Secondary battery

Abstract

The present invention relates to a secondary battery. A secondary battery according to an embodiment of the present invention comprises: 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. The top cap assembly may comprise: a fire-extinguishing module including 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 be electrically connected to the outside, and the fire-extinguishing module may comprise: a fire-extinguishing capsule having an accommodation space for accommodating fire-extinguishing material, and having at least a portion formed to be meltable; and a support frame coupled to the fire-extinguishing capsule to support the fire-extinguishing capsule and having an opening formed in a portion thereof so that the fire-extinguishing material flows to the electrode assembly.

Description

secondary battery

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2024-0039339, filed March 21, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a secondary battery, and more particularly to a cylindrical secondary battery.

[0005] Secondary batteries capable of repeated charging and discharging can be divided into pouch-type secondary batteries, square secondary batteries, and cylindrical secondary batteries, depending on their structure and manufacturing method. Among these, cylindrical secondary batteries typically have a structure in which an electrode assembly is housed inside a cylindrical battery can and a top cap is attached to the top of the battery can.

[0006] Meanwhile, in the case of secondary batteries, if a large current flows in a short period of time due to overcharging, external short circuit, needle penetration, or local damage, there is a risk of explosion due to the IR heat heating the battery. In other words, when the pressure or temperature of the secondary battery increases, the decomposition reaction of the active material and numerous side reactions occur, which rapidly increases the temperature of the secondary battery, and this in turn accelerates the reaction between the electrolyte and the electrode. Ultimately, a thermal runaway phenomenon occurs in which the temperature of the battery rapidly increases, and if the temperature rises above a certain level, the battery may ignite, and the secondary battery may explode due to the increased internal pressure.

[0007] In the case of conventional cylindrical secondary batteries, there is an internal space that can be utilized, such as a hollow space between the top cap and the electrode assembly, but there was a limitation in that there was no way to fundamentally suppress ignition or flames that occurred under abnormal operating conditions.

[0008] The background technology described above is something that the inventor possessed or acquired in the process of deriving the disclosure of the present application, and cannot necessarily be said to be a publicly known technology disclosed to the general public prior to the present application.

[0009] The present invention has been devised to solve the above problems, and an object of one embodiment of the present invention is to provide a secondary battery having improved thermal stability, including a top cap assembly having a digestion module.

[0010] According to an embodiment of the present invention, a secondary battery includes: a cylindrical electrode assembly; a can housing that accommodates the electrode assembly; and a top cap assembly coupled to the can housing so as to cover the electrode assembly, wherein the top cap assembly includes a fire extinguishing module that has fire extinguishing powder sprayed onto the electrode assembly, and a top cap that is arranged on an upper side of the fire extinguishing module and electrically connected to the electrode assembly so as to enable electrical connection with the outside, wherein the fire extinguishing module may include: a fire extinguishing capsule having a receiving space that accommodates a fire extinguishing substance, at least one portion of which is formed to be meltable; and a support frame coupled to the fire extinguishing capsule so as to support the fire extinguishing substance, and having an opening formed in one portion so that the fire extinguishing substance flows into the electrode assembly.

[0011] The above support frame may include a base portion that supports the digestive capsule; and a protrusion portion that protrudes upward at a predetermined height from the central portion of the base portion.

[0012] A through hole through which the protrusion penetrates may be formed in the central portion of the above digestive capsule.

[0013] The protrusion may include a blocking plate electrically connected to the electrode assembly to block overcurrent; and a connecting frame extending vertically between the blocking plate and the base portion.

[0014] The above openings may be formed in multiple numbers in the base portion.

[0015] A plurality of said openings may be spaced apart from each other along the circumferential direction on said base portion.

[0016] The above digestive capsule may include a housing portion forming the receiving space; and a melting portion formed on the lower surface of the housing portion and configured to melt at a preset temperature or higher and eject the digestive substance.

[0017] The above melting portion may be provided to protrude downward from the bottom surface of the housing portion.

[0018] The bottom surface of the above housing portion may be formed to be inclined in a direction in which the height decreases toward the above melting portion.

[0019] The above melting part can be inserted into the above opening.

[0020] A plurality of the above openings are formed spaced apart from each other along the circumferential direction on the base portion,

[0021] The above melting portions may be spaced apart from each other in the circumferential direction on the bottom surface of the housing portion in a plurality corresponding to the position of the opening.

[0022] A top cap assembly according to an embodiment of the present invention may include a digestive capsule which is provided to be coupled with a cylindrical electrode assembly, has a receiving space formed to receive a digestive substance, and at least one portion thereof is formed to be meltable; a support frame which is coupled to the digestive capsule to support the digestive capsule, and has an opening formed in one portion thereof to allow the digestive substance to flow to the electrode assembly; and a top cap which is arranged on an upper side of the combined upper limb support frame and the digestive capsule, and is provided to be electrically connected to the electrode assembly to enable electrical connection with the outside.

[0023] The top cap assembly may further include a vent cover disposed between the top cap and the digestive capsule, configured to burst when a pressure exceeds a preset pressure to release gas, and having a curved edge formed to surround the digestive capsule.

[0024] A fire extinguishing module according to an embodiment of the present invention may include a fire extinguishing capsule provided on an upper side of a cylindrical electrode assembly to eject a fire extinguishing substance, a receiving space for receiving the fire extinguishing substance is formed, and at least one portion thereof is formed to be meltable; and a support frame coupled to the fire extinguishing capsule to support the fire extinguishing capsule, and an opening formed in one portion thereof to allow the fire extinguishing substance to flow into the electrode assembly.

[0025] A secondary battery according to one embodiment of the present invention can have improved thermal stability by including a top cap assembly having a digestion module.

[0026] In addition, the configurations according to the embodiments of the present invention may include effects that can be easily predicted by those skilled in the art.

[0027] Figure 1 shows a cross-sectional view of a secondary battery according to Example 1 of the present invention.

[0028] Fig. 2 is a cross-sectional view showing the top cap assembly of the secondary battery illustrated in Fig. 1.

[0029] Fig. 3 is a cross-sectional view showing the joint structure of the digestion module of the top cap assembly illustrated in Fig. 2.

[0030] Figure 4 shows a plan view of a support frame of a digestion module according to Example 1 of the present invention.

[0031] Figure 5 is a cross-sectional view taken along line aa shown in Figure 4.

[0032] Figure 6 shows a bottom view of a digestive capsule of a digestive module according to Example 1 of the present invention.

[0033] Figure 7 is a cross-sectional view taken along line bb shown in Figure 6.

[0034] Figure 8 shows a plan view of a vent cover of a secondary battery according to Example 1 of the present invention.

[0035] Fig. 9 is a cross-sectional view taken along line cc shown in Fig. 8.

[0036] Figure 10 shows a plan view of a support frame of a digestion module according to Example 2 of the present invention.

[0037] Fig. 11 is a cross-sectional view taken along line dd shown in Fig. 10.

[0038] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. The following description is one of several aspects of the embodiments, and in describing one embodiment, detailed descriptions of well-known functions or configurations will be omitted to clarify the gist of the present invention.

[0039] In this specification, when adding reference signs to components in each drawing, the same or similar reference signs are attached to identical or similar components throughout the specification. Components included in one embodiment and components that have common functions will be described using the same names in other embodiments. Terms or words used in this specification and the claims should not be interpreted as limited to their usual or dictionary meanings, and should be interpreted as meanings and concepts that are consistent with the technical spirit of the present invention based on the principle that the inventor can appropriately define the concept of the term to best explain his or her invention.

[0040] Furthermore, the present invention is not limited to the embodiments described above, and those skilled in the art will readily appreciate that various modifications and variations can be made based on this disclosure. Therefore, the spirit of the present invention should not be construed as limited to the embodiments described above, and all variations equivalent to or equivalent to the claims, as well as the scope of the claims, are deemed to fall within the scope of the present invention.

[0041] Example 1

[0042] Figure 1 shows a cross-sectional view of a secondary battery according to Example 1 of the present invention.

[0043] Referring to FIG. 1, a secondary battery according to Example 1 of the present invention may include an electrode assembly (1), a can housing (3), and a top cap assembly (2).

[0044] An electrode assembly (1) may include a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The electrode assembly (1) may be a jelly roll-type electrode assembly having a cylindrical shape. In this case, the electrode assembly (1) may have a structure in which long sheet-shaped positive electrodes and negative electrodes are rolled up with a separator interposed therebetween. The electrode assembly (1) may be formed in a cylindrical shape that extends in a vertical direction in a longitudinal direction and has a circular cross-section perpendicular to the longitudinal direction.

[0045] The can housing (3) may be provided to accommodate the electrode assembly (1). The can housing (3) may be formed of a metal material and may have an electrode assembly space for accommodating the electrode assembly (1). The can housing (3) may surround the electrode assembly (1) and may have an upwardly open shape. The can housing (3) may be electrically connected to the electrode assembly (1). For example, the can housing (3) may be electrically connected to a negative electrode of the electrode assembly (1).

[0046] The top cap assembly (2) can be coupled to the can housing (3) to cover the electrode assembly (1). The top cap assembly (2) can be coupled to the upper opening of the can housing (3). The top cap assembly (2) can be electrically connected to the electrode assembly (1) while coupled to the can housing (3). The top cap assembly (2) can be electrically connected to, for example, the positive electrode of the electrode assembly (1).

[0047] The secondary battery according to Embodiment 1 of the present invention may further include a gasket (4). The gasket (4) may be provided to ensure airtightness of the electrode assembly (1) accommodated in the can housing (3). The gasket (4) may be disposed between the top cap assembly (2) and the can housing (3), and may be formed of a material having a predetermined elasticity. The gasket (4) may be provided, for example, in the shape of a circular O-ring having a cross-section perpendicular to the longitudinal direction and having a circular shape, and may be folded at the top and bottom to support the top cap assembly (2) so that it does not come off.

[0048] Fig. 2 is a cross-sectional view showing the top cap assembly of the secondary battery illustrated in Fig. 1.

[0049] Referring to FIG. 2, the top cap assembly (2) may include a top cap (10), a vent cover (20), and a fire extinguishing module (30).

[0050] The top cap (10) may be formed of a conductive material. The top cap (10) may be formed of a metal material, such as nickel-plated iron, for example. The top cap (10) may be electrically connected to the electrode assembly (1) via the vent cover (20). The top cap (10) may be provided to have an overall circular plate shape corresponding to the shape of the can housing (3), but is not limited thereto. The top cap (10) may be positioned at the top of the can housing (3) and may be exposed to the outside to enable electrical connection with the outside.

[0051] The vent cover (20) may be coupled to the lower side of the top cap (10). The vent cover (20) may be positioned between the top cap (10) and the extinguishing module (30). The vent cover (20) may be provided to burst when a preset pressure is exceeded, thereby releasing gas inside the can housing (3). The vent cover (20) may be formed of a conductive material, for example, a metal material, so as to be electrically connected to the top cap (10). A plurality of notches for bursting may be formed in the vent cover (20). The vent cover (20) may have a shape that surrounds the extinguishing capsule (31) of the extinguishing module (30). A more detailed shape of the vent cover (20) will be described in detail with reference to FIGS. 8 and 9 to be described later.

[0052] The fire extinguishing module (30) may be provided to spray a fire extinguishing agent onto the electrode assembly (1). The fire extinguishing module (30) may prevent a fire by spraying the fire extinguishing agent onto the electrode assembly (1) when an abnormal behavior occurs in the electrode assembly (1), such as a short circuit or ignition due to a rapid temperature change caused by the external environment. The fire extinguishing module (30) may be coupled to the lower side of the vent cover (20). Accordingly, the fire extinguishing module (30), the vent cover (20), and the top cap (10) may be sequentially stacked and coupled in a direction toward the upper side of the electrode assembly (1). A more detailed shape and function of the fire extinguishing module (30) will be described in detail below with reference to FIGS. 3 to 7.

[0053] Figures 3 to 7 illustrate the structure of a fire extinguishing module (30) according to Embodiment 1 of the present invention. Specifically, Figure 3 is a cross-sectional view illustrating a coupling structure of a fire extinguishing module (30) according to Embodiment 1 of the present invention. Figure 4 is a plan view of a support frame (32) of a fire extinguishing module (30) according to Embodiment 1 of the present invention, and Figure 5 is a cross-sectional view of the support frame (32) taken along line aa illustrated in Figure 4. Figure 6 is a bottom view of a fire extinguishing capsule (31) of a fire extinguishing module (30) according to Embodiment 1 of the present invention, and Figure 7 is a cross-sectional view taken along line bb illustrated in Figure 6.

[0054] Referring to FIGS. 3 to 7, the digestion module (30) according to Embodiment 1 of the present invention may include a support frame (32) and a digestion capsule (31). The support frame (32) and the digestion capsule (31) may be combined.

[0055] A support frame (32) may be provided to be coupled to the digestion capsule (31) and support the digestion capsule (31). The support frame (32) may have an overall circular frame shape corresponding to the shape of the cylindrical electrode assembly (1) and the can housing (3). A plurality of openings (323) may be formed in the support frame (32) so that the digestion material of the digestion capsule (31) may flow toward the electrode assembly (1). The digestion capsule (31) is coupled to the upper side of the support frame (32), and the digestion material of the digestion capsule (31) may flow directly to the electrode assembly (1) through the openings (323) of the support frame (32).

[0056] The support frame (32) may include a base portion (321) and a protrusion portion (322).

[0057] The base portion (321) may be provided to support the digestive capsule (31). The base portion (321) may support the digestive capsule (31) so that the digestive capsule (31) does not fall downward. The base portion (321) is formed in the shape of a circular plate, and a protrusion (322) may be formed in the central region of the base portion (321).

[0058] An opening (323) may be formed in the base portion (321). A plurality of openings (323) may be formed in the base portion (321), and may be provided so that the extinguishing material inside the extinguishing capsule (31) can flow to the electrode assembly (1), as described above. The opening (323) may have an arc shape with a predetermined width. A plurality of openings (323) may be provided in a shape spaced apart from each other in the circumferential direction. For example, four openings (323) having an arc shape may be provided spaced apart from each other at equal intervals in the circumferential direction. In this case, the plurality of openings (323) spaced apart from each other may have a shape that surrounds a protrusion (322) at the center of the base portion (321). A bridge portion (324) connecting an edge portion and a center portion of the base portion (321) may be formed between adjacent openings (323). When four openings (323) spaced apart from each other are provided, four bridge sections (324) can be provided correspondingly. The bridge sections (324) can be positioned between the melting sections (313) that are spaced apart from each other, which will be described later.

[0059] The protrusion (322) may be formed to protrude upward at a predetermined height from the central portion of the base portion (321). The protrusion (322) may be electrically connected to the electrode assembly (1). The protrusion (322) may be connected by penetrating into the through hole (311) of the digestive capsule (31) described later. The protrusion (322) may be in contact with the vent cover (20).

[0060] The digestion capsule (31) may be provided to accommodate a digestion substance to be injected into the electrode assembly (1). The digestion capsule (31) may be provided with a receiving space (314) for receiving the digestion substance, and the digestion substance received in the receiving space (314) may be provided to be injected into the electrode assembly (1) when an environment higher than a preset temperature is generated.

[0061] The digestive capsule (31) can be coupled to a support frame (32) and supported by the support frame (32). The digestive capsule (31) is formed in an overall circular shape corresponding to the shape of the cylindrical can housing (3), but as described above, a through hole (311) through which a protrusion (322) of the support frame (32) passes is formed in the central portion of the digestive capsule (31), so that the digestive capsule (31) can have a ring-shaped or donut-shaped shape.

[0062] The digestive capsule may include a housing portion (312) and a melting portion (313).

[0063] The housing portion (312) may be provided to form a receiving space (314) for receiving a extinguishing agent. The housing portion (312) forms the overall appearance of the extinguishing capsule (31) and may have a circular ring shape with a receiving space (314) formed therein. The upper surface of the housing portion (312) may face the vent cover (20). A portion of the lower surface of the housing portion (312) may be received and supported by the support frame (32), and the remaining portion may be provided as a melting portion (313) that is exposed to face the electrode assembly (1) through an opening (323) of the support frame (32).

[0064] At least a portion of the housing portion (312) may be formed to be inclined. Specifically, the bottom surface (3121) of the housing portion (312) surrounding the melting portion (313) may be inclined so that the height thereof gradually decreases in the direction toward the melting portion (313). By adopting this configuration, when the melting portion (313) is melted, the extinguishing agent can more easily flow downward toward the electrode assembly (1).

[0065] The melting portion (313) may be provided to melt at a preset temperature or higher and to inject the extinguishing agent into the electrode assembly (1). The melting portion (313) may be formed on the bottom surface of the housing portion (312). The melting portion (313) may have a shape that protrudes downward from the bottom surface of the housing portion (312). The melting portion (313) may extend from the housing portion (312), and the melting portion (313) and the housing portion (312) may be formed integrally, for example. The melting portion (313) may be formed of a material that melts at a preset reference temperature so as to melt at a preset temperature or higher and to inject the extinguishing agent in the internal storage space (314) of the housing portion (312).

[0066] The molten portion (313) protruding from the bottom surface of the housing portion (312) can be inserted into the opening (323) of the support frame (32). In this case, the molten portions (313) can be formed in a plurality corresponding to the openings (323) of the support frame (32), and similarly, a plurality of them can be positioned spaced apart from each other along the circumferential direction. The molten portions (313) can be formed in an arc shape having a predetermined width. For example, four molten portions (313) having an arc shape can be spaced apart at equal intervals along the circumferential direction and combined in a form in which they are each 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 digestive capsule (31) can correspond to each other. The above-described bridge portions (324) of the support frame (32) can be combined in the space between the adjacent molten portions (313).

[0067] Figures 8 and 9 illustrate a vent cover (20) of a top cap assembly according to Embodiment 1 of the present invention. Figure 8 is a plan view of the vent cover (20) of the top cap assembly according to Embodiment 1 of the present invention, and Figure 9 is a cross-sectional view taken along line cc illustrated in Figure 8.

[0068] As described above, the vent cover (20) may be provided to rupture at a pressure exceeding a preset value when gas is generated in the electrode assembly (1) due to a heat issue or the like, thereby discharging the internal gas to the outside. The vent cover (20) is positioned between the top cap (10) and the extinguishing module (30), and may be provided with a plurality of notches for easy rupture.

[0069] Referring to FIGS. 8 and 9, the vent cover (20) is formed in the shape of a circular plate to cover the digestion module (30), and a curved portion (21) may be formed at the edge. In this case, the vent cover (20) may have a shape that surrounds the digestion capsule (31) of the digestion module (30).

[0070] The curved portion (21) of the vent cover (20) can surround the fire capsule (31) of the fire extinguishing module (30). By adopting this configuration, not only the structural stability of the fire extinguishing capsule (31) is improved, but also the stability of the electrical connection between the support frame (32) coupled with the fire extinguishing capsule (31) and the vent cover (20) can be improved. The end of the curved portion (21) of the vent cover (20) can have a shape that is curved in a direction inserted into the space between the fire extinguishing capsule (31) and the support frame (32).

[0071] Example 2

[0072] Figures 10 and 11 illustrate a support frame (32) of a digestion module according to Embodiment 2 of the present invention. Figure 10 illustrates a plan view of a support frame (32) of a digestion module according to Embodiment 2 of the present invention, and Figure 11 is a cross-sectional view of the support frame (32) taken along line dd illustrated in Figure 10.

[0073] Embodiment 2 of the present invention may differ from Embodiment 1 in that a blocking plate (3221) is provided on the support frame. Except for the difference, it should be noted that the contents of the secondary battery according to Embodiment 1 of the present invention described above can be commonly applied to Embodiment 2 as well. Therefore, contents common to Embodiment 1 will be omitted as much as possible, and Embodiment 2 will be described focusing on the differences from Embodiment 1.

[0074] Referring to FIGS. 10 and 11, the protrusion (322) of the support frame (32) may include a blocking plate (3221) and a connecting frame (3222).

[0075] The blocking plate (3221) may be electrically connected to the electrode assembly (1). The blocking plate (3221) may be formed of a conductive material. The blocking plate (3221) may be electrically connected to the electrode assembly (1) to block overcurrent. The blocking plate (3221) may be a CID (Current Interrupt Device) filter that is provided to block current when a preset allowable current exceeds the current. The blocking plate (3221) may be electrically connected to the vent cover (20) described below by being in contact with it.

[0076] The connecting frame (3222) can extend vertically between the blocking plate (3221) and the base portion (321). The connecting frame (3222) can support the blocking plate (3221). The connecting frame (3222) can extend upward from the inner end of the base portion (321). The connecting frame (3222) can be formed of the same material as the base portion (321). The connecting frame (3222) can be formed integrally with the base portion (321). By employing this configuration, the thermal / electrical stability of the secondary battery can be further improved by blocking the generation of overcurrent as well as the spraying of the extinguishing powder.

[0077] In the above description, although the present invention has been described by limited embodiments and drawings, the above description is merely an example of the technical idea of ​​the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention.

[0078] Accordingly, the embodiments disclosed in the present invention are intended to illustrate, rather than limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical concepts within the scope equivalent thereto should be construed as being included within the scope of the present invention.

[0079]

[0080] [Explanation of symbols]

[0081] 1: Electrode assembly

[0082] 2: Top cap assembly

[0083] 3: Can housing

[0084] 4: Gasket

[0085] 10: Top cap

[0086] 20: Vent cover

[0087] 30: Digestion Module

[0088] 31: Digestive Capsule

[0089] 311: Through hole

[0090] 312: Housing Department

[0091] 3121: Bottom

[0092] 313: Melting zone

[0093] 314: Reception space

[0094] 32: Support frame

[0095] 321: Bass section

[0096] 322: Protrusion

[0097] 3221: Blocking plate

[0098] 3222: Connection Frame

[0099] 323: Opening

[0100] 324: Bridge Department

Claims

1. Cylindrical electrode assembly; a can housing for accommodating the electrode assembly; and A top cap assembly is included that is coupled to the can housing to cover the electrode assembly, The top cap assembly includes a fire extinguishing module having a fire extinguishing powder sprayed to the electrode assembly, and a top cap arranged on the upper side of the fire extinguishing module and electrically connected to the electrode assembly to enable electrical connection with the outside. The above digestion module, A digestive capsule is formed in which a receiving space for receiving digestive substances is formed, and at least one portion of the digestive capsule is formed to be meltable; and A secondary battery comprising a support frame coupled to the digestive capsule to support the digestive capsule and having an opening formed in one portion to allow the digestive material to flow to the electrode assembly.

2. In paragraph 1, The above support frame, a base portion supporting the above digestive capsule; and A secondary battery comprising a protrusion protruding upward at a predetermined height from the central portion of the base portion.

3. In paragraph 2, A secondary battery, wherein a through hole through which the protrusion penetrates is formed in the central portion of the digestive capsule.

4. In paragraph 2, The above protrusion is, A blocking plate electrically connected to the above electrode assembly to block overcurrent; and A secondary battery comprising a connecting frame extending vertically between the blocking plate and the base portion.

5. In paragraph 2, A secondary battery in which the above openings are formed in multiple numbers in the base portion.

6. In paragraph 5, A secondary battery, wherein a plurality of the above openings are spaced apart from each other along the circumferential direction on the base portion.

7. In paragraph 2, The above digestive capsules are, a housing portion forming the above-mentioned accommodation space; and A secondary battery comprising a melting portion formed on the lower surface of the housing portion and configured to melt at a preset temperature or higher and eject the extinguishing substance.

8. In paragraph 7, A secondary battery, wherein the above melting portion is provided to protrude downward from the bottom surface of the housing portion.

9. In paragraph 7, A secondary battery in which the bottom surface of the housing portion is formed to be inclined in a direction in which the height decreases toward the melting portion.

10. In paragraph 7, A secondary battery, wherein the above melting part is inserted into the above opening.

11. In paragraph 7, A plurality of the above openings are formed spaced apart from each other along the circumferential direction on the base portion, A secondary battery, wherein the above melting portions are spaced apart from each other in the circumferential direction on the bottom surface of the housing portion in a plurality corresponding to the position of the opening.

12. In a top cap assembly that is provided to be combined with a cylindrical electrode assembly, A digestive capsule in which a receiving space for receiving digestive substances is formed, at least one portion of which is formed to be meltable; A support frame coupled to the digestive capsule to support the digestive capsule and having an opening formed in one portion to allow the digestive material to flow to the electrode assembly; and A top cap assembly comprising a top cap arranged on the upper side of a combined upper limb support frame and a digestive capsule and electrically connected to the electrode assembly so as to enable electrical connection with the outside.

13. In paragraph 12, A top cap assembly further comprising a vent cover disposed between the top cap and the digestive capsule, configured to burst when a pressure exceeds a preset pressure to release gas, and having edges formed to be curved to surround the digestive capsule.

14. In a digestion module provided on the upper side of a cylindrical electrode assembly to eject digestive substances, A digestive capsule is formed in which a receiving space for receiving the digestive substance is formed, and at least one portion thereof is formed to be meltable; and A secondary battery digestion module comprising a support frame coupled to the digestion capsule to support the digestion capsule and having an opening formed in one portion to allow the digestion material to flow to the electrode assembly.

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