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

Abstract

The present invention relates to a pouch film laminate comprising a substrate layer, a gas barrier layer, and a sealant layer that are sequentially stacked, wherein the pouch film laminate comprises a silicone-based release coating layer coated on the sealant layer, the thickness of the silicone-based release coating layer is 1 μm or less, the silicone-based release coating layer includes a silicone-based release agent, and the silicone-based release agent is crosslinked with a silicone-based polymer having a weight average molecular weight of less than 1,000,000 g / mol.

Description

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

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2024-0052218, dated April 18, 2024, the entire contents of which are incorporated herein by reference.

[0003]

[0004] Technology field

[0005] The present invention relates to a pouch film laminate, a pouch-type battery case, and a pouch-type secondary battery.

[0006]

[0007] Secondary batteries are used not only in small products such as digital cameras, P-DVDs, MP3 players, mobile phones, PDAs, portable game devices, power tools, and e-bikes, but also in large products requiring high output such as electric vehicles and hybrid vehicles, as well as in power storage devices that store surplus generated power or renewable energy and power storage devices for backup purposes.

[0008] Typically, secondary batteries are manufactured by applying electrode active material slurry to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode, laminating them on both sides of a separator to form an electrode assembly of a predetermined shape, then housing the electrode assembly in a battery case, injecting electrolyte, and sealing it.

[0009] Secondary batteries are classified into pouch types and can types, depending on the material of the case housing the electrode assembly. Pouch types house the electrode assembly in a pouch made of a flexible polymer material. Can types house the electrode assembly in a case made of metal or plastic.

[0010] A pouch-type battery case is manufactured by forming a cup portion by performing press processing on a flexible pouch film laminate. Then, once the cup portion is formed, an electrode assembly is accommodated in the cup portion's receiving space and a sealing portion is sealed to manufacture a secondary battery.

[0011] Among these press processes, drawing forming is performed by inserting a pouch film into a press device and applying pressure to the pouch film laminate with a punch to stretch the pouch film laminate. The pouch film laminate is generally formed of multiple layers, each of which has a polymer film, such as polyethylene terephthalate, laminated on one side of a metal gas barrier layer and a sealant layer laminated on the other side.

[0012] With the recent rise in demand for high-capacity batteries, such as those for electric vehicles and energy storage systems (ESS), there is a growing need for battery cases capable of accommodating more electrode assemblies. Accordingly, attempts are being made to increase the depth of the cup molding in pouch-type battery cases, or to create a two-cup molding method that increases the volume of the cups by molding them separately in the upper and lower cases.

[0013] In the conventional manufacturing of pouch film laminates, an activator was incorporated into the innermost sealant layer of the pouch film or applied to the surface of the sealant layer to prevent adhesion between pouch films and facilitate post-processing. However, this method had the problem of activator components remaining on the surface of the sealant layer, causing contamination of the mold during pouch molding during the secondary battery manufacturing process.

[0014] Therefore, there is a need to develop a pouch film laminate to improve the productivity of secondary batteries by preventing contamination of molds, increasing processability, and reducing cleaning frequency.

[0015]

[0016] The present invention is intended to solve the above problems, and provides a pouch film laminate, a pouch-type battery case, and a pouch-type secondary battery, which prevent contamination of a mold to increase processability, lower the coefficient of friction, and improve wrinkles and deterioration of formability that occur during cup molding.

[0017]

[0018] [1] The present invention provides a pouch film laminate comprising a sequentially laminated substrate layer, a gas barrier layer, and a sealant layer, wherein the pouch film laminate comprises a silicone-based release coating layer coated on the sealant layer, the silicone-based release coating layer has a thickness of 1 ㎛ or less, the silicone-based release coating layer comprises a silicone-based release agent, and the silicone-based release agent is a silicone-based polymer crosslinked with a weight average molecular weight of less than 1,000,000 g / mol.

[0019] [2] In the present invention, in the above [1], the silicone polymer may be at least one selected from the group consisting of polydimethylsiloxane (PDMS), polysilane, polycarbosilane, polysilazane, etc.

[0020] [3] In the present invention, in the above [1] or [2], the silicone-based release coating layer may include a polyolefin-based resin, and the silicone-based release coating layer may include the silicone-based release agent in an amount of 80 wt% or more based on the total weight of the silicone-based release coating layer.

[0021] [4] The present invention is characterized in that, in at least one of the above [1] to [3], the amount of the active agent present on the surface of the sealant layer is 1 mg / m 2 It may be less than.

[0022] [5] In at least one of the above [1] to [4], the friction coefficient of the sealant layer may be 0.05 to 0.30.

[0023] [6] In at least one of the above [1] to [5], the substrate layer may include at least one of polyethylene terephthalate (PET) and nylon.

[0024] [7] In at least one of the above [1] to [6], the thickness of the substrate layer may be 5 µm to 70 µm.

[0025] [8] In at least one of the above [1] to [7], the gas barrier layer may include at least one metal selected from the group consisting of aluminum (Al), copper (Cu), stainless steel (SUS), nickel (Ni), titanium (Ti), and invar.

[0026] [9] In at least one of the above [1] to [8], the thickness of the gas barrier layer may be 20 µm to 100 µm.

[0027]

[0010] In at least one of the above [1] to [9], the sealant layer may include at least one selected from polypropylene (PP), acid-modified polypropylene (PPa), and non-stretched polypropylene (CPP).

[0028]

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

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

[0029]

[0012] In at least one of the above [1] to

[0011] , the thickness of the pouch film laminate may be 120 µm to 300 µm.

[0030]

[0013] The present invention provides a pouch-shaped battery case manufactured by drawing and molding at least one pouch film laminate among the above [1] to

[0012] .

[0031]

[0014] The present invention provides a pouch-type secondary battery including the pouch-type battery case of the above

[0013] .

[0032]

[0033] The pouch film laminate according to the present invention forms a silicone-based release coating layer on a sealant layer, thereby lowering the coefficient of friction, and by not including a lubricant, lowering the lubricant cleaning cycle of the mold, thereby improving processability, and by generating wrinkles during cup molding, thereby improving the formability of the pouch film laminate.

[0034]

[0035] The drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the contents of the invention described above, serve to further enhance the understanding of the technical spirit of the present invention. Therefore, the present invention is not limited to the matters described in these drawings. Meanwhile, the shape, size, scale, or ratio of elements in the drawings included in this specification may be exaggerated to emphasize a clearer explanation.

[0036] Fig. 1 is a cross-sectional view of a pouch film laminate according to the present invention.

[0037] Figure 2 is an exploded assembly diagram of a secondary battery according to the present invention.

[0038]

[0039] Hereinafter, the present invention will be described in more detail.

[0040] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best possible manner.

[0041] The terminology used herein is for the purpose of describing embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms, unless specifically stated otherwise. As used herein, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components in addition to the components mentioned.

[0042]

[0043] Pouch film laminate

[0044] First, a pouch film laminate (1) according to the present invention will be described. Fig. 1 illustrates a pouch film laminate (1) according to the present invention.

[0045] Referring to FIG. 1, a pouch film laminate (1) according to the present invention includes a sequentially laminated substrate layer (10), a gas barrier layer (20), and a sealant layer (30), and includes a silicone-based release coating layer (40) on the sealant layer (30).

[0046] In the conventional manufacturing of pouch film laminates, in order to prevent adhesion between pouch film laminates and facilitate post-processing, an activator was included in the sealant layer of the innermost layer of the pouch film or applied to the surface of the sealant layer so that an activator existed on the surface of the sealant layer. However, there was a problem that the activator on the surface of the sealant layer contaminated the mold, requiring frequent cleaning, which lowered the processability.

[0047] Therefore, when a separate silicone-based release coating layer is coated on the surface of the sealant layer, a pouch film laminate having superior processability and formability can be manufactured compared to a case where an active agent is included or applied.

[0048]

[0049] Hereinafter, each configuration of the pouch film laminate according to the present invention will be described in more detail with reference to FIG. 1.

[0050]

[0051] (1) Substrate layer

[0052] The substrate layer (10) is arranged on the outermost layer of the battery case to protect the electrode assembly from external impact and electrically insulate it. The substrate layer (10) may include at least one of polyethylene terephthalate (PET) and nylon.

[0053] According to one embodiment, the substrate layer (10) may have a laminated structure of a polyethylene terephthalate (PET) film (12) and a nylon film (14). At this time, it is preferable that the nylon film (14) is disposed on the gas barrier layer (20) side, i.e., on the inside, and the polyethylene terephthalate film (12) is disposed on the surface side of the battery case.

[0054] Polyethylene terephthalate (PET) has excellent durability and electrical insulation properties, and when a PET film is placed on the surface side, it exhibits excellent durability and insulation properties. However, in the case of the PET film, the adhesion with the aluminum alloy thin film constituting the gas barrier layer (20) is weak, and the stretching behavior is also different. Therefore, when the PET film is placed on the gas barrier layer side, the substrate layer and the gas barrier layer may be peeled off during the forming process, and the gas barrier layer may not be stretched uniformly, which may cause a problem of reduced formability. In contrast, since the stretching behavior of a nylon film is similar to that of an aluminum alloy thin film constituting the gas barrier layer (20), when a nylon film is placed between the polyethylene terephthalate and the gas barrier layer, an effect of improving formability can be obtained.

[0055] The thickness of the above substrate layer (10) may be 5 µm to 70 µm, specifically 7 µm to 65 µm, and more specifically 10 µm to 60 µm. When the above range is satisfied, excellent formability and post-formation rigidity may be exhibited.

[0056] In addition, when the substrate layer (10) has a laminated structure of a polyethylene terephthalate (PET) film (12) and a nylon film (14), the polyethylene terephthalate film may have a thickness of 5 μm to 30 μm, specifically 7 μm to 30 μm, and more specifically 10 μm to 27 μm, and the nylon film may have a thickness of 10 μm to 60 μm, specifically 10 μm to 55 μm, and more specifically 15 μm to 50 μm. When the thicknesses of the polyethylene terephthalate film and the nylon film satisfy the above ranges, excellent formability and post-formed rigidity may be exhibited.

[0057]

[0058] (2) Gas barrier layer

[0059] The gas barrier layer (20) is laminated between the substrate layer (10) and the sealant layer (30) to secure the mechanical strength of the pouch, block the ingress of gas or moisture from outside the secondary battery, and prevent electrolyte leakage from inside the pouch-type battery case.

[0060] The gas barrier layer (20) may be formed of a metal. For example, the gas barrier layer may be a metal thin film including one or more metals selected from the group consisting of aluminum (Al), copper (Cu), stainless steel (SUS), nickel (Ni), titanium (Ti), and invar (INVAR), but is not limited thereto.

[0061] According to one embodiment of the present invention, the gas barrier layer (20) may be formed of an aluminum alloy thin film. When the gas barrier layer (20) is formed using an aluminum alloy thin film, a mechanical strength higher than a predetermined level can be secured, while being light in weight and ensuring complementary electrochemical properties and heat dissipation properties due to the electrode assembly and electrolyte. The aluminum alloy thin film may contain elements other than aluminum (Al). For example, the aluminum alloy thin film may contain at least one selected from the group consisting of iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), silicon (Si), and zinc (Zn).

[0062] In another example, the gas barrier layer (20) may be formed of a stainless steel thin film. Specifically, the gas barrier layer (20) may be manufactured by molding and / or processing a stainless steel thin film. The gas barrier layer (20) formed of stainless steel has relatively low thermal conductivity, which is effective in preventing or delaying heat diffusion to other cells during thermal runaway, and has relatively high toughness, which can suppress cracking of the pouch during use of the pouch-type battery. The stainless steel may include at least one element other than iron (Fe), for example, one selected from the group consisting of copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), silicon (Si), and zinc (Zn).

[0063] The thickness of the above gas barrier layer (20) may be 20 µm to 100 µm, specifically 30 µm to 90 µm, and more specifically 40 µm to 85 µm. When the above range is satisfied, it is preferable in that the ingress and egress of gas or moisture from outside the secondary battery can be appropriately blocked, and electrolyte leakage from inside the pouch-type battery case can be appropriately prevented. In addition, the formability and gas barrier performance can be improved during the molding of the cup portion.

[0064]

[0065] (3) Sealant layer

[0066] The sealant layer (30) is intended to completely seal the inside of the pouch-shaped battery case by mutually thermally bonding the sealing portion when the pouch-shaped battery case containing the electrode assembly inside is sealed. To this end, the sealant layer (30) may be formed of a material having excellent thermal bonding strength.

[0067] The sealant layer (30) may be formed of a material having insulating, corrosion-resistant, and sealing properties. Specifically, since the sealant layer (30) is in direct contact with the electrode assembly and / or electrolyte inside the pouch-type battery case, it may be formed of a material having insulating and corrosion-resistant properties. In addition, since the sealant layer (30) must completely seal the inside of the pouch-type battery case to block material movement between the inside and the outside, it may be formed of a material having high sealing properties (e.g., excellent thermal bonding strength). In order to secure such insulating, corrosion-resistant, and sealing properties, the sealant layer (30) may be formed of a polymer material.

[0068] The above sealant layer (30) may include one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, and Teflon, and specifically may include 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. More specifically, the sealant layer (30) may include at least one selected from polypropylene (PP), acid-modified polypropylene (PPa), and non-stretched polypropylene (CPP), and more specifically, from the gas barrier layer side, the sealant layer (30) may be formed of any one of a laminated structure of acid-modified polypropylene and polypropylene, a laminated structure of acid-modified polypropylene and non-stretched polypropylene, or a single layer of non-stretched polypropylene.

[0069] The amount of active agent present on the surface of the above sealant layer (30) is 1 mg / m 2 Less than, specifically, 0.8 mg / m 2 less than, more specifically, 0.5 mg / m 2 It may be less than. The present invention can maintain appropriate frictional force because a separate silicone release coating layer exists even when the lubricant is included in the above range, and since contamination of the mold is reduced due to the small amount of lubricant, the lubricant cleaning cycle can be extended, thereby improving processability.

[0070] The above sealant layer (30) may have a coefficient of friction of 0.05 to 0.30, specifically 0.1 to 0.2, and more specifically 0.12 to 0.18. When the above range is satisfied, the slipperiness of the sealant layer is appropriately improved, so that even if physical deformation occurs in the sealant layer during molding, the occurrence of defects such as cracks is reduced and the whitening phenomenon can be reduced.

[0071] The thickness of the sealant layer (30) may be 30 µm to 130 µm, specifically 40 µm to 120 µm, and more specifically 60 µm to 100 µm. When the thickness of the sealant layer satisfies the above range, there is an effect of securing the sealing strength of the sealing portion while also securing the formability of the pouch film laminate.

[0072] Meanwhile, the sealant layer (30) according to the present invention may have a composite film structure in which two or more materials are each formed to form layers. For example, the sealant layer (30) may have a multilayer structure. An adhesive layer and / or a skin layer may be disposed between each layer of the sealant layer (30) having a composite film structure. The adhesive layer and / or the skin layer may have thermal adhesiveness and thus may play a role in assisting adhesion between each layer of the sealant layer (30). For example, the adhesive layer and / or the skin layer may include a polypropylene-based resin, but is not limited thereto. In addition, the adhesive layer and / or the skin layer may be disposed between the sealant layer (30) and the gas barrier layer (20).

[0073]

[0074] (4) Silicone-based heteromorphic coating layer

[0075] According to one embodiment of the present invention, a silicone-based release coating layer (40) is coated on the sealant layer (30), and the thickness of the silicone-based release coating layer (40) is characterized by being 1 ㎛ or less, specifically 0.5 ㎛ or less, and more specifically 0.1 ㎛ or less.

[0076] When the thickness of the silicone-based release coating layer satisfies the above range, sealing strength can be secured due to the thin thickness. However, when the thickness of the silicone-based release coating layer exceeds 1 ㎛, the silicone-based polymer and polypropylene do not mix well at the interface during pouch sealing, resulting in a problem of reduced sealing strength.

[0077] The above silicone-based release coating layer (40) includes a silicone-based release agent, and the silicone-based release agent is characterized by being a crosslinked silicone-based polymer having a weight average molecular weight of less than 1,000,000 g / mol.

[0078] The silicone polymer is not particularly limited as long as it can impart slipperiness, but may be at least one selected from the group consisting of polydimethylsiloxane (PDMS), polysilane, polycarbosilane, polysilazane, and the like, and more specifically, may be polydimethylsiloxane (PDMS). When the silicone polymer is included in the silicone release coating layer, unlike when a lubricant is used, contamination of the mold is reduced, so that the cleaning cycle is extended, and thus the processability can be improved. In addition, the defect rate due to contamination can be reduced, so that the processability can be improved. Wrinkles may not occur during molding of the cup portion, and the maximum molding depth can be excellent.

[0079] The above silicone polymer is characterized by having a weight average molecular weight of less than 1,000,000 g / mol, specifically, the weight average molecular weight may be less than 900,000 g / mol, and more specifically, the weight average molecular weight may be less than 600,000 g / mol. When the weight average molecular weight of the silicone polymer is 1,000,000 g / mol or more, there is a problem that the viscosity is high and the coatability is reduced.

[0080] The weight average molecular weight may refer to a conversion value for standard polystyrene measured by gel permeation chromatography (GPC, Gel Permeation Chromatograph), and unless otherwise specified, the molecular weight may refer to the weight average molecular weight. For example, in the present invention, the weight average molecular weight is measured using the Agilent 1200 series, and the column used here may be the Agilent PL mixed B column, and the solvent may be tetrahydrofuran (THF, TETRAHYDROFURAN).

[0081] The above silicone-based release agent is characterized by the silicone-based polymer being crosslinked. If the silicone-based polymer is not crosslinked, the physical properties may be weakened, and the silicone may be transferred to the mold, thereby contaminating the mold.

[0082] The above silicone-based release coating layer may further include a polyolefin-based resin such as polyethylene (PE) and polypropylene (PP) in addition to a silicone-based polymer. The polyolefin-based resin may be included to advantageously maintain adhesion between the silicone-based release coating layer and the sealant layer of the pouch film laminate, and may have a melting point higher than that of the silicone-based polymer, thereby ensuring heat resistance.

[0083] The above silicone-based release coating layer (40) may contain polydimethylsiloxane (PDMS) in an amount of 80 wt% or more, specifically 85 wt% or more, and more specifically 90 wt% or more, based on the total weight of the silicone-based release coating layer. When the weight ratio of the polydimethylsiloxane (PDMS) satisfies the above range, when mixed with a crosslinking agent, an appropriate frictional force is generated due to the slipperiness of the polydimethylsiloxane (PDMS), thereby preventing a blocking phenomenon in which the films stick to each other during the manufacture of the pouch film laminate.

[0084] The above silicone-based release coating layer (40) can be formed by coating on the sealant layer (30). The coating method is not particularly limited, and known coating methods such as slot die, gravure coating, spin coating, spray coating, roll coating, curtain coating, extrusion, casting, screen printing, inkjet printing, chemical vapor deposition (CVD), or physical vapor deposition (PVD) can be used.

[0085]

[0086] The pouch film laminate according to the present invention as described above can be manufactured through a method for manufacturing a pouch film laminate known in the art. For example, the pouch film laminate according to the present invention can be manufactured through a method of attaching a substrate layer (10) to an upper surface of a gas barrier layer (20) using an adhesive, forming a sealant layer (30) on a lower surface of the gas barrier layer (20) through coextrusion or an adhesive layer, and coating a silicone-based release coating layer (40) on the lower surface of the sealant layer (30) through heat treatment, and can be manufactured through a method such as dry lamination or sandwich lamination. However, the method for manufacturing a pouch film laminate is not limited thereto.

[0087]

[0088] The thickness of the pouch film laminate according to the present invention may be 120 µm to 300 µm, specifically 130 µm to 280 µm, and more specifically 140 µm to 250 µm. When the thickness of the pouch film laminate satisfies the above range, the forming depth can be increased while minimizing the reduction in battery accommodation space and the deterioration of sealing durability due to the increase in the thickness of the pouch laminate.

[0089]

[0090] Pouch-type secondary battery

[0091] Next, a pouch-type secondary battery (200) according to the present invention will be described. Fig. 2 illustrates an exploded and assembled view of a pouch-type secondary battery (200) according to the present invention.

[0092] As illustrated in FIG. 2, a pouch-type secondary battery (200) according to the present invention may include a pouch-type battery case (210) manufactured by molding the aforementioned pouch film laminate, and an electrode assembly (260) housed in the pouch-type battery case (210). Specifically, the pouch-type secondary battery (200) according to the present invention may include a pouch-type battery case (210), an electrode assembly (260), an electrode lead (280), an insulator (290), and an electrolyte (not shown).

[0093] Hereinafter, each component of the pouch-type secondary battery according to the present invention will be described in more detail with reference to FIG. 2.

[0094]

[0095] (1) Pouch-type battery case

[0096] A pouch-shaped battery case (210) can be manufactured by molding the pouch film laminate according to the present invention described above. The pouch-shaped battery case (210) can accommodate an electrode assembly (260) inside. Since the detailed configuration and properties of the pouch film laminate are the same as those described above, a detailed description thereof will be omitted.

[0097] The pouch film laminate can be drawn and stretched by a punch or the like to manufacture a pouch-shaped battery case (210). As a result, the pouch-shaped battery case (210) can include a cup portion (222) and a receiving portion (224). The receiving portion (224) is a place for receiving an electrode assembly, and can mean a receiving space formed in the shape of a pocket on the inside of the cup portion (222) as the cup portion (222) is formed.

[0098] According to one embodiment of the present invention, a pouch-type battery case (210) may include a first case (220) and a second case (230) as illustrated in FIG. 3. The first case (220) includes a receiving portion (224) capable of receiving an electrode assembly (260), and the second case (230) may cover the receiving portion (224) from above to prevent the electrode assembly (260) from being separated from the outside of the battery case (210). The first case (220) and the second case (230) may be manufactured such that one side thereof is connected to each other as illustrated in FIG. 3, but are not limited thereto and may be manufactured in various ways, such as being manufactured separately and separated from each other.

[0099]

[0100] According to another embodiment of the present invention, when forming a cup portion on a pouch film laminate, two symmetrical cup portions (222, 232) can be drawn and formed adjacent to each other on one pouch film laminate. In this case, cup portions (222, 232) can be formed in the first case (220) and the second case (230) respectively, as illustrated in FIG. 3. After the electrode assembly (260) is accommodated in the receiving portion (224) provided in the cup portion (222) of the first case (220), the bridge portion (240) formed between the two cup portions (222, 232) can be folded so that the two cup portions (222, 232) face each other. In this case, the cup portion (232) of the second case (230) can accommodate the electrode assembly (260) from above. Accordingly, since two cup portions (222, 232) accommodate one electrode assembly (260), an electrode assembly (260) having a thicker thickness can be accommodated than when there is only one cup portion (222). In addition, since one corner of the secondary battery (200) is formed by folding the pouch-type battery case (210), the number of corners to be sealed can be reduced when performing a sealing process later. Accordingly, the process speed of the pouch-type secondary battery (200) can be improved, and the number of sealing processes can be reduced.

[0101] The pouch-type battery case (210) can be sealed while housing the electrode assembly (260) so that a portion of the electrode lead (280) described later, i.e., a terminal portion, is exposed. Specifically, when the electrode lead (280) is connected to the electrode tab (270) of the electrode assembly (260) and an insulating portion (290) is formed on a portion of the electrode lead (280), the electrode assembly (260) can be housed in a receiving portion (224) provided in a cup portion (222) of the first case (220), and the second case (230) can cover the receiving portion (224) from above. Subsequently, an electrolyte can be injected into the interior of the receiving portion (224), and the sealing portions (250) formed on the edges of the first case (220) and the second case (230) can be sealed.

[0102] The sealing portion (250) can perform a function of sealing the receiving portion (224). Specifically, the sealing portion (250) can seal the receiving portion (224) while being formed along the edge of the receiving portion (224). The temperature at which the sealing portion (250) is sealed can be 180°C to 250°C, specifically 200°C to 250°C, and more specifically 210°C to 240°C. When the sealing temperature satisfies the above numerical range, the pouch-type battery case (210) can secure sufficient sealing strength through thermal bonding.

[0103]

[0104] (2) Electrode assembly

[0105] The electrode assembly (260) can be inserted into a pouch-type battery case (210) and sealed by the pouch-type battery case (210) after electrolyte injection.

[0106] The electrode assembly (260) may be formed by sequentially stacking an anode, a separator, and a cathode. Specifically, the electrode assembly (260) may include two types of electrodes, an anode and a cathode, and a separator interposed between the electrodes to mutually insulate the electrodes.

[0107] The positive and negative electrodes may each have a structure in which an active material slurry is applied to an electrode current collector in the form of a metal foil or metal mesh containing aluminum and copper, respectively. The slurry is typically formed by stirring granular active materials, auxiliary conductors, binders, and conductive agents with the addition of a solvent. The solvent can be removed in a subsequent process.

[0108] A slurry containing an electrode active material, a binder, and / or a conductive material is applied to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode, and these are laminated on both sides of a separator, thereby manufacturing an electrode assembly (260) in a predetermined shape. The types of electrode assembly (260) may include, but are not limited to, a stack type, a jelly roll type, a stack and folding type, etc.

[0109] The electrode assembly (260) may include an electrode tab (270).

[0110] The electrode tabs (270) are respectively connected to the positive and negative electrodes of the electrode assembly (260), and may protrude outward from the electrode assembly (260) to serve as a path for electrons to move between the inside and the outside of the electrode assembly (260). The electrode current collector included in the electrode assembly (260) may be composed of a portion where an electrode active material is applied and a terminal portion where the electrode active material is not applied, i.e., a non-coated portion. The electrode tabs (270) may be formed by cutting the non-coated portion or by connecting a separate conductive member to the non-coated portion by ultrasonic welding, etc. As illustrated in FIG. 2, the electrode tabs (270) may protrude in different directions of the electrode assembly (260), but are not limited thereto, and may be formed to protrude in various directions, such as protruding in parallel in the same direction from one side.

[0111]

[0112] (3) Electrode lead

[0113] The electrode lead (280) can supply electricity to the outside of the secondary battery (200). The electrode lead (280) can be connected to the electrode tab (270) of the electrode assembly (260) by spot welding, etc.

[0114] The electrode lead (280) is connected to the electrode assembly (260) and may protrude to the outside of the pouch-type battery case (210) via the sealing portion (250). Specifically, one end of the electrode lead (280) is connected to the electrode assembly (260), particularly to the electrode tab (270), and the other end of the electrode lead (280) may protrude to the outside of the pouch-type battery case (210).

[0115] The electrode lead (280) may include a positive lead (282) having one end connected to the positive tab (272) and extending in the protruding direction of the positive tab (272), and a negative lead (284) having one end connected to the negative tab (274) and extending in the protruding direction of the negative tab (274). Both the positive lead (282) and the negative lead (284) may have other ends protruding outward from the battery case (210). Accordingly, electricity generated inside the electrode assembly (260) may be supplied to the outside. In addition, since the positive tab (272) and the negative tab (274) are formed to protrude in various directions, the positive lead (282) and the negative lead (284) may also extend in various directions, respectively. The positive lead (282) and the negative lead (284) may be made of different materials. That is, the positive electrode lead (282) may be made of the same aluminum (Al) material as the positive electrode collector, and the negative electrode lead (284) may be made of the same copper (Cu) material as the negative electrode collector or a copper material coated with nickel (Ni). A portion of the electrode lead (280) protruding outside the battery case (210) may serve as a terminal portion and be electrically connected to an external terminal.

[0116]

[0117] (4) Insulation

[0118] The insulating portion (290) prevents electricity generated from the electrode assembly (260) from flowing to the battery case (210) through the electrode lead (280) and can maintain the sealing of the battery case (210). To this end, the insulating portion (290) may be formed of a non-conductive material that does not conduct electricity well. In general, the insulating portion (290) is often formed of an insulating tape or film that is easy to attach to the electrode lead (280) and has a relatively thin thickness, but is not limited thereto, and any material capable of insulating the electrode lead (280) may be used.

[0119] The insulating portion (290) may be arranged to surround the outer circumference of the electrode lead (280). Specifically, at least a portion of the electrode lead (280) may be surrounded by the insulating portion (290). In this case, the insulating portion (290) may be arranged between the electrode lead (280) and the pouch-type battery case (210). The insulating portion (290) may be positioned limited to the sealing portion (250) where the first case (220) and the second case (230) of the pouch-type battery case (210) are thermally fused, and may adhere the electrode lead (280) to the battery case (210).

[0120]

[0121] (5) Electrolyte

[0122] The pouch-type secondary battery (200) according to the present invention may further include an electrolyte (not shown) that is poured into the pouch-type battery case (210). The electrolyte is for moving lithium ions generated by an electrochemical reaction of an electrode during charging / discharging of the secondary battery (200), and may include a non-aqueous organic electrolyte that is a mixture of a lithium salt and an organic solvent, or a polymer using a polymer electrolyte. Furthermore, the electrolyte may include a solid electrolyte of a sulfide type, an oxide type, or a polymer type, and such a solid electrolyte may have flexibility that is easily deformed by an external force.

[0123]

[0124] Hereinafter, the present invention will be described in more detail through specific examples. However, the following examples are merely illustrative and serve to aid understanding of the present invention and do not limit its scope. It will be apparent to those skilled in the art that various modifications and variations are possible within the scope and technical spirit of this disclosure, and such modifications and variations are naturally within the scope of the appended claims.

[0125]

[0126] Examples and Comparative Examples

[0127] Example 1: Preparation of pouch film laminate

[0128] A sealant layer comprising sequentially laminated acid-modified polypropylene (PPa) and polypropylene (PP) with a total thickness of 80 μm was manufactured, and a silicone-based release coating layer consisting solely of cross-linked polydimethylsiloxane (PDMS) having a weight average molecular weight of 590,000 g / mol was coated on the sealant layer to a thickness of 0.1 μm.

[0129] After that, a second adhesive film, a 25-μm-thick nylon film, a first adhesive film, and a 12-μm-thick polyethylene terephthalate (PET) film were sequentially laminated on one side of an aluminum alloy film having a thickness of 60 μm, and a sealant layer coated with the silicone-based release coating layer was sequentially laminated on the other side of the aluminum alloy film.

[0130] As a result, a pouch film laminate having a structure in which the silicone-based release coating layer / sealant layer (polypropylene / acid-modified polypropylene) / aluminum alloy thin film / second adhesive film / nylon film / first adhesive film / polyethylene terephthalate film are sequentially laminated as described above was manufactured.

[0131]

[0132] Example 2: Preparation of pouch film laminate

[0133] A pouch film laminate was manufactured in the same manner as in Example 1, except that the silicone-based heteromorphic coating layer was coated to a thickness of 0.5 μm.

[0134]

[0135] Example 3: Preparation of pouch film laminate

[0136] A pouch film laminate was manufactured in the same manner as in Example 1, except that the silicone-based heterogeneous coating layer was coated to a thickness of 1.0 μm.

[0137]

[0138] Example 4: Preparation of pouch film laminate

[0139] A pouch film laminate was prepared in the same manner as in Example 1, except that cross-linked polydimethylsiloxane (PDMS) having a weight average molecular weight of 800,000 g / mol was used.

[0140]

[0141] Example 5: Preparation of pouch film laminate

[0142] A pouch film laminate was manufactured in the same manner as in Example 1, except that the silicone-based release coating layer was manufactured by mixing 80 wt% of polydimethylsiloxane (PDMS) and 20 wt% of polypropylene (PP) based on the total weight of the silicone-based release coating layer.

[0143]

[0144] Example 6: Preparation of pouch film laminate

[0145] A pouch film laminate was manufactured in the same manner as in Example 1, except that the silicone-based release coating layer was manufactured by mixing 70 wt% of polydimethylsiloxane (PDMS) and 30 wt% of polypropylene (PP) based on the total weight of the silicone-based release coating layer.

[0146]

[0147] Comparative Example 1: Manufacturing of a pouch film laminate

[0148] A pouch film laminate was manufactured in the same manner as in Example 1, except that the silicone-based heteromorphic coating layer was coated to a thickness of 2.0 μm.

[0149]

[0150] Comparative Example 2: Manufacturing of a pouch film laminate

[0151] Without forming a separate silicone-based release coating layer, the amount of lubricant on the surface of the sealant layer is 4 mg / m 2 A pouch film laminate was manufactured in the same manner as in Example 1, except that an activator (Erucamide) was applied.

[0152]

[0153] Comparative Example 3: Manufacturing of a pouch film laminate

[0154] Without forming a separate silicone-based release coating layer, the amount of lubricant on the surface of the sealant layer is 26 mg / m 2 A pouch film laminate was manufactured in the same manner as in Example 1, except that an activator (Erucamide) was applied.

[0155]

[0156] Comparative Example 4: Manufacturing of a pouch film laminate

[0157] A pouch film laminate was prepared in the same manner as in Example 1, except that cross-linked polydimethylsiloxane (PDMS) having a weight average molecular weight of 1,100,000 g / mol was used.

[0158] However, in this case, the viscosity of the silicone-based release agent became excessively high due to the high weight average molecular weight, making it impossible to form a silicone-based release coating layer.

[0159]

[0160] Experimental Example 1: Friction Coefficient Measurement

[0161] The coefficient of friction of each pouch film laminate manufactured according to Examples 1 to 6 and Comparative Examples 1 to 3 was measured.

[0162] As a method of measuring the coefficient of friction, a sled metal having a size of 130 mm (MD direction) x 65 mm (TD direction) and a weight of 200 g was brought into contact with a silicone-based release coating layer of a pouch film laminate having a size of 300 mm (MD direction) x 200 mm (TD direction).

[0163] In detail, the sled metal was moved 100 mm over the sealant layer at a speed of 100 mm / min, and the coefficient of friction was measured five times in the range of 20 mm to 80 mm, taking the average value.

[0164] The measurement results are shown in [Table 1] below.

[0165]

[0166] Experimental Example 2: Evaluation of Formability of Pouch Film Laminate

[0167] (1) Evaluation of forming depth

[0168] The formability of each pouch film laminate manufactured according to Examples 1 to 6 and Comparative Examples 1 to 3 was evaluated.

[0169] As a method for evaluating the formability of a pouch film laminate, the pouch film laminate was cut into equal sizes of 300 mm (MD direction) x 400 mm (TD direction), and then the maximum forming depth without cracks was recorded while changing the forming depth in a battery case forming device having two forming parts of sizes of 61 mm (MD direction) x 159 mm (TD direction). Here, the punch and the forming part of the battery case forming device were filleted at the corners and edges, and the corner of the punch had a curvature of 2 mm and the corner of the edge had a curvature of 0.5 mm, and the corner of the forming part had a curvature of 2.5 mm and the corner of the edge had a curvature of 1 mm. In addition, the clearance between the punch and the forming part was 0.5 mm.

[0170] The measured forming depth is listed in [Table 1] below.

[0171]

[0172] (2) Evaluation of wrinkle occurrence

[0173] During the above molding depth evaluation, if wrinkles occurred in the cup portion of the pouch film laminate at the maximum molding depth when molding the pouch film with an uncontaminated molding device, it was evaluated as O, and if no wrinkles occurred, it was evaluated as X.

[0174] The occurrence of wrinkles is shown in [Table 1] below.

[0175]

[0176] Experimental Example 3: Measurement of the cleaning cycle of the active agent during pouch film laminate molding.

[0177] When molding each pouch film laminate manufactured according to Examples 1 to 6 and Comparative Examples 1 to 3, the cleaning cycle of the active agent was measured.

[0178] In detail, when continuously producing a pouch film laminate in which a cup portion of the maximum forming depth is formed, the cleaning cycle of the lubricant was measured based on the maximum number of strokes without wrinkles occurring.

[0179] The measurement results are shown in [Table 1] below.

[0180]

[0181] Experimental Example 4: Measurement of Sealing Strength

[0182] The sealing strength of each pouch film laminate manufactured according to Examples 1 to 6 and Comparative Examples 1 to 3 was measured.

[0183] As a method for measuring the sealing strength of a pouch film laminate, the pouch film laminate was cut into 266 mm wide and 200 mm long pieces, folded in half to a size of 133 mm wide × 200 mm so that the silicone-based release coating layer was in contact, and then the long side (200 mm) end was sealed for 1.6 seconds, 3 seconds, or 5 seconds, respectively, under conditions of a seal bar area of ​​200 mm × 8 mm, 200°C, and 0.1 MPa, thereby manufacturing a pouch-type battery case in which a sealing portion was formed, and the sealing strength of the pouch-type battery case was measured according to each sealing time.

[0184] Specifically, the sealing strength was calculated from the maximum value of the tensile strength measured by cutting the sealing portion formed in the pouch-shaped battery case at 15 mm intervals and pulling it in a 180° direction at a speed of 5 mm / min at room temperature using a UTM.

[0185] Based on the calculated sealing strength, if the measured sealing strength was 10 kgf or more, it was evaluated as O, and if it was less than 10 kgf, it was evaluated as X.

[0186] The evaluation results are shown in [Table 1] below.

[0187]

[0188] Friction coefficientForming depth [mm]Whether wrinkles occurLubricant cleaning cycle [other]Sealing strengthExample 10.28.0X5000OExample 20.18.0X6000OExample 30.138.0X8000OExample 40.28.0X5000OExample 50.257.5X5000OExample 60.357.0X5000OComparative example 10.108.0X10,000XComparative example 20.46.0X5000OComparative example 30.05Less than8.0O500OComparative example 4Silicone-based release coating layer cannot be formed

[0189] Referring to the above [Table 1], it can be confirmed that examples 1 to 6 have lower coefficients of friction and better formability than comparative examples 1 to 3.

[0190] In addition, in the case of Examples 1 to 6, it can be confirmed that the cleaning cycle of the lubricant is longer than that of Comparative Examples 2 to 3 in which the lubricant is applied to the surface of the sealant layer, and that no wrinkles occur during the formation of the pouch film laminate.

[0191]

[0192] [Explanation of symbols]

[0193] 1: Pouch film laminate

[0194] 10: Substrate layer

[0195] 12: Polyethylene terephthalate film

[0196] 14: Nylon film

[0197] 20: Gas barrier layer

[0198] 30: Sealant layer

[0199] 40: Silicone-based release coating layer

[0200] 200: Pouch-type secondary battery

[0201] 210: Pouch-type case

[0202] 220: Case 1

[0203] 222: Cup Department

[0204] 224: Reception area

[0205] 230: Case 2

[0206] 232: Cup

[0207] 240: Bridge section

[0208] 250: Sealing part

[0209] 260: Electrode assembly

[0210] 270: Electrode tab

[0211] 272: Positive tab

[0212] 274: Negative tab

[0213] 280: Electrode lead

[0214] 282: Positive lead

[0215] 284: Negative lead

[0216] 290: Insulation

Claims

1. A pouch film laminate comprising a sequentially laminated substrate layer, a gas barrier layer, and a sealant layer, The above pouch film laminate includes a silicone-based release coating layer coated on the sealant layer, The thickness of the above silicone-based heterogeneous coating layer is 1㎛ or less, The above silicone-based release coating layer includes a silicone-based release agent, The above silicone-based release agent is a pouch film laminate in which a silicone-based polymer having a weight average molecular weight of less than 1,000,000 g / mol is crosslinked.

2. In claim 1, A pouch film laminate wherein the above silicone polymer is at least one selected from the group consisting of polydimethylsiloxane (PDMS), polysilane, polycarbosilane, polysilazane, etc.

3. In claim 1, The above silicone-based release coating layer comprises a polyolefin-based resin, A pouch film laminate in which the silicone-based release coating layer contains the silicone-based release agent in an amount of 80% by weight or more relative to the total weight of the silicone-based release coating layer.

4. In claim 1, The amount of active agent present on the surface of the sealant layer is 1 mg / m 2 A pouch film laminate having a thickness of less than 100 μm.

5. In claim 1, A pouch film laminate having a coefficient of friction of the sealant layer of 0.05 to 0.

30.

6. In claim 1, A pouch film laminate wherein the above-mentioned substrate layer comprises at least one of polyethylene terephthalate (PET) and nylon.

7. In claim 1, A pouch film laminate having a thickness of the above-mentioned substrate layer of 5 ㎛ to 70 ㎛.

8. In claim 1, A pouch film laminate in which the gas barrier layer comprises at least one metal selected from the group consisting of aluminum (Al), copper (Cu), stainless steel (SUS), nickel (Ni), titanium (Ti), and invar.

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

10. In claim 1, A pouch film laminate, wherein the sealant layer comprises at least one selected from polypropylene (PP), acid-modified polypropylene (PPa), and non-stretched polypropylene (CPP).

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

12. In claim 1, A pouch film laminate having a thickness of 120 ㎛ to 300 ㎛.

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

14. A pouch-type secondary battery including the battery case of claim 13.

Images