Secondary battery

Abstract

This invention relates to secondary batteries. A secondary battery according to an embodiment of the invention comprises: a cylindrical electrode assembly; a can housing containing the electrode assembly; and a top cap assembly coupled to the can housing to cover the electrode assembly. The top cap assembly may include: a fire extinguishing module comprising fire extinguishing powder sprayed onto the electrode assembly; and a top cap disposed above the fire extinguishing module and electrically connected to the electrode assembly for electrical connection to the outside, and the fire extinguishing module may include: a fire extinguishing capsule having a receiving space for containing fire extinguishing material, and at least a portion of which is formed to be fusible; and a support frame coupled to the fire extinguishing capsule to support the fire extinguishing capsule, and having an opening formed in a portion of the support frame to allow the fire extinguishing material to flow to the electrode assembly.

Description

Technical Field

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0039339, filed in Korea on March 21, 2024, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to secondary batteries, and more specifically, to cylindrical secondary batteries. Background Technology

[0004] Rechargeable secondary batteries can be classified into pouch-type secondary batteries, prismatic secondary batteries, and cylindrical secondary batteries according to their structure and manufacturing method. Among these batteries, cylindrical secondary batteries typically have a structure in which the electrode assembly is housed inside a cylindrical battery can, and a top cap is attached to the top of the battery can.

[0005] Furthermore, in the case of secondary batteries, when a large current flows through them for a short period due to overcharging, external short circuits, puncture, or localized damage, the battery is heated by IR heating, thus posing a risk of explosion. In other words, when the pressure or temperature of a secondary battery rises, decomposition reactions of the active materials and numerous side reactions occur, causing a rapid increase in the battery's temperature. This, in turn, accelerates the reaction between the electrolyte and electrodes. Ultimately, thermal runaway occurs, and when the temperature rises above a certain level, the battery may catch fire, and due to the increased internal pressure, the secondary battery may explode.

[0006] In the case of traditional cylindrical secondary batteries, there is usable internal space such as the hollow section between the top cap and the electrode assembly, but there is a limitation that it cannot fundamentally suppress ignition or flames that may occur under abnormal operating conditions.

[0007] The aforementioned background technology was learned or obtained by the inventor in the process of deriving the disclosure of this application, and may not necessarily be considered as known technology disclosed to the public before the filing of this application. Summary of the Invention

[0008] Technical issues

[0009] This disclosure aims to solve the above-mentioned problems, and therefore aims to provide a secondary battery that improves thermal stability by including a top cap assembly with a fire extinguishing module.

[0010] Technical solution

[0011] A secondary battery according to embodiments of the present disclosure may include: a cylindrical electrode assembly; a can housing that accommodates the electrode assembly; and a top cap assembly coupled to the can housing to cover the electrode assembly, wherein the top cap assembly may include: a fire extinguishing module having fire extinguishing powder that is sprayed onto the electrode assembly; and a top cap disposed above the fire extinguishing module and electrically connected to the electrode assembly to enable electrical connection to the outside, wherein the fire extinguishing module may include: a fire extinguishing capsule having a receiving space formed therein for accommodating fire extinguishing material, and at least a portion of the fire extinguishing capsule being formed to be fusible; and a support frame coupled to the fire extinguishing capsule to support the fire extinguishing capsule, and the support frame having an opening formed in a portion of the support frame to allow the fire extinguishing material to flow to the electrode assembly.

[0012] The support frame may include: a base that supports the fire extinguishing capsule; and a protrusion that extends upward from the central portion of the base to a predetermined height.

[0013] A through hole can be formed in the central part of the fire extinguishing capsule for the protrusion to pass through.

[0014] The protrusion may include: a baffle plate electrically connected to the electrode assembly and configured to block overcurrent; and a connecting frame extending vertically between the baffle plate and the base.

[0015] Multiple openings can be formed in the base.

[0016] Multiple openings can be spaced apart from each other in the circumferential direction on the base.

[0017] The fire extinguishing capsule may include: a shell portion forming a receiving space; and a molten portion formed on the bottom surface of the shell portion and configured to melt and eject fire extinguishing material above a preset temperature.

[0018] The molten section can be configured to protrude downward from the bottom surface of the shell section.

[0019] The bottom surface of the shell part can be formed to slope towards the molten part in the direction of decreasing height.

[0020] The molten part can be inserted into the opening.

[0021] Multiple openings can be formed to be spaced apart from each other in the circumferential direction on the base.

[0022] Multiple molten sections can be spaced apart from each other circumferentially on the bottom surface of the shell section, corresponding to the location of the opening.

[0023] According to embodiments of the present disclosure, a top cap assembly is configured to be coupled to a cylindrical electrode assembly, and the top cap assembly may include: an extinguishing capsule having a receiving space for extinguishing material formed therein, and at least a portion of the extinguishing capsule being fusible; a support frame coupled to the extinguishing capsule to support the extinguishing capsule, and having an opening formed in a portion of the support frame to allow the extinguishing material to flow to the electrode assembly; and a top cap disposed above the coupled support frame and the extinguishing capsule, and configured to be electrically connected to the electrode assembly to enable electrical connection to the outside.

[0024] The top cap assembly may also include a vent cap disposed between the top cap and the fire extinguishing capsule, the vent cap being configured to rupture above a preset pressure to release gas, and the vent cap having an edge formed to curve around the fire extinguishing capsule.

[0025] According to embodiments of the present disclosure, a fire extinguishing module is disposed above a cylindrical electrode assembly to spray fire extinguishing material. The fire extinguishing module may include: a fire extinguishing capsule having a receiving space for containing fire extinguishing material, and at least a portion of the fire extinguishing capsule being fusible; and a support frame connected to the fire extinguishing capsule to support the fire extinguishing capsule, and an opening being formed in a portion of the support frame to allow the fire extinguishing material to flow to the electrode assembly.

[0026] Beneficial effects

[0027] According to one embodiment of the present disclosure, the thermal stability of a secondary battery can be improved by including a top cap assembly with a fire extinguishing module.

[0028] Additionally, it may include effects that are readily predictable by those skilled in the art from configurations based on embodiments of this disclosure. Attached Figure Description

[0029] Figure 1 This is a cross-sectional view of the secondary battery according to Embodiment 1 of this disclosure.

[0030] Figure 2 It is shown Figure 1 A cross-sectional view of the top cap assembly of the secondary battery shown.

[0031] Figure 3 It is shown Figure 2 A cross-sectional view of the connection structure of the fire extinguishing module of the top cap assembly shown.

[0032] Figure 4 This is a plan view of the support frame of the fire extinguishing module according to Embodiment 1 of this disclosure.

[0033] Figure 5 It is along Figure 4The sectional view taken by line aa in the diagram.

[0034] Figure 6 This is a bottom view of the fire extinguishing capsule of the fire extinguishing module according to Embodiment 1 of this disclosure.

[0035] Figure 7 It is along Figure 6 The sectional view is taken from line bb in the middle.

[0036] Figure 8 This is a plan view of the vent cover of the secondary battery according to Embodiment 1 of this disclosure.

[0037] Figure 9 It is along Figure 8 The sectional view is taken by the line cc in the middle.

[0038] Figure 10 This is a plan view of the support frame of the fire extinguishing module according to Embodiment 2 of this disclosure.

[0039] Figure 11 It is along Figure 10 The sectional view is taken from the line dd in the middle. Detailed Implementation

[0040] In the following, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings to enable those skilled in the art to readily implement the present disclosure. The following description is one of several aspects of the embodiments, and in describing one embodiment, specific descriptions of well-known functions or configurations will be omitted to clarify the main points of the disclosure.

[0041] In this specification, when reference numerals are attached to elements in each figure, the same or similar reference numerals are attached to the same or similar elements throughout the specification. In other embodiments, the same names will be used to describe components included in any embodiment and components that include common functions. It should be understood that the terms or words used in this specification and the appended claims should not be construed as limited to their general and dictionary meanings, but rather are interpreted according to their meanings and concepts corresponding to the technical aspects of this disclosure, based on the principle of allowing the inventors to appropriately define terms to obtain the best interpretation.

[0042] Furthermore, this disclosure is not limited to the embodiments described above, and those skilled in the art to which this disclosure pertains can make various modifications and variations based on these descriptions. Therefore, the concept of this disclosure should not be limited to the embodiments described above, and the appended claims and all their equivalents or variations are considered to fall within the scope of this disclosure.

[0043] Implementation Method 1

[0044] Figure 1This is a cross-sectional view of the secondary battery according to Embodiment 1 of this disclosure.

[0045] Reference Figure 1 According to Embodiment 1 of this disclosure, the secondary battery may include an electrode assembly 1, a can housing 3, and a top cap assembly 2.

[0046] Electrode assembly 1 may include a positive electrode, a negative electrode, and a diaphragm inserted between the positive and negative electrodes. Electrode assembly 1 may be a wound-core type electrode assembly with a cylindrical shape. In this case, electrode assembly 1 may have a structure in which the elongated positive and negative electrodes are wound together with the diaphragm inserted between them. Electrode assembly 1 may be formed into a cylindrical shape that extends in a direction perpendicular to the length direction and has a circular cross-section perpendicular to the length direction.

[0047] The can housing 3 can be configured to house the electrode assembly 1. The can housing 3 can be made of a metallic material and can have an electrode assembly space for housing the electrode assembly 1. The can housing 3 can have a shape that surrounds the electrode assembly 1 and opens upwards. The can housing 3 can be electrically connected to the electrode assembly 1. The can housing 3 can be electrically connected, for example, to the negative electrode of the electrode assembly 1.

[0048] The top cap assembly 2 can be connected to the can housing 3 to cover the electrode assembly 1. The top cap assembly 2 can be connected to the upper opening of the can housing 3. The top cap assembly 2 can be electrically connected to the electrode assembly 1 while connected to the can housing 3. The top cap assembly 2 can be electrically connected to, for example, the positive terminal of the electrode assembly 1.

[0049] The secondary battery according to Embodiment 1 of this disclosure may further include a gasket 4. The gasket 4 may be configured to ensure the airtightness of the electrode assembly 1 housed within the can housing 3. The gasket 4 may be disposed between the top cap assembly 2 and the can housing 3, and may be made of a material having a predetermined elasticity. The gasket 4 may be provided, for example, in the form of a circular O-ring having a circular cross-section perpendicular to its length direction, and the gasket 4 may be folded at its top and bottom ends to support the top cap assembly 2 without deviation.

[0050] Figure 2 It is shown Figure 1 A cross-sectional view of the top cap assembly of the secondary battery shown.

[0051] Reference Figure 2 The top cap assembly 2 may include a top cap 10, an exhaust cover 20, and a fire extinguishing module 30.

[0052] The top cap 10 can be made of a conductive material. For example, the top cap 10 can be made of a metal material such as nickel-plated iron. The top cap 10 can be electrically connected to the electrode assembly 1 via the vent cap 20. The top cap 10 can be configured as an integral shape having a circular plate corresponding to the shape of the can housing 3, but is not limited thereto. The top cap 10 is located at the uppermost end of the can housing 3 and can be exposed to the outside to enable electrical connection to the outside.

[0053] The vent cap 20 can be attached to the underside of the top cap 10. The vent cap 20 can be positioned between the top cap 10 and the fire extinguishing module 30. The vent cap 20 can be configured to rupture above a preset pressure to expel gas from inside the canister housing 3. The vent cap 20 can be made of a conductive material, such as a metallic material, for electrical connection to the top cap 10. Multiple notches for rupture can be formed in the vent cap 20. The vent cap 20 can have the shape of a fire extinguishing capsule 31 surrounding the fire extinguishing module 30. (See below for reference.) Figure 8 and Figure 9 A more detailed description of the shape of the exhaust cover 20 is provided.

[0054] The fire extinguishing module 30 can be configured to spray fire extinguishing material onto the electrode assembly 1. The fire extinguishing module 30 can spray fire extinguishing material onto the electrode assembly 1 to prevent fire in the event of abnormal behavior within the electrode assembly 1, such as fire caused by a short circuit or a sudden temperature change due to the external environment. The fire extinguishing module 30 can be connected to the lower side of the exhaust cover 20. Therefore, the fire extinguishing module 30, the exhaust cover 20, and the top cap 10 can be stacked and connected sequentially in the direction facing upwards towards the electrode assembly 1. (Refer to the following...) Figures 3 to 7 A more detailed description of the shape and function of the fire extinguishing module 30 is provided.

[0055] Figures 3 to 7 The structure of the fire extinguishing module 30 according to Embodiment 1 of this disclosure is shown. Specifically, Figure 3 This is a cross-sectional view showing the connection structure of the fire extinguishing module 30 according to Embodiment 1 of this disclosure. Figure 4 This is a plan view of the support frame 32 of the fire extinguishing module 30 according to Embodiment 1 of this disclosure. Figure 5 It is along Figure 4 The cross-sectional view of the support frame 32 is taken from line aa. Figure 6 This is a bottom view of the fire extinguishing capsule 31 of the fire extinguishing module 30 according to Embodiment 1 of this disclosure. Figure 7 It is along Figure 6 The sectional view is taken from line bb in the middle.

[0056] Reference Figures 3 to 7 According to Embodiment 1 of this disclosure, the fire extinguishing module 30 may include a support frame 32 and a fire extinguishing capsule 31. The support frame 32 and the fire extinguishing capsule 31 may be connected.

[0057] The support frame 32 can be connected to the fire extinguishing capsule 31 and can be configured to support the fire extinguishing capsule 31. The support frame 32 can have an overall shape of a circular frame corresponding to the shape of the cylindrical electrode assembly 1 and the canister shell 3. The support frame 32 can have multiple openings 323, which are configured to allow the extinguishing material of the fire extinguishing capsule 31 to flow toward the electrode assembly 1. The fire extinguishing capsule 31 is connected to the upper side of the support frame 32, and the extinguishing material of the fire extinguishing capsule 31 can flow directly toward the electrode assembly 1 through the openings 323 of the support frame 32.

[0058] The support frame 32 may include a base 321 and a protrusion 322.

[0059] The base 321 can be configured to support the fire extinguishing capsule 31. The base 321 can support the fire extinguishing capsule 31 so that the fire extinguishing capsule 31 does not shift downward. The base 321 is formed in the shape of a circular plate, and a protrusion 322 can be formed in the central region of the base 321.

[0060] An opening 323 may be formed in the base 321. As described above, multiple openings 323 may be formed in the base 321 and may be configured to allow the extinguishing material inside the extinguishing capsule 31 to flow to the electrode assembly 1. The opening 323 may be an arc shape with a predetermined width. Multiple openings 323 may be spaced apart from each other in the circumferential direction. For example, four arc-shaped openings 323 may be spaced apart from each other at equal intervals in the circumferential direction. In this case, the multiple spaced openings 323 may have a protrusion 322 around the center of the base 321. A bridging portion 324 connecting the edge portion and the central portion of the base 321 may be formed between adjacent openings 323. When four openings 323 are spaced apart from each other, four bridging portions 324 may be provided accordingly. The bridging portions 324 may be located between the spaced-apart molten portions 313 described later.

[0061] The protrusion 322 may be formed to protrude upward from the central portion of the base 321 to a predetermined height. The protrusion 322 may be electrically connected to the electrode assembly 1. The protrusion 322 may penetrate through the through hole 311 of the fire extinguishing capsule 31 (described later) to engage with the through hole 311. The protrusion may contact the vent cap 20.

[0062] The fire extinguishing capsule 31 can be configured to contain fire extinguishing material to be sprayed onto the electrode assembly 1. The fire extinguishing capsule 31 can be provided with a containing space 314 for containing fire extinguishing material, and the fire extinguishing material contained in the containing space 314 can be configured to be sprayed onto the electrode assembly 1 when an environment with a preset temperature or higher temperature occurs.

[0063] The fire extinguishing capsule 31 can be connected to and supported by the support frame 32. The fire extinguishing capsule 31 can also be formed into an integral circular shape corresponding to the shape of the cylindrical canister shell 3. As described above, a through hole 311 is formed in the central part of the fire extinguishing capsule 31 for the protrusion 322 of the support frame 32 to pass through, so that the fire extinguishing capsule 31 can have an annular or ring-shaped shape.

[0064] The fire extinguishing capsule may include a shell portion 312 and a molten portion 313.

[0065] The housing portion 312 can be configured to form a receiving space 314 for accommodating fire extinguishing material. The housing portion 312 forms the overall appearance of the fire extinguishing capsule 31 and can have a circular ring shape in which the receiving space 314 is formed. The top surface of the housing portion 312 can face the exhaust cover 20. A portion of the bottom surface of the housing portion 312 can be configured to be received in and supported by the support frame 32, and the remaining portion can be configured to be exposed through the opening 323 of the support frame 32 to face the molten portion 313 of the electrode assembly 1.

[0066] At least a portion of the housing portion 312 may be formed as inclined. Specifically, the bottom surface 3121 of the housing portion 312 surrounding the molten portion 313 may be configured as inclined such that its height gradually decreases in the direction toward the molten portion 313. By adopting this configuration, when the molten portion 313 melts, the extinguishing material can flow more easily in the downward direction toward the electrode assembly 1.

[0067] The molten portion 313 can be configured to melt above a preset temperature and spray extinguishing material into the electrode assembly 1. The molten portion 313 can be formed on the bottom surface of the housing portion 312. The molten portion 313 can have a shape that protrudes downward from the bottom surface of the housing portion 312. The molten portion 313 can extend from the housing portion 312, and the molten portion 313 and the housing portion 312 can be integrally formed, for example. The molten portion 313 can be made of a material that melts at a preset reference temperature, such that it can melt above the preset temperature to spray extinguishing material into the receiving space 314 inside the housing portion 312.

[0068] The molten portion 313 can be inserted into the opening 323 of the support frame 32, protruding from the bottom surface of the shell portion 312. In this case, multiple molten portions 313 can be formed corresponding to the openings 323 of the support frame 32, and similarly, multiple molten portions 313 can be positioned spaced apart from each other in the circumferential direction. The molten portions 313 can be formed into an arc shape with a predetermined width. For example, four molten portions 313 with an arc shape can be connected in a manner that is equally spaced in the circumferential direction and inserted into the openings 323 of the support frame 32. The positions of the openings 323 of the support frame 32 and the positions of the molten portions 313 of the fire extinguishing capsule 31 can correspond to each other. The aforementioned bridging portion 324 of the support frame 32 can be connected in the space between adjacent molten portions 313.

[0069] Figure 8 and Figure 9 The vent cover 20 of the top cap assembly according to Embodiment 1 of this disclosure is shown. Figure 8 This is a plan view of the vent cover 20 of the top cap assembly according to Embodiment 1 of this disclosure. Figure 9 It is along Figure 8 The sectional view is taken by the line cc in the middle.

[0070] As described above, when gas is generated in the electrode assembly 1 due to overheating or other issues, the vent cap 20 can be configured to rupture above a preset pressure to release the internal gas to the outside. The vent cap 20 is disposed between the top cap 10 and the fire extinguishing module 30, and can have multiple notches to facilitate rupture.

[0071] Reference Figure 8 and Figure 9 The exhaust cap 20 can be formed in the shape of a circular plate to cover the fire extinguishing module 30, and a curved portion 21 can be formed at its edge. In this case, the exhaust cap 20 can have the shape of a fire extinguishing capsule 31 that surrounds the fire extinguishing module 30.

[0072] The curved portion 21 of the vent cap 20 can surround the fire extinguishing capsule 31 of the fire extinguishing module 30. This configuration improves the structural stability of the fire extinguishing capsule 31 and, additionally, enhances the stability of the electrical connection between the support frame 32 and the vent cap 20, which are connected to the fire extinguishing capsule 31. The end of the curved portion 21 of the vent cap 20 can have a curved shape in the direction of insertion into the space between the fire extinguishing capsule 31 and the support frame 32.

[0073] Implementation Method 2

[0074] Figure 10 and Figure 11 The support frame 32 of the fire extinguishing module according to Embodiment 2 of this disclosure is shown. Figure 10This is a plan view of the support frame 32 of the fire extinguishing module according to Embodiment 2 of this disclosure. Figure 11 It is along Figure 10 The sectional view of the support frame 32 is taken by line dd.

[0075] The difference between Embodiment 2 and Embodiment 1 is that a baffle plate 3221 is provided in the support frame. It should be noted that, apart from the differences, the content of the secondary battery according to Embodiment 1 of this disclosure can also be applied to Embodiment 2. Therefore, the commonalities with Embodiment 1 will be omitted as much as possible, and the focus will be on describing the differences in Embodiment 2.

[0076] Reference Figure 10 and Figure 11 The protrusion 322 of the support frame 32 may include a baffle plate 3221 and a connecting frame 3222.

[0077] The baffle plate 3221 can be electrically connected to the electrode assembly 1. The baffle plate 3221 can be made of a conductive material. The baffle plate 3221 can be electrically connected to the electrode assembly 1 and can be configured to block overcurrent. The baffle plate 3221 can be a current interruption device (CID) filter, which is configured to block current when a preset allowable current or greater is generated. The baffle plate 3221 can be electrically connected to the exhaust cap 20 in contact with it.

[0078] A connecting frame 3222 can extend vertically between the baffle plate 3221 and the base 321. The connecting frame 3222 can support the baffle plate 3221. The connecting frame 3222 can extend upward from the inner end of the base 321. The connecting frame 3222 can be made of the same material as the base 321. The connecting frame 3222 can be integrally formed with the base 321. By adopting this configuration, the thermal and electrical stability of the secondary battery can be further improved by spraying extinguishing powder and preventing the generation of overcurrent.

[0079] The present disclosure has been described above with respect to a limited number of embodiments and accompanying drawings. However, the above description is merely an exemplary description of the technical concept of the present disclosure, and various modifications and changes can be made by those skilled in the art to which the present disclosure pertains without departing from the basic characteristics of the present disclosure.

[0080] Therefore, the embodiments disclosed herein are not intended to limit the technical concept of this disclosure, but are for illustrative purposes, and the scope of the technical concept of this disclosure is not limited by these embodiments. The scope of protection of this disclosure should be interpreted in accordance with the appended claims, and all technical concepts within the equivalent scope thereof should be interpreted as being included within the scope of this disclosure.

[0081] [List of reference numerals]

[0082] 1: Electrode assembly

[0083] 2: Top cap assembly

[0084] 3: Tank shell

[0085] 4: Washers

[0086] 10: Top hat

[0087] 20: Exhaust cover

[0088] 30: Fire Extinguishing Module

[0089] 31: Fire Extinguishing Capsule

[0090] 311: Through hole

[0091] 312: Shell section

[0092] 3121: Bottom surface

[0093] 313: Melting section

[0094] 314: Capacity

[0095] 32: Supporting Frame

[0096] 321: Base

[0097] 322: Protrusion

[0098] 3221: Baffle

[0099] 3222: Connection Frame

[0100] 323: Opening

[0101] 324: Bridging section

Claims

1. A secondary battery, the secondary battery comprising: Cylindrical electrode assembly; A tank housing that accommodates the electrode assembly; as well as A top cap assembly, which is attached to the can housing to cover the electrode assembly. The top cap assembly includes: a fire extinguishing module having fire extinguishing powder that can be sprayed onto the electrode assembly; and a top cap disposed above the fire extinguishing module and electrically connected to the electrode assembly to enable electrical connection to the outside. The fire extinguishing module includes: A fire extinguishing capsule, wherein a containment space for fire extinguishing material is formed within the fire extinguishing capsule, and at least a portion of the fire extinguishing capsule is formed to be fusible; and A support frame is connected to the fire extinguishing capsule to support the fire extinguishing capsule, and the support frame has an opening formed in a portion of the support frame to allow the fire extinguishing material to flow to the electrode assembly.

2. The secondary battery according to claim 1, in, The supporting framework includes: Base, the base supporting the fire extinguishing capsule; and A protrusion that extends upward from the central portion of the base to a predetermined height.

3. The secondary battery according to claim 2, in, A through hole is formed in the central part of the fire extinguishing capsule for the protrusion to pass through.

4. The secondary battery according to claim 2, in, The protrusion includes: A baffle plate, electrically connected to the electrode assembly and configured to block overcurrent; and A connecting frame that extends vertically between the barrier plate and the base.

5. The secondary battery according to claim 2, in, The openings are formed in multiple ways in the base.

6. The secondary battery according to claim 5, in, The plurality of openings are spaced apart from each other in the circumferential direction on the base.

7. The secondary battery according to claim 2, in, The fire extinguishing capsule includes: The housing portion forms the receiving space; and A molten section is formed on the bottom surface of the housing portion and is configured to melt and spray the fire extinguishing material at a preset temperature.

8. The secondary battery according to claim 7, in, The molten portion is configured to protrude downward from the bottom surface of the housing portion.

9. The secondary battery according to claim 7, in, The bottom surface of the shell portion is formed to slope toward the molten portion in a direction of decreasing height.

10. The secondary battery according to claim 7, in, The molten portion is inserted into the opening.

11. The secondary battery according to claim 7, in, The plurality of openings are formed to be spaced apart from each other in the circumferential direction on the base, and The plurality of molten portions and the openings are spaced apart from each other along the circumferential direction on the bottom surface of the housing portion.

12. A cap assembly configured to be coupled to a cylindrical electrode assembly, the cap assembly comprising: A fire extinguishing capsule having a containment space for fire extinguishing material, and at least a portion of the fire extinguishing capsule being fusible; A support frame is connected to the fire extinguishing capsule to support the fire extinguishing capsule, and an opening is formed in a portion of the support frame to allow the fire extinguishing material to flow to the electrode assembly; as well as A top cap is disposed above the connected support frame and the fire extinguishing capsule, and is configured to be electrically connected to the electrode assembly to enable electrical connection to the outside.

13. The cap assembly of claim 12, further comprising: An exhaust cap is disposed between the top cap and the fire extinguishing capsule, the exhaust cap being configured to rupture above a preset pressure to release gas, and the exhaust cap having an edge formed to curve around the fire extinguishing capsule.

14. A fire extinguishing module, the fire extinguishing module being disposed above a cylindrical electrode assembly to spray fire extinguishing material, the fire extinguishing module comprising: A fire extinguishing capsule having a containment space for accommodating the fire extinguishing material, and at least a portion of the fire extinguishing capsule being fusible; as well as A support frame is connected to the fire extinguishing capsule to support the fire extinguishing capsule, and an opening is formed in a portion of the support frame to allow the fire extinguishing material to flow to the electrode assembly.

Images