Soft film laminate and secondary battery

Abstract

A soft envelope laminate according to the present invention includes a base layer, a gas barrier layer, and a sealant layer laminated in this order, in which the base layer includes 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 includes a polyamide base film and metal oxide particles.

Description

Technical Field

[0001] This application claims the benefit of Korean Patent Application No. 10-2022-0178736, filed with the Korean Intellectual Property Office on December 19, 2022, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates to a soft package laminate and a secondary battery manufactured by molding the soft package laminate. Background Art

[0004] Generally, secondary batteries are classified into several different types: nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, and lithium-ion polymer batteries. Such secondary batteries are used in various categories, including: for example, small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, portable game devices, power tools, and electric bicycles, and large products that require high power such as electric vehicles and hybrid vehicles, power storage devices for storing surplus power or renewable energy, and backup power storage devices.

[0005] When manufacturing a secondary battery, first, an electrode active material slurry is coated on a positive electrode current collector and a negative electrode current collector to prepare a positive electrode and a negative electrode, and the positive electrode and the negative electrode are laminated on both sides of a separator to form an electrode assembly having a predetermined shape. Subsequently, the electrode assembly is accommodated in a battery case, an electrolyte is injected into the battery case, and the battery case is sealed.

[0006] Secondary batteries are classified into soft-pack type secondary batteries and can type secondary batteries according to the material of the case that accommodates the electrode assembly. The soft-pack type secondary battery accommodates the electrode assembly in a soft pack formed of a flexible polymer material. The can type secondary battery accommodates the electrode assembly in a case formed of a material such as metal or plastic.

[0007] The soft pack, which is the case of the soft-pack type secondary battery, is prepared by performing pressing processing on a flexible soft package laminate to form a cup portion. Once the cup portion is formed, the electrode assembly is accommodated in the inner accommodation space of the cup portion, and a sealing portion is sealed to manufacture a secondary battery.

[0008] Generally, the soft package laminate is formed of multiple layers in which a base layer is laminated on one side of a metal gas barrier layer and a sealant layer is laminated on the other side. The base layer included in the conventional soft package laminate is thin, easily permeated by moisture, and absorbs the permeated moisture. Therefore, when the soft package laminate is sealed at a high temperature, the moisture inhaled into the base layer evaporates to generate bubbles, and the base layer is damaged due to the generated bubbles, resulting in a reduction in the insulation performance and formability of the soft pack. Summary of the Invention

[0009] Technical problem

[0010] One aspect of the present invention provides a soft package laminate and a soft package secondary battery that can prevent bubbles from being generated due to the evaporation of moisture in the polymer sucked into the base layer during sealing of the soft package, thereby suppressing damage to the base layer.

[0011] Technical solution

[0012] According to one aspect of the present invention, there is provided a soft package laminate including a base layer, a gas barrier layer, and a sealant layer laminated in sequence, wherein the base layer includes 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 includes a polyamide-based film and metal oxide particles.

[0013] The metal oxide particles according to the present invention may include at least one material selected from the group consisting of CaO, MnO, SrO, MgO, and ZnO. The average particle size D of the metal oxide particles 50 may be from 0.1 μm to 5 μm.

[0014] The second base layer according to the present invention may include 10 wt% to 70 wt% of metal oxide particles.

[0015] The thickness of the first base layer may be from 10 μm to 50 μm. The first base layer may include a polyester-based film. Specifically, the first base layer may include at least one material selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

[0016] The thickness of the second base layer may be from 10 μm to 50 μm. The second base layer may include at least one material selected from the group consisting of nylon 6, nylon (6,6), nylon MXD6, and nylon (4,10).

[0017] The gas barrier layer according to the present invention may contain aluminum.

[0018] According to another aspect of the present invention, there is provided a soft package secondary battery including a soft package battery case containing an electrode assembly, wherein the soft package battery case includes a soft package laminate including a base layer, a gas barrier layer, and a sealant layer laminated in sequence, the base layer includes 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 includes a polyamide-based film and metal oxide particles.

[0019] Advantageous effects

[0020] In the present invention, since the second base layer contains metal oxide, the metal oxide is hydroxylated before moisture introduced from the outside of the pouch is absorbed into the polymer in the base layer, and thus the moisture can be removed. Therefore, even when the pouch film laminate of the present invention is sealed at a high temperature, generation of bubbles due to evaporation of moisture in the base layer can be suppressed, damage to the base layer can be prevented, and the durability and life characteristics of the pouch-type secondary battery can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a cross-sectional view of a pouch film laminate according to the present invention; and

[0022] Figure 2 is an exploded view of a pouch-type secondary battery according to the present invention. DETAILED DESCRIPTION

[0023] Advantages and features of the present disclosure and a method of implementing the present disclosure can be more easily understood with reference to the following detailed description of embodiments and the accompanying drawings. However, the present disclosure may be implemented in different forms, and these embodiments are only for making the present disclosure thorough and complete, and fully conveying the scope of the present disclosure to those skilled in the art. Therefore, the present disclosure is only defined by the scope of the appended claims. Throughout the specification, the same reference numerals denote the same elements.

[0024] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. Terms defined in commonly used dictionaries are not ideally or overly interpreted unless clearly and specifically defined otherwise.

[0025] The terms used herein are not intended to limit the inventive concept, but to describe embodiments. As used herein, unless the context clearly indicates otherwise, the singular forms also include the plural forms. The meaning of "comprising" and / or "including" as used herein does not exclude the presence or addition of one or more other components in addition to the components mentioned.

[0026] In this document, when an element "comprises" a component, unless there is a contrary clear description, this may mean that the element does not exclude another component, but may also include another component.

[0027] In this document, the description "A and / or B" means A or B or A and B.

[0028] In this document, unless otherwise indicated, "%" means wt%.

[0029] The term "D" used herein 50” can be defined as the particle size at which the cumulative volume in the particle size distribution curve of the particles is 50%. For example, D can be measured by using a laser diffraction method. 50 The laser diffraction method generally allows measurement of particle sizes from the sub-micron level to several millimeters and can produce highly reproducible and high-resolution results.

[0030] Soft-coated laminate

[0031] The soft-coated laminate according to the present invention includes a base layer, a gas barrier layer, and a sealant layer laminated in sequence, and the base layer includes a first base layer and a second base layer. The second base layer is disposed between the first base layer and the gas barrier layer and includes a polyamide-based film and metal oxide particles, and the thickness of the sealant layer is 50 μm to 120 μm.

[0032] Figure 1 is a cross-sectional view of the soft-coated laminate 100 according to the present invention. Hereinafter, each component of the soft-coated laminate of the present invention will be described in more detail with reference to Figure 1 Each component of the soft-coated laminate of the present invention will be described in more detail.

[0033] (1) Base layer

[0034] The base layer 110 is formed on the outermost layer of the soft-coated laminate 100 to protect the secondary battery from external friction and collision. Since the base layer 110 is made of a polymer, the electrode assembly can be electrically insulated from the outside.

[0035] The thickness of the base 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 layer 110 satisfies the above range, the external insulation is excellent and the entire soft package is not thick, so the energy density to volume ratio of the secondary battery can be excellent.

[0036] The base layer 110 according to the present invention may have a composite film structure in which two or more materials are formed into layers respectively. In the composite film structure, an adhesive layer may be additionally formed between the respective layers.

[0037] Specifically, the base layer 110 according to the present invention may include a first base layer 112 and a second base layer 114. In this case, the first base layer 112 may be a layer provided on the outermost layer of the soft-coated laminate, and the second base layer 114 may be a layer provided between the first base layer 112 and the gas barrier layer 120. The first base layer 112 and the second base layer 114 may be formed of materials having different masses and / or physical properties respectively. There may be an interface between the first base layer 112 and the second base layer 114. This means that the first base layer 112 and the second base layer 114 are different layers and can be formed separately.

[0038] Hereinafter, each of the above-mentioned first base layer 112 and second base layer 114 will be described in more detail.

[0039] 1) First base layer

[0040] As described above, the first base layer 112 can be a layer provided on the outermost layer of the soft package laminate. In this case, the first base layer 112 can be used to prevent moisture from penetrating from the outside of the soft package.

[0041] The first base layer 112 can be formed of at least one material selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly(p-phenylene terephthalamide benzoxazole), polyarylate, Teflon, and glass fiber. Preferably, the first base layer 112 can include a polyester-based film having wear resistance and heat resistance. For example, the first base layer 112 can include at least one material selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, but is not limited thereto.

[0042] The thickness of the base layer 112 can 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, moisture penetration into the soft package laminate can be effectively suppressed, and the insulation performance and formability of the soft package can also be achieved. In addition, the entire soft package is not thick, so the energy density to volume ratio of the secondary battery is excellent.

[0043] 2) Second base layer

[0044] As described above, the second base layer 114 can be a layer provided between the first base layer 112 and the gas barrier layer 120. In this case, the second base layer 114 can be used to improve the formability of the soft package.

[0045] The second base layer 114 can include at least one polyamide-based film such as nylon 6, nylon (6,6), nylon MXD6, and nylon (4,10), but is not limited thereto. Preferably, the second base layer 114 can contain nylon 6, and in this case, due to the excellent tensile properties of nylon 6, it has the advantage of improving the formability of the soft package.

[0046] The thickness of the second base layer 114 can be 10 μm to 50 μm, specifically 10 μm to 40 μm, and more specifically 15 μm to 35 μm. When the thickness of the second base layer 114 satisfies the above numerical range, a decrease in the energy density to volume ratio of the secondary battery due to an excessive thickness of the soft package laminate can be prevented, and the formability of the soft package can also be achieved.

[0047] Meanwhile, in a conventional soft package laminate, although the first base layer prevents moisture from penetrating from the outside of the soft package, due to the limitations of thickness and material, the moisture outside the soft package can pass through the first base layer and reach the second base layer. In this case, the moisture can be easily absorbed into the second base layer by forming hydrogen bonds with functional groups (e.g., amide structure) in the polymer contained in the second base layer. Therefore, when the conventional soft package laminate is sealed at a high temperature, the moisture absorbed into the second base layer evaporates, thus generating bubbles in the second base layer, which leads to deformation and damage of the base layer, thereby reducing the insulation performance and formability of the soft package.

[0048] The present invention solves the above problems by including metal oxide particles 140 in the second base layer 114. Specifically, the second base layer 114 according to the present invention includes metal oxide particles 140. In this case, the metal oxide is hydroxylated by reacting with the moisture introduced into the second base layer 114, thereby removing the moisture in the second base layer 114. Therefore, even when the soft package laminate of the present invention is sealed at a high temperature, the generation of bubbles caused by the evaporation of moisture in the base layer can be suppressed to prevent damage to the base layer and improve the durability and life characteristics of the soft package secondary battery.

[0049] The metal oxide particles 140 may include at least one material selected from the group consisting of CaO, MnO, SrO, MgO, and ZnO. Preferably, the metal oxide particles 140 may include at least one material of CaO and MgO that is favorable for hydroxylation with moisture.

[0050] Based on the total weight of the second base layer 114, the content of the metal oxide particles 140 contained in the second base layer 114 may be 10 wt% to 70 wt%, specifically 15 wt% to 65 wt%, and more specifically 20 wt% to 60 wt%. When the metal oxide particles 140 in the second base layer 114 are within the above numerical range, the moisture in the second base layer 114 can be easily removed and the damage to the second base layer 114 can be minimized.

[0051] The average particle size D of the metal oxide particles 140 50 may be 0.1 μm to 5 μm, specifically 0.2 μm to 3 μm, and more specifically 0.2 μm to 1 μm. When the average particle size D of the metal oxide particles 140 50 satisfies the above numerical range, it is easy to prepare the metal oxide particles 140, and the metal oxide particles 140 can be uniformly dispersed in the second base layer 114.

[0052] In addition, the second base layer 114 may further include additives other than the above-mentioned metal oxide particles 140. The additives included in the second base layer 114 may change the physical properties of the second base layer 114. For example, as an additive for controlling the tensile strength of the second base layer 114, at least any one of carbon fiber, glass fiber, and aramid fiber may be added.

[0053] (2) Gas barrier layer

[0054] The gas barrier layer 120 is laminated between the base layer and the sealant layer to ensure the mechanical strength of the soft package, block the entry and exit of gas or moisture outside the secondary battery, and prevent the electrolyte from leaking from the inside of the soft package type battery case.

[0055] The gas barrier layer 120 may be formed of a metal. For example, the gas barrier layer may be a metal thin film including at least one metal selected from the group consisting of aluminum (Al), copper (Cu), stainless steel (SUS), nickel, titanium, and INVAR, but is not limited thereto.

[0056] According to an 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 of an aluminum alloy thin film, the gas barrier layer may have a predetermined level of mechanical strength and be light in weight, and may supplement the electrochemical performance caused by the electrode assembly and the electrolyte and dissipate heat. The aluminum alloy thin film may include metal elements other than aluminum (Al). For example, it may include at least one selected from the group consisting of iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), silicon (Si), and zinc (Zn).

[0057] 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, the formability and gas barrier performance are excellent when molding the cup portion.

[0058] (3) Sealant layer

[0059] When sealing the soft package type battery case that houses the electrode assembly inside to completely seal the inside of the soft package type battery case, the sealant layers 130 are thermally bonded together at the sealing portion. For this purpose, the sealant layer may be made of a material having excellent heat seal strength.

[0060] The sealant layer 130 can be made of a material with insulation, corrosion resistance, and sealing properties. Specifically, the sealant layer 130 is in direct contact with the electrode assembly and / or electrolyte inside the pouch-type battery case, and thus can be formed of a material with insulation and corrosion resistance. Additionally, the sealant layer 130 should completely seal the inside of the pouch-type battery case and prevent the movement of substances between the inside and the outside, so it can be formed of a material with high sealing performance (e.g., excellent heat-sealing strength). To ensure such insulation, corrosion resistance, and sealing properties, the sealant layer 130 can be formed of a polymer material.

[0061] The sealant layer 130 can be formed of at least one material selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly(p-phenylene terephthalamide benzoxazole), polyarylate, Teflon, and glass fiber, and preferably can be formed of a polyolefin-based resin such as polypropylene (PP) and / or polyethylene (PE). In this case, the polypropylene can be provided with cast polypropylene (CPP), acid-modified polypropylene (PPa), polypropylene-ethylene copolymer, and / or polypropylene-butene-ethylene terpolymer.

[0062] The thickness of the sealant layer 130 can 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 seal part and ensuring the formability of the pouch film laminate.

[0063] Meanwhile, the sealant layer 130 according to the present invention can have a single-layer film structure formed of any one material. Alternatively, the sealant layer 130 can have a composite film structure in which two or more materials are respectively formed into layers. Specifically, the sealant layer 130 can include a first sealant layer and a second sealant layer. In this case, the first sealant layer can be the layer disposed adjacent to the gas barrier layer, and the second sealant layer can be the layer disposed on the first sealant layer. The first sealant layer and the second sealant layer can be formed of materials with different masses and / or physical properties. An interface can 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 can be formed separately.

[0064] Particularly preferably, the first sealant layer is formed of acid-modified polypropylene (PPa) to obtain long-term adhesiveness between the gas barrier layer and the first sealant layer. In this case, the acid-modified polypropylene can be maleic anhydride polypropylene (MAHPP).

[0065] The second sealant layer may be formed of a material having insulation, corrosion resistance, and sealing properties. Specifically, the second sealant layer is in direct contact with the electrode assembly 260 ( Figure 2 ) and / or the electrolyte inside the accommodation space 224 ( Figure 2 ), and thus may be formed of a material having insulation and corrosion resistance. In addition, the second sealant layer should completely seal the inside of the pouch-type battery case and prevent substances from moving between the inside and the outside, and thus may be formed of a material having high sealing performance. To obtain insulation, corrosion resistance, and sealing properties, the second sealant layer may be formed of at least one material selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly(p-phenylene terephthalamide benzoxazole), polyarylate, Teflon, and glass fiber. Preferably, the second sealant layer may be formed of a polyolefin-based resin such as, for example, polypropylene (PP) and / or polyethylene (PE). In this case, the polypropylene may be provided with cast polypropylene, acid-modified polypropylene, polypropylene-ethylene copolymer, and / or polypropylene-butene-ethylene terpolymer. In this case, the acid-modified polypropylene may be maleic anhydride polypropylene (MAH PP). More preferably, the second sealant layer may include cast polypropylene (CPP) having heat sealability and high tensile strength.

[0066] Pouch-type secondary battery

[0067] Next, a pouch-type secondary battery according to the present invention will be described.

[0068] The pouch-type secondary battery according to the present invention includes a pouch-type battery case accommodating an electrode assembly, wherein 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 laminated in this order, the base layer includes a first base layer and a second base layer, and the second base layer is provided between the first base layer and the gas barrier layer and includes a polyamide-based film and metal oxide particles.

[0069] Hereinafter, each component of the pouch-type secondary battery of the present invention will be described in more detail with reference to Figure 2 FIG.

[0070] Figure 2 is an exploded view of a pouch-type secondary battery 200 according to the present invention. As Figure 2 shown, the pouch-type secondary battery 200 of the present invention may include a pouch-type battery case 210, an electrode assembly 260, electrode leads 280, an insulating part 290, and an electrolyte (not shown).

[0071] (1) Pouch-type battery case

[0072] The pouch-type battery case 210 can store the electrode assembly 260 therein. The pouch-type battery case 210 can be manufactured by molding the soft film laminate of the present invention described above. The detailed composition and physical properties of the soft film laminate are the same as those described above, and thus no detailed description is provided.

[0073] The soft film laminate can be pulled out, molded, or stretched by a punch or the like to manufacture the pouch-type battery case 210. Accordingly, the pouch-type battery case 210 can include a cup portion 222 and a receiving portion 224. The receiving portion 224 is a position for storing the electrode assembly, and can represent a receiving space formed in a concave shape inside the cup portion 222 when the cup portion 222 is formed.

[0074] According to an embodiment of the present invention, the pouch-type battery case 210 can include a first case 220 and a second case 230, as Figure 2 shown. The first case 220 can include a receiving portion 224 capable of receiving the electrode assembly 260, and the second case 230 can cover the receiving portion 224 from above to prevent the electrode assembly 260 from separating to the outside of the battery case 210. As Figure 2 shown, the first case 220 and the second case 230 can be manufactured in such a manner that one side of the first case 220 can be connected to one side of the second case 230, but the embodiments of the present invention are not limited thereto, and the first case 220 and the second case 230 can be manufactured differently, for example, separately manufactured separately from each other.

[0075] According to another embodiment of the present invention, when forming the cup portion in the soft film laminate, two symmetric cup portions 222 and 232 can be stretched and molded adjacent to each other in one soft film laminate. In this case, the cup portions 222 and 232 can be respectively formed in the first case 220 and the second case 230, as Figure 2 shown. After the electrode assembly 260 is received in the receiving portion 224 provided in the cup portion 222 of the first case 220, the bridging portion 240 formed between the two cup portions 222 and 232 can be folded so that the two cup portions 222 and 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, the two cup portions 222 and 232 receive one electrode assembly 260, and thus can receive a thicker electrode assembly 260 than when only one cup portion 222 is present. In addition, one edge of the secondary battery 200 is formed by folding the pouch-type battery case 210, and thus, the number of edges to be sealed can be reduced when performing a sealing process later. Accordingly, the process speed of the pouch-type secondary battery 200 can be increased and the number of sealing processes can be reduced.

[0076] While accommodating the electrode assembly 260, the pouch-type battery case 210 can be sealed, thereby exposing a part of the electrode lead 280, i.e., the terminal portion, which will be described later. Specifically, when the electrode lead 280 is connected to the electrode tab 270 of the electrode assembly 260 and the insulating portion 290 is formed on a part of the electrode lead 280, the electrode assembly 260 can be accommodated in the accommodating portion 224 provided in the cup portion 222 of the first case 220, and the second case 230 can cover the accommodating portion 224 from above. Then, the electrolyte is injected into the accommodating portion 224, and the sealing portion 250 formed on the edges of the first case 220 and the second case 230 can be sealed.

[0077] The sealing portion 250 can be used to seal the accommodating portion 224. Specifically, the sealing portion 250 can be formed along the edge of the accommodating portion 224, so that the accommodating portion 224 can be sealed. The temperature at which the sealing portion 250 is sealed can be 180°C to 250°C, specifically 200°C to 250°C, and more specifically 210°C to 240°C. When the sealing temperature satisfies the above numerical range, the pouch-type battery case 210 can obtain sufficient sealing strength through thermal sealing.

[0078] According to the present invention, when the sealant layers of the first case 220 and the second case 230 are laminated to contact each other and then sealed at 210°C and 1.2 MPa for 1.6 seconds, the thickness of the sealant layer of the sealing portion 250 formed in the pouch-type battery case 210 can be 54% to 86% of the thickness of the sealant layer of the pouch film laminate, specifically 55% to 85%, and more specifically 60% to 85%. When the thickness of the sealant layer of the sealing portion 250 satisfies the above numerical range compared with the thickness of the sealant layer of the pouch film laminate, there is an effect of maintaining the insulation performance while obtaining sufficient sealing strength.

[0079] (2) Electrode assembly

[0080] The electrode assembly 260 can be inserted into the pouch-type battery case 210 and sealed by the pouch-type battery case 210 after the electrolyte is injected.

[0081] The positive electrode, the separator, and the negative electrode can be laminated in sequence to form the electrode assembly 260. Specifically, the electrode assembly 260 can include two types of electrodes, i.e., the positive electrode and the negative electrode, and a separator interposed between the electrodes to insulate the electrodes from each other.

[0082] The positive electrode and the negative electrode can have a structure in which an active material paste is respectively coated on an electrode current collector in the form of a metal foil or a metal mesh containing aluminum and copper. Generally, granular active materials, auxiliary conductors, binders, and conductive materials are stirred with an added solvent to form a paste. The solvent can be removed in subsequent processes.

[0083] A slurry mixed with an electrode active material, a binder, and / or a conductive material is coated onto a positive electrode current collector and a negative electrode current collector to fabricate a positive electrode and a negative electrode, and the positive electrode and the negative electrode are stacked on both sides of a separator. Thus, the electrode assembly 260 can be fabricated into a predetermined shape. The types of the electrode assembly 260 may include: a stacked type, a gel roll type, and a stacked and folded type, but are not limited thereto.

[0084] The electrode assembly 260 may include an electrode tab 270.

[0085] The electrode tab 270 is connected to each of the positive electrode and the negative electrode of the electrode assembly 260 and protrudes outward from the electrode assembly 260. Thus, it can be used as a path through which electrons move between the inside and the outside of the electrode assembly 260. The current collector included in the electrode assembly 260 may be provided with a portion coated with the electrode active material and an end portion not coated with the 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 by ultrasonic welding or the like. As Figure 2 shown, the electrode tab 270 may protrude from the electrode assembly 260 in different directions, but is not limited thereto, and may be formed to protrude in various directions. For example, it may protrude from one side in the same direction.

[0086] (3) Electrode lead

[0087] The electrode lead 280 may supply power 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.

[0088] The 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 sealing 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.

[0089] The electrode lead 280 may include: a positive electrode lead 282, one end of the positive electrode lead 282 being 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, one end of the negative electrode lead 284 being connected to the negative electrode tab 274 and extending in the direction in which the negative electrode tab 274 protrudes. The other ends of both the positive electrode lead 282 and the negative electrode lead 284 may protrude to the outside of the battery case 210. Accordingly, the electric power generated inside the electrode assembly 260 can be supplied to the outside. In addition, since the positive electrode tab 272 and the negative electrode tab 274 are each formed to 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 from each other. That is, the positive electrode lead 282 may be made of the same aluminum (Al) material as the positive electrode current collector, and the negative electrode lead 284 may be made of the same copper (Cu) or nickel (Ni)-coated copper material as the negative electrode current collector. A part of the electrode lead 280 protruding to the outside of the battery case 210 may serve as a terminal portion and be electrically connected to an external terminal.

[0090] (4) Insulating portion

[0091] The insulating portion 290 may prevent the electric power generated from the electrode assembly 260 from flowing through the electrode lead 280 to the battery case 210 and can maintain the sealing of the battery case 210. For this purpose, the insulating portion 290 may be made of a non-conductive non-conductor through which electricity does not flow well. Generally, as the insulating portion 290, a relatively thin insulating tape or insulating film that is easily attached to the electrode lead 280 is usually used, but embodiments of the present invention are not limited thereto, and thus any member capable of insulating the electrode lead 280 may be used.

[0092] The insulating portion 290 may be provided to surround the outer circumferential surface of the electrode lead 280. Specifically, at least a part of the electrode lead 280 may be surrounded by the insulating portion 290. In this case, the insulating portion 290 may be provided between the electrode lead 280 and the pouch-type battery case 210. The insulating portion 290 may be provided to be restricted at the sealing portion 250, to which the first case 220 and the second case 230 of the pouch-type battery case 210 are heat-sealed, and may bond the electrode lead 280 to the battery case 210.

[0093] (5) Electrolyte

[0094] 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 used to move lithium ions generated by the electrochemical reaction of the electrodes during charging and discharging of the secondary battery 200, and may include a non-aqueous organic electrolyte solution that is a mixture of a lithium salt and an organic solvent or a polymer using a polymer electrolyte. Additionally, the electrolyte may include a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a polymer-based solid electrolyte, and such a solid electrolyte may be flexible and thus easily deformed under an external force.

[0095] Hereinafter, the present invention will be described in more detail through specific examples. However, the examples shown below are only for understanding the present invention, and the scope of the concept of the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications and changes can be made within the scope and technical scope of the present invention, and such modifications and changes fall within the scope of the claims included herein.

[0096] Examples and Comparative Examples

[0097] Example 1

[0098] Example 1: Preparation of a Pouch Film Laminate

[0099] A nylon film having a width of 266 mm, a length of 50 m, and a thickness of 25 μm and having a CaO particle content of 15 wt% (average particle diameter D 50 : 0.5 μm) based on the total weight of the nylon film was prepared.

[0100] A first adhesive film having a width of 266 mm, a length of 50 m, and a thickness of 3 μm; the nylon film, a second adhesive film having a width of 266 mm, a length of 50 m, and a thickness of 3 μm, and a polyethylene terephthalate (PET) film having a width of 266 mm, a length of 50 m, and a thickness of 12 μm were sequentially laminated on one side of an aluminum alloy film having a width of 266 mm, a length of 50 m, and a thickness of 60 μm. A polymer film containing polypropylene having a width of 266 mm, a length of 50 m, and a thickness of 80 μm was laminated on the other side of the aluminum alloy film. Thus, a pouch film laminate having a structure in which the polymer film containing polypropylene, the aluminum alloy film, the first adhesive film / nylon film, the second adhesive film, and the polyethylene terephthalate film are sequentially laminated was prepared.

[0101] In this case, the polymer film containing polypropylene is a sealant layer, the aluminum alloy film is a gas barrier layer, and the first adhesive film, the nylon film, the second adhesive film, and the polyethylene terephthalate film are base layers.

[0102] (2) Preparation of a Pouch-Type Battery Case

[0103] The soft-coated laminate prepared by the above method is cut to a width of 266 mm and a length of 200 mm, and then folded in half into a size of 133 mm × 200 mm so that the sealant layers are in contact, and then sealed at the ends of the long side (200 mm) under the following two conditions to prepare a pouch-type battery case in which a sealed portion is formed therein.

[0104] Seal for 1.8 seconds at 210 °C and 0.1 MPa with a seal strip area of 200 mm × 8 mm

[0105] Seal for 1.8 seconds at 230 °C and 0.75 MPa with a seal strip area of 200 mm × 8 mm Example 2

[0106] A soft-coated laminate is prepared in the same manner as in Example 1 except that the content of CaO particles in the nylon film is 30 wt% based on the total weight of the nylon film.

[0107] A pouch-type battery case is prepared in the same manner as in Example 1 except that the soft-coated laminate prepared by the above method is used.

[0108] Example 3

[0109] A soft-coated laminate is prepared in the same manner as in Example 1 except that the content of CaO particles in the nylon film is 50 wt% based on the total weight of the nylon film.

[0110] A pouch-type battery case is prepared in the same manner as in Example 1 except that the soft-coated laminate prepared by the above method is used.

[0111] Example 4

[0112] A soft-coated laminate is prepared in the same manner as in Example 1 except that the content of CaO particles in the nylon film is 65 wt% based on the total weight of the nylon film.

[0113] A pouch-type battery case is prepared in the same manner as in Example 1 except that the soft-coated laminate prepared by the above method is used.

[0114] Example 5

[0115] A soft-coated laminate is prepared in the same manner as in Example 1 except that a polymer film containing polypropylene with a thickness of 50 μm is laminated as the sealant layer.

[0116] A pouch-type battery case is prepared in the same manner as in Example 1 except that the soft-coated laminate prepared by the above method is used.

[0117] Comparative Example 1

[0118] A soft-coated laminate was prepared in the same manner as in Example 1, except that the nylon film did not contain CaO particles.

[0119] A soft-pack type battery case was prepared in the same manner as in Example 1, except that the soft-coated laminate prepared by the above method was used.

[0120] Comparative Example 2

[0121] A soft-coated laminate was prepared in the same manner as in Example 1, except that the nylon film did not contain CaO particles and the content of CaO particles in the polyethylene terephthalate film was 15 wt% (average particle size D 50 : 0.5 μm) based on the total weight of the polyethylene terephthalate film.

[0122] A soft-pack type battery case was prepared in the same manner as in Example 1, except that the soft-coated laminate prepared by the above method was used.

[0123] Experimental Example 1: Evaluation of the presence of bubbles in the sealed portion

[0124] Visually determine whether the sealed portion of the soft-pack type cases prepared in Examples 1 to 5 and Comparative Examples 1 and 2 was deformed due to the bubbles generated in the sealed portion. The results are shown in Table 1 below.

[0125] O: Bubbles were generated and the sealed portion was deformed.

[0126] X: No bubbles were generated and the sealed portion was not deformed

[0127] [Table 1]

[0128]

[0129]

[0130] From Table 1, it can be seen that, unlike Comparative Example 1, in Examples 1 to 5 in which the second base layer included metal oxide particles, even when sealed at 230 °C, no bubbles were shown in the sealed portion of the soft-pack type case and the sealed portion was not deformed.

[0131] Meanwhile, in Comparative Example 2 in which the metal oxide particles were included in the first base layer instead of the second base layer, no bubbles were shown in the sealed portion of the soft-pack type case even when sealed under normal temperature conditions of 230 °C, but when placed at 60 °C and 90% RH for 1 hour and then sealed at 230 °C, bubbles appeared in the sealed portion of the soft-pack type case, resulting in deformation of the sealed portion. This is considered to be because when the outermost layer of the first base layer included metal oxide particles, the metal oxide particles reacted rapidly with moisture, thus having no effect of removing the moisture in the base layer.

[0132] [Explanation of Reference Numerals]

[0133] 100: Soft film laminate

[0134] 110: Basal layer

[0135] 112: First base layer

[0136] 114: Second base layer

[0137] 120: Gas barrier layer

[0138] 130: Sealant layer

[0139] 140: Metal oxide particles

[0140] 200: Soft pack secondary battery

[0141] 210: Soft-pack housing

[0142] 220: First shell

[0143] 222: Cup Department

[0144] 224: Accommodation

[0145] 230: Second shell

[0146] 232: Cup Department

[0147] 240: Bridge

[0148] 250: Sealing part

[0149] 260: Electrode assembly

[0150] 270: Electrode terminal

[0151] 272: Positive terminal lug

[0152] 274: Negative terminal lug

[0153] 280: Electrode lead

[0154] 282: Positive lead

[0155] 284: Negative lead

[0156] 290: Insulation

Claims

1. A soft package laminate, comprising a base layer, a gas barrier layer, and a sealant layer laminated in sequence, Among them, wherein the base layer includes 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 includes a polyamide-based film and metal oxide particles.

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

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

4. The soft film laminate according to claim 1, wherein, The second base layer includes 10 wt% to 70 wt% of the metal oxide particles.

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

6. The soft film laminate according to claim 1, wherein, The first base layer includes a polyester-based film.

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

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

9. The soft film laminate according to claim 1, wherein, The sealant layer includes a first sealant layer and a second sealant layer.

10. The soft film laminate according to claim 1, wherein, The second base layer contains at least one material selected from the group consisting of nylon 6, nylon (6,6), nylon MXD6, and nylon (4,10).

11. The soft film laminate according to claim 1, wherein, The gas barrier layer contains aluminum.

12. A soft-pack secondary battery, the soft-pack secondary battery including a soft-pack battery case containing an electrode assembly, Among them, wherein the soft-pack battery case includes a soft package laminate, the soft package laminate includes a base layer, a gas barrier layer, and a sealant layer laminated in sequence, the base layer includes 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 includes a polyamide-based film and metal oxide particles.

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