Secondary battery

Abstract

The secondary battery includes: an electrode assembly including a positive electrode and a negative electrode; a case accommodating the electrode assembly; and a cover assembly covering the housing. The cover assembly includes: a cover plate covering an opening of the housing and including a terminal hole; the gasket is arranged on the cover plate around the terminal hole; and a rivet inserted into the terminal hole, coupled to the cover plate through the gasket, and including a first protrusion inserted into an upper portion of the gasket.

Description

Technical Field

[0001] Embodiments of the present application relate to a secondary battery, and more particularly, to a secondary battery including a housing and an electrode assembly. Background Art

[0002] Secondary batteries are batteries that can be repeatedly charged and discharged. With the development of the information communications and display industries, they are widely used as power sources for portable electronic communication devices such as cameras, mobile phones, and laptop computers. Furthermore, in recent years, battery packs containing secondary batteries have also been developed and used as power sources for environmentally friendly vehicles such as electric vehicles.

[0003] Secondary batteries include lithium secondary batteries, nickel-cadmium batteries, and nickel-metal hydride batteries. Among them, lithium secondary batteries have advantages in charging speed and light weight due to their high operating voltage and energy density per unit weight, and therefore are being actively researched and developed.

[0004] A secondary battery may include an electrode assembly including a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode. The electrode assembly is housed together with an electrolyte in an outer casing such as a pouch, a circular casing, or a prismatic casing, thereby defining a battery cell.

[0005] The case may include a terminal for supplying current to the electrode assembly. In a terminal coupling structure connecting the terminal and the electrode assembly, chemical and mechanical defects may be induced through interfaces of components. Summary of the Invention

[0006] (1) Technical issues to be resolved

[0007] A technical problem of the present disclosure is to provide a secondary battery with improved mechanical stability and operational reliability.

[0008] (2) Technical solution

[0009] A secondary battery according to an embodiment of the present disclosure includes an electrode assembly including a positive electrode and a negative electrode; a housing housing the electrode assembly; and a cap assembly covering the housing. The cap assembly includes a cap plate covering the housing and including a terminal hole; a gasket disposed on the cap plate around the terminal hole; and a rivet inserted into the terminal hole, coupled to the cap plate via the gasket, and including a first protrusion inserted into an upper portion of the gasket.

[0010] In some embodiments, the rivet may include: a rivet body inserted into the terminal hole; and rivet wings extending from the rivet body in a horizontal direction, and the first protrusion may extend downward from a bottom surface of the rivet wing.

[0011] In some embodiments, the separation distance between the first protrusion and the rivet body may be greater than 30% of the length of the rivet wing.

[0012] In some embodiments, the washer may include: a vertical extension portion contacting a side surface of the rivet body; and a washer wing extending from the vertical extension portion along the horizontal direction. The first protrusion may be inserted into an upper portion of the washer wing.

[0013] In some embodiments, the cover plate may include a second protrusion that is inserted into a lower portion of the gasket wing.

[0014] In some embodiments, the second protrusion may extend upward from the top surface of the cover plate.

[0015] In some embodiments, a plurality of the first protrusions and a plurality of the second protrusions may be inserted into the gasket wings.

[0016] In some embodiments, the first protrusions and the second protrusions may be alternately arranged along the horizontal direction.

[0017] In some embodiments, any one of the second protrusions may overlap with two or more first protrusions in a vertical direction.

[0018] In some embodiments, a separation distance from a distal side of the gasket wing to the second protrusion may be greater than 15% of a length of the gasket wing.

[0019] In some embodiments, the cap assembly may further include an upper insulating portion disposed on the cap plate and partially covering the gasket wing.

[0020] In some embodiments, the cap assembly may further include a lower insulating portion disposed below the cap plate and in contact with the vertically extending portion of the gasket.

[0021] A secondary battery includes an electrode assembly comprising a positive electrode and a negative electrode; a housing housing the electrode assembly; and a cap assembly covering the housing. The cap assembly includes a cap plate covering the housing and including a terminal hole; a gasket disposed on the cap plate around the terminal hole and including a vertically extending portion and a gasket wing bent horizontally from the vertically extending portion; and a rivet coupled to the cap plate via the gasket and including a rivet body inserted into the terminal hole and a rivet wing extending horizontally from the rivet body, the rivet wing or the cap plate including a protrusion fastened to the gasket wing.

[0022] In some embodiments, the washer wing may be sandwiched between the rivet wing and the cover plate.

[0023] In some embodiments, the vertical extension and the gasket wing may be a unitary component.

[0024] In some embodiments, the protrusion may include a first protrusion that protrudes downward from a bottom surface of the rivet wing.

[0025] In some embodiments, the protrusion may include a second protrusion protruding upward from the top surface of the cover plate.

[0026] In some embodiments, the housing may be a prismatic housing.

[0027] In some embodiments, the cap assembly may further include a terminal plate disposed on the rivet.

[0028] (3) Beneficial effects

[0029] According to the above embodiment, the gasket and the rivet of the cap assembly of the secondary battery can each include a wing portion extending in the horizontal direction, thereby increasing the bonding stability between the gasket and the rivet while effectively blocking the inflow of foreign matter and leakage of electrolyte.

[0030] According to an embodiment of the present disclosure, the rivet wing may include a protrusion that inserts into the upper portion of the washer wing. In some embodiments, the cover plate of the cap assembly may include a protrusion that inserts into the lower portion of the washer wing. The protrusion can more effectively prevent electrolyte leakage and improve the stability of the terminal joint structure.

[0031] Secondary batteries manufactured using the disclosed electrolyte injection device can be widely used in green technology fields such as battery-powered electric vehicles, battery charging stations, and solar and wind power generation. Furthermore, these secondary batteries can be used in eco-friendly electric vehicles and hybrid vehicles, which aim to prevent climate change by suppressing air pollution and greenhouse gas emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic perspective view illustrating a secondary battery according to an exemplary embodiment.

[0033] Figure 2 is a schematic partial cross-sectional view illustrating a secondary battery according to an exemplary embodiment.

[0034] Figure 3 and Figure 4 is a partially enlarged cross-sectional view illustrating a terminal coupling structure of a cap assembly according to an exemplary embodiment.

[0035] Figure 5 and Figure 6 is a partially enlarged cross-sectional view illustrating a terminal coupling structure of a cap assembly according to an exemplary embodiment.

[0036] Figure 7 and Figure 8 is a partially enlarged cross-sectional view of a terminal coupling structure of a cap assembly according to an exemplary embodiment.

[0037] Figures 9 to 11 is a partially enlarged cross-sectional view of a terminal coupling structure of a cap assembly according to an exemplary embodiment. DETAILED DESCRIPTION

[0038] The exemplary embodiments provided by the present disclosure will be described in more detail below with reference to the accompanying drawings. However, the drawings and embodiments of this specification are intended to help better understand the technical ideas of the present disclosure, and the present disclosure should not be limited to the contents described in the drawings and embodiments.

[0039] In this specification, terms indicating space / position, such as “lower,” “upper,” “below,” and “upper,” are used as relative concepts to distinguish components, and do not limit an absolute order or position.

[0040] The term "connection" used in this specification includes the case where two different components are directly connected, as well as the case where they are indirectly connected via an intermediate component.

[0041] Figure 1 is a schematic perspective view illustrating a secondary battery according to an exemplary embodiment. Figure 2 is a schematic partial cross-sectional view showing a secondary battery according to an exemplary embodiment. For example, Figure 2 It is along Figure 1 A partial cross-sectional view taken along line II' in the third direction.

[0042] exist Figure 1 and Figure 2 , the first direction, the second direction, and the third direction may be the length direction, the width direction, and the height direction of the secondary battery or the housing 110, respectively. The directions opposite to the directions indicated by the arrows may also be considered to be the same directions. The above definitions of directions are substantially the same and apply to the remaining figures.

[0043] Reference Figure 1 and Figure 2 , the secondary battery 100 may include a case 110 and an electrode assembly 50 accommodated in the case 110 .

[0044] like Figure 1As shown, for example, the housing 110 may have a prismatic shape with a hexagonal column form. However, the form of the housing 110 can be appropriately changed in consideration of the application object of the secondary battery, the required capacity / power, etc. For example, the housing 110 may also have a cylindrical shape, a coin shape, etc.

[0045] The housing 110 may include a first side surface 110a and a second side surface 110b that face each other in the first direction. The housing 110 may include a first front surface 110c and a second front surface 110d that face each other in the second direction. The housing 110 includes a bottom surface 110e at one end in the third direction, and the cover assembly 190 may be coupled or assembled to the upper part of the housing 110 in the third direction. The cover assembly 190 may enclose or seal the upper part of the housing 110.

[0046] The electrode assembly 50 may include a positive electrode 70 and a negative electrode 60 that are repeatedly stacked. In some embodiments, the positive electrode 70 and the negative electrode 60 may be alternately and repeatedly stacked along the third direction with a separator 80 interposed therebetween.

[0047] The positive electrode 70 may include a positive electrode current collector 75 and a positive electrode active material layer 72 coated on the surface of the positive electrode current collector 75 (for example, the top surface and the bottom surface in the third direction). The positive electrode current collector 75 may include stainless steel, nickel, aluminum, titanium, or an alloy thereof. [[ID=~]]

[0048] The positive electrode active material layer 72 may include a lithium-containing positive electrode active material, and the secondary battery

[0033] may be provided as a lithium secondary battery.

[0049] The lithium-containing positive electrode active material may include lithium nickel oxide, lithium cobalt oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium iron phosphate-based compounds, lithium nickel aluminum-based oxides, lithium cobalt aluminum-based oxides, etc.

[0050] The negative electrode 60 may include a negative electrode current collector 65 and a negative electrode active material layer 62 coated on the surface of the negative electrode current collector 65 (for example, the top surface and the bottom surface in the third direction). The negative electrode current collector 65 may include copper, stainless steel, nickel, titanium, or an alloy thereof.

[0051] The negative electrode active material layer 62 may include carbon-based active materials such as natural graphite and artificial graphite as the negative electrode active material and / or silicon-containing active materials (for example, SiOx (0 < x < 2)). The negative electrode active material may also include a silicon-carbon composite material.

[0052] The separator 80 may comprise a porous polymer film made of polyolefin-based polymers such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer. The separator 80 may also comprise a non-woven fabric formed of high-melting-point glass fiber, polyethylene terephthalate fiber, or the like.

[0053] The separator 80 may also include a ceramic-based material. For example, inorganic particles may be coated on or dispersed within the polymer film to improve heat resistance.

[0054] By winding, stacking, Z-folding, etc. the separator 80, the positive electrode 70 and the negative electrode 60 can be repeatedly and alternately stacked with the separator 80 therebetween to form the electrode assembly 50. In one embodiment, the electrode assembly 50 can be manufactured in a jelly roll form.

[0055] One end of the positive electrode collector 75 included in the positive electrode 70 of each layer can serve as the positive electrode tab 77 . One end of the negative electrode collector 65 included in the negative electrode 60 of each layer can serve as the negative electrode tab 67 .

[0056] The positive electrode tabs 77 may protrude and gather toward one side in the first direction (e.g., adjacent to the second side 110 b ) and be connected to the positive electrode lead 92 . The negative electrode tabs 67 may protrude and gather toward the other side in the first direction (e.g., adjacent to the first side 110 a ) and be connected to the negative electrode lead 95 .

[0057] In some embodiments, the positive electrode tabs 77 may be welded together and then connected to the positive electrode lead 92. In one embodiment, the positive electrode tabs 77 may be welded together with the positive electrode lead 92. In some embodiments, the negative electrode tabs 67 may be welded together and then connected to the negative electrode lead 95. In one embodiment, the negative electrode tabs 67 may be welded together with the negative electrode lead 95.

[0058] exist Figure 2 , the positive electrode 70 and the negative electrode 60 are stacked in the third direction and connected to the electrode leads on both sides in the first direction. However, the stacking direction of the positive electrode 70 and the negative electrode 60 and the connection position of the electrode leads can be appropriately changed according to the size of the housing 110 and the required capacity / power.

[0059] In some embodiments, the electrode assembly 50 may be housed together with an electrolyte in the case 110. A non-aqueous electrolyte may be used as the electrolyte.

[0060] The non-aqueous electrolyte includes a lithium salt as an electrolyte and an organic solvent. For example, the lithium salt can be Li + X - For example, as the anion of the lithium salt (X- ), we can exemplify F - 、Cl - Br - , I - 、NO3 - 、N(CN)2 - 、BF4 - 、ClO4 - PF6 - 、(CF3)2PF4 - 、(CF3)3PF3 - 、(CF3)4PF2 - 、(CF3)5PF - 、(CF3)6P - CF3SO3 - CF3CF2SO3 - 、(CF3SO2)2N - 、(FSO2)2N - CF3CF2(CF3)2CO - 、(CF3SO2)2CH - 、(SF5)3C - 、(CF3SO2)3C - CF3(CF2)7SO3 - CF3CO2 - 、CH3CO2 - 、SCN - 、(CF3CF2SO2)2N - wait.

[0061] Examples of the organic solvent include propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), methylpropyl carbonate, dipropyl carbonate, dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, vinylene carbonate, sulfolane, γ-butyrolactone, propylene sulfite, and tetrahydrofuran. These can be used alone or in combination of two or more.

[0062] Electrode leads (positive lead 92 and negative lead 95) may be connected to electrode terminal portions 112 and 115, respectively, included in cap assembly 190. Positive lead 92 may be connected to positive terminal portion 112, and negative lead 95 may be connected to negative terminal portion 115.

[0063] The cap assembly 190 may include a cap plate 180 exposed to the outside of the secondary battery 100 , and the cap plate 180 may seal the case 110 accommodating the electrode assembly 50 .

[0064] The cap plate 180 may further include a vent portion 183 and an electrolyte injection portion 181. The vent portion 183 and the electrolyte injection portion 181 may include a vent hole and an electrolyte injection hole, respectively, and may include a plug or a plate sealing the vent hole and the electrolyte injection hole.

[0065] The vent portion 183 and the electrolyte injection portion 181 may be formed between the positive terminal portion 112 and the negative terminal portion 115 .

[0066] The electrode terminal portions 112 and 115 may be formed with a terminal coupling structure electrically connected or coupled to the electrode leads 92 and 95. The composition and structure of the cap assembly 190 and the terminal coupling structure will be described in more detail below.

[0067] Figure 3 and Figure 4 is a schematic partial enlarged cross-sectional view showing a terminal coupling structure of a cover assembly according to an exemplary embodiment. For example, Figure 3 It is along Figure 1 The II' line is a cross-sectional view of the terminal coupling structure cut along the third direction. Figure 4 yes Figure 3 A partial enlarged cross-sectional view of area A.

[0068] Reference Figure 3 The terminal coupling structure included in the cap assembly 190 may include a terminal plate 130, an upper insulating portion 140, a rivet 150, and a washer 160. The terminal plate 130 may be exposed to the outside of the secondary battery 100 and provided as an actual external terminal. The terminal column 120 may be inserted into the center portion of the terminal plate 130.

[0069] The upper insulating portion 140 may include an insulating material such as a resin material. The upper insulating portion 140 may be provided on the top surface of the cover plate 180 to support and fix the lower portion of the terminal plate 130. The upper insulating portion 140 may insulate the terminal plate 130 and the cover plate 180 from each other.

[0070] The rivet 150 may pass through and be inserted into the terminal plate 130 and the upper insulating portion 140. The upper portion of the rivet 150 may contact or engage with the terminal post 120. The terminal plate 130 and the upper insulating portion 140 may be welded or fastened to the cap assembly 190 through the upper portion of the rivet 150.

[0071] The terminal plate 130 , the terminal post 120 , and the rivet 150 may include conductive materials such as metal or alloy.

[0072] The gasket 160 can fix the rivet 150 to the cover plate 180. The gasket 160 can seal the space between the cover plate 180 and the rivet 150. The gasket 160 can include an insulating resin material such as perfluoroalkoxy resin (PFA).

[0073] The cap plate 180 may include a terminal hole 182. A washer 160 may be provided on the cap plate 180 around the terminal hole 182. The rivet 150 may be inserted into the terminal hole 182.

[0074] The terminal coupling structure can be electrically connected to the electrode leads 92 and 95 via the lead terminals 170. A lower insulating portion 175 can be provided on the bottom surface of the cover plate 180 to insulate the lead terminals 170 from the cover plate 180. The lower insulating portion 175 can include a resin material substantially the same as or similar to that of the upper insulating portion 140.

[0075] Reference Figure 4 The rivet 150 may include a rivet body 150a and a rivet wing 150b. The washer 160 may include a vertical extension 160a and a washer wing 160b.

[0076] The rivet body 150a may extend in a vertical direction (e.g., the third direction) and may refer to a portion that passes through the terminal plate 130 and the cover plate 180. The rivet wing 150b may refer to a portion that extends from the upper portion of the rivet body 150a in a horizontal direction (e.g., the first direction). The rivet wing 150b and the rivet body 150a may be an integral component.

[0077] The vertical extension 160a of the washer 160 may extend in the third direction and may contact the side of the rivet body 150a. The vertical extension 160a may also contact the sidewalls of the cover plate 180 and the lower insulating portion 175. The washer wing 160b may refer to a portion that bends or expands horizontally (e.g., the first direction) from the upper portion of the vertical extension 160a. The washer wing 160b and the vertical extension 160a may be an integral component.

[0078] The washer wing 160b may be sandwiched between the rivet wing 150b and the cap plate 180. According to an exemplary embodiment, the rivet wing 150b may be seated on the washer wing 160b. The rivet wing 150b may contact the top surface of the washer wing 160b and may be fastened to the cap plate 180 and the terminal plate 130. Therefore, the rivet 150 may be stably fixed to the electrode terminal portions 112 and 115.

[0079] In addition, the vertical extension portion 160a may contact the cap plate 180 and the lower insulating portion 175 and may surround the side of the rivet body 150a. Therefore, the riveting stability may be further improved.

[0080] According to an embodiment of the present disclosure, the rivet wing 150b may include a first protrusion 155. The first protrusion 155 may extend from a bottom surface of the rivet wing 150b and may be inserted into an upper portion of the washer wing 160b.

[0081] The first protrusion 155 may be integrally connected to the rivet wing 150b and may extend below the top surface of the washer wing 160b in the third direction. The washer wing 160b may include a first groove for inserting the first protrusion 155.

[0082] According to the above embodiment, the welding stability or bonding stability of the rivet 150 and the washer 160 can be further enhanced by the first protrusion 155. Therefore, the inflow of foreign matter into the electrode terminal parts 112 and 115 and the leakage of the electrolyte contained in the case 110 can be prevented.

[0083] The first protrusion 155 can press the gasket wing 160 b downward from above, thereby effectively preventing leakage of electrolyte from occurring at the interface between the gasket 160 and the cap plate 180 .

[0084] The upper insulating portion 140 may be formed on the cap plate 180 and partially cover the gasket wing 160b. The upper insulating portion 140 may cover a portion of the gasket wing 160b that protrudes horizontally from a side surface of the rivet wing 150b.

[0085] Figure 5 and Figure 6 is a partially enlarged cross-sectional view illustrating a terminal coupling structure of a cap assembly according to an exemplary embodiment. Figure 6 yes Figure 5 The combination of rivets, washers and cover plates ( Figure 3 A magnified cross-sectional view of region B).

[0086] Reference Figure 5 , the cover plate 180 may include a second protrusion 185. The second protrusion 185 may extend from the top surface of the cover plate 180 and may be inserted into the bottom of the gasket wing 160b.

[0087] The second protrusion 185 may be integrally connected to the cover plate 180 and may extend in the third direction above the bottom surface of the gasket wing 160b. The gasket wing 160b may include a second groove for inserting the second protrusion 185.

[0088] According to the above embodiment, the welding stability or bonding stability of the gasket 160 and the cap plate 180 can be further enhanced by the second protrusion 185. Therefore, the inflow of foreign matter into the electrode terminal parts 112 and 115 and the leakage of the electrolyte contained in the case 110 can be more effectively prevented.

[0089] In some embodiments, the first and second protrusions 155 and 185 can compress the gasket wing 160b from two directions. Furthermore, the first and second protrusions 155 and 185 can function as teeth or screws to secure the gasket wing 160b. This improves riveting stability while effectively preventing electrolyte leakage at the interface between the gasket 160 and the cover plate 180.

[0090] Reference Figure 6 The spacing distance W2 between the first protrusion 155 and the rivet body 150a may be about 30% or more of the length W1 of the rivet wing 150b. The spacing distance W2 of the first protrusion 155 may be the shortest distance from the side of the rivet body 150a to the sidewall of the first protrusion 155 in the first direction.

[0091] In some embodiments, the separation distance W2 of the first protrusion 155 may be greater than about 40%, greater than about 50%, or greater than about 60% of the length W1 of the rivet wing 150 b. In one embodiment, the separation distance W2 of the first protrusion 155 may be 40% to 90%, 50% to 90%, 55% to 85%, or 60% to 80% of the length W1 of the rivet wing 150 b.

[0092] Within the separation distance range, the electrolyte can be effectively blocked by the first protrusion 155 and the gasket wing 160 b can be pressed.

[0093] In some embodiments, the distance L2 from the side of the gasket wing 160b to the second protrusion 185 may be about 15% or more of the length L1 of the gasket wing 160b. For example, the distance L2 from the second protrusion 185 may be the shortest distance from the side of the distal end of the gasket wing 160b to the sidewall of the second protrusion 185 in the first direction.

[0094] In some embodiments, the separation distance L2 of the second protrusion 185 may be greater than or equal to about 20%, greater than or equal to about 30%, greater than or equal to about 40%, or greater than or equal to about 50% of the length L1 (length in the first direction) of the gasket wing 160 b. In one embodiment, the separation distance L2 of the second protrusion 185 may be between 20% and 90%, between 30% and 90%, between 40% and 80%, or between 50% and 80% of the length L1 of the gasket wing 160 b.

[0095] Within the separation distance range, the electrolyte can be effectively blocked by the second protrusion 185 and the gasket wing 160 b can be pressed.

[0096] In some embodiments, the height of the first protrusion 155 (the height in the third direction) may be 0.1 mm to 1 mm. In one embodiment, the height of the first protrusion 155 may be 0.1 mm to 0.5 mm. In one embodiment, the height of the first protrusion 155 may be 0.1 mm to 0.4 mm or 0.1 mm to 0.3 mm.

[0097] In some embodiments, the height of the second protrusion 185 (the height in the third direction) may be 0.1 mm to 1 mm. In one embodiment, the height of the second protrusion 185 may be 0.1 mm to 0.5 mm. In one embodiment, the height of the second protrusion 185 may be 0.1 mm to 0.4 mm or 0.1 mm to 0.3 mm.

[0098] Within the height range of the protrusion, sufficient compression force can be transmitted to the gasket wing 160 b while preventing the gasket wing 160 b from being mechanically damaged.

[0099] Figure 7 and Figure 8 is a partially enlarged cross-sectional view illustrating a terminal coupling structure according to an exemplary embodiment.

[0100] Reference Figure 7 , the rivet wing 150 b may include a plurality of first protrusions 155 . In some embodiments, the cover plate 180 may also include a plurality of second protrusions 185 .

[0101] A plurality of first protrusions 155 may be arranged along the first direction and may contact an upper portion of the gasket wing 160b. A plurality of second protrusions 185 may be arranged along the first direction and may contact a lower portion of the gasket wing 160b.

[0102] In some embodiments, the first protrusions 155 and the second protrusions 185 may be alternately and repeatedly arranged along the first direction. Thus, the screw connection of the washer wing 160 b can be substantially achieved by the protrusions 155 and 185 .

[0103] Reference Figure 8 , the rivet wing 150 b may include a plurality of first protrusions 155 . In some embodiments, the cover plate 180 may also include a plurality of second protrusions 185 .

[0104] Any one of the second protrusions 185 may overlap with two or more first protrusions 155 in the height direction (third direction). In one embodiment, at least another one of the second protrusions 185 may not overlap with the first protrusion 155 in the height direction.

[0105] As described above, by making the arrangement of the protrusions 155 and 185 irregular, the possibility of electrolyte leakage can be further reduced.

[0106] Figures 9 to 11 is a partially enlarged cross-sectional view illustrating a terminal coupling structure of a cap assembly according to an exemplary embodiment. Figures 9 to 11 yes Figure 3 Enlarged cross-sectional view of area B.

[0107] Reference Figure 9 , the protrusions 155, 185 may have a trapezoidal shape. In some embodiments, the first protrusion 155 and the second protrusion 185 may have mutually inverted trapezoidal shapes.

[0108] Reference Figure 10 , the protrusions 155, 185 may have a triangular shape. In some embodiments, the first protrusion 155 and the second protrusion 185 may have mutually inverted triangular shapes.

[0109] Reference Figure 11 The protrusions 155 and 185 may have a curved shape, for example, a semicircular shape. In some embodiments, the first protrusion 155 and the second protrusion 185 may have mutually inverted semicircular shapes.

[0110] The shapes of the protrusions 155 and 185 may be appropriately modified in consideration of preventing electrolyte leakage and ensuring terminal connection stability.

Claims

1. A secondary battery comprising: an electrode assembly, including a positive electrode and a negative electrode; a housing for accommodating the electrode assembly; as well as a cover assembly covering the housing, The cover assembly comprises: a cover plate covering the housing and comprising a terminal hole; a gasket disposed on the cover plate around the terminal hole; and A rivet is inserted into the terminal hole, coupled to the cap plate through the washer, and includes a first protrusion inserted into an upper portion of the washer.

2. The secondary battery according to claim 1, wherein The rivet comprises: a rivet body inserted into the terminal hole; and Rivet wings, extending horizontally from the rivet body, The first protrusion extends downward from a bottom surface of the rivet wing.

3. The secondary battery according to claim 2, wherein A separation distance between the first protrusion and the rivet body is greater than or equal to 30% of a length of the rivet wing.

4. The secondary battery according to claim 2, wherein The gasket comprises: a vertical extension in contact with a side surface of the rivet body; and a washer wing extending from the vertical extension along the horizontal direction, The first protrusion is inserted into the upper portion of the gasket wing.

5. The secondary battery according to claim 4, wherein The cover plate includes a second protrusion that is inserted into a lower portion of the gasket wing.

6. The secondary battery according to claim 5, wherein The second protrusion extends upward from the top surface of the cover plate.

7. The secondary battery according to claim 5, wherein The first plurality of protrusions and the second plurality of protrusions are inserted into the gasket wings.

8. The secondary battery according to claim 7, wherein The first protrusions and the second protrusions are alternately arranged along the horizontal direction.

9. The secondary battery according to claim 7, wherein Any one of the second protrusions overlaps with two or more first protrusions in a vertical direction.

10. The secondary battery according to claim 5, wherein The distance between the second protrusion and the distal end side of the gasket wing is greater than or equal to 15% of the length of the gasket wing.

11. The secondary battery according to claim 4, wherein The cap assembly further includes an upper insulating portion disposed on the cap plate and partially covering the gasket wing.

12. The secondary battery according to claim 4, wherein The cap assembly further includes a lower insulating portion disposed below the cap plate and in contact with the vertically extending portion of the gasket.

13. A secondary battery comprising: an electrode assembly, including a positive electrode and a negative electrode; a housing for accommodating the electrode assembly; as well as a cover assembly covering the housing, The cover assembly comprises: a cover plate covering the housing and comprising a terminal hole; a washer provided on the cover plate around the terminal hole and comprising a vertically extending portion and a washer wing bent in a horizontal direction from the vertically extending portion; and a rivet coupled to the cover plate through the washer and comprising a rivet body inserted into the terminal hole and rivet wings extending from the rivet body in a horizontal direction, The rivet wing or the cover plate includes a protrusion fastened to the washer wing.

14. The secondary battery according to claim 13, wherein The washer wing is sandwiched between the rivet wing and the cover plate.

15. The secondary battery according to claim 13, wherein The vertical extension and the gasket wing are a unitary component.

16. The secondary battery according to claim 13, wherein The protrusion includes a first protrusion that protrudes downward from a bottom surface of the rivet wing.

17. The secondary battery according to claim 13, wherein The protrusion includes a second protrusion that protrudes upward from a top surface of the cover plate.

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