Pouch film laminate and secondary battery

Abstract

The pouch film laminate according to the present invention is a pouch film laminate comprising a base layer, a gas barrier layer, and a sealant layer laminated in this order, wherein the base layer comprises a first base layer and a second base layer, and the second base layer is disposed between the first base layer and the gas barrier layer and comprises a polyamide-based film and metal oxide particles.

Description

[Technical Field]

[0001] The present invention claims the benefit of priority based on Korean Patent Application No. 10-2022-0178736, filed on December 19, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a pouch film laminate and a secondary battery produced by molding the same. [Background technology]

[0003] Generally, types of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, lithium-ion polymer batteries, etc. Such secondary batteries are used not only in small products such as digital cameras, DVD players, MP3 players, mobile phones, PDAs, portable game devices, power tools, and e-bikes, but also in large products that require high output such as electric vehicles and hybrid vehicles, as well as in power storage devices and backup power storage devices that store surplus generated power and new renewable energy.

[0004] To manufacture such a secondary battery, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to form a positive electrode and a negative electrode, which are then stacked on both sides of a separator to form an electrode assembly of a predetermined shape, and then the electrode assembly is placed in a battery case, an electrolyte is injected, and the battery case is sealed.

[0005] Secondary batteries are classified into pouch types and can types depending on the material of the case that houses the electrode assembly. Pouch types house the electrode assembly in a pouch made of flexible polymer material, while can types house the electrode assembly in a case made of metal or plastic.

[0006] The pouch, which is the case of a pouch-type secondary battery, is manufactured by pressing a flexible pouch film laminate to form a cup portion. Once the cup portion is formed, the electrode assembly is placed in the receiving space inside the cup portion, and the seal portion is sealed to manufacture the secondary battery.

[0007]

[0003] Generally, a pouch film laminate is formed of multiple layers, with a substrate layer laminated on one side of a metal gas barrier layer and a sealant layer laminated on the other side. The substrate layer included in conventional pouch film laminates is thin and vulnerable to moisture penetration, and absorbs the moisture that penetrates. Therefore, when a pouch film laminate is sealed under high-temperature conditions, the moisture absorbed in the substrate layer evaporates, generating bubbles. The generated bubbles damage the substrate layer, resulting in a problem of reduced insulation properties and formability of the pouch. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention provides a pouch film laminate and a pouch-type secondary battery that can prevent the problem of air bubbles being generated due to evaporation of moisture absorbed in a polymer in a base layer when the pouch is sealed, thereby suppressing damage to the base layer. [Means for solving the problem]

[0009] According to one embodiment of the present invention, there is provided a pouch film laminate comprising a substrate layer, a gas barrier layer, and a sealant layer laminated in that order, wherein the substrate layer comprises a first substrate layer and a second substrate layer, the second substrate layer is disposed between the first substrate layer and the gas barrier layer, and the second substrate layer comprises a polyamide-based film and metal oxide particles.

[0010] The metal oxide particles according to the present invention may contain at least one selected from the group consisting of CaO, MnO, SrO, MgO and ZnO. The average particle size D50 of the metal oxide particles may be 0.1 μm to 5 μm.

[0011] The second substrate layer according to the present invention may contain 10% by weight to 70% by weight of the metal oxide particles.

[0012] The first base layer may have a thickness of 10 μm to 50 μm. The first base layer may include a polyester film. Specifically, the first base layer may include at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

[0013] The second base layer may have a thickness of 10 μm to 50 μm.The second base layer may contain at least one selected from the group consisting of nylon 6, nylon 6,6, nylon MXD6 and nylon 4,10.

[0014] The gas barrier layer according to the present invention may comprise aluminum.

[0015] According to another embodiment of the present invention, there is provided a pouch-type secondary battery including a pouch-type battery case in which an electrode assembly is housed, wherein the pouch-type battery case includes a pouch film laminate, and the pouch film laminate includes a substrate layer, a gas barrier layer, and a sealant layer that are laminated in that order, the substrate layer includes a first substrate layer and a second substrate layer, and the second substrate layer is disposed between the first substrate layer and the gas barrier layer and includes metal oxide particles. [Effects of the Invention]

[0016] In the present invention, by incorporating metal oxide particles into the second substrate layer, moisture entering from outside the pouch can be removed by hydroxylation of the metal oxide before it is absorbed by the polymer in the substrate layer. As a result, even when the pouch film laminate of the present invention is sealed at high temperatures, the generation of bubbles due to evaporation of moisture in the substrate layer is suppressed, preventing damage to the substrate layer and improving the durability and lifespan characteristics of the pouch-type secondary battery. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view of a pouch film laminate according to the present invention. [Figure 2] 1 is an exploded view of a pouch-type secondary battery according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0018] The advantages and features of the present invention, as well as methods for achieving them, will become more apparent from the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and can be realized in various different forms. The present embodiments are provided merely to complete the disclosure of the present invention and to enable those skilled in the art to fully understand the scope of the invention. The present invention is defined only by the scope of the claims. The same reference numerals refer to the same elements throughout the specification.

[0019] Unless otherwise defined, all terms (including technical and scientific terms) used herein will be used in the sense commonly understood by those skilled in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries will not be interpreted ideally or excessively unless clearly defined otherwise.

[0020] The terms used in this specification are for the purpose of describing the embodiments and are not intended to limit the present invention. In this specification, the singular form includes the plural form unless otherwise specified in the phrase. As used in this specification, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other elements in addition to the elements being mentioned.

[0021] In this specification, when a part is said to include a certain component, it does not mean that it may further include other components, unless otherwise specified.

[0022] In this specification, the expression "A and / or B" means A, B, or A and B.

[0023] In this specification, "%" means % by weight unless expressly indicated otherwise.

[0024] In this specification, D 50 means the particle size corresponding to 50% of the cumulative volume in the particle size distribution curve. For example, D 50 can be measured using the laser diffraction method, which is generally capable of measuring particle sizes from the submicron range to several mm, and can provide results with high reproducibility and high resolution.

[0025] Pouch film laminate The pouch film laminate according to the present invention comprises a base layer, a gas barrier layer, and a sealant layer laminated in this order, the base layer comprising a first base layer and a second base layer, the second base layer being disposed between the first base layer and the gas barrier layer and comprising a polyamide film and metal oxide particles, and the sealant layer having a thickness of 50 μm to 120 μm.

[0026] 1 is a cross-sectional view of a pouch film laminate 100 according to the present invention. Each component of the pouch film laminate of the present invention will be described in more detail below with reference to FIG.

[0027] (1) Base material layer The substrate layer 110 is formed as the outermost layer of the pouch film laminate 100 to protect the secondary battery from external friction and impact. The substrate layer 110 is made of a polymer and can electrically insulate the electrode assembly from the outside.

[0028] The thickness of the base material layer 110 may be 5 μm to 100 μm, specifically 7 μm to 70 μm, and more specifically 25 μm to 60 μm. When the thickness of the base material layer 110 satisfies the above range, the external insulation is excellent, and the overall thickness of the pouch is not large, so that the secondary battery has excellent energy density relative to its volume.

[0029] The substrate layer 110 according to the present invention may have a composite membrane structure formed by layers of two or more materials, and an adhesive layer may be further formed between each layer in the composite membrane structure.

[0030] Specifically, the substrate layer 110 according to the present invention may include a first substrate layer 112 and a second substrate layer 114. In this case, the first substrate layer 112 may be a layer disposed as the outermost layer of the pouch film laminate, and the second substrate layer 114 may be a layer disposed between the first substrate layer 112 and the gas barrier layer 120. The first substrate layer 112 and the second substrate layer 114 may be made of materials having different materials and / or physical properties. An interface may exist between the first substrate layer 112 and the second substrate layer 114. This means that the first substrate layer 112 and the second substrate layer 114 are different layers and may be formed separately.

[0031] The first base material layer 112 and the second base material layer 114 will now be described in more detail.

[0032] 1) First base layer As described above, first base layer 112 may be the layer disposed on the outermost side of the pouch film laminate. In this case, first base layer 112 serves to prevent moisture from penetrating into the pouch from the outside.

[0033] The first base layer 112 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, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, Teflon (registered trademark), and glass fiber. The first base layer 112 preferably includes a polyester film having abrasion resistance and heat resistance. For example, the first base layer 112 may include at least one material selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, but is not limited thereto.

[0034] The thickness of the first base layer 112 may be 10 μm to 50 μm, specifically 10 μm to 40 μm, and more specifically 12 μm to 25 μm. When the thickness of the first base layer 112 satisfies the above numerical range, the insulation properties and formability of the pouch are ensured while the penetration of moisture into the inside of the pouch film laminate can be effectively suppressed. In addition, since the overall thickness of the pouch is not large, the energy density relative to the volume of the secondary battery is excellent.

[0035] 2) Second base material layer As described above, the second base material layer 114 may be a layer disposed between the first base material layer 112 and the gas barrier layer 120. In this case, the second base material layer 114 serves to improve the formability of the pouch.

[0036] The second base material layer 114 may include at least one of polyamide films such as, but is not limited to, nylon 6, nylon 6,6, nylon MXD6, and nylon 4,10. The second base material layer 114 preferably includes nylon 6, which has the advantage of improving the formability of the pouch due to the excellent stretchability of nylon 6.

[0037] The thickness of second base layer 114 may be 10 μm to 50 μm, specifically 10 μm to 40 μm, and more specifically 15 μm to 35 μm. When the thickness of second base layer 114 satisfies the above numerical range, it is possible to ensure the formability of the pouch while preventing a decrease in the energy density relative to the volume of the secondary battery caused by an excessive increase in the thickness of the pouch film laminate.

[0038] On the other hand, in the case of conventional pouch film laminates, although the first base layer prevents moisture from penetrating from outside the pouch, moisture from outside the pouch can sometimes pass through the first base layer and reach the second base layer due to limitations in its thickness and material. In such cases, moisture forms hydrogen bonds with functional groups (e.g., amide structures) in the polymer contained in the second base layer, making it more likely to be absorbed by the second base layer. As a result, when conventional pouch film laminates are sealed at high temperatures, the moisture absorbed in the second base layer evaporates, generating bubbles in the second base layer, which deforms and damages the base layer, resulting in problems such as reduced insulation and moldability of the pouch.

[0039] The present invention solves the above problem by incorporating metal oxide particles 140 into the second substrate layer 114. Specifically, the second substrate layer 114 according to the present invention comprises metal oxide particles 140. In this case, the metal oxide is hydroxylated by reacting with moisture that has flowed into the second substrate layer 114, thereby removing moisture from the second substrate layer 114. As a result, even when the pouch film laminate of the present invention is sealed at high temperatures, the generation of bubbles due to evaporation of moisture in the substrate layer is suppressed, preventing damage to the substrate layer and improving the durability and lifespan characteristics of the pouch-type secondary battery.

[0040] The metal oxide particles 140 may contain at least one selected from the group consisting of CaO, MnO, SrO, MgO, and ZnO. The metal oxide particles 140 preferably contain at least one of CaO and MgO, which are advantageous for hydroxylation with moisture.

[0041] The metal oxide particles 140 contained in the second base layer 114 may be contained in an amount of 10 wt % to 70 wt %, specifically 15 wt % to 65 wt %, and more specifically 20 wt % to 60 wt %, relative to the total weight of the second base layer 114. When the metal oxide particles 140 contained in the second base layer 114 are contained in the above numerical range, moisture in the second base layer 114 can be easily removed while minimizing damage to the second base layer 114.

[0042] Average particle size D of metal oxide particles 140 50 The average particle diameter D of the metal oxide particles 140 may be 0.1 μm to 5 μm, specifically 0.2 μm to 3 μm, and more specifically 0.2 μm to 1 μm. 50 When satisfies the above numerical range, the metal oxide particles 140 are easy to produce, and the metal oxide particles 140 can be uniformly dispersed in the second base material layer 114.

[0043] The second base layer 114 may further contain an additive other than the above-mentioned metal oxide particles 140. By adding an additive to the second base layer 114, it is possible to change the physical properties of the second base layer 114. For example, at least one of carbon fiber, glass fiber, and aramid fiber may be added as an additive to adjust the tensile strength of the second base layer 114.

[0044] (2) Gas barrier layer The gas barrier layer 120 is laminated between the base layer and the sealant layer to ensure the mechanical strength of the pouch, block the entry and exit of gases and moisture from outside the secondary battery, and prevent electrolyte leakage from inside the pouch-type battery case.

[0045] The gas barrier layer 120 may be formed of a metal, for example, a metal thin film containing one or more metals selected from the group consisting of aluminum (Al), copper (Cu), stainless steel (SUS), nickel, titanium, and invar (INVAR), but is not limited thereto.

[0046] According to one embodiment of the present invention, the gas barrier layer 120 may be formed of an aluminum alloy thin film. When the gas barrier layer 120 is formed using an aluminum alloy thin film, it is possible to ensure a predetermined level of mechanical strength, a light weight, and the electrochemical properties of the electrode assembly and the electrolyte, as well as heat dissipation. The aluminum alloy thin film may contain at least one metal element other than aluminum (Al), such as iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), silicon (Si), and zinc (Zn).

[0047] The thickness of the gas barrier layer 120 may be 40 μm to 100 μm, specifically 50 μm to 90 μm, and more specifically 55 μm to 85 μm. When the thickness of the gas barrier layer 120 satisfies the above range, excellent moldability during molding of the cup portion and excellent gas barrier performance are achieved.

[0048] (3) Sealant layer The sealant layer 130 is intended to completely seal the interior of the pouch-type battery case by thermally bonding the seal portions together when the pouch-type battery case, which houses the electrode assembly inside, is sealed. To this end, the sealant layer 130 may be made of a material with excellent thermal bonding strength.

[0049] The sealant layer 130 may be formed of a material having insulating properties, corrosion resistance, and sealing properties. Specifically, since the sealant layer 130 is in direct contact with the electrode assembly and / or electrolyte inside the pouch-type battery case, it may be formed of a material having insulating properties and corrosion resistance. Furthermore, since the sealant layer 130 must completely seal the interior of the pouch-type battery case to prevent the transfer of materials between the inside and outside, it may be formed of a material having high sealing properties (e.g., excellent thermal adhesive strength). To ensure such insulating properties, corrosion resistance, and sealing properties, the sealant layer 130 may be formed of a polymer material.

[0050] The sealant layer 130 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, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, Teflon (registered trademark), and glass fiber, and is preferably made of a polyolefin resin such as polypropylene (PP) and / or polyethylene (PE). In this case, the polypropylene may be made of cast polypropylene (CPP), acid-modified polypropylene (PPa), polypropylene-ethylene copolymer, and / or polypropylene-butylene-ethylene terpolymer.

[0051] The thickness of the sealant layer 130 may be 50 μm to 120 μm, specifically 70 μm to 100 μm. When the thickness of the sealant layer satisfies the above range, it is possible to ensure the formability of the pouch film laminate while ensuring the seal strength of the sealed portion.

[0052] Meanwhile, the sealant layer 130 according to the present invention may have a single film structure made of any one material. Alternatively, the sealant layer 130 may have a composite film structure formed by layers of two or more materials. Specifically, the sealant layer 130 may include a first sealant layer and a second sealant layer. In this case, the first sealant layer may be a layer disposed adjacent to the gas barrier layer, and the second sealant layer may be a layer disposed on the first sealant layer. The first sealant layer and the second sealant layer may be made of materials with different materials and / or physical properties. An interface may exist between the first sealant layer and the second sealant layer. This means that the first sealant layer and the second sealant layer are different layers and may be formed separately.

[0053] In order to ensure long-term adhesion between the gas barrier layer and the first sealant layer, it is particularly preferable that the first sealant layer is made of acid-modified polypropylene (PPa), which may be maleic anhydride polypropylene (MAH PP).

[0054] The second sealant layer may be formed of a material having insulating, corrosion-resistant, and sealing properties. Specifically, since the second sealant layer is in direct contact with the electrode assembly (260 in FIG. 2) and / or the electrolyte inside the accommodating space (224 in FIG. 2), it may be formed of a material having insulating and corrosion-resistant properties. Furthermore, since the second sealant layer must completely seal the interior of the battery case to prevent the transfer of materials between the inside and outside, it may be formed of a material having high sealing properties. To ensure such insulating, corrosion-resistant, and sealing properties, the second sealant layer 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, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, Teflon, and glass fiber. The second sealant layer is preferably made of a polyolefin resin such as polypropylene (PP) and / or polyethylene (PE). In this case, the polypropylene may be composed of unstretched polypropylene, acid-modified polypropylene, polypropylene-ethylene copolymer, and / or polypropylene-butylene-ethylene terpolymer. Here, the acid-modified polypropylene may be maleic anhydride polypropylene (MAH PP). More preferably, the second sealant layer contains cast polypropylene (CPP), which has heat sealability and high tensile strength.

[0055] Pouch-type secondary battery Next, the pouch-type secondary battery according to the present invention will be described.

[0056] The pouch-type secondary battery according to the present invention includes a pouch-type battery case in which an electrode assembly is housed, the pouch-type battery case including a pouch film laminate, the pouch film laminate including a substrate layer, a gas barrier layer, and a sealant layer laminated in that order, the substrate layer including a first substrate layer and a second substrate layer, the second substrate layer being disposed between the first substrate layer and the gas barrier layer and including a polyamide-based film and metal oxide particles.

[0057] Hereinafter, each component of the pouch-type secondary battery of the present invention will be described in more detail with reference to FIG.

[0058] 2 is an exploded view of a pouch-type secondary battery 200 according to the present invention. As shown in FIG. 2, the pouch-type secondary battery 200 according to the present invention may include a pouch-type battery case 210, an electrode assembly 260, an electrode lead 280, an insulating part 290, and an electrolyte (not shown).

[0059] (1) Pouch-type battery case The pouch-type battery case 210 may house the electrode assembly 260 inside. The pouch-type battery case 210 may be manufactured by molding the pouch film laminate of the present invention described above. The detailed structure and physical properties of the pouch film laminate are as described above, so a detailed description thereof will be omitted.

[0060] The pouch film laminate may be drawn and stretched using a punch or the like to manufacture the pouch-type battery case 210. As a result, the pouch-type battery case 210 may include a cup portion 222 and a receiving portion 224. The receiving portion 224 is a portion that receives the electrode assembly, and may refer to a pocket-shaped receiving space formed inside the cup portion 222 by forming the cup portion 222.

[0061] According to one embodiment of the present invention, the pouch-type battery case 210 may include a first case 220 and a second case 230, as shown in Fig. 2. The first case 220 may include a receiving portion 224 that can receive the electrode assembly 260, and the second case 230 may cover the receiving portion 224 from above to prevent the electrode assembly 260 from falling out of the battery case 210. The first case 220 and the second case 230 may be manufactured with one side connected to each other as shown in Fig. 2, but the present invention is not limited thereto and may be manufactured in various ways, such as being separated from each other and separately manufactured.

[0062] According to another embodiment of the present invention, when forming cup portions in a pouch film laminate, two symmetrical cup portions 222, 232 may be adjacent to one another by drawing molding. In this case, the first case 220 and the second case 230 may be formed with the cup portions 222, 232, respectively, as shown in FIG. 2 . The electrode assembly 260 may be accommodated in the accommodation portion 224 of the cup portion 222 of the first case 220, and then the bridge portion 240 formed between the two cup portions 222, 232 may 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. Therefore, since two cup portions 222, 232 accommodate one electrode assembly 260, a thicker electrode assembly 260 can be accommodated than when there is only one cup portion 222. In addition, since one edge of the secondary battery 200 is formed by folding the pouch-type battery case 210, the number of edges to be sealed in a subsequent sealing process is reduced, thereby improving the processing speed of the pouch-type secondary battery 200 and reducing the number of sealing processes.

[0063] The pouch-type battery case 210 may be sealed with the electrode assembly 260 housed therein so that a portion of the electrode lead 280, i.e., a terminal portion, described below, is exposed. Specifically, after 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 may be housed in a housing portion 224 provided in the cup portion 222 of the first case 220, and the housing portion 224 may be covered from above by the second case 230. Next, an electrolyte may be injected into the housing portion 224, and the seal portion 250 formed on the edges of the first case 220 and the second case 230 may be sealed.

[0064] The sealing portion 250 serves to seal the accommodating portion 224. Specifically, the sealing portion 250 may be formed along the edge of the accommodating portion 224 to seal the accommodating portion 224. The temperature at which the sealing portion 250 is sealed may be 180°C to 250°C, specifically 200°C to 250°C, and more specifically 210°C to 240°C. When the sealing temperature is within the above range, the pouch-type battery case 210 can ensure sufficient seal strength through thermal bonding.

[0065] According to the present invention, when the sealant layers of the first case 220 and the second case 230 are laminated so that they abut against each other and then sealed for 1.6 seconds under conditions of 210°C and 1.2 MPa, the thickness of the sealant layer of the seal portion 250 formed in the pouch-type battery case 210 may be 54% to 86%, specifically 55% to 85%, and more specifically 60% to 85%, of the thickness of the sealant layer of the pouch film laminate. When the thickness of the sealant layer of the seal portion 250 relative to the thickness of the sealant layer of the pouch film laminate satisfies the above numerical range, there is an effect of ensuring sufficient sealing strength while maintaining insulating properties.

[0066] (2) Electrode assembly The electrode assembly 260 may be inserted into the pouch-type battery case 210, and after the electrolyte is injected, the pouch-type battery case 210 may be sealed.

[0067] The electrode assembly 260 may be formed by sequentially stacking a positive electrode, a separator, and a negative electrode. Specifically, the electrode assembly 260 may include two types of electrodes, a positive electrode and a negative electrode, and a separator interposed between the electrodes to insulate the electrodes from each other.

[0068] The positive electrode and the negative electrode may have a structure in which an active material slurry is applied to an electrode current collector in the form of a metal foil or a metal mesh containing aluminum and copper, respectively. The slurry may be formed by stirring a granular active material, an auxiliary conductor, a binder, a conductive material, etc., in a solvent. The solvent may be removed in a subsequent process.

[0069] 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 form a positive electrode and a negative electrode, which are then stacked on both sides of a separator to form a predetermined shape of the electrode assembly 260. Types of the electrode assembly 260 include, but are not limited to, a stack type, a jelly roll type, and a stack-and-fold type.

[0070] The electrode assembly 260 may include an electrode tab 270 .

[0071] The electrode tabs 270 are connected to the positive and negative electrodes of the electrode assembly 260, respectively, and protrude from the electrode assembly 260 to serve as paths for electrons to move between the inside and outside of the electrode assembly 260. The electrode current collector included in the electrode assembly 260 may be composed of a portion coated with an electrode active material and an end portion, i.e., a plain portion, where the electrode active material is not coated. The electrode tabs 270 may be formed by cutting the plain portion or by connecting a separate conductive member to the plain portion by ultrasonic welding or the like. As shown in FIG. 2, the electrode tabs 270 may protrude in different directions from the electrode assembly 260, but are not limited thereto. They may be formed to protrude in various directions, such as protruding in parallel from one side in the same direction.

[0072] (3) Electrode lead The electrode lead 280 can supply electricity to the outside of the secondary battery 200. The electrode lead 280 may be connected to the electrode tab 270 of the electrode assembly 260 by spot welding or the like.

[0073] An electrode lead 280 may be connected to the electrode assembly 260 and may protrude to the outside of the pouch-type battery case 210 via the seal portion 250. Specifically, one end of the electrode lead 280 may be 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.

[0074] The electrode lead 280 may include a positive electrode lead 282 having one end connected to the positive electrode tab 272 and extending in the direction in which the positive electrode tab 272 protrudes, and a negative electrode lead 284 having one end connected to the negative electrode tab 274 and extending in the direction in which the negative electrode tab 274 protrudes. The other ends of the positive electrode lead 282 and the negative electrode lead 284 may protrude to the outside of the battery case 210. This allows electricity generated inside the electrode assembly 260 to be supplied to the outside. Furthermore, since the positive electrode tab 272 and the negative electrode tab 274 protrude in different directions, the positive electrode lead 282 and the negative electrode lead 284 may also extend in different directions. The positive electrode lead 282 and the negative electrode lead 284 may be made of different materials. That is, the positive electrode lead 282 may be made of aluminum (Al), the same material as the positive electrode current collector, and the negative electrode lead 284 may be made of copper (Cu) or nickel (Ni)-coated copper, the same material as the negative electrode current collector. The part of the electrode lead 280 that protrudes outside the battery case 210 may serve as a terminal portion and be electrically connected to an external terminal.

[0075] (4) Insulation section The insulating portion 290 prevents electricity generated from the electrode assembly 260 from flowing to the battery case 210 via the electrode lead 280, thereby maintaining the sealing of the battery case 210. To this end, the insulating portion 290 may be formed of an insulator that is electrically non-conductive and does not easily conduct electricity. Generally, the insulating portion 290 is formed of a relatively thin insulating tape or film that is easily attached to the electrode lead 280, but the insulating portion 290 is not limited thereto, and any material that can insulate the electrode lead 280 may be used.

[0076] The insulating portion 290 may be arranged to surround the outer peripheral surface of the electrode lead 280. Specifically, at least a portion of the electrode lead 280 may be surrounded by the insulating portion 290. In this case, the insulating portion 290 may be arranged between the electrode lead 280 and the pouch-type battery case 210. The insulating portion 290 may be located in a limited area of ​​the seal portion 250 where the first case 220 and the second case 230 of the pouch-type battery case 210 are heat-sealed, and the electrode lead 280 may be bonded to the battery case 210.

[0077] (5) Electrolyte The pouch-type secondary battery 200 according to the present invention may further include an electrolyte (not shown) injected into the pouch-type battery case 210. The electrolyte is for transporting lithium ions generated by an electrochemical reaction of the electrodes during charging / discharging of the secondary battery 200, and may include a non-aqueous organic electrolytic solution that is a mixture of a lithium salt and an organic solvent, or a polymer using a polymer electrolyte. The electrolyte may also include a sulfide-based, oxide-based, or polymer-based solid electrolyte, and such a solid electrolyte may have flexibility that makes it easily deformable under external force.

[0078] The present invention will be described in more detail below with reference to specific examples. However, the following examples are merely illustrative to aid in understanding the present invention and are not intended to limit the scope of the present invention. It is obvious to those skilled in the art that various changes and modifications can be made within the scope and technical concept of the present description, and it is obvious that such changes and modifications are included in the scope of the appended claims.

[0079] Examples and Comparative Examples Example 1 (1) Manufacturing of pouch film laminates The size is 266 mm wide, 50 mm long, and 25 μm thick. 50 A nylon film containing 15% by weight of cellulose acylate (0.5 μm) based on the total weight of the nylon film was prepared.

[0080] On one side of an aluminum alloy thin film measuring 266 mm wide, 50 mm long, and 60 μm thick, a first adhesive film measuring 266 mm wide, 50 mm long, and 3 μm thick, the nylon film, a second adhesive film measuring 266 mm wide, 50 mm long, and 3 μm thick, and a polyethylene terephthalate (PET) film measuring 266 mm wide, 50 mm long, and 12 μm thick were sequentially laminated. On the other side of the aluminum alloy thin film, a polymer film containing polypropylene measuring 266 mm wide, 50 mm long, and 80 μm thick was laminated. As a result, a pouch film laminate was produced having a structure in which a polymer film containing polypropylene / aluminum alloy thin film / first adhesive film / nylon film / second adhesive film / polyethylene terephthalate film were sequentially laminated.

[0081] Here, the polymer film containing polypropylene is a sealant layer, the aluminum alloy thin film is a gas barrier layer, and the first adhesive film, nylon film, second adhesive film and polyethylene terephthalate film are base layers.

[0082] (2) Manufacturing pouch-type battery cases The pouch film laminate produced by the above method was cut to a size of 266 mm wide and 200 mm long, then folded in half so that the sealant layers were in contact to make a size of 133 mm wide x 200 mm long, and then the ends of the long sides (200 mm) were sealed under the following two conditions to produce pouch-type battery cases with sealed portions.

[0083] -Seal bar area 200mm x 8mm, seal for 1.8 seconds under conditions of 210℃ and 0.1MPa -Seal bar area 200mm x 8mm, seal for 1.8 seconds under conditions of 230℃ and 0.75MPa

[0084] Example 2 A pouch film laminate was produced in the same manner as in Example 1, except that the nylon film contained CaO particles in an amount of 30 wt % based on the total weight of the nylon film.

[0085] A pouch-type battery case was produced in the same manner as in Example 1, except that the pouch film laminate produced by the above method was used.

[0086] Example 3 A pouch film laminate was produced in the same manner as in Example 1, except that the nylon film contained CaO particles in an amount of 50 wt % based on the total weight of the nylon film.

[0087] A pouch-type battery case was produced in the same manner as in Example 1, except that the pouch film laminate produced by the above method was used.

[0088] Example 4 A pouch film laminate was produced in the same manner as in Example 1, except that the nylon film contained 65 wt % of CaO particles relative to the total weight of the nylon film.

[0089] A pouch-type battery case was produced in the same manner as in Example 1, except that the pouch film laminate produced by the above method was used.

[0090] Example 5 A pouch film laminate was produced in the same manner as in Example 1, except that a 50 μm thick polymer film containing polypropylene was laminated as a sealant layer.

[0091] A pouch-type battery case was produced in the same manner as in Example 1, except that the pouch film laminate produced by the above method was used.

[0092] Comparative Example 1 A pouch film laminate was produced in the same manner as in Example 1, except that the nylon film did not contain CaO particles.

[0093] A pouch-type battery case was produced in the same manner as in Example 1, except that the pouch film laminate produced by the above method was used.

[0094] Comparative Example 2 Nylon film containing no CaO particles and CaO particles (average particle size D 50 A pouch film laminate was produced in the same manner as in Example 1, except that a polyethylene terephthalate film containing 15% by weight of polyethylene terephthalate (0.5 μm) based on the total weight of the polyethylene terephthalate film was used.

[0095] A pouch-type battery case was produced in the same manner as in Example 1, except that the pouch film laminate produced by the above method was used.

[0096] Experimental example 1: Evaluation of the presence or absence of bubbles in the sealing area The pouch-shaped cases produced in Examples 1 to 5 and Comparative Examples 1 and 2 were visually inspected to see if there were any bubbles in the sealed portion and thus deformation of the sealed portion. The results are shown in Table 1 below. ○: Air bubbles are generated and the seal is deformed ×: No bubbles are generated and the seal is not deformed

[0097] [Table 1]

[0098] According to Table 1, in Examples 1 to 5 in which metal oxide particles are contained in the second substrate layer, unlike Comparative Example 1, it can be confirmed that no air bubbles are generated in the sealed portion of the pouch-type case and no deformation of the sealed portion occurs even when sealed at a temperature condition of 230°C.

[0099] On the other hand, in the case of Comparative Example 2, in which metal oxide particles were contained in the first base layer instead of the second base layer, no air bubbles were generated in the sealed portion of the pouch-shaped case when it was sealed at the normal temperature condition of 230°C. However, when it was left at 60°C and RH 90% for 1 hour and then sealed at 230°C, air bubbles were generated in the sealed portion of the pouch-shaped case, causing deformation of the sealed portion. This is analyzed to be because when metal oxide particles are contained in the outermost first base layer, the metal oxide particles react quickly with moisture, preventing them from subsequently removing moisture from the base layer. [Explanation of symbols]

[0100] 100 Pouch film laminate 110 Base material layer 112 1st base layer 114 Second base layer 120 Gas barrier layer 130 Sealant Layer 140 Metal oxide particles 200 Pouch-type secondary battery 210 Pouch-type case 220 Case 1 222 Cup section 224 Storage Unit 230 Case 2 232 Cup section 240 Bridge section 250 Seal part 260 Electrode assembly 270 Electrode Tab 272 Positive electrode tab 274 Negative electrode tab 280 Electrode Lead 282 Positive lead 284 Negative lead 290 Insulation

Claims

1. A pouch film laminate comprising a base layer, a gas barrier layer, and a sealant layer laminated in this order, the substrate layer includes a first substrate layer and a second substrate layer, The pouch film laminate, wherein the second base material layer is disposed between the first base material layer and the gas barrier layer and includes a polyamide-based film and metal oxide particles.

2. The pouch film laminate according to claim 1 , wherein the metal oxide particles include at least one selected from the group consisting of CaO, MnO, SrO, MgO, and ZnO.

3. The average particle diameter D of the metal oxide particles ５０ The pouch film laminate according to claim 1, wherein the thickness is 0.1 μm to 5 μm.

4. The pouch film laminate according to claim 1, wherein the second substrate layer contains 10% by weight to 70% by weight of the metal oxide particles.

5. The pouch film laminate according to claim 1, wherein the thickness of the first base layer is 10 μm to 50 μm.

6. The pouch film laminate according to claim 1 , wherein the first base layer comprises a polyester-based film.

7. The pouch film laminate according to claim 1 , wherein the first base layer comprises at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

8. The pouch film laminate according to claim 1, wherein the second base layer has a thickness of 10 μm to 50 μm.

9. The pouch film laminate of claim 1 , wherein the sealant layer comprises a first sealant layer and a second sealant layer.

10. The pouch film laminate according to claim 1 , wherein the second substrate layer comprises at least one selected from the group consisting of nylon 6, nylon 6,6, nylon MXD6, and nylon 4,10.

11. The pouch film laminate according to claim 1 , wherein the gas barrier layer comprises aluminum.

12. A pouch-type secondary battery including a pouch-type battery case in which an electrode assembly is housed, the pouch-type battery case includes a pouch film laminate; The pouch film laminate includes a base layer, a gas barrier layer, and a sealant layer, which are laminated in this order, the substrate layer includes a first substrate layer and a second substrate layer, the second base layer is disposed between the first base layer and the gas barrier layer, and includes a polyamide film and metal oxide particles.

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