Cell pouch film and method for storing the same

Abstract

This invention provides a cell pouch film with excellent moldability and reduced leakage of slip agents, as well as a method for storing the same film. [Solution] A cell pouch film comprising a sealant layer containing a slip agent; a metal layer formed on the sealant layer; and an outer layer formed on the metal layer, wherein the film is stored at a temperature of 48-57°C for 30 days, and then, using a lubricant testing device in which a cubic metal of 1.3 kgf is wrapped in a black pouch with a matte black appearance and an outer layer made of nylon, the surface of the black pouch is rubbed against the sealant layer or outer layer of the film at a speed of 400 mm / 10 s, and the surface roughness of the portion where the slip agent leaked out of the film seeped out and formed white stripes on the black pouch satisfies Rt 13-20 μm and Rz 10-15 μm.

Description

Technical Field

[0001] This specification relates to a film for a cell pouch and a method for storing the same.

[0002] Cross-references to related applications This application claims priority based on Korean Patent Application No. 10-2023-0066379, filed on May 23, 2023, and the entire contents of the said application are incorporated herein by reference. This application claims priority based on Korean Patent Application No. 10-2024-0061080, filed on May 9, 2024, and the entire contents of the said application are incorporated herein by reference.

[0003] Explanation of government-supported research and development This research was carried out through the following national projects. - Department name: Ministry of Trade, Industry and Energy, Project management (specialized) agency name: Korea Institute of Industrial Technology Evaluation and Management, Research project name: Material component package type (top company), Research project title: Development of next-generation secondary battery pouch capable of realizing high adhesion strength (60°C) more than twice, Project execution agency name: Kurumura Chemical Co., Ltd., Project number: 20022450, Project unique number: 1415185612

Background Art

[0004] Pouch-type batteries, commonly used in electric vehicles and other applications, have advantages over cylindrical and prismatic batteries, including ease of modification and high energy density. Cell pouches are outer materials that enclose the battery's electrode array and electrolyte. They must meet required characteristics such as interlayer adhesion, heat fusion strength, electrolyte resistance, airtightness, moisture permeability, and moldability, and are composed of a thin metal film and polymer. In particular, cell pouches need high moldability to be applied to large batteries such as those in electric vehicles (EVs) and energy storage systems (ESS). Therefore, cell pouches must contain a slip agent as an additive to improve moldability. The slip agent provides moldability by flowing out to the surface of the outermost layer of the pouch depending on the temperature and pressure after manufacturing. However, if an excessive amount of slip agent flows out, the slip agent particles aggregate and cause contamination on the process, drastically reducing process efficiency. Therefore, there is a need to develop cell pouch films that can prevent the aggregation of slip agent while providing high moldability. [Overview of the project] [Problems that the invention aims to solve]

[0005] The problem that this disclosure aims to solve is to provide a cell pouch film with excellent moldability and reduced slip agent leakage, as well as a method for storing the same. [Means for solving the problem]

[0006] One embodiment of the present disclosure is a sealant layer containing a slip agent; A metal layer formed on the sealant layer; and An outer layer formed on the aforementioned metal layer; A cell pouch film containing, The film provides a cell pouch film in which, after being stored at a temperature of 48-57°C for 30 days, a lubricant testing device is used in which a cubic metal of 1.3 kgf is wrapped in a black pouch having a matte black appearance and an outer layer made of nylon. When the front surface of the black pouch is rubbed against the sealant layer or outer layer of the film at a speed of 400 mm / 10 s, the surface roughness of the portion where the slippery agent leaked out of the film seeped out and formed white stripes on the black pouch satisfies Rt 13-20 μm and Rz 10-15 μm.

[0007] Another embodiment of the present disclosure provides a cell pouch including the cell pouch film.

[0008] Another embodiment of the present disclosure provides a method for storing a cell pouch film as described in one of the paragraphs, the method comprising the step of storing the film at a temperature of 48 to 57°C. [Effects of the Invention]

[0009] According to one embodiment of the present disclosure, by adjusting the storage temperature after manufacturing of the cell pouch film, it is possible to minimize the phenomenon of excessive slip agent flowing out to the surface, even while containing a small amount of slip agent, thereby improving the efficiency of the slip agent. Therefore, the film according to the present disclosure exhibits excellent moldability and prevents excessive slip agent flow, thus preventing process defects caused by the slip agent. [Brief explanation of the drawing]

[0010] [Figure 1] This shows the results of measuring the surface roughness of Examples 1 and 2, and Comparative Example 4 in Test Example 1. [Figure 2] This is an image of the lubricant testing device used in Test Example 2. [Figure 3] This is an image of the black pouch taken after the lubricant test in Test Example 2. [Figure 4] This diagram shows the evaluation criteria (S, A, B grades) for lubricant testing in Test Example 2. [Figure 5A] This image shows the size analysis results of particles formed by the aggregation of the slip agent in Example 1 (storage temperature 50°C) after the lubricant test in Test Example 2. (80x magnification image) [Figure 5B] This image shows the size analysis results of particles formed by the aggregation of the slip agent in Example 1 (storage temperature 50°C) after the lubricant test in Test Example 2. (450x magnification image) [Figure 6A] This image shows the size analysis results of particles formed by the aggregation of the slip agent in Comparative Example 4 (storage temperature 45°C) after the lubricant test in Test Example 2. (80x magnification image) [Figure 6B] This image shows the size analysis results of particles formed by the aggregation of the slip agent in Comparative Example 4 (storage temperature 45°C) after the lubricant test in Test Example 2. (450x magnification image) [Modes for carrying out the invention]

[0011] Preferred embodiments of this disclosure will be described in detail below with reference to the attached drawings.

[0012] The embodiments of the Disclosure disclosed herein are provided for illustrative purposes only, and the embodiments may be carried out in various forms and should not be construed as being limited to the embodiments described herein. The Disclosure may be modified in various ways and may take various forms, and the embodiments should be understood not as attempting to limit the Disclosure to any particular form of disclosure, but as including all modifications, equivalents, or substitutes that fall within the spirit and technical scope of the Disclosure.

[0013] A singular expression includes plural expressions unless the context clearly indicates otherwise. In this application, terms such as “includes” or “has” are intended to indicate the presence of features, figures, stages, operations, components, parts, or combinations thereof described in the specification, and do not preclude the presence or possibility of adding one or more other features, figures, stages, operations, components, parts, or combinations thereof.

[0014] As used herein, the term "cell" means a battery, and has the broadest meaning including all kinds of batteries such as secondary batteries like lithium ion batteries and lithium polymer batteries, and portable storage batteries.

[0015] As used herein, the term "cell pouch" means a structure in which cell components such as a positive electrode, a negative electrode, and a separator are impregnated and stored in an electrolytic solution, and in order to store the cell components, it has the broadest meaning including all those in which a film with a laminated structure considering gas barrier properties, flexibility, electrolytic solution resistance, heat adhesiveness, etc. is processed into a bag shape, a box shape, etc.

[0016] As used herein, the term "formability" means the property that when a film for a cell pouch is processed into a predetermined shape, it can be processed into the target shape without cracks or breaks and can maintain that shape. For example, the formability can be evaluated by measuring the maximum depth at which no cracks or breaks occur when forming a single cup shape by applying a pressure of 0.3 MPa to a specimen obtained by cutting a film for a cell pouch. More specifically, when none of the 10 identical film specimens are broken, a deeper depth can be applied, and when even one is broken, the depth immediately before that can be defined as the maximum height. For example, the evaluation of the formability may be performed using a rectangular parallelepiped-shaped forming cup (entrance size: 16 cm × 9 cm). More specifically, it may be evaluated using the GS-S5 model manufactured by GWANGSHIN HI-TECH.

[0017] One embodiment of the present disclosure is a film for a cell pouch including a sealant layer, a metal layer formed on the sealant layer, and an outer layer formed on the metal layer. The sealant layer contains a slip agent. After the film is stored at a temperature of 48 to 57°C for 30 days, when the front surface of the black pouch, in which a cubic metal of 1.3 kgf is wrapped with a black pouch whose appearance is black matte and the outer layer is made of nylon, is rubbed against the sealant layer or the outer layer of the film at a speed of 400 mm / 10 s using a lubricant inspection device, the surface roughness of the portion where the slip agent flowing out from the film forms white streaks on the black pouch satisfies Rt 13 to 20 μm and Rz 10 to 15 μm. A film for a cell pouch can be provided.

[0018] According to one embodiment of the present disclosure, the film may be for storage at a temperature of 48 to 57°C, and by adjusting the storage temperature, it is possible to prevent excessive outflow of the slip agent and aggregation of the slip agent. Specifically, the storage temperature may be 48°C or higher, 49°C or higher, 50°C or higher, 51°C or higher, 52°C or higher, 53°C or higher, or 54°C or higher, and may be 57°C or lower, 56°C or lower, 55°C or lower, 54°C or lower, 53°C or lower, 52°C or lower, or 51°C or lower. If the storage temperature exceeds 57°C, the formability may decrease. If it is less than 48°C, the slip agent may flow out excessively and aggregate, causing process defects and potentially reducing the product reliability.

[0019] In one embodiment, the storage period during storage may be 10 days to 300 days. Specifically, it may be 10 days or more, 20 days or more, 30 days or more, 40 days or more, 50 days or more, 60 days or more, 70 days or more, 80 days or more, 90 days or more, 100 days or more, 150 days or more, 200 days, or 250 days or more, and may be 300 days or less, 200 days or less, 100 days or less, 90 days or less, 80 days or less, 70 days or less, 60 days or less, 50 days or less, 40 days or less, 30 days or less, 20 days or less, or 10 days or less.

[0020] In one embodiment, the relative humidity during storage may be 5% to 25%. In this disclosure, "relative humidity (RH)" as used herein means the ratio of the amount of water vapor currently contained in the air to the saturation vapor pressure that a given volume of air can contain, expressed as a percentage (%).

[0021] In one embodiment, the surface roughness of the film is parameterized by the manner in which the slip agent contained in the sealant layer of the film flows out to the sealant layer and the outer layer, respectively, and partially aggregates. In this disclosure, surface roughness means the degree of fine irregularities present on the surface. Among the parameters of surface roughness, Rt is the maximum height roughness, and is measured as the vertical distance between two parallel lines that are parallel to the center line in the roughness curve within the cut-off length of the extracted portion and pass through the highest and lowest points of the curve. Rz is the ten-point median height, and is measured as the distance between the average height from the maximum peak height to the fifth average valley depth and the average valley depth from the maximum valley depth to the fifth average valley depth.

[0022] In one embodiment, the black pouch used for measuring the surface roughness is a pouch (manufacturer: Kurimura Chemical Co., Ltd.) that has a matte black appearance and an outer layer made of nylon. When the black pouch is rubbed, the slip agent that flows out from the film may seep onto the surface of the black pouch as the front surface of the black pouch rubs against the sealant layer or outer layer of the film, forming white stripes. This disclosure has found that when the film containing the slip agent in the sealant layer exhibits the aforementioned surface roughness range, a small amount of slip agent flows out, forming small aggregated particles while still exhibiting high moldability. From this viewpoint, when measured by the above method, the surface roughness of the portion where white stripes are formed may satisfy Rt 13-20 μm and Rz 10-15 μm. Here, the surface roughness may be the value obtained when the sealant layer is rubbed once or the outer layer is rubbed five times in the same direction. Specifically, the surface roughness Rt (μm) may be 13 or more, 14 or more, 15 or more, 16 or more, 17 or more, 18 or more, or 19 or more, and may also be 20 or less, 19 or less, 18 or less, 17 or less, 16 or less, 15 or less, or 14 or less. Also, the surface roughness Rz (μm) may be 10 or more, 11 or more, 12 or more, 13 or more, or 14 or more, and may also be 15 or less, 14 or less, 13 or less, 12 or less, or 11 or less. Films whose surface roughness Rt and Rz fall outside the above ranges may have excessive slippage of the slip agent during lubricant inspection, resulting in aggregated particles larger than 60 μm on the surface of the sealant layer, and the friction coefficient and moldability of the sealant layer may be shown to be low.

[0023] In one view, the film according to one embodiment may, after being stored at a temperature of 48-57°C for 30 days, be subjected to the same lubricant testing device described above, where the front surface of the black pouch of the lubricant testing device is rubbed against the sealant layer or outer layer of the film at a speed of 400 mm / 10 s. The average diameter of the largest aggregated particles of the slip agent present in the portion where the slip agent leaked out of the film and formed white stripes on the black pouch may be 60 μm or less. Here, the aggregated particles of the slip agent refer to particles formed by the aggregation of the leaked slip agent. The size of the particles increases as more slip agent leaks out. The largest aggregated particle refers to the largest aggregated particle among the formed aggregated particles, and the average diameter refers to the average value of the diameter measured for a single aggregated particle. Specifically, the largest aggregated particle among the aggregated particles of the slip agent may mean the largest aggregated particle among those that make up 100% or less, 98% or less, 96% or less, 94% or less, 92% or less, 90% or less, 88% or less, 86% or less, 84% or less, 82% or less, or 80% or less of the total aggregated particles of the slip agent. Or, specifically, the largest aggregated particle among the aggregated particles of the slip agent may mean the largest aggregated particle among the aggregated particles included in the image taken with a scanning electron microscope (SEM). Here, the size of the aggregated particles of the slip agent may be the value obtained when the sealant layer is rubbed once, or the outer layer is rubbed five times in the same direction. More specifically, the size of the aggregated particles of the slip agent may be 60 μm or less, 50 μm or less, or 40 μm or less. In one embodiment, the size of the aggregated particles can be confirmed from the microscope image.

[0024] From one perspective, the film according to one embodiment may have a moldability of 15 to 25 mm after storage at a temperature of 48 to 57°C for 30 days. Here, the moldability is measured by measuring the maximum depth at which tearing does not occur when molding one cup (16 cm x 9 cm) by applying a pressure of 0.3 MPa to the film. More specifically, the moldability may be 15 mm or more, 16 mm or more, 17 mm or more, 18 mm or more, 19 mm or more, 20 mm or more, 21 mm or more, 22 mm or more, or 23 mm or more, and may be 25 mm or less, 24 mm or less, 23 mm or less, 22 mm or less, 21 mm or less, or 20 mm or less.

[0025] In one view, when the friction coefficient of the film according to one embodiment is evaluated as follows after being stored at a temperature of 48 to 57°C for 30 days, the friction coefficient of the sealant layer according to one embodiment of the disclosure may be 0.15 to 0.5: (a) After manufacturing a cell pouch using the film according to one embodiment of the disclosure, a test piece is prepared by cutting it to a size of 200 mm × 100 mm, and the test piece is attached flat to the bottom of the friction coefficient measuring device. (b) Next, a test piece of the same cell pouch, measuring 70 mm × 60 mm, is fixed to the friction coefficient measuring jig. (c) Next, the jig provided in the friction coefficient measuring device is placed between the two pouches so as to contact both pouches, and then the bottom of the friction coefficient measuring device is moved at a speed of 15 mm / 1 s for 55 seconds to measure the friction coefficient between the sealant layers of the pouches. In one embodiment, the friction coefficient measuring device may be a Labsink CF-800XS model. Specifically, the coefficient of friction may be 0.15 or more, 0.2 or more, 0.25 or more, or 0.3 or more, and may also be 0.5 or less, 0.4 or less, 0.35 or less, 0.3 or less, 0.25 or less, or 0.2 or less.

[0026] In this disclosure, the material and thickness of each layer of the film are not particularly limited as long as they can be manufactured as a film for cell pouches, but may include, for example, the following configurations.

[0027] In this disclosure, the sealant layer refers to an inner layer that, after the cell is embedded, is bonded by heat to provide sealing properties. In one embodiment, the sealant layer may contain a heat-adhesive resin, i.e., a sealing resin for heat bonding. Specifically, the sealant layer may contain one or more selected from the group consisting of polyolefins such as polypropylene (PP) and polyethylene (PE), copolymers thereof, terpolymers or derivatives thereof, and ethylene vinyl acetate (EVA). The copolymer or terpolymer may include ethylene / propylene copolymer or ethylene / propylene / butadiene terpolymer. In one embodiment, the sealant layer may have a thickness of 20 μm to 100 μm. The sealant layer may consist of multiple layers.

[0028] In this disclosure, the slip agent means an additive that reduces the coefficient of friction on the surface of a film and provides lubricity and moldability. In one embodiment, the slip agent may include one or more of the following: wax-based, amide-based, siloxane, and silicone. Specifically, the slip agent may be an oleamide-based slip agent. More specifically, the slip agent may include one or more of the following: erucamide, behenamide, stearamide, and oleamide.

[0029] In one embodiment, the film may contain 0.1 to 20% by weight of a slip agent relative to the total weight of the sealant layer. Specifically, the film may contain 0.1% or more, 0.2% or more, 0.3% or more, 0.4% or more, 0.5% or more, 0.6% or more, 0.7% or more, 0.8% or more, 0.9% or more, 1% or more, 2% or more, 3% or more, 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, 12% or more, 15% or more, 17% or more, or 19% or more of a slip agent relative to the total weight of the sealant layer, and may also contain 20% or less, 17% or less, 15% or less, 13% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, or 0.5% or less of a slip agent relative to the total weight of the sealant layer. If the slip agent is added in excess of the aforementioned range, the sealing strength may decrease, resulting in poor winding and uneven physical properties over time. It may also cause problems with foreign matter during the manufacturing process, thus impairing the reliability of the product. Conversely, if the slip agent is added in a smaller amount than the aforementioned range, the moldability may decrease.

[0030] In this disclosure, the outer layer means a layer having heat resistance, wear resistance, chemical resistance, etc., for the purpose of protecting the metal layer. As an example, the outer layer may contain one selected from the group consisting of polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polyhydroxyaldehyde (PHA), polylactic acid (PLA), thermoplastic starch (TPS), polyvinyl alcohol (PVA), polycaprolactam (PCL), polyethylene (PE), polypropylene (PP), ethylene vinyl acetate (EVA), ethylene vinyl alcohol (EVOH), polyvinylidene chloride (PVDC), polyethylene terephthalate (PET), and nylon. More specifically, the outer layer may contain one or more resins selected from nylon resin, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc. In one example, the outer layer may have a thickness of 5 μm to 40 μm. The outer layer may be composed of multiple layers.

[0031] In this specification, the metal layer means a barrier layer having the ability to block water vapor or air from outside the battery, gases generated inside the battery, and / or moisture. In one embodiment, the metal layer may further include a surface treatment layer uniformly coated on one or both sides thereof. In one embodiment, the metal layer may be a thin metal film or a metal vapor-deposited layer. The thin metal film is a metal foil. The metal vapor-deposited layer may be formed by vacuum-depositing metal onto a separate plastic film, such as polyethylene terephthalate (PET), polyethylene (PE), or polypropylene (PP).

[0032] As one embodiment, the metal of the metal layer is not particularly limited as long as it has the above-described barrier properties, but examples include one or more selected from the group consisting of aluminum (Al), iron (Fe), copper (Cu), magnesium (Mg), nickel (Ni), tin (Sn), zinc (Zn), indium (In), and tungsten (W) (single metal or mixture of single metals), or two or more alloys selected from these. Specifically, the metal may include one or more selected from the group consisting of aluminum or its alloys, titanium or its alloys, tungsten or its alloys, molybdenum or its alloys, copper or its alloys, and stainless steel. More specifically, it may include aluminum. As one embodiment, the surface treatment layer may be a surface treatment layer of phosphoric acid, chromium, zirconium, cerium, lanthanum, scandium, yttrium, etc., in order to provide corrosion resistance to the metal.

[0033] As one embodiment, the metal layer may have a thickness of 20 μm to 80 μm. If the thickness of the metal layer is less than 20 μm, pinholes, microcracks, etc. may occur during processes such as molding, making it difficult to ensure safety. If the thickness of the metal layer exceeds 80 μm, the energy density may be low during the manufacture of the battery.

[0034] One embodiment of the present disclosure may further include an adhesive layer between the metal layer and the outer layer for bonding the metal layer and the outer layer. Another embodiment of the present disclosure may further include an adhesive layer between the sealant layer and the metal layer for bonding the metal layer and the sealant layer. Specifically, the adhesive layer may be an adhesive layer and / or an extruded resin layer. For example, the adhesive layer may contain one or more of epoxy adhesives, polyurethane adhesives, phenolic resin adhesives, polyolefin adhesives, and polyester adhesives. In one embodiment, the adhesive layer may have a thickness of 0.5 μm to 10 μm. For example, the extruded resin layer may contain an olefin resin such as a polypropylene resin. In one embodiment, the extruded resin layer may have a thickness of about 5 to 80 μm.

[0035] One embodiment of the present disclosure can provide a cell pouch including the cell pouch film described above.

[0036] Another embodiment of this disclosure can provide a method for storing the aforementioned cell pouch film, which includes a step of storing it at a temperature of 48 to 57°C. Specifically, the storage temperature may be 48°C or higher, 49°C or higher, 50°C or higher, 51°C or higher, 52°C or higher, 53°C or higher, or 54°C or higher, and 57°C or lower, 56°C or lower, 55°C or lower, 54°C or lower, 53°C or lower, 52°C or lower, or 51°C or lower. If the storage temperature exceeds 57°C, moldability may decrease, and if it is below 48°C, the slip agent may flow out in excess and aggregate, causing process defects and reducing product reliability.

[0037] In one embodiment, the storage period in the storage stage may be 10 days or more. Specifically, it may be 10 days or more, 20 days or more, 30 days or more, 40 days or more, 50 days or more, 60 days or more, 70 days or more, 80 days or more, 90 days or more, 100 days or more, 150 days or more, 200 days or more, or 250 days or more, and may also be 300 days or less, 200 days or less, 100 days or less, 90 days or less, 80 days or less, 70 days or less, 60 days or less, 50 days or less, 40 days or less, 30 days or less, or 20 days or less.

[0038] In one embodiment, the relative humidity during the storage stage may be 5% to 25%.

[0039] The present disclosure will be described in more detail below through examples. It should be obvious to those with ordinary skill in the art that these examples are merely illustrative of the disclosure and should not be construed as limiting the scope of the present disclosure.

[0040] [Manufacturing example] One embodiment of the present disclosure was manufactured by the following method.

[0041] A film for cell pouches was manufactured by forming a 25 μm outer layer of polyethylene terephthalate film on one side of a 60 μm thick metal layer made from a metal base roll of aluminum foil, and laminating an unoriented polypropylene film containing an amide-based slip agent in an amount of 0.1 to 20% by weight relative to the total weight of the sealant layer onto the other side of the metal layer to form an 80 μm sealant layer.

[0042] As one embodiment of this disclosure, a cell pouch film can be manufactured using an outer layer in which a 12 μm polyethylene terephthalate film and a 25 μm nylon film are laminated, and it was confirmed that the results of the test examples described later are the same in this case as well.

[0043] [Test Example 1] To confirm the surface roughness of the film produced in the above manufacturing example according to the storage temperature, the following experiment was conducted.

[0044] First, a lubricant testing device was prepared, consisting of a cubic metal (iron) (weighing approximately 1.3 kg) encased in a black pouch (manufactured by Kurimura Chemical Co., Ltd.). A film manufactured according to the above example, cut to a size of 50 mm x 240 mm, was fixed to a flat surface with the sealant layer facing upwards. Then, the black pouch of the device was rubbed once against the sealant layer of each film, which had been stored at different storage temperatures, at a speed of 400 mm / 10 s. Next, a 1 x 1 cm area was identified where the slip agent that had seeped out of the film had formed white stripes on the black pouch. 2 The sample was cut to size and flattened onto a glass slide using double-sided tape. The surface roughness was then measured using a surface roughness measuring device (e.g., NV-2200 3D profiler, Nano Systems) and an analysis program (NanoMap, Nano Systems).

[0045] The results of Examples 1 and 2, and Comparative Example 4 are shown in Figure 1 and Table 1.

[0046] [Table 1]

[0047] As shown in the results above, it can be confirmed that in Examples 1 and 2 of this disclosure, the surface roughness Rt falls within the range of 13 to 20 μm and Rz within the range of 10 to 15 μm by adjusting the storage temperature.

[0048] [Test Example 2] To confirm the aggregation pattern of the slip agent, the coefficient of friction, and the moldability of the film according to one embodiment of the present disclosure, the following experiments were conducted on Examples 1 and 2 and Comparative Examples 1 to 4, whose surface roughness was confirmed in Test Example 1, and the measured values ​​are shown in Tables 2 to 9. At this time, the moldability, lubricant test, and coefficient of friction of each film were measured at room temperature on day 0, and then the results were observed while storing them for 90 days at each set storage temperature.

[0049] Lubricant test The lubricant test is conducted to measure the amount or aggregation pattern of the slip agent that flows onto the surface of the sealant layer or outer layer of the cell pouch film. The same lubricant test apparatus used for the surface roughness measurement was prepared, and the manufactured film was cut to a size of 50 mm x 240 mm. After fixing the film to a flat surface with the sealant layer or outer layer facing upwards, the sealant layer or outer layer of each prepared film was rubbed against the film at a speed of 400 mm / 10 s. The process was repeated once when rubbing the sealant layer and five times when rubbing the outer layer. Next, the areas where the slip agent that had flowed out of each film had seeped out and formed white streaks on the black pouch were imaged using a scanning electron microscope (SEM, manufacturer: HITACHI, product name: SU3500), and the size of the aggregated slip agent particles was confirmed and evaluated by scanning visually. Figure 2 is a photograph of the lubricant testing apparatus used in the experiment, and Figure 3 is an image of the black pouch after the experiment, in which it can be seen that white stripes have formed on the upper part of the black pouch image. As shown in Figure 4, based on the results of visual evaluation, if white stripes were seen only on one edge and there were few scratches over most of the area, it was evaluated as grade S; if two lines were seen on the edge (white stripe area) and there were scratches from the slipper, it was evaluated as grade A (A+, A0, or A-); and if two lines were seen on the corner and the slipper was applied to the entire surface, it was evaluated as grade B.

[0050] Furthermore, during the analysis of the SEM images, the number of the largest aggregated particles of the slip agent present in the areas where the slip agent had seeped out and formed white stripes on the black pouch, and their average diameter were confirmed.

[0051] Measurement of the coefficient of friction Each of the prepared films was cut to a size of 200 x 100 mm, and the coefficient of friction of each film was measured using a friction coefficient meter (manufacturer: Labsink, product name: CF-800XS). Specifically, a 200 mm x 100 mm sample of each film was prepared and flatly attached to the bottom of the friction coefficient meter. Then, a 70 mm x 60 mm sample of the same film was attached to a jig provided on the friction coefficient meter, and the jig was then connected to the equipment with a string. The jig was placed on the equipment so that the two films were in contact, and the bottom of the equipment was moved at a speed of 15 mm / 1 s for 55 seconds. During this time, the film on the jig, which was fixed with a string, did not move, and the coefficient of friction between the two films was measured.

[0052] Measurement of moldability Each of the prepared films was cut to a size of 200 x 100 mm, then placed on a cup-shaped mold (manufacturer: GWANGSHIN HI-TECH, model: GS-S5), and a pressure of 0.3 MPa was applied to form the film into a cup shape. The maximum depth at which no cracks or tears occurred during the molding process was measured. In this case, if none of the 10 film samples showed any tearing, a deeper depth was applied, and if even one sample showed tearing, the depth immediately preceding the tear was defined as the maximum height.

[0053] Comparative Example 1 [Table 2]

[0054] Comparative Example 2 [Table 3]

[0055] Comparative Example 3 [Table 4]

[0056] Comparative Example 4 [Table 5]

[0057] Example 1 [Table 6]

[0058] Example 2 [Table 7]

[0059] Comparative Example 5 [Table 8]

[0060] Figures 5A, 5B, 6A, and 6B show the size analysis results of particles formed by the aggregation of the slip agent that leaked out after the lubricant inspection. Figures 5A and 5B are images of the film of Example 1 in the table above, and the average diameter of the largest aggregated particles present in the SEM image was 39.2 μm. Figures 6A and 6B are images of the film of Comparative Example 4 in the table above. The average diameter of the largest aggregated particles present in the SEM image of Comparative Example 4 in Figure 6A was 40.9 μm, and the average diameter of the largest aggregated particles present in the SEM image of Comparative Example 4 in Figure 6B was 97.5 μm.

[0061] The results mentioned above are summarized in the table below.

[0062] [Table 9]

[0063] As can be seen from the results above, unlike Comparative Examples 1 to 4, Examples 1 and 2 of this disclosure satisfy the range of surface roughness Rt of 13 to 20 μm and Rz of 10 to 15 μm, resulting in a reduction in the size of aggregated slip particles present on the surface of the sealant layer to 60 μm or less during the lubricant inspection. Furthermore, Examples 1 and 2 maintain a friction coefficient of 0.15 or higher for the sealant layer, and their moldability is improved by approximately 40% compared to room temperature (day 0), demonstrating excellent moldability even with a small amount of slip agent leakage.

[0064] [Test Example 3] Films were manufactured according to the above manufacturing example, and Examples 3 and 4 were prepared in which the surface roughness Rt of the film was in the range of 13-20 μm and Rz was in the range of 10-15 μm by adjusting the storage temperature, as well as Comparative Examples 5-8 which were outside the above range. In order to confirm the aggregation pattern of the slip agent, the coefficient of friction, and the moldability of the film according to the surface roughness of the film, the surface roughness, slip agent test, coefficient of friction, and moldability of each film were measured in the same manner as described in Test Examples 1 and 2, and the measured values ​​are shown in Table 10.

[0065] [Table 10]

[0066] As a result, Examples 3 and 4 of this disclosure, which satisfy the range of surface roughness Rt 13-20 and Rz 10-15, both received an S grade in the lubricant test and showed a high coefficient of friction of 0.2 or higher. Furthermore, it can be confirmed that Examples 3 and 4, despite containing the same amount of slip agent as Comparative Examples 5-8, show significantly superior moldability as the amount of slip agent flowed out is adjusted to satisfy the aforementioned surface roughness.

[0067] This disclosure can provide the following embodiments as one example.

[0068] [First Embodiment] A sealant layer containing a slip agent; A metal layer formed on the sealant layer; and An outer layer formed on the aforementioned metal layer; A cell pouch film containing, The film is a cell pouch film in which, after being stored at a temperature of 48-57°C for 30 days, a lubricant testing device is used in which a cubic metal of 1.3 kgf is wrapped in a black pouch having a matte black appearance and an outer layer made of nylon. When the front surface of the black pouch is rubbed against the sealant layer or outer layer of the film at a speed of 400 mm / 10 s, the surface roughness of the portion where the slippery agent leaked out of the film seeped out and formed white stripes on the black pouch satisfies Rt 13-20 μm and Rz 10-15 μm.

[0069] [Second Embodiment] The film according to the first embodiment, wherein, after being stored at a temperature of 48-57°C for 30 days, when a lubricant testing device is used in which a cubic metal of 1.3 kgf is wrapped in a black pouch having a matte black appearance and an outer layer made of nylon, the front surface of the black pouch is rubbed against the sealant layer or outer layer of the film at a speed of 400 mm / 10 s, and the slip agent that has seeped out from the film forms white stripes on the black pouch, the average diameter of the largest aggregated particles of the slip agent present in the area is 60 μm or less.

[0070] [Third Embodiment] The film is the film according to the first or second embodiment, wherein the coefficient of friction of the sealant layer after storage at a temperature of 48 to 57°C for 30 days is 0.15 to 0.5.

[0071] [Fourth Embodiment] The aforementioned film has a moldability of 15-25 mm after being stored at a temperature of 48-57°C for 30 days. Here, the moldability is determined by measuring the maximum depth at which tearing does not occur when a pressure of 0.3 MPa is applied to the film during one cup molding, as described in any of the first to third embodiments.

[0072] [Fifth Embodiment] The film is the film according to any of the first to fourth embodiments, which is intended for storage at a temperature of 48 to 57°C.

[0073] [Sixth Embodiment] The film is the film according to any one of the first to fifth embodiments, wherein the film contains 0.1 to 20% by weight of a slip agent relative to the total weight of the sealant layer.

[0074] [Seventh Embodiment] The slip agent comprises one or more of the following: wax-based, amide-based, siloxane, and silicone, in the film according to any of the first to sixth embodiments.

[0075] [Eighth Embodiment] The film according to any of the first to seventh embodiments, wherein the metal layer comprises one or more selected from the group consisting of aluminum or an alloy thereof, titanium or an alloy thereof, tungsten or an alloy thereof, molybdenum or an alloy thereof, copper or an alloy thereof, and stainless steel.

[0076] [Ninth Embodiment] The film according to any of the first to eighth embodiments, wherein the outer layer contains one selected from the group consisting of polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polyhydroxyaldehyde (PHA), polylactic acid (PLA), thermoplastic starch (TPS), polyvinyl alcohol (PVA), polycaprolactam (PCL), polyethylene (PE), polypropylene (PP), ethylene vinyl acetate (EVA), ethylene vinyl alcohol (EVOH), polyvinylidene chloride (PVDC), polyethylene terephthalate (PET), and nylon.

[0077] [Tenth Embodiment] The sealant layer comprises a heat-adhesive resin, as described in any of the first to ninth embodiments.

[0078] [Embodiment No. 11] A method for storing a cell pouch film according to any of the first to tenth embodiments, A storage method comprising the step of storing the aforementioned film at a temperature of 48 to 57°C.

[0079] [Twelfth Embodiment] The storage method according to the 11th embodiment, wherein the storage period in the aforementioned stage is 10 to 300 days.

[0080] [13th Embodiment] The storage method according to the 11th or 12th embodiment, wherein the relative humidity during storage in the aforementioned stage is 5% to 25%.

Claims

1. A sealant layer containing a slip agent; A metal layer formed on the sealant layer; and An outer layer formed on the aforementioned metal layer; A cell pouch film containing, The film is a cell pouch film in which, after being stored at a temperature of 48 to 57°C for 30 days, a lubricant testing device is used in which a cubic metal of 1.3 kgf is wrapped in a black pouch having a matte black appearance and an outer layer made of nylon. When the front surface of the black pouch is rubbed against the sealant layer or outer layer of the film at a speed of 400 mm / 10 s, the surface roughness of the portion where the slippery agent leaked out of the film seeped out and formed white stripes on the black pouch satisfies Rt 13 to 20 μm and Rz 10 to 15 μm.

2. The film according to claim 1, wherein, after being stored at a temperature of 48 to 57°C for 30 days, when a lubricant testing device is used in which a cubic metal of 1.3 kgf is wrapped in a black pouch having a matte black appearance and an outer layer made of nylon, the front surface of the black pouch is rubbed against the sealant layer or outer layer of the film at a speed of 400 mm / 10 s, and the slip agent that has seeped out from the film forms white stripes on the black pouch, the average diameter of the largest aggregated particles of the slip agent present in the portion is 60 μm or less.

3. The film according to claim 1, wherein the friction coefficient of the sealant layer after storage at a temperature of 48 to 57°C for 30 days is 0.15 to 0.

5.

4. The film has a moldability of 15 to 25 mm after being stored at a temperature of 48 to 57°C for 30 days. The film according to claim 1, wherein the moldability is determined by measuring the maximum depth at which tearing does not occur when a pressure of 0.3 MPa is applied to the film during one-cup molding.

5. The film according to claim 1, wherein the film is intended for storage at a temperature of 48 to 57°C.

6. The film according to claim 1, wherein the film contains 0.1 to 20% by weight of a slip agent relative to the total weight of the sealant layer.

7. The film according to claim 1, wherein the slip agent comprises one or more of wax-based, amide-based, siloxane, and silicone.

8. The film according to claim 1, wherein the metal layer comprises one or more selected from the group consisting of aluminum or an alloy thereof, titanium or an alloy thereof, tungsten or an alloy thereof, molybdenum or an alloy thereof, copper or an alloy thereof, and stainless steel.

9. The outer layer is made of polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polyhydroxyaldehyde (PHA), polylactic acid (PLA), thermoplastic starch (TPS), polyvinyl alcohol (PVA), polycaprolactam (PCL), polyethylene (PE), polypropylene (PP), and ethylene vinyl acetate (ethylene The film according to claim 1, comprising one selected from the group consisting of vinyl acetate (EVA), ethylene vinyl alcohol (EVOH), polyvinylidene chloride (PVDC), polyethylene terephthalate (PET), and nylon.

10. The film according to claim 1, wherein the sealant layer comprises a heat-adhesive resin.

11. A method for storing a cell pouch film according to any one of claims 1 to 10, A storage method comprising the step of storing the film at a temperature of 48 to 57°C.

12. The storage method according to claim 11, wherein the storage period in the aforementioned stage is 10 to 300 days.

13. The storage method according to claim 11, wherein the relative humidity during storage in the aforementioned stage is 5% to 25%.

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