Secondary battery and method of manufacturing same

Abstract

The secondary battery according to an embodiment of the present invention may comprise: an electrode assembly; a first exterior material which surrounds the electrode assembly to seal the electrode assembly; a second exterior material, at least a portion of which is spaced apart from the first exterior material, the second exterior material surrounding the outer surface of the first exterior material; and an electrode lead electrically connected to the electrode assembly and extending from the inside of the first and second exterior materials to the outside.

Description

Secondary battery and method for manufacturing the same

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2024-0029900, filed February 29, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a secondary battery capable of being charged and discharged and a method for manufacturing the same.

[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 secondary batteries, power is charged when a reduction reaction occurs in the material due to current, and discharge occurs when an oxidation reaction occurs in the material. This repeated charging and discharging process generates electricity.

[0008] The object of the present invention is to provide a secondary battery having improved quality and performance by preventing sealing defects and insulation defects, and a method for manufacturing a secondary battery having improved efficiency in the manufacturing process.

[0009] A secondary battery according to one embodiment of the present invention may include an electrode assembly, a first outer covering material that surrounds the electrode assembly so as to seal the electrode assembly, a second outer covering material that is at least partially non-bonded to the first outer covering material and surrounds an outer surface of the first outer covering material, and an electrode lead that is electrically connected to the electrode assembly and extends from the inside to the outside of the first outer covering material and the second outer covering material.

[0010] The above first exterior material may have heat sealing properties and gas permeability.

[0011] The electrode assembly may further include an electrolyte accommodated inside the first outer shell.

[0012] The second exterior material may include a sealant layer having heat sealing properties and provided facing the first exterior material.

[0013] The above sealant layer can be at least partially bonded to the first exterior material by sealing.

[0014] The second outer casing material may be joined by sealing the sealant layers facing each other so that the first outer casing material is sealed.

[0015] The second outer material may include a metal layer including a metal material and an insulating layer including an insulating material.

[0016] The second outer material may include a metal layer including stainless steel (SUS), and the outer surface of the metal layer may be coated with nylon.

[0017] At least one hole may be formed in a portion of the second outer material.

[0018] A method for manufacturing a secondary battery according to an embodiment of the present invention may include (a) a step of sealing a first outer case containing an electrode assembly in a cup portion, (b) a step of activating the electrode assembly provided inside the sealed first outer case by charging and discharging, (c) a step of discharging gas trapped in a gas collection portion of the first outer case through activation, (d) a step of removing the gas collection portion of the first outer case, and (e) a step of wrapping the first outer case with a second outer case.

[0019] The method for manufacturing a secondary battery may further include, after step (c), a step of sealing between the cup portion and the gas collection portion.

[0020] The method for manufacturing a secondary battery may further include, before step (e), a step of forming at least one hole in a portion of the second outer shell.

[0021] In the above step (e), the first outer material and the second outer material can be joined to each other by heat sealing.

[0022] A battery pack according to another aspect of the present invention may include a secondary battery according to one aspect of the present invention.

[0023] A vehicle according to another aspect of the present invention may include a battery pack according to one aspect of the present invention.

[0024] A secondary battery according to an embodiment of the present invention may include a first outer shell and a second outer shell.

[0025] Accordingly, the performance decline of the secondary battery due to poor sealing can be prevented.

[0026] Additionally, wrinkles in the second outer material can be prevented from occurring due to gases generated during the activation process.

[0027] As a result, problems such as poor insulation in secondary batteries can be reduced.

[0028] A secondary battery according to an embodiment of the present invention may have a hole formed in the second outer material.

[0029] Accordingly, the gas generated inside the secondary battery can be efficiently discharged to the outside.

[0030] Through this, the deterioration of the secondary battery's function can be prevented.

[0031] In addition, the safety of the secondary battery can be improved by delaying or preventing the venting phenomenon of the pouch caused by the gas inside the outer material.

[0032] In a method for manufacturing a secondary battery according to an embodiment of the present invention, a second outer material may be bonded after the activation process and the degassing process are completed.

[0033] Accordingly, the cost consumed for removing the gas capture unit can be reduced, thereby improving the economic efficiency of the process.

[0034] In addition, the degree of freedom for hole formation increases, and the bonding of the second outer material becomes easier, so the efficiency of the process can be improved.

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

[0036] The following drawings attached to this specification illustrate embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0037] FIG. 1 is a perspective view schematically illustrating a secondary battery according to Example 1 of the present invention.

[0038] Figure 2 is a partially cut-away perspective view of a secondary battery according to Example 1 of the present invention.

[0039] Figure 3 is a cross-sectional view schematically illustrating a cross-section taken along line A-A' of Figure 1.

[0040] Figure 4 is a perspective view schematically illustrating a secondary battery according to Example 2 of the present invention.

[0041] Figure 5 is a flowchart schematically illustrating a method for manufacturing a secondary battery according to Example 3 of the present invention.

[0042] FIG. 6 is a plan view schematically illustrating a state in which a first outer material surrounds an electrode assembly in a method for manufacturing a secondary battery according to Example 3 of the present invention.

[0043] Figure 7 is a plan view schematically illustrating a state in which a gas collection unit is removed in a method for manufacturing a secondary battery according to Example 3 of the present invention.

[0044] FIG. 8 is a plan view schematically illustrating a state in which a second outer material surrounds a first outer material in a method for manufacturing a secondary battery according to Example 3 of the present invention.

[0045] FIG. 9 is a perspective view illustrating a vehicle including a battery pack according to an embodiment of the present invention.

[0046] In some of the accompanying drawings, corresponding components are designated by the same reference numerals. Those skilled in the art will appreciate that the drawings illustrate elements simply and clearly and are not necessarily drawn to scale. For example, to facilitate understanding of various embodiments, the dimensions of some elements depicted in the drawings may be exaggerated relative to other elements. Furthermore, elements of known technology that are useful or essential in commercially feasible embodiments may often not be depicted so as not to obscure the spirit of various embodiments of the present invention.

[0047] Hereinafter, 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 embodiments.

[0048] 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.

[0049] In addition, terms or 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.

[0050] Secondary batteries can be classified into cylindrical cells, pouch cells, and prismatic cells depending on their shape. Among them, a pouch cell 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.

[0051] The pouch cell manufacturing process may include a process of discharging gas trapped within the gas collection portion of the pouch, and a process of removing the gas collection portion after the gas is discharged. Furthermore, the pouch cell manufacturing process may include a process of resealing the pouch from which the gas collection portion has been removed. During this process, electrolyte may be deposited on the portion cut to remove the gas collection portion. Electrolyte deposited on the cut portion may result in poor sealability when the pouch is resealed.

[0052] The present invention provides a secondary battery having improved quality and performance by preventing the problem of reduced sealing properties, and a method for manufacturing a secondary battery having improved efficiency in the manufacturing process.

[0053] Example 1

[0054] Fig. 1 is a perspective view schematically illustrating a secondary battery (10) according to Embodiment 1 of the present invention. Fig. 2 is a partial cutaway perspective view of a secondary battery (10) according to Embodiment 1 of the present invention, and Fig. 3 is a cross-sectional view schematically illustrating a cross-section taken along line A-A' of Fig. 1.

[0055] The secondary battery (10) according to Example 1 of the present invention may refer to a secondary battery capable of being charged and discharged. For example, the secondary battery (10) may have a shape in which an electrode assembly (100) is housed inside a case in the form of an outer case.

[0056] The electrode assembly (100) 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 (100) 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.

[0057] Conventional secondary batteries having an electrode assembly arranged within a pouch have a high possibility of sealing failures occurring during the manufacturing process, which can reduce the performance of the secondary battery. Conventional pouch-type secondary batteries may include a process of removing a space where gases generated during the activation process are trapped and resealing the pouch. In the conventional pouch-type secondary battery manufacturing process, a sealing failure may occur due to electrolyte contamination in the portion that seals the pouch, and the sealing failure may lead to insulation failure. The insulation failure may cause a decrease in the performance of the completed secondary battery.

[0058] As an example of a configuration for preventing or suppressing problems such as poor insulation, the secondary battery (10) according to Example 1 of the present invention may include a first outer material (200) and a second outer material (300) for sealing the electrode assembly (100).

[0059] Referring to FIGS. 1 and 2, the secondary battery (10) according to Embodiment 1 of the present invention may have a form in which a first outer shell (200) and a second outer shell (300) accommodate an electrode assembly (100). The first outer shell (200) may surround the electrode assembly (100) so that the electrode assembly (100) is sealed. In addition, the second outer shell (300) may surround the outer surface of the first outer shell (200).

[0060] For example, the first outer casing (200) may primarily seal the electrode assembly (100), and the second outer casing (300) may secondarily seal the electrode assembly (100). Unlike a conventional pouch having multiple layers, the secondary battery (10) according to Embodiment 1 of the present invention may have separate configurations of the first outer casing (200) and the second outer casing (300). Accordingly, the first outer casing (200) and the second outer casing (300) may be arranged so that at least a portion thereof is spaced apart from each other. For example, in the first outer casing (200) and the second outer casing (300), portions that are not sealed for sealing the electrode assembly (100) may not be joined to each other. That is, at least a portion of the first outer casing (200) and the second outer casing (300) may be non-bonded.

[0061] An electrolyte may be accommodated inside the first outer casing (200) that primarily seals the electrode assembly (100). For example, the electrolyte may be an electrolyte. Since the first outer casing (200) is sealed with the electrode assembly (100) and the electrolyte accommodated therein, the second outer casing (300) can prevent a decrease in sealing performance due to the electrolyte. Accordingly, the secondary battery (10) according to the first embodiment of the present invention can prevent a decrease in performance due to a sealing defect. As a result, the occurrence of problems such as insulation defects in the secondary battery (10) can be reduced. In addition, the sealing performance of the secondary battery (10) with respect to the electrode assembly (100) and the electrolyte can be improved due to the double sealing by the first outer casing (200) and the second outer casing (300).

[0062] Meanwhile, the secondary battery (10) may include an electrode lead (400). The electrode lead (400) may be electrically connected to the electrode assembly (100). The electrode lead (400) may be provided to extend from the inside to the outside of the first outer case (200) and the second outer case (300). The secondary battery (10) may provide electric energy to the outside by the electrode lead (400) protruding to the outside of the first outer case (200) and the second outer case (300). Therefore, the electrode lead (400) may be a conductor.

[0063] The secondary battery (10) may further include a lead film (500). The lead film (500) may cover the electrode lead (400) so that the first outer material (200) and the electrode lead (400) are insulated from each other. For example, the lead film (500) may be placed on both sides of the electrode lead (400) to cover the electrode lead (400). The lead films (500) may be configured as a pair and may be placed on each side of the electrode lead (400).

[0064] The lead film (500) may include a material having heat-sealing properties. Accordingly, the lead film (500) and the first outer material (200) may be bonded through sealing.

[0065] The first outer shell (200) of the secondary battery (10) according to Example 1 of the present invention may have heat-sealing properties. For example, the first outer shell (200) may be formed of a material having heat-sealing properties. Accordingly, the first outer shell (200) may be sealed so that the electrode assembly (100) is accommodated therein through sealing. In addition, the first outer shell (200) may be coupled to the lead film (500) through sealing.

[0066] In order to have heat sealing properties, the first exterior material (200) may be made of one or more materials selected from polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, Teflon, and glass fiber. For example, the first exterior material (200) may use a polyolefin resin such as polypropylene (PP) or polyethylene (PE).

[0067] The second outer shell (300) of the secondary battery (10) according to Example 1 of the present invention may include a plurality of layers. For example, the second outer shell (300) may include a sealant layer (310) having heat-sealing properties.

[0068] Referring to FIG. 3, the sealant layer (310) of the second exterior material (300) may be provided to face the first exterior material (200). For example, the sealant layer (310) may be placed at the innermost side among the multiple layers included in the second exterior material (300).

[0069] Since the first exterior material (200) and the second exterior material (300) are separate exterior materials, not all parts may be adhered to each other. Therefore, portions of the first exterior material (200) and the second exterior material (300) may be arranged to have a gap between them. For example, the sealant layers (310) of the first exterior material (200) and the second exterior material (300) may be arranged to have a gap between them, or may not be adhered to each other. FIG. 3 is an enlarged drawing showing a portion where the first exterior material (200) and the sealant layer (310) are arranged to have a gap between them.

[0070] Meanwhile, a portion of the first outer material (200) may be bonded to the sealant layer (310) of the second outer material (300) through sealing. For example, a portion of the first outer material (200) that is sealed for sealing the electrode assembly (100) may be bonded to the sealant layer (310) of the second outer material (300) through sealing. The first outer material (200) and the sealant layer (310) may be sealed through heat and pressure.

[0071] In order to have heat sealing properties, the sealant layer (310) of the second exterior material (300) may be made of one or more materials selected from polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, Teflon, and glass fiber. For example, the sealant layer (310) may use a polyolefin resin such as polypropylene (PP) or polyethylene (PE).

[0072] Referring to FIG. 3, the second outer shell (300) of the secondary battery (10) according to Example 1 of the present invention may include a metal layer (320) and an insulating layer (330).

[0073] The metal layer (320) of the second outer shell (300) may include a metal material. For example, the metal layer (320) may include aluminum (Al). Since the second outer shell (300) includes the metal layer (320), the structural rigidity of the secondary battery (10) may be improved.

[0074] The insulating layer (330) of the second outer shell (300) may include an insulating material. Referring to FIG. 3, the insulating layer (330) may be positioned at the outermost side among the multiple layers included in the second outer shell (300). For example, the insulating layer (330) may include a nylon-based resin. The insulating layer (330) may insulate the metal layer (320) from the outside.

[0075] Meanwhile, as the secondary battery (10) is repeatedly charged and discharged, gas may be generated, which may increase the pressure inside the first outer case (200). If the pressure inside the first outer case (200) increases excessively, a venting phenomenon may occur, causing the secondary battery (10) to lose its function.

[0076] For example, an electrolyte may be accommodated together with an electrode assembly (100) inside the first outer casing (200) of the secondary battery (10). At this time, residual moisture of the electrolyte inside the first outer casing (200) of the secondary battery (10) 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. In addition, depending on the material of the positive electrode included in the electrode assembly (100) of the secondary battery (10), hydrogen and HF may be additionally generated, which may cause 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 first outer casing (200). The pressure inside the first outer material (200) increases due to such gas, and the swelling phenomenon in which the first outer material (200) swells due to the increased pressure or the venting phenomenon in which a part of the first outer material (200) bursts may occur.

[0077] The secondary battery (10) according to Example 1 of the present invention may include a structure capable of discharging internal gas to the outside to prevent the venting phenomenon from occurring. For example, the first outer shell (200) may have gas permeability. For example, the first outer shell (200) may be made of a material having gas permeability. Accordingly, gas generated within the first outer shell (200) may permeate the first outer shell (200) and be discharged to the outside of the first outer shell (200).

[0078] The secondary battery (10) may include a first outer shell (200) and a second outer shell (300). Therefore, if the gas that has permeated the first outer shell (200) is not discharged to the outside of the second outer shell (300), the second outer shell (300) may swell or burst.

[0079] As an example of a configuration for emitting gas, the second outer shell (300) of the secondary battery (10) according to Example 1 of the present invention may have a hole (340) formed therein. For example, at least one hole (340) may be formed in a portion of the second outer shell (300).

[0080] As described above, the gas inside the first outer casing (200) can permeate the first outer casing (200) having gas permeability. On the other hand, the gas that has permeated the first outer casing (200) having gas permeability cannot permeate the second outer casing (300) including the metal layer (320). At this time, the gas that has permeated the first outer casing (200) can be discharged to the outside of the secondary battery (10) through the hole (340) of the second outer casing (300).

[0081] The holes (340) formed in the second outer shell (300) may vary in shape, size, and number. For example, the holes (340) may be formed in a portion corresponding to the portion that accommodates the electrode assembly (100) of the first outer shell (200). Additionally, the holes (340) may be formed in multiples.

[0082] The secondary battery (10) may have a form in which the first outer casing (200) seals the electrode assembly (100) and then the second outer casing (300) surrounds the first outer casing (300). At this time, since only the edge of the second outer casing (300) is bonded to the first outer casing (200), a space (gap) may be formed between the first outer casing (200) and the second outer casing (300) in the non-bonded portion. Gas that has permeated the first outer casing (200) may move along the space (gap) between the first outer casing (200) and the second outer casing (300) and be discharged to the outside through the hole (340) formed in the second outer casing (300). Therefore, the positions at which the hole (340) may be formed in the second outer casing (300) may be more diverse.

[0083] In addition, during the process of manufacturing the secondary battery (10), the second outer material (300) may wrap the sealed first outer material (200) with the electrode assembly (100) housed therein. At this time, a hole (340) may be formed in the second outer material (300) before wrapping the first outer material (200). Accordingly, the degree of freedom in terms of the position, number, shape, etc. of the holes (340) formed in the second outer material (300) may be increased.

[0084] In the secondary battery (10) according to the first embodiment of the present invention, since a hole (340) is formed in the second outer casing (300), gas generated inside the secondary battery (10) can be efficiently discharged to the outside. Through this, the problem of deterioration of the secondary battery (10) can be prevented or suppressed. In addition, in the secondary battery (10) according to the first embodiment of the present invention, since the first outer casing (200) and the second outer casing (300) are installed as described above, the venting phenomenon caused by the gas inside can be delayed or prevented, so that safety can be improved.

[0085] Example 2

[0086] Figure 4 is a perspective view schematically illustrating a secondary battery (10) according to Example 2 of the present invention.

[0087] Hereinafter, a detailed description of the same configuration as that of the secondary battery (10) according to Example 1 of the present invention will be omitted, and the differences will be mainly explained.

[0088] The secondary battery (10) according to Example 2 of the present invention may have a different shape of the second outer shell (300) from the secondary battery (10) according to Example 1 of the present invention.

[0089] The second outer shell (300) of the secondary battery (10) according to Example 2 of the present invention may include a plurality of layers. For example, the second outer shell (300) may include a sealant layer (310) and a metal layer (320).

[0090] The sealant layer (310) of the second exterior material (300) may have heat-sealing properties. For example, the sealant layer (310) may include a material having heat-sealing properties.

[0091] The metal layer (320) of the second exterior material (300) may include a metal material. For example, the metal layer (320) of the second exterior material (300) may include stainless steel (SUS). In addition, the metal layer (320) may have an outer surface coated with an insulating material. For example, the metal layer (320) may have an outer surface coated with nylon. Here, the outer surface of the metal layer (320) may mean the opposite surface of the surface facing the sealant layer (310).

[0092] Referring to FIG. 4, in the secondary battery (10) according to Embodiment 2 of the present invention, the opposing sealant layers (310) of the second outer casing (300) can be bonded to each other so that the second outer casing (300) seals the first outer casing (200). For example, the opposing sealant layers (310) of the second outer casing (300) can be bonded by sealing so that the first outer casing (200) is sealed. For example, the first outer casing (200) can seal the electrode assembly (100) accommodated therein, and the second outer casing (300) can seal the first outer casing (200) accommodated therein.

[0093] For example, the second outer shell (300) may cover the first outer shell (200) that accommodates the electrode assembly (100) on both sides. At this time, the edge of the second outer shell (300) may be sealed by heat sealing. Here, the second outer shell (300) may be sealed by a sealant layer (310) disposed on the edge.

[0094] In the secondary battery (10) according to Example 2 of the present invention, the second outer casing (300) is not bonded to the first outer casing (200), and the facing second outer casings (300) can be bonded to each other. Accordingly, the first outer casing (200) can be accommodated inside the second outer casing (300) without being visible from the outside (see FIG. 4).

[0095] Since the first outer material (200) is sealed in a state where it is contained within the second outer material (300), even if a crack occurs in the first outer material (200), the electrolyte, etc., does not flow out of the second outer material (300). Accordingly, the stability of the secondary battery (10) can be improved.

[0096] Referring to FIG. 4, a hole (340) having a different shape from that of Example 1 may be formed in the second outer shell (300) of the secondary battery (10) according to Example 2 of the present invention. However, this is merely an example, and the shape, position, number, etc. of the hole (340) may vary.

[0097] In addition to the shape of the second outer material (300) according to various embodiments described in the present invention, the shape of the second outer material (300) may be varied for structural stability and efficient gas discharge.

[0098] Example 3

[0099] Fig. 5 is a flowchart schematically illustrating a method for manufacturing a secondary battery according to Embodiment 3 of the present invention. Fig. 6 is a plan view schematically illustrating a state in which a first outer material (200) surrounds an electrode assembly (100) in a method for manufacturing a secondary battery according to Embodiment 3 of the present invention, and Fig. 7 is a plan view schematically illustrating a state in which a gas collection unit (210) is removed in a method for manufacturing a secondary battery according to Embodiment 3 of the present invention.

[0100] Referring to FIGS. 5 and 6, a method for manufacturing a secondary battery (10) according to Embodiment 3 of the present invention may include a step (S1) of sealing a first outer case (200) containing an electrode assembly (100). Here, the first outer case (200) may refer to an outer case including a gas collection unit (210) and a cup unit (220). For example, the first outer case (200) described in Embodiment 3 of the present invention may be an outer case having a different form from the first outer case (200) described in the previous embodiment in that it includes a gas collection unit (210), but may also be an outer case having the same form as the first outer case (200) described in the previous embodiment, if necessary. The cup unit (220) may refer to a space in which the electrode assembly (100) is arranged, and the gas collection unit (210) may be provided to have a gap with the cup unit (220).

[0101] Referring to FIG. 6, the first outer shell (200) can be sealed with the electrode assembly (100) accommodated in the cup portion (220). For example, the electrode assembly (100) and the electrolyte can be accommodated in the cup portion (220).

[0102] Next, a step (S2) of activating the electrode assembly (100) provided inside the sealed first outer material may be performed by charging and discharging. Through this, electrical characteristics can be imparted to the electrode assembly (100). In the secondary battery manufacturing method according to the third embodiment of the present invention, the electrode assembly (100) may be activated while being sealed only with the first outer material (200). For example, in the secondary battery manufacturing method according to the third embodiment of the present invention, activation may be performed while the second outer material (300) is not applied after the electrode assembly (100) is sealed with the first outer material (200).

[0103] Meanwhile, during the process of activating the electrode assembly (100), for example, gas may be generated inside the first outer casing (200). The gas generated during the activation process may be captured in the gas collection unit (210) of the first outer casing (200). Therefore, a step (S3) of discharging the gas captured in the gas collection unit (210) of the first outer casing (200) through activation may be performed. For example, in the method for manufacturing a secondary battery according to Embodiment 3 of the present invention, after activation is performed in a state where only the first outer casing (200) surrounds the electrode assembly (100), the gas captured in the gas collection unit (210) may be removed or discharged.

[0104] There may be various methods for discharging the gas captured in the gas collection unit (210). For example, the gas may be discharged by forming one or more holes in the gas collection unit (210).

[0105] After the gas captured in the gas collection unit (210) is discharged, a step (S4) of sealing between the gas collection unit (210) and the cup unit (220) may be performed. For example, the area between the cut line (N) formed between the gas collection unit (210) and the cup unit (220) and the cup unit (220) may be sealed. As another example, the first outer material may be sealed along the cut line (N).

[0106] Thereafter, a step (S5) of removing the gas collection portion (210) of the first outer material (200) may be performed. For example, in the secondary battery manufacturing method according to Example 3 of the present invention, a portion of the first outer material (200) may be removed.

[0107] The first outer casing (200) may have heat sealing properties and gas permeability. For example, the first outer casing may be made of a polyolefin resin such as polypropylene (PP) or polyethylene (PE). While a pouch film composed of multiple layers must be removed during a conventional secondary battery manufacturing process, in the secondary battery manufacturing method according to Example 3 of the present invention, only a portion of the relatively inexpensive first outer casing (200) is removed, thereby reducing the cost incurred due to the removal of the gas collection unit (210). Accordingly, the economic feasibility of the secondary battery manufacturing process may be improved.

[0108] In the secondary battery manufacturing method according to Example 3 of the present invention, the first outer packaging material (200) may have an arbitrary cutting line (N) formed between the gas collection portion (210) and the cup portion (220) (see FIG. 6). The gas collection portion (210) may be removed by cutting this cutting line (N). The first outer packaging material from which the gas collection portion (210) has been removed may be left with only the cup portion (220) having the electrode assembly (100) arranged therein (see FIG. 7).

[0109] FIG. 8 is a plan view schematically illustrating a state in which a second outer material (300) wraps around a first outer material (200) in a method for manufacturing a secondary battery according to Example 3 of the present invention.

[0110] After the gas collection unit (210) is removed, a step (S7) of wrapping the first outer casing (200) with the second outer casing (300) may be performed. For example, by wrapping the first outer casing (200) with the second outer casing (300), the electrode assembly (100) may be sealed again, for example, in a double manner. For example, the second outer casing (300) may be bonded to the first outer casing (200) to seal the electrode assembly (100) again. Here, the first outer casing and the second outer casing (300) may be bonded to each other by heat sealing. In the secondary battery manufacturing method according to the third embodiment of the present invention, the first outer casing and the second outer casing (300) may be only partially bonded. Therefore, the first outer casing (200) and the second outer casing (300) may have at least some non-bonded portions.

[0111] In the secondary battery manufacturing method according to Example 3 of the present invention, activation and gas removal can be performed while the first outer covering (200) contains the electrode assembly (100) and the electrolyte. Therefore, the possibility of a sealing defect due to the electrolyte occurring during the sealing process of the second outer covering (300) can be reduced. Accordingly, the possibility of an insulation defect occurring due to a sealing defect can be reduced. In addition, since the second outer covering (300) can be easily sealed, the efficiency of the secondary battery manufacturing process can be improved.

[0112]

[0113] In order to efficiently discharge gas generated during the use of the completed secondary battery (10), the secondary battery manufacturing method according to Example 3 of the present invention may further include a step (S6) of forming at least one hole (340) in a portion of the second outer material (300).

[0114] For example, the step (S6) of forming a hole (340) in the second outer casing (300) may be performed before the step (S7) of wrapping the first outer casing (200) with the second outer casing (300). In the secondary battery manufacturing method according to Example 3 of the present invention, since the hole (340) is formed before the sealing of the second outer casing (300), the degree of freedom in forming the hole (340) may increase. Meanwhile, in another embodiment, the hole (340) in the second outer casing (300) may be performed after the step (S7) of wrapping the first outer casing (200) with the second outer casing (300).

[0115] Referring to FIG. 9, a plurality of secondary batteries (10) according to an embodiment of the present invention may be combined to form a battery module or battery pack (600). The battery pack (600) may be included in an automobile (700), such as an electric vehicle (EV) or a hybrid vehicle (HV). Here, the secondary battery (10) may be the secondary battery (10) described above. In addition, the battery pack (600) may drive the automobile (700) by supplying power to a motor through an inverter provided in the automobile (700). Here, the battery pack (600) may include a battery management device (not shown). For example, the automobile (700) may include a battery management device. In this case, the battery management device may be an on-board device included in the automobile (700).

[0116] 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.

Claims

1. Electrode assembly; A first outer covering material that surrounds the electrode assembly so that the electrode assembly is sealed; A second exterior material, at least a portion of which is non-bonded to the first exterior material and which surrounds the outer surface of the first exterior material; and A secondary battery comprising an electrode lead electrically connected to the electrode assembly and extending from the inside to the outside of the first outer shell and the second outer shell.

2. In claim 1, The above first exterior material is, A secondary battery having heat sealing properties and gas permeability.

3. In claim 1, A secondary battery further comprising an electrolyte accommodated inside the first outer shell together with the electrode assembly.

4. In claim 1, The above second exterior material is, A secondary battery having heat-sealing properties and including a sealant layer provided facing the first outer material.

5. In claim 4, The above sealant layer is, A secondary battery, at least a portion of which is joined to the first outer shell by a seal.

6. In claim 4, The above second exterior material is, A secondary battery in which the sealant layers facing each other are joined by sealing so that the first outer material is sealed.

7. In claim 1, The above second exterior material is, a metal layer comprising a metal material; and A secondary battery comprising an insulating layer including an insulating material.

8. In claim 1, The above second exterior material is, Contains a metal layer including stainless steel (SUS), A secondary battery in which the outer surface of the metal layer is coated with nylon.

9. In claim 1, A secondary battery, wherein at least one hole is formed in a portion of the second outer shell. 10.(a) A step of sealing the first outer material containing the electrode assembly in the cup portion; (b) a step of activating the electrode assembly provided inside the sealed first outer material by charging and discharging; (c) a step of discharging the gas captured in the gas capture portion of the first outer shell through activation; (d) a step of removing the gas collection portion of the first outer material; and (e) A method for manufacturing a secondary battery, comprising the step of wrapping the first outer material with a second outer material.

11. In claim 10, A method for manufacturing a secondary battery, further comprising, after the step (c), a step of sealing between the cup portion and the gas collection portion.

12. In claim 10, A method for manufacturing a secondary battery, further comprising, before the step (e), a step of forming at least one hole in a portion of the second outer shell.

13. In claim 10, In the above step (e), A method for manufacturing a secondary battery, wherein the first outer material and the second outer material are bonded to each other by heat sealing.

14. A battery pack comprising a secondary battery according to claim 1.

15. A vehicle comprising a battery pack according to claim 14.

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