Button-type secondary battery

Abstract

The present invention relates to a button-type secondary battery which is capable of collecting gas generated in the battery to prevent the battery from being deteriorated due to gas pressure or to prevent a gas harmful to a human body from escaping from the battery, and is capable of preventing electrolyte from leaking outside the battery, even if gas generated in the battery produces excessive internal pressure. The button-type secondary battery according to the present invention is a button-type secondary battery having a shape in which the length of its diameter is greater than its height, the secondary battery including: an electrode assembly; a lower can into which the electrode assembly is inserted; and an upper can covering an upper opening of the lower can, wherein an inwardly recessed crimped portion is provided in an upper portion of the lower can, and an end portion of the upper can has a curved shape, and the upper can and the lower can are coupled to each other while an end point of the end portion of the upper can is inserted into the crimped portion.

Description

Technical Field

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2020-0119500, filed on September 16, 2020, and Korean Patent Application No. 10-2021-0109102, filed on August 18, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0004] This invention relates to a button-type secondary battery, and more specifically, to a button-type secondary battery that can collect the gas inside the battery even when the gas generated in the battery creates excessive internal pressure, in order to prevent the battery from being disassembled or to prevent harmful gases from leaking to the outside of the battery due to gas pressure, and to prevent electrolyte from leaking to the outside of the battery. Background Technology

[0005] In recent years, due to the consumption of fossil fuels, rising energy prices, increased concern about environmental pollution, and the growing demand for environmentally friendly alternative energy sources, the future of life is becoming increasingly important. Therefore, research into various power generation technologies such as solar, wind, and tidal power is ongoing, and energy storage devices such as batteries are receiving significant attention for the more efficient use of generated electricity.

[0006] Furthermore, with technological advancements and the increasing demand for battery-powered electronic mobile devices and electric vehicles, the demand for batteries as an energy source is rapidly increasing. Therefore, much research has been conducted on batteries capable of meeting diverse needs.

[0007] In particular, there is a high demand for lithium secondary batteries (such as lithium-ion batteries and lithium-ion polymer batteries) with advantages such as high energy density, discharge voltage and output stability, in terms of materials.

[0008] Secondary batteries are classified according to the shape of their casings into cylindrical batteries and prismatic batteries (where the electrode assembly is embedded in a cylindrical or prismatic metal can) and pouch batteries (where the electrode assembly is embedded in a pouch-shaped casing made of aluminum laminate). Furthermore, recently, due to the trend towards smaller wearable devices, the importance of developing small batteries such as button-type secondary batteries has been highlighted.

[0009] Figure 1 It is a cross-sectional view of a button-type secondary battery based on existing technology.

[0010] Reference Figure 1According to the prior art, the button-shaped secondary battery 10 has a shape divided into an upper casing and a lower casing, and has a press-fit structure of a cylindrical upper can 4 and a cylindrical lower can 3. That is, the outer diameter of the cylindrical lower can 3 is slightly larger than the outer diameter of its upper part to achieve press-fit. In the case of press-fit, the principle is that the shape of the button-shaped secondary battery is maintained by the friction generated by press-fit. Furthermore, in the button-shaped secondary battery according to the prior art, the upper can 4 and the lower can 3 are manufactured to match the size of the internal electrode assembly 1 so as to press-fit each other, therefore, there is no usable space therein.

[0011] However, in this configuration, when the internal pressure increases due to the generation of internal gases, there is no retaining force other than friction. Therefore, the upper tank 4 and the lower tank 3 are highly likely to separate from each other. If the internal pressure rises, it may increase due to side reactions and also during normal cycling. However, if the internal pressure rises excessively, the upper and lower tanks will separate from each other, thus failing to function as a battery.

[0012] Therefore, there is a need for batteries that can collect gases generated by internal reactions within the battery, and there is also a need to study products where the upper and lower canisters are not separated from each other.

[0013] Furthermore, the button-type secondary battery 10 according to the prior art has a structure with a high probability of electrolyte leakage. That is, since the leakage path of electrolyte leakage is simple, the probability of electrolyte leakage is high, and therefore many studies have been carried out to solve this problem. Summary of the Invention

[0014] Technical issues

[0015] The present invention was designed to solve the above problems, and the purpose of the present invention is to collect the gas inside the battery even if the gas generated in the battery generates excessive internal pressure, thereby preventing the battery from being disassembled, or preventing harmful gases from leaking to the outside of the battery due to gas pressure, and preventing electrolyte from leaking to the outside of the battery.

[0016] Technical solution

[0017] According to the present invention, a button-type secondary battery has a diameter greater than its height, the button-type secondary battery comprising: an electrode assembly; a lower can into which the electrode assembly is inserted; and an upper can configured to cover an opening at the upper end of the lower can, wherein an inwardly recessed rolled edge portion is provided in the upper portion of the lower can, and the end of the upper can has a curved shape such that the upper can and the lower can can be connected to each other, while the end point of the upper can is inserted into the rolled edge portion.

[0018] A collection space for collecting internal gases can be provided between the upper tank and the electrode assembly.

[0019] The upper can may include: an upper can electrode terminal portion connected to an electrode of the electrode assembly to form a terminal and configured to cover an opening at the upper end of the lower can; a first bent portion bent to extend from an end of the upper can electrode terminal portion toward the bottom surface of the lower can; and a second bent portion bent to extend from an end of the first bent portion in the direction of the central axis of the lower can and disposed within the rolled edge portion.

[0020] The lower can may include a vertical upper portion, which is bent to extend from the end of the rolled edge portion toward the electrode terminal portion of the upper can.

[0021] The vertical portion at the upper end of the lower tank and the first curved portion can extend in parallel directions and be positioned facing each other.

[0022] The button-type secondary battery may also include an insulator configured to prevent the upper and lower cans from contacting each other.

[0023] The insulator can be made of polybutylene terephthalate (PBT) material.

[0024] The insulator may include: a first insulator portion that fills the space surrounded by the top surface of the rolled edge portion, the upper vertical portion of the lower can, and the upper electrode terminal portion; a second insulator portion that extends from the first insulator portion and fills the space formed between the first curved portion and the upper vertical portion of the lower can; and a third insulator portion that extends from the second insulator portion and fills the space formed between the second curved portion and the rolled edge portion.

[0025] A central hole may be formed at the center of the electrode assembly, and a central pin may be disposed in the central hole to completely fill the central hole.

[0026] The button-type secondary battery may also include an electrode connector configured to connect the electrodes of the electrode assembly to the upper can electrode terminal portion.

[0027] One end of the electrode connector can be connected to the electrode of the electrode assembly, and

[0028] The other end of the electrode connector is connected in a C-shape to the bottom surface of the upper can electrode terminal portion.

[0029] The upper can may further include an upper can protrusion that protrudes toward the insulator from at least one of the upper can electrode terminal portion, the first bent portion, or the second bent portion.

[0030] The lower can may further include a lower can protrusion that protrudes toward the insulator from at least one of the rolled edge portion or the upper vertical portion of the lower can.

[0031] Methyl orange pH tablets can be attached to the outer wall of the lower tank.

[0032] Beneficial effects

[0033] The button-type secondary battery according to the present invention relates to a button-type secondary battery having a diameter greater than its height, and comprising a lower can and an upper can, wherein an electrode assembly is inserted into the lower can, and the upper can covers an opening at the upper end of the lower can, wherein an inwardly recessed rolled edge portion may be provided in the upper end of the lower can. The end of the upper can may have a curved shape such that the upper and lower cans are connected to each other, with the end point of the upper can inserted into the rolled edge portion. Therefore, even if excessive internal pressure is generated due to gas produced inside the battery, the gas inside the battery can be collected to prevent the battery from being disassembled or to prevent harmful gases from leaking to the outside of the battery due to gas pressure, and to prevent electrolyte leakage to the outside of the battery. Attached Figure Description

[0034] Figure 1 It is a cross-sectional view of a button-type secondary battery based on existing technology.

[0035] Figure 2 This is a cross-sectional view of a button-type secondary battery according to Embodiment 1 of the present invention.

[0036] Figure 3 yes Figure 2 An enlarged cross-sectional view of region A.

[0037] Figure 4 In the button-type secondary battery according to Embodiment 2 of the present invention Figure 2 A cross-sectional view of region A. Detailed Implementation

[0038] Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings, enabling those skilled in the art to readily practice the invention. However, the invention may be implemented in several different forms and is not limited to or construed as follows.

[0039] To clearly explain the invention, detailed descriptions of relevant known technologies that are irrelevant to the description or may unnecessarily obscure the essence of the invention have been omitted, and reference numerals have been added to components in each drawing throughout this specification. In this case, the same or similar reference numerals are assigned to the same or similar elements throughout the specification.

[0040] Furthermore, the terms or words used in this specification and claims should not be construed as having a general meaning or dictionary-based meaning, but should be interpreted as meanings and concepts that are within the scope of the invention, based on the principle that the inventor can appropriately define the concepts of the terms in order to best describe and interpret his or her invention.

[0041] Implementation Method 1

[0042] Figure 2 This is a cross-sectional view of a button-type secondary battery according to Embodiment 1 of the present invention.

[0043] Reference Figure 2 According to Embodiment 1 of the present invention, the button-type secondary battery 100 may be a battery with a cylindrical shape, wherein the diameter of the cylindrical battery may be greater than the height of the battery. Furthermore, the button-type secondary battery 100 according to Embodiment 1 of the present invention may include an electrode assembly 150, a lower can 110, and an upper can 130. The electrode assembly 150 may have an alternating stacked shape of electrodes 151 and separators 152 wound together.

[0044] Furthermore, the electrode assembly 150 can be inserted into the lower can 110. The lower can 110 may have a cylindrical opening at the upper end. The electrode assembly 150 may be in the form of a jelly roll. When the electrode assembly 150 is placed in the lower can 110, the winding axis of the electrode assembly 150 may be arranged perpendicular to the ground. The upper can 130 may be plate-shaped or stepped plate-shaped. Furthermore, the upper can 130 may have an opening that covers the upper end of the lower can 110.

[0045] A recessed rolled edge portion 111 may be provided on the upper part of the lower can 110. The rolled edge portion 111 may be formed along the entire periphery of the outer peripheral surface of the lower can 110. For example... Figure 2 As shown, the rolled edge portion 111 may have a cross-sectional shape that is recessed at a 90-degree angle, or it may have a shape that is recessed in the form of a curved surface, unlike the figure shown.

[0046] In the button-type secondary battery 100 according to Embodiment 1 of the present invention, the end of the upper can 130 is bent, and the upper can 130 and the lower can 110 are connected to each other, while the end point 134 of the upper can is inserted into the rolled edge portion 111.

[0047] An insulator 170 may also be provided to prevent the upper can 130 and the lower can 110 from contacting each other. In particular, the portion between the curved end of the upper can 130 and the upper end of the lower can 110 may be a portion where the upper can 130 and the lower can 110 are directly connected to each other. Therefore, the insulator 170 may be configured to be inserted into this portion.

[0048] The end of the upper can 130 can be bent or curled in a bent shape. In the bent shape, the upper end can be press-fitted into the curled edge portion 111. The upper end can press-fit the upper end of the lower can 110, including the curled edge portion 111, and the insulator 170 together. Because the upper can 130 and the lower can 110 are connected to each other by applying pressure, the upper can 130 and the lower can 110 are not easily separated from each other, but are firmly connected to each other.

[0049] Therefore, even if the gas generated inside the battery creates excessive internal pressure, the battery will not be disassembled due to this pressure, and the harmful gases inside the battery will not leak to the outside.

[0050] Here, the insulator 170 can be made of polybutylene terephthalate (PBT). PBT material can have good mechanical properties, especially high rigidity, to achieve batteries with excellent hermeticity and durability.

[0051] In the button-type secondary battery 100 according to Embodiment 1 of the present invention, the upper can 130 may include an upper can electrode terminal portion 133, a first bent portion 131, and a second bent portion 132. The upper can electrode terminal portion 133 refers to the portion that forms a terminal by connecting to the electrode 151 of the electrode assembly 150, and may be the portion that covers the opening at the upper end of the lower can 110. The upper can electrode terminal portion 133 may be a terminal for connecting an external device to the secondary battery according to the present invention. Furthermore, the upper can electrode terminal portion 133 may be a positive terminal.

[0052] Furthermore, the first bent portion 131 of the upper can 130 may be bent to extend from the end of the upper can electrode terminal portion 133 toward the bottom surface 114 of the lower can. The second bent portion 132 may be bent to extend from the end of the first bent portion 131 in the direction of the central axis of the lower can 110. Moreover, the second bent portion 132 may be disposed inside the crimped portion 111. Since the second bent portion 132 is connected to the interior of the crimped portion 111 while being pressed into it, separation of the upper can 130 and the lower can 110 may not be easily achieved.

[0053] In the button-type secondary battery 100 according to Embodiment 1 of the present invention, the lower can 110 may include an upper vertical portion 113, which is bent to extend from the end of the rolled edge portion 111 toward the upper can electrode terminal portion 133. The upper vertical portion 113 may be bent upward in the vertical direction from the upper end of the rolled edge portion 111. However, it does not necessarily have to be bent in the vertical direction, and the upward extension toward the upper can electrode terminal portion 133 should be considered to be within the scope of the present invention. Here, the upper vertical portion 113 of the lower can and the first bent portion 131 of the upper can 130 may extend in directions parallel to each other, but may be arranged to face each other.

[0054] In the button-type secondary battery 100 according to Embodiment 1 of the present invention, a collection space 120 for collecting internal gas is provided between the upper canister 130 and the electrode assembly 150. More specifically, the collection space 120, as a space for collecting gas, may be provided between the upper canister electrode terminal portion 133 and the electrode assembly 150. When internal gas is generated due to side reactions of the battery, since the gas is a light gas, it rises to fill the collection space 120.

[0055] The collection space 120 between the upper canister 130 and the electrode assembly 150 is a usable space for gas collection to prevent gas leakage outside the battery (since no holes are formed in the upper canister 130, gas will not be discharged to the outside through the upper canister 130). Due to the characteristics of batteries used in wearable electronic devices, if gas leaks outside the battery, it is harmful to the human body, and therefore, gas must be managed to prevent leakage to the outside of the battery. For this purpose, the button-type secondary battery 100 according to the invention can achieve the management objective.

[0056] In the button-type secondary battery 100 according to Embodiment 1 of the present invention, the insulator 170 may include a first insulator portion 171, a second insulator portion 172 and a third insulator portion 173.

[0057] Reference Figure 2 and Figure 3 The first insulating portion 171 may be the portion filling the space surrounded by the top surface 112 of the rolled edge portion, the upper vertical portion 113 of the lower can, and the upper electrode terminal portion 133 of the upper can. The second insulating portion 172 may be the portion extending from the first insulating portion 171 and filling the space formed between the first curved portion 131 and the upper vertical portion 113 of the lower can. The third insulating portion 173 may be the portion extending from the second insulating portion 172 and filling the space formed between the second curved portion 132 and the rolled edge portion 111.

[0058] Furthermore, the combined shape of the cross-sections of the first insulator portion 171, the second insulator portion 172, and the third insulator portion 173 can be a rectangular shape as a whole. That is, as... Figure 3 As shown, the insulator 170 has a rectangular shape overall, and the curved portions of the upper can 130, the upper vertical portion 113 of the lower can, and the rolled edge portion 111 are embedded in the rectangular shape in a maze-like shape.

[0059] In this configuration, an insulator 170 comprising a first insulator portion, a second insulator portion, and a third insulator portion is inserted, and the first curved portion 131 and the second curved portion 132 of the upper can 130, which are press-fitted and bent, the rolled edge portion 111 of the lower can 110 having an inwardly curved and concave shape, and the vertical portion 113 of the upper end of the lower can connected to the rolled edge portion 111 can form a complex connection portion having a maze-like shape.

[0060] Therefore, assuming that gas or electrolyte is discharged from the battery, it can only reach the external area after passing through a very complex shape (like a maze) of the connection between the upper can 130 and the lower can. Figure 3 As indicated by the arrow, the leakage path (or leakage route) of gas or electrolyte inside the battery can be quite long and complex, and the friction can also be significant.

[0061] As described above, even if excessive internal pressure is generated by the gas generated inside the battery according to Embodiment 1 of the present invention, the button-type secondary battery 100 can collect gas from inside the battery, thereby preventing the battery from being disassembled or preventing harmful gases from leaking to the outside of the battery due to gas pressure and preventing electrolyte from leaking to the outside of the battery.

[0062] In the button-type secondary battery 100 according to Embodiment 1 of the present invention, a central hole 153 may be formed at the center of the electrode assembly 150, and a central pin 190 may be completely disposed in the central hole 153.

[0063] When the center pin 190 is formed to completely fill the center hole 153, deformation of the electrode assembly 150 can be prevented. The core portion of the electrode assembly 150, which has particularly weak support, may deform due to internal heat and internal gases generated during the battery reaction. When the core deforms as described above, the separator 152 separating the positive and negative electrodes may deform, potentially leading to a short circuit, such as contact between the positive and negative electrodes. However, in this invention, since the center pin 190 is configured to completely fill the center hole 153, such a short circuit can be prevented in advance.

[0064] The button-type secondary battery 100 according to embodiment 1 of the present invention may further include a connector 154 for an electrode 151, which connects the electrode 151 of the electrode assembly 150 to the upper can. The connector 154 for the electrode 151 may have one end connected to the electrode 151 of the electrode assembly 150 and the other end connected in a C-shape to the bottom surface of the electrode terminal portion 133 of the upper can. Figure 2 As shown, when the connector 154 of electrode 151 is connected to the bottom surface of the upper electrode terminal portion 133 in a C-shape, the connector 154 of electrode 151 can have a predetermined elasticity to resist impacts such as falling, so that even if an impact such as falling occurs, the connector 154 of electrode 151 can be effectively prevented from breaking.

[0065] Implementation Method 2

[0066] Figure 4 In the button-type secondary battery according to Embodiment 2 of the present invention Figure 2 A cross-sectional view of region A.

[0067] The difference between Embodiment 2 and Embodiment 1 is that the upper can 230 further includes an upper can protrusion 235, and the lower can further includes a lower can protrusion 215.

[0068] Content that overlaps with Embodiment 1 will be omitted as much as possible, and the focus will be on the differences in describing Embodiment 2. That is, obviously, if necessary, content not described in Embodiment 2 can be considered as content of Embodiment 1.

[0069] Reference Figure 4 In the button-type secondary battery according to Embodiment 2 of the present invention, the upper can 230 further includes an upper can protrusion 235 protruding toward the insulator 270 from at least one of the upper can electrode terminal portion 233, the first bent portion 231 or the second bent portion 232.

[0070] That is, the upper can protrusion 235 can protrude from all of the upper can electrode terminal portion 233, the first bent portion 231 and the second bent portion 232, or can protrude from any one or two of the upper can electrode terminal portion 233, the first bent portion 231 and the second bent portion 232.

[0071] Furthermore, when the upper can protrusion 235 protrudes from the upper can electrode terminal portion 233 toward the insulator 270, particularly when the upper can protrusion 235 protrudes toward the first insulator portion 271, a recess can be formed, allowing the upper can protrusion 235 to also be inserted into the first insulator portion 271. Alternatively, it can be designed so that the recess is not formed in the first insulator portion. This method can be applied to all first insulator portions 271, second insulator portions 272, and third insulator portions 273.

[0072] Furthermore, the lower can may further include a lower can protrusion 215 that protrudes toward the insulator 270 from at least one of the rolled edge portion 211 or the upper vertical portion 213 of the lower can.

[0073] That is, the protrusion 215 of the lower can can protrude from both the rolled edge portion 211 and the vertical portion 213 at the upper end of the lower can, or it can protrude from either the rolled edge portion 211 or the vertical portion 213 at the upper end of the lower can.

[0074] Furthermore, when the lower can protrusion 215 protrudes from the vertical portion 213 at the upper end of the lower can toward the insulator 270, specifically, when the lower can protrusion 215 protrudes toward the first insulator portion 271, a recess can be formed, allowing the lower can protrusion 215 to also insert into the first insulator portion 271. Alternatively, it can be designed so that the recess is not formed in the first insulator portion 271. This method can be applied to all first insulator portions 271, second insulator portions 272, and third insulator portions 273.

[0075] Although the upper can protrusion 235 and the lower can protrusion 215 are formed together, they do not necessarily have to be formed together, and only one of the two protrusions may be formed.

[0076] When the upper can protrusion 235 or the lower can protrusion 215 is formed, the leakage path can be significantly more complex and compounded, so as to more effectively prevent internal gas or electrolyte from leaking out of the battery.

[0077] pH sheets made of methyl orange material can be attached to the outer wall of the lower tank 110.

[0078] Typically, by using alkali metal cations (such as Li) + Na + K + (etc.) and anions (such as PF6) - BF4 - Cl - ,Br - I - ClO4 - AsF6 - CH3CO2 - CF3SO3 - N(CF3SO2)2 - C(CF2SO2)3 -The electrolyte is prepared by dissolving or dissociating salts of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, diethyl ether, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone (γ-butyrolactone), or mixtures thereof in organic solvents, exhibiting a weakly acidic pH of 3.0 to 4.5. Therefore, methyl orange, methyl red, etc., can be used as indicator components to show reactivity relative to the electrolyte within an acidic range. For example, in this invention, when a methyl orange pH plate is attached to the outer wall of the lower tank 110, electrolyte leakage can be clearly detected by color change.

[0079] Although embodiments of the invention have been described with reference to specific implementations, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

[0080] [Explanation of reference numerals in the attached figures]

[0081] 100: Button-type secondary battery

[0082] 110: Lowering the can

[0083] 111, 211: Rolled edge section

[0084] 112, 212: Top surface of the rolled edge portion

[0085] 113, 213: Vertical part at the top of the lower can

[0086] 114: Bottom surface of the lower can

[0087] 120: Collection Space

[0088] 130, 230: Upper tank

[0089] 131, 231: First bending section

[0090] 132, 232: Second bending section

[0091] 133, 233: Upper tank electrode terminal section

[0092] 134: End point of the upper can

[0093] 150, 250: Electrode assemblies

[0094] 151: Electrode

[0095] 152: Diaphragm

[0096] 153: Center Hole

[0097] 154: Electrode connector

[0098] 170, 270: Insulators

[0099] 171, 271: First insulator section

[0100] 172, 272: Second Insulator Section

[0101] 173, 273: Third Insulator Section

[0102] 190: Center Pin

[0103] 215: Lower can protrusion

[0104] 235: Protrusion on the upper can

Claims

1. A button-type secondary battery, the button-type secondary battery comprising: Electrode assembly; The electrode assembly is inserted into the lower tank. as well as An upper can, configured to cover the opening at the upper end of the lower can. The upper part of the lower can has an inwardly recessed rolled edge portion, and The upper can has a curved end, allowing the upper and lower cans to connect to each other, with the end point of the upper can inserted into the rolled edge portion. The upper tank includes: The upper can electrode terminal portion is connected to the electrode of the electrode assembly to form a terminal and is configured to cover the opening at the upper end of the lower can; A first bent portion, the first bent portion being bent to extend vertically from the end of the upper can electrode terminal portion toward the bottom surface of the lower can; and The second curved portion, bent to extend horizontally from the end of the first curved portion toward the central axis of the lower can, and is disposed within the rolled edge portion, and The lower can includes a vertical upper portion, which is bent to extend upward in the vertical direction from the end of the rolled edge portion toward the electrode terminal portion of the upper can.

2. The button-type secondary battery according to claim 1, wherein, A collection space for collecting internal gases is provided between the upper tank and the electrode assembly.

3. The button-type secondary battery according to claim 1, wherein, The vertical portion at the upper end of the lower tank and the first curved portion extend in parallel vertical directions and are positioned to face each other.

4. The button-type secondary battery according to claim 3, wherein, The button-type secondary battery also includes an insulator configured to prevent the upper and lower cans from contacting each other.

5. The button-type secondary battery according to claim 4, wherein, The insulator is made of polybutylene terephthalate (PBT) material.

6. The button-type secondary battery according to claim 4, wherein, The insulator includes: The first insulating portion fills the space surrounded by the top surface of the rolled edge portion, the upper vertical portion of the lower can and the electrode terminal portion of the upper can; A second insulating portion extends from the first insulating portion and fills the space formed between the first curved portion and the upper vertical portion of the lower canister; and A third insulating portion extends from the second insulating portion and fills the space formed between the second curved portion and the rolled edge portion.

7. The button-type secondary battery according to claim 1, wherein, A central hole is formed at the center of the electrode assembly, and A center pin is disposed in the center hole so as to completely fill the center hole.

8. The button-type secondary battery according to claim 1, further comprising an electrode connector configured to connect the electrodes of the electrode assembly to the upper can electrode terminal portion. in, One end of the electrode connector is connected to the electrode of the electrode assembly, and The other end of the electrode connector is connected in a C-shape to the bottom surface of the upper can electrode terminal portion.

9. The button-type secondary battery according to claim 4, wherein, The upper can also include an upper can protrusion that protrudes toward the insulator from at least one of the upper can electrode terminal portion, the first bent portion, or the second bent portion.

10. The button-type secondary battery according to claim 4, wherein, The lower can also include a lower can protrusion, which protrudes toward the insulator from at least one of the rolled edge portion or the upper vertical portion of the lower can.

11. The button-type secondary battery according to claim 1, wherein, The methyl orange pH tablet is attached to the outer wall of the lower tank.

12. The button-type secondary battery according to claim 1, wherein, The diameter of the button-shaped secondary battery is greater than the height of the button-shaped secondary battery.

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