outer diameter of the upper surface of the flange portion 410. In one embodiment, the ratio of the third diameter D3 of the lower surface of the protrusion 420 to the second diameter D2 of the upper surface of the flange portion 410 is 1 / 10 to 1 / 3. That is, the third diameter D3 of the protrusion 420 / the second diameter D2 of the flange portion 410 is 1 / 10 to 1 / 3.

[0055] In one embodiment, the welding area of the second electrode tab 150 welded to the protrusion 420 is determined according to the ratio of the third diameter D3 of the protrusion 420 of the terminal plate 400 to the second diameter D2 of the flange portion 410. In one embodiment, since the ratio of the third diameter D3 of the protrusion 420 to the second diameter D2 of the flange portion 410 is 1 / 10 to 1 / 3, the second electrode tab 150 is firmly coupled to the protrusion 420.

[0056] In one embodiment, the protrusion 420 and the flange portion 410 are integrally formed, but are not limited thereto, and in another embodiment, different materials may be combined to form the terminal plate 400.

[0057] In one embodiment, a plating layer may be coated on the outer surface of the terminal plate 400, but is not limited thereto, and any of various known coatings may be coated on the outer surface of the terminal plate 400.

[0058] The thermal fusion layer 500 is disposed between the cover plate 300 and the flange portion 410 of the terminal plate 400 and is insulatingly bonded between the cover plate 300 and the flange portion 410 of the terminal plate 400. The thermal fusion layer 500 includes an insulating material and insulates between the cover plate 300 and the terminal plate 400. In one embodiment, the thermal fusion layer 500 is thermally fused between the cover plate 300 and the flange portion 410 of the terminal plate 410 by using heat or a laser beam. The thermal fusion layer 500 may include any of various known materials for insulating and bonding between the cover plate 300 and the terminal plate 400. By bonding the thermal fusion layer 500 between the cover plate 300 and the terminal plate 400, the opening 210 of the housing 200 in which the electrode assembly 100 is accommodated is completely sealed by the cover plate 300, the terminal plate 400, and the thermal fusion layer 500.

[0059] In one embodiment, the thermal fusion layer 500 is cured by heat but can be melted at a predetermined temperature. In one embodiment, the predetermined temperature at which the thermal fusion layer 500 melts may be a temperature exceeding the temperature for curing the thermal fusion layer 500, but is not limited thereto.

[0060] For example, the thermal fusion layer 500 may include a thermosetting resin and a thermoplastic resin. The thermosetting resin and the thermoplastic resin of the thermal fusion layer 500 may be laminated in multiple layers, but are not limited thereto. The thermosetting resin of the thermal fusion layer 500 is cured by heat and may include any of various known thermosetting resins, such as any one of phenolic resin, urea resin, melamine resin, epoxy resin, and polyester resin. In one embodiment, the thermoplastic resin of the thermal fusion layer 500 includes a polypropylene resin that melts at a predetermined temperature, but is not limited thereto, and may include any of various known thermoplastic resins, such as any one of polystyrene, polyethylene, and polyvinyl chloride resins.

[0061] The bonding area of the thermal fusion layer 500 that bonds the flange portion 410 and the cover plate 300 is determined according to the ratio of the third diameter D3 of the protrusion 420 of the terminal plate 400 to the second diameter D2 of the flange portion 410. In one embodiment, the ratio of the third diameter D3 of the protrusion 420 to the second diameter D2 of the flange portion 410 is 1 / 10 to 1 / 3, such that the flange portion 410 and the cover plate 300 are firmly bonded.

[0062] As described above, in the rechargeable battery 1000 according to the embodiment, the welding area of the second electrode tab 150 welded to the protruding portion 420 and the bonding area of the thermal fusion layer 500 that bonds the flange portion 410 to the cover plate 300 are determined according to the ratio of the third diameter D3 of the protruding portion 420 to the second diameter D2 of the flange portion 410. Moreover, since the ratio of the third diameter D3 of the protruding portion 420 to the second diameter D2 of the flange portion 410 is 1 / 10 to 1 / 3, the second electrode tab 150 is firmly coupled to the protruding portion 420, and the flange portion 410 and the cover plate 300 are firmly bonded together (e.g., simultaneously).

[0063] That is, since the ratio of the third diameter D3 of the protruding portion 420 to the second diameter D2 of the flange portion 410 is 1 / 10 to 1 / 3, a rechargeable battery 1000 is provided that includes a terminal plate 400 that is firmly sealed to the electrode assembly 100 together with the housing 200, the cover plate 300, and the thermal fusion layer 500 and is firmly connected to the second electrode tab 150 of the electrode assembly 100 (e.g., simultaneously).

[0064] Herein, reference Figure 3 describes experimental examples for confirming the effects of the rechargeable battery 1000 according to the embodiment described above.

[0065] Figure 3 is a table showing experimental examples demonstrating the effects of the rechargeable battery according to the embodiment.

[0066] In Figure 3 , the battery size may represent the outer diameter of the coin-type rechargeable battery, the housing specification may represent the specification of the housing of the rechargeable battery, and the terminal plate specification may represent the specification of the terminal plate.

[0067] Also, in Figure 3 , the housing diameter refers to Figure 2 the first diameter D1 of the housing 200 shown in Figure 2 , the flange diameter refers to Figure 2 the second diameter D2 of the flange portion 410 of the terminal plate 400 shown in Figure 2 , the protrusion diameter refers to Figure 2 the third diameter D3 of the protruding portion 420 of the terminal plate 400 shown in

[0068] Reference Figure 3, Experimental Examples 1 to 32 (1 to 32) were carried out to confirm the effects based on the numerical limits of the rechargeable battery according to the embodiments described above.

[0069] In Experimental Examples 1 to 4, the first diameter (housing diameter) of the housing was 8 mm, the second diameter (flange diameter) of the flange portion of the terminal plate was 6.8 mm, and the third diameter (boss diameter) of the protruding portion of the terminal plate was 0.5 mm to 2.5 mm.

[0070] In Experimental Example 1, the third diameter (boss diameter) of the protruding portion of the terminal plate was 0.5 mm, where the third diameter of the protruding portion / the second diameter of the flange portion was less than 1 / 10, and in this case, there was no abnormality (OK) in the bonding reliability confirmation result (leakage test result), but the welding reliability confirmation result (welding test result) was abnormal (NG).

[0071] In Experimental Example 2, the third diameter (boss diameter) of the protruding portion of the terminal plate was 0.7 mm, where the third diameter of the protruding portion / the second diameter of the flange portion was substantially 1 / 10, and in this case, there was no abnormality (OK) in both the bonding reliability confirmation result (leakage test result) and the welding reliability confirmation result (welding test result).

[0072] In Experimental Example 3, the third diameter (boss diameter) of the protruding portion of the terminal plate was 2.3 mm, where the third diameter of the protruding portion / the second diameter of the flange portion was substantially 1 / 3, and in this case, there was no abnormality (OK) in both the bonding reliability confirmation result (leakage test result) and the welding reliability confirmation result (welding test result).

[0073] In Experimental Example 4, the third diameter (boss diameter) of the protruding portion of the terminal plate was 2.5 mm, where the third diameter of the protruding portion / the second diameter of the flange portion exceeded 1 / 3, and in this case, there was no abnormality (OK) in the welding reliability confirmation result (welding test result), but there was an abnormality (NG) in the bonding reliability confirmation result (leakage test result).

[0074] As confirmed in Experimental Examples 2 and 3, when the ratio of the third diameter of the protruding portion to the second diameter of the flange portion was 1 / 10 to 1 / 3, the effect of firmly bonding the second electrode tab to the protruding portion and simultaneously (e.g., at the same time) firmly bonding the flange portion to the cover plate was confirmed.

[0075] In addition, as confirmed in Experimental Examples 1 and 4, when the ratio of the third diameter of the protruding portion to the second diameter of the flange portion was less than 1 / 10 or greater than 1 / 3, it was confirmed that the second electrode tab was not firmly attached to the protruding portion or the flange portion and the cover plate were not firmly bonded.

[0076] In other words, as a result confirmed in Experimental Examples 1 to 4, it was confirmed that the numerical limit of the ratio of the third diameter of the protrusion to the second diameter of the flange portion being 1 / 10 to 1 / 3 is the threshold range for achieving the effect that the second electrode tab is firmly bonded to the protrusion and the flange portion and the cover plate are firmly bonded together (e.g., simultaneously).

[0077] Further, as confirmed in Experimental Examples 5 to 32, when the ratio of the third diameter of the protrusion to the second diameter of the flange portion is 1 / 10 to 1 / 3, the effect that the second electrode tab is firmly bonded to the protrusion and the flange portion and the cover plate are firmly bonded together (e.g., simultaneously) is confirmed, and when the ratio of the third diameter of the protrusion to the second diameter of the flange portion is less than 1 / 10 or greater than 1 / 3, it is confirmed that the second electrode tab is not firmly bonded to the protrusion or the flange portion and the cover plate are not firmly bonded together.

[0078] In other words, as a result confirmed in Experimental Examples 5 to 32, it was confirmed that the numerical limit of the ratio of the third diameter of the protrusion to the second diameter of the flange portion being 1 / 10 to 1 / 3 is the threshold range for achieving the effect that the second electrode tab is firmly bonded to the protrusion and the flange portion and the cover plate are firmly bonded together (e.g., simultaneously).

[0079] Although the present invention has been described in connection with what are presently considered to be some possible exemplary embodiments, it should be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A rechargeable battery, comprising: An electrode assembly, comprising a first electrode, a second electrode, and a separator between the first electrode and the second electrode; A housing, connected to the first electrode, accommodating the electrode assembly, and comprising an opening for receiving the electrode assembly; A cover plate, coupled to the housing to cover a peripheral area of the opening, and comprising a through hole to expose a central area of the opening; And A terminal plate, connected to the second electrode to be insulated from and bonded to the cover plate, and comprising a flange portion covering the through hole and a protruding portion protruding from the flange portion and passing through the through hole, Wherein a ratio of a diameter of a bottom surface of the protruding portion to a diameter of the flange portion is from 1 / 10 to 1 / 3, Wherein the electrode assembly further comprises an electrode tab extending from the second electrode and welded to the bottom surface of the protruding portion of the terminal plate, Wherein the diameter of the bottom surface of the protruding portion is smaller than a diameter of the through hole, and Wherein the rechargeable battery further comprises a thermally fused layer between the cover plate and the flange portion to insulatively bond the cover plate and the flange portion, and the thermally fused layer is not provided in the through hole.

2. The rechargeable battery according to claim 1, wherein the thermally fused layer melts at a predetermined temperature.

3. The rechargeable battery according to claim 1, wherein The flange portion is disposed on the cover plate, and The protruding portion is connected to the second electrode from the flange portion through the through hole.

4. The rechargeable battery according to claim 3, wherein the electrode assembly further comprises: Another electrode tab extending from the first electrode and welded to the housing.

5. The rechargeable battery according to claim 1, wherein the flange portion has a wider area than the protruding portion.

6. The rechargeable battery according to claim 1, wherein the flange portion has a thinner thickness than the protruding portion.

7. The rechargeable battery according to claim 1, wherein the flange portion and the protruding portion are integrally formed.

8. The rechargeable battery according to claim 1, wherein The housing and the cover plate have the same polarity as the first electrode, and The terminal plate has the same polarity as the second electrode.

9. The rechargeable battery according to claim 1, wherein the diameter of the flange portion is smaller than a diameter of the housing.

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