Electrode lead assembly, method for manufacturing electrode lead assembly, secondary battery, and method for manufacturing secondary battery

Abstract

The present invention relates to an electrode lead assembly, a method for manufacturing the electrode lead assembly, a secondary battery, and a method for manufacturing the secondary battery and, more particularly, to a secondary battery and a method for manufacturing the secondary battery, the secondary battery being provided with a foaming member having foamability by heat in a fluid movement path. An electrode lead assembly according to an embodiment of the present invention includes: an electrode lead; a lead film made of an insulating material and adhered to a part of the electrode lead; and a foaming member having foamability by heat, wherein a fluid movement path through which a fluid moves is formed between the electrode lead and the lead film, and the foaming member may be provided in the fluid movement path.

Description

Electrode lead assembly, method for manufacturing electrode lead assembly, secondary battery and method for manufacturing secondary battery

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0091268, filed July 10, 2024, and Korean Patent Application No. 10-2025-0091129, filed July 7, 2025, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to an electrode lead assembly, a method for manufacturing an electrode lead assembly, a secondary battery, and a method for manufacturing a secondary battery, and more specifically, to an electrode lead assembly in which a foam member having heat-induced foaming properties is provided in a fluid movement path, a method for manufacturing such an electrode lead assembly, a secondary battery, and a method for manufacturing such a secondary battery.

[0005] In recent years, rising energy prices due to the depletion of fossil fuels and growing concerns about environmental pollution have made the demand for eco-friendly alternative energy sources essential for future living. Research is continuing into various power generation technologies, such as solar, wind, and tidal power. Furthermore, significant interest is being focused on power storage devices, such as batteries, to more efficiently utilize the generated electricity.

[0006] Moreover, with the technological development and increasing demand for battery-powered electronic mobile devices and electric vehicles, the demand for batteries as an energy source is rapidly increasing, and accordingly, much research is being conducted on batteries that can meet various needs.

[0007] Batteries that store electrical energy can generally be divided into primary and secondary batteries. Primary batteries are disposable, consumable batteries, whereas secondary batteries are rechargeable batteries manufactured using materials capable of repeatable oxidation and reduction processes between current and a substance. In other words, when current causes a reduction reaction in a material, the battery is charged, and when an oxidation reaction occurs in the material, the battery is discharged. This repeated charge-discharge cycle generates electricity.

[0008] Secondary batteries can be classified into cylindrical cells, pouch cells, and prismatic cells based on their shape. Among them, pouch cells can be manufactured by housing an electrode assembly in which a positive electrode, a negative electrode, a separator, etc. are laminated inside a pouch, and sealing the outer part of the pouch.

[0009] Meanwhile, the electrolyte may be contained within the pouch of the pouch cell together with the electrode assembly. At this time, residual moisture in the electrolyte or moisture that has penetrated from the outside may react with the lithium salt to generate HF (hydrogen fluoride) inside the pouch of the pouch cell, and gases such as carbon dioxide, carbon monoxide, ethylene, and methane may be generated due to the decomposition of the electrolyte. Furthermore, depending on the material of the positive electrode included in the electrode assembly of the pouch cell, additional hydrogen and HF may be generated, which may lead to overheating due to overcharging and internal short-circuiting during the charging and discharging processes. Consequently, a large amount of gas may be generated within the pouch. This gas may increase the pressure within the pouch, and the increased pressure may cause the pouch to expand, resulting in swelling, or even bursting. Therefore, the pouch cell requires a structure capable of efficiently discharging the gas within the pouch to prevent the pouch from bursting due to internal pressure.

[0010] The object of the present invention is to provide an electrode lead assembly having a structure capable of efficiently discharging gas inside a pouch to the outside, a method for manufacturing such an electrode lead assembly, a secondary battery, and a method for manufacturing such a secondary battery.

[0011] An electrode lead assembly according to the present invention comprises: an electrode lead; a lead film made of an insulating material and adhered to a portion of the electrode lead; and a foam member having foaming properties due to heat, wherein a fluid path through which a fluid moves is formed between the electrode lead and the lead film, and the foam member can be provided in the fluid path.

[0012] The fluid path may include a first fluid path extending along the length direction of the electrode lead from one end of the lead film; and a second fluid path connected to the first fluid path and extending along the width direction of the electrode lead.

[0013] The above foam member may be provided in the first fluid movement path.

[0014] The above foam member can be foamed at a temperature of 150°C or higher.

[0015] The above foam member has a sheet shape and can be attached to one surface of the electrode lead.

[0016] The above foam member may include a shell composed of a polymer material and expanding when heated; and a foamable material contained in the shell and foaming when heated.

[0017] The above electrode lead assembly may further include a coating layer that coats the foam member on the electrode lead.

[0018] The above electrode lead assembly may further include a pad-shaped member having one surface bonded to the electrode lead.

[0019] The above fluid movement path can be formed between the pad-shaped member and the lead film.

[0020] A method for manufacturing an electrode lead assembly according to the present invention comprises a foam member arrangement step of arranging a foam member having heat-expandable properties on one side of an electrode lead; and a film attachment step of attaching a lead film made of an insulating material to the electrode lead on which the foam member is arranged, wherein in the film attachment step, the lead film is attached only to a portion of the electrode lead, and a fluid path through which a fluid moves can be formed between the lead film and the electrode lead.

[0021] In the above film attachment step, the foam member can be adhered to the electrode lead by the lead film.

[0022] In the above film attachment step, the lead film can be attached to the electrode lead such that one end thereof is arranged parallel to one end of the foam member.

[0023] In the above foam member arrangement step, the foam member can be attached to one side of the electrode lead.

[0024] In the above foam member arrangement step, the foam member can be coated on one surface of the electrode lead.

[0025] The above electrode lead assembly manufacturing method is performed before the foam member arrangement step, and may further include a pad arrangement step of arranging a pad-shaped member on one surface of the electrode lead.

[0026] In the above foam member arrangement step, the foam member can be arranged on one side of the pad-shaped member.

[0027] In the above film attachment step, the foam member can be adhered to the pad-shaped member by the lead film.

[0028] A secondary battery according to the present invention comprises: an electrode assembly including a negative electrode, a positive electrode, and a separator; an outer case for accommodating the electrode assembly; an electrode lead electrically connected to the electrode assembly and protruding to the outside of the outer case; and a lead film adhered to a portion of the electrode lead so as to insulate the electrode lead from the outer case, wherein a fluid path through which a gas generated during charging and discharging of the electrode assembly moves is formed between the electrode lead and the lead film, and a foam member having a foaming property due to heat may be provided in the fluid path.

[0029] The foam member may be positioned adjacent to the internal space of the outer material that accommodates the electrode assembly in the fluid passage.

[0030] The fluid path may include a first fluid path adjacent to the internal space of the outer material and extending along the length direction of the electrode lead; and a second fluid path connected to the first fluid path and extending along the width direction of the electrode lead.

[0031] The above foam member may be provided in the first fluid movement path.

[0032] A method for manufacturing a secondary battery according to the present invention comprises: a foam member arrangement step of arranging a foam member having a foaming property due to heat on one side of an electrode lead; a film attachment step of attaching a lead film made of an insulating material to the electrode lead on which the foam member is arranged; a connection step of electrically connecting an electrode assembly including a negative electrode, a positive electrode, and a separator, which is arranged inside an outer material, to the electrode lead; and a sealing step of sealing the inside of the outer material by adhering the outer material and the lead film, wherein in the film attachment step, the lead film is attached only to a part of the electrode lead, so that a fluid movement path through which a gas generated during charging and discharging of the electrode assembly moves can be formed between the lead film and the electrode lead.

[0033] The above sealing step includes a step of applying heat and pressure to the outer material and the lead film, and at least a portion of the foam member can be foamed by the heat applied in the sealing step.

[0034] According to an electrode lead assembly according to one embodiment of the present invention, a fluid path is formed between an electrode lead and a lead film, and a foaming member having a foaming property due to heat can be provided in the fluid path. Such an electrode lead assembly is a component of a battery cell and can be electrically connected to an electrode assembly. When the battery cell is charged and discharged, heat is generated, and the foaming member can foam between the electrode lead and the lead film. In this case, since the fluid path is expanded, the internal gas of the battery cell can be smoothly discharged, thereby delaying or preventing damage to the exterior material of the battery cell due to an increase in internal pressure.

[0035] Meanwhile, the effects according to the present invention are not limited to the contents exemplified above, and more diverse effects are included in the present specification.

[0036] FIG. 1 is a cross-sectional view of an electrode lead assembly according to one embodiment of the present invention.

[0037] Fig. 2 is a drawing for explaining the shape of the fluid movement path in the electrode lead assembly of Fig. 1.

[0038] FIG. 3 is a drawing for explaining the electrode lead assembly of FIG. 1 in which the foam member is placed only in a part of the fluid movement path.

[0039] Fig. 4 is a cross-sectional view for explaining the structure of the foam member provided in the electrode lead assembly of Fig. 1.

[0040] Fig. 5 is a cross-sectional view showing an electrode lead assembly of Fig. 1 additionally provided with a pad-shaped member.

[0041] Fig. 6 is a cross-sectional view showing a coating layer formed on the electrode lead assembly of Fig. 1.

[0042] Figure 7 is a cross-sectional view of an electrode lead assembly according to another embodiment of the present invention.

[0043] Figure 8 is a flowchart of a method for manufacturing an electrode lead assembly according to the present invention.

[0044] Figure 9 is a perspective view schematically illustrating a secondary battery according to the present invention.

[0045] Fig. 10 is a cross-sectional view schematically illustrating a portion of a cross-section taken along line A-A' of Fig. 1.

[0046] Figure 11 is a plan view schematically illustrating a portion of a secondary battery according to the present invention.

[0047] Figure 12 is a plan view schematically illustrating a secondary battery according to the present invention in which a foam member is placed only in a part of a fluid movement path.

[0048] Figure 13 is a flowchart of a secondary battery manufacturing method according to the present invention.

[0049] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0050] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0051] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0052] Hereinafter, with reference to the drawings, the electrode lead assembly, the manufacturing method of the electrode lead assembly, the secondary battery, and the manufacturing method of the secondary battery according to the present invention will be described.

[0053] Electrode lead assembly

[0054] Fig. 1 is a cross-sectional view of an electrode lead assembly according to one embodiment of the present invention. Fig. 2 is a drawing for explaining the shape of a fluid passage in the electrode lead assembly of Fig. 1. Fig. 3 is a drawing for explaining a state in which a foam member is arranged only in a portion of a fluid passage in the electrode lead assembly of Fig. 1.

[0055] Referring to FIGS. 1 to 3, an electrode lead assembly (10) according to one embodiment of the present invention may include an electrode lead (11), a lead film (12) made of an insulating material and adhered to a portion of the electrode lead (11), and a foam member (13) having foaming properties due to heat. A fluid path (S) through which a fluid moves is formed between the electrode lead (11) and the lead film (12), and the foam member (13) may be provided in the fluid path (S).

[0056] This electrode lead assembly (10) is a component of a secondary battery and can be electrically connected to an electrode assembly constituting the secondary battery. When the secondary battery is charged and discharged, heat is generated, and the foam member (13) that receives the heat can foam between the electrode lead (11) and the lead film (12). In this case, since the fluid passage (S) expands due to pressure, the internal gas of the secondary battery can be smoothly discharged through the expanded fluid passage (S). As a result, damage to the exterior material of the secondary battery due to an increase in the internal pressure of the secondary battery can be delayed or prevented.

[0057] The electrode lead (11) is electrically connected to the electrode assembly of the secondary battery, and a portion thereof may protrude outside the outer casing of the secondary battery. By virtue of the electrode lead protruding outside the outer casing, the secondary battery can provide electrical energy to the outside. In other words, the electrode lead (11) may be a conductive terminal.

[0058] The lead film (12) may be a sheet that covers the electrode lead (11) so that the outer material of the secondary battery and the electrode lead (11) are insulated from each other. This lead film (12) may be placed on both sides of the electrode lead (11) to cover the electrode lead (11). The lead films (12) may be configured as a pair to cover each side of the electrode lead (11).

[0059] This lead film (12) may be composed of an insulating material. In particular, the lead film (12) may be composed of a semi-permeable material that does not allow the electrolyte of the secondary battery to pass through, but allows the gas generated inside the secondary battery to pass through. For example, the lead film (12) may be a semi-permeable membrane composed of a resin series such as PP, PET, PE, etc.

[0060] Meanwhile, the secondary battery to which the electrode lead assembly (10) is connected may generate gas as charging and discharging are repeated, which may increase the pressure inside the outer case. If the pressure inside the outer case increases excessively, damage to the outer case may occur, causing the secondary battery to lose its function.

[0061] An electrode lead assembly (10) according to one embodiment of the present invention may be coupled to a secondary battery and may have a structure that easily discharges pressure generated internally during charging and discharging of the secondary battery through a fluid passage (S). Therefore, the electrode lead assembly (10) according to one embodiment of the present invention can prevent the internal pressure of the secondary battery from increasing excessively.

[0062] Meanwhile, the fluid movement path (S) may be a portion where the electrode lead (11) and the lead film (12) are not adhered to each other. Specifically, when the lead film (12) is adhered to the electrode lead (11), it may be adhered only to a portion of the electrode lead (11). That is, the portion where the lead film (12) and the electrode lead (11) are not adhered may become a fluid movement path (S) through which the fluid can move.

[0063] This fluid movement path (S) may include a first fluid movement path (S1) extending along the length direction of the electrode lead (11) from one end of the lead film (12) and a second fluid movement path (S2) connected to the first fluid movement path (S1) and extending along the width direction of the electrode lead (11). That is, the fluid movement path (S) may have an approximate “T” or “ㅠ” shape. At this time, one end of the first fluid movement path (S1) may be in contact with one end of the lead film (12), and the other end of the first fluid movement path (S1) may be in contact with the second fluid movement path (S2).

[0064] Meanwhile, the foam member (13) can be placed at various locations in the fluid movement path (S). For example, the foam member (13) can be placed at equal intervals from one end to the other end of the fluid movement path (S).

[0065] In addition, the foam member (13) may be placed in the first fluid passage (S1). One end of the first fluid passage (S1) is in contact with one end of the lead film (12), and one end of the lead film (12) may be in contact with the internal space of the secondary battery. In this case, when the secondary battery is charged and discharged, the foam member (13) may foam in an area adjacent to the internal space of the secondary battery. Therefore, the internal gas of the secondary battery can easily flow into the expanded fluid passage (S) due to the foaming of the foam member (13), thereby efficiently discharging the internal gas of the secondary battery.

[0066] Fig. 4 is a cross-sectional view for explaining the structure of the foam member provided in the electrode lead assembly of Fig. 1.

[0067] Referring to Fig. 4, the foam member (13) is composed of a polymer material and may include a shell (13a) that expands upon heating and a foamable material (13b) contained in the shell (13a) that foams upon heating. The shell (13a) is a material that expands upon receiving heat, and various types of polymer materials may be used for the shell. In addition, the foamable material (13b) is a material that foams upon receiving heat, and a foaming agent that foams at a temperature of 150°C or higher may be used for the shell.

[0068] Meanwhile, the foam member (13) having a spherical shape can be bonded to the electrode lead (11) in various ways. For example, the foam member (13) can be attached to the electrode lead (11) by an adhesive, and an adhesive layer in which the adhesive is cured can be formed between the foam member (13) and the electrode lead (11).

[0069] Fig. 5 is a cross-sectional view showing an electrode lead assembly of Fig. 1 additionally provided with a pad-shaped member.

[0070] Referring to FIG. 5, an electrode lead assembly (10) according to one embodiment of the present invention may further include a pad-shaped member (15) having one surface bonded to an electrode lead (11). At this time, a fluid movement path (S) may be formed between the pad-shaped member (15) and the lead film (11).

[0071] Specifically, the aforementioned fluid movement path (S) is provided on the upper side of the pad-shaped member (15), and a foam member (13) that foams due to heat can be provided in at least a portion of the fluid movement path (S). When the foam member (13) is foamed, the fluid movement path (S) formed between the pad-shaped member (15) and the lead film (11) can expand.

[0072] Meanwhile, when looking down at the pad-shaped member (15) from above, the pad-shaped member (15) may have a roughly "T" or "ㅠ" shape. However, this is merely an example, and the pad-shaped member may have various shapes.

[0073] In addition, the fluid movement path (S) formed on the upper side of the pad-shaped member (15) may have the same shape as the geometry of the pad-shaped member (15). For example, when the pad-shaped member (15) has a "T" or "ㅠ" shape, the fluid movement path (S) may also have a "T" or "ㅠ" shape. In addition, one end of the pad-shaped member (15) may touch one end of the lead film (12).

[0074] The foam member (13) is provided in a fluid movement path (S) provided on the upper side of the pad-shaped member (15), and the foam member (13) can be provided in various areas on the upper side of the pad-shaped member (15). For example, the foam member (13) can be provided on all areas on the upper side of the pad-shaped member (15) having a "T" or "ㅠ" shape. In addition, the foam member (13) can be provided on only some areas of the pad-shaped member (15).

[0075] Fig. 6 is a cross-sectional view showing a coating layer formed on the electrode lead assembly of Fig. 1.

[0076] Referring to FIG. 6, an electrode lead assembly (10) according to one embodiment of the present invention may include a coating layer (14) that coats a foam member (13) on an electrode lead (11). This coating layer (14) may be formed in various ways. For example, the coating layer (14) may be formed by curing a liquid resin, and a plurality of foam members (13) may be coated on one surface of the electrode lead (11).

[0077] An electrode lead assembly (10) according to one embodiment of the present invention has a coating layer (14) as described above, so that even when an impact is applied to the electrode lead assembly (10) or the electrode lead assembly (10) moves, the foam member (13) can be fixed to a predetermined position in the fluid movement path (S).

[0078] Figure 7 is a cross-sectional view of an electrode lead assembly according to another embodiment of the present invention.

[0079] Referring to FIG. 7, in an electrode lead assembly (10`) according to another embodiment of the present invention, a foam member (13`) has a sheet shape and can be attached to one surface of the electrode lead (11`).

[0080] An electrode lead assembly (10`) according to another embodiment of the present invention may include an electrode lead (11`), a lead film (12`), and a foam member (13`). A fluid passage (S`) is formed between the electrode lead (11`) and the lead film (12`), and the foam member (13`) may be provided in the fluid passage (S`).

[0081] The foam member (13`) has a sheet shape and can be attached to one surface of the electrode lead (11`). Specifically, the foam member (13`) may include a sheet-shaped shell having a hollow space therein and a foaming material accommodated in the hollow space inside the shell. The shell is a material that expands when heated, and various types of polymer materials may be used therein. In addition, the foaming material is a material that foams when heated, and a foaming agent that foams at a temperature of 150°C or higher may be used therein. In addition, an adhesive layer may be formed between the shell and the electrode lead (11`).

[0082] Meanwhile, the sheet-shaped foam member (13`) may have various thicknesses. For example, the sheet-shaped foam member (13`) may have a thickness of 40 um to 60 um. In particular, the sheet-shaped foam member (13`) may have a thickness of 50 um. When the sheet-shaped foam member (13`) has a thickness of 50 um, it has an appropriate explosive power, and thus can expand the fluid passage (S`) without damaging the electrode lead (11`) and the lead film (12`).

[0083] Electrode lead assembly manufacturing method

[0084] Figure 8 is a flowchart of a method for manufacturing an electrode lead assembly according to the present invention.

[0085] Referring to FIG. 8, the method for manufacturing an electrode lead assembly according to the present invention may include a foam member arrangement step (S20) of arranging a foam member (13) having a foaming property due to heat on one side of an electrode lead (11), and a film attachment step (S30) of attaching a lead film (12) made of an insulating material to the electrode lead (11) on which the foam member (13) is arranged. In the film attachment step (S30), the lead film (12) is attached only to a portion of the electrode lead (11), and a fluid path (S) through which a fluid moves may be formed between the lead film (12) and the electrode lead (11).

[0086] An electrode lead assembly (10) manufactured by a method for manufacturing an electrode lead assembly according to the present invention has a fluid path (S) through which a fluid moves between an electrode lead (11) and a lead film (12), and a thermally expandable foam member (13) may be provided in the fluid path (S). This electrode lead assembly (10) is a component of a secondary battery and may be electrically connected to an electrode assembly constituting the secondary battery. When the secondary battery is charged and discharged, heat is generated, and the foam member (13) that receives the heat may foam between the electrode lead (11) and the lead film (12). In this case, since the fluid path (S) expands due to pressure, the internal gas of the secondary battery can be smoothly discharged through the expanded fluid path (S). As a result, damage to the exterior material of the secondary battery due to an increase in the internal pressure of the secondary battery can be delayed or prevented.

[0087] The foam member arrangement step (S20) is a step of arranging a foam member (13) having heat-induced foaming properties on one side of the electrode lead (11), and may be a step of arranging the foam member (13) on the upper surface of the electrode lead (11). The foam member (13) arranged on the upper surface of the electrode lead (11) can be adhered to the upper surface of the electrode lead (11) by the film attachment step (S30).

[0088] In the foam member arrangement step (S20), the foam member (13) can be attached to one side of the electrode lead (11). The attachment of the foam member (13) and the electrode lead (11) can be performed in various ways. For example, the foam member arrangement step (S30) can be a step of forming an adhesive layer on one side of the electrode lead (11) and then placing the foam member (13) on the adhesive layer.

[0089] In addition, in the foam member arrangement step (S20), the foam member (13) can be coated on one side of the electrode lead (11). Various methods can be used for coating the foam member (13). For example, a coating layer (14) in which a liquid resin is cured is formed in the fluid passage (S), and this coating layer (14) can coat a plurality of foam members (13) on one side of the electrode lead (11).

[0090] The film attachment step (S30) is a step of attaching a lead film (12) made of an insulating material to the electrode lead (11). The lead film (12) can be attached so as to cover at least a portion of the electrode lead (11). The lead film (12) is a film that prevents the electrode lead (11) from directly contacting the outer material of the secondary battery, and can be an insulating tape having an adhesive surface. At this time, the adhesive surface of the lead film (12) can be attached to the electrode lead (11).

[0091] The method for manufacturing an electrode lead assembly according to the present invention is performed before the foam member arrangement step (S20), and may further include a pad arrangement step (S10) of arranging a pad-shaped member (15) on one surface of an electrode lead (11). At this time, in the foam member arrangement step (S20), the foam member (13) may be arranged on one surface of the pad-shaped member (15). In addition, in the film attachment step (S30), the foam member (13) may be adhered to the pad-shaped member (15) by the lead film (12).

[0092] Meanwhile, in the electrode lead manufacturing method (10) according to the present invention, the foam member provided between the electrode lead and the lead film may be a sheet-shaped foam member (13`) as illustrated in Fig. 7. In this case, in the film attachment step (S30), the lead film (12`) may be attached to the electrode lead (11`) such that one end thereof is arranged parallel to one end of the sheet-shaped foam member (13`).

[0093] secondary battery

[0094] Fig. 9 is a perspective view schematically illustrating a secondary battery according to the present invention, and Fig. 10 is a cross-sectional view schematically illustrating a portion of a cross-section taken along line A-A' of Fig. 1. Fig. 11 is a plan view schematically illustrating a portion of a secondary battery according to the present invention.

[0095] Referring to FIGS. 9 to 11, a secondary battery (100) according to the present invention may include an electrode assembly (110) including a negative electrode, a positive electrode, and a separator, an outer case (120) accommodating the electrode assembly (110), an electrode lead (130) electrically connected to the electrode assembly (110) and protruding outward from the outer case (120), and a lead film (140) adhered to a portion of the electrode lead (130) so that the electrode lead (130) is insulated from the outer case (120). Here, a fluid path (S) through which a gas generated during charging and discharging of the electrode assembly (110) moves is formed between the electrode lead (130) and the lead film (140), and a foam member (150) having foaming properties due to heat may be provided in this fluid path (S).

[0096] In this case, the foam member (150) foams by receiving heat generated during charging and discharging of the electrode assembly between the electrode lead (130) and the lead film (140), thereby expanding the fluid path (S) through which the gas inside the outer material (120) moves. Accordingly, the gas inside the outer material (120) moves through the expanded fluid path (S) and is discharged to the outside of the outer material (120), thereby delaying or preventing rupture of the outer material (120) due to an increase in internal pressure.

[0097] The secondary battery (100) may have a form in which the electrode assembly (110) is housed within an outer case (120). For example, the secondary battery (100) according to the present invention may refer to a pouch-type secondary battery among various forms of secondary batteries capable of being charged and discharged. This is merely one example, and the shape of the secondary battery (100) may vary.

[0098] The electrode assembly (110) may include an anode, a cathode, and a separator. Here, the separator may be placed between the anode and the cathode to physically separate the anode and the cathode. The electrode assembly (110) may be in the form of a stacked anode, a cathode, and a separator, or in the form of a jelly-roll in which the anode, the cathode, and the separator are wound.

[0099] The electrode assembly (110) may be accommodated inside an outer material (120). The outer material (120) may be a pouch-shaped outer material including an inner layer, a metal layer, and an outer layer. Here, the inner layer of the pouch-shaped outer material may be bonded to each other by heat and pressure to seal the internal space (A) of the outer material (120). That is, after the outer material (120) accommodates the electrode assembly (110) inside, the inner layer may be sealed by heat and pressure. Meanwhile, the metal layer may mainly be made of Al, STS, or the like, and the outer layer may be composed of a material having insulating properties.

[0100] The inner layer capable of sealing the outer material (120) through sealing may be made of one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, Teflon, and glass fiber. In particular, a polyolefin resin such as polypropylene (PP) or polyethylene (PE) may be mainly used.

[0101] The secondary battery (100) may include an electrode lead (130). The electrode lead (130) may be electrically connected to the electrode assembly (110) and may be arranged to protrude outside the outer case (120). The secondary battery (100) may provide electrical energy to the outside by the electrode lead (130) protruding outside the outer case (120). Therefore, the electrode lead (130) may be a conductor.

[0102] The lead film (140) can cover the electrode lead (130) so that the outer material (120) and the electrode lead (130) are insulated from each other. Specifically, the lead film (140) can be placed on both sides of the electrode lead (130) to cover the electrode lead (130). The lead films (140) can be configured as a pair and placed on each side of the electrode lead (130).

[0103] This lead film (140) may be composed of an insulating material. In particular, the lead film (140) may be composed of a semi-permeable material that does not allow the electrolyte of the secondary battery to pass through, but allows the gas generated inside the secondary battery to pass through. For example, the lead film (140) may be a semi-permeable membrane composed of a resin series such as PP, PET, PE, etc.

[0104] Meanwhile, as the secondary battery (100) is repeatedly charged and discharged, gas may be generated, which may increase the pressure inside the outer case (120). If the pressure inside the outer case (120) increases excessively, the outer case (120) may rupture, etc., causing the secondary battery (100) to lose its function.

[0105] Specifically, an electrolyte may be accommodated together with an electrode assembly (110) inside the outer case (120) of the secondary battery (100). At this time, residual moisture of the electrolyte inside the outer case (120) of the secondary battery (100) or moisture that has penetrated from the outside may react with a lithium salt to generate HF, and gases such as carbon dioxide, carbon monoxide, ethylene, and methane may be generated due to decomposition of the electrolyte.

[0106] In addition, depending on the material of the positive electrode included in the electrode assembly (110) of the secondary battery (100), hydrogen and HF may be additionally generated, which may result in overheating due to overcharging and internal short circuit during the charging and discharging process. Accordingly, a large amount of gas may be generated inside the outer case (120). The pressure inside the outer case increases due to such gas, and the increased pressure may cause a swelling phenomenon in which the outer case (120) swells or a bursting phenomenon in which a portion of the outer case (120) bursts.

[0107] The secondary battery (100) according to the present invention may include a configuration capable of discharging gas inside the outer case (120) to the outside of the outer case (120) to prevent rupture of the outer case (120). Referring to FIGS. 10 and 11, a fluid movement path (S) may be formed between the electrode lead (130) and the lead film (140) in the secondary battery (100) according to the present invention.

[0108] These fluid movement paths (S) can be formed before gas is generated inside the secondary battery (100) due to repeated charging and discharging. For example, the fluid movement path (S) can be a portion where the electrode lead (130) and the lead film (140) are not bonded to each other. Specifically, when the lead film (140) is bonded to the electrode lead (130), it can be bonded only to a portion of the electrode lead (130). That is, the area where the lead film (140) and the electrode lead (130) are not bonded can become a fluid movement path (S) through which gas can move.

[0109] Additionally, the fluid movement path (S) can be formed by foaming the foam member (150). Specifically, the foam member (150) provided between the electrode lead (130) and the lead film (140) can be foamed by heat applied during sealing of the outer material (120). In this case, the bond between one surface of the electrode lead (130) and the lead film (140) is released, forming an empty space, and this empty space can become the fluid movement path (S).

[0110] The fluid movement path (S) may be provided so that one end thereof is in communication with the internal space (A) of the outer casing (120). Accordingly, when gas is generated inside the outer casing (120) of the secondary battery (100), the gas can move through the fluid movement path (S). The other end of the fluid movement path (S) is not exposed to the external space of the outer casing (120), and the gas that has moved to the other end of the fluid movement path (S) can pass through the lead film (140) and be discharged to the outside of the outer casing (120).

[0111] That is, gas can be permeated through the lead film (140). Specifically, the lead film (140) can be formed so that only gas can permeate the lead film (140), and liquids and solids cannot move through the lead film (140). In this case, the gas can permeate the lead film (140) by diffusion through movement at the molecular level.

[0112] Accordingly, the secondary battery (100) according to the present invention may be provided with a fluid passage (S) that can discharge internal gas between the electrode lead (130) and the lead film (140) by means of a foam member (150). In this case, the internal gas of the outer material (120) is discharged to the outside through the fluid passage (S) and the lead film (140), thereby delaying or preventing rupture of the outer material (120) due to an increase in internal pressure.

[0113] Meanwhile, the foam member (150) may be placed at various locations between the electrode lead (130) and the lead film (140). For example, the foam member (150) may be placed in a fluid passage (S) formed between the electrode lead (130) and the lead film (140). At this time, the foam member (150) may be placed at equal intervals from one end of the fluid passage (S) to the other end.

[0114] In addition, the foam member (150) may be arranged parallel to one end of the lead film (140). Here, one end of the lead film (140) may be one end that touches the internal space (A) of the outer material (120). In this way, when the foam member (150) is arranged on one end of the lead film (140), the fluid passage (S) formed by the foaming of the foam member (150) may be communicated with the internal space (A) of the outer material (120). In this case, the gas currently trapped in the internal space (A) of the outer material (120) can easily flow into the fluid passage (S), thereby efficiently discharging the internal gas of the outer material (120).

[0115] Meanwhile, the foam member (150) may have various shapes and structures. For example, the foam member (150) may be provided in at least a portion of the fluid passage (S) and may have a sheet shape that is bonded to one surface of the electrode lead (130). In this case, an adhesive layer may be formed between the foam member (150) and the electrode lead (130). The sheet-shaped foam member (150) may have the same structure as the foam member (13') illustrated in FIG. 7 described above.

[0116] Figure 12 is a plan view schematically illustrating a secondary battery according to the present invention in which a foam member is placed only in a part of a fluid movement path.

[0117] Referring to Fig. 12, the foam member (150) may be placed in a portion adjacent to the internal space (A) of the exterior material (120) among the fluid passages (S). In this case, when the foam member (150) is foamed, the inlet portion through which the internal gas of the exterior material (120) flows into the fluid passage (S) expands, so that the internal gas can be effectively introduced into the fluid passage (S).

[0118] Specifically, the fluid movement path (S) may include a first fluid movement path (S1) adjacent to the internal space (A) of the outer material (120) and extending along the length direction of the electrode lead (130), and a second fluid movement path (S2) connected to the first fluid movement path (S1) and extending along the width direction of the electrode lead (130). Here, the foam member (150) may be provided in the first fluid movement path (S1).

[0119] The first fluid path (S1) and the second fluid path (S2) can be formed in various ways. For example, the fluid path (S) can have a roughly "T" or "ㅠ" shape. Among the "T" or "ㅠ" shaped fluid paths (S), a relatively narrow leg portion (S1) can become the first fluid path (S1), and the upper plate portion (S2) of the fluid path (S) can become the second fluid path (S2).

[0120] Meanwhile, the foam member (150) may have a spherical shape. Specifically, the foam member (150) may be composed of a polymer material and may include a spherical shell that expands upon heating and a foaming material contained within the shell that foams upon heating. This structure of the foam member (150) may be identical to the structure of the foam member (13) illustrated in FIG. 4.

[0121] The shell is a material that expands when heated, and various types of polymer materials can be used. Furthermore, the foaming material is a material that foams when heated, and a foaming agent that foams at temperatures above 150°C can be used.

[0122] Meanwhile, the foam member (150) having a spherical shape can be coupled to the electrode lead (130) in various ways. For example, the foam member (150) can be attached to the electrode lead (130) by an adhesive, and an adhesive layer in which the adhesive is cured can be formed between the foam member (150) and the electrode lead (130).

[0123] In addition, the foam member (150) may be coated on one side of the electrode lead (130). For example, the foam member (150) may be coated on the electrode lead (130) using a thermosetting material such as resin. In this case, the cured resin may form a coating layer. The structure in which the foam member (150) is coated on the electrode lead (130) using the coating layer may be the same as the structure in which the foam member (13) illustrated in FIG. 6 is coated on the electrode lead (11) using the coating layer (14).

[0124] Meanwhile, the secondary battery (100) may further include a pad-shaped member having one side bonded to the electrode lead (130). The aforementioned fluid movement path (S) is provided on the upper side of the pad-shaped member, and a foaming member (150) that foams by heat may be provided in at least a portion of the fluid movement path (S).

[0125] The above structure in which a fluid movement path (S) is provided on the upper side of a pad-shaped member and a foam member (150) is provided on the fluid movement path (S) may be the same as the structure in which a fluid movement path (S) is provided on the upper side of a pad-shaped member (15) illustrated in FIG. 5 and a foam member (13) is provided on the fluid movement path (S).

[0126] When the foam member (150) is foamed, the fluid passage (S) formed between the pad-shaped member and the lead film (140) expands, and the gas trapped in the internal space (A) of the outer material (120) can be discharged to the outside of the outer material (120) through the expanded fluid passage (S).

[0127] Meanwhile, when looking down at the pad-shaped member from above, the pad-shaped member may have a shape roughly like a "T" or "ㅠ". However, this is merely an example, and the pad-shaped member may have various shapes.

[0128] Additionally, the fluid passage (S) formed on the upper side of the pad-shaped member may form a fluid passage (S) having the same shape as the geometry of the pad-shaped member. For example, if the pad-shaped member has a "T" or "ㅠ" shape, the fluid passage (S) may also have a "T" or "ㅠ" shape.

[0129] In addition, one end of the pad-shaped member may touch one end of the lead film (140). In this case, at least a part of the pad-shaped member may touch the internal space (A) of the outer material (120). In this case, the gas flowing in the internal space (A) of the outer material (120) is easily introduced into the fluid passage (S) formed on the upper side of the pad-shaped member, thereby efficiently discharging the internal gas of the outer material (120).

[0130] As described above, the secondary battery (100) according to the present invention includes a fluid passage (S) formed by heat transferred during the process of sealing the outer material (120), so that gas generated by charging and discharging of the secondary battery (100) can be easily discharged to the outside. In this case, the stability of the secondary battery (100) is improved, and there is an advantageous effect of maintaining the performance of the secondary battery (100) for a longer period of time.

[0131] Secondary battery manufacturing method

[0132] Figure 13 is a flowchart of a secondary battery manufacturing method according to the present invention.

[0133] Referring to FIG. 13, a method for manufacturing a secondary battery according to the present invention may include a foam member arrangement step (S200) of arranging a foam member (150) having a foaming property due to heat on one side of an electrode lead (130); a film attachment step (S300) of attaching a lead film (140) made of an insulating material to at least a portion of the electrode lead (130); a connection step (S400) of electrically connecting an electrode assembly (110) disposed inside an outer material (120) and including a negative electrode, a positive electrode, and a separator to the electrode lead (130), and a sealing step (S500) of sealing the inside of the outer material (120) by bonding the outer material (120) and the lead film (140). In the film attachment step (S300), the lead film (140) is attached only to a part of the electrode lead (130), so that a fluid path (S) through which gas generated during charging and discharging of the electrode assembly (110) moves can be formed between the lead film (140) and the electrode lead (130).

[0134] The secondary battery (100) manufactured by the secondary battery manufacturing method described above has a fluid path (S) through which the internal gas of the outer casing (120) moves between the electrode lead (130) and the lead film (140), and a thermally expandable foam member (150) may be provided in the fluid path (S). In this case, the foam member (150) foams by receiving heat generated during charging and discharging of the electrode assembly between the electrode lead (130) and the lead film (140), thereby expanding the fluid path (S) through which the gas inside the outer casing (120) moves. Accordingly, the internal gas of the outer casing (120) moves through the expanded fluid path (S) and is discharged to the outside of the outer casing (120), thereby delaying or preventing rupture of the outer casing (120) due to an increase in internal pressure.

[0135] The foam member arrangement step (S200) is a step of arranging a foam member (150) having heat-induced foaming properties on one side of the electrode lead (130), and may be a step of arranging the foam member (150) on the upper surface of the electrode lead (130). The foam member (150) arranged on the upper surface of the electrode lead (130) may be adhered to the upper surface of the electrode lead (130) by the film attachment step (S300).

[0136] The film attachment step (S300) is a step of attaching a lead film (140) made of an insulating material to the electrode lead (130). The lead film (140) may be attached to cover at least a portion of the electrode lead (130). The lead film (140) prevents the electrode lead (130) from directly contacting the outer material (120) and may be an insulating tape having an adhesive surface. At this time, the adhesive surface of the lead film (140) may be attached to the electrode lead (130).

[0137] The connecting step (S400) is a step of electrically connecting the electrode assembly (110) and the electrode lead (130), and the electrode assembly (110) and the electrode lead (130) can be connected in various ways. For example, the electrode assembly (110) includes a plurality of positive tabs and negative tabs, and the positive tabs and negative tabs can be connected to form a positive tab bundle and a negative tab bundle, respectively. The electrode lead (130) can be welded to the positive tab bundle and the negative tab bundle.

[0138] In this connection step (S400), the electrode lead (130) equipped with a foam member (150) and a lead film (140) can be connected to the positive tab or negative tab of the electrode assembly (110).

[0139] The sealing step (S500) is a step of sealing the inside of the outer material (120), and may be a step of applying heat and pressure to the outer material (120) and the lead film (140) to combine the outer material (120) and the lead film (140). In this case, the open area of ​​the outer material (120) where the electrode lead (130) protrudes is sealed by the lead film (140), so that the inner space (A) of the outer material (120) can be sealed.

[0140] Meanwhile, during this sealing step (S500), the heat applied to the lead film (140) and the outer material (120) may also be transferred to the foam member (150). In this case, at least a portion of the foam member (150) may undergo thermal expansion and / or foaming.

[0141] Specifically, the foam member (150) provided between the electrode lead (130) and the lead film (140) receives heat and foams, and the pressure formed by the foaming causes the fluid passage (S) to expand. Through the expanded fluid passage (S), the internal gas of the outer material (120) can smoothly move.

[0142] Specifically, one end of the fluid passage (S) is in contact with the internal space (A) of the outer material (120), so that the internal gas of the outer material (120) can flow into one end of the fluid passage (S). The other end of the fluid passage (S) is not exposed to the external space of the outer material (120), but the lead film (140) is formed as a semi-permeable film that is impermeable to the electrolyte but permeable to the gas, so that the gas flowing into the fluid passage (S) can be discharged to the outside through the lead film (140).

[0143] Meanwhile, the foam member (150) can foam at various temperatures to form a fluid movement path (S). For example, the foam member (150) can thermally expand and foam at a temperature of 150°C or higher.

[0144] In the foam member arrangement step (S200), the foam member (150) can be attached to one side of the electrode lead (130). The attachment of the foam member (150) and the electrode lead (130) can be performed in various ways. For example, the foam member arrangement step (S300) can be a step of forming an adhesive layer on one side of the electrode lead (130) and then placing the foam member (150) on the adhesive layer.

[0145] Additionally, in the foam member arrangement step (S200), the foam member (150) may be coated on one side of the electrode lead (130). The coating of the foam member (150) may be performed in various ways. For example, the foam member (150) may be coated on the electrode lead (130) using a thermosetting material such as resin. In this case, the cured resin may form a coating layer.

[0146] In the film attachment step (S300), a lead film (140) is attached to one side of the electrode lead (130) provided with the foam member (150), so that the foam member (150) can be in close contact with the electrode lead (130). Specifically, the adhesive surface of the lead film (140), which is an insulating tape, is attached to the foam member (150) and the electrode lead (130), and the foam member (150) can be pressed against the electrode lead (130) by the lead film (140). In this case, the foam member (150) is in close contact with the electrode lead (130), and the position of the foam member (150) can be fixed on one side of the electrode lead (130).

[0147] In addition, in the film attachment step (S300), the lead film (140) may be attached to the electrode lead (130) so that one end thereof is arranged parallel to one end of the foam member (150). Specifically, in the film attachment step (S300), the foam member (150) may be arranged parallel to one end of the lead film (140). At this time, although not shown in FIGS. 9 to 12, the foam member (150) may have the same shape as the sheet-shaped foam member (13`) illustrated in FIG. 7.

[0148] Here, one end of the lead film (140) may be one end that is in contact with the internal space (A) of the outer material (120). In this way, when the foam member (150) is placed on one end of the lead film (140), the fluid passage (S) formed by foaming of the foam member (150) may be connected to the internal space (A) of the outer material (120). In this case, the gas currently trapped in the internal space (A) of the outer material (120) can easily flow into the fluid passage (S), thereby efficiently discharging the internal gas of the outer material (120).

[0149] Meanwhile, the secondary battery manufacturing method according to the present invention is performed prior to the foam member arrangement step (S200) described above, and may further include a pad arrangement step (S100) of arranging a pad-shaped member on one surface of an electrode lead (130).

[0150] Specifically, the secondary battery manufacturing method according to the present invention may include a pad arrangement step (S100) of arranging a pad-shaped member on one side of an electrode lead (130), a foam member arrangement step (S200) of arranging a foam member (150) on the pad-shaped member, a film attachment step (S300) of attaching a lead film (140) to the electrode lead (130) and the pad-shaped member, a connection step (S400) of connecting the electrode assembly (110) and the electrode lead (130), and a sealing step (S500) of sealing the internal space (A) of the outer material (120).

[0151] The pad arrangement step (S100) is a step of arranging a pad-shaped member on the upper surface of the electrode lead (130), and the arrangement of the pad-shaped member can be configured in various ways. For example, in the pad arrangement step (S110), the pad-shaped member can be adhered to the upper surface of the electrode lead (130). At this time, the pad-shaped member can have various shapes. For example, when the pad-shaped member is viewed from above, the pad-shaped member can have an approximate "T" or "ㅠ" shape.

[0152] At this time, at least a portion of the upper surface of the pad-shaped member may not be bonded to the lead film (140). In this case, the space between the portion of the upper surface of the pad-shaped member that is not bonded to the lead film (140) and the lead film (140) may be used as a fluid passage (S) through which the internal gas of the outer material (120) may move. This fluid passage (S) may be configured in various shapes. For example, the fluid passage (S) may have an approximate "T" or "ㅠ" shape when viewed from above.

[0153] Meanwhile, in the foam member arrangement step (S200), the foam member (150) may be arranged on one side of the pad-shaped member. Specifically, the foam member (150) may be arranged on a portion corresponding to the fluid movement path (S) among the upper surfaces of the pad-shaped member provided on the upper side of the electrode lead (130). This foam member (150) may receive heat in the sealing step (S500) to expand and foam, thereby expanding the fluid movement path (S).

[0154] Meanwhile, in the film attachment step (S300), the foam member (150) can be adhered to the pad-shaped member by the lead film (140). Specifically, the foam member (150) is placed on the upper surface of the pad-shaped member, and the foam member (150) can be adhered to the upper surface of the pad-shaped member by the lead film (140), which is an insulating tape. The lead film (140), which is an insulating tape, can be attached to the pad-shaped member and the electrode lead (130) while the foam member (150) is pressed. In this case, the foam member (150) is adhered to the pad-shaped member, and the position of the foam member (150) can be fixed on the upper surface of the pad-shaped member.

[0155] In addition, in the connection step (S400), the electrode lead (130) provided with a pad-shaped member, a foam member (150), and a lead film (140) can be connected to the positive electrode tab or the negative electrode tab of the electrode assembly (110). Specifically, a portion of the electrode lead (130) where the pad-shaped member, the foam member (150), and the lead film (140) are not disposed can be welded to the positive electrode tab or the negative electrode tab of the electrode assembly (110).

[0156] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0157] [Explanation of symbols]

[0158] 10: Electrode lead assembly 11: Electrode lead

[0159] 12: Lead film 13: Foam member

[0160] 13a: Shell 13b: Effervescent material

[0161] 14: Coating layer 15: Pad-shaped member

[0162] S: Fluid path S1: First fluid path

[0163] S2: Second fluid path

Claims

1. Electrode leads; A lead film composed of an insulating material and adhered to a portion of the electrode lead; and It includes a foam member having foaming properties due to heat, An electrode lead assembly in which a fluid path is formed between the electrode lead and the lead film, and the foam member is provided in the fluid path.

2. In claim 1, The above fluid movement path is, A first fluid path extending along the length of the electrode lead from one end of the lead film; and An electrode lead assembly comprising a second fluid path connected to the first fluid path and extending along the width direction of the electrode lead.

3. In claim 2, The above foam member is an electrode lead assembly provided in the first fluid movement path.

4. In claim 1, The above foam member is an electrode lead assembly that is foamed at a temperature of 150°C or higher.

5. In claim 1, The above foam member has a sheet shape and is an electrode lead assembly attached to one side of the electrode lead.

6. In claim 1, The above foam member, A shell composed of a polymer material that expands when heated; and An electrode lead assembly, which is enclosed in the above shell and includes a foaming material that foams when heated.

7. In claim 1, An electrode lead assembly further comprising a coating layer for coating the foam member on the electrode lead.

8. In claim 1, An electrode lead assembly further comprising a pad-shaped member having one side bonded to the electrode lead.

9. In claim 8, An electrode lead assembly formed between the above fluid movement path and the pad-shaped member and the lead film.

10. A foam member arrangement step of arranging a foam member having heat-induced foaming properties on one side of the electrode lead; and A film attachment step for attaching a lead film made of an insulating material to the electrode lead on which the foam member is arranged, A method for manufacturing an electrode lead assembly, wherein in the film attachment step, the lead film is attached only to a portion of the electrode lead, and a fluid path through which a fluid moves is formed between the lead film and the electrode lead.

11. In claim 10, A method for manufacturing an electrode lead assembly, wherein in the film attachment step, the foam member is adhered to the electrode lead by the lead film.

12. In claim 10, A method for manufacturing an electrode lead assembly, wherein in the film attachment step, the lead film is attached to the electrode lead so that one end thereof is arranged parallel to one end of the foam member.

13. In claim 10, A method for manufacturing an electrode lead assembly, wherein in the above foam member arrangement step, the foam member is attached to one surface of the electrode lead.

14. In claim 10, A method for manufacturing an electrode lead assembly, wherein in the above foam member arrangement step, the foam member is coated on one surface of the electrode lead.

15. In claim 10, A method for manufacturing an electrode lead assembly, the method further comprising a pad arrangement step of arranging a pad-shaped member on one surface of the electrode lead, the method being performed prior to the foam member arrangement step.

16. In claim 15, A method for manufacturing an electrode lead assembly, wherein in the above foam member arrangement step, the foam member is arranged on one side of the pad-shaped member.

17. In claim 16, A method for manufacturing an electrode lead assembly, wherein in the film attachment step, the foam member is adhered to the pad-shaped member by the lead film.

18. Electrode assembly including a cathode, an anode, and a separator; An outer material accommodating the above electrode assembly; An electrode lead electrically connected to the electrode assembly and protruding outward from the outer surface of the outer material; and A lead film is included that is adhered to a portion of the electrode lead so that the electrode lead is insulated from the outer material, A fluid path is formed between the electrode lead and the lead film through which gas generated during charging and discharging of the electrode assembly moves. A secondary battery in which a foaming member having foaming properties due to heat is provided in the above fluid movement path.

19. In claim 18, A secondary battery in which the foam member is placed adjacent to the internal space of the outer material that accommodates the electrode assembly among the fluid passages.

20. In claim 19, The above fluid movement path is, A first fluid passage adjacent to the internal space of the outer material and extending along the length of the electrode lead; and A secondary battery comprising a second fluid path connected to the first fluid path and extending along the width direction of the electrode lead.

21. In claim 20, The above foam member is a secondary battery provided in the first fluid movement path.

22. A foam member arrangement step of arranging a foam member having heat-induced foaming properties on one side of the electrode lead; A film attachment step of attaching a lead film made of an insulating material to the electrode lead on which the foam member is arranged; A connecting step for electrically connecting an electrode assembly including a cathode, an anode, and a separator and the electrode lead, which is placed inside the outer material; and A sealing step for sealing the inside of the outer material by bonding the outer material and the lead film is included. A secondary battery manufacturing method in which, in the film attachment step, the lead film is attached only to a portion of the electrode lead, so that a fluid path through which gas generated during charging and discharging of the electrode assembly moves is formed between the lead film and the electrode lead.

23. In claim 22, A method for manufacturing a secondary battery, wherein the sealing step includes a step of applying heat and pressure to the outer material and the lead film, and at least a portion of the foam member is foamed by the heat applied in the sealing step.

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