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

Abstract

The present invention relates to a pouch film laminate in which a substrate layer, a gas barrier layer, and a sealant layer are sequentially laminated, wherein the sealant layer includes a first sealant layer including a polypropylene random copolymer and a second sealant layer including crosslinked polypropylene, and the degree of crosslinking of the second sealant layer is 52% to 80%.

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. 10-2023-0176099, filed December 6, 2023, and Korean Patent Application No. 10-2024-0156612, filed November 6, 2024, the entire contents of which are incorporated herein by reference. Technical field The present invention relates to a pouch film laminate, a pouch-shaped battery case, and a pouch-shaped secondary battery, and more particularly, to a pouch film laminate having excellent insulation properties while reducing the time required for sealing (tact time) of the pouch film laminate, and a pouch-shaped battery case and pouch-shaped secondary battery manufactured by molding the same. In general, types of secondary batteries include nickel cadmium batteries, nickel hydrogen batteries, lithium ion batteries, and lithium ion polymer batteries. These secondary batteries are used in not only small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, portable game devices, power tools, and e-bikes, but also large products requiring high output such as electric vehicles or hybrid vehicles, as well as power storage devices that store surplus generated power or renewable energy and backup power storage devices. To manufacture such a secondary battery, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode, and these are laminated on both sides of a separator to form an electrode assembly of a predetermined shape. Then, the electrode assembly is housed in a battery case, and an electrolyte is injected and then sealed. Secondary batteries are classified into pouch type and can type depending on the material of the case that accommodates the electrode assembly. The pouch type accommodates the electrode assembly in a pouch made of a flexible polymer material. The can type accommodates the electrode assembly in a case made of a material such as metal or plastic. The pouch, which is a case of a pouch-type secondary battery, is manufactured by performing press processing on a flexible pouch film laminate to form a cup portion. Once the cup portion is formed, an electrode assembly can be accommodated in the inner receiving space of the cup portion and the sealing portion can be sealed to manufacture a secondary battery. In general, a pouch film laminate is formed of multiple layers in which a polymer film, such as polyethylene terephthalate, is laminated on one surface of a metal material gas barrier layer, and a sealant layer is laminated on the other surface. Recently, as the capacity of pouch-type secondary batteries is being increased, the demand for pouches with excellent formability is increasing. In order to manufacture a pouch with excellent formability, if the thickness of the gas barrier layer is formed thickly, there is a problem that the sealant layer does not easily melt when sealing the pouch-type battery case. In the past, to solve this problem, a method of increasing the sealing temperature and / or sealing time was used as a method of applying more heat when sealing the pouch-type battery case. However, if the sealing time is increased to sufficiently melt the sealant layer during sealing to completely seal the pouch-type battery case, the time required to manufacture the secondary battery increases as a result, which causes a problem in that the productivity of the secondary battery decreases. In addition, although the sealing time can be reduced if the sealing temperature is increased, the appearance of the pouch may be deformed as the base layer melts. Meanwhile, if an excessive amount of heat is applied to the sealant layer during the pouch-type battery case sealing, there is a problem that the sealant layer is excessively deformed and the insulation resistance of the pouch film decreases. In this case, the insulation of the pouch-type battery case is reduced, so that the secondary battery cannot maintain a normal voltage, which may cause a low voltage, and there is a risk of explosion or fire due to an internal short circuit in the battery, and it may cause damage to the user's body. Therefore, there is a need to develop a pouch film laminate that can reduce the sealing time without increasing the sealing temperature during sealing of a pouch-type battery case and secure the insulation of the pouch-type battery case. The present invention is to solve the above problems, and to provide a pouch film laminate, a pouch-type battery case and a pouch-type secondary battery capable of preventing deformation of a sealing portion during the process of sealing a pouch-type battery case manufactured from a pouch film laminate, thereby improving both sealing quality and processability while shortening the sealing time, and sufficiently securing the insulation of the pouch-type battery case. [1] The present invention provides a pouch film laminate in which a substrate layer; a gas barrier layer; and a sealant layer are laminated in that order, wherein the sealant layer includes a first sealant layer including a polypropylene random copolymer and a second sealant layer including crosslinked polypropylene, and the crosslinked polypropylene has a crosslinking degree of 52% to 80%. [2] The present invention provides a pouch film laminate, wherein, in the above [1], the first sealant layer includes at least one selected from the group consisting of an ethylene-propylene random copolymer and a butene-propylene random copolymer. [3] The present invention provides a pouch film laminate, wherein, in the above [1] or [2], the ethylene monomer of the polypropylene random copolymer is contained in an amount of 5 to 50 wt% based on the total weight of the first sealant layer. [4] The present invention provides a pouch film laminate, wherein in at least one of the above [1] to [3], the second sealant layer comprises cross-linked homopolypropylene. [5] The present invention provides a pouch film laminate, wherein, in at least one of the above [1] to [4], a ratio (A / B) of the thickness (A) of the first sealant layer to the thickness (B) of the second sealant layer is 0.6 to 1.5. [6] The present invention provides a pouch film laminate, wherein the thickness of the sealant layer is 30 µm to 130 µm in at least one of the above [1] to [5]. [7] The present invention provides a pouch film laminate, wherein when sealed at 200° C. and 0.1 MPa for 3 seconds, the insulation resistance of the pouch film laminate is 1000 MΩ or more in at least one of the above [1] to [6]. [8] The present invention provides a pouch film laminate, wherein, in at least one of the above [1] to [7], the melting temperature of the sealant layer is 120°C to 150°C. [9] The present invention, in at least one of the above [1] to [8], the total thickness (D) of the two pouch film laminates before sealing A ) and two sheets of the above pouch film laminate were sealed at 200°C and 0.1 MPa for 3 seconds, and the total thickness (D) of the two sheets of the above pouch film laminate S ) of the ratio (D) S / D A ) provides a pouch film laminate having a thickness of 0.2 to 0.6.

[0010] The present invention provides a pouch film laminate, wherein, in at least one of the above [1] to [9], the sealant layer may further include a third sealant layer at the outermost portion, and the third sealant layer includes a polypropylene random copolymer.

[0011] The present invention provides a pouch film laminate, wherein, in at least one of the above [1] to

[0010] , the sealant layer is formed by sequentially laminating a first sealant layer, a second sealant layer, and a third sealant layer.

[0012] The present invention provides a pouch-shaped battery case manufactured by molding a pouch film laminate according to any one of [1] to

[0011] .

[0013] A pouch-shaped battery case manufactured by molding a pouch film laminate according to the above

[0012] ; and a pouch-shaped secondary battery including an electrode assembly housed in the pouch-shaped battery case are provided. According to the present invention, by configuring a sealant layer with a first sealant layer including a polypropylene random copolymer and a second sealant layer including a crosslinked polypropylene, and controlling the crosslinking degree of the second sealant layer to a specific range, melting of the substrate layer does not occur in the process of sealing a pouch-type battery case, thereby preventing deformation of the sealing portion, thereby improving appearance defects and shortening the sealing time. As a result, the sealing quality, processability, and productivity of a pouch-type battery case manufactured from the pouch film laminate of the present invention can be secured, and the durability and life characteristics of a pouch-type secondary battery can be improved. In addition, during the process of sealing the pouch-type battery case, even if excessive heat is applied to the sealant layer, the insulation resistance of the pouch-type battery case can be maintained above a certain level, so that the insulation of the pouch-type battery case can be sufficiently secured. Accordingly, the secondary battery can be driven at a normal voltage, so that the battery performance is not deteriorated, and a short circuit inside the battery can be prevented, thereby improving stability. Figure 1 is a cross-sectional view showing the structure of a pouch film laminate according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the structure of a pouch film laminate according to another embodiment of the present invention. Figure 3 is an exploded assembly diagram of a pouch-type secondary battery according to the present invention. Hereinafter, the present invention will be described in more detail. The 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 having meanings and concepts consistent with the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term in order to explain his or her own invention in the best manner. The terminology used in this specification is for the purpose of describing exemplary embodiments only and is not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms “include,” “comprising,” or “having” 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, “crosslinking degree” means the ratio of chemical bonds formed between polypropylene chains. The “crosslinking degree” of crosslinked polypropylene can be measured by the crosslinking degree measuring method of ASTM D2765, and specifically, the crosslinking degree of the crosslinked polyolefin resin can be obtained by grinding a certain amount of sample to prepare a powder form, putting it into a Timble Filter, and then using xylene contained in a reactor connected to a cooler, circulating the sample at 110°C for 12 hours to dissolve all uncrosslinked components, and then measuring the weight of the crosslinked but undissolved sample relative to the weight of the initially introduced sample, and then calculating it using the following formula. [Formula 1] Crosslinking degree (%) = (Weight of sample not dissolved in solvent / Weight of sample initially added) × 100 The pouch film laminate, pouch-shaped battery case, and lithium secondary battery according to the present invention include at least one of the following disclosed configurations, and may include any combination between technically possible configurations among the following configurations. The inventors of the present invention have conducted repeated studies to develop a pouch-type film laminate capable of preventing deformation of a sealing portion during sealing, shortening the sealing time, and securing the insulation resistance of a pouch-type battery case to a certain level or higher, and as a result, they have found that when a sealant layer is composed of a first sealant layer including a polypropylene random copolymer and a second sealant layer including crosslinked polypropylene, and the crosslinking degree of the second sealant layer is 52% to 80%, the sealing time of a pouch-type battery case manufactured using the pouch film laminate can be shortened without increasing the sealing temperature during sealing, thereby simultaneously improving the sealing quality, productivity, and processability, and the pouch-type battery case has sufficient insulation so that battery performance and stability can also be improved, thereby completing the present invention. Hereinafter, the present invention will be described in more detail. Pouch film laminate A pouch film laminate according to the present invention is a pouch film laminate in which a substrate layer; a gas barrier layer; and a sealant layer are laminated in that order, wherein the sealant layer includes a first sealant layer including a polypropylene random copolymer and a second sealant layer including crosslinked polypropylene, and the second sealant layer has a crosslinking degree of 52% to 80%. When the above pouch film laminate is sealed at 200° C. and 0.1 MPa for 3 seconds, the insulation resistance of the pouch film laminate may be 1000 MΩ or more. Specifically, the insulation resistance may be 1000 MΩ or more, 1100 MΩ or more, 1200 MΩ or more, 1300 MΩ or more, 1400 MΩ or more, 1500 MΩ or more, 1600 MΩ or more, or 1700 MΩ or more. When the above insulation resistance range is satisfied, the manufactured pouch-type battery case may have sufficient insulation, so that the secondary battery may be driven at a normal voltage, an internal short circuit of the battery may be prevented, the risk of explosion or ignition may be reduced, and the stability may be improved, and the risk of damage to the user's body may be reduced. The pouch film laminate according to the present invention may have a total thickness of 120 ㎛ to 250 ㎛, preferably 140 ㎛ to 230 ㎛, and more preferably 150 ㎛ to 215 ㎛. When the thickness of the pouch film laminate satisfies the above range, the forming depth can be increased while minimizing a decrease in the battery accommodation space and a decrease in sealing durability due to an increase in the thickness of the pouch laminate. At this time, the total thickness (D) of the two pouch film laminates before sealing A ) and two sheets of the above pouch film laminate were sealed at 200°C and 0.1 MPa for 3 seconds, and the total thickness (D) of the two sheets of the above pouch film laminate S ) of the ratio (D) S / DA ) can be from 0.2 to 0.6. Specifically, the DS / DA can be 0.2 or more, 0.25 or more, 0.3 or more, 0.35 or more, 0.4 or more, 0.4 or more, and 0.6 or less, 0.55 or less, 0.5 or less, 0.45 or less. When the above range is satisfied, the sealing property and insulation property of the sealed pouch-type battery case are excellent. Figures 1 and 2 are cross-sectional views showing the structure of a pouch film laminate according to an embodiment of the present invention. Referring to FIGS. 1 and 2, a pouch film laminate (100) according to one embodiment of the present invention includes a substrate layer (110), a gas barrier layer (120), and a sealant layer (130), and in the pouch film laminate (100), the substrate layer (110), the gas barrier layer (120), and the sealant layer (130) may be laminated in that order. The pouch film laminate according to the present invention can be manufactured through a method for manufacturing a pouch film laminate known in the art. For example, the pouch film laminate of the present invention can be manufactured through a method of attaching a substrate layer (110) to an upper surface of a gas barrier layer (120) through an adhesive, and forming a sealant layer (130) on a lower surface of the gas barrier layer (120) through coextrusion or an adhesive layer, and can be manufactured through a method such as dry lamination or sandwich lamination. However, the method for manufacturing the pouch film laminate is not limited thereto. Hereinafter, each layer included in the pouch film laminate will be described in detail with reference to FIGS. 1 and 2. (1) Substrate layer The substrate layer (110) is formed on the outermost layer of the pouch film laminate (100) to protect the secondary battery from friction and collision with the outside. The substrate layer (110) is made of polymer and can electrically insulate the electrode assembly from the outside. The substrate layer (110) 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, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, and Teflon. Among them, the substrate layer (110) is preferably made of polyethylene terephthalate (PET), nylon, or a combination thereof, which have wear resistance and heat resistance. The thickness of the substrate layer (110) may be 5 ㎛ to 100 ㎛, specifically 7 ㎛ to 70 ㎛, and more specifically 10 ㎛ to 60 ㎛. When the thickness of the substrate layer (110) satisfies the above range, the external insulation is excellent, and the thickness of the entire pouch is not thick, so the energy density per volume of the secondary battery can be excellent. The substrate layer (110) may have a single film structure made of a single material. Alternatively, the substrate layer (110) may have a composite film structure in which two or more materials are each formed as layers. In the composite film structure, an adhesive layer may be additionally arranged between each layer. Specifically, the substrate layer (110) according to the present invention may include a first substrate layer (112) and a second substrate layer (114). In this case, the first substrate layer (112) may be a layer disposed on the outermost layer of the pouch film laminate, and the second substrate layer (114) may be a layer disposed between the first substrate layer (112) and the gas barrier layer (120). The first substrate layer (112) and the second substrate layer (114) may each be formed of materials having different materials and / or different properties. An interface may exist between the first substrate layer (112) and the second substrate layer (114). This means that the first substrate layer (112) and the second substrate layer (114) are different layers, and may be formed separately. Hereinafter, each of the first substrate layer (112) and the second substrate layer (114) described above will be described in more detail. 1) 1st layer The first substrate layer (112) can serve to prevent moisture penetration from the outside of the pouch. The first substrate layer (112) can 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, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, and Teflon. Preferably, the first substrate layer (112) can include a polyester film having wear resistance and heat resistance. For example, the first substrate layer (112) can include at least one or more materials selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, but is not limited thereto. The thickness of the first substrate layer (112) may be 10 ㎛ to 50 ㎛, specifically 10 ㎛ to 40 ㎛, and more specifically 12 ㎛ to 25 ㎛. When the thickness of the first substrate layer (112) satisfies the above numerical range, the insulation and formability of the pouch can be secured while effectively suppressing moisture penetration into the interior of the pouch film laminate. In addition, since the thickness of the entire pouch is not thick, the energy density per volume of the secondary battery is excellent. 2) Second layer The second substrate layer (114) can play a role of improving the formability of the pouch. The second substrate layer (114) can include a polyamide-based film. For example, the second substrate layer (114) can include at least one selected from the group consisting of nylon 6, nylon 6,6, nylon MXD6 (polyxylylene adipamide), nylon 4, nylon 4,6, and nylon 4,10, but is not limited thereto. Preferably, the second substrate layer (114) can include nylon 6, and in this case, due to the excellent elongation properties of nylon 6, there is an advantage of improving the formability of the pouch. The thickness of the second substrate layer (114) can be 10 ㎛ to 50 ㎛, specifically, 10 ㎛ to 40 ㎛, and more specifically, 15 ㎛ to 35 ㎛. When the thickness of the second substrate layer (114) satisfies the above numerical range, the formability of the pouch can be secured while preventing a decrease in the energy density per volume of the secondary battery due to the thickness of the pouch film laminate becoming excessively thick. The second substrate layer (114) may include metal oxide particles. The metal oxide particles may remove moisture within the second substrate layer (114) by being hydroxylated by reaction with moisture introduced into the second substrate layer (114). The metal oxide particles may include at least one selected from the group consisting of CaO, MnO, SrO, MgO, and ZnO. Preferably, the metal oxide particles may include at least one of CaO and MgO, which are advantageous for hydroxylation with moisture. The second substrate layer (114) may further include an additive. By including an additive in the second substrate layer (114), the physical properties of the second substrate layer (114) may be changed. For example, as an additive for controlling the tensile strength of the second substrate layer (114), at least one of carbon fiber, glass fiber, and aramid fiber may be added. (2) Gas barrier layer The gas barrier layer (120) is laminated between the substrate layer (110) and the sealant layer (130) to secure the mechanical strength of the pouch, block the ingress of gas or moisture from outside the secondary battery, and prevent electrolyte leakage from inside the pouch-type battery case. The gas barrier layer (120) may be formed of a metal. For example, the gas barrier layer may be a metal thin film including at least one metal selected from the group consisting of aluminum (Al), copper (Cu), stainless steel (SUS), nickel (Ni), titanium (Ti), and invar (INVAR), but is not limited thereto. According to one embodiment of the present invention, the gas barrier layer (120) may be formed of an aluminum alloy thin film. When the gas barrier layer (120) is formed using an aluminum alloy thin film, a mechanical strength higher than a predetermined level can be secured, while being light in weight, and securing complementary and heat dissipation properties for electrochemical properties by the electrode assembly and the electrolyte. The aluminum alloy thin film may contain elements other than aluminum (Al). For example, the aluminum alloy thin film may contain at least one selected from the group consisting of iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), silicon (Si), and zinc (Zn). In another example, the gas barrier layer (120) may be formed of a stainless steel thin film. Specifically, the gas barrier layer (120) may be manufactured by molding and / or processing a stainless steel thin film. The gas barrier layer (120) formed of stainless steel has relatively low thermal conductivity, which is effective in preventing or delaying heat diffusion to other cells during thermal runaway, and has relatively high toughness, which can suppress cracking of the pouch during use of the pouch-type battery. The stainless steel may include at least one element other than iron (Fe), for example, copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), silicon (Si), and zinc (Zn). The thickness of the above gas barrier layer (120) may be 20 ㎛ to 100 ㎛, preferably 30 ㎛ to 90 ㎛, and more preferably 35 ㎛ to 85 ㎛. When the above range is satisfied, the present invention does not cause a problem of deformation of the substrate layer even when the sealing temperature is increased so that heat can be transferred to the sealant layer, so that the formability and gas barrier performance can be improved when forming the cup portion by using a gas barrier layer thicker than a conventional gas barrier layer. (3) Sealant layer The sealant layer (130) is intended to completely seal the inside of the pouch-shaped battery case by mutually thermally bonding the sealing portion when the pouch-shaped battery case containing the electrode assembly inside is sealed. The thickness of the sealant layer (130) may be 50 ㎛ to 140 ㎛, specifically 60 ㎛ to 130 ㎛, and more specifically 70 ㎛ to 120 ㎛. When the thickness of the sealant layer satisfies the above range, there is an effect of securing the sealing strength of the sealing portion while also securing the formability of the pouch film laminate. Meanwhile, the sealant layer (130) according to the present invention has a composite film structure in which two or more materials are formed to form layers. For example, the sealant layer (130) may have a multilayer structure. An adhesive layer and / or a skin layer may be arranged between each layer of the sealant layer (130) having the composite film structure. The adhesive layer and / or the skin layer may have thermal adhesiveness and thus may play a role in assisting adhesion between each layer of the sealant layer (130). For example, the adhesive layer and / or the skin layer may include a polypropylene-based resin, but is not limited thereto. In addition, the adhesive layer and / or the skin layer may be arranged between the sealant layer (130) and the gas barrier layer (120). Specifically, the sealant layer (130) according to the present invention includes a first sealant layer (132) and a second sealant layer (134). As another example, the sealant layer (130) may further include a third sealant layer (136) and / or a fourth sealant layer (138) in addition to the first sealant layer (132) and the second sealant layer (134). Each layer of the sealant layer (130) including the first sealant layer (132) and the second sealant layer (134) may be formed of a material having different materials and / or different properties. An interface may exist between each layer included in the sealant layer (130). This means that each layer is a different layer and may be formed separately. Specifically, in the pouch film laminate according to the present invention, the sealant layer includes a first sealant layer (132) including a polypropylene random copolymer and a second sealant layer (134) including cross-linked polypropylene. When the sealant layer of the first case and the sealant layer of the second case come into contact with each other in the sealing portion and are thermally bonded to each other to form a seal, the sealant layer must completely seal the pouch-type battery case so that the electrolyte inside the pouch-type battery case does not leak to the outside of the pouch-type battery case and protect the secondary battery from external impact or moisture penetration. In addition, since it comes into direct contact with the electrode assembly and / or electrolyte inside the pouch-type battery case, it must have insulating properties and corrosion resistance. To this end, the sealant layer must have excellent thermal bonding strength and insulation resistance so that the pouch-type battery case has sufficient sealing properties, insulating properties, and corrosion resistance. In order for the above sealant layer to have excellent thermal bonding strength, a sufficient amount of heat must be applied during sealing so that the sealant layer is sufficiently melted and the sealant layers can be strongly adhered to each other. At this time, as a method for applying more heat during sealing of the pouch-type battery case, the sealing temperature and / or sealing time can be increased. However, if the sealing temperature is increased, the moisture contained in the substrate layer may evaporate, causing deformation of the substrate layer, which may result in defects in the appearance of the pouch-type battery case, and thus, deterioration of the battery quality. Accordingly, conventionally, a polypropylene homocopolymer or a polypropylene block copolymer was generally included in the sealant layer, and the sealing time was increased to improve the sealing strength of the pouch-type battery case. However, in this case, since the time required for sealing increases, the time required for the manufacturing process of the secondary battery increases as a result, and accordingly, there is a problem that the processability and productivity of the secondary battery are reduced. Therefore, the pouch film laminate according to the present invention includes a polypropylene random copolymer rather than a polypropylene homocopolymer or a polypropylene block copolymer in the first sealant layer, thereby sufficiently securing the sealing strength of the pouch-type secondary battery while shortening the time required for sealing. However, when the sealant layer only includes a polypropylene random copolymer, when an excessive amount of heat is applied to the sealing portion during the sealing process of the pouch-type secondary battery, the sealant layer may melt, thereby changing the arrangement of the polypropylene random copolymer, and accordingly, there may be a problem in that the thickness of the sealant layer is significantly reduced. If the thickness of the sealant layer is reduced, the problem of corrosion due to the sealant layer coming into contact with the electrolyte and the electrolyte penetrating into the sealant layer may be aggravated. In addition, when the insulation resistance of the sealing portion is reduced below a certain level, the insulation of the pouch-type battery case deteriorates, which may result in a risk of short circuit, explosion, or ignition inside the battery and may cause serious damage to the user's body. Therefore, the pouch film laminate according to the present invention includes a second sealant layer including a cross-linked polypropylene together with the first sealant layer including a polypropylene random copolymer, so that even if a large amount of heat is applied to the sealing portion during the sealing process of the pouch-type secondary battery and it is compressed, the phenomenon of the polymer components being deformed and the thickness and insulation resistance of the sealant layer being excessively reduced can be prevented, thereby sufficiently securing the insulation and corrosion resistance of the manufactured pouch-type battery case. The first sealant layer (132) and the second sealant layer (134) may be sequentially laminated, or the second sealant layer (134) and the first sealant layer (132) may be sequentially laminated. When a third sealant layer (136) is additionally included, the third sealant layer (136) may be positioned at the outermost portion of the sealant layers, and the first sealant layer (132), the second sealant layer (134), and the third sealant layer (136) may be sequentially laminated, or the second sealant layer (134), the first sealant layer (132), and the third sealant layer (136) may be sequentially laminated. The ratio (A / B) of the thickness (A) of the first sealant layer (132) to the thickness (B) of the second sealant layer (134) may be 0.6 to 1.5. Specifically, the ratio (A / B) of the thickness (A) of the first sealant layer (132) to the thickness (B) of the second sealant layer (134) may be 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, and may be 1.5 or less, 1.4 or less, 1.3 or less, 1.2 or less, or 1.1 or less. When the above range is satisfied, the manufactured pouch-type battery case may have excellent sealing properties, corrosion resistance, and insulation properties, and at the same time, the sealing time may be shortened, thereby improving the productivity of the secondary battery. Below, each layer of the sealant layer is described in detail. 1) First sealant layer The first sealant layer (132) includes a polypropylene random copolymer. Here, the polypropylene random copolymer means a copolymer containing propylene as a copolymer component and other copolymer components except for propylene. Specifically, the first sealant layer (132) may include at least one selected from the group consisting of an ethylene-propylene random copolymer and a butene-propylene random copolymer, and preferably may include an ethylene-propylene random copolymer. When the first sealant layer includes a polypropylene random copolymer, the melt flow rate (MFR) is high and the melting point is low, so that when the same amount of heat is applied, the desired sealing thickness can be quickly achieved. Accordingly, even without increasing the sealing temperature, the sealing time can be shortened compared to when a polypropylene homo copolymer is included, and the process time of the secondary battery can be shortened, thereby improving productivity and processability, and at the same time, since it has strong thermal bonding strength, the pouch-type battery case can have excellent sealing properties. The ethylene monomer of the polypropylene random copolymer may be included in an amount of 5 wt% to 50 wt% based on the total weight of the first sealant layer (132). Specifically, the ethylene monomer of the polypropylene random copolymer may be included in an amount of 5 wt% or more, 7 wt% or more, 10 wt% or more, 12 wt% or more, 15 wt% or more, or 17 wt% or more, and may be included in an amount of 50 wt% or less, 45 wt% or less, 40 wt% or less, 35 wt% or less, 30 wt% or less, 25 wt% or less, or 20 wt% or less, based on the total weight of the first sealant layer (132). For example, based on the total weight of the first sealant layer (132), the ethylene monomer of the polypropylene random copolymer may be included in an amount of 5 wt% to 50 wt%, preferably 10 wt% to 30 wt%, more preferably 12 wt% to 25 wt%, and even more preferably 15 wt% to 20 wt%. When the above range is satisfied, the sealant layer can be quickly melted and sealed during the sealing process, thereby shortening the sealing time while having excellent thermal bonding strength. The melting temperature of the first sealant layer (132) may be 120°C to 150°C. Specifically, the melting temperature of the first sealant layer (132) may be 120°C or higher, 125°C or higher, 130°C or higher, 135°C or higher, and 150°C or lower, 145°C or lower, or 140°C or lower. When the melting temperature is satisfied, the sealant layer may be sufficiently melted within the sealing process temperature to have excellent sealing properties. The thickness of the first sealant layer (132) may be 10 ㎛ to 90 ㎛, specifically 10 ㎛ to 60 ㎛, and more specifically 10 ㎛ to 40 ㎛. When the thickness of the first sealant layer (132) satisfies the above range, the pouch-type battery case manufactured from the pouch film laminate has excellent sealing durability and insulation, and may have excellent sealing strength. In addition, the extrusion process of the pouch film laminate can be performed with a uniform thickness, and the problem of the energy density of the manufactured pouch-type secondary battery being reduced can be prevented. According to one embodiment of the present invention, the first sealant layer (132) may be a layer that is in direct contact with the gas barrier layer (120) or may not be in direct contact. When in direct contact with the gas barrier layer (120), the first sealant layer (132) may be directly adhered to the gas barrier layer (120) when the pouch film laminate (100) is co-extruded. In another example, an adhesive layer and / or a skin layer may be disposed between the first sealant layer (132) and the gas barrier layer (120) to improve the adhesion between the first sealant layer (132) and the gas barrier layer (120). When not in direct contact with the gas barrier layer (120), a second sealant layer (134) may be disposed between the first sealant layer (132) and the gas barrier layer (120). 2) Second sealant layer The second sealant layer (134) may be formed of a material having insulating, corrosion-resistant, and sealing properties. Specifically, since the second sealant layer (134) is in direct contact with the electrode assembly (260 of FIG. 3) and / or the electrolyte inside the receiving space (224 of FIG. 3), it may be formed of a material having insulating and corrosion-resistant properties. In addition, since the second sealant layer (134) must completely seal the inside of the battery case to block material movement between the inside and the outside, it may be formed of a material having high sealing properties. The second sealant layer (134) may include crosslinked polypropylene. The crosslinked polypropylene may have a structure in which polypropylene linear chains are linked to each other at multiple locations by covalent bonds, and the crosslinked polypropylene may include partially crosslinked polypropylene. Specifically, the second sealant layer may include crosslinked homopolypropylene. According to the present invention, by including cross-linked polypropylene in the second sealant layer (134), even if a large amount of heat is applied to the sealant layer when sealing a pouch film laminate, the distance between the polypropylene chains of the cross-linked polypropylene can be maintained within a certain range due to the covalent bond between the polypropylene chains of the cross-linked polypropylene even when heat and pressure are applied. Accordingly, even if over-sealing occurs during the sealing process of the pouch film laminate, the sealant layer can be maintained at a certain thickness or more, and accordingly, even if the sealant layer comes into contact with the electrolyte contained inside the battery case, corrosion resistance can be maintained, and the insulation resistance of the sealed pouch-type battery case can be a certain amount or more, so that insulation and corrosion resistance can be secured. Accordingly, there is an advantage in that the stability and battery performance of the manufactured pouch-type secondary battery can be secured. The crosslinked polypropylene may have a crosslinking degree of 52% to 80%. Specifically, the crosslinked polypropylene may have a crosslinking degree of 52% or more, 55% or more, 57% or more, or 60% or more, and 80% or less, 75% or less, 70% or less, 65% or less, or 60% or less. When the crosslinking degree is less than 52%, the crosslinking property of the crosslinked polypropylene is low, so that when a large amount of heat is applied to the sealant layer, the distance between the polypropylene chains may not be maintained, and thus the thickness of the sealant layer may be significantly reduced after sealing, and thus there may be a problem of deterioration in the insulation of the pouch-type battery case. When the crosslinking degree is greater than 80%, the thickness of the sealant layer does not significantly decrease when the pouch-type battery case is sealed, but delamination may occur at interfaces of the second sealant layer, and thus there may be problems in the insulation, corrosion resistance, and sealing properties of the pouch-type battery case. Therefore, when the cross-linking degree satisfies 52% to 80%, the manufactured pouch-type battery case can have excellent insulation properties while preventing delamination between interfaces of the sealant layers. The crosslinking degree of the above crosslinked polypropylene can be controlled within an appropriate range by controlling the content of the crosslinking agent added. Specifically, the crosslinking agent may be a tin-based compound, specifically an organic tin-based compound, and more specifically an octyltin-based compound and / or a butyltin-based compound. The melting temperature of the second sealant layer (134) may be 120°C to 150°C. Specifically, the melting temperature of the second sealant layer (134) may be 120°C or higher, 125°C or higher, 130°C or higher, 135°C or higher, and 150°C or lower, 145°C or lower, or 140°C or lower. When the melting temperature is satisfied, the sealant layer may be sufficiently melted within the sealing process temperature to have excellent sealing properties. The thickness of the second sealant layer (134) may be 10 ㎛ to 90 ㎛, specifically 10 ㎛ to 60 ㎛, and more specifically 10 ㎛ to 40 ㎛. When the thickness of the second sealant layer (134) satisfies the above range, the sealing durability and insulation of the pouch-type battery case manufactured from the pouch film laminate may be excellent, and may have excellent sealing strength. In addition, the extrusion process of the pouch film laminate may be performed with a uniform thickness, and the problem of the energy density of the manufactured pouch-type secondary battery being reduced may be prevented. According to one embodiment of the present invention, the second sealant layer (134) may be in direct contact with the gas barrier layer (120) or may not be in direct contact. In the case of direct contact, when the pouch film laminate (100) is co-extruded, the second sealant layer (134) may be directly adhered to the gas barrier layer (120). In another example, an adhesive layer and / or a skin layer may be disposed between the second sealant layer (134) and the gas barrier layer (120) to improve the adhesion between the second sealant layer (134) and the gas barrier layer (120). In the case of not being in direct contact with the gas barrier layer (120), a first sealant layer (132) may be disposed between the second sealant layer (134) and the gas barrier layer (120). The second sealant layer (134) may be arranged to be in direct contact with the first sealant layer (132), or may not be in direct contact with it. When the second sealant layer (134) and the first sealant layer (132) are not in direct contact, the pouch film laminate may further include one or more layers arranged between the first sealant layer (132) and the second sealant layer (134). For example, an intermediate layer (not shown) may be arranged between the first sealant layer (132) and the second sealant layer (134) to improve the insulation of the pouch film laminate. The intermediate layer may include at least one of polypropylene and homo polypropylene. The thickness of the intermediate layer may be 80 ㎛ or less, specifically, 10 ㎛ to 60 ㎛, and more specifically, 10 ㎛ to 30 ㎛. When the thickness of the intermediate layer satisfies the above numerical range, the coextrusion moldability of the sealant layer is improved while ensuring excellent sealing strength. 3) Third sealant layer The above sealant layer may further include a third sealant layer (136) at the outermost layer. At this time, the third sealant layer (136) may be a material having high thermal bonding strength as a layer that contacts the sealant layers when sealing the pouch film laminate. The third sealant layer may include a polypropylene random copolymer. Specifically, the third sealant layer may include at least one selected from the group consisting of an ethylene-propylene random copolymer and a butene-propylene random copolymer, and preferably may include an ethylene-propylene random copolymer. When the third sealant layer includes a polypropylene random copolymer, since the melt flow rate (MFR) is high and the melting point is low, when the same amount of heat is applied, the desired sealing thickness can be quickly achieved. Accordingly, even without increasing the sealing temperature, the sealing time can be shortened compared to the case where a polypropylene homo copolymer is included, and the process time of the secondary battery can be shortened, thereby improving productivity and processability, and at the same time having strong thermal bonding strength, the pouch-type battery case can have excellent sealing properties. The thickness of the third sealant layer may be 5 ㎛ to 50 ㎛, specifically 5 ㎛ to 30 ㎛, and more specifically 7 ㎛ to 20 ㎛. When the thickness of the third sealant layer satisfies the above range, the pouch-type battery case manufactured from the pouch film laminate has excellent sealing durability and insulation, and can have excellent sealing strength. In addition, the extrusion process of the pouch film laminate can be performed with a uniform thickness, and the problem of the energy density of the manufactured pouch-type secondary battery being reduced can be prevented. The third sealant layer may be arranged to be in direct contact with the second sealant layer, or may not be in direct contact with it. When the third sealant layer and the second sealant layer (134) are not in direct contact, the pouch film laminate may further include one or more layers arranged between the second sealant layer (134) and the third sealant layer. For example, an intermediate layer (not shown) may be arranged between the second sealant layer (134) and the third sealant layer to improve the insulation of the pouch film laminate. The intermediate layer may include at least one of polypropylene and homo polypropylene. The thickness of the intermediate layer may be 80 ㎛ or less, specifically, 10 ㎛ to 60 ㎛, and more specifically, 10 ㎛ to 30 ㎛. When the thickness of the intermediate layer satisfies the above numerical range, the coextrusion moldability of the sealant layer is improved while ensuring excellent sealing strength. 4) 4th sealant layer The above sealant layer may further include a fourth sealant layer (138) between the gas barrier layer and the first sealant layer. At this time, the fourth sealant layer (138) may be a material having high peel strength at the interface between the gas barrier layer and the sealant layer. The fourth sealant layer may include a polypropylene random copolymer. Specifically, the fourth sealant layer may include at least one selected from the group consisting of an ethylene-propylene random copolymer and a butene-propylene random copolymer, and preferably may include an ethylene-propylene random copolymer. When the fourth sealant layer includes a polypropylene random copolymer, the peel strength at the interface between the gas barrier layer and the sealant layer can be improved. The thickness of the fourth sealant layer may be 5 ㎛ to 50 ㎛, specifically 5 ㎛ to 30 ㎛, and more specifically 7 ㎛ to 20 ㎛. When the thickness of the fourth sealant layer satisfies the above range, the pouch-type battery case manufactured from the pouch film laminate has excellent sealing durability and insulation, and can have excellent sealing strength. In addition, the extrusion process of the pouch film laminate can be performed with a uniform thickness, and the problem of the energy density of the manufactured pouch-type secondary battery being reduced can be prevented. The fourth sealant layer may be arranged to be in direct contact with the first sealant layer, or may not be in direct contact with it. When the fourth sealant layer and the first sealant layer (132) are not in direct contact, the pouch film laminate may further include one or more layers arranged between the second sealant layer (134) and the third sealant layer. For example, an intermediate layer (not shown) may be arranged between the first sealant layer (132) and the fourth sealant layer (138) to improve the insulation of the pouch film laminate. The intermediate layer may include at least one of polypropylene and homo polypropylene. The thickness of the intermediate layer may be 80 ㎛ or less, specifically, 10 ㎛ to 60 ㎛, and more specifically, 10 ㎛ to 30 ㎛. When the thickness of the intermediate layer satisfies the above numerical range, the coextrusion moldability of the sealant layer is improved while ensuring excellent sealing strength. Pouch-type battery case Figure 3 is an exploded assembly drawing of a pouch-type secondary battery (200) according to the present invention. Referring to FIG. 3, a pouch-shaped battery case (210) can be manufactured by molding the pouch film laminate of the present invention described above. The pouch-shaped battery case (210) can accommodate an electrode assembly (260) inside. Since the detailed configuration and properties of the pouch film laminate are the same as described above, a detailed description is omitted. The pouch film laminate may be drawn and stretched by a punch or the like to manufacture a pouch-shaped battery case (210). As a result, the pouch-shaped battery case (210) may include a cup portion (222) and a receiving portion (224). The receiving portion (224) is a place for receiving an electrode assembly, and may mean a receiving space formed in a pocket shape on the inside of the cup portion (222) as the cup portion (222) is formed. According to one embodiment of the present invention, the pouch-type battery case (210) may include a first case (220) and a second case (230) as illustrated in FIG. 3. The first case (220) includes a receiving portion (224) capable of receiving an electrode assembly (260), and the second case (230) may cover the receiving portion (224) from above to prevent the electrode assembly (260) from being separated from the outside of the battery case (210). The first case (220) and the second case (230) may be manufactured such that one side thereof is connected to each other as illustrated in FIG. 3, but are not limited thereto and may be manufactured in various ways, such as being manufactured separately from each other. According to another embodiment of the present invention, when forming a cup portion in a pouch film laminate, two symmetrical cup portions (222, 232) can be drawn and formed adjacent to each other in one pouch film laminate. In this case, cup portions (222, 232) can be formed in each of the first case (220) and the second case (230) as illustrated in FIG. 3. After the electrode assembly (260) is accommodated in the receiving portion (224) provided in the cup portion (222) of the first case (220), the bridge portion (240) formed between the two cup portions (222, 232) can be folded so that the two cup portions (222, 232) face each other. In this case, the cup portion (232) of the second case (230) can accommodate the electrode assembly (260) from above. Accordingly, since two cup parts (222, 232) accommodate one electrode assembly (260), an electrode assembly (260) having a thicker thickness can be accommodated than when there is only one cup part (222). In addition, since one corner of the secondary battery (200) is formed by folding the pouch-type battery case (210), the number of corners to be sealed can be reduced when performing a sealing process later. Accordingly, the process speed of the pouch-type secondary battery (200) can be improved, and the number of sealing processes can be reduced. The pouch-type battery case (210) can be sealed while housing the electrode assembly (260) so that a part of the electrode lead (280) described later, i.e., a terminal part, is exposed. Specifically, when the electrode lead (280) is connected to the electrode tab (270) of the electrode assembly (260) and an insulating part (290) is formed on a part of the electrode lead (280), the electrode assembly (260) can be housed in the receiving part (224) provided in the cup part (222) of the first case (220), and the second case (230) can cover the receiving part (224) from above. Then, an electrolyte can be injected into the interior of the receiving part (224), and the sealing part (250) formed on the edges of the first case (220) and the second case (230) can be sealed. The sealing portion (250) can perform a function of sealing the receiving portion (224). Specifically, the sealing portion (250) can seal the receiving portion (224) while being formed along the edge of the receiving portion (224). The temperature for sealing the sealing portion (250) can be 180° C. to 250° C., specifically 200° C. to 250° C., and more specifically 210° C. to 240° C. When the sealing temperature satisfies the above numerical range, the pouch-type battery case (210) can secure sufficient sealing strength by heat bonding. Pouch-type secondary battery Next, a pouch-type secondary battery according to the present invention will be described. As illustrated in FIG. 3, a pouch-type secondary battery (200) according to the present invention may include a pouch-type battery case (210) manufactured by molding the aforementioned pouch film laminate, and an electrode assembly (260) housed in the pouch-type battery case (210). Specifically, the pouch-type secondary battery (200) of the present invention may include a pouch-type battery case (210), an electrode assembly (260), an electrode lead (280), an insulator (290), and an electrolyte (not shown). Hereinafter, each component of the pouch-type secondary battery of the present invention will be described in more detail with reference to FIG. 3. (1) Pouch-type battery case Since each component of the pouch-type battery case is the same as described above, a detailed description is omitted. (2) Electrode assembly The electrode assembly (260) can be inserted into a pouch-shaped battery case (210) and sealed by the pouch-shaped battery case (210) after electrolyte injection. The electrode assembly (260) may be formed by sequentially stacking an anode, a separator, and a cathode. Specifically, the electrode assembly (260) may include two types of electrodes, an anode and a cathode, and a separator interposed between the electrodes to mutually insulate the electrodes. The positive and negative electrodes may each have a structure in which an active material slurry is applied to an electrode current collector in the form of a metal foil or metal mesh containing aluminum and copper, respectively. The slurry may be formed by stirring a granular active material, an auxiliary conductor, a binder, and a conductive agent while a solvent is added. The solvent may be removed in a subsequent process. A slurry containing an electrode active material and a binder and / or a conductive material is applied to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode, and the positive electrode and negative electrode are laminated on both sides of a separator, thereby manufacturing an electrode assembly (260) in a predetermined shape. The types of the electrode assembly (260) may include, but are not limited to, a stack type, a jelly roll type, a stack and folding type, etc. The electrode assembly (260) may include an electrode tab (270). The electrode tabs (270) are respectively connected to the positive and negative electrodes of the electrode assembly (260), and may protrude outwardly from the electrode assembly (260) to serve as a path through which electrons may move between the inside and the outside of the electrode assembly (260). The electrode current collector included in the electrode assembly (260) may be composed of a portion where an electrode active material is applied and a terminal portion where the electrode active material is not applied, i.e., a non-coated portion. The electrode tabs (270) may be formed by cutting the non-coated portion or by connecting a separate conductive member to the non-coated portion by ultrasonic welding, etc. As illustrated in FIG. 3, the electrode tabs (270) may protrude in different directions from each other in the electrode assembly (260), but are not limited thereto, and may be formed to protrude in various directions, such as protruding side by side in the same direction from one side. (3) Electrode lead The electrode lead (280) can supply electricity to the outside of the secondary battery (200). The electrode lead (280) can be connected to the electrode tab (270) of the electrode assembly (260) by spot welding, etc. The electrode lead (280) is connected to the electrode assembly (260) and may protrude to the outside of the pouch-type battery case (210) via the sealing portion (250). Specifically, one end of the electrode lead (280) is connected to the electrode assembly (260), particularly to the electrode tab (270), and the other end of the electrode lead (280) may protrude to the outside of the pouch-type battery case (210). The electrode lead (280) may include a positive lead (282) having one end connected to the positive tab (272) and extending in the protruding direction of the positive tab (272), and a negative lead (284) having one end connected to the negative tab (274) and extending in the protruding direction of the negative tab (274). Both the positive lead (282) and the negative lead (284) may have other ends protruding outward from the battery case (210). Accordingly, electricity generated inside the electrode assembly (260) may be supplied to the outside. In addition, since the positive tab (272) and the negative tab (274) are formed to protrude in various directions, the positive lead (282) and the negative lead (284) may also extend in various directions, respectively. The positive lead (282) and the negative lead (284) may be made of different materials. That is, the positive electrode lead (282) may be made of the same aluminum (Al) material as the positive electrode collector, and the negative electrode lead (284) may be made of the same copper (Cu) material as the negative electrode collector or a copper material coated with nickel (Ni). A portion of the electrode lead (280) protruding outside the battery case (210) may be a terminal portion and may be electrically connected to an external terminal. (4) Insulation The insulating portion (290) prevents electricity generated from the electrode assembly (260) from flowing to the battery case (210) through the electrode lead (280) and can maintain the sealing of the battery case (210). To this end, the insulating portion (290) can be formed of a non-conductive material that does not conduct electricity well. In general, the insulating portion (290) is often made of an insulating tape or film that is easy to attach to the electrode lead (280) and has a relatively thin thickness, but is not limited thereto, and any material capable of insulating the electrode lead (280) can be used. The insulating portion (290) may be arranged to surround the outer surface of the electrode lead (280). Specifically, at least a portion of the electrode lead (280) may be surrounded by the insulating portion (290). In this case, the insulating portion (290) may be arranged between the electrode lead (280) and the pouch-type battery case (210). The insulating portion (290) may be positioned limited to the sealing portion (250) where the first case (220) and the second case (230) of the pouch-type battery case (210) are heat-sealed, and may adhere the electrode lead (280) to the battery case (210). (5) Electrolyte The pouch-type secondary battery (200) according to the present invention may further include an electrolyte (not shown) that is poured into the pouch-type battery case (210). The electrolyte is for moving lithium ions generated by an electrochemical reaction of an electrode during charging / discharging of the secondary battery (200), and may include a non-aqueous organic electrolyte that is a mixture of a lithium salt and an organic solvent, or a polymer using a polymer electrolyte. Furthermore, the electrolyte may include a solid electrolyte of a sulfide type, an oxide type, or a polymer type, and such a solid electrolyte may have flexibility that is easily deformed by an external force. Examples and Comparative Examples Example 1: Preparation of pouch film laminate On one surface of a 40 ㎛ thick aluminum film, a 3 ㎛ thick first adhesive film, a 15 ㎛ thick nylon film, a 3 ㎛ thick second adhesive film, and a 12 ㎛ thick polyethylene terephthalate (PET) film were sequentially laminated. On the other surface of the aluminum film, a 10 ㎛ thick ethylene-propylene random copolymer film (fourth sealant layer), a 30 ㎛ thick ethylene-propylene random copolymer film (first sealant layer), a 30 ㎛ thick cross-linked homo polypropylene film (second sealant layer), and a 10 ㎛ thick ethylene-propylene random copolymer film (third sealant layer) were sequentially laminated by coextrusion. At this time, the ethylene monomer was contained in the ethylene-propylene random copolymer film (first sealant layer) at 15 wt%, and the crosslinking degree of the cross-linked homo polypropylene in the cross-linked homo polypropylene film (second sealant layer) was 60%. As a result, a pouch film laminate having a structure in which polyethylene terephthalate / second adhesive film / nylon film / first adhesive film / aluminum thin film / ethylene-propylene random copolymer film (fourth sealant layer) / ethylene-propylene random copolymer film (first sealant layer) / cross-linked homopolypropylene film (second sealant layer) / ethylene-propylene random copolymer film (third sealant layer) are sequentially laminated was manufactured. Example 2: Preparation of pouch film laminate On one surface of a 40 ㎛ thick aluminum film, a 3 ㎛ thick first adhesive film, a 15 ㎛ thick nylon film, a 3 ㎛ thick second adhesive film, and a 12 ㎛ thick polyethylene terephthalate (PET) film were sequentially laminated. On the other surface of the aluminum film, a 10 ㎛ thick ethylene-propylene random copolymer film (fourth sealant layer), a 20 ㎛ thick ethylene-propylene random copolymer film (first sealant layer), a 40 ㎛ thick cross-linked homo polypropylene film (second sealant layer), and a 10 ㎛ thick ethylene-propylene random copolymer film (third sealant layer) were sequentially laminated by coextrusion. At this time, the ethylene monomer was contained in the ethylene-propylene random copolymer film (first sealant layer) at 15 wt%, and the crosslinking degree of the cross-linked homo polypropylene in the cross-linked homo polypropylene film (second sealant layer) was 60%. As a result, a pouch film laminate having a structure in which polyethylene terephthalate / second adhesive film / nylon film / first adhesive film / aluminum thin film / ethylene-propylene random copolymer film (fourth sealant layer) / ethylene-propylene random copolymer film (first sealant layer) / cross-linked homopolypropylene film (second sealant layer) / ethylene-propylene random copolymer film (third sealant layer) are sequentially laminated was manufactured. Example 3: Preparation of pouch film laminate On one surface of a 40 ㎛ thick aluminum film, a 3 ㎛ thick first adhesive film, a 15 ㎛ thick nylon film, a 3 ㎛ thick second adhesive film, and a 12 ㎛ thick polyethylene terephthalate (PET) film were sequentially laminated. On the other surface of the aluminum film, a 10 ㎛ thick ethylene-propylene random copolymer film (fourth sealant layer), a 40 ㎛ thick ethylene-propylene random copolymer film (first sealant layer), a 20 ㎛ thick cross-linked homo polypropylene film (second sealant layer), and a 10 ㎛ thick ethylene-propylene random copolymer film (third sealant layer) were sequentially laminated by coextrusion. At this time, the ethylene monomer was contained at 15 wt% in the ethylene-propylene random copolymer film (first sealant layer), and the crosslinking degree of the cross-linked homo polypropylene in the cross-linked homo polypropylene film (second sealant layer) was 60%. As a result, a pouch film laminate having a structure in which polyethylene terephthalate / second adhesive film / nylon film / first adhesive film / aluminum thin film / ethylene-propylene random copolymer film (fourth sealant layer) / ethylene-propylene random copolymer film (first sealant layer) / cross-linked homopolypropylene film (second sealant layer) / ethylene-propylene random copolymer film (third sealant layer) are sequentially laminated was manufactured. Comparative Example 1: Manufacturing of pouch film laminate On one side of a 40 ㎛ thick aluminum film, a 3 ㎛ thick first adhesive film, a 15 ㎛ thick nylon film, a 3 ㎛ thick second adhesive film, and a 12 ㎛ thick polyethylene terephthalate (PET) film were sequentially laminated. On the other side of the aluminum film, a 10 ㎛ thick ethylene-propylene random copolymer film, a 60 ㎛ thick polypropylene homo-copolymer film, and a 10 ㎛ thick ethylene-propylene random copolymer film were sequentially laminated by coextrusion. As a result, a pouch film laminate having a structure in which polyethylene terephthalate / second adhesive film / nylon film / first adhesive film / aluminum thin film / ethylene-propylene random copolymer film / polypropylene homo copolymer film / ethylene-propylene random copolymer film are sequentially laminated was manufactured. Comparative Example 2: Manufacturing of Pouch Film Laminate On one side of a 40 ㎛ thick aluminum film, a 3 ㎛ thick first adhesive film, a 15 ㎛ thick nylon film, a 3 ㎛ thick second adhesive film, and a 12 ㎛ thick polyethylene terephthalate (PET) film were sequentially laminated. On the other side of the aluminum film, a 10 ㎛ thick ethylene-propylene random copolymer film, a 60 ㎛ thick ethylene-propylene random copolymer film, and a 10 ㎛ thick ethylene-propylene random copolymer film were sequentially laminated by coextrusion. The ethylene monomer was contained in an amount of 15 wt% in the ethylene-propylene random copolymer film. As a result, a pouch film laminate having a structure in which polyethylene terephthalate / second adhesive film / nylon film / first adhesive film / aluminum thin film / ethylene-propylene random copolymer film / ethylene-propylene random copolymer film / ethylene-propylene random copolymer film are sequentially laminated was manufactured. Comparative Example 3: Manufacturing of pouch film laminate On one surface of a 40 ㎛ thick aluminum film, a 3 ㎛ thick first adhesive film, a 15 ㎛ thick nylon film, a 3 ㎛ thick second adhesive film, and a 12 ㎛ thick polyethylene terephthalate (PET) film were sequentially laminated. On the other surface of the aluminum film, an ethylene-propylene random copolymer film having a thickness of 10 ㎛, an ethylene-propylene random copolymer film having a thickness of 30 ㎛, a 30 ㎛ thick cross-linked homo polypropylene film, and a 10 ㎛ thick ethylene-propylene random copolymer film were sequentially laminated by coextrusion. At this time, the ethylene monomer was contained in the ethylene-propylene random copolymer film at 15 wt%, and the crosslinking degree of the cross-linked homo polypropylene in the cross-linked homo polypropylene film was 50%. As a result, a pouch film laminate having a structure in which polyethylene terephthalate / second adhesive film / nylon film / first adhesive film / aluminum thin film / ethylene-propylene random copolymer film / crosslinked homopolypropylene film / ethylene-propylene random copolymer film are sequentially laminated was manufactured. Comparative Example 4: Manufacturing of Pouch Film Laminate On one side of a 40 ㎛ thick aluminum film, a 3 ㎛ thick first adhesive film, a 15 ㎛ thick nylon film, a 3 ㎛ thick second adhesive film, and a 12 ㎛ thick polyethylene terephthalate (PET) film were sequentially laminated. On the other side of the aluminum film, an ethylene-propylene random copolymer film having a thickness of 10 ㎛, an ethylene-propylene random copolymer film having a thickness of 30 ㎛, a crosslinked homo-polypropylene film having a thickness of 30 ㎛, and an ethylene-propylene random copolymer film having a thickness of 10 ㎛ were sequentially laminated by coextrusion. At this time, the ethylene monomer was contained in the ethylene-propylene random copolymer film at 15 wt%, and the crosslinking degree of the crosslinked homo-polypropylene in the crosslinked homo-polypropylene film was 85%. As a result, a pouch film laminate having a structure in which polyethylene terephthalate / second adhesive film / nylon film / first adhesive film / aluminum thin film / ethylene-propylene random copolymer film / crosslinked homopolypropylene film / ethylene-propylene random copolymer film are sequentially laminated was manufactured. Comparative Example 5: Manufacturing of Pouch Film Laminate On one surface of a 40 ㎛ thick aluminum film, a 3 ㎛ thick first adhesive film, a 15 ㎛ thick nylon film, a 3 ㎛ thick second adhesive film, and a 12 ㎛ thick polyethylene terephthalate (PET) film were sequentially laminated. On the other surface of the aluminum film, a 10 ㎛ thick ethylene-propylene random copolymer film, a 30 ㎛ thick polypropylene homo copolymer film, a 30 ㎛ thick crosslinked homo polypropylene film, and a 10 ㎛ thick ethylene-propylene random copolymer film were sequentially laminated by coextrusion. At this time, the crosslinking degree of the crosslinked homo polypropylene in the crosslinked homo polypropylene film was 60%. As a result, a pouch film laminate having a structure in which polyethylene terephthalate / second adhesive film / nylon film / first adhesive film / aluminum thin film / ethylene-propylene random copolymer film / crosslinked homopolypropylene film / ethylene-propylene random copolymer film are sequentially laminated was manufactured. The laminated structures of the sealant layers of Examples 1 to 3 and Comparative Examples 1 to 5 manufactured above are shown in Table 1 below. In this case, Table 1 below shows the laminated films of the sealant layers by indicating them in order from the layer closest to the aluminum thin film to the outermost layer as 1 to 4. Sealant layer 1 (type / thickness) 2 (type / thickness / ethylene monomer content) 3 (type / thickness / crosslinking degree) 4 (type / thickness) Example 1 Ethylene-propylene random copolymer / 10 μm / ethylene-propylene random copolymer / 30 μm / 15 wt% crosslinked homo polypropylene / 30 μm / 60% Ethylene-propylene random copolymer / 10 μm Example 2 Ethylene-propylene random copolymer / 10 μm / ethylene-propylene random copolymer / 20 μm / 15 wt% crosslinked homo polypropylene / 40 μm / 60% Ethylene-propylene random copolymer / 10 μm Example 3 Ethylene-propylene random copolymer / 10 μm / ethylene-propylene random copolymer / 40 μm / 15 wt% crosslinked homo polypropylene / 20 μm / 60% Ethylene-propylene random copolymer / 10 μm Comparative example 1 Ethylene-propylene random Copolymer / 10㎛Polypropylene homo copolymer / 60㎛Ethylene-propylene random copolymer / 10㎛Comparative example 2Ethylene-propylene random copolymer / 10㎛Ethylene-propylene random copolymer / 60㎛ / 15 wt%Ethylene-propylene random copolymer / 10㎛Comparative example 3Ethylene-propylene random copolymer / 10㎛Ethylene-propylene random copolymer / 30㎛ / 15 wt%Crosslinked homo polypropylene / 30㎛ / 50%Ethylene-propylene random copolymer / 10㎛Comparative example 4Ethylene-propylene random copolymer / 10㎛Ethylene-propylene random copolymer / 30㎛ / 15 wt%Crosslinked homo polypropylene / 30㎛ / 85%Ethylene-propylene random copolymer / 10㎛Comparative example 5Ethylene-propylene random copolymer / 10㎛Polypropylene homo copolymer / 30㎛Crosslinked homo polypropylene30㎛ / 60%Ethylene-propylene random Copolymer / 10㎛ Experimental Example 1: Evaluation of sealing properties of pouch-type battery case Each of the pouch film laminates manufactured in Examples 1 to 3 and Comparative Examples 1 to 5 was cut to a width of 266 mm and a length of 200 mm, folded in half to a size of 133 mm × 200 mm so that the sealant layers were in contact, and then the long side (200 mm) was sealed for 1.6 seconds, 3 seconds, or 5 seconds, respectively, under the conditions of a seal bar area of ​​200 mm × 8 mm, 200°C, and 0.1 MPa, thereby manufacturing a pouch-type battery case in which a sealing portion was formed, and the sealing strength of the pouch-type battery case according to each sealing time was measured. Specifically, the sealing strength was calculated from the maximum value of the tensile strength measured by cutting the sealing portion formed on the pouch-shaped battery case at 15 mm intervals and pulling it in the 180° direction at a speed of 5 mm / min at room temperature using a UTM. Based on the produced sealing strength, the sealing of the pouch film laminates manufactured in Examples 1 to 3 and Comparative Examples 1 to 5 is shown in Table 2 below. -O: When the measured sealing strength is 10 kgf or more -X: If the measured sealing strength is less than 10 kgf Whether to seal when the sealing time is 1.6 seconds Whether to seal when 3 seconds Whether to seal when 5 seconds Example 1OOO Example 2OOO Example 3OOO Comparative Example 1XOO Comparative Example 2OOO Comparative Example 3OOO Comparative Example 4XOO Comparative Example 5XXO Referring to Table 2 above, it can be confirmed that the sealing strength is 10 kgf or more, indicating excellent sealing properties, even when the pouch-shaped battery case manufactured using the pouch film laminates manufactured in Examples 1 to 3 is sealed for 1.6 seconds. On the other hand, in the case of the pouch-shaped battery case manufactured using the pouch film laminates manufactured in Comparative Examples 1, 4, and 5, the sealing strength is insufficient when sealed for 1.6 seconds, and it can be confirmed that the sealing properties can be secured when the sealing time is 3 seconds or more. In particular, in the case of the pouch-shaped battery case manufactured using the pouch film laminate manufactured in Comparative Example 5, it can be seen that the time required to secure sufficient sealing properties increases to 5 seconds or more. Through this, it can be understood that the sealing time can be significantly shortened when the pouch film laminates manufactured in Examples 1 to 3 are used compared to when the pouch film laminates manufactured in Comparative Examples 1, 4, and 5 are used. Experimental Example 2: Evaluation of insulation resistance of pouch-type battery case The pouch film laminates manufactured in Examples 1 to 3 and Comparative Examples 1 to 5 were cut to 266 mm in width and 200 mm in length, respectively, and then folded in half to a size of 133 mm in width × 200 mm so that the sealant layers were in contact, and then the long side (200 mm) was sealed for 3 seconds under conditions of a seal bar area of ​​200 mm × 8 mm, 200°C, and 0.1 MPa, thereby manufacturing a pouch-type battery case with a sealing portion formed therein. The insulation resistance of the pouch-type battery case manufactured above was measured. Specifically, the insulation resistance was measured by checking the resistance value 5 seconds after applying 100 V using Resistance Meter (RM3544-01) of HIOKI. The measurement results are shown in Table 3 below. Insulation resistance [MΩ] Example 11676 Example 21598 Example 31507 Comparative Example 11520 Comparative Example 2175 Comparative Example 3603 Comparative Example 4279 Comparative Example 51666 Referring to Table 3 above, it can be confirmed that the pouch-type battery cases manufactured using the pouch film laminates manufactured in Examples 1 to 3 have better insulation resistance than the pouch-type battery cases manufactured using the pouch film laminates manufactured in Comparative Examples 1 to 5. In particular, in the case of the pouch-type battery cases manufactured using the pouch film laminates manufactured in Examples 1 to 3 in which the crosslinking degree of the crosslinked polypropylene film satisfies 52% to 80%, it can be confirmed that the insulation resistance is significantly better than the pouch-type battery cases manufactured using the pouch film laminates manufactured in Comparative Examples 2, 3, and 4 which do not satisfy the crosslinking degree. In addition, in the case of the pouch-type battery cases manufactured using the pouch film laminate manufactured in Example 1, it can be confirmed that the insulation resistance is better than the pouch-type battery cases manufactured using the pouch film laminates manufactured in Examples 2 and 3 in which the thicknesses of the first sealant layer and the second sealant layer were controlled. (Explanation of symbols) 100: Pouch film laminate 110: Base layer 112: 1st floor 114: Second layer 120: Gas barrier layer 130: Sealant layer 132: 1st sealant layer 134: Second sealant layer 136: Third sealant layer 138: 4th sealant layer 200: Pouch-type secondary battery 210: Pouch-type case 220: Case 1 222: Cup part 224: Reception area 230: Case 2 232: Cup part 240: Bridge section 250: Sealing part 260: Electrode assembly 270: Electrode tab 272: Bipolar tab 274: Negative tab 280: Electrode Lead 282: Bipolar Lead 284: Negative lead 290: Insulation

Claims

1. A pouch film laminate in which a substrate layer; a gas barrier layer; and a sealant layer are laminated in that order, The sealant layer comprises a first sealant layer comprising a polypropylene random copolymer and a second sealant layer comprising crosslinked polypropylene, The above cross-linked polypropylene is a pouch film laminate having a cross-linking degree of 52% to 80%.

2. In paragraph 1, A pouch film laminate, wherein the first sealant layer comprises at least one selected from the group consisting of an ethylene-propylene random copolymer and a butene-propylene random copolymer.

3. In paragraph 1, A pouch film laminate, wherein the second sealant layer comprises cross-linked homopolypropylene.

4. In paragraph 1, A pouch film laminate, wherein the ethylene monomer of the polypropylene random copolymer is contained in an amount of 5 to 50 wt% based on the total weight of the first sealant layer.

5. In paragraph 1, A pouch film laminate, wherein the ratio (A / B) of the thickness (A) of the first sealant layer and the thickness (B) of the second sealant layer is 0.6 to 1.

5.

6. In paragraph 1, A pouch film laminate having a thickness of the sealant layer of 30 ㎛ to 130 ㎛.

7. In paragraph 1, A pouch film laminate, wherein the insulation resistance of the pouch film laminate is 1000 MΩ or more when sealed at 200℃ and 0.1 MPa for 3 seconds.

8. In paragraph 1, A pouch film laminate having a melting temperature of the sealant layer of 120°C to 150°C.

9. In paragraph 1, The total thickness (D) of the above two pouch film laminates before sealing A ) and two sheets of the above pouch film laminate were sealed at 200°C and 0.1 MPa for 3 seconds, and the total thickness (D) of the two sheets of the above pouch film laminate S ) of the ratio (D) S / D A ) is 0.2 to 0.6, pouch film laminate.

10. In paragraph 1, The above sealant layer further includes a third sealant layer at the outermost layer, A pouch film laminate, wherein the third sealant layer comprises a polypropylene random copolymer.

11. In paragraph 10, A pouch film laminate, wherein the sealant layer is formed by sequentially laminating a first sealant layer, a second sealant layer, and a third sealant layer.

12. A pouch-shaped battery case manufactured by molding a pouch film laminate according to any one of claims 1 to 11.

13. A pouch-shaped battery case manufactured by molding a pouch film laminate according to any one of claims 1 to 11; and A pouch-type secondary battery including an electrode assembly housed in the above pouch-type battery case.

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