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 including an internal space for accommodating the electrode assembly and including an opening; a cover plate coupled to the case at the opening and including a terminal hole exposing the internal space; an electrode terminal electrically connected to the electrode assembly, passing through the terminal hole, and overlapping the cover plate; electrode tabs respectively connected to the first electrode and the second electrode; and an electrolyte solution in the internal space, and at least one of the electrode tabs has an inclined portion that is inclined at a first angle with respect to a surface of the electrode assembly facing the at least one electrode tab.

Description

Technical Field

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

[0002] A rechargeable battery differs from a primary battery in that the rechargeable battery can be repeatedly charged and discharged, while the primary battery cannot be recharged. Low-capacity rechargeable batteries are used in portable electronic devices such as mobile phones, laptop computers, and camcorders, and high-capacity rechargeable batteries are widely used as power sources for driving motors of hybrid vehicles and the like.

[0003] As typical rechargeable batteries, there are nickel-cadmium (Ni-Cd) batteries, nickel-metal hydride (Ni-MH) batteries, lithium (Li) batteries, lithium-ion (Li-ion) rechargeable batteries, and the like. In particular, Li-ion rechargeable batteries have an operating voltage three times higher than that of Ni-Cd batteries and Ni-MH batteries, which are widely used as power sources for portable electronic devices. In addition, Li-ion rechargeable batteries have been widely used because of their high energy density per unit weight.

[0004] In particular, as the demand for wearable devices such as Bluetooth-enabled headsets, earbuds, smartwatches, and wearable medical devices increases, the demand for rechargeable batteries with high energy density and ultra-small size has increased.

[0005] The ultra-small rechargeable battery may include a coin single cell or a button single cell. Since the overall height of the coin single cell or the button single cell is low, the battery capacity may vary depending on its internal structure.

[0006] In addition, due to its ultra-small size, the electrolyte solution cannot be easily supplied to the electrode assembly.

[0007] The above information disclosed in this background art section is only for enhancing the understanding of the background of the present invention, and thus, it may include information that does not constitute the prior art known to those of ordinary skill in the art in this country. Summary of the Invention

[0008] According to an aspect of an embodiment of the present invention, there is provided an ultra-small rechargeable battery in which an electrolyte solution can easily flow into an electrode assembly.

[0009] 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 case including an internal space for accommodating the electrode assembly and including an opening; a cover plate coupled to the case at the opening and including a terminal hole exposing the internal space; an electrode terminal electrically connected to the electrode assembly, passing through the terminal hole, and overlapping the cover plate; electrode tabs respectively connected to the first electrode and the second electrode; and an electrolyte solution in the internal space, wherein at least one of the electrode tabs has an inclined portion that is inclined at a first angle with respect to a surface of the electrode assembly facing the at least one electrode tab.

[0010] The first angle may be 10 degrees or less.

[0011] The at least one electrode tab may further include a flat portion that extends from the inclined portion and is electrically connected to a bottom surface of the case or the electrode terminal.

[0012] The at least one electrode tab may include: a first electrode tab connecting the first electrode and the bottom surface of the case; and a second electrode tab connecting the second electrode and the electrode terminal, and the first electrode may be a negative electrode and the second electrode may be a positive electrode.

[0013] The inclined portion of the first electrode tab may be connected to the bottom surface of the case at a second angle, the inclined portion of the second electrode tab may be connected to a lower surface of the electrode terminal at a third angle, and the second angle and the third angle may be the same as the first angle.

[0014] The length of the at least one electrode tab may be greater than half of the diameter of the electrode assembly and less than the diameter of the electrode assembly.

[0015] The electrode assembly may further include a center pin at the center of the electrode assembly, and the flat portion may overlap the center pin.

[0016] The inclined portion and the flat portion may be connected to each other at an obtuse angle.

[0017] The electrode terminal may include: a flange portion covering the terminal hole and overlapping the cover plate; and a protrusion integrally formed with the flange portion and protruding from the flange portion toward the terminal hole.

[0018] The outer surface of the protrusion may have a curved surface and an inclined surface, and the distance from the curved surface to the edge of the terminal hole may be shorter than the distance from the inclined surface to the edge of the terminal hole, and the distance from the inclined surface to the edge of the terminal hole may become longer as it moves closer to the end of the inclined portion.

[0019] The rechargeable battery may further include a hot melt layer between the cover plate and the flange portion that insulatively bonds the cover plate and the flange portion.

[0020] The hot melt layer may melt at a predetermined temperature.

[0021] According to an aspect of an embodiment of the present invention, the electrode tab is inclinedly connected to the electrode assembly, so that since the electrode tab does not prevent the electrolyte solution from moving into the electrode assembly, the electrolyte solution can be easily supplied into the electrode assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a perspective view of a rechargeable battery according to an embodiment of the present invention.

[0023] Figure 2 is along Figure 1 sectional view taken along line II-II.

[0024] Figure 3 is a schematic diagram illustrating an electrode tab according to an embodiment of the present invention.

[0025] Figure 4 is Figure 2 enlarged view of region “A” of

[0026] Figure 5 is a sectional view of a rechargeable battery according to another embodiment of the present invention.

[0027] Figure 6 is Figure 5 enlarged view of region “B” of

[0028] REFERENCE SIGNS

[0029] 11: First electrode 12: Second electrode

[0030] 13: Separator 30: Step portion

[0031] 41: Flange portion 42: Protrusion

[0032] 100: Electrode assembly 200: Housing

[0033] 300: Cover plate 400: Electrode terminal

[0034] 500: Hot melt layer Detailed Implementation Modes

[0035] The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which some example embodiments of the present invention are shown. As will be recognized by those skilled in the art, the described embodiments may be modified in various different ways without departing from the scope of the present invention. The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals refer to like elements throughout the specification.

[0036] In addition, unless explicitly stated to the contrary, it should be understood that terms such as "including", "comprising", or "having" used in this specification specify 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.

[0037] Furthermore, 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 that other component, or connected or coupled to that other component with one or more other components intervening therebetween.

[0038] Unless the context clearly indicates otherwise, the singular forms will include the plural forms.

[0039] 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 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 example embodiments of the inventive concept. Unless the context clearly indicates otherwise, the singular form of a term may include the plural form.

[0040] In addition, terms such as "below", "under", "above", "over", etc. are used to describe the relationship of the configurations shown in the drawings. However, these terms are used as relative concepts and are described with reference to the directions indicated in the drawings.

[0041] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art 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 their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless explicitly so defined herein.

[0042] In this document, rechargeable batteries according to one or more embodiments will be described with reference to the accompanying drawings.

[0043] The rechargeable battery according to an embodiment of the present invention is an ultra-small rechargeable battery and may include a coin single cell or a button single cell, but the present invention is not limited thereto, and may include a cylindrical or pin-type single cell.

[0044] Here, the coin single cell or the button single cell is a thin coin-type or button-type single cell, and may refer to a battery having a height-to-diameter ratio (height / diameter) of 1 or less, but is not limited thereto.

[0045] In one embodiment, the coin single cell or the button single cell is cylindrical and has a circular horizontal cross-section, but the present invention is not limited thereto, and the horizontal cross-section may be oval or polygonal. In this case, the diameter may refer to the maximum distance of the single cell in the horizontal direction of the single cell, and the height may refer to the maximum distance of the single cell in the vertical direction of the single cell (the distance from the flat bottom surface of the single cell to the flat uppermost surface).

[0046] Figure 1 is a perspective view of a rechargeable battery according to an embodiment of the present invention; Figure 2 is along Figure 1 a cross-sectional view taken along line II-II; and Figure 3 is a schematic diagram illustrating an electrode tab according to an embodiment of the present invention.

[0047] See Figure 1 and Figure 2 Referring to

[0048] The rechargeable battery 1000 according to an embodiment of the present invention includes an electrode assembly 100, a housing 200 having an internal space for accommodating the electrode assembly 100, a cover plate 300 coupled to the housing 200 to seal the internal space, and an electrode terminal 400 passing through the cover plate to be electrically connected to the electrode assembly 100 and overlapping the cover plate.

[0049] The lower surface of the electrode assembly 100 faces the inner bottom surface of the housing 200, and the upper surface of the electrode assembly 100 faces the lower surface of the cover plate 300 covering the opening 21 of the housing 200.

[0050] The first electrode 11 includes an electrode active region and an electrode uncoated region. The electrode active region is a region where the active material is applied to a thin plate formed of a long strip of metal foil, and the electrode uncoated region is a region where the active material is not applied; and the first electrode tab 14 can be connected to the electrode uncoated region.

[0051] The uncoated regions of the electrodes may be respectively formed at opposite ends of the electrode active region, i.e., corresponding ends of the first electrode 11 in its longitudinal direction, but are not limited thereto, and in one embodiment, may be formed only at one end. In one embodiment, the first electrode 11 may be a negative electrode, and in the electrode active region, an active material such as graphite or carbon may be coated on a metal foil such as copper or nickel.

[0052] In one embodiment, the first electrode tab 14 is electrically connected to the uncoated region of the first electrode 11 of the electrode assembly 100 and protrudes to the outside of the electrode assembly 100 to be welded to the bottom surface of the housing 200, thereby electrically connecting the first electrode 11 to the housing 200. Accordingly, the housing 200 connected to the first electrode 11 by the first electrode tab 14 has the same polarity as the first electrode 11.

[0053] See Figure 3 , in one embodiment, the length of the first electrode tab 14 may be longer than half of the diameter of the electrode assembly 100, or longer than the radius of the electrode assembly 100, and may be shorter than the diameter, so that the first electrode tab 14 may facilitate the welding process and will not wrinkle.

[0054] In one embodiment, the first electrode tab 14 may have an inclined portion 4 that is inclined and connected to the electrode assembly 100 at an angle of 10 degrees or less. That is, the surface of the inclined portion 4 facing the electrode assembly 100 may have a first angle θ1 of 10 degrees or less with respect to the lower surface of the electrode assembly 100. In this case, the lower surface of the electrode assembly 100 is a virtual horizontal surface, and the end of the protruding film is located on this horizontal surface, and this horizontal surface is parallel to the inner surface of the housing 200.

[0055] The first electrode tab 14 may have a flat portion 5 that extends from the inclined portion 4 and is attached to the bottom surface of the housing 200. In one embodiment, the surface of the flat portion 5 is parallel to and attached to the bottom surface of the housing 200, and the inclined portion 4 may be connected to the bottom surface of the housing 200 at a second angle θ2. In one embodiment, the second angle θ2 may be the same as the first angle θ1.

[0056] The flat portion 5 may be connected to the inclined portion 4 at an obtuse angle, and in one embodiment, the flat portion 5 may be pressed by a center pin 50.

[0057] As described above, when the first electrode tab 14 is provided with the inclined portion 4 that is inclined and connected to the electrode assembly 100, a space S is formed between the electrode assembly 100 and the inclined portion, so that the electrolyte solution may not be blocked by the first electrode tab 14 and may easily flow into the electrode assembly 100.

[0058] The second electrode 12 includes an electrode active region and an electrode uncoated region. The electrode active region is the region where the active material is applied to a thin plate formed of a strip-shaped metal foil, and the electrode uncoated region is the region where the active material is not applied; and the second electrode tab 15 can be connected to the electrode uncoated region.

[0059] The electrode uncoated regions can be respectively formed at opposite ends of the electrode active region, i.e., the corresponding ends of the second electrode 12 in its length direction, but are not limited thereto, and in one embodiment, can be formed at only one end.

[0060] The second electrode tab 15 can be connected to the electrode uncoated region of the second electrode 12, and the second electrode tab 15 can protrude from the second electrode 12 to be electrically connected to the electrode terminal 400. The second electrode tab 15 can be made of a conductive material such as nickel or copper and can be connected to the electrode uncoated region by welding. In one embodiment, the welding can be laser welding.

[0061] In one embodiment, the second electrode 12 can be a positive electrode, and in the electrode active region, an active material such as a transition metal oxide can be coated on a metal foil such as aluminum.

[0062] The second electrode tab 15 is electrically connected to the electrode uncoated region of the second electrode 12 of the electrode assembly 100 and protrudes to the outside of the electrode assembly 100 to be welded to the lower surface of the electrode terminal 400, thereby electrically connecting the second electrode 12 to the electrode terminal 400. Through the second electrode tab 15, the electrode terminal 400 has the same polarity as the second electrode 12.

[0063] In one embodiment, the length of the second electrode tab 15 can be longer than half of the diameter of the electrode assembly 100, or longer than the radius of the electrode assembly 100, and can be shorter than the diameter, so that the second electrode tab 15 can facilitate the welding process and will not wrinkle. After the second electrode tab 15 is fixed to the electrode terminal 400 by welding, the cover plate 300 can be welded to the housing 200.

[0064] In one embodiment, the second electrode tab 15 can have an inclined portion 7 connected to the electrode assembly 100 at an angle of 10 degrees or less. That is, the surface of the inclined portion 7 facing the electrode assembly 100 can have a first angle θ1 of 10 degrees or less with respect to the upper surface of the electrode assembly 100. In this case, the upper surface of the electrode assembly 100 is a virtual horizontal surface, and the end of the protruding film is located on this horizontal surface, and this horizontal surface is parallel to the inner surface of the cover plate 300. In one embodiment, at least one of the first electrode tab 14 and the second electrode tab 15 can include an inclined portion that is inclined at the first angle θ1 with respect to the surface of the electrode assembly 100 facing the at least one electrode tab.

[0065] The second electrode tab 15 may have a flat portion 8 extending from the inclined portion 7 and attached to the lower surface of the protrusion of the electrode terminal 400. In one embodiment, the surface of the flat portion 8 is parallelly attached to the lower surface of the electrode terminal 400, and the inclined portion 7 may be connected to the lower surface of the electrode terminal 400 at a third angle θ3. In one embodiment, the third angle θ3 may be the same as the first angle θ1.

[0066] In one embodiment, the flat portion 8 may be pressed by the center pin 50. The flat portion 8 may be connected to the inclined portion 7 at an obtuse angle.

[0067] As described above, when the second electrode tab 15 is provided with the inclined portion 7 inclinedly connected to the electrode assembly 100, the electrode assembly 100 is spaced apart from the inclined portion by a space S, so that the electrolyte solution may not be obstructed by the second electrode tab 15 and may easily flow into the electrode assembly 100.

[0068] Return to refer Figure 1 and Figure 2 , the separator 13 is located between the first electrode 11 and the second electrode 12 to prevent or substantially prevent a short circuit between the first electrode 11 and the second electrode 12 and allow the movement of lithium ions. The separator 13 may be made of, for example, any one of polyethylene, polypropylene, and a composite film of polyethylene and polypropylene.

[0069] In one embodiment, the width of the separator 13 may be equal to or greater than the width of the first electrode 11 or the second electrode 12, and the width of the first electrode 11 may be greater than the width of the second electrode 12. In this case, the width is the length in the direction along which the electrode assembly 100 is inserted into the housing.

[0070] The electrode assembly 100 may have a jelly roll shape in which the first electrode 11, the separator 13, and the second electrode 12 overlap and are wound around a rotation axis, but is not limited thereto, and may have a structure (not shown) in which the first electrode, the separator, and the second electrode in sheet form are repeatedly stacked.

[0071] In one embodiment, the electrode assembly 100 may be covered with an insulating tape (not shown) along the outer peripheral surface in the diameter direction. The insulating tape electrically insulates the outer peripheral surface of the electrode assembly 100 from the inner surface of the housing 200 while protecting the outside of the electrode assembly 100.

[0072] The electrode assembly 100 may be accommodated in the housing 200 together with the electrolyte solution in a direction parallel to the rotation axis of the electrode assembly 100. The electrolyte solution may be composed of an organic solvent such as any one of EC, PC, DEC, and EMC and a Li salt such as LiPF6 and LiBF4. The electrolyte solution may be in a liquid state, a solid state, or a gel state.

[0073] The central pin 50 passing through the center of the electrode assembly 100 in the vertical direction can be located at the center of the electrode assembly 100, and the central pin 50 can support the first electrode tab 14 and the second electrode tab 15. In one embodiment, the diameter of the central pin 50 can be approximately 1.2 mm.

[0074] The housing 200 has a space for accommodating the electrode assembly 100 and the electrolyte solution, and an opening 21 on one side thereof is open. The electrode assembly 100 can be inserted through the opening 21 to be accommodated in the inner space of the housing 200. The housing 200 can have a low-height cylindrical shape, but is not limited thereto, and can have any of various known shapes. The housing 200 can accommodate any of various known electrolyte solutions and the electrode assembly 100, and in one embodiment, can be made of stainless steel.

[0075] The inner bottom surface of the housing 200 is connected to the first electrode 11 of the electrode assembly 100 through the first electrode tab 14, so that the housing 200 has the same polarity as the first electrode 11.

[0076] The outer surface of the housing 200 can be the first electrode terminal of the rechargeable battery 1000, and the outer surface of the electrode terminal 400 can be the second electrode terminal of the rechargeable battery 1000.

[0077] The cover plate 300 closes and seals the inner space of the housing 200, the electrode terminal 400 can be coupled to the opening 21 of the housing 200, and the cover plate 300 can be coupled to the opening 21 by welding.

[0078] The cover plate 300 can be formed to have a shape corresponding to the opening 21, and a stepped portion 30 can be formed in the opening 21, so that the cover plate 300 can be easily installed.

[0079] A terminal hole 31 is formed in the center of the cover plate 300, and the terminal hole 31 corresponds to the center of the electrode assembly 100 to expose the upper part of the electrode assembly 100. The cover plate 300 can have an annular shape due to the terminal hole 31 formed in its center.

[0080] The cover plate 300 is coupled to the housing 200 and has the same polarity as the first electrode 11, and the outer surface of the cover plate 300 can be the first electrode terminal of the rechargeable battery 1000. In one embodiment, the cover plate 300 includes stainless steel, but is not limited thereto, and can include metals such as aluminum, nickel, or copper.

[0081] The electrode terminal 400 is insulated from and bonded to the cover plate 300 having a polarity different from that of the electrode terminal 400, and can be electrically connected to the second electrode 12 of the electrode assembly 100 through the terminal hole 31 of the cover plate 300. Therefore, the electrode terminal 400 can be the second electrode terminal of the rechargeable battery 1000.

[0082] In one embodiment, the electrode terminal 400 may include stainless steel, but is not limited thereto, and may include metals such as aluminum, nickel, or copper.

[0083] In one embodiment, the housing 200 and the cover plate 300 may be connected to the first electrode 11 serving as the negative electrode, so that the first electrode terminal can be the negative terminal, and the electrode terminal 400 may be electrically connected to the second electrode 12 serving as the positive electrode, so that the second electrode terminal can be the positive terminal.

[0084] In one embodiment, the housing 200 and the cover plate 300 may be made of the same material.

[0085] The electrode terminal 400 may include a flange portion 41 and a protrusion 42. The flange portion 41 may have a wider area (or diameter) than the protrusion 42, and the flange portion 41 has a thinner thickness than the protrusion 42. The protrusion 42 and the flange portion 41 may be integrally formed.

[0086] The protrusion 42 of the electrode terminal 400 is inserted into the terminal hole 31 and, together with the flange portion 41, covers the terminal hole 31 of the cover plate 300 to seal the interior of the housing 200. The protrusion 42 of the electrode terminal 400 is electrically connected to the second electrode tab 15 of the electrode assembly 100, so that the electrode terminal 400 has the same polarity as the second electrode 12. The outer surface of the flange portion 41 can be the second electrode terminal of the rechargeable battery 1000.

[0087] Figure 4 For Figure 2 the enlarged view of area “A”.

[0088] See Figure 4 , in one embodiment, the outer surface of the protrusion 42 includes a curved surface CS and an inclined surface IS. The protrusion 42 includes the curved surface CS extending from the lower surface of the flange portion 41 and the inclined surface IS extending from the curved surface CS to pass through the terminal hole 31.

[0089] The curved surface CS may have a radius of curvature (e.g., a predetermined radius of curvature), and the inclined surface IS may have a slope (e.g., a predetermined slope). Accordingly, as the surface of the protrusion 42 advances from the curved surface CS toward the end of the inclined surface IS, it moves further away from the edge of the terminal hole 31. As described above, when the inclined surface IS is formed, the distance in the horizontal direction between the cover plate 300 and the protrusion 42 of the electrode terminal 400 increases, so that even if an alignment error occurs, a short circuit between the cover plate 300 and the protrusion 42 having different polarities can be avoided.

[0090] Return to Figure 1 and Figure 2 , the lower surface of the flange portion 41 of the electrode terminal 400 may be attached to the surface of the cover plate 300 through the heat-melting layer 500. Since the cover plate 300 and the electrode terminal 400 are bonded by the heat-melting layer 500, the opening 21 of the housing 200 accommodating the electrode assembly 100 is completely sealed by the cover plate 300, the electrode terminal 400, and the heat-melting layer 500.

[0091] The heat-melting layer 500 is heat-melted and bonded between the cover plate 300 and the flange portion 41 of the electrode terminal 400 by heat or a laser beam.

[0092] The heat-melting layer 500 is made of an insulating material to insulate the electrode terminal 400 from the cover plate 300. The heat-melting layer 500 may include any one of various known materials that insulatively bond the cover plate 300 and the electrode terminal 400.

[0093] In one embodiment, the heat-melting layer 500 is cured by heat but can be melted at a predetermined temperature. In one embodiment, the predetermined temperature at which the heat-melting layer 500 melts may be a temperature higher than the temperature of the heat used to cure the heat-melting layer 500, but is not limited thereto.

[0094] For example, the heat-melting layer 500 may include a thermosetting resin and a thermoplastic resin. The thermosetting resin and the thermoplastic resin of the heat-melting layer 500 may be stacked in multiple layers, but are not limited thereto. The thermosetting resin of the heat-melting layer 500 is in a state of being cured by heat and may include any one of various known thermosetting resins, such as phenol resin, urea resin, melamine resin, epoxy resin, and polyester resin. In one embodiment, the thermoplastic resin of the heat-melting layer 500 includes a polypropylene resin that melts at a predetermined temperature, but is not limited thereto, and may include any one of various known thermoplastic resins, such as polystyrene, polyethylene, and polyvinyl chloride resins.

[0095] As described above, in one embodiment, the heat-melting layer 500 melts at a predetermined temperature, and a portion of the heat-melting layer 500 that is removed becomes a ventilation channel through which gas is discharged.

[0096] When an accident (e.g., a short circuit between two electrodes) occurs in the internal space of the rechargeable battery 1000, the temperature increases, the heat-melting layer 500 melts due to the increased temperature, and its volume decreases, thereby forming a ventilation channel through which the gas GA generated inside the rechargeable battery is discharged to the outside. The internal gas is guided from the internal space of the rechargeable battery 1000 along the curved surface CS of the electrode terminal 400 to the space between the flange portion 41 and the cover plate 300 (this space is the ventilation channel) to be quickly discharged to the outside, thereby suppressing the explosion risk of the rechargeable battery 1000.

[0097] Figure 5 is a cross-sectional view of a rechargeable battery according to another embodiment of the present invention; and Figure 6 is Figure 5 an enlarged view of region "B" of

[0098] In Figure 5 and Figure 6 the rechargeable battery 1002 according to an embodiment of the present invention shown in Figures 1 to 3 is substantially the same as the rechargeable battery shown in

[0099] See Figure 5 and Figure 6 The rechargeable battery 1002 according to an embodiment of the present invention includes an electrode assembly 100, a housing 200, a cover plate 300, an electrode terminal 400, and a heat-melting layer 500.

[0100] The electrode assembly 100 includes a first electrode 11, a second electrode 12, and a separator 13, and the first electrode 11 can be electrically connected to the bottom surface of the housing 200 through a first electrode tab 14.

[0101] The first electrode tab 14 may have an inclined portion and a flat portion, such as Figure 3 the inclined portion 4 and the flat portion 5 shown in

[0102] The inclined portion can be inclined and connected to the virtual lower horizontal surface of the electrode assembly 100 at an angle of 10 degrees or less, and the flat portion can be connected to the bottom surface of the housing 200. The flat portion can be pressed by a center pin 50. The length of the first electrode tab 14 can be longer than half of the diameter of the electrode assembly 100, or longer than the radius of the electrode assembly 100, and can be shorter than the diameter, so that the first electrode tab 14 can facilitate the welding process and will not wrinkle.

[0103] The electrode terminal 400 covers the central area of the opening 21 of the housing 200 that is exposed by the terminal hole 31 of the cover plate 300. The electrode terminal 400 covers the central area of the opening 21, and the cover plate 300 covers the outer area of the opening 21. Therefore, the opening 21 of the housing 200 is completely sealed by the electrode terminal 400 and the cover plate 300. The electrode terminal 400 is connected to the second electrode tab 15 of the electrode assembly 100 to be electrically connected to the second electrode 12 of the electrode assembly 100.

[0104] The second electrode tab 15 may have an inclined portion 7 and a flat portion 8. The inclined portion 7 may be inclined and connected to the virtual upper horizontal surface of the electrode assembly 100 at an angle of 10 degrees or less, and the flat portion 8 may be connected to the electrode terminal 400. The flat portion 8 may be pressed by the center pin 50. The length of the second electrode tab 15 may be longer than half of the diameter of the electrode assembly 100 or longer than the radius of the electrode assembly 100 and may be shorter than the diameter, so that the second electrode tab 15 can facilitate the welding process and will not wrinkle.

[0105] The electrode terminal 400 includes a flange portion 41 and a protrusion 42. The flange portion 41 is located between the cover plate 300 and the electrode assembly 100 in the housing 200 and overlaps with the cover plate 300 to cover the terminal hole 31.

[0106] The upper surface of the flange portion 41 contacts the heat-melt layer 500, and the flange portion 41 is insulatingly bonded to the cover plate 300 through the heat-melt layer 500. The lower surface of the flange portion 41 is electrically connected to the second electrode tab 15. Since the flange portion 41 is connected to the second electrode tab 15, the protrusion 42 and the flange portion 41 of the electrode terminal 400 have the same polarity as the second electrode 12.

[0107] The protrusion 42 passes through the terminal hole 31 to be exposed to the outside of the housing 200. The outer surface of the protrusion 42 may be the second electrode terminal of the rechargeable battery 1002.

[0108] The outer surface of the protrusion 42 may be in the same plane or a different plane as the outer surface of the cover plate 300. For example, the height of the outer surface of the protrusion 42 may be the same as the height of the outer surface of the cover plate 300, but is not limited thereto, and the height of the outer surface of the protrusion 42 may be higher or lower than the height of the outer surface of the cover plate 300.

[0109] In one embodiment, the outer surface of the protrusion 42 includes a curved surface CS and an inclined surface IS.

[0110] The protrusion 42 includes a curved surface CS extending from the upper surface of the flange portion 41 and an inclined surface IS extending from the curved surface CS to pass through the terminal hole 31.

[0111] The curved surface CS may have a radius of curvature (e.g., a predetermined radius of curvature), and the inclined surface IS may have a slope (e.g., a predetermined slope). Accordingly, as the surface of the protrusion 42 advances from the curved surface CS toward the end of the inclined surface IS, the surface of the protrusion 42 moves further away from the edge of the terminal hole 31. As described above, when the inclined surface IS is formed, the distance in the horizontal direction between the cover plate 300 and the protrusion 42 of the electrode terminal 400 increases, so that even if an alignment error occurs, a short circuit between the cover plate 300 and the protrusion 42 having different polarities can be avoided.

[0112] As described above, when the flange portion 41 is connected within the housing 200 through the heat-melting layer 500, and when the temperature within the housing 200 increases due to the occurrence of an event and the heat-melting layer 500 melts, the flange portion 41 separates from the cover plate 300 and moves in the direction of gravity, so that the terminal hole 31 can be opened. Thus, compared with the Figure 1 embodiment, an explosion can be prevented or substantially prevented by discharging the internal gas to the outside more quickly.

[0113] Although the present invention has been described in connection with some presently considered practical embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but on the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

Claims

1. A rechargeable battery, comprising: An electrode assembly, including a first electrode, a second electrode, and a separator between the first electrode and the second electrode; A housing, including an internal space for accommodating the electrode assembly and including an opening; A cover plate, coupled to the housing at the opening and including a terminal hole exposing the internal space; An electrode terminal, electrically connected to the electrode assembly, the electrode terminal including a flange portion overlapping the cover plate and a protrusion protruding from the flange portion and passing through the terminal hole; Electrode tabs, respectively connected to the first electrode and the second electrode; And An electrolyte solution in the internal space, Wherein at least one of the electrode tabs includes an inclined portion and a flat portion, the inclined portion being inclined at a first angle with respect to a surface of the electrode assembly facing the at least one electrode tab, the flat portion extending from the inclined portion and being electrically connected to a bottom surface of the housing or the electrode terminal, and a surface of the flat portion being parallelly attached to the bottom surface of the housing or the electrode terminal; and Wherein the inclined portion is located in a space between the cover plate and a surface of the electrode assembly facing the cover plate and / or between a bottom surface of the housing and a surface of the electrode assembly facing the bottom surface of the housing; Wherein the protrusion includes: A curved surface extending from the flange portion; and An inclined surface extending from the curved surface, the inclined surface being inclined such that a distance from the inclined surface to an edge of the terminal hole becomes longer as it approaches an end of the inclined portion.

2. The rechargeable battery according to claim 1, wherein the first angle is 10 degrees or less.

3. The rechargeable battery according to claim 1, wherein the at least one electrode tab includes: A first electrode tab connecting the first electrode and the bottom surface of the housing; And A second electrode tab connecting the second electrode and the electrode terminal, and The first electrode is a negative electrode and the second electrode is a positive electrode.

4. The rechargeable battery according to claim 3, wherein The inclined portion of the first electrode tab is connected to the bottom surface of the housing at a second angle, The inclined portion of the second electrode tab is connected to a lower surface of the electrode terminal at a third angle, and The second angle and the third angle are the same as the first angle.

5. The rechargeable battery according to claim 1, wherein a length of the at least one electrode tab is greater than half of a diameter of the electrode assembly and less than the diameter of the electrode assembly.

6. The rechargeable battery according to claim 1, wherein The electrode assembly further includes a center pin at a center of the electrode assembly, and The flat portion overlaps the center pin.

7. The rechargeable battery according to claim 1, wherein the inclined portion and the flat portion are connected to each other at an obtuse angle.

8. The rechargeable battery according to claim 1, wherein, The flange portion covers the terminal hole; and The protrusion is integrally formed with the flange portion.

9. The rechargeable battery according to claim 8, wherein the distance from the curved surface to the edge of the terminal hole is shorter than the distance from the inclined surface to the edge of the terminal hole.

10. The rechargeable battery according to claim 8, further comprising a hot melt layer between the cover plate and the flange portion and insulatingly bonding the cover plate and the flange portion.

11. The rechargeable battery according to claim 10, wherein the hot melt layer melts at a predetermined temperature.

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