Sealing tape for all-solid-state rechargeable batteries, and all-solid-state rechargeable battery including same

Abstract

The present invention relates to a sealing tape for all-solid-state rechargeable batteries and an all-solid-state rechargeable battery including same, the sealing tape including a substrate and an adhesive layer located on one surface of the substrate, and having a creep value of at least 500 µm at 45°C and a shear strength of at least 0.98 kgf / cm2 at 45°C.

Description

Sealing tape for all-solid-state secondary batteries and all-solid-state secondary batteries containing the same

[0001] The present invention relates to a sealing tape for an all-solid-state secondary battery, and an all-solid-state secondary battery including the same.

[0002] Lithium secondary batteries, which boast high energy density and portability, are primarily used as power sources for mobile information terminals such as mobile phones, laptops, and smartphones. Recently, active research is underway to utilize high-energy-density lithium secondary batteries as power sources for hybrid and electric vehicles, or as power storage devices.

[0003] Commercially available lithium secondary batteries use electrolytes containing flammable organic solvents, posing safety concerns that can lead to explosions or fires in the event of collisions, penetrations, or other problems. Therefore, semi-solid or all-solid-state batteries, which avoid the use of electrolytes, are being proposed. All-solid-state batteries are comprised entirely of solid materials, specifically those that utilize solid electrolytes. These all-solid-state batteries are safe, eliminating the risk of electrolyte leakage and explosion, and offer the advantage of being easy to manufacture in thin forms.

[0004] One embodiment provides a sealing tape for an all-solid-state secondary battery that has high shear strength at room temperature and high strain characteristics at 45°C, which is close to the charge / discharge conditions of a battery, thereby maintaining high pressure in the stacking direction of the battery under normal conditions and exhibiting a high strain rate during charge / discharge, thereby maintaining uniform pressure on the battery.

[0005] Another embodiment provides an all-solid-state secondary battery including the sealing tape for the all-solid-state secondary battery.

[0006] In one embodiment, a sealing tape for an all-solid-state secondary battery comprising a substrate and an adhesive layer positioned on one surface of the substrate, wherein the creep value at 45°C is 500 μm or more and the shear strength at 45°C is 0.98 kgf / cm 2 Provides a sealing tape for an all-solid-state secondary battery.

[0007] In another embodiment, an all-solid-state secondary battery is provided, comprising a battery assembly including a positive electrode, a solid electrolyte layer, and a negative electrode, and the aforementioned sealing tape attached to at least a portion of an exterior of the battery assembly.

[0008] According to an embodiment, a sealing tape for an all-solid-state secondary battery has high shear strength at room temperature and can exhibit high deformation characteristics at 45°C, which is close to the charge / discharge conditions of the battery. Therefore, an all-solid-state secondary battery using this as a sealing tape can maintain high pressure in normal times and receive uniform pressure on all sides of the battery during charge / discharge or at high temperature conditions, thereby resolving the problem of localized stress concentration, thereby improving life characteristics and reliability, and at the same time, improving Coulombic efficiency.

[0009] Figure 1 is a schematic diagram showing a sealing tape attached to an all-solid-state secondary battery according to one embodiment.

[0010] Figure 2 is a top view of an all-solid-state secondary battery with a sealing tape attached according to one embodiment.

[0011] Figures 3 and 4 are cross-sectional views schematically showing an all-solid-state secondary battery according to one embodiment.

[0012] Figure 5 is a drawing for explaining a shear strength evaluation method.

[0013] Figure 6 is a drawing for explaining a creep evaluation method.

[0014] Below, specific implementation examples are described in detail to facilitate their implementation by those skilled in the art. However, the present invention may be implemented in various different forms and is not limited to the implementation examples described herein.

[0015] The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

[0016] “Combination of these” means a mixture, laminate, composite, copolymer, alloy, blend, reaction product, etc. of the components.

[0017] It should be understood that terms such as "include," "comprise," or "have" are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0018] To clearly illustrate various layers and regions in the drawings, their thicknesses are enlarged, and similar parts are designated by the same drawing reference numerals throughout the specification. When an element such as a layer, film, region, or plate is said to be "over" or "on" another element, this includes not only the case where it is "directly over" the other element, but also the case where there are other elements in between. Conversely, when an element is said to be "directly over" another element, it means that there are no other elements in between.

[0019] “Layer” includes not only shapes formed on the entire surface when observed in a plan view, but also shapes formed on some surfaces.

[0020] “Or” is not interpreted as exclusive, for example, “A or B” is interpreted as including A, B, A+B, etc.

[0021] Generally, all-solid-state secondary batteries cannot be manufactured or used in an exposed atmosphere due to the nature of their solid electrolytes. Therefore, isolation from the atmosphere is necessary. To achieve this, the stacked structure of the all-solid-state secondary battery is injected into an external body or compressed into a laminate film. This process applies pressure to the all-solid-state secondary battery, and the stress transferred to the solid electrolyte can cause cracks and short circuits. Furthermore, if the stress transferred to the solid electrolyte accumulates, there is a risk that it will break.

[0022] Therefore, when injecting the laminate into an outer packaging material or pouch for an all-solid-state secondary battery, the sealing tape surrounding the laminate must have high shear strength to prevent separation of the cell structure of the battery. Simultaneously, the sealing tape must have excellent creep deformation characteristics during battery charging and discharging, so that it can disperse the stress applied to the solid electrolyte and apply a uniform surface pressure.

[0023] Meanwhile, the Coulombic efficiency of all-solid-state secondary batteries may decrease due to changes in the thickness of the negative electrode active material layer during charge and discharge. When the thickness of the negative electrode active material layer increases during charging, stress is added to the solid electrolyte layer and the negative electrode current collector, which may cause an electrode reaction in that state. In a stressed state, ion conduction paths and electron conduction paths are easily secured even if the contact between the solid electrolyte layer and the negative electrode current collector, that is, the solids, is not in a good state. Conversely, when the thickness of the negative electrode active material layer decreases during discharge, the stress is relieved, which deteriorates the contact between the solids. As a result, the ion conduction paths and electron conduction paths of the all-solid-state secondary battery are easily interrupted, which may result in a decrease in Coulombic efficiency.

[0024] Therefore, a sealing tape is required that can prevent the deterioration of the contact state between solids by improving the tracking ability of the negative electrode current collector to the change in the thickness of the negative electrode active material layer due to charging.

[0025] To address the above-mentioned problem, the inventors focused on the tracking properties of the negative electrode current collector. Specifically, they studied how to improve the tracking properties of the negative electrode current collector to variations in the thickness of the negative electrode active material layer due to charge / discharge cycles, thereby suppressing the deterioration of the contact between solids. This led to the present invention.

[0026]

[0027] sealing tape

[0028] In one embodiment, a sealing tape for an all-solid-state secondary battery is provided, which includes a substrate and an adhesive layer positioned on one surface of the substrate, wherein the sealing tape has a creep value at 45°C of 500 μm or more and a shear strength at 45°C of 0.98 kgf / cm. 2 It is characterized by the following:

[0029] According to an embodiment, the sealing tape (600) for an all-solid-state secondary battery has relatively relaxed shear strength and excellent creep deformation characteristics under charge and discharge conditions, so that an all-solid-state secondary battery including the same can distribute stress applied to a cell structure and apply uniform pressure even when the thickness of a negative electrode active material layer changes according to charge and discharge. Accordingly, excellent contact between solids within the battery is achieved, thereby ensuring excellent ion conduction and electron conduction, and thus increasing coulombic efficiency. In addition, since the stress applied to the cell structure is distributed, damage to a solid electrolyte within the all-solid-state battery can be prevented, and the lifespan of the all-solid-state battery can be improved.

[0030] According to one embodiment, a sealing tape for an all-solid-state secondary battery has a creep value at 45°C of 500 μm or more, for example, 450 μm or more, 400 μm or more, or 350 μm or more, for example, 500 μm to 1000 μm, or 500 μm to 800 μm, but is not limited thereto. Creep refers to the distance that a tape with a width of 1 cm moves when it is adhered to glass and pulled at a speed of 10 μm / s with a force of 1000 gf for 5 minutes, and can be specifically measured by the same method as in Evaluation 2 below. The creep can be said to be a measured value when the thickness of the tape is in the range of 10 μm to 100 μm (for example, 30 μm or 35 μm) and the thickness of the adhesive layer is 5 μm to 50 μm (for example, 5 μm or 10 μm). A higher creep value indicates a higher tape strain, flexibility, or elastic modulus. According to one embodiment, a sealing tape exhibits a creep value of 500 μm or more at 45°C, which is close to the operating conditions of an all-solid-state secondary battery. This allows the tape to flexibly expand and contract in response to changes in battery thickness due to charge and discharge, thereby effectively performing its stress-relieving function.

[0031] And the above sealing tape has a shear strength of 0.98 kgf / cm at 45℃. 2 is ideal, for example, 0.95 kgf / cm 2 Above, 0.93 kgf / cm 2 Above, 0.90 kgf / cm 2 or 0.85 kgf / cm 2 It can be more than 0.98 kgf / cm, for example. 2 2 kgf / cm 2 , or 0.98 kgf / cm 2 1.5 kgf / cm 2It can be, but is not limited to these. Shear strength refers to the force applied when pulling a tape of (1 in) x (1 in) size at a speed of 12.5 mm / min, and can be specifically measured by the method of Evaluation 1 below. Similarly, shear strength can be said to be a measurement value when the thickness of the tape is in the range of 10 ㎛ to 100 ㎛ (e.g., 30 ㎛ or 35 ㎛) and the thickness of the adhesive layer is 5 ㎛ to 50 ㎛ (e.g., 5 ㎛ or 10 ㎛). The higher the shear strength, the better it maintains its shape or adhesive force without breaking or breaking even at a high shear force. According to one embodiment, the sealing tape has a shear strength of 0.98 kgf / cm at 45℃. 2 By implementing the above shear strength, the volume of the all-solid-state secondary battery expands during charging and discharging, and even when a shear force is applied to the sealing tape, it can maintain excellent adhesive strength without being torn or damaged.

[0032] A sealing tape according to one embodiment simultaneously satisfies the creep value and shear strength within the above range at 45°C, thereby flexibly deforming in accordance with changes in the thickness of an all-solid-state secondary battery during charging and discharging, thereby performing a stress-relieving function, and at the same time, maintaining a solid shape without being broken by shear force. Accordingly, an all-solid-state secondary battery finished with the sealing tape can receive uniform pressure on all surfaces in the stacking direction even when repeatedly charged and discharged, thereby resolving the problem of localized stress concentration, and ultimately improving overall performance such as coulombic efficiency and life characteristics.

[0033] In addition, the sealing tape may have a ratio of a creep (㎛) value to an adhesive layer thickness (㎛) at 45°C of 50 or more, for example, 60 or more, 70 or more, 80 or more, or 85 or more, for example, 50 to 200, or 50 to 100, but is not limited thereto. Since the sealing tape has a creep value for a thickness in the above range at 45°C, even if the volume of the all-solid-state secondary battery expands during charging and discharging, the sealing tape can flexibly withstand the expansion and the cell structure within the battery can be formed integrally.

[0034] The above sealing tape may have a creep value of 100㎛ or less at room temperature of 25℃, for example, 90㎛ or less, 85㎛ or less, or 80㎛ or less, and may be 30㎛ to 100㎛, or 50㎛ to 80㎛, but is not limited thereto. When the sealing tape satisfies the creep value of the above range at room temperature, it is not easily deformed at room temperature and can maintain a strong adhesive force, so that the pressed battery shape can be well maintained when the all-solid-state secondary battery is stored or moved at room temperature rather than while in operation.

[0035] In addition, the above sealing tape has a shear strength of 2.0 kgf / cm at 25℃. 2 It can be more than 2.5 kgf / cm, for example. 2 Above, 3.0 kgf / cm 2 or more than 3.5 kgf / cm 2 It can be more than 2.5 kgf / cm 2 8 kgf / cm 2 , or 2.5 kgf / cm 2 5 kgf / cm 2 However, the present invention is not limited thereto. If the sealing tape exhibits a shear strength within the above range at room temperature, it can maintain a solid shape, thereby ensuring that the solid-state secondary battery is well maintained in a pressurized state.

[0036] In addition, the sealing tape may have a creep value ratio to the adhesive layer thickness at 25°C of 15 or less, for example, 15 or less, 13 or less, or 11 or less, or 3 to 10 or 5 to 10, but is not limited thereto. When the sealing tape satisfies the creep value ratio to the thickness within the above range at room temperature, an appropriate shear strain can be implemented to firmly maintain the all-solid-state secondary battery in a pressurized state.

[0037] The above sealing tape may have an adhesive strength of about 300 gf / mm or more at 25°C, for example, 300 gf / mm to 800 gf / mm, 300 gf / mm to 500 gf / mm, or 350 gf / mm to 450 gf / mm. The adhesive strength may refer to a force required to peel in a 180° direction, and may be specifically measured by a method such as Evaluation 3 below. When the sealing tape implements an adhesive strength in the above range at room temperature, it can sufficiently firmly hold a pressurized all-solid-state secondary battery so as not to be separated.

[0038] According to one embodiment, when the sealing tape satisfies the creep value, shear strength, and creep ratio for thickness in the above range at 25°C, the cell structure within the battery can be integrated without separation during the manufacture, storage, and transportation of the all-solid-state battery, and deformation of the battery can be prevented, thereby improving the reliability of the battery.

[0039] The thickness of the sealing tape according to one embodiment may be 10 μm to 100 μm, for example, 15 μm to 100 μm, 20 μm to 100 μm, 25 μm to 100 μm, 30 μm to 100 μm, 10 μm to 95 μm, 10 μm to 90 μm, 10 μm to 85 μm, or 10 μm to 80 μm, but is not limited thereto. When the sealing tape has the above thickness range, it can implement appropriate physical properties such as appropriate shear strength, and is thus suitable for application as a finishing tape for an all-solid-state battery.

[0040] (write)

[0041] The substrate of the sealing tape may have a thickness of 5 μm to 50 μm, for example, 10 μm to 50 μm, 15 μm to 50 μm, 20 μm to 50 μm, 5 μm to 40 μm, or 5 μm to 30 μm, but is not limited thereto. When the thickness of the substrate satisfies the above range, appropriate physical properties such as shear strength can be realized.

[0042] The substrate may include, for example, polyethylene terephthalate, polyethylene, polypropylene, polyamide, polyimide, polyethylene naphthalate, polyacrylonitrile, poly(meth)acrylate, polymethyl(meth)acrylate, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl chloride, polyurethane, epoxy resin, nylon resin, acrylic resin, polystyrene, polyethylene oxide, polyvinyl alcohol, silicone resin, styrene-butadiene-rubber, acrylonitrile-butadiene-rubber, hydrogenated nitrile-butadiene-rubber, copolymers thereof, or mixtures thereof. For example, the substrate may be a polyethylene terephthalate (PET) film, a urethane film, an acrylic film, an epoxy film, an EVA film, and an example thereof may be, but is not limited to, a polyethylene terephthalate film.

[0043] (Adhesive layer)

[0044] The adhesive layer of the sealing tape may have a thickness of 5 μm to 50 μm, for example, 10 μm to 50 μm, 15 μm to 50 μm, 20 μm to 50 μm, 5 μm to 40 μm, or 5 μm to 30 μm, but is not limited thereto. When the thickness of the adhesive layer satisfies the above range, it can exhibit excellent adhesive strength while also exhibiting appropriate physical properties such as shear strength and creep value.

[0045] The adhesive layer comprises an adhesive polymer, and the molecular weight of the adhesive polymer may be 800,000 g / mol to 5,000,000 g / mol, for example, 800,000 g / mol to 4,000,000 g / mol, 800,000 g / mol to 3,500,000 g / mol, for example, 1,000,000 g / mol to 5,000,000 g / mol, 1,000,000 g / mol to 4,500,000 g / mol, 1,500,000 g / mol to 4,500,000 g / mol, 1,700,000 g / mol to 5,000,000 g / mol, 2,000,000 g / mol to 5,000,000 g / mol, 1,500,000 g / mol to 4,500,000 g / mol, or 1,500,000 g / mol to 4,000,000 g / mol, but is not limited thereto. Here, the molecular weight may be a value measured using gel permeation chromatography (GPC). When the adhesive polymer satisfies the molecular weight within the above range, a sealing tape containing the adhesive polymer exhibits high adhesive strength and shear strength at room temperature, and can exhibit excellent deformation at a high temperature of 45°C.

[0046] The glass transition temperature (T) of the above adhesive polymer g) can be -50℃ to -5℃, for example, -45℃ to -5℃, -40℃ to -5℃, 35℃ to -5℃, 30℃ to -5℃, -40℃ to -10℃, or -40℃ to -15℃, but is not limited thereto. Here, the glass transition temperature can be measured using DSC (TA Instrument) equipment. When the glass transition temperature of the adhesive polymer satisfies the above range, the sealing tape containing it can exhibit high adhesive strength and shear strength at room temperature and implement excellent deformation rate at a high temperature of 45℃.

[0047] According to one embodiment, the adhesive polymer of the adhesive layer of the sealing tape has a molecular weight and glass transition temperature within the above range, so that the sealing tape can exhibit excellent shear strength at room temperature and high deformation characteristics under battery charge and discharge conditions. In addition, the coulombic efficiency of an all-solid-state secondary battery including the sealing tape can be increased.

[0048] The adhesive polymer may be used without limitation as long as it satisfies the range of molecular weight and glass transition temperature, but may be derived from a compound including, for example, alkyl acrylate, hydroxy alkyl acrylate, cyclic alkyl acrylate, or a combination thereof.

[0049] The above alkyl acrylate may be a substituted or unsubstituted C1 to C20 alkyl (meth)acrylate compound, and is, for example, but not limited to, ethyl hexyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, lauryl (meth)acrylate, or a combination thereof.

[0050] The above hydroxy alkyl acrylate may be a C1 to C20 alkyl (meth)acrylate compound substituted with a hydroxy group, and examples thereof include, but are not limited to, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, chloro-2-hydroxypropyl acrylate, diethylene glycol mono(meth)acrylate, allyl alcohol, or a combination thereof.

[0051] The above cyclic alkyl acrylate may be a substituted or unsubstituted C3 to C20 cycloalkyl (meth)acrylate compound, and examples thereof include, but are not limited to, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, or a combination thereof.

[0052] In the above, (meth)acrylate means both acrylate and methacrylate.

[0053] The above adhesive polymer can be formed, for example, by crosslinking the aforementioned acrylate compound using a crosslinking agent. The crosslinking agent may be a multifunctional (meth)acrylate that can be cured with an active energy ray.

[0054] The above multifunctional (meth)acrylates include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentylglycol di(meth)acrylate, polyethyleneglycol di(meth)acrylate, neopentylglycol adipate di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified di(meth)acrylate, di(meth)acryloxy ethyl isocyanurate, allylated cyclohexyl di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, and dimethylol. Bifunctional acrylates such as dicyclopentane di(meth)acrylate, ethylene oxide-modified hexahydrophthalic acid di(meth)acrylate, tricyclodecane dimethanol(meth)acrylate, neopentylglycol-modified trimethylpropane di(meth)acrylate, adamantane di(meth)acrylate or 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene; Trifunctional acrylates such as trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, trifunctional urethane (meth)acrylate or tris(meth)acryloxyethyl isocyanurate; tetrafunctional acrylates such as diglycerin tetra(meth)acrylate or pentaerythritol tetra(meth)acrylate; pentafunctional acrylates such as dipentaerythritol penta(meth)acrylate; and hexafunctional acrylates such as dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, or urethane (meth)acrylates (e.g., reaction products of isocyanate monomers and trimethylolpropane tri(meth)acrylate), but are not limited thereto.These can be used alone or in combination of two or more.

[0055] In addition, conventional isocyanate-based, epoxy-based, aziridine-based, melamine-based, amine-based, imide-based, carbodiimide-based, amide-based crosslinking agents or combinations thereof may be used.

[0056] In the adhesive layer, the content of the crosslinking agent may be 0.01 to 5 parts by weight, specifically 0.03 to 3 parts by weight, and more specifically 0.05 to 2 parts by weight, based on 100 parts by weight of the (meth)acrylic copolymer.

[0057] The adhesive layer comprising the adhesive polymer may have a crosslinking degree of 85 to 98%. Here, the crosslinking degree can be determined by gel content. If the crosslinking degree of the adhesive layer is less than 85%, the adhesive layer may swell and disperse. Conversely, if the crosslinking degree of the adhesive layer exceeds 98%, the rigidity of the adhesive layer may be excessively high.

[0058] The adhesive layer can be manufactured by curing an adhesive layer composition comprising the acrylic compound and the crosslinking agent. For example, the adhesive layer composition can be coated on a release film and then UV cured. Specifically, the UV curing can be performed under conditions of 50 mW or less.

[0059] The above-described adhesive layer composition may further include, if necessary, conventional additives such as a silane coupling agent, a curing accelerator, an ionic liquid, a lithium salt, an inorganic filler, a softener, an antioxidant, an anti-aging agent, a stabilizer, a tackifying resin, a modifying resin, a leveling agent, an anti-foaming agent, a plasticizer, a pigment such as a dye, a coloring pigment, an extender pigment, a treating agent, an ultraviolet ray blocker, an optical whitening agent, a dispersant, a heat stabilizer, a light stabilizer, an ultraviolet ray absorber, an antistatic agent, a lubricant, and a solvent. The above-described modifying resin may further include a polyol resin, a phenol resin, an acrylic resin, a polyester resin, a polyolefin resin, an epoxy resin, an epoxidized polybutadiene resin, and the like, and may remain in the final adhesive layer.

[0060] The type or content of the acrylic compound, crosslinking agent, and additive in the adhesive layer composition used to form the aforementioned adhesive layer, and the molecular weight and T of the adhesive polymer g , and by appropriately adjusting the properties of the adhesive layer formed from the adhesive layer composition, it is possible to provide a sealing tape having a creep value and shear strength in a specific range at 45°C and 25°C, respectively, according to one embodiment.

[0061]

[0062] All-solid-state secondary battery

[0063] In another embodiment, an all-solid-state secondary battery is provided, comprising a battery assembly including a positive electrode, a solid electrolyte layer, and a negative electrode, and a sealing tape for the above-described all-solid-state secondary battery attached to at least a portion of the exterior of the battery assembly.

[0064] Fig. 1 is a schematic diagram schematically illustrating an example in which a sealing tape according to one embodiment is attached to an all-solid-state secondary battery (100). Fig. 2 is a top view of the all-solid-state battery (100) of Fig. 1 as viewed from above. As shown in Fig. 1, the sealing tape (600) for an all-solid-state secondary battery of one embodiment enables the cell structure (110) of the battery to form a laminated structure integrally without being separated.

[0065] The above sealing tape can be attached to four or more areas of the battery assembly, for example, five or more areas, six or more areas, but is not limited thereto. As an example, Fig. 1 shows a state in which the sealing tape is attached to six areas of the battery assembly, but is not limited thereto. In the above, the “area” can be said to refer to the number of sealing tapes attached across three or more surfaces among the surfaces forming the battery assembly. The shape in which the sealing tape is attached is not limited, and any shape is possible as long as it can integrate the cell structure forming the battery assembly.

[0066] The sealing tape may be attached in a range of 5 area% to 40 area% based on the total area of ​​the exterior of the battery assembly, for example, 10 area% to 40 area%, 15 area% to 40 area%, 5 area% to 35 area%, or 5 area% to 30 area%, but is not limited thereto. By attaching the sealing tape to the battery assembly in the range of the area, the sealing tape can integrate the cell structure at room temperature, and at the same time, the sealing tape can flexibly withstand expansion of the volume of the all-solid-state secondary battery under charge and discharge conditions of the battery, and the coulombic efficiency of the all-solid-state secondary battery including the sealing tape can be increased.

[0067] For example, an all-solid-state secondary battery may include two or more cell structures including a positive electrode, a negative electrode, and a solid electrolyte layer positioned between the positive electrode and the negative electrode. FIG. 3 is a cross-sectional view of an all-solid-state secondary battery according to one embodiment. Referring to FIG. 3, an all-solid-state secondary battery (100) is a structure in which a cell structure in which a negative electrode (400) including a negative electrode current collector (401) and a negative electrode active material layer (403), a solid electrolyte layer (300), and a positive electrode (200) including a positive electrode active material layer (203) and a positive electrode current collector (201) are laminated is housed in a battery case.

[0068] A single cell structure may include one or more cathodes, and likewise, may include one or more solid electrolyte layers, and may include one or more anodes. For example, the cell structure may be a mono-cell having a cathode / solid electrolyte layer / anode structure, or a bi-cell having a cathode / solid electrolyte layer / anode / solid electrolyte layer / cathode structure. In addition, although FIG. 3 illustrates an assembly in which two cell structures are stacked, three or more cell structures may be stacked, for example, 2 to 200, 3 to 100, 4 to 50, etc.

[0069] In addition, the all-solid-state secondary battery (100) may further include an elastic layer (500) on the outer side of at least one of the positive electrode (200) and the negative electrode (400). The elastic layer (500) allows pressure to be uniformly transmitted to the electrode stack to improve contact between solid components, and also serves to alleviate stress transmitted to the solid electrolyte, etc., and may serve to suppress cracks from occurring in the solid electrolyte due to stress accumulation according to changes in the thickness of the electrode during charging and discharging.

[0070] anode

[0071] In one embodiment, the device comprises a current collector and a positive electrode active material layer positioned on the current collector, wherein the positive electrode active material layer comprises a positive electrode active material and optionally may comprise a solid electrolyte, a binder, and / or a conductive material.

[0072] positive electrode active material

[0073] A compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound) can be used as a cathode active material. Specifically, one or more of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0074] The above composite oxide may be a lithium transition metal composite oxide, and specific examples thereof include lithium nickel-based oxide, lithium cobalt-based oxide, lithium manganese-based oxide, lithium iron phosphate-based compound, cobalt-free nickel-manganese-based oxide, lithium-rich layered oxide, or a combination thereof.

[0075] For example, the cathode active material may be a high-nickel cathode active material in which the nickel content is 80 mol% or more based on 100 mol% of metals excluding lithium in a lithium transition metal composite oxide. The nickel content in the high-nickel cathode active material may be 85 mol% or more, 90 mol% or more, 91 mol% or more, or 94 mol% or more, and 99 mol% or less based on 100 mol% of metals excluding lithium. The high-nickel cathode active material can realize high capacity and thus can be applied to high-capacity, high-density lithium secondary batteries.

[0076] As a more specific example, a compound represented by any one of the following chemical formulas may be used: Li a A 1-b X b O 2-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li a Mn 2-b X b O 4-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤0.5, 0 < α < 2);Li a Ni 1-b-c Mn b X c O 2-α D α(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.5, 0 < α < 2);Li a Ni b Co c L 1 d G e O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.1);; Li a NiG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a Mn 1-b G b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a Mn2G b O4(0.90 ≤ a ≤1.8, 0.001 ≤ b ≤ 0.1); Li a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8, 0 ≤ g ≤ 0.5); Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2); Li a FePO4(0.90 ≤ a ≤ 1.8)

[0077] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; Z is Cr, V, Fe, Sc, Y, or a combination thereof; L 1 is Mn, Al or a combination thereof.

[0078] The cathode active material may include, for example, a lithium nickel-based oxide represented by the following chemical formula 11, a lithium cobalt-based oxide represented by the following chemical formula 12, a lithium iron phosphate-based compound represented by the following chemical formula 13, a cobalt-free lithium nickel-manganese-based oxide represented by the following chemical formula 14, or a combination thereof.

[0079] [Chemical Formula 11]

[0080] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0081] In the above chemical formula 11, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, 0≤z1≤0.7, 0.9≤x1+y1+z1≤1.1, and 0≤b1≤0.1, and M 1 and M 2 are each independently one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0082] In the above chemical formula 1, 0.6≤x1≤1, 0≤y1≤0.4, and 0≤z1≤0.4, or 0.8≤x1≤1, 0≤y1≤0.2, and 0≤z1≤0.2.

[0083] [Chemical Formula 12]

[0084] Li a2 Co x2 M 3 y2 O 2-b2 X b2

[0085] In the above chemical formula 12, 0.9≤a2≤1.8, 0.7≤x2≤1, 0≤y2≤0.3, 0.9≤x2+y2≤1.1, and 0≤b2≤0.1, and M 3is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn and Zr, and X is one or more elements selected from the group consisting of F, P and S.

[0086] [Chemical Formula 13]

[0087] Li a3 Fe x3 M 4 y3 PO 4-b3 X b3

[0088] In the above chemical formula 13, 0.9≤a3≤1.8, 0.6≤x3≤1, 0≤y3≤0.4, and 0≤b3≤0.1, and M 4 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn and Zr, and X is one or more elements selected from the group consisting of F, P and S.

[0089] [Chemical Formula 14]

[0090] Li a4 Ni x4 Mn y4 M 5 z4 O 2-b4 X b4

[0091] In the above chemical formula 14, 0.9≤a2≤1.8, 0.8≤x4<1, 0 <y4≤0.2, 0≤z4≤0.2, 0.9≤x4+y4+z4≤1.1, 및 0≤b4≤0.1이고 M 5 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0092] The average particle diameter (D) of the above positive electrode active material 50 ) may be 1 ㎛ to 25 ㎛, for example, 3 ㎛ to 25 ㎛, 1 ㎛ to 20 ㎛, 1 ㎛ to 18 ㎛, 3 ㎛ to 15 ㎛, or 5 ㎛ to 15 ㎛. For example, the positive electrode active material may have an average particle diameter (D 50 ) with small particles of 1 ㎛ to 9 ㎛ and an average particle diameter (D 50 ) may include particles having a particle size range of 10 ㎛ to 25 ㎛. The positive electrode active material having such a particle size range can be harmoniously mixed with other components in the positive electrode active material layer and can realize high capacity and high energy density. Here, the average particle size is obtained by selecting 20 or so random particles from a scanning electron microscope image of the positive electrode active material, measuring their particle sizes (diameter, or major axis, or major axis length), and then obtaining a particle size distribution, and in the particle size distribution, the diameter (D) of the particles having a cumulative volume of 50% by volume 50 ) may be taken as the average particle diameter.

[0093] The above-mentioned positive electrode active material may be in the form of a secondary particle formed by agglomeration of a plurality of primary particles, or may be in the form of a single particle. In addition, the above-mentioned positive electrode active material may be spherical or nearly spherical in shape, or may be polyhedral or irregular in shape.

[0094] Meanwhile, the positive electrode active material may include a buffer layer on the particle surface. The buffer layer may be expressed as a coating layer, a protective layer, etc., and may play a role in lowering the interfacial resistance between the positive electrode active material and the sulfide-based solid electrolyte particles. For example, the buffer layer may include a lithium-metal-oxide, wherein the metal may be one or more elements selected from the group consisting of Al, B, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ta, V, W, and Zr. The lithium-metal-oxide is excellent in lowering the interfacial resistance between the positive electrode active material and the solid electrolyte particles while improving the performance of the positive electrode active material by facilitating the movement of lithium ions and electron conduction.

[0095] The positive electrode active material may be included in an amount of 55 wt% to 99.5 wt% based on 100 wt% of the positive electrode active material layer, for example, 65 wt% to 95 wt%, or 75 wt% to 91 wt%.

[0096] bookbinder

[0097] The binder helps the positive electrode active material particles adhere well to each other and also helps the positive electrode active material adhere well to the current collector. Representative examples of binders include, but are not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc.

[0098] Challenge

[0099] Conductive materials are used to impart conductivity to electrodes, and any material that does not cause chemical changes and is electronically conductive can be used in the battery. Examples of conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metallic materials containing copper, nickel, aluminum, silver, etc. in the form of metal powder or metal fibers; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0100] The content of the binder and the conductive agent may be 0.5 wt% to 5 wt%, respectively, with respect to 100 wt% of the positive electrode active material layer.

[0101] The cathode active material layer may optionally further include a solid electrolyte. The solid electrolyte may include, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof, and specific descriptions thereof will be provided later in the section on the solid electrolyte layer.

[0102] For 100 wt% of the positive electrode active material layer, the solid electrolyte may be included in an amount of 0.1 wt% to 35 wt%, for example, 1 wt% to 35 wt%, 5 wt% to 30 wt%, 8 wt% to 25 wt%, or 10 wt% to 20 wt%.

[0103] In the positive electrode active material layer, the positive electrode active material may be comprised in an amount of 65 to 99 wt% and the solid electrolyte in an amount of 1 to 35 wt%, based on 100 wt% of the total of the positive electrode active material and the solid electrolyte, for example, the positive electrode active material may be comprised in an amount of 80 to 90 wt% and the solid electrolyte in an amount of 10 to 20 wt%. When the solid electrolyte is comprised in the positive electrode in such an amount, the efficiency and life characteristics of the all-solid-state secondary battery can be improved without reducing the capacity.

[0104] Al may be used as the above current collector, but is not limited thereto.

[0105] cathode

[0106] An anode for an all-solid-state secondary battery may include a current collector and a negative electrode active material layer positioned on the current collector. The negative electrode active material layer includes a negative electrode active material and may further include a binder and / or a conductive material.

[0107] The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0108] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0109] As the above lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0110] As the material capable of doping and dedoping the lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used. The Si-based negative electrode active material is silicon, a silicon-carbon composite, SiOx(0 <x<2), Si-Q 합금(상기 Q는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소(Si를 제외함), 15족 원소, 16족 원소, 전이금속, 희토류 원소 및 이들의 조합에서 선택됨), 또는 이들의 조합일 수 있다. 상기 Sn계 음극 활물질로는 Sn, SnO2, Sn계 합금 또는 이들의 조합일 수 있다.

[0111] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the composite may include secondary particles (cores) in which silicon primary particles are assembled and an amorphous carbon coating layer (shell) positioned on the surface of the secondary particles. The amorphous carbon may also be positioned between the silicon primary particles, such that, for example, the silicon primary particles may be coated with amorphous carbon. The secondary particles may be dispersed and present in an amorphous carbon matrix.

[0112] The silicon-carbon composite may further comprise crystalline carbon. For example, the silicon-carbon composite may comprise a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer positioned on the surface of the core.

[0113] The above Si-based negative electrode active material or Sn-based negative electrode active material can be used in a mixture with a carbon-based negative electrode active material.

[0114] The content of the negative active material in the above negative active material layer may be 95 wt% to 99 wt% based on the total weight of the negative active material layer. For example, the negative active material layer may include 90 wt% to 99 wt% of the negative active material, 0.5 wt% to 5 wt% of the binder, and 0 wt% to 5 wt% of the conductive material.

[0115] The above binder serves to adhere the negative electrode active material particles well to each other and also to adhere the negative electrode active material well to the current collector. The binder may be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof.

[0116] Examples of the non-aqueous binder include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or combinations thereof.

[0117] The above-mentioned aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0118] When using an aqueous binder as the above-mentioned negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li.

[0119] The above dry binder is a polymeric material capable of being fiberized, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0120] The conductive material is used to provide conductivity to the electrode, and any material that does not cause chemical changes and is electronically conductive can be used in the battery. Specific examples include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metal-based materials in the form of metal powder or metal fibers, including copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0121] The negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof.

[0122] As another example, the negative electrode for an all-solid-state secondary battery may be a precipitation-type negative electrode. The precipitation-type negative electrode may refer to a negative electrode that does not include a negative electrode active material when the battery is assembled, but in which lithium metal or the like is precipitated or deposited on the negative electrode when the battery is charged, and this acts as a negative electrode active material.

[0123] (Precipitation type cathode)

[0124] Fig. 4 is a schematic cross-sectional view of an all-solid-state secondary battery including a precipitation-type negative electrode. Referring to Fig. 4, the precipitation-type negative electrode (400') may include a current collector (401) and a negative electrode coating layer (405) positioned on the current collector. An all-solid-state secondary battery including such a precipitation-type negative electrode (400') starts initial charging in a state in which no negative electrode active material is present, and during charging, high-density lithium metal is precipitated or deposited between the current collector (401) and the negative electrode coating layer (405) or on the negative electrode coating layer (405) to form a lithium metal layer (404), which may function as a negative electrode active material. Accordingly, in an all-solid-state secondary battery that has been charged more than once, the precipitation-type negative electrode (400') may include, for example, a current collector (401), a lithium metal layer (404) positioned on the current collector, and a negative electrode coating layer (405) positioned on the metal layer. The lithium metal layer (404) refers to a layer in which lithium metal or the like is precipitated during the charging process of the battery, and may be referred to as a metal layer, a lithium layer, a lithium deposition layer, or a negative electrode active material layer.

[0125] The above cathode coating layer (405) may be referred to as a lithium electrodeposition induction layer or a cathode catalyst layer, and may include a metal, a carbon material, or a combination thereof.

[0126] The metal may be a lithium-philic metal, and may include, for example, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, zinc, or a combination thereof, and may be composed of one of these or may be composed of several types of alloys. When the metal is present in the form of particles, the average particle diameter (D 50 ) may be less than about 4 μm, for example, 10 nm to 4 μm.

[0127] The carbon material may be, for example, crystalline carbon, amorphous carbon, or a combination thereof. The crystalline carbon may be, for example, natural graphite, artificial graphite, mesophase carbon microbeads, or a combination thereof. The amorphous carbon may be, for example, carbon black, activated carbon, acetylene black, Denka black, Ketjen black, or a combination thereof.

[0128] When the above-described negative electrode coating layer (405) includes both the metal and the carbon material, the mixing ratio of the metal and the carbon material may be, for example, a weight ratio of 1:10 to 2:1. In this case, the precipitation of lithium metal can be effectively promoted and the characteristics of the all-solid-state secondary battery can be improved. The above-described negative electrode coating layer (405) may include, for example, a carbon material supported with a catalytic metal, or may include a mixture of metal particles and carbon material particles.

[0129] The above-described cathode coating layer (405) may include, for example, the above-described lithium-philic metal and amorphous carbon, in which case the precipitation of the lithium metal may be effectively promoted. As a specific example, the cathode coating layer (405) may include a composite in which a lithium-philic metal is supported on amorphous carbon.

[0130] The above cathode coating layer (405) may further include a binder, and the binder may be, for example, a conductive binder. In addition, the above cathode coating layer (405) may further include general additives such as fillers, dispersants, and ionic conductive agents.

[0131] The thickness of the cathode coating layer (405) may be, for example, 100 nm to 20 ㎛, or 500 nm to 10 ㎛, or 1 ㎛ to 5 ㎛.

[0132] The above-described precipitated negative electrode (400') may further include, for example, a thin film on the surface of the current collector, i.e., between the current collector and the negative electrode coating layer. The thin film may include an element capable of forming an alloy with lithium. The element capable of forming an alloy with lithium may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., and may be composed of one type thereof or may be composed of multiple types of alloys. The thin film may further flatten the precipitated form of the lithium metal layer (404) and further improve the characteristics of the all-solid-state secondary battery. The thin film may be formed by, for example, a vacuum deposition method, a sputtering method, a plating method, etc. The thickness of the thin film may be, for example, 1 nm to 500 nm.

[0133] The lithium metal layer (404) may include lithium metal or a lithium alloy. The lithium alloy may be, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, or a Li-Si alloy.

[0134] The thickness of the lithium metal layer (404) may be 1 μm to 500 μm, 1 μm to 200 μm, 1 μm to 100 μm, or 1 μm to 50 μm. If the thickness of the lithium metal layer (404) is too thin, it may be difficult to perform the role of a lithium storage, and if it is too thick, the battery volume may increase and performance may deteriorate.

[0135] When such a precipitation-type cathode is applied, the cathode coating layer (405) can play a role in protecting the lithium metal layer (404) and suppressing the precipitation growth of lithium deadlight. Accordingly, short-circuiting and capacity reduction of the all-solid-state battery can be suppressed, and the life characteristics can be improved.

[0136] solid electrolyte layer

[0137] The solid electrolyte layer comprises a solid electrolyte. The solid electrolyte may be a type of inorganic solid electrolyte, and may include, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof. According to one embodiment, the solid electrolyte layer may comprise a sulfide-based solid electrolyte.

[0138] Sulfide-based solid electrolyte

[0139] Sulfide-based solid electrolytes include, for example, Li2S-P2S5, Li2S-P2S5-LiX (where X is a halogen element, for example, I or Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z. m S n (m, n are integers, Z is Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are integers, and M is P, Si, Ge, B, Al, Ga or In), or a combination thereof.

[0140] A sulfide-based solid electrolyte can be obtained, for example, by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20, and optionally heat-treating them. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be produced. The ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3.

[0141] Methods for mixing sulfur-containing raw materials for producing sulfide-based solid electrolytes include mechanical milling or the solution method. Mechanical milling involves placing raw materials in a ball mill reactor and vigorously stirring them to finely atomize and mix them. Using the solution method, the raw materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. Furthermore, heat treatment after mixing can solidify the crystals of the solid electrolyte and improve ionic conductivity. For example, a sulfide-based solid electrolyte can be produced by mixing sulfur-containing raw materials and heat-treating them twice or more, resulting in a sulfide-based solid electrolyte with high ionic conductivity and robustness.

[0142] According to one embodiment, sulfide-based solid electrolyte particles can be manufactured through, for example, a first heat treatment in which sulfur-containing raw materials are mixed and calcined at 120°C to 350°C, and a second heat treatment in which the first heat treatment result is mixed and calcined at 350°C to 800°C. The first heat treatment and the second heat treatment can each be performed in an inert gas or nitrogen atmosphere. The first heat treatment can be performed for 1 to 10 hours, and the second heat treatment can be performed for 5 to 20 hours. The first heat treatment can have the effect of milling small raw materials, and the second heat treatment can synthesize the final solid electrolyte. Through two or more such heat treatments, a high-performance sulfide-based solid electrolyte with high ionic conductivity and robustness can be obtained, and such a solid electrolyte can be said to be suitable for mass production. The temperature of the first heat treatment may be, for example, 150°C to 330°C, or 200°C to 300°C, and the temperature of the second heat treatment may be, for example, 380°C to 700°C, or 400°C to 600°C.

[0143] For example, the sulfide-based solid electrolyte particles may include argyrodite-type sulfides. The argyrodite-type sulfide-based solid electrolyte particles may have an ionic conductivity of 10, which is the ionic conductivity of a typical liquid electrolyte at room temperature. -4 10 inland -2 It has a high ionic conductivity approaching the S / cm range, can form a close bond between a positive electrode active material and a solid electrolyte without causing a decrease in ionic conductivity, and can further form a close interface between an electrode layer and a solid electrolyte layer. An all-solid-state secondary battery including the same can have improved battery performance, such as rate characteristics, Coulombic efficiency, and cycle life characteristics.

[0144] The argyrodite-type sulfide-based solid electrolyte particles may include, for example, a compound represented by the chemical formula 21 below.

[0145] [Chemical Formula 21]

[0146] (Li a M 1 b M 2 c )(P d M 3 e )(S f M 4 g )X h

[0147] In the above chemical formula 21, 4≤a≤8, and M 1 is Mg, Cu, Ag, or a combination thereof, and 0≤b<0.5, and M 2 is Na, K, or a combination thereof, 0≤c<0.5, and M 3 is Sn, Zn, Si, Sb, Ge, or a combination thereof, and 0 <d<4, 0≤e<1 이고, M 4 is O, SO n , or a combination thereof, and 1.5≤n≤5, 3≤f≤12, 0≤g<2, and X is F, Cl, Br, I, or a combination thereof, and 0≤h≤2.

[0148] For example, in chemical formula 21, a halide element (X) may be included as an essential element, in which case 0 <h≤2로 표시될 수 있다. 일 예로 화학식 21에 M 1 Elements may be required, in which case 0 <b<0.5로 표시될 수 있다. 화학식 21에서 M 3 can be understood as an element substituted in place of P and 0 <e<1일 수 있다. 화학식 21에서 M 4 is substituted in the S position, for example, 0 <g<2일 수 있으며 S의 비율인 f는 예를 들어 3≤f≤7일 수 있다. M 4 Go SO n If SO n It can be, for example, S4O6, S3O6, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, SO4, or SO5, and can be, for example, SO4.

[0149] For example, in chemical formula 21, a+b+c+h=7, d+e=1, and f+g+h=6.

[0150] As a specific example, argyrodite-type sulfide-based solid electrolyte particles include Li3PS4 and Li7P3S. 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 , Li 5.75 PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )PS 4.75 Cl 1.25 , (Li 5.72 Cu 0.03 )PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )P(S 4.70 (SO4) 0.05 )Cl 1.25 , (Li 5.69 Cu0.06 )P(S 4.60 (SO4) 0.15 )Cl 1.25 , (Li 5.72 Cu 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , (Li 5.72 Na 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , Li 5.75 P(S 4.725 (SO4) 0.025 )Cl 1.25 , or combinations thereof, but are not limited thereto.

[0151] An argyrodite-type sulfide-based solid electrolyte can be manufactured by mixing raw materials such as lithium sulfide, phosphorus sulfide, and optionally lithium halide. After mixing these, a heat treatment may be performed. The heat treatment may be performed at a temperature in the range of 400°C to 600°C, for example, 450°C to 500°C, or 460°C to 490°C, and for 5 to 30 hours, 10 to 24 hours, or 15 to 20 hours. When heat treating under the above conditions, ionic conductivity can be maximized. The heat treatment may include, for example, two or more heat treatment steps. Here, manufacturing an argyrodite-type sulfide-based solid electrolyte may include, for example, a first heat treatment of mixing raw materials and calcining at 120°C to 350°C, and a second heat treatment of mixing the first heat treatment resultant again and calcining at 350°C to 800°C.

[0152] Average particle diameter (D) of sulfide-based solid electrolyte particles 50) may be, for example, 0.1 ㎛ to 5.0 ㎛ or 0.1 ㎛ to 3.0 ㎛, may be small particles of 0.1 ㎛ to 1.9 ㎛, or may be large particles of 2.0 ㎛ to 5.0 ㎛. The sulfide-based solid electrolyte particles may be a mixture of small particles having an average particle diameter of 0.1 ㎛ to 1.9 ㎛ and large particles having an average particle diameter of 2.0 ㎛ to 5.0 ㎛. The average particle diameter of the sulfide-based solid electrolyte particles may be measured by an electron microscope image, and for example, a particle size distribution is obtained by measuring the size (diameter or major axis length) of about 20 particles in a scanning electron microscope image, where D 50 It may have been calculated.

[0153] Oxide-based solid electrolyte

[0154] Oxide-based solid electrolytes include, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 <x<2, 0<y<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12(0≤x≤1, 0≤y≤1), lithium lanthanum titanate (Li x La y TiO3, 0 <x<2, 0<y<3), Li2O, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr; x is an integer from 1 to 10), or mixtures thereof.

[0155] Halide-based solid electrolyte

[0156] The solid electrolyte layer may further include, for example, a halide-based solid electrolyte. The halide-based solid electrolyte contains a halogen element as a main component, and may mean that the ratio of the halide element to all elements constituting the solid electrolyte is 50 mol% or more, 70 mol% or more, 90 mol% or more, or 100 mol%. For example, the halide-based solid electrolyte may not contain a sulfur element.

[0157] The halide-based solid electrolyte may contain lithium element, a metal element other than lithium, and a halogen element. The metal element other than lithium may be Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof. The halogen element may be F, Cl, Br, I, or a combination thereof, and may be Cl, Br, or a combination thereof. The halide-based solid electrolyte may contain, for example, Li aM1X6 (M is Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof, X is F, Cl, Br, I, or a combination thereof, and 2≤a≤3) can be represented. The halide-based solid electrolyte may be, for example, Li2ZrCl6, Li 2.7 Y 0.7 Zr 0.3 Cl6, Li 2.5 Y 0.5 Zr 0.5 Cl6, Li 2.5 In 0.5 Zr 0.5 Cl6, Li2In 0.5 Zr 0.5 Cl6, Li3YBr6, Li3YCl6, Li3YBr2Cl4, Li3YbCl6, Li 2.6 Hf 0.4 Yb 0.6 Cl6, or combinations thereof, but is not limited thereto.

[0158] bookbinder

[0159] The solid electrolyte layer may further include a binder. Binders include, for example, nitrile-butadiene rubber, hydrogenated nitrile-butadiene rubber, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluoroelastomer, natural rubber, polydimethylsiloxane, polyethylene oxide, polyvinylpyrrolidone, polyvinylpyridine, chlorosulfonated polyethylene, polyvinyl alcohol, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, polyamideimide, polyimide, poly(meth)acrylate, polyacrylonitrile, polystyrene, polyurethane, and the like. copolymers, or combinations thereof.

[0160] The binder may be included in an amount of 0.1 wt% to 3 wt% based on 100 wt% of the solid electrolyte layer, for example, 0.5 wt% to 2 wt%, or 0.5 wt% to 1.5 wt%. When the binder is included in the above range, the components within the solid electrolyte layer can be well combined without lowering the ionic conductivity of the solid electrolyte, thereby improving the durability and reliability of the battery.

[0161] Other ingredients

[0162] The solid electrolyte layer may optionally further comprise an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0163] The above alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the solid electrolyte layer may be 1 M or more, for example, 1 M to 4 M. In this case, the lithium salt may improve ion conductivity by enhancing the lithium ion mobility of the solid electrolyte layer.

[0164] The lithium salt may be applied without limitation on type, and may include, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiSCN, LiN(CN)2, lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), lithium difluorobis(oxalato)phosphate (LiDFBP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, or a combination thereof.

[0165] For example, the lithium salt may be an imide-based lithium salt such as LiTFSI, LiFSI, LiBETI, or a combination thereof. The imide-based lithium salt can maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with the ionic liquid.

[0166] Ionic liquids are salts or molten salts that are composed only of ions and are liquid at room temperature, with a melting point below room temperature.

[0167] The ionic liquid comprises a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, trizolium, and mixtures thereof, and b) BF4. - , PF6 - , AsF6 - , SbF6 - , AlCl4 - , HSO4 - , ClO4 - , CH3SO3 - , CF3CO2 - , Cl - , Br - , I - , BF4 - , SO4 - , CF3SO3 - , (FSO2)2N - , (C2F5SO2)2N - , (C2F5SO2)(CF3SO2)N - , and (CF3SO2)2N - It may be a compound containing one or more anions selected from among.

[0168] The ionic liquid may be at least one selected from the group consisting of, for example, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide.

[0169] In the solid electrolyte layer, the weight ratio of the solid electrolyte to the ionic liquid may be 0.1:99.9 to 90:10, for example, 10:90 to 90:10, 20:80 to 90:10, 30:70 to 90:10, 40:60 to 90:10, or 50:50 to 90:10. A solid electrolyte layer satisfying the above range can maintain or improve ionic conductivity by improving the electrochemical contact area with the electrode. Accordingly, the energy density, discharge capacity, rate characteristics, etc. of the all-solid-state secondary battery can be improved.

[0170] The shape of the above-mentioned all-solid-state secondary battery is not particularly limited, and may be, for example, coin-shaped, button-shaped, sheet-shaped, stacked, cylindrical, flat, etc. In addition, the above-mentioned all-solid-state secondary battery can be applied to large-scale batteries used in electric vehicles, etc. For example, the above-mentioned all-solid-state secondary battery can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). In addition, it can be used in fields requiring a large amount of power storage, and for example, it can be used in electric bicycles or power tools, etc. In addition, the above-mentioned all-solid-state secondary battery can be used in various fields such as portable electronic devices.

[0171] Hereinafter, examples and comparative examples of the present invention are described. The following examples are merely examples of the present invention, and the present invention is not limited to the following examples.

[0172]

[0173] Example 1

[0174] 1. Manufacturing of sealing tape

[0175] A monomer mixture containing 85 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of 2-hydroxyethyl acrylate, and 10 parts by weight of isobornyl acrylate was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser. In addition, 0.1 part by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 85 parts by weight of ethyl acetate and 15 parts by weight of toluene for 100 parts by weight of the monomer mixture (solid content), and nitrogen gas was introduced while gently stirring to replace the mixture with nitrogen, and then the liquid temperature in the flask was maintained at around 55°C to perform a polymerization reaction for 8 hours, and the weight average molecular weight (M w ) is about 1,300,000 g / mol, and M w / M n A solution of an acrylic polymer having a molecular weight of 1.84 was prepared.

[0176] For 100 parts by weight of the solid content of the acrylic polymer solution obtained above, 0.1 part by weight of an isocyanate crosslinking agent (Takenate D110N, XDI, xylylene diisocyanate manufactured by Mitsui Chemicals) and 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane (KBM-403 manufactured by Shin-Etsu) were added to prepare a solution.

[0177] Next, the obtained solution was applied to one side of a 25 ㎛ thick PET film and treated at 135°C for 3 minutes to obtain a sealing tape with an adhesive layer formed on one side of the PET substrate.

[0178] 2. Manufacturing of an all-solid-state secondary battery including a sealing tape

[0179] LiNi coated with Li2O-ZrO2 0.8 Co 0.15 Mn 0.05A cathode composition was prepared by mixing 85 wt% of an O2 cathode active material, 13.5 wt% of a lithium argyrodite-type solid electrolyte Li6PS5Cl, 1.0 wt% of a polyvinylidene fluoride binder, and 0.5 wt% of a carbon nanotube conductive material. The prepared cathode composition was coated on an aluminum cathode current collector, dried, and rolled to prepare a cathode.

[0180] Primary entry (D 50 ) carbon black with an average particle diameter (D) of about 30 nm 50 ) was prepared by mixing silver (Ag) having a diameter of approximately 60 nm in a weight ratio of 3:1, and 0.25 g of the above complex was added to 2 g of an NMP solution containing 7 wt% of polyvinylidene fluoride binder and mixed to prepare a negative electrode coating layer composition. This was applied to a nickel foil current collector using a bar coater and vacuum-dried to prepare a deposition-type negative electrode in which a negative electrode coating layer was formed on the current collector.

[0181] An argyrodite-type solid electrolyte Li6PS5Cl(D) was added to a binder solution in which an acrylic binder (SX-A334, Zeon) was dissolved in an isobutyryl isobutyrate (IBIB) solvent. 50 =3㎛) was added and stirred to prepare a slurry. The slurry contains 98.5 wt% of solid electrolyte and 1.5 wt% of binder. The slurry was applied onto a release PET film using a bar coater and dried at room temperature to prepare a solid electrolyte layer.

[0182] Bi-cell type cell structures were manufactured by stacking in the order of negative electrode / solid electrolyte / positive electrode / solid electrolyte / negative electrode. The final battery structure was manufactured by stacking five cell structures and interposing elastic sheets between the cell structures and on the outermost surface. This was placed in an aluminum pouch laminate film and subjected to warm isostatic pressing (WIP) at 80°C and 500 MPa for 30 minutes. The sealing tape manufactured above was attached to the outer surface of the pressed battery structure in at least six areas in the form of FIG. 1 to manufacture the final all-solid-state secondary battery.

[0183]

[0184] Example 2

[0185] An all-solid-state secondary battery was manufactured in substantially the same manner as in Example 1, except that 0.05 part by weight of the isocyanate crosslinking agent D110N was used instead of 0.1 part by weight.

[0186]

[0187] Example 3

[0188] An all-solid-state secondary battery was manufactured in substantially the same manner as in Example 1, except that 90 parts by weight of n-butylacrylate was used instead of 85 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of 2-hydroxybutyl acrylate was used instead of 5 parts by weight of 2-hydroxyethyl acrylate, and 5 parts by weight of isobornyl acrylate was used instead of 10 parts by weight.

[0189]

[0190] Comparative Example 1

[0191] An all-solid-state secondary battery was manufactured in substantially the same manner as in Example 1, except that 70 parts by weight of 2-ethylhexyl acrylate was used instead of 85 parts by weight, 10 parts by weight of 2-hydroxyethyl acrylate was used instead of 5 parts by weight, and 20 parts by weight of isobornyl acrylate was used instead of 10 parts by weight.

[0192]

[0193] Comparative Example 2

[0194] An all-solid-state secondary battery was manufactured in substantially the same manner as in Example 1, except that Tapex's 3221 Series PET film was used instead of the sealing tape obtained in Example 1.

[0195]

[0196] Comparative Example 3

[0197] An all-solid-state secondary battery was manufactured in substantially the same manner as in Example 1, except that 70 parts by weight of n-butylacrylate was used instead of 85 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of 2-hydroxybutylacrylate was used instead of 5 parts by weight of 2-hydroxyethyl acrylate, 25 parts by weight of isobornyl acrylate was used instead of 10 parts by weight, and 0.2 parts by weight of the isocyanate crosslinking agent D110N was used instead of 0.1 parts by weight.

[0198]

[0199] Comparative Example 4

[0200] An all-solid-state secondary battery was manufactured in substantially the same manner as in Example 1, except that 65 parts by weight of 2-ethylhexyl acrylate was used instead of 85 parts by weight, 10 parts by weight of 2-hydroxybutylacrylate was used instead of 5 parts by weight of 2-hydroxyethyl acrylate, 25 parts by weight of isobornyl acrylate was used instead of 10 parts by weight, and 0.2 parts by weight of 1,6-hexanediol diacrylate (HDDA) was used instead of D110N as a crosslinking agent.

[0201]

[0202] Evaluation 1: Shear strength

[0203] Each of the sealing tapes manufactured in the above examples and comparative examples is cut to a size of (1 in) X (1 in) to prepare a sample. A glass plate (710, 720) is laminated to both sides of the prepared sealing tape (610), thereby manufacturing a specimen as shown in Fig. 5(a).

[0204] Shear strength is the maximum value of shear stress, and as shown in Fig. 5(b), the shear strength is measured by pulling both ends of two glass plates (710, 720) at a speed of 12.5 mm / min. Specifically, the specimen is left at 25°C for 2 hours and then the shear strength is measured using a UTM (SHIMADZU AGS-X). In addition, the specimen is left at 45°C for 2 hours and then the shear strength is measured using the same method as above. The results are as shown in Table 1 below.

[0205]

[0206] Rating 2: Creep

[0207] Each of the sealing tapes manufactured in the above examples and comparative examples is cut to a size of 1 cm in width to prepare a specimen. As shown in FIG. 6(a) and FIG. 6(b), the prepared specimen (620) is adhered to the end of a glass plate (730) so that the bonding area is 1 cm X 1 cm. Then, using a TA.XT Plus Texture Analyzer (Stable Micro System (manufactured)), the sealing tape specimen (620) is pulled at a speed of 10 μm / s for 1 minute under a load (W) of 1 kgf at 25°C and 45°C. As shown in FIG. 6(c), the sealing tape specimen (620) can be pushed from the glass plate (730), and at this time, the distance (Creep, [μm]) that the sealing tape specimen is pushed from the glass plate is measured. As a result, the creep values ​​and the ratio of the creep values ​​to the adhesive layer thickness at 25°C and 45°C, respectively, are as shown in Table 1 below. At this time, the thickness of the adhesive layer was measured through photographs taken with an optical microscope such as a scanning electron microscope.

[0208]

[0209] Evaluation 3: Adhesion

[0210] Each of the sealing tapes manufactured in the above examples and comparative examples was maintained at 25°C for 2 hours under a load of 50 kg, and then a peeling test was conducted using a peeling tester to pull in a 180° direction at a peeling speed of 100 mm / min. The force required to peel 40 mm was measured and shown as adhesive strength in Table 1 below.

[0211]

[0212] Evaluation 4: Electrochemical Characteristics of All-Solid-State Batteries

[0213] For all-solid-state batteries using tapes manufactured in Examples and Comparative Examples, the coulombic efficiency and lifespan were evaluated using the following methods. The evaluation results are shown in Table 1 below.

[0214] (1) Coulomb efficiency

[0215] For the all-solid-state battery, initial charging and discharging were performed by charging to an upper limit voltage of 4.25 V with a constant current of 0.1 C at 45°C and then discharging to an end voltage of 2.5 V at 0.1 C.

[0216] [Formula 1]

[0217] Coulomb efficiency = 100 * (initial discharge capacity / initial charge capacity)

[0218] (2) Lifespan

[0219] After the above Coulomb efficiency measurement, charging at 0.33C and discharging at 0.33C in a voltage range of 2.5 V to 4.25 V at 45°C were repeated more than 300 times, and the number of cycles at which the discharge capacity retention rate for the initial discharge dropped to 80% was evaluated.

[0220] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Adhesive layer thickness 5um 10um 5um 5um 6um 25um 25um 25℃ Adhesive strength (180 Peel) 350 420 380 250 500 750 650 Shear strength (kgf / cm) 2)42.883.83.63.34.54.8Creep(um)5075651401806055Creep(um) / Thickness(um)107.51328302.42.245℃Shear strength(kgf / cm) 2 )0.981.011.10.80.60.61.6Creep(um)500↑500↑500↑500↑500↑200150Creep(um) / Thickness(um)1005010010083.3333386C.E93949390908583Life>300>300>3002301808075

[0221] Referring to Table 1 above, it can be confirmed that the sealing tape according to the embodiment has a shear strength equivalent to or superior to that of the sealing tape according to the comparative example at 25°C, and at the same time, has excellent high-deformation characteristics due to a high creep value and a high ratio of the creep value to the adhesive layer thickness at 45°C. That is, when the sealing tape according to the embodiment is used, the cell structure may not be separated in the manufacturing environment of an all-solid-state secondary battery, and when charging and discharging the battery, the stress applied to the solid electrolyte in the battery may be dispersed and a uniform surface pressure may be maintained, thereby increasing the coulombic efficiency of the battery.

[0222] Although the preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts defined in the following claims also fall within the scope of the present invention.

[0223]

[0224] [Explanation of symbols]

[0225] 100: All-solid-state battery 110: Cell structure

[0226] 200: Anode 201: Anode current collector

[0227] 203: Cathode active material layer 300: Solid electrolyte layer

[0228] 400: Cathode 401: Cathode current collector

[0229] 403: Negative active material layer 404: Lithium metal layer

[0230] 405: Cathode coating layer 500: Elastic layer

Claims

1. A sealing tape for an all-solid-state secondary battery, comprising a substrate and an adhesive layer positioned on one side of the substrate, The creep value at 45℃ is 500㎛ or more, and the shear strength at 45℃ is 0.98 kgf / cm 2 Ideal sealing tape for all-solid-state secondary batteries.

2. In paragraph 1, The above sealing tape is an all-solid-state secondary battery sealing tape having a ratio of creep (㎛) value to adhesive layer thickness (㎛) of 50 or more at 45°C.

3. In paragraph 1, The above sealing tape has a creep value of 100㎛ or less and a shear strength of 2.0 kgf / cm at 25℃. 2 Ideal sealing tape for all-solid-state secondary batteries.

4. In paragraph 1, The above sealing tape is a sealing tape for an all-solid-state secondary battery having a ratio of creep value to adhesive layer thickness at 25°C of 15 or less.

5. In paragraph 1, The above sealing tape is a sealing tape for an all-solid-state secondary battery having an adhesive strength of 300 gf / mm or more at 25°C.

6. In paragraph 1, A sealing tape for an all-solid-state secondary battery, wherein the thickness of the sealing tape is 10 ㎛ to 100 ㎛.

7. In paragraph 1, A sealing tape for an all-solid-state secondary battery having a thickness of 5 ㎛ to 50 ㎛ as described above.

8. In paragraph 1, A sealing tape for an all-solid-state secondary battery, wherein the thickness of the adhesive layer is 5 ㎛ to 50 ㎛.

9. In paragraph 1, The above-mentioned description relates to an all-solid-state secondary battery sealing tape comprising polyethylene terephthalate, polyethylene, polypropylene, polyamide, polyimide, polyethylene naphthalate, polyacrylonitrile, poly(meth)acrylate, polymethyl(meth)acrylate, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl chloride, polyurethane, epoxy resin, nylon resin, acrylic resin, polystyrene, polyethylene oxide, polyvinyl alcohol, silicone resin, styrene-butadiene rubber, acrylonitrile-butadiene rubber, hydrogenated nitrile-butadiene rubber, copolymers thereof, or mixtures thereof.

10. In paragraph 1, A sealing tape for an all-solid-state secondary battery, wherein the adhesive layer comprises an adhesive polymer, and the molecular weight of the adhesive polymer is 800,000 g / mol to 3,500,000 g / mol.

11. In Article 10, A sealing tape for an all-solid-state secondary battery, wherein the glass transition temperature (Tg) of the adhesive polymer is -50°C to -5°C.

12. In Article 10, The above adhesive polymer is an all-solid-state secondary battery sealing tape derived from alkyl acrylate, hydroxy alkyl acrylate, cyclic alkyl acrylate, or a combination thereof.

13. A battery assembly comprising a positive electrode, a solid electrolyte layer, and a negative electrode, and An all-solid-state secondary battery comprising a sealing tape for an all-solid-state secondary battery according to any one of claims 1 to 12, attached to at least a portion of the exterior of the battery assembly.

14. In paragraph 13, An all-solid-state secondary battery in which the above sealing tape is attached to four or more areas of the above battery assembly.

15. In paragraph 13, An all-solid-state secondary battery in which the sealing tape is attached in a range of 5 to 40 area% based on the total area of ​​the exterior of the battery assembly.

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