Pouch film and secondary battery

Abstract

A pouch film laminate according to the present invention is a pouch film laminate comprising a sequentially laminated substrate layer, a gas barrier layer, and a sealant layer, wherein the substrate layer comprises 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 comprises a polyamide-based film and metal oxide particles.

Description

Technology Field

[0001] The present invention relates to a pouch film laminate and a secondary battery manufactured by molding the same. Background Technology

[0003] Generally, types of secondary batteries include nickel-cadmium batteries, nickel-hydrogen batteries, lithium-ion batteries, and lithium-ion polymer batteries. These 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 and backup power storage devices that store surplus generated power or 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 produce a positive electrode and a negative electrode, and these are stacked on both sides of a separator to form an electrode assembly of a predetermined shape. Then, the electrode assembly is housed in a battery case, and after injecting an electrolyte, it is sealed.

[0005] Secondary batteries are classified into pouch type and can type depending on the material of the case housing the electrode assembly. The pouch type houses the electrode assembly in a pouch made of a flexible polymer material. The can type houses the electrode assembly in a case made of materials such as metal or plastic.

[0006] A pouch, which is a case for a pouch-type secondary battery, is manufactured by performing press processing on a flexible pouch film laminate to form a cup portion. Once the cup portion is formed, an electrode assembly is housed in the inner receiving space of the cup portion and a sealing portion is sealed to manufacture a secondary battery.

[0007] Generally, a pouch film laminate is formed with multiple layers, wherein a substrate layer is laminated on one side of a metal gas barrier layer and a sealant layer is laminated on the other side. The substrate layer included in a conventional pouch film laminate is thin, susceptible to moisture permeation, and absorbs the permeated moisture. Therefore, when sealing the pouch film laminate under high temperature conditions, the moisture absorbed by the substrate layer evaporates to form bubbles, and the substrate layer is damaged due to the formation of these bubbles, resulting in a problem of reduced insulation and moldability of the pouch. The problem to be solved

[0009] The present invention provides a pouch film laminate and a pouch-type secondary battery capable of suppressing damage to the substrate layer by preventing the problem of bubbles forming due to the vaporization of moisture absorbed by the polymer in the substrate layer during pouch sealing. means of solving the problem

[0011] According to one embodiment of the present invention, a pouch film laminate comprising a sequentially laminated substrate layer, a gas barrier layer, and a sealant layer is provided, wherein the substrate layer comprises 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 the pouch film laminate comprises a polyamide-based film and metal oxide particles.

[0012] The metal oxide particles according to the present invention may include at least one selected from the group consisting of CaO, MnO, SrO, MgO, and ZnO. Average particle size D of the metal oxide particles 50 It can be 0.1 μm to 5 μm.

[0013] The second substrate layer according to the present invention may contain the metal oxide particles in an amount of 10% to 70% by weight.

[0014] The thickness of the first substrate layer may be 10 μm to 50 μm. The first substrate layer may include a polyester-based film. Specifically, the first substrate layer may include at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

[0015] The thickness of the second substrate layer may be 10 μm to 50 μm. The second substrate layer may include at least one material selected from the group consisting of nylon 6, nylon 6,6, nylon MXD6, and nylon 4,10.

[0016] The gas barrier layer according to the present invention may include aluminum.

[0017] According to another embodiment of the present invention, a pouch-type secondary battery is provided, comprising a pouch-type battery case in which an electrode assembly is housed, wherein the pouch-type battery case comprises a pouch film laminate, and the pouch film laminate comprises a substrate layer, a gas barrier layer, and a sealant layer in which the substrate layer is sequentially laminated, and the substrate layer comprises 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 comprises metal oxide particles. Effects of the invention

[0019] The present invention includes metal oxide particles in the second substrate layer, thereby removing moisture introduced from outside the pouch by hydroxylating the metal oxides before the moisture is absorbed into the polymer within the substrate layer. As a result, even when the pouch film laminate of the present invention is sealed at a high temperature, the generation of bubbles caused by the vaporization of moisture within the substrate layer can be suppressed, thus preventing damage to the substrate layer and improving the durability and lifespan characteristics of the pouch-type secondary battery. Brief explanation of the drawing

[0021] FIG. 1 is a cross-sectional view of a pouch film laminate according to the present invention. FIG. 2 is an exploded assembly diagram of a pouch-type secondary battery according to the present invention. Specific details for implementing the invention

[0022] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0023] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0024] The terms used herein are for describing the embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used herein, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components in addition to the components mentioned.

[0025] In this specification, when a part is described as including a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0026] In this specification, the description "A and / or B" means A, or B, or A and B.

[0027] In this specification, "%" means weight percent unless otherwise explicitly indicated.

[0028] In this specification, D 50 In the particle size distribution curve, it refers to the particle size corresponding to 50% of the cumulative volume. For example, the above D 50 It can be measured using the laser diffraction method. The laser diffraction method generally enables the measurement of particle sizes ranging from the submicron range to several millimeters, and can obtain results with high reproducibility and high resolution.

[0030] Pouch film laminate

[0031] A pouch film laminate according to the present invention comprises a sequentially laminated substrate layer, a gas barrier layer, and a sealant layer, wherein the substrate layer comprises 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 comprises a polyamide-based film and metal oxide particles.

[0032] FIG. 1 is a cross-sectional view of a pouch film laminate (100) according to the present invention. Hereinafter, each configuration of the pouch film laminate of the present invention will be described in more detail with reference to FIG. 1.

[0034] (1) Base layer

[0035] The substrate layer (110) is formed on the outermost layer of the pouch film laminate (100) to protect the secondary battery from friction and collision with the outside. The substrate layer (110) is made of a polymer and can electrically insulate the electrode assembly from the outside.

[0036] The thickness of the substrate layer (110) may be 5 μm to 100 μm, specifically 7 μm to 70 μm, more specifically 25 μm to 60 μm. When the thickness of the substrate layer (110) satisfies the above range, the external insulation is excellent, and the overall thickness of the pouch is not thick, so the energy density relative to the volume of the secondary battery may be excellent.

[0037] The substrate layer (110) according to the present invention may have a composite film structure formed by two or more materials forming layers. An adhesive layer may be additionally formed between each layer in the composite film structure.

[0038] Specifically, the substrate layer (110) according to the present invention may include a first substrate layer (112) and a second substrate layer (114). In this case, the first substrate layer (112) may be a layer disposed on the outermost layer of the pouch film laminate, and the second substrate layer (114) may be a layer disposed between the first substrate layer (112) and the gas barrier layer (120). The first substrate layer (112) and the second substrate layer (114) may each be made of materials with 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.

[0039] Below, the first substrate layer (112) and the second substrate layer (114) described above will each be explained in more detail.

[0041] 1) First substrate layer

[0042] The first substrate layer (112) may be a layer disposed on the outermost layer of the pouch film laminate as described above. In this case, the first substrate layer (112) may perform the function of preventing moisture penetration from the outside of the pouch.

[0043] The first substrate layer (112) may be made of one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber. Preferably, the first substrate layer (112) may include a polyester-based film having abrasion resistance and heat resistance. For example, the first substrate 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.

[0044] The thickness of the first substrate layer (112) may be 10 μm to 50 μm, specifically 10 μm to 40 μm, more specifically 12 μm to 25 μm. When the thickness of the first substrate layer (112) satisfies the above numerical range, moisture penetration into the pouch film laminate can be effectively suppressed while ensuring the insulation and moldability of the pouch. In addition, the overall thickness of the pouch is not thick, so the energy density relative to the volume of the secondary battery is excellent.

[0046] 2) Second substrate layer

[0047] The second substrate layer (114) may be a layer disposed between the first substrate layer (112) and the gas barrier layer (120) as described above. In this case, the second substrate layer (114) may serve to improve the moldability of the pouch.

[0048] The second substrate layer (114) may include at least one of polyamide-based films such as nylon 6, nylon 6,6, nylon MXD6, nylon 4,10, but is not limited thereto. Preferably, the second substrate layer (114) may include nylon 6, in which case there is an advantage of improving the moldability of the pouch due to the excellent stretching characteristics of nylon 6.

[0049] The thickness of the second substrate layer (114) may be 10 μm to 50 μm, specifically 10 μm to 40 μm, more specifically 15 μm to 35 μm. When the thickness of the second substrate layer (114) satisfies the above numerical range, it is possible to ensure the moldability of the pouch while preventing a decrease in the energy density relative to the volume of the secondary battery due to the excessive thickness of the pouch film laminate.

[0051] Meanwhile, in the case of conventional pouch film laminates, although the first substrate layer prevents moisture penetration from the outside of the pouch, moisture from the outside of the pouch can pass through the first substrate layer and reach the second substrate layer due to limitations in thickness and material. In this case, the moisture can be easily absorbed into the second substrate layer by forming hydrogen bonds with functional groups (e.g., amide structures) within the polymer contained in the second substrate layer. Consequently, when the conventional pouch film laminate is sealed at high temperatures, the moisture absorbed into the second substrate layer vaporizes, causing bubbles to form in the second substrate layer. This leads to deformation and damage to the substrate layer, resulting in a problem where the insulation and moldability of the pouch are degraded.

[0052] The present invention solves the above problem by including metal oxide particles (140) in the second substrate layer (114). Specifically, the second substrate layer (114) according to the present invention includes metal oxide particles (140). In this case, the metal oxide can remove moisture within the second substrate layer (114) by reacting with moisture introduced into the second substrate layer (114) to hydroxylate it. As a result, even if the pouch film laminate of the present invention is sealed at a high temperature, the generation of bubbles due to the vaporization of moisture within the substrate layer can be suppressed, thereby preventing damage to the substrate layer and improving the durability and lifespan characteristics of the pouch-type secondary battery.

[0054] The metal oxide particles (140) may include at least one selected from the group consisting of CaO, MnO, SrO, MgO, and ZnO. Preferably, the metal oxide particles (140) may include at least one of CaO and MgO, which are favorable for hydroxylation with moisture.

[0056] The metal oxide particles (140) included in the second substrate layer (114) may be included in an amount of 10% to 70% by weight, specifically 15% to 65% by weight, more specifically 20% to 60% by weight relative to the total weight of the second substrate layer (114). When the metal oxide particles (140) in the second substrate layer (114) are included within the above numerical range, moisture in the second substrate layer (114) can be easily removed while minimizing damage to the second substrate layer (114).

[0058] Average particle size D of metal oxide particles (140) 50 The average particle size D of the metal oxide particles (140) can be 0.1 μm to 5 μm, specifically 0.2 μm to 3 μm, more specifically 0.2 μm to 1 μm. 50When the above numerical range is satisfied, the metal oxide particles (140) can be manufactured easily, and the metal oxide particles (140) can be uniformly dispersed within the second substrate layer (114).

[0060] Additionally, the second substrate layer (114) may further include additives other than the aforementioned metal oxide particles (140). By including additives in the second substrate layer (114), the physical properties of the second substrate layer (114) can be changed. For example, as an additive to control the tensile strength of the second substrate layer (114), at least one of carbon fiber, glass fiber, and aramid fiber may be added.

[0062] (2) Gas barrier layer

[0063] The gas barrier layer (120) is laminated between the substrate layer and the sealant layer to secure the mechanical strength of the pouch, block the entry and exit of gas or moisture from outside the secondary battery, and prevent leakage of electrolyte from inside the pouch-type battery case.

[0064] The gas barrier layer (120) may be formed of metal. For example, the gas barrier layer may be a metal thin film comprising one or more metals selected from the group consisting of aluminum (Al), copper (Cu), stainless steel (SUS), nickel, titanium and invar, but is not limited thereto.

[0065] According to one embodiment of the present invention, the gas barrier layer (120) may be formed from an aluminum alloy thin film. When the gas barrier layer (120) is formed using an aluminum alloy thin film, it is possible to secure mechanical strength above a certain level, while also ensuring light weight, complementing electrochemical properties of the electrode assembly and electrolyte, and heat dissipation. The aluminum alloy thin film may include one or more metal elements other than aluminum (Al), for example, selected from the group consisting of iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), silicon (Si), and zinc (Zn).

[0066] The thickness of the gas barrier layer (120) may be 40 μm to 100 μm, specifically 50 μm to 90 μm, more specifically 55 μm to 85 μm. When the thickness of the gas barrier layer (120) satisfies the above range, the moldability and gas barrier performance are excellent when molding the cup portion.

[0068] (3) Sealant layer

[0069] The sealant layer (130) is intended to completely seal the inside of the pouch-type battery case by mutually thermally bonding at the sealing portion when the pouch-type battery case, which accommodates an electrode assembly on the inside, is sealed. To this end, the sealant layer (130) may be formed of a material having excellent thermal bonding strength.

[0070] The sealant layer (130) may be formed from a material having insulating, corrosion-resistant, and sealing properties. Specifically, since the sealant layer (130) comes into direct contact with the electrode assembly and / or electrolyte inside the pouch-type battery case, it may be formed from a material having insulating and corrosion-resistant properties. Additionally, since the sealant layer (130) must completely seal the inside of the pouch-type battery case to block material transfer between the inside and the outside, it may be formed from a material having high sealing properties (e.g., excellent thermal sealing strength). To ensure these insulating, corrosion-resistant, and sealing properties, the sealant layer (130) may be formed from a polymer material.

[0071] The sealant layer (130) may be composed of one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber, and preferably may be composed 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 (PPA), polypropylene-ethylene copolymer and / or polypropylene-butylene-ethylene terpolymer.

[0072] 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 has the effect of ensuring the sealing strength of the sealing portion while also ensuring the moldability of the pouch film laminate.

[0074] Meanwhile, the sealant layer (130) according to the present invention may have a single-layer structure made of any one material. Alternatively, the sealant layer (130) may have a composite-layer structure formed by two or more materials forming layers. 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 each 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.

[0075] It is particularly preferable that the first sealant layer be made of acid-modified polypropylene (PPa) to ensure long-term adhesion performance between the gas barrier layer and the first sealant layer. Here, the acid-modified polypropylene may be maleic anhydride polypropylene (MAH PP).

[0076] The second sealant layer may be formed from a material having insulating, corrosion-resistant, and sealing properties. Specifically, since the second sealant layer comes into direct contact with the electrode assembly (260 in FIG. 2) and / or the electrolyte inside the receiving space (224 in FIG. 2), it may be formed from a material having insulating and corrosion-resistant properties. Additionally, since the second sealant layer must completely seal the inside of the battery case to block material transfer between the inside and the outside, it may be formed from a material having high sealing properties. To ensure such insulating, corrosion-resistant, and sealing properties, the second sealant layer may be composed of one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber. Preferably, the second sealant layer may be composed of a polyolefin resin such as polypropylene (PP) and / or polyethylene (PE). In this case, the polypropylene may consist of unoriented polypropylene, acid-modified polypropylene, a polypropylene-ethylene copolymer, and / or a polypropylene-butylene-ethylene terpolymer. Here, the acid-modified polypropylene may be maleic anhydride polypropylene (MAH PP). More preferably, the second sealant layer may include unoriented polypropylene (cast polypropylene, CPP) which has heat sealing properties and high tensile strength.

[0078] Pouch-type secondary battery

[0079] Next, a pouch-type secondary battery according to the present invention will be described.

[0080] A pouch-type secondary battery according to the present invention comprises a pouch-type battery case in which an electrode assembly is housed, wherein the pouch-type battery case comprises a pouch film laminate, wherein the pouch film laminate comprises a sequentially laminated substrate layer, a gas barrier layer, and a sealant layer, wherein the substrate layer comprises a first substrate layer and a second substrate layer, wherein the second substrate layer is disposed between the first substrate layer and the gas barrier layer and comprises a polyamide-based film and metal oxide particles.

[0082] Hereinafter, each configuration of the pouch-type secondary battery of the present invention will be explained in more detail with reference to FIG. 2.

[0083] FIG. 2 is an exploded assembly diagram of a pouch-type secondary battery (200) according to the present invention. As shown in FIG. 2, 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 insulating part (290), and an electrolyte (not shown).

[0085] (1) Pouch-type battery case

[0086] The pouch-type battery case (210) can accommodate an electrode assembly (260) inside. The pouch-type battery case (210) can be manufactured by molding the pouch film laminate of the present invention described above. Since the detailed composition and physical properties of the pouch film laminate are the same as those described above, a detailed description is omitted.

[0087] The pouch film laminate can be drawn and stretched by means of a punch or the like to manufacture a 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 place for accommodating an electrode assembly and may refer to a receiving space formed in the shape of a pocket inside the cup portion (222) as the cup portion (222) is formed.

[0089] 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 shown in FIG. 2. 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 so that the electrode assembly (260) does not escape to the outside of the battery case (210). As shown in FIG. 2, the first case (220) and the second case (230) may be manufactured with one side connected to the other, but are not limited thereto and may be manufactured in various ways, such as being separated from each other and manufactured separately.

[0090] According to another embodiment of the present invention, when forming cup portions in a pouch film laminate, two symmetrical cup portions (222, 232) can be drawn and formed adjacent to each other in a single 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 shown in FIG. 2. After receiving an electrode assembly (260) in a receiving portion (224) provided in the cup portion (222) of the first case (220), a 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 receive the electrode assembly (260) from above. Accordingly, since two cup portions (222, 232) accommodate one electrode assembly (260), an electrode assembly (260) with a thicker thickness than when there is only one cup portion (222) can be accommodated. Additionally, 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 processing speed of the pouch-type secondary battery (200) can be improved and the number of sealing processes can be reduced.

[0092] The pouch-type battery case (210) can be sealed while accommodating the electrode assembly (260) so that a part of the electrode lead (280), which will be described later, i.e., the terminal part, is exposed. Specifically, when the electrode lead (280) is connected to the electrode tab (270) of the electrode assembly (260) and an insulating part (290) is formed on a part of the electrode lead (280), the electrode assembly (260) is accommodated in the receiving part (224) provided in the cup part (222) of the first case (220), and the second case (230) can cover the receiving part (224) from above. Subsequently, an electrolyte is injected into the interior of the receiving part (224), and the sealing part (250) formed on the edges of the first case (220) and the second case (230) can be sealed.

[0093] The sealing portion (250) can perform the function of sealing the receiving portion (224). Specifically, the sealing portion (250) can seal the receiving portion (224) by being formed along the edge of the receiving 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 satisfies the above numerical range, the pouch-type battery case (210) can secure sufficient sealing strength by thermal bonding.

[0094] According to the present invention, when the sealant layers of the first case (220) and the second case (230) are laminated so as to be in contact with 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 sealing portion (250) formed in the pouch-type battery case (210) may be 54% to 86%, specifically 55% to 85%, more specifically 60% to 85% relative to the thickness of the sealant layer of the pouch film laminate. When the thickness of the sealant layer of the sealing portion (250) relative to the thickness of the sealant layer of the pouch film laminate satisfies the above numerical range, it has the effect of maintaining insulation characteristics while securing sufficient sealing strength.

[0096] (2) Electrode assembly

[0097] The electrode assembly (260) can be inserted into a pouch-type battery case (210) and sealed by the pouch-type battery case (210) after the electrolyte is injected.

[0098] 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 insulate them from one another.

[0099] The positive and negative electrodes may each have a structure in which an active material slurry is coated onto an electrode current collector in the form of a metal foil or metal mesh containing aluminum and copper. The slurry can typically be formed by stirring granular active material, an auxiliary conductor, a binder, and a conductive material with added solvent. The solvent can be removed in a subsequent process.

[0100] An electrode assembly (260) can be manufactured in a predetermined shape by applying a slurry, which is a mixture of an electrode active material and a binder and / or a conductive material, to an anode current collector and a cathode current collector to manufacture an anode and a cathode, and stacking them on both sides of a separator. The types of electrode assemblies (260) may include stack type, jelly roll type, stack and folding type, etc., but are not limited thereto.

[0101] The electrode assembly (260) may include an electrode tab (270).

[0102] The electrode tab (270) is connected to the positive and negative electrodes of the electrode assembly (260), respectively, and protrudes outward from the electrode assembly (260), serving as a path 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 a terminal portion not coated with an electrode active material, i.e., a non-coated portion. The electrode tab (270) may be formed by cutting the non-coated portion or by connecting a separate conductive member to the non-coated portion using ultrasonic welding or the like. As shown in FIG. 2, the electrode tab (270) may protrude in different directions from the electrode assembly (260), but is not limited thereto and may be formed to protrude in various directions, such as protruding in parallel from one side in the same direction.

[0104] (3) Electrode lead

[0105] 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 or the like.

[0106] The electrode lead (280) is connected to the electrode assembly (260) and can 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), specifically the electrode tab (270), and the other end of the electrode lead (280) can protrude to the outside of the pouch-type battery case (210).

[0107] The electrode lead (280) may include a positive lead (282) that has one end connected to a positive tab (272) and extends in the direction in which the positive tab (272) protrudes, and a negative lead (284) that has one end connected to a negative tab (274) and extends in the direction in which the negative tab (274) protrudes. Both the positive lead (282) and the negative lead (284) may have their other ends protruding to the outside of the battery case (210). Thus, electricity generated inside the electrode assembly (260) can be supplied to the outside. Additionally, 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. The positive lead (282) and the negative lead (284) may have different materials. That is, the positive lead (282) is made of the same aluminum (Al) material as the positive current collector, and the negative lead (284) may be made of the same copper (Cu) material as the negative current collector or a copper material coated with nickel (Ni). A portion of the electrode lead (280) protruding outside the battery case (210) can be a terminal portion and electrically connected to an external terminal.

[0109] (4) Insulating part

[0110] The insulating part (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 part (290) may be formed of a non-conductive insulating material that does not conduct electricity well. Generally, the insulating part (290) is often made of 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.

[0111] The insulating portion (290) may be positioned to surround the outer surface of the electrode lead (280). Specifically, at least a portion of the electrode lead (280) may be surrounded by the insulating portion (290). In this case, the insulating portion (290) may be positioned between the electrode lead (280) and the pouch-type battery case (210). The insulating portion (290) may be located in a sealing portion (250) where the first case (220) and the second case (230) of the pouch-type battery case (210) are heat-fused, and the electrode lead (280) may be bonded to the battery case (210).

[0113] (5) Electrolyte

[0114] The pouch-type secondary battery (200) according to the present invention may further include an electrolyte (not shown) injected into the inside of the pouch-type battery case (210). The electrolyte is intended to move lithium ions generated by the electrochemical reaction of the electrodes during charging / discharging of the secondary battery (200), and may include a non-aqueous organic electrolyte, which is a mixture of a lithium salt and an organic solvent, or a polymer using a polymer electrolyte. Furthermore, the electrolyte may include a sulfide-based, oxide-based, or polymer-based solid electrolyte, and such a solid electrolyte may have flexibility that allows it to be easily deformed by an external force.

[0116] The present invention will be explained in more detail below through specific embodiments. However, the following embodiments are merely examples to aid in understanding the invention and do not limit the scope of the invention. It is obvious to those skilled in the art that various changes and modifications are possible within the scope and spirit of this description, and it is natural that such variations and modifications fall within the scope of the appended claims.

[0118] Examples and Comparative Examples

[0119] Example 1

[0120] (1) Manufacture of pouch film laminate

[0121] A nylon film was prepared having dimensions of 266 mm in width, 50 mm in length, and 25 μm in thickness, containing 15 wt% of CaO particles (average particle size D50: 0.5 μm) relative to the total weight of the nylon film.

[0122] On one side of an aluminum alloy thin film measuring 266 mm in width, 50 m in length, and 60 μm in thickness, a first adhesive film measuring 266 mm in width, 50 m in length, and 3 μm in thickness, the nylon film, a second adhesive film measuring 266 mm in width, 50 m in length, and 3 μm in thickness, and a polyethylene terephthalate (PET) film measuring 266 mm in width, 50 m in length, and 12 μm in thickness were sequentially laminated. On the other side of the aluminum alloy thin film, a polymer film containing polypropylene measuring 266 mm in width, 50 m in length, and 80 μm in thickness was laminated. As a result, a pouch film laminate having a structure in which a polypropylene-containing polymer film / aluminum alloy thin film / first adhesive film / nylon film / second adhesive film / polyethylene terephthalate film were sequentially laminated was manufactured.

[0123] Here, the polypropylene-containing polymer film is the sealant layer, the aluminum alloy thin film is the gas barrier layer, and the first adhesive film, nylon film, second adhesive film, and polyethylene terephthalate film are the substrate layer.

[0125] (2) Manufacturing of pouch-type battery case

[0126] A pouch film laminate manufactured by the above method was cut to a width of 266 mm and a length of 200 mm, then folded in half to a size of 133 mm × 200 mm so that the sealant layers meet, and then the end of the long side (200 mm) was sealed under the following two conditions to manufacture a pouch-type battery case with a sealing portion formed.

[0127] - Sealing for 1.8 seconds at 210℃ and 0.1MPa with a seal bar area of ​​200mm × 8mm

[0128] - Sealing for 1.8 seconds at 230℃ and 0.75MPa with a seal bar area of ​​200mm × 8mm

[0130] Example 2

[0131] A pouch film laminate was prepared in the same manner as in Example 1, except that the nylon film contained CaO particles at 30% by weight relative to the total weight of the nylon film.

[0132] A pouch-type battery case was manufactured in the same manner as in Example 1, except that a pouch film laminate manufactured by the above method was used.

[0134] Example 3

[0135] A pouch film laminate was prepared in the same manner as in Example 1, except that the nylon film contained CaO particles at 50% by weight relative to the total weight of the nylon film.

[0136] A pouch-type battery case was manufactured in the same manner as in Example 1, except that a pouch film laminate manufactured by the above method was used.

[0138] Example 4

[0139] A pouch film laminate was prepared in the same manner as in Example 1, except that the nylon film contained CaO particles at 65% by weight relative to the total weight of the nylon film.

[0140] A pouch-type battery case was manufactured in the same manner as in Example 1, except that a pouch film laminate manufactured by the above method was used.

[0142] Example 5

[0143] A pouch film laminate was prepared in the same manner as in Example 1, except that a polymer film containing polypropylene with a thickness of 50 μm was laminated as a sealant layer.

[0144] A pouch-type battery case was manufactured in the same manner as in Example 1, except that a pouch film laminate manufactured by the above method was used.

[0146] Comparative Example 1

[0147] A pouch film laminate was prepared in the same manner as in Example 1, except that the nylon film did not contain CaO particles.

[0148] A pouch-type battery case was manufactured in the same manner as in Example 1, except that a pouch film laminate manufactured by the above method was used.

[0150] Comparative Example 2

[0151] Nylon film not containing CaO particles, and CaO particles (average particle size D 50 A pouch film laminate was prepared in the same manner as in Example 1, except that a polyethylene terephthalate film containing 15% by weight of (0.5 μm) relative to the total weight of the polyethylene terephthalate film was used.

[0152] A pouch-type battery case was manufactured in the same manner as in Example 1, except that a pouch film laminate manufactured by the above method was used.

[0154] Experimental Example 1: Evaluation of bubble formation in the sealing part

[0155] In Examples 1 to 5 and Comparative Examples 1 and 2, respectively, the sealing portion of the pouch-type cases was visually inspected to see if it was deformed due to the formation of air bubbles. The results are shown in Table 1 below.

[0156] ○: Sealed part deformed due to air bubble formation

[0157] ×: No bubbles form and no deformation of the seal

[0159] Whether the sealing part is deformed due to the formation of air bubbles Sealing for 1.8 seconds at 210℃ and 0.1 MPa Sealing for 1.8 seconds under conditions of 230℃ and 0.75 MPa Sealing for 1.8 seconds under conditions of 230℃ and 0.75 MPa (sealing after leaving for 1 hour at 60℃ and 90% RH) Example 1 × × × Example 2 × × × Example 3 × × × Example 4 × × × Example 5 × × × Comparative Example 1 × ○ ○ Comparative Example 2 × × ○

[0160] According to Table 1, in the case of Examples 1 to 5, which contain metal oxide particles in the second substrate layer, unlike Comparative Example 1 which does not contain metal oxide, it can be confirmed that no bubbles are generated in the sealing portion of the pouch-type case even when sealed at a temperature of 230°C, and thus no deformation of the sealing portion occurs.

[0161] Meanwhile, in the case of Comparative Example 2, in which metal oxide particles were included in the first substrate layer instead of the second substrate layer, no bubbles were generated in the sealing portion of the pouch-type case even when sealed under normal temperature conditions of 230°C; however, when sealed under 230°C conditions after being left at 60°C and RH 90% for 1 hour, bubbles were generated in the sealing portion of the pouch-type case, causing deformation of the sealing portion. This is analyzed to be because when metal oxide particles are included in the outermost first substrate layer, the metal oxide particles react rapidly with moisture, thereby failing to exert the effect of removing moisture within the substrate layer thereafter. Explanation of the symbols

[0163] 100: Pouch film laminate 110: Base layer 112: First layer of record 114: Second record layer 120: Gas barrier layer 130: Sealant layer 140: Metal oxide particles 200: Pouch-type secondary battery 210: Pouch-type case 220: First case 222: Cups 224: Reception Department 230: Second case 232: Cups 240: Bridge section 250: Sealing part 260: Electrode assembly 270: Electrode tab 272: Positive tab 274: Cathode tab 280: Electrode Lead 282: Positive lead 284: Cathode Lead 290: Insulation part

Claims

Claim 1 A pouch film laminate comprising sequentially stacked substrate layers, a gas barrier layer, and a sealant layer, 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 comprises a polyamide-based film and metal oxide particles, and the metal oxide particles are dispersed within the second substrate layer. Claim 2 A pouch film laminate according to claim 1, wherein the metal oxide particles comprise at least one selected from the group consisting of CaO, MnO, SrO, MgO, and ZnO. Claim 3 In claim 1, the average particle size D of the metal oxide particles 50 A pouch film laminate having a thickness of 0.1 μm to 5 μm. Claim 4 A pouch film laminate according to claim 1, wherein the second substrate layer comprises 10% to 70% by weight of the metal oxide particles. Claim 5 A pouch film laminate according to claim 1, wherein the thickness of the first substrate layer is 10 μm to 50 μm. Claim 6 In claim 1, the pouch film laminate comprises a first substrate layer including a polyester film. Claim 7 A pouch film laminate according to claim 1, wherein the first substrate layer comprises at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Claim 8 A pouch film laminate according to claim 1, wherein the thickness of the second substrate layer is 10 μm to 50 μm. Claim 9 A pouch film laminate according to claim 1, wherein the sealant layer comprises a first sealant layer and a second sealant layer. Claim 10 A 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. Claim 11 In claim 1, the gas barrier layer comprises aluminum, forming a pouch film laminate. Claim 12 A pouch-type secondary battery comprising a pouch-type battery case housing an electrode assembly, wherein the pouch-type battery case comprises a pouch film laminate, the pouch film laminate comprises sequentially laminated substrate layers, a gas barrier layer, and a sealant layer, 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 comprises a polyamide-based film and metal oxide particles, and the metal oxide particles are dispersed within the second substrate layer.

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