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

Abstract

The present invention relates to a pouch film laminate comprising a base layer, a gas barrier layer, and a sealant layer which are sequentially laminated, wherein the sealant layer has a value of fT of 0.32-3.1, represented by [equation 1], and a surface roughness (Ra) of the sealant layer is 0.11-0.75 μm. [Equation 1] fT = fT2 / fT1. In [equation 1], fT1 is a friction coefficient of the sealant layer at T1, fT2 is a friction coefficient of the sealant layer at T2, and T1 and T2 are different temperatures.

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 from Korean Patent Application No. 10-2023-0120750, dated September 11, 2023, the entire contents of which are incorporated herein by reference. Technology field The present invention relates to a pouch film laminate, a pouch-shaped battery case, and a pouch-shaped secondary battery. More specifically, the present invention relates to a pouch film laminate, a pouch-shaped battery case, and a pouch-shaped secondary battery, which have improved formability by having a coefficient of friction within a certain range regardless of temperature. Secondary batteries are used not only in small products such as digital cameras, P-DVDs, MP3 players, mobile phones, PDAs, portable game devices, power tools, and e-bikes, but also in large products requiring high output such as electric vehicles and hybrid vehicles, as well as in power storage devices that store surplus generated power or renewable energy and power storage devices for backup purposes. Typically, secondary batteries are 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, then housing the electrode assembly in a battery case, injecting electrolyte, and sealing it. Secondary batteries are classified into pouch type and can type, depending on the material of the case housing the electrode assembly. Pouch type batteries house the electrode assembly in a pouch made of a flexible polymer material. Can type batteries house the electrode assembly in a case made of materials such as metal or plastic. A pouch-type battery case is manufactured by forming a cup portion by performing press processing on a flexible pouch film laminate. Then, once the cup portion is formed, an electrode assembly is accommodated in the cup portion's receiving space and a sealing portion is sealed to manufacture a secondary battery. Among these press processes, drawing forming is performed by inserting a pouch film into a press device and applying pressure to the pouch film laminate with a punch to stretch the pouch film laminate. The pouch film laminate is generally formed of multiple layers, each of which has a polymer film, such as polyethylene terephthalate, laminated on one side of a metal gas barrier layer and a sealant layer laminated on the other side. With the recent rise in demand for high-capacity batteries, such as those for electric vehicles and energy storage systems (ESS), there is a growing need for battery cases capable of accommodating more electrode assemblies. Accordingly, attempts are being made to increase the depth of the cup molding in pouch-type battery cases, or to create a two-cup molding method that increases the volume of the cups by molding them separately in the upper and lower cases. In the conventional manufacturing of pouch film laminates, a slip agent is incorporated into the innermost sealant layer of the pouch film to prevent adhesion between the pouch films and facilitate post-processing, or a slip agent is applied to the surface of the sealant layer. However, at high temperatures, the slip agent penetrates into the sealant layer, causing it to disappear. Therefore, there is a need for the development of a pouch film laminate that prevents adhesion between pouch film laminates regardless of temperature, facilitates post-processing, and does not cause cracks even when the cup forming depth is increased. The present invention is intended to solve the above problems, and provides a pouch film laminate, a pouch-type battery case, and a pouch-type secondary battery having excellent formability by preventing adhesion between pouch film laminates regardless of temperature and having no significant change in coefficient of friction depending on temperature. 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 includes a sequentially laminated substrate layer, a gas barrier layer, and a sealant layer, wherein the sealant layer is represented by the following [Formula 1] f T A pouch film laminate is provided, wherein the value of is 0.32 to 3.1, and the surface roughness (Ra) of the sealant layer is 0.11 ㎛ to 0.75 ㎛. [Formula 1] f T = f T2 / f T1 In the above [Formula 1], f T1 is the friction coefficient of the sealant layer at T1, and f T2 is the friction coefficient of the sealant layer at T2, where T1 and T2 are different temperatures. [2] The present invention, in the above [1], the f T The value can be between 0.33 and 3.0. [3] In the present invention, in the above [1] or [2], T1 may be 25°C, and T2 may be any temperature between 0°C and 125°C, excluding 25°C. [4] In at least one of the above [1] to [3], the T1 may be 25°C and the T2 may be 60°C. [5] In at least one of the above [1] to [4], the surface roughness (Ra) of the sealant layer may be 0.16 µm to 0.55 µm. [6] In at least one of the above [1] to [5], the sealant layer may include a raised protrusion. [7] In at least one of the above [1] to [6], the coefficient of friction of the sealant layer at 60°C may be 0.38 or less. [8] The present invention, in at least one of the above [1] to [7], the pouch film laminate is represented by the following [Formula 2] D T The value can be between 0.82 and 1.22. [Formula 2] D T = D T2,a / D T1,a In the above [Formula 2], D T1,a is the forming depth at which cracks occur when the pouch film laminate is cut to a size of 300 mm x 400 mm at T1,a and then formed to have two cup parts with a size of 90 mm wide x 160 mm long, and D T2,a is the forming depth at which cracks occur when a pouch film laminate is cut to a size of 300 mm x 400 mm at T2,a and then formed to have two cup parts each measuring 90 mm wide x 160 mm long, and T1,a and T2,a are different temperatures. [9] In at least one of the above [1] to [8], the substrate layer may have a laminated structure of a polyethylene terephthalate film and a nylon film.

[0010] In at least one of the above [1] to [9], the thickness of the gas barrier layer may be 20 µm to 100 µm.

[0011] In at least one of the above [1] to

[0010] , the thickness of the sealant layer may be 30 µm to 130 µm.

[0012] The present invention provides a pouch-shaped battery case manufactured by drawing and molding the pouch film laminate of the above [1].

[0013] The present invention provides a pouch-type secondary battery including the battery case of

[0012] . The sealant layer included in the pouch film laminate according to the present invention has a friction coefficient within a certain range regardless of temperature, and also has a surface roughness (Ra) within a certain range, so that even when the lubricant on the surface of the sealant layer penetrates into the sealant layer at a high temperature, the blocking phenomenon in which the pouch film laminates stick to each other is prevented, and at the same time, excellent formability is achieved. In addition, when the pouch film laminate of the present invention is used, the molding defect rate according to the storage temperature and aging period of the pouch film laminate is reduced, and the pouch film laminate can be shipped without aging after production, and temperature control is unnecessary, thereby improving the processability. 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. Figure 1 is a cross-sectional view of a pouch film laminate according to one embodiment of the present invention. Figure 2 is an exploded assembly diagram of a secondary battery according to an embodiment of the present invention. Figure 3 is a drawing showing that no pouch breakage occurs when a pouch film laminate manufactured according to Example 1 is stored at 60°C and the pouch is formed. Figure 4 is a drawing showing pouch breakage that occurs when a pouch film laminate manufactured according to Comparative Example 3 is stored at 60°C and then formed into a pouch. Hereinafter, the present invention will be described in more detail. 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. In the present invention, the MD direction (Machine Direction) means the longitudinal direction of the pouch film laminate, and the TD direction (Transverse Direction) means the width direction of the pouch film laminate. In the present invention, the surface roughness (Ra) was measured using an optical measuring instrument (NV-2700, Optical Profiler, Nano System), and the lens used was Lens i20X, FOV 1.0X (FOV ~ 316㎛ ⅹ 237㎛), and the measurement was performed using WSI envelope mode. Specifically, the Sacn range was 10㎛ up / down, and the surface roughness was measured for 7 points in each 2D topo image (316㎛ ⅹ 237㎛) measured at an arbitrary point on the sample, and the average and standard deviation were calculated for the values ​​of 5 points excluding the maximum and minimum values. The inventors of the present invention have conducted repeated research to solve the problems that occur when the sealant penetrates into the sealant layer at high temperatures and the problems that occur during the process of manufacturing and storing a pouch film laminate through a roll-to-roll process. As a result, they have found that when the ratio of the coefficient of friction of the sealant layer in the pouch film laminate at different temperatures is controlled within a certain range while also controlling the surface roughness of the sealant layer within a certain range, excellent formability can be achieved regardless of the temperature, thereby completing the present invention. Hereinafter, the present invention will be described in detail. The pouch film laminate, pouch-type battery case and pouch-type secondary battery according to the present invention include at least one of the configurations disclosed below, and may include any combination between technically possible configurations among the configurations below. Pouch film laminate FIG. 1 illustrates one embodiment of a pouch film laminate according to the present invention. Hereinafter, the pouch film laminate according to the present invention will be described with reference to FIG. 1. Referring to FIG. 1, a pouch film laminate (1) according to the present invention includes a sequentially laminated substrate layer (10), a gas barrier layer (20), and a sealant layer (30), wherein the sealant layer (30) is represented by the following [Formula 1] f T The value is 0.32 to 3.1, and the surface roughness (Ra) of the sealant layer (30) is 0.11 ㎛ to 0.75 ㎛. [Formula 1] f T = f T2 / f T1 In the above [Formula 1], f T1 is the friction coefficient of the sealant layer at T1, and f T2 is the friction coefficient of the sealant layer at T2, where T1 and T2 are different temperatures. In the conventional manufacturing of pouch film laminates, in order to prevent adhesion between pouch films and facilitate post-processing, a slip agent is included in the sealant layer of the innermost layer of the pouch film, or a slip agent is applied to the surface of the sealant layer to control the coefficient of friction. However, at high temperatures, the slip agent penetrates into the sealant layer, disappears, and this causes a rapid increase in the coefficient of friction of the sealant layer. When the coefficient of friction increases in this way, cracks occur in the pouch during cup molding of the pouch-type battery case, which causes a problem in that the cup molding depth cannot be increased. In addition, when the slip agent disappears, there is a problem in that a blocking phenomenon occurs in which pouch film laminates stick to each other during the storage process. Accordingly, the inventors of the present invention have repeatedly developed a pouch film laminate that prevents adhesion between pouch film laminates even at high temperatures, facilitates post-processing, and does not cause cracks even when the cup forming depth is increased. As a result, they have found that when the friction coefficient of the sealant layer is controlled within a certain range at different temperatures and the surface roughness of the sealant layer is controlled within a certain range, excellent formability can be achieved regardless of the temperature, and more specifically, excellent formability can be achieved even at high temperatures. f expressed by the above [Formula 1] T The value of can specifically represent a value of 0.32 or more, 0.322 or more, 0.324 or more, 0.326 or more, 0.328 or more, or 0.33 or more, and can represent a value of 3.1 or less, 3.09 or less, 3.08 or less, 3.07 or less, 3.06 or less, 3.05 or less, 3.04 or less, 3.03 or less, 3.02 or less, 3.01 or less, or 3.0 or less. In addition, in the above [Formula 1], T1 and T2 are different temperatures. Preferably, T1 is 25°C, and T2 may be any temperature between 0°C and 125°C except 25°C, more preferably, T1 is 25°C, and T2 may be any temperature between 40°C and 125°C, even more preferably, T1 is 25°C, and T2 may be any temperature between 50°C and 125°C, and even more preferably, T1 is 25°C, and T2 may be 60°C. above f T If the value is less than 0.32 or more than 3.1, the friction coefficient of the sealant layer is greatly different at different temperatures, which causes a problem in that the formability deteriorates depending on the temperature, and a blocking phenomenon occurs in which the pouch film laminates stick to each other, which causes a problem in the processability. Therefore, the above f T When the value satisfies the above range, the coefficient of friction of the sealant layer can be appropriately controlled at different temperatures, so that the formability can be excellent regardless of the temperature, and there is no need to control the temperature, so that it can be excellent in terms of processability. Preferably, the sealant layer (30) is represented by f as shown in [Formula 1-1] below. 60,25 The value may be between 1.00 and 3.15, specifically between 1.5 and 3.1, more specifically between 1.80 and 3.05, and more specifically between 2.0 and 3.0. [Formula 1-1] f 60,25 = f 60℃ / f 25℃ In the above [Formula 1-1], f 60℃ is the friction coefficient of the sealant layer at 60℃, and f 25℃ is the coefficient of friction of the sealant layer at 25℃. above f TIt can be controlled in various ways, such as controlling the amount of the active agent included in the sealant layer, the melting point of the active agent, the mixing ratio of the active agent, or the surface roughness (Ra) of the sealant layer, but preferably, by controlling the surface roughness (Ra) of the sealant layer, the f T The value can be adjusted to an appropriate range. In addition, the surface roughness (Ra) of the sealant layer (30) is 0.11 µm to 0.75 µm. Preferably, it may be 0.12 µm to 0.72 µm, more preferably, it may be 0.13 µm to 0.70 µm, even more preferably, it may be 0.14 µm to 0.65 µm, even more preferably, it may be 0.15 µm to 0.60 µm, and even more preferably, it may be 0.16 µm to 0.55 µm. When a roll-to-roll process is applied for mass and high-speed production of pouch film laminates, after production of the pouch film laminate and prior to forming a pouch-shaped case, the pouch film laminate is stored in a roll shape in which a long rectangular parallelepiped is wound in one direction. In this case, the sealant layer (30) located at the lowest portion of the pouch film laminate is in a roll shape in contact with the substrate layer (10) due to the wound shape. At this time, when the surface roughness (Ra) of the sealant layer (30) is less than 0.11㎛, the contact area with the substrate layer increases due to the low surface roughness, and as a result, the lubricant on the surface of the sealant layer (30) is transferred to the substrate layer surface, so that the lubricant on the surface of the sealant layer (30) is further reduced. In addition, when stored at high temperatures as well as at room temperature, the solubility of the lubricant on the surface of the sealant layer (30) increases, so that a larger amount of the lubricant is transferred to the substrate layer surface, and thus, there is a disadvantage that the coefficient of friction may increase at room temperature, and the change in the coefficient of friction is large depending on the temperature, so that the fluctuation of the coefficient of friction increases depending on the temperature change. In this case, the maximum forming depth may decrease depending on the temperature change, and there is a disadvantage that the maximum forming depth decreases depending on the storage and / or transport method of the pouch film laminate. In addition, when the surface roughness (Ra) of the sealant layer (30) exceeds 0.75㎛, the contact area with the substrate layer decreases due to the high surface roughness, and as a result, the amount of the lubricant on the surface of the sealant layer (30) transferred to the surface of the substrate layer (10) decreases. Meanwhile, when forming a pouch-shaped case, the sealant layer (30) comes into contact with one end of the jig, and the substrate layer (10) comes into contact with the opposite end. However, as described above, the amount of the lubricant transferred to the surface of the substrate layer (10) decreases, so the coefficient of friction of the substrate layer (10) increases, and thus there is a problem in that the maximum forming depth decreases. In addition, when the surface roughness is excessively high, the coefficient of friction increases due to the anchor effect, which causes a problem in that the formability deteriorates. In this case, the maximum forming depth may decrease depending on temperature changes, and there is a disadvantage in that the maximum forming depth decreases depending on the storage and / or transport method of the pouch film laminate. Therefore, when the above range is satisfied, the phenomenon of sticking that occurs when two surfaces are bonded and instantaneously create joint points and repeatedly break the joint points during sliding does not occur, so an appropriate coefficient of friction can be maintained, thereby achieving excellent formability, and the degree of unevenness is not excessive, so that the formability does not decrease regardless of the temperature, and when a roll-to-roll process is performed, the amount of lubricant present on the surface of the sealant layer (30) and the substrate layer (10) can be appropriately controlled to realize excellent formability, while also having excellent insulation and sealing properties. The above sealant layer (30) may include either positive or negative protrusions, and is preferably a positive protrusion. In the case of a positive protrusion, particles with different average particle diameters can be added to the surface of the sealant layer to form a positive protrusion, thereby improving processability in that the surface roughness can be easily controlled. The above sealant layer (30) may have a friction coefficient of 0.20 or less at 25°C, preferably 0.01 to 0.15, more preferably 0.01 to 0.13, even more preferably 0.01 to 0.12, and even more preferably 0.02 to 0.11. When the above range is satisfied, the friction coefficient of the sealant layer is sufficiently low even at room temperature, so that formability can be excellent, and the blocking phenomenon in which pouch film laminates stick to each other can be prevented, while the friction coefficient of the sealant layer according to temperature change is not large, so that formability and processability can be excellent. The above sealant layer (30) may have a friction coefficient of 0.38 or less at 60°C, preferably 0.01 to 0.35, more preferably 0.05 to 0.33, and even more preferably 0.05 to 0.30. When the above range is satisfied, the friction coefficient of the sealant layer is sufficiently low even at high temperatures, so that formability can be excellent, and the blocking phenomenon in which pouch film laminates stick to each other can be prevented, while the friction coefficient of the sealant layer according to temperature change is not large, so that formability and processability can be excellent. The sealant layer (30) may include a lubricant. The lubricant may be any material capable of imparting slipperiness, and is not particularly limited thereto. For example, it may be erucamide. Including the lubricant can prevent whitening in the sealant layer and contamination occurring during the molding process. The sealant layer (30) may not include a lubricant layer applied with a lubricant. Conventionally, a process of applying a lubricant may be added to increase formability or maintain slipperiness. However, the sealant layer according to the present invention can exhibit excellent slipperiness and formability even without the lubricant layer, and thus may not include a lubricant layer. Accordingly, the processability can be improved by eliminating the additional process of applying a lubricant, and contamination occurring during the forming process can be prevented. Meanwhile, the above pouch film laminate is represented by the following [Formula 2] D T The value may be 0.82 to 1.22, preferably 0.85 to 1.2, more preferably 0.9 to 1.1, and even more preferably 0.94 to 1.06. [Formula 2] D T = D T2,a / D T1,a In the above [Formula 2], D T1,ais the forming depth at which cracks occur when the pouch film laminate is cut to a size of 300 mm x 400 mm at T1,a and then formed to have two cup parts with a size of 90 mm wide x 160 mm long, and D T2,a is the forming depth at which cracks occur when a pouch film laminate is cut to a size of 300 mm x 400 mm at T2,a and then formed to have two cup parts each measuring 90 mm wide x 160 mm long, and T1,a and T2,a are different temperatures. At this time, the T1,a may be 25°C, and the T2,a may be any temperature between 0°C and 125°C except 25°C, more preferably, the T1,a may be 25°C, and the T2,a may be any temperature between 40°C and 125°C, even more preferably, the T1,a may be 25°C, and the T2,a may be any temperature between 50°C and 125°C, and even more preferably, the T1,a may be 25°C, and the T2,a may be 60°C. Hereinafter, each layer of the pouch film laminate according to the present invention will be described in detail. (base layer) The substrate layer (10) is placed on the outermost layer of the battery case to protect the electrode assembly from external impact and electrically insulate it. According to one embodiment, the substrate layer (10) may have a laminated structure of a polyethylene terephthalate (PET) film and a nylon film. In this case, it is preferable that the nylon film is disposed on the gas barrier layer (20) side, i.e., on the inside, and the polyethylene terephthalate film is disposed on the surface side of the battery case. 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 with the aluminum alloy thin film constituting the gas barrier layer (20) is weak, and the stretching behavior is also different. Therefore, when the PET film is placed on the gas barrier layer side, the substrate layer and the gas barrier layer may be peeled off during the forming process, and the gas barrier layer 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 gas barrier layer (20), when a nylon film is placed between the polyethylene terephthalate and the gas barrier layer, an effect of improving 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 20 µm to 40 µm, preferably 20 µm to 35 µm, and more preferably 25 µm to 35 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. (gas barrier layer) The gas barrier layer (20) is laminated between the substrate layer (10) and the sealant layer (30) 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 (20) may be formed of a metal. For example, the gas barrier layer may be a metal thin film including one or more metals 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 (20) may be formed of an aluminum alloy thin film. When the gas barrier layer (20) 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 ensuring complementary electrochemical properties and heat dissipation properties due to the electrode assembly and 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 (20) may be formed of a stainless steel thin film. Specifically, the gas barrier layer (20) may be manufactured by molding and / or processing a stainless steel thin film. The gas barrier layer (20) 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, one selected from the group consisting of copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), silicon (Si), and zinc (Zn). The thickness of the above gas barrier layer (20) may be 20 µm to 100 µm, preferably 30 µm to 90 µm, and more preferably 40 µm to 85 µm. Since the present invention does not cause the problem of the substrate layer being deformed even when the sealing temperature is increased so that heat can be transferred to the sealant layer, 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. (Sealant layer) The sealant layer (30) 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. To this end, the sealant layer (30) may be formed of a material having excellent thermal bonding strength. The sealant layer (30) may be formed of a material having insulating, corrosion-resistant, and sealing properties. Specifically, since the sealant layer (30) is in direct contact with the electrode assembly and / or electrolyte inside the pouch-shaped battery case, it may be formed of a material having insulating and corrosion-resistant properties. In addition, since the sealant layer (30) must completely seal the inside of the pouch-shaped battery case to block material movement between the inside and the outside, it may be formed of a material having high sealing properties (e.g., excellent thermal bonding strength). In order to secure such insulating, corrosion-resistant, and sealing properties, the sealant layer (30) may be formed of a polymer material. The sealant layer (30) 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, polyparaphenylenebenzobisoxazole, polyarylate, and Teflon, and preferably may be made of a polyolefin resin such as polypropylene (PP) and / or polyethylene (PE). In this case, the polypropylene may be composed of cast polypropylene (CPP), acid modified polypropylene (Acid Modified Polypropylene, PPa), polypropylene-ethylene copolymer, and / or polypropylene-butylene-ethylene terpolymer. The thickness of the sealant layer (30) may be 30 µm to 130 µm, preferably 40 µm to 120 µm, and more preferably 60 µm to 100 µm. 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 (30) according to the present invention may have a composite film structure in which two or more materials are each formed to form layers. For example, the sealant layer (30) may have a multilayer structure. An adhesive layer and / or a skin layer may be disposed between each layer of the sealant layer (30) having a 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 (30). 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 disposed between the sealant layer (30) and the gas barrier layer (20). The pouch film laminate of the present invention as described above can be manufactured through a manufacturing method of 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 (10) to the upper surface of a gas barrier layer (20) using an adhesive, and forming a sealant layer (30) on the lower surface of the gas barrier layer (20) through co-extrusion or an adhesive layer, and can be manufactured through a method such as dry lamination or sandwich lamination. However, the manufacturing method of the pouch film laminate is not limited thereto. The pouch film laminate according to the present invention may have a total thickness of 120 µm to 300 µm, specifically 130 µm to 280 µm, and more preferably 140 µm to 250 µm. When the thickness of the pouch film laminate satisfies the above range, the forming depth can be increased while minimizing a decrease in battery accommodation space and a decrease in sealing durability due to an increase in the thickness of the pouch laminate. pouch-type secondary battery Next, a pouch-type secondary battery according to the present invention will be described. Figure 2 is an exploded assembly drawing of a pouch-type secondary battery (200) according to the present invention. As illustrated in FIG. 2, 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. 2. (Pouch-type battery case) 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 house an electrode assembly (260) inside. 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. The pouch film laminate can 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) can include a cup portion (222) and a receiving portion (224). The receiving portion (224) is a place for receiving an electrode assembly, and can mean a receiving space formed in the shape of a pocket on the inside of the cup portion (222) as the cup portion (222) is formed. According to one embodiment of the present invention, a 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 and separated from each other. According to another embodiment of the present invention, when forming a cup portion on a pouch film laminate, two symmetrical cup portions (222, 232) can be drawn and formed adjacent to each other on one pouch film laminate. In this case, cup portions (222, 232) can be formed in the first case (220) and the second case (230) respectively, 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 portions (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 portion (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 portion of the electrode lead (280) described later, i.e., a terminal portion, is exposed. Specifically, when the electrode lead (280) is connected to the electrode tab (270) of the electrode assembly (260) and an insulating portion (290) is formed on a portion of the electrode lead (280), the electrode assembly (260) can be housed in a receiving portion (224) provided in a cup portion (222) of the first case (220), and the second case (230) can cover the receiving portion (224) from above. Subsequently, an electrolyte can be injected into the interior of the receiving portion (224), and the sealing portions (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 at which the sealing portion (250) is sealed 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 through thermal bonding. (electrode assembly) The electrode assembly (260) can be inserted into a pouch-type battery case (210) and sealed by the pouch-type 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 is typically formed by stirring granular active materials, auxiliary conductors, binders, and conductive agents with the addition of a solvent. The solvent can be removed in a subsequent process. A slurry containing an electrode active material, 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 these are laminated on both sides of a separator, thereby manufacturing an electrode assembly (260) in a predetermined shape. The types of 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 outward from the electrode assembly (260) to serve as a path for electrons to 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. 2, the electrode tabs (270) may protrude in different directions of the electrode assembly (260), but are not limited thereto, and may be formed to protrude in various directions, such as protruding in parallel in the same direction from one side. (electrode leads) 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 serve as a terminal portion and be electrically connected to an external terminal. (insulating part) 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) may be formed of a non-conductive material that does not conduct electricity well. In general, the insulating portion (290) is often formed 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) may be used. The insulating portion (290) may be arranged to surround the outer circumference 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 thermally fused, and may adhere the electrode lead (280) to the battery case (210). (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. Hereinafter, the present invention will be described in more detail through specific examples. However, the following examples are merely illustrative and serve to aid understanding of the present invention and do not limit its scope. It will be apparent to those skilled in the art that various modifications and variations are possible within the scope and technical spirit of this disclosure, and such modifications and variations are naturally within the scope of the appended claims. Examples and Comparative Examples Example 1: Preparation of pouch film laminate To form surface roughness on the surface of a polypropylene (PP) film measuring 400 mm in width, 50 m in length, and 80 μm in thickness, a sealant layer was manufactured by adding polypropylene (PP) particles having a particle size of 10 μm. Thereafter, a second adhesive film, a 15 μm thick nylon film, a first adhesive film, and a 12 μm thick polyethylene terephthalate (PET) film were sequentially laminated on one side of an aluminum alloy film having a thickness of 40 μm, and the manufactured sealant layer was sequentially laminated on the other side of the aluminum alloy film. As a result, a pouch film laminate having a structure in which the manufactured sealant layer / aluminum alloy film / second adhesive film / nylon film / first adhesive film / polyethylene terephthalate film were sequentially laminated was manufactured. Example 2: Preparation of pouch film laminate A pouch film laminate was manufactured in the same manner as in Example 1, except that a sealant layer was manufactured by adding polypropylene (PP) particles having a particle size of 15 μm to the surface layer to form surface roughness. Example 3: Preparation of pouch film laminate A pouch film laminate was manufactured in the same manner as in Example 1, except that a sealant layer was manufactured by adding polypropylene (PP) particles having a particle size of 20 μm to the surface layer to form surface roughness. Example 4: Preparation of pouch film laminate A pouch film laminate was manufactured in the same manner as in Example 1, except that a sealant layer was manufactured by adding polypropylene (PP) particles having a particle size of 25 μm to the surface layer to form surface roughness. Comparative Example 1: Manufacturing of a pouch film laminate A pouch film laminate was manufactured in the same manner as in Example 1, except that a sealant layer was manufactured by adding Si particles having a particle size of 1 μm to the surface layer to form surface roughness. Comparative Example 2: Manufacturing of a pouch film laminate A pouch film laminate was manufactured in the same manner as in Example 1, except that a sealant layer was manufactured by adding Si particles having a particle size of 3 μm to the surface layer to form surface roughness. Comparative Example 3: Manufacturing of a pouch film laminate A pouch film laminate was manufactured in the same manner as in Example 1, except that a sealant layer was manufactured by adding Si particles having a particle size of 5 μm to the surface layer to form surface roughness. Comparative Example 4: Manufacturing of a pouch film laminate A pouch film laminate was manufactured in the same manner as in Example 1, except that a sealant layer was manufactured by adding Si particles having a particle size of 50 μm to the surface layer to form surface roughness. Experimental Example 1: Surface Roughness Measurement The surface roughness of the sealant layer in each pouch film laminate manufactured according to Examples 1 to 4 and Comparative Examples 1 to 4 was measured using an optical measuring device (NV-2700, Optical Profiler, Nano System). The measured surface roughness (Ra) is shown in [Table 1] below. Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Surface roughness (Ra, ㎛) 0.16 10.29 8 0.34 0 0.52 10.05 0 0.07 0 0.10 0 0.75 6 Experimental Example 2: Measurement of friction coefficient according to temperature Each pouch film laminate manufactured according to Examples 1 to 4 and Comparative Examples 1 to 4 was stored at 25°C and 60°C for 6 hours, respectively, and then the coefficient of friction was measured. As a method of measuring the coefficient of friction, a sled metal having a size of 130 mm (MD direction) x 65 mm (TD direction) and a weight of 200 g was brought into contact with a sealant layer of a pouch film laminate having a size of 500 mm (MD direction) x 400 mm (TD direction) and the measurement was made. In detail, the sled metal was moved 100 mm over the sealant layer at a speed of 100 mm / min, and the coefficient of friction was measured five times in the range of 20 mm to 80 mm, taking the average value. The friction coefficients measured for the pouch film laminates stored at 25°C and 60°C for 6 hours each are shown in [Table 2] below. Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Friction coefficient 25℃ 0.100.100.100.110.150.190.150.1260℃ 0.200.200.300.300.700.600.800.40f 60℃ / f 25℃ 2.02.03.02.74.73.25.33.3 As described in the above [Table 2], it can be seen that Comparative Examples 1 to 4, in which the surface roughness of the sealant layer was formed too low or too high, had a higher ratio of the coefficient of friction at 60°C to the coefficient of friction at 25°C than Examples 1 to 4. Experimental Example 3: Evaluation of the formability of pouch film laminates according to temperature. Each pouch film laminate manufactured according to Examples 1 to 4 and Comparative Examples 1 to 4 was stored at 25°C and 60°C for 6 hours, respectively, and then the formability of the pouch film laminate was evaluated. As a method for evaluating the formability of a pouch film laminate, the pouch film laminate was cut into equal sizes of 300 mm (MD direction) x 400 mm (TD direction), and then the forming depth was varied in a battery case forming device having two forming parts of 90 mm (MD direction) x 160 mm (TD direction) while recording the forming depth when a crack occurred. Here, the punch and the forming part of the battery case forming device were filleted at the corners and edges, and the corner of the punch had a curvature of 2 mm and the corner of the edge had a curvature of 0.5 mm, and the corner of the forming part had a curvature of 2.0 mm and the corner of the edge had a curvature of 1 mm. In addition, the clearance between the punch and the forming part was 0.5 mm. The measured forming depths for the pouch film laminates stored at 25°C and 60°C for 6 hours each are shown in [Table 3] below. Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 2 Cup part forming depth (mm) 25℃ 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 60℃ 8.0 7.5 8.0 8.0 6.0 6.0 6.5 6.5 D 60℃ / D 25℃ 1.00.941.01.00.750.750.810.81 As described in the above [Table 3], in the case of Examples 1 to 4, unlike Comparative Examples 1 to 4, there is no significant change in the cup part forming depth depending on the temperature, and it can be seen that excellent forming depth is exhibited even when using a pouch film laminate stored at a high temperature. [Explanation of symbols] 1: Pouch film laminate 10: Substrate layer 20: Gas barrier layer 30: Sealant layer 200: Pouch-type secondary battery 210: Pouch-type case 220: Case 1 222: Cup 224: Reception area 230: Case 2 232: Cup 240: Bridge section 250: Sealing part 260: Electrode assembly 270: Electrode tab 272: Positive tab 274: Negative tab 280: Electrode lead 282: Positive lead 284: Negative lead 290: Insulation

Claims

1. Contains a sequentially laminated substrate layer, a gas barrier layer, and a sealant layer, The above sealant layer is f expressed by the following [Formula 1] T The value is between 0.32 and 3.1, A pouch film laminate having a surface roughness (Ra) of the sealant layer of 0.11 ㎛ to 0.75 ㎛: [Formula 1] f T = f T2 / f T1 In the above [Formula 1], f T1 is the friction coefficient of the sealant layer at T1, and f T2 is the friction coefficient of the sealant layer at T2, where T1 and T2 are different temperatures.

2. In paragraph 1, above f T A pouch film laminate having a value of 0.33 to 3.

0.

3. In paragraph 1, A pouch film laminate wherein the above T1 is 25°C and the above T2 is any temperature between 0°C and 125°C, excluding 25°C.

4. In paragraph 1, A pouch film laminate wherein the above T1 is 25°C and the above T2 is 60°C.

5. In paragraph 1, A pouch film laminate having a surface roughness (Ra) of the sealant layer of 0.16 ㎛ to 0.55 ㎛.

6. In paragraph 1, The above sealant layer is a pouch film laminate including a raised protrusion.

7. In paragraph 1, A pouch film laminate having a coefficient of friction of the sealant layer at 60°C of 0.38 or less.

8. In paragraph 1, The above pouch film laminate is represented by the following [Formula 2] D T Pouch film laminates having a value of 0.82 to 1.22: [Formula 2] D T = D T2,a / D T1,a In the above [Formula 2], D T1,a is the forming depth at which cracks occur when the pouch film laminate is cut to a size of 300 mm x 400 mm at T1,a and then formed to have two cup parts with a size of 90 mm wide x 160 mm long, and D T2,a is the forming depth at which cracks occur when a pouch film laminate is cut to a size of 300 mm x 400 mm at T2,a and then formed to have two cup parts each measuring 90 mm wide x 160 mm long, and T1,a and T2,a are different temperatures.

9. In paragraph 1, A pouch film laminate in which the above-mentioned substrate layer is a laminated structure of a polyethylene terephthalate film and a nylon film.

10. In paragraph 1, A pouch film laminate having a thickness of the gas barrier layer of 20 µm to 100 µm.

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

12. A pouch-shaped battery case manufactured by drawing and molding the pouch film laminate of paragraph 1.

13. A pouch-type secondary battery including the battery case of Article 12.

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