Pouch film laminate, pouch-type battery case, and pouch-type secondary battery

Abstract

The present invention relates to a pouch film laminate comprising a sealant layer, a barrier layer, and a base layer, the pouch film laminate further comprising a high-melting point resin layer on at least one surface of the barrier layer, wherein the high-melting point resin layer comprises a solid-state polymer electrolyte (SPE), and the high-melting point resin layer has a melting point higher than those of the sealant layer and the base layer.

Description

Pouch film laminate, pouch-type battery case and pouch-type secondary battery Cross-citation with related applications This application claims the benefit of priority to Korean Patent Application No. 10-2024-0018478, filed February 6, 2024, and Korean Patent Application No. 10-2025-0014108, filed February 4, 2025, the entire contents of which are incorporated herein by reference. Technology field The present invention relates to a pouch film laminate, a pouch-type battery case, and a pouch-type secondary battery. Secondary batteries are generally manufactured by applying electrode active material slurry to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode, laminating them on both sides of a separator to form an electrode assembly of a predetermined shape, and then storing the electrode assembly in a pouch and injecting an electrolyte. Secondary batteries are classified into pouch type and can type depending on the material of the case that accommodates the electrode assembly. Among these, pouch type secondary batteries are manufactured by performing press processing on a flexible pouch film laminate to form a cup portion, housing the electrode assembly in the cup portion, injecting an electrolyte, and then sealing the seal portion. Can type secondary batteries are manufactured by housing the electrode assembly in a can made of a metal material, injecting an electrolyte, and then assembling a top cam on the top of the can to seal it. Pouch-type secondary batteries have the advantages of being light, having excellent space utilization, and being able to achieve high energy density by using a stacked electrode assembly, but they have the problem of being vulnerable to external impact compared to can-type secondary batteries. Recently, as the usage environments of secondary batteries have diversified, there is a growing demand for excellent durability and safety even in harsh environments. Accordingly, not only mechanical safety from foreign substances such as nail penetration but also safety from thermal propagation in the event of an actual fire is required. The present invention is intended to solve the above problems, and relates to a pouch film laminate, a pouch-type battery case, and a pouch-type secondary battery having excellent safety, heat resistance, and heat-blocking effect at high temperatures. The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned can be clearly understood by those skilled in the art from the description below. [1] The present invention provides a pouch film laminate comprising a sealant layer; a barrier layer; and a substrate layer, wherein the pouch film laminate further comprises a high-melting point resin layer on at least one surface of the barrier layer, the high-melting point resin layer comprises a solid-state polymer electrolyte (SPE), and the high-melting point resin layer has a melting point higher than the melting point of the sealant layer. [2] The present invention can provide a pouch film laminate in the above [1], wherein the high-melting-point resin layer has an elongation higher than the elongation of the base layer. [3] The present invention can provide a pouch film laminate according to [1] or [2], wherein the solid polymer electrolyte (SPE) includes a lithium salt and a polymer matrix, and the polymer matrix includes at least one selected from the group consisting of polycarbonate, polyester, polynitrile, polyalcohol, polyamine, polysiloxane, ethylene carbonate, and fluoropolymer. [4] The present invention can provide a pouch film laminate in the above [3], wherein the solid polymer electrolyte (SPE) can further include at least one of succinonitrile (SN) and ethyl cyanoacetate (CN). [5] The present invention can provide a pouch film laminate in which, in at least one of the above [1] to [4], the high-melting-point resin layer is positioned between the sealant layer and the barrier layer and between the barrier layer and the substrate layer. [6] The present invention can provide a pouch film laminate in which the high-melting-point resin layer further includes a thermosetting polymer material in at least one of the above [1] to [5]. [7] The present invention can provide a pouch film laminate in the above [6], wherein the thermosetting polymer material includes at least one selected from the group consisting of polyimide-based resin, polyester-based resin, epoxy-based resin, amino-based resin, phenol-based resin, melamine-based resin, and rubber-based resin. [8] The present invention can provide a pouch film laminate in which the melting point of the high-melting-point resin layer is 160°C or higher in at least one of the above [1] to [7]. [9] The present invention can provide a pouch film laminate having an elongation of the high-melting-point resin layer of 300% or more in at least one of the above [1] to [8].

[0010] The present invention can provide a pouch film laminate in which the thickness of the high-melting-point resin layer is 5 µm to 200 µm in at least one of the above [1] to [9].

[0011] The present invention can provide a pouch-shaped battery case including at least one cup portion curved in one direction by forming a pouch film laminate according to at least one of the above [1] to

[0010] .

[0012] The present invention can provide a pouch-type secondary battery including a pouch-type battery case according to the above

[0011] . According to the present invention, a pouch film laminate comprises a sealant layer, a barrier layer, and a substrate layer sequentially laminated, and a high-melting-point resin layer comprising a solid polymer electrolyte (SPE) positioned on at least one surface of the barrier layer. When the high-melting-point resin layer comprises a solid polymer electrolyte (SPE) material, it has a higher melting point than the sealant layer and higher mechanical strength, such as elongation, than the substrate layer, so that it can maintain its shape as much as possible and physically maintain electrical insulation even when subjected to external impact or abnormal heating. Therefore, it is possible to improve not only mechanical safety against foreign substances such as nail penetration, but also safety against thermal propagation in the event of an actual fire. Figures 1 to 3 are cross-sectional views of a pouch film laminate according to one embodiment of the present invention. Figure 4 is an exploded perspective view of a secondary battery according to one embodiment of the present invention. 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 spirit 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 possible manner. It should be understood that the terms “include,” “comprising,” or “having” used in this specification are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof. In this specification, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in that phrase, or all possible combinations thereof. In this specification, MD direction (Machine Direction) means the longitudinal direction of the pouch film laminate, and TD direction (Transverse Direction) means the width direction of the pouch film laminate. The drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the contents of the invention described above, serve to further enhance the understanding of the technical spirit of the present invention. Therefore, the present invention is not limited to the matters described in these drawings. Meanwhile, the shape, size, scale, or ratio of elements in the drawings included in this specification may be exaggerated to emphasize a clearer explanation. Hereinafter, the present invention will be described in detail. The pouch film laminate according to the present invention comprises at least one of the configurations disclosed below, and may comprise any combination between technically possible configurations among the configurations below. With the technological development and increasing demand for electric vehicles and energy storage systems (ESS), the demand for batteries as an energy source is rapidly increasing. Consequently, research is being conducted to develop batteries that can meet diverse needs. In particular, active research is being conducted on lithium secondary batteries, which possess high energy density and excellent lifespan and cycling characteristics as power sources for these devices. However, lithium secondary batteries can experience rapid increases in electrode temperature due to thermal and physical factors. Thermal factors include overcharging or overloading caused by misuse or malfunctions such as chargers. Physical factors include damage to the separator due to external impact, causing contact between the negative and positive electrode materials, resulting in a rapid increase in electrode temperature. If the electrode temperature rises rapidly in this way, the electrolyte and lithium may react, or hydrogen and oxygen may be generated within the battery, making the battery extremely unstable. In addition, the electrolyte solvent may decompose, generating gas, which may ignite and lead to an explosion of the battery. Recently, as the usage environments of secondary batteries have diversified, there is a growing demand for excellent durability and safety even in harsh environments. Accordingly, not only mechanical safety from foreign substances such as nail penetration but also safety from thermal propagation in the event of an actual fire is required. The inventors of the present invention have conducted repeated research to achieve excellent safety by thermal propagation in the event of an actual fire, and as a result, they have discovered that a pouch film laminate can maintain its shape as much as possible and maintain physical electrical insulation even in the event of a physical impact from the outside or abnormal heat generation by further including a high-melting-point resin layer including at least one of a solid polymer electrolyte (SPE) material and a thermosetting polymer material having a high melting point and high mechanical strength, thereby completing the present invention. Pouch film laminate A pouch film laminate according to the present invention is a pouch film laminate comprising a sealant layer; a barrier layer; and a substrate layer, and further comprising a high-melting point resin layer on at least one surface of the barrier layer, wherein the high-melting point resin layer comprises a solid-state polymer electrolyte (SPE), and the high-melting point resin layer is characterized in that it has a melting point higher than the melting point of the sealant layer. 1 to 3 are cross-sectional views of a pouch film laminate according to an embodiment of the present invention. In one embodiment, the pouch film laminate according to the present invention may sequentially laminate a sealant layer (30), a high-melting-point resin layer (40), a barrier layer (20), and a substrate layer (10). In one embodiment, the pouch film laminate according to the present invention may sequentially laminate a sealant layer (30), a barrier layer (20), a high-melting-point resin layer (40), and a substrate layer (10). In one embodiment, the pouch film laminate according to the present invention may sequentially laminate a sealant layer (30), a high-melting-point resin layer (40), a barrier layer (20), a high-melting-point resin layer (40), and a substrate layer (10). Hereinafter, each layer of the pouch film laminate according to the present invention will be described in detail. (High melting point resin layer) The high-melting point resin layer (40) is arranged on at least one surface of the barrier layer (20), and specifically, may be located between the sealant layer (30) and the barrier layer (20) or between the barrier layer (20) and the substrate layer (10). More specifically, the high-melting point resin layer (40) may be located between the sealant layer (30) and the barrier layer (20) and between the barrier layer (20) and the substrate layer (10). The high-melting point resin layer (40) above can increase the melting point of the entire pouch film laminate by including a solid-state polymer electrolyte (SPE), and can also achieve excellent mechanical strength such as elongation, thereby maintaining the shape as much as possible and physically maintaining electrical insulation even in the event of a physical impact from the outside or abnormal heat generation. Therefore, not only mechanical safety from foreign substances such as nail penetration but also safety from thermal propagation in the event of an actual fire can be improved. Specifically, since the solid polymer electrolyte (SPE) generally has a higher melting point than the material constituting the sealant layer, the high-melting-point resin layer including the solid polymer electrolyte melts later than the sealant layer, or, in particular, does not melt when including a thermosetting polymer material, thereby maintaining its shape at high temperatures, thereby improving thermal safety. In addition, the high-melting-point resin layer including the solid polymer electrolyte (SPE) has higher mechanical strength, such as elongation, than the base layer, and thus can absorb shocks when subjected to external impacts and maintain its shape, thereby improving mechanical safety. Specifically, the solid polymer electrolyte has a higher melting point than a thermosetting polymer material, and thus can implement a high-melting-point resin layer with excellent mechanical strength. For example, the melting point of the solid polymer electrolyte is 180°C or higher, which is higher than the melting point of polypropylene, which is mainly used in pouches, which is 160°C to 170°C. The above solid polymer electrolyte (SPE) is a material in which lithium salt is dissociated within a polymer matrix to conduct lithium ions. The lithium salt may be, for example, LiClO4, LiBrF4, LiPF6, LiNSO3CF3, or LiN(SO2CF3)2. The polymer matrix may include at least one selected from the group consisting of polycarbonate, polyester, polynitrile, polyalcohol, polyamine, polysiloxane, and fluoropolymer. The polymer matrix may be, for example, polyacrylonitrile (PAN), polytrimethylenecarbonate (PTMC), polycaprolactone (PCL), polyvinylidene fluoride (PVdF), poly(vinylidene fluoride)-hexafluoropropyl copolymer (PVDF-HFP), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), polyoxypropylene glycol (PPG), polyethylene oxide (PEO), polymethyl methacrylate (PMMA), polyethylene carbonate (PEC), polypropylene carbonate (PPC), polydimethylsiloxane (PVDF-HFP), The solid polymer electrolyte (SPE) may include at least one selected from the group consisting of polydimethylsiloxane (PDMS) and polyvinyl pyrrolidine (PVP). Preferably, the solid polymer electrolyte (SPE) may include polypropylene carbonate. The above solid polymer electrolyte (SPE) may further include a nitrile group-containing compound. For example, the nitrile group-containing compound may include at least one selected from the group consisting of succinonitrile (SN) and ethyl cyanoacetate (CN). When the solid polymer electrolyte (SPE) further includes succinonitrile (SN) and / or ethyl cyanoacetate (CN), the thermal stability of the solid polymer electrolyte (SPE) at high temperatures can be improved. For example, the solid polymer electrolyte (SPE) may be a combination of PEO, PVdF, LiClO4 and SN, a combination of PAN, PVA-CN and SN, a combination of PAN and SN, or a combination of PVA-CN and acrylonitrile. The high-melting-point resin layer (40) may further include a thermosetting polymer material. The thermosetting polymer material refers to a polymer material that, when heated to a high temperature, forms a cross-linked structure within the polymer chain and hardens, exhibiting a hardening phenomenon, and having a melting point higher than its decomposition temperature. The thermosetting polymer material may include, for example, at least one selected from the group consisting of polyimide-based resins, polyester-based resins, epoxy-based resins, amino-based resins, phenol-based resins, melamine-based resins, and rubber-based resins. Preferably, the thermosetting polymer material may include at least one selected from the group consisting of polyimide-based resins, epoxy-based resins, and melamine-based resins. Preferably, the thermosetting polymer material may include a polyimide-based resin. The above high-melting point resin layer (40) contains both a solid polymer electrolyte (SPE) and a thermosetting polymer material, thereby achieving the effect of improving both the thermal safety and mechanical durability of the pouch film laminate. The above high-melting-point resin layer (40) is characterized by having a higher melting point than the melting points of the sealant layer (30) and the substrate layer (10). The melting point of the high-melting-point resin layer (40) may be 160°C or higher, specifically 200°C or higher, and more specifically 240°C or higher, and further, the melting point of the high-melting-point resin layer (40) may be 210°C or lower, specifically 200°C or lower, and more specifically 195°C or lower. When the melting point of the high-melting-point resin layer (40) satisfies the above range, a high-melting-point resin layer having excellent processability and excellent heat stability can be implemented. The above high-melting-point resin layer (40) may have a value greater than the elongation of the base layer (10). The elongation of the high-melting-point resin layer (40) may be 300% or more, specifically 400% or more, and more specifically 500% or more. When the elongation of the high-melting-point resin layer (40) satisfies the above range, a high-melting-point resin layer having excellent processability and mechanical durability can be realized. When the melting point and elongation of the high-melting point resin layer (40) satisfy the above range, there is an effect of physically maintaining electrical insulation while maintaining the shape as much as possible even when subjected to a physical impact or abnormal heat generation from the outside. The thickness of the high-melting-point resin layer (40) may be 5 µm to 200 µm, preferably 8 µm to 150 µm, and more preferably 10 µm to 120 µm. If the thickness of the high-melting-point resin layer (40) is too thin, the effect of alleviating external impacts may be minimal, and it may be weak against heat transmission at high temperatures. If the thickness is too thick, the thickness of the case may increase, which may cause a problem of reduced energy density (ED) due to an increase in battery volume and weight. (base layer) The above-mentioned substrate layer (10) is arranged on the outermost layer of the pouch-type battery case (100) to protect the electrode assembly from external impact and electrically insulate it. The above-mentioned substrate layer (10) may be made of a polymer material, and for example, may be made of one or more polymer 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, and Teflon. The above substrate layer (10) may have a single-layer structure or may have a multi-layer structure in which different polymer films are laminated. If the substrate layer (10) has a multi-layer structure, an adhesive layer may be interposed between the polymer films. Meanwhile, the substrate layer (10) may have a total thickness of 10 μm to 60 μm, preferably 15 μm to 50 μm, and more preferably 20 μm to 40 μm. When the substrate layer (10) has a multilayer structure, the thickness includes the adhesive layer. When the substrate layer (10) satisfies the above range, durability, insulation, and formability are excellent. If the thickness of the substrate layer (10) is too thin, durability is reduced, and the substrate layer may be damaged during the forming process, and if it is too thick, formability may be reduced, the overall thickness of the pouch may increase, and the battery accommodation space may be reduced, which may lower the energy density. According to one embodiment, the substrate layer (10) may be a laminated structure of a polyethylene terephthalate (PET) film and a nylon film. In this case, it is preferable that the nylon film is placed on the barrier layer (20) side, i.e., on the inside, and the polyethylene terephthalate film is placed on the surface side of the pouch. Polyethylene terephthalate (PET) has excellent durability and electrical insulation properties, and when a PET film is placed on the surface side, it exhibits excellent durability and insulation properties. However, in the case of the PET film, the adhesion to the aluminum alloy thin film constituting the barrier layer (20) is weak, and the stretching behavior is also different. Therefore, when the PET film is placed on the barrier layer (20) side, the substrate layer and the barrier layer (20) may be peeled off during the forming process, and the barrier layer (20) may not be stretched uniformly, which may cause a problem of reduced formability. In contrast, since the stretching behavior of a nylon film is similar to that of an aluminum alloy thin film constituting the barrier layer (20), when a nylon film is placed between the polyethylene terephthalate and the barrier layer (20), an effect of improved formability can be obtained. The above polyethylene terephthalate film may have a thickness of 5 µm to 20 µm, preferably 5 µm to 15 µm, and more preferably 7 µm to 15 µm, and the above nylon film may have a thickness of 10 µm to 40 µm, preferably 10 µm to 35 µm, and more preferably 15 µm to 25 µm. When the thicknesses of the polyethylene terephthalate film and the nylon film satisfy the above ranges, excellent formability and post-formed rigidity are exhibited. (barrier layer) The barrier layer (20) is intended to secure the mechanical strength of the pouch-type battery case (100), block the ingress of gas or moisture from outside the secondary battery, and prevent leakage of electrolyte. The barrier layer (20) may have a thickness of 30 µm to 120 µm, more preferably 40 µm to 100 µm, and even more preferably 40 µm to 80 µm. When the thickness of the barrier layer (20) satisfies the above range, the formability is improved, thereby increasing the cup portion forming depth, or reducing the occurrence of cracks and / or pinholes even when forming two cups, thereby improving resistance to external stress after forming. Meanwhile, the barrier layer (20) may be made of a metal material, and specifically, may be made of an aluminum alloy thin film. The above aluminum alloy thin film may include one or more kinds selected from the group consisting of aluminum and metal elements other than aluminum, for example, iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), silicon (Si), and zinc (Zn). (Sealant layer) The above sealant layer (30) is bonded through heat compression to seal the pouch, and is located on the innermost layer of the pouch film laminate. The sealant layer (30) must have insulating and corrosion resistance properties because it is the surface that comes into contact with the electrolyte and electrode assembly after the pouch is formed, and must completely seal the inside to block material movement between the inside and the outside, so it must have high sealing properties. The above sealant layer (30) may be made of a polymer material, and may be made of at least one selected from the group consisting of, for example, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, and Teflon. Among these, it is particularly preferable to include polypropylene (PP), which has excellent mechanical properties such as tensile strength, rigidity, surface hardness, wear resistance, and heat resistance, and chemical properties such as corrosion resistance. More specifically, the sealant layer (30) may include polypropylene, cast polypropylene (CPP), acid modified polypropylene, polypropylene-butylene-ethylene copolymer, or a combination thereof. The above sealant layer (30) may have a single-layer structure or may have a multi-layer structure including two or more layers made of different polymer materials. The sealant layer (30) may have a total thickness of 60 µm to 100 µm, preferably 60 µm to 90 µm, and more preferably 70 µm to 90 µm. If the thickness of the sealant layer (30) is too thin, the sealing durability and insulation may be reduced, and if it is too thick, the flexibility may be reduced and the total thickness of the pouch film laminate may increase, which may lower the energy density per volume. The pouch film laminate according to the present invention can be manufactured through a manufacturing method of a pouch film laminate known in the art. For example, the pouch film laminate according to the present invention can be manufactured through a method of attaching a high-melting-point resin layer (40) to one surface of a barrier layer (20) using an adhesive, attaching a substrate layer (10) to one surface of the high-melting-point resin layer (40) using an adhesive, and then forming a sealant layer (30) on the other surface of the barrier layer (20) using coextrusion or an adhesive, but is not limited thereto. pouch-type battery case Fig. 4 is an exploded perspective view of a pouch-type secondary battery according to the present invention. Hereinafter, with reference to Fig. 4, a secondary battery according to one embodiment of the present invention will be described in more detail. The above pouch-type battery case (100) is a battery case for accommodating an electrode assembly (200) and an electrolyte (not shown), and includes a substrate layer, a barrier layer, a high-melting-point resin layer, and a sealant layer, which are the pouch film laminates, and includes at least one cup portion (accommodating portion, 110) recessed in one direction. Since the detailed configuration and properties of the pouch film laminate are the same as those described above, a detailed description thereof will be omitted. Specifically, the pouch-shaped battery case (100) has flexibility and can be manufactured by inserting a pouch film laminate in which a substrate layer, a barrier layer, a high-melting-point resin layer, and a sealant layer are sequentially laminated into a press molding device, and applying pressure with a punch to a portion of the pouch film laminate to stretch it, thereby forming a cup portion having a shape that is concave in one direction. The pouch-shaped battery case (100) of the present invention manufactured through the above method includes a lower case (101), an upper case (102), and a folding part (130) connecting the lower case and the upper case, and the upper case and / or the lower case includes a cup part (110) having a shape that is recessed in one direction. Specifically, the pouch-type battery case (100) according to the present invention may be a single-cup type in which the cup portion (110) is formed only in the lower case (101), as illustrated in FIG. 4, but is not limited thereto, and may be a double-cup type in which cup portions are formed in both the upper case and the lower case. In the case of a double-cup type pouch, since the upper case is folded so that the cup portions of the upper case and the cup portions of the lower case face each other after accommodating the electrode assembly and the electrolyte, it is possible to accommodate an electrode assembly having a thicker thickness than a single-cup type pouch, and thus has the advantage of being advantageous in implementing high energy density. The cup portion (110) has a receiving space for receiving the electrode assembly (200). Meanwhile, the pouch-type battery case (100) may include a terrace (120) around the cup portion (110). The terrace (120) refers to a non-molded portion of the pouch film laminate, i.e., the remaining area excluding the cup portion (110). The terrace (120) is a portion that is sealed through thermal bonding in a process of receiving the electrode assembly (200) in the cup portion (110), injecting an electrolyte, and then sealing. The cup portion (110) may include a bottom surface and a peripheral surface. The peripheral surface may connect the bottom surface and the terrace (120). A plurality of peripheral surfaces, more specifically four, may be provided. The bottom surface may cover one side of the electrode assembly (200), and the peripheral surface may surround the perimeter of the electrode assembly (200). Meanwhile, the folding portion (130) connects the lower case (101) and the upper case (102), accommodates the electrode assembly (200) in the cup portion (110), and, after injecting the electrolyte, folds to allow the upper case (102) to seal the cup portion (110) of the lower case (101). When the folding portion (130) is included, the lower case (101) and the upper case (102) are connected as one piece, so that when performing the sealing process later, the number of sides to be sealed is reduced, thereby improving the processability. The above folding portion (130) is formed to be spaced apart from the cup portion (110), and the distance between the folding portion (130) and the cup portion (110) may be 0.5 mm to 3 mm, preferably 0.5 mm to 2 mm. If the folding portion (130) is formed too close to the cup portion (110), folding may not be performed smoothly, and if the folding portion (130) is formed too far from the cup portion (110), the overall volume of the secondary battery may increase, thereby decreasing the energy density per volume. In the case of a two-cup case, the folding portion may be formed to satisfy the above distance for each cup portion. pouch-type secondary battery Next, a pouch-type secondary battery according to the present invention will be described. A pouch-type secondary battery according to the present invention may include a pouch-type battery case (100) manufactured by molding the aforementioned pouch film laminate, and an electrode assembly (200) housed in the pouch-type battery case (100). Since the detailed configuration and physical properties of the pouch-type battery case (100) are the same as those described above, a detailed description thereof will be omitted. Specifically, a pouch-type secondary battery according to the present invention may include a pouch-type battery case (100), an electrode assembly (200), an electrode tab (230), a lead (240), an insulator (250), and an electrolyte (not shown). (electrode assembly) The electrode assembly (200) can be inserted into a pouch-type battery case (100) and sealed by the pouch-type battery case (100) after electrolyte injection. The electrode assembly (200) may include a plurality of electrodes and a plurality of separators that are alternately stacked. The plurality of electrodes may be alternately stacked with the separator in between and include positive and negative electrodes having opposite polarities. Additionally, the electrode assembly (200) may be provided with a plurality of electrode tabs (230) welded to each other. The plurality of electrode tabs (230) may be connected to a plurality of electrodes and may protrude outwardly from the electrode assembly (200) to act as a passage through which electrons may move between the inside and the outside of the electrode assembly (200). The plurality of electrode tabs (230) may be located inside the pouch-type battery case (100). The electrode tab (230) connected to the positive electrode and the electrode tab (230) connected to the negative electrode may protrude in different directions with respect to the electrode assembly (200). However, this is not limited to the present invention, and the electrode tab (230) connected to the positive electrode and the electrode tab (230) connected to the negative electrode may also protrude in the same direction while being parallel to each other. A lead (240) for supplying electricity to the outside of the secondary battery can be connected to a plurality of electrode tabs (230) by spot welding or the like. One end of the lead (240) is connected to the plurality of electrode tabs (230) and the other end can protrude to the outside of the pouch-type battery case (100). A portion of the lead (240) may be surrounded by an insulating portion (250). For example, the insulating portion (250) may include an insulating tape. The insulating portion (250) may be positioned between the terrace (120) of the lower case (101) and the upper case (102), and in this state, the terrace (120) and the upper case (102) may be thermally fused to each other. In this case, a portion of the terrace (120) and the upper case (102) may be thermally fused to the insulating portion (250). Accordingly, the insulating portion (250) may prevent electricity generated from the electrode assembly (200) from flowing to the pouch-type battery case (100) through the lead (240) and maintain the sealing of the pouch-type battery case (100). (electrolyte) The electrolyte is used to move lithium ions generated by the electrochemical reaction of the electrodes during charging and discharging of the secondary battery, and may include an organic solvent and a lithium salt. As the organic solvent, any solvent that can act as a medium through which ions involved in the electrochemical reaction of the battery can move may be used without particular limitation. Specifically, the organic solvent includes ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; carbonate solvents such as dimethylcarbonate (DMC), diethylcarbonate (DEC), ethylmethylcarbonate (EMC), ethylenecarbonate (EC), and propylene carbonate (PC); Alcohol solvents such as ethyl alcohol, isopropyl alcohol, etc.; nitriles such as R-CN (wherein R is a C2 to C20 linear, branched, or cyclic hydrocarbon group, which may include a double-bonded aromatic ring or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes can be used. Among these, carbonate solvents are preferable, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate) having high ionic conductivity and high dielectric constant that can improve the charge / discharge performance of a battery and a low-viscosity linear carbonate compound (e.g., ethyl methyl carbonate, dimethyl carbonate, or diethyl carbonate) is more preferable. The above lithium salt can be used without any special restrictions as long as it is a compound capable of providing lithium ions used in a lithium secondary battery. Specifically, the anion of the lithium salt may be at least one selected from the group consisting of F-, Cl-, Br-, I-, NO3-, N(CN)2-, BF4-, CF3CF2SO3-, (CF3SO2)2N-, (FSO2)2N-, CF3CF2(CF3)2CO-, (CF3SO2)2CH-, (SF5)3C-, (CF3SO2)3C-, CF3(CF2)7SO3-, CF3CO2-, CH3CO2-, SCN-, and (CF3CF2SO2)2N-, and the lithium salt may be LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, or LiB(C2O4)2 can be used. The concentration of the lithium salt is preferably within the range of 0.1M to 4.0M, preferably 0.5M to 3.0M, and more preferably 1.0M to 2.0M. When the concentration of the lithium salt is within the above range, the electrolyte can exhibit excellent electrolyte performance because it has appropriate conductivity and viscosity, and lithium ions can move effectively. In addition to the electrolyte components, the electrolyte may further include one or more additives, such as haloalkylene carbonate compounds such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, cyclic ethers, ethylene diamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, or aluminum trichloride, for the purpose of improving the life characteristics of the battery, suppressing battery capacity decrease, and improving the discharge capacity of the battery. At this time, the additives may be included in an amount of 0.1 to 10.0 wt% based on the total weight of the electrolyte. Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. Example 1 A pouch film laminate having a structure in which polyethylene terephthalate (thickness: 12 μm) / nylon (thickness: 25 μm) / Al alloy thin film (thickness: 60 μm) / high-melting-point resin layer (polypropylene carbonate (PCC), lithium lanthanum tantalum zirconate (LLZTO), anhydrous acetonitrile (anhydrous acetonitrile), thickness: 40 μm) / non-stretched polypropylene (thickness: 40 μm) are sequentially laminated was manufactured. Example 2 A pouch film laminate having a structure in which polyethylene terephthalate (thickness: 12 μm) / nylon (thickness: 25 μm) / high-melting point resin layer / high-melting point resin layer (polypropylene carbonate (PCC), lithium lanthanum tantalum zirconate (LLZTO), anhydrous acetonitrile, thickness: 40 μm) / Al alloy thin film (thickness: 60 μm) / non-stretched polypropylene (thickness: 40 μm) are sequentially laminated was manufactured. Example 3 A pouch film laminate having a structure in which polyethylene terephthalate (thickness: 12 μm) / nylon (thickness: 25 μm) / high-melting point resin layer (polypropylene carbonate (PCC), lithium lanthanum tantalum zirconate (LLZTO), anhydrous acetonitrile, thickness: 40 μm) / Al alloy thin film (thickness: 60 μm) / high-melting point resin layer (polyimide, thickness: 20 μm) / non-stretched polypropylene (thickness: 20 μm) are sequentially laminated was manufactured. Comparative Example 1 A pouch film laminate having a structure in which polyethylene terephthalate (thickness: 12 μm) / nylon (thickness: 25 μm) / Al alloy thin film (thickness: 60 μm) / non-stretched polypropylene (thickness: 80 μm) are sequentially laminated was manufactured. Comparative Example 2 A pouch film laminate having a structure in which polyethylene terephthalate (thickness: 12 ㎛) / nylon (thickness: 25 ㎛) / Al alloy thin film (thickness: 60 ㎛) / high-melting point resin layer (polyimide, thickness: 40 ㎛) / non-stretched polypropylene (thickness: 40 ㎛) are sequentially laminated was manufactured. Comparative Example 3 A pouch film laminate having a structure in which polyethylene terephthalate (thickness: 12 ㎛) / nylon (thickness: 25 ㎛) / high-melting-point resin layer (polyimide, thickness: 40 ㎛) / Al alloy thin film (thickness: 60 ㎛) / non-stretched polypropylene (thickness: 40 ㎛) are sequentially laminated was manufactured. Experimental Example 1 A pouch-type battery case with a cup portion formed using the pouch film laminates manufactured in Examples 1 to 3 and Comparative Examples 1 to 3 was prepared. A stacked electrode assembly having a total length of 330 mm, a total width of 115 mm, and a weight of 700 g was placed in the above cup, an electrolyte was injected, then sealed, and an activation process was performed to manufacture a pouch-type secondary battery. For the pouch-type secondary battery manufactured as described above, experiments were conducted on 1) fire risk prevention due to thermal runaway, 2) time delay effect on thermal propagation, and 3) mechanical safety due to foreign substances such as nail penetration. The results of the experiments are shown in [Table 1] below. In this case, in [Table 1], the "◎" mark means very good, the "○" mark means good, the "△" mark means average, and the "X" mark means poor. Specifically, the experimental methods for 1) preventing fire hazards due to thermal runaway, 2) time delay effects on thermal propagation, and 3) mechanical safety during nail penetration are as follows. 1) Five of the manufactured battery cells are made into one module, and a heating pad is attached to one of the battery cells to apply heat at a rate of 0.5°C / sec. The battery cell to which the heating pad is attached is observed for ignition. At this time, the longer the delay in the time from the initial occurrence of ignition (fire or smoke), the better it is judged to be. 2) Five of the above-mentioned manufactured battery cells are made into one module, and a heating pad is attached to one of the battery cells to apply heat at a rate of 0.5°C / sec. At this time, the heat transferred to the adjacent cell is measured using a thermocouple, and it is judged that the longer the time it takes for the heat to propagate, the better. 3) A nail with a diameter of 3 mm was used to penetrate the center of the manufactured battery cell at a speed of 0.1 mm / s, and ignition was observed. At this time, the longer the time until ignition (fire or smoke) first occurred, the better. 1) Fire risk prevention due to thermal runaway 2) Time delay effect on thermal propagation 3) Safety from nail penetration Example 1○○○ Example 2○○○ Example 3◎◎○Comparative Example 1XXXComparative Example 2○○△Comparative Example 3○○△ From the above [Table 1], it can be confirmed that the pouch-type secondary battery including the pouch film laminate manufactured by Examples 1 to 3 has good 1) fire risk prevention due to thermal runaway, 2) time delay effect for thermal propagation, and 3) mechanical safety during nail penetration. On the other hand, it can be confirmed that the pouch-type secondary battery of Comparative Example 1, which does not include a high-melting-point resin layer, is significantly inferior to the pouch-type secondary batteries of Examples 1 to 3 in 1) prevention of fire risk due to thermal runaway, 2) time delay effect for thermal propagation, and 3) mechanical safety upon nail penetration. In addition, it can be confirmed that the pouch-type secondary batteries of Comparative Examples 2 and 3, which do not include a solid polymer electrolyte, have inferior mechanical safety compared to the pouch-type secondary batteries of Examples 1 to 3. [Explanation of symbols] 10: Substrate layer 20: Barrier layer 30: Sealant layer 40: High-melting point resin layer 100: Pouch-type battery case 101: Lower Case 102: Upper case 110: Cup 120: Terrace 130: Folding section 200: Electrode assembly 230: Electrode tab 240: Lead 250: Insulation

Claims

1. A pouch film laminate comprising a sealant layer; a barrier layer; and a substrate layer, Further comprising a high-melting point resin layer on at least one surface of the above barrier layer, The above high-melting point resin layer includes a solid-state polymer electrolyte (SPE), A pouch film laminate wherein the high-melting point resin layer has a melting point higher than the melting point of the sealant layer.

2. In claim 1, A pouch film laminate in which the high-melting-point resin layer has an elongation higher than that of the base layer.

3. In claim 1, The above solid polymer electrolyte (SPE) comprises a lithium salt and a polymer matrix, A pouch film laminate wherein the polymer matrix comprises at least one selected from the group consisting of polycarbonate, polyester, polynitrile, polyalcohol, polyamine, polysiloxane, and fluoropolymer.

4. In claim 3, A pouch film laminate wherein the above solid polymer electrolyte (SPE) further comprises at least one of succinonitrile (SN) and ethyl cyanoacetate (CN).

5. In claim 1, A pouch film laminate in which the high-melting point resin layer is positioned between the sealant layer and the barrier layer and between the barrier layer and the substrate layer.

6. In claim 1, A pouch film laminate wherein the high-melting point resin layer further comprises a thermosetting polymer material.

7. In claim 6, A pouch film laminate in which the thermosetting polymer material comprises at least one selected from the group consisting of polyimide resin, polyester resin, epoxy resin, amino resin, phenol resin, melamine resin, and rubber resin.

8. In claim 1, A pouch film laminate having a melting point of the high-melting point resin layer of 160°C or higher.

9. In claim 1, A pouch film laminate having an elongation of the high-melting-point resin layer of 300% or more.

10. In claim 1, A pouch film laminate having a thickness of the high-melting point resin layer of 5 µm to 200 µm.

11. A pouch-shaped battery case comprising at least one cup portion curved in one direction by forming a pouch film laminate according to any one of claims 1 to 10.

12. A pouch-type secondary battery comprising a pouch-type battery case according to claim 11.

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