All-solid-state secondary battery comprising frame structure and method for manufacturing same

Abstract

The present invention relates to an all-solid-state secondary battery having a battery stack in which one or more all-solid-state battery cells are stacked, and a method for manufacturing same. The all-solid-state battery cell comprises one or more cathode layers, one or more solid electrolyte layers, and one or more anode layers, and a frame structure surrounding at least a part of the side circumference of the cathode layer. The gap in a plane direction perpendicular to the stacking direction between the cathode layer and the frame structure or the gap in the stacking direction between the cathode layer and the frame structure is 50 um or less. According to the present invention, as the frame structure has fluidity by a pressing process (for example, an isostatic pressing process), the gap in a plane direction perpendicular to the stacking direction between the cathode layer and the frame structure and / or the gap in the stacking direction between the solid electrolyte layer and the frame structure may be substantially removed or reduced.

Description

All-solid-state secondary battery including a frame structure and method for manufacturing the same

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 2025-0011467 filed January 24, 2025 and Korean Patent Application No. 2026-0008076 filed January 15, 2026, and all contents disclosed in the documents of said Korean patent applications are incorporated herein as part of this specification.

[0003] Technology field

[0004] The present invention relates to an all-solid-state secondary battery comprising a frame structure and a method for manufacturing the same.

[0005] All-solid-state batteries generally include a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. Since the interfacial resistance between the positive electrode, solid electrolyte layer, and negative electrode layer is high, a pressurization process is essential for cell operation. However, there is a problem in that the negative electrode layer and the solid electrolyte layer may bend during the pressurization process, potentially leading to the failure of the solid electrolyte layer and deformation of the positive electrode layer.

[0006] The present invention aims to solve the above problem and can provide an all-solid-state secondary battery and a method for manufacturing the same that can prevent deformation of one or more of the positive electrode layer, solid electrolyte layer, and negative electrode layer that may occur during the pressurization process of the all-solid-state secondary battery.

[0007] In one embodiment, the present invention may relate to an all-solid-state secondary battery having a battery stack having one or more all-solid-state battery cells, wherein each of the all-solid-state battery cells comprises one or more positive electrode layers, a solid electrolyte layer, and a negative electrode layer, and comprises a frame structure surrounding at least a portion of the lateral perimeter of the positive electrode layer, and the gap in a planar direction perpendicular to the stacking direction between the positive electrode layer and the frame structure is 50 μm or less.

[0008] In one embodiment, the frame structure may include a polymer resin satisfying the following condition 1:

[0009] [Condition 1]

[0010] Glass transition temperature (T) of polymer resin g ) or softening point ≤ pressurized temperature.

[0011] In one embodiment, the pressurization temperature may be an isotropic pressurization temperature.

[0012] In one embodiment, the frame structure has a glass transition temperature (T g It may include a polymer resin with a softening point of 200°C or lower.

[0013] In one embodiment, the frame structure is at a crystallization temperature (T c It may include a polymer resin that is greater than the pressurization temperature.

[0014] In one embodiment, the frame structure comprises a polymer resin, and the polymer resin may include one or more selected from the group consisting of polyolefin resin, fluorine resin, cellulose resin, epoxy resin, vinyl resin, acrylic resin and polystyrene resin.

[0015] In one embodiment, the frame structure may surround at least 80% of the entire perimeter of the side of the anode layer.

[0016] In one embodiment, the upper end of the anode layer may be located on the same line in the planar direction as the upper end of the frame structure, and the lower end of the anode layer may be located on the same line in the planar direction as the lower end of the frame structure.

[0017] In one embodiment, the frame structure may be a single-layer structure or a multi-layer structure.

[0018] In one embodiment, when viewed from the stacking direction, the area of ​​the anode layer may be smaller than the area of ​​the solid electrolyte layer.

[0019] In one embodiment, when viewed from the stacking direction, the sum of the areas of the anode layer and the frame structure may be equal to or greater than the area of ​​the solid electrolyte layer.

[0020] In one embodiment, the all-solid-state battery cell may be a monocell, a bicell, or a multi-stack cell.

[0021] In one embodiment, the present invention may relate to a method for manufacturing an all-solid-state secondary battery having a battery stack having one or more all-solid-state battery cells, wherein the all-solid-state battery cell comprises one or more positive electrode layers, a solid electrolyte layer, and a negative electrode layer, and comprises the steps of: introducing a frame structure on the side of the positive electrode layer; and pressing the all-solid-state battery cell, wherein the gap in a planar direction perpendicular to the stacking direction between the positive electrode layer and the frame structure is 50 μm or less.

[0022] In one embodiment, the frame structure may include a polymer resin satisfying the following condition 1:

[0023] [Condition 1]

[0024] Glass transition temperature (T) of polymer resin g ) or softening point ≤ pressurized temperature.

[0025] In one embodiment, the step of introducing a frame structure to the side of the anode layer may involve introducing and curing a polymer resin composition to form a frame structure, or forming a frame structure and then introducing it to the side of the anode layer.

[0026] In one embodiment, the gap in a planar direction perpendicular to the stacking direction between the anode layer and the frame structure may be smaller after the step of pressurizing the all-solid-state battery cell than before the step of pressurizing the all-solid-state battery cell.

[0027] According to the present invention, as the frame structure becomes fluid through a pressurization process, the gap in the planar direction perpendicular to the stacking direction between the anode layer and the frame structure and / or the gap in the stacking direction between the solid electrolyte layer and the frame structure can be substantially eliminated or reduced. Accordingly, by preventing the phenomenon of the cathode layer and / or the solid electrolyte layer bending and deforming, and the phenomenon of the anode layer sliding, it is possible to provide an all-solid-state secondary battery having excellent performance without cracking of the solid electrolyte layer and a method for manufacturing the same.

[0028] The drawings in this specification are intended merely to aid in understanding the invention, and the scope of the invention should not be interpreted as being limited to the embodiments described in the drawings. Thicknesses have been enlarged or reduced in the drawings to clearly represent various layers and regions. Throughout the specification, the same reference numerals have been used for similar parts. In this specification and drawings, components having substantially the same functional configuration are referred to by the same reference numerals, and redundant descriptions are omitted.

[0029] FIG. 1 is a schematic diagram of the appearance of an anode layer and a frame structure before and after pressurization according to an example of the present invention, viewed from the stacking direction.

[0030] FIG. 2 is a cross-sectional view showing the appearance of an all-solid-state secondary battery before and after pressurization according to an example of the present invention.

[0031] Figure 3 shows a top view (left) of the anode layer and frame structure before and after isotropic pressurization of an embodiment of the present invention, and the results of roughness measurement of the anode layer and frame structure (right). In the left image of Figure 3, the dark gray area represents the anode layer, the bright area represents the frame structure, and the black area represents the gap between the anode layer and the frame structure.

[0032] Figure 4 shows a top view (left) of the anode layer and frame structure before and after isotropic pressurization of the comparative example of the present invention, and the results of roughness measurement of the anode layer and frame structure (right). In the left image of Figure 4, the dark gray area represents the anode layer, the bright area represents the frame structure, and the black area represents the gap between the anode layer and the frame structure.

[0033] FIG. 5 is a flowchart of a method for manufacturing an all-solid-state secondary battery according to an example of the present invention.

[0034] Terms and words used in this specification and claims shall not be interpreted as being limited to their ordinary or dictionary meanings, but shall be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0035] Therefore, it should be understood that the configuration of the embodiments described in this specification is merely one of the most preferred embodiments of the present invention and does not represent all of the technical ideas of the present invention, and that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0036] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0037] In this specification, when a part is described as “comprising” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Thus, for example, a composition comprising compound A may include compounds other than A. However, the term “comprising” also encompasses, in a more restrictive sense as a specific embodiment thereof, “essentially / essentially composed of” and “composed of”; for example, a “composition comprising compound A” may also be (essentially / essentially) composed of compound A.

[0038] In connection with this, terms such as “comprising” or “having,” as described in this specification, are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should not be understood as precluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0039] In this specification, when any layer is described as being located “on” or “between” another arbitrary layer, this includes not only cases where any layer is in contact with another arbitrary layer, but also cases where another layer or material, etc., exists between the two layers.

[0040] Where in this specification a quantity, concentration, or other value or parameter is given as an enumeration of a range, a preferred range, a preferred upper limit, and a preferred lower limit, it should be understood that any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether the range is disclosed separately, specifically discloses all ranges that may be formed. Where a range of numerical values ​​is mentioned in this specification, unless otherwise stated, for example, without limiting terms such as greater than or less than, the range is intended to include its endpoint value and all integers and fractions within that range. The scope of the invention is not intended to be limited to the specific value mentioned when defining the range.

[0041] In the present specification, where “about” is written before a specific numerical value or the upper and lower limits of a specific numerical range, unless specifically otherwise stipulated, it means that the numerical value or the upper and lower limits of the numerical range following “about” may be a value within an error range without departing from the technical concept of the present invention. In this case, for example, the error range may be ±5%, and in this case, the description “about 1 mm” means that it may be “0.95 mm to 1.05 mm”.

[0042] In this specification, "A is identical" means that A is substantially identical. For example, "the thicknesses of a and b are identical" means that the thicknesses of a and b are substantially identical, and may include the difference between the thickness of a and the thickness of b being within an error range of ±5%.

[0043] Among the physical properties mentioned in this specification, if the measured temperature affects the property, the property is measured at room temperature unless specifically otherwise specified. The term "room temperature" refers to a natural temperature that has not been heated or cooled, and may mean, for example, any temperature within the range of about 10°C to 30°C, about 23°C, or about 25°C. Furthermore, unless specifically otherwise specified, the unit of temperature in this specification is °C.

[0044] In addition, among the physical properties mentioned in this specification, if the measured pressure affects the physical property, unless specifically otherwise specified, the physical property is measured at normal pressure, that is, atmospheric pressure (about 1 atmosphere).

[0045] The details regarding all-solid-state secondary batteries described in this specification may relate to all-solid-state secondary batteries after pressurization, unless specifically described otherwise.

[0046] The first aspect of the present invention relates to an all-solid-state secondary battery.

[0047] The all-solid-state secondary battery of the present invention is, for example, an all-solid-state secondary battery having a battery stack in which one or more all-solid-state battery cells are stacked, wherein the all-solid-state battery cells may each include, for example, one or more positive electrode layers, a solid electrolyte layer, and a negative electrode layer, and may include a frame structure that surrounds at least a portion of the lateral perimeter of the positive electrode layer.

[0048] For example, the all-solid-state secondary battery of the present invention may have a gap in a planar direction perpendicular to the stacking direction between the anode layer and the frame structure of 50 μm or less. Unless specifically described otherwise in this specification, the gap in a planar direction perpendicular to the stacking direction between the anode layer and the frame structure may refer to the gap after pressurization. The gap in a planar direction perpendicular to the stacking direction between the anode layer and the frame structure may be measured in the manner according to the evaluation example described below. In other examples, the gap in a planar direction perpendicular to the stacking direction between the anode layer and the frame structure may be 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, 15 μm or less, 10 μm or less, 5 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less, and preferably 0.

[0049] In the all-solid-state secondary battery of the present invention, for example, the gap in the stacking direction between the solid electrolyte layer and the frame structure may be 100 μm or less. Unless specifically described otherwise in this specification, the gap in the stacking direction between the solid electrolyte layer and the frame structure may refer to the gap after pressurization. The gap in the stacking direction between the solid electrolyte layer and the frame structure may be measured in the manner according to the evaluation example described below. In other examples, the gap in the stacking direction between the solid electrolyte layer and the frame structure may be 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, 10 μm or less, or 5 μm or less, and preferably 0.

[0050] In the all-solid-state secondary battery of the present invention, for example, the upper end of the positive layer may be located on the same plane as the upper end of the frame structure, and the lower end of the positive layer may be located on the same plane as the lower end of the frame structure. That is, in the all-solid-state secondary battery of the present invention, for example, the thickness of the positive layer and the thickness of the frame structure may be the same. In this specification, the thickness of the frame structure may refer to the thickness in the stacking direction.

[0051] The all-solid-state secondary battery of the present invention can have excellent performance without cracking of the solid electrolyte layer by preventing the phenomenon of bending and deformation of the negative electrode layer and / or the solid electrolyte layer and the phenomenon of sliding of the positive electrode layer, as well as by substantially eliminating or reducing the gap in the planar direction perpendicular to the stacking direction between the positive electrode layer and the frame structure and / or the gap in the stacking direction between the solid electrolyte layer and the frame structure as described above. The above objective of the present invention can be achieved by controlling the frame structure to have the following characteristics so that the frame structure has fluidity through a pressurization process.

[0052] The above frame structure may include, for example, a polymer resin satisfying the following condition 1:

[0053] [Condition 1]

[0054] Glass transition temperature (T) of polymer resin g ) or softening point ≤ pressurized temperature.

[0055] The above glass transition temperature (T g ) refers to the center of the temperature region where an amorphous solid changes from a glass-like state to a viscous, soft state, or the temperature at which the gradient of the specific volume versus temperature curve changes abruptly. The glass transition temperature (T gThe softening point may be measured, for example, by a method according to Differential Scanning Calorimetry (DSC), Thermo Mechanical Analysis (TMA), or Dynamic Mechanical Analysis (DMA), or by a method such as ISO 6721-11. The softening point may be measured, for example, by the Vicat method according to ISO 306, the Heat Deflection Test according to ISO 75, or the ring and ball method according to ISO 4625-1.

[0056] The above pressurization temperature may refer to the maximum temperature reached by the pressurized object (e.g., an all-solid-state secondary battery) through the pressurization process. The pressurization process described herein, including the above pressurization process, may be an isotropic pressurization process, a uniaxial hot press process, or a roll press process. In terms of effectively reducing the interfacial resistance between the solid electrolyte layer and the electrode, the pressurization process described herein, including the above pressurization process, may be an isotropic pressurization process. If the pressurization process described herein, including the above pressurization process, is an isotropic pressurization process, the temperature of the pressurized object may reach the temperature of the fluid for isotropic pressurization through the isotropic pressurization process. If the pressurization process described herein, including the above pressurization process, is a uniaxial hot press process or a roll press process, a separate heating process may be performed before, simultaneously with, or after the pressurization process to increase the temperature of the pressurized object.

[0057] The above pressurized temperature may be, for example, 60°C to 200°C. The above pressurized temperature is, in other examples, 65°C or higher, 70°C or higher, 75°C or higher, 80°C or higher, 85°C or higher, 90°C or higher, 95°C or higher, 100°C or higher, 105°C or higher, 110°C or higher, 115°C or higher, 120°C or higher, 125°C or higher, 130°C or higher, 135°C or higher, 140°C or higher, 145°C or higher, 150°C or higher, 155°C or higher, 160°C or higher, 165°C or higher, 170°C or higher, 175°C or higher, 180°C or higher, 185°C or higher, 190°C or higher, 195°C or higher, or 200°C or higher, or 190°C or lower, 180°C or lower, 170°C or lower, 160°C or lower, 150°C or lower, 140°C or lower, 130°C It may be 120℃ or lower, 110℃ or lower, 100℃ or lower, or 90℃ or lower.

[0058] The above frame structure is, for example, at the glass transition temperature (T g It may include a polymer resin having a softening point of 200°C or lower. The glass transition temperature (T) of the polymer resin g ) or the softening point in other examples is 195°C or lower, 190°C or lower, 185°C or lower, 180°C or lower, 175°C or lower, 170°C or lower, 165°C or lower, 160°C or lower, 155°C or lower, 150°C or lower, 145°C or lower, 140°C or lower, 135°C or lower, 130°C or lower, 125°C or lower, 120°C or lower, 115°C or lower, 110°C or lower, 105°C or lower, 100°C or lower, 95°C or lower, 90°C or lower, 85°C or lower, 80°C or lower, 75°C or lower, 70°C or lower, 65°C or lower, or 60°C or lower, or 30°C or higher, 35°C or higher, 40°C or higher, 45°C or higher, 50°C or higher, 55°C or higher, 60°C or higher, 65°C or higher, It may be 70℃ or higher, 75℃ or higher, or 80℃ or higher.

[0059] The above frame structure is, for example, at a crystallization temperature (T cIt may include a polymer resin with a temperature greater than the pressurization temperature. Through this, the problem of difficulty in controlling the position of the frame structure due to excessively high fluidity during the pressurization process can be solved.

[0060] Crystallization temperature (T) of the above polymer resin c ) can be, for example, 90℃ to 250℃. The crystallization temperature (T) of the polymer resin is c ) in other examples 95℃ or higher, 100℃ or higher, 110℃ or higher, 120℃ or higher, 125℃ or higher, 130℃ or higher, 135℃ or higher, 140℃ or higher, 145℃ or higher, 150℃ or higher, 155℃ or higher, 160℃ or higher, 165℃ or higher, 170℃ or higher, 175℃ or higher, 180℃ or higher, 185℃ or higher, 190℃ or higher, 195℃ or higher, 200℃ or higher, 205℃ or higher, 210℃ or higher, 215℃ or higher, 220℃ or higher, 225℃ or higher, or 230℃ or higher, or 245℃ or lower, 240℃ or lower, 235℃ or lower, 230℃ or lower, 225℃ or lower, 220℃ or lower, 215℃ or lower, 210℃ or lower, It may be 205℃ or lower, 200℃ or lower, 195℃ or lower, 190℃ or lower, 180℃ or lower, 170℃ or lower, 160℃ or lower, 150℃ or lower, 140℃ or lower, or 130℃ or lower.

[0061] The above frame structure also, for example, has a melting point (T m ) is the pressurization temperature or crystallization temperature (T c It may contain a polymer resin with a higher polymer content than ).

[0062] The above polymer resin may include one or more selected from the group consisting of, for example, polyolefin resin, fluorine resin, cellulose resin, epoxy resin, vinyl resin, acrylic resin, and polystyrene resin. The above polyolefin resin may include one or more selected from the group consisting of, for example, low-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene monomer rubber, ethylene-butene copolymer, ethylene-octene copolymer, propylene-ethylene block copolymer, ethylene-vinyl acetate, ethylene-propylene-octene copolymer, ethylene-hexene copolymer, and polybutene. The above-mentioned fluorine-based resin may be, for example, a homopolymer of vinylidene fluoride monomer, or a copolymer of vinylidene fluoride monomer and one or more fluorine-containing monomers selected from tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, fluorovinyl, and perfluoroalkyl vinyl ether. Specifically, the vinylidene-based monomer may be a vinylidene fluoride homopolymer, a vinylidene fluoride-hexafluoropropylene copolymer, a vinylidene fluoride-chlorotrifluoroethylene copolymer, etc. The above-mentioned cellulose-based resin may include, for example, one or more selected from the group consisting of cellulose, methyl cellulose, ethyl cellulose, butyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate. There is no limitation on the form of the above-mentioned cellulose-based polymer, but it may be, for example, in the form of nanofibers.The above epoxy resin may include one or more selected from the group consisting of, for example, cresol novolak epoxy resin, bisphenol A type epoxy resin, bisphenol A type novolak epoxy resin, phenol novolak epoxy resin, tetrafunctional epoxy resin, biphenyl type epoxy resin, triphenol methane type epoxy resin, alkyl modified triphenol methane epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, dicyclopentadiene modified phenol type epoxy resin, and urethane modified epoxy resin. The above vinyl resin may be, for example, polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, polyvinylidene chloride, polyvinyl ether, polyvinyl butyral, or polyvinylpyrrolidone. The above acrylic resin may be, for example, polymethyl methacrylate, polyacrylic acid, polymethyl methacrylate, polyacrylonitrile, ethylene-acrylic acid copolymer, ethylene-methacrylate copolymer, ethylene-butyl acrylate copolymer, acrylonitrile-butadiene-styrene, acrylic-urethane resin, or water-soluble acrylic resin. The above polystyrene resin may be, for example, styrene-butadiene copolymer, styrene-butadiene-styrene copolymer, styrene-acrylonitrile copolymer, or styrene-maleic anhydride copolymer. The types of the above polymer resins are not limited to the examples described above, and the glass transition temperature (T. g ) or softening point, crystallization temperature (T c ) and / or melting point (T m Known materials may be combined in appropriate amounts as long as they are polymer resins capable of satisfying the aforementioned range of features such as ) and do not impede the purpose of the present invention.

[0063] The above polymer resin may additionally include, for example, an inorganic material. The inorganic material may include, for example, a metal oxide, a metal hydroxide, or a combination thereof. Examples of the inorganic material may include Al2O3, Al(OH)3, etc., but are not limited thereto, and any inorganic material usable in the field of all-solid-state secondary batteries may be used.

[0064] The present invention enables the frame structure to comprise a polymer resin having the above-described characteristics, thereby enhancing the effect of substantially eliminating or reducing gaps in a planar direction perpendicular to the stacking direction between the anode layer and the frame structure and / or gaps in the stacking direction between the solid electrolyte layer and the frame structure caused by process tolerances through a pressurization process, and thereby controlling sliding phenomena of the anode layer or short-circuit phenomena caused by bending of the cathode layer and the solid electrolyte layer. These effects can be achieved more effectively through the control of the characteristics described below.

[0065] The frame structure may, for example, surround at least 80% of the total perimeter of the side of the anode layer. In other examples, the frame structure may surround at least 85%, at least 90%, at least 95%, at least 99%, or 100% of the total perimeter of the side of the anode layer. Depending on the case, the frame structure may be introduced to surround the side of the all-solid unit cell in a '□' shape. However, the frame structure may not be formed, for example, in a part where the current collector layer protrudes (e.g., an area where an electrode tab or an electrode-free part exists). When the frame structure is introduced in a form that surrounds the side of the anode layer, the frame structure may extend from one side of the anode layer to the end portion of the solid electrolyte layer. Accordingly, cracks occurring at the end portion of the solid electrolyte layer can be suppressed. In this specification, the end portion of the solid electrolyte layer may, for example, refer to the outermost portion in contact with the side of the solid electrolyte layer. The above frame structure may extend, for example, to the outermost portion in contact with the side of the solid electrolyte layer, but may not come into contact with the cathode layer. The above frame structure may fill a space extending from one side of the anode layer to the end portion of the solid electrolyte layer.

[0066] The frame structure included in the all-solid-state secondary battery of the present invention may be, for example, a single-layer structure or a multi-layer structure. If the frame structure is a multi-layer structure, it may include a plurality of layers, for example, in a stacking direction or in a direction perpendicular to the stacking direction. The multi-layer structure may be, for example, a two-layer structure, a three-layer structure, a four-layer structure, or a five-layer structure. Each layer of the multi-layer structure may independently have the same or different compositions from one another. Preferably, the frame structure may be a single-layer structure or a multi-layer structure including a plurality of layers having the same composition, from the perspective that it must have constant fluidity over the entire surface area of ​​the frame structure when pressurized.

[0067] In the all-solid-state secondary battery of the present invention, for example, when viewed in the stacking direction, the area of ​​the positive electrode layer may be smaller than the area of ​​the solid electrolyte layer. In the all-solid-state secondary battery of the present invention, for example, when viewed in the stacking direction, the area of ​​the positive electrode layer may also be smaller than the area of ​​the negative electrode layer. In the all-solid-state secondary battery of the present invention, for example, when viewed in the stacking direction, the area of ​​the negative electrode layer may be equal to the area of ​​the solid electrolyte layer.

[0068] In the all-solid-state secondary battery of the present invention, when viewed from the stacking direction, the sum of the areas of the positive electrode layer and the frame structure may be equal to or greater than the area of ​​the solid electrolyte layer. In the all-solid-state secondary battery of the present invention, when viewed from the stacking direction, the sum of the areas of the positive electrode layer and the frame structure may be equal to or greater than the area of ​​the negative electrode layer.

[0069] The all-solid-state battery cell of the present invention may be, for example, a monocell, a bicell, or a multistack cell. The monocell refers to a unit cell in which the types of electrodes located on both sides are different in a structure in which one or more positive layers and one or more negative layers are stacked with a solid electrolyte layer interposed therebetween. The monocell may have a structure in which, for example, a positive layer, a solid electrolyte layer, and a negative layer are sequentially stacked. The bicell refers to a unit cell in which the types of electrodes located on both sides are the same in a structure in which one or more positive layers and one or more negative layers are stacked with a solid electrolyte layer interposed therebetween. The bicell may have a structure in which, for example, a negative layer, a solid electrolyte layer, a positive layer, a solid electrolyte layer, and a negative layer are sequentially stacked, or a structure in which a positive layer, a solid electrolyte layer, a negative layer, a solid electrolyte layer, and a positive layer are sequentially stacked. The multistack cell itself refers to a cell having a stacked structure in which a structure in which a solid electrolyte layer is interposed between a positive layer and a negative layer is repeated three or more times.

[0070] The all-solid-state battery cell or battery laminate of the present invention may have a structure such as a wound type, a stack type, a stack and folding type, or a lamination / stack type, but is not limited thereto.

[0071] The anode layer of the present invention may include, for example, an anode composite layer and / or an anode current collector layer. The anode layer may be, for example, a double-sided anode layer in which an anode composite layer is formed on both sides of an anode current collector layer, or a single-sided anode layer in which an anode composite layer is formed on one side of an anode current collector layer. In some cases, the anode layer may not include an anode current collector layer.

[0072] The above-mentioned anode composite layer may be, for example, an anode active material layer. The above-mentioned anode active material layer may include, for example, an anode active material, a conductive material, a binder, and / or a solid electrolyte, and may additionally include additives in some cases.

[0073] The above-mentioned positive electrode active material may include, for example, one or more selected from the group consisting of lithium transition metal oxides, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, and vanadium oxide. The lithium transition metal oxide may be lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganese oxide (lithium manganate), or lithium iron phosphate, or a combination thereof. The positive electrode active material is not limited thereto and may be any material used as a positive electrode active material in the relevant technical field. Each positive electrode active material may be used individually or in a mixture of two or more types.

[0074] The above lithium transition metal oxide is, for example, Li a A 1-b B bD2 (wherein 0.90≤a≤1, and 0≤b≤0.5); Li a Ni 1-b-c Co b B c O 2-α F2(wherein 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0 <α<2); Li a Ni 1-b-c Mn b B c D α (In the above formula, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0≤α≤2); Li a Ni 1-b-c Co b B c D α (In the above formula, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2); Li a E 1-b B b O 2-c D c (In the above formula, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05); LiE 2-b B b O 4-c D c (In the above formula, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b B c O 2-α F α (In the above formula, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a CoG b O2(wherein the above formula, 0.90≤a≤1, 0.001≤b≤0.1); Li a MnG b O2(wherein the above formula, 0.90≤a≤1, 0.001≤b≤0.1); Li a Mn2G b O4(wherein the above formula, 0.90≤a≤1, 0.001≤b≤0.1); Li a Ni 1-b-c Mn b B cO 2-α F α (In the above formula, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a Ni 1-b-c Mn b B c O 2-α F2(wherein 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a Ni b E c G d O2(wherein 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1); Li a Ni b Co c Mn d G e O2(wherein the above equation, 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0 ≤d≤0.5, 0.001≤e≤0.1); Li a NiG b O2 (wherein the above equation, 0.90≤a≤1, 0.001≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiIO2; LiNiVO4; Li (3- f) J2(PO4)3(0≤f≤2); Li (3-f)Fe2(PO4)3(0≤f≤2); it may be a compound represented by any one of the chemical formulas of LiFePO4. In such a compound, A is Ni, Co, Mn, or a combination thereof; B 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; E is Co, Mn, or a combination thereof; F is 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; I is Cr, V, Fe, Sc, Y, or a combination thereof; and J may be V, Cr, Mn, Co, Ni, Cu, or a combination thereof. As a positive electrode active material, a compound having a coating layer added to the surface of such a compound may be used, or a mixture of the compound described above and the compound having a coating layer added may be used. A coating layer added to the surface of such compounds may contain, for example, a lithium ion conductive oxide. The lithium ion conductive oxide is, for example, LiNbO3, Li4Ti5O 12 Examples include Li3PO4, but are not limited thereto. The compounds forming this coating layer may be amorphous or crystalline. Methods for forming the coating layer may include, for example, spray coating or immersion methods, but can be selected without limitation as long as they do not adversely affect the physical properties of the cathode active material.

[0075] When the above-mentioned cathode active material contains nickel (Ni) as a ternary lithium transition metal oxide such as NCA or NCM, for example, it may be possible to increase the capacity density of the all-solid-state secondary battery and reduce the metal leaching of the cathode active material in the charged state. Accordingly, the cycle characteristics of the all-solid-state secondary battery in the charged state may be improved.

[0076] The shape of the above-mentioned positive electrode active material may be a particle shape such as a sphere, elliptical sphere, etc. The particle size of the positive electrode active material is not particularly limited and must be within a range applicable to the positive electrode active material of a conventional all-solid-state secondary battery. The content of the positive electrode active material is also not particularly limited and must be within a range applicable to the positive electrode of a conventional all-solid-state secondary battery.

[0077] The above conductive material is not particularly limited as long as it possesses conductivity without causing chemical changes in the battery; specifically, graphite, carbon-based materials, metal powder or metal fiber, needle-shaped or branched conductive whiskers, conductive metal oxides, conductive polymers, and any one of these or a mixture thereof may be used. More specifically, graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, carbon fiber; metal powder or metal fiber such as copper, nickel, aluminum, or silver; needle-shaped or branched conductive whiskers such as zinc oxide whiskers, calcium carbonate whiskers, titanium dioxide whiskers, silicon oxide whiskers, silicon carbide whiskers, aluminum borate whiskers, magnesium borate whiskers, potassium titanate whiskers, silicon nitride whiskers, silicon carbide whiskers, and alumina whiskers; Examples include conductive metal oxides such as titanium oxide, or conductive polymers such as polyphenylene derivatives, and any one or more of these may be used.

[0078] The above-mentioned anode binder is any one selected from the group consisting of N,N-bis[3-(triethoxysilyl)propyl]urea, polyethylene oxide (PEO), poly(vinylidene fluoride) (PVDF), and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP), or a mixture of two or more of these; N,N-bis[3-(triethoxysilyl)propyl]urea, polyethylene oxide (PEO), poly(vinylidene fluoride) (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP); conjugated diene rubber latex such as acrylonitrile-based styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), methyl butadiene methacrylate rubber (MBR), and butadiene rubber (BR); carboxymethylcellulose (CMC). It may be any one selected from the group consisting of starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene (PTFE), polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, various copolymers, etc., or a mixture of two or more of these.

[0079] The solid electrolyte included in the anode composite layer may be, for example, the same or different from the solid electrolyte included in the solid electrolyte layer and / or the cathode active material layer described later. The solid electrolyte included in the anode composite layer may, for example, have a smaller average particle size compared to the solid electrolyte included in the solid electrolyte layer described later. For example, the average particle size of the solid electrolyte included in the anode composite layer may be 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, or 20% or less of the average particle size of the solid electrolyte included in the solid electrolyte layer.

[0080] The above-mentioned anode composite layer may further include additives such as fillers, coating agents, dispersants, and ion conductivity aids. Known materials generally used in electrodes of all-solid-state secondary batteries may be used as the fillers, coating agents, dispersants, ion conductivity aids, etc. that the anode composite layer may include.

[0081] The above positive current collector layer is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and may include, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or a surface treated with carbon, nickel, titanium, silver, etc. on the surface of aluminum or stainless steel.

[0082] The above solid electrolyte layer may be characterized by including, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a polymer-based solid electrolyte. From the perspective of improving ion conductivity, it may be preferable for the above solid electrolyte layer to be a sulfide-based solid electrolyte.

[0083] The above sulfide-based solid electrolyte is, for example, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are positive numbers, M is one of P, Si, Ge, B, Al, Ga, and In), Li2S-SiS2-P2S5-LiI, Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element), Li2S-B2S3, Li2S-P2S5-Z m S n (m, n are positive numbers), Z is one of Ge, Zn, or Ga, L i2 S-GeS2, Li 7-x PS 6-x Cl x(0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2) and Li 7-x PS 6-x I x It may be one or more selected from (0≤x≤2). Sulfide-based solid electrolytes can be manufactured by processing starting materials, such as Li2S or P2S5, by methods such as melt quenching or mechanical milling. Additionally, heat treatment may be performed after such processing. The solid electrolyte may be amorphous, crystalline, or a mixture thereof. In the present invention, the sulfide-based solid electrolyte may, for example, include sulfur (S), phosphorus (P), and lithium (Li) as at least constituent elements among the above-mentioned sulfide-based solid electrolyte materials.

[0084] The above sulfide-based solid electrolyte is, for example, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x It may be an argyrodite-type compound comprising one or more selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound comprising one or more selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0085] The density of the above-mentioned azyrodite-type solid electrolyte may be, for example, 1.5 to 2.0 g / cc. Since the above-mentioned azyrodite-type solid electrolyte has a density of 1.5 g / cc or higher, the internal resistance of the all-solid-state secondary battery is reduced, and penetration of the solid electrolyte by Li can be effectively suppressed.

[0086] The elastic modulus of the above sulfide-based solid electrolyte may be, for example, 15 to 35 GPa.

[0087] The above oxide-based solid electrolyte may contain oxygen (O) and have the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table. For example, LLTO-based compounds, Li6La2CaTa2O 12 , Li6La2ANb2O 12 (A is Ca or Sr), Li2Nd3TeSbO 12 , Li3BO 2.5 N 0.5 , Li9SiAlO8, LAGP-based compounds, LATP-based compounds, Li1 +x Ti 2-x Al x Si y (PO4) 3-y (where, 0≤x≤1, 0≤y≤1), LiAl x Zr 2-x (PO4)3(where, 0≤x≤1, 0≤y≤1), LiTi x Zr 2-x It may include one or more selected from (PO4)3 (wherein, 0≤x≤1, 0≤y≤1), LISICON-based compounds, LIPON-based compounds, perovskite-based compounds, Nasicon-based compounds and LLZO-based compounds.

[0088] The above-mentioned polymer-based solid electrolyte is a composite of a lithium salt and a polymer resin, that is, a polymer electrolyte material formed by adding a polymer resin to a solvated lithium salt, approximately 1 x 10⁻⁶ -7 S / cm or more, preferably about 1x10 -5 It can exhibit ionic conductivity greater than S / cm.

[0089] Non-limiting examples of the polymer resin for the solid electrolyte above include polyether-based polymers, polycarbonate-based polymers, acrylate-based polymers, polysiloxane-based polymers, phosphazene-based polymers, polyethylene derivatives, alkylene oxide derivatives such as polyethylene oxide, phosphate ester polymers, polyagitation lysine, polyester sulfides, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionic dissociators, etc., and may include one or more of these. In addition, as a polymer resin, the polymer electrolyte above may include branched copolymers, comb-like polymers, and cross-linked polymer resins, etc., in which amorphous polymers such as PMMA, polycarbonate, polysiloxane (PDMS), and / or phosphazene are copolymerized as comonomers on a polyethylene oxide (PEO) main chain, and may include one or more of these.

[0090] The aforementioned lithium salt is an ionizable lithium salt, Li + X - It can be expressed as. The anion of such lithium salts is not particularly limited, but F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH -, (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - , (CF3CF2SO2)2N - Examples of the back can be given.

[0091] The above-mentioned solid electrolyte layer may include, for example, a binder. The binder included in the solid electrolyte layer may be, for example, one of the types of binders included in the anode composite layer and / or cathode composite layer disclosed in the present invention, but is not limited thereto and any binder used in the art may be possible. The binder included in the solid electrolyte layer may be the same as or different from the binder included in the anode composite layer and / or cathode composite layer disclosed in the present invention.

[0092] The above cathode layer may include, for example, a cathode composite layer and / or a cathode current collector layer. The above cathode layer may be, for example, a double-sided cathode layer in which a cathode composite layer is formed on both sides of a cathode current collector layer, or a single-sided cathode layer in which a cathode composite layer is formed on one side of a cathode current collector layer. In some cases, the above cathode layer may not include a cathode current collector layer.

[0093] The above cathode composite layer may be, for example, a cathode active material layer or a non-cathode coating layer.

[0094] The above-mentioned cathode active material layer may include, for example, a cathode active material, a conductive material, a binder, and / or a solid electrolyte, and may additionally include additives in some cases.

[0095] The above-mentioned negative electrode active material may include, for example, lithium metal, lithium alloy, lithium metal composite oxide, lithium-containing titanium composite oxide (LTO), silicon, silicon alloy, and combinations thereof. Here, the lithium alloy may be an alloy composed of lithium and at least one metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al, and Sn. The lithium metal composite oxide may be an oxide (MeOx) of any one metal (Me) selected from the group consisting of lithium, Si, Sn, Zn, Mg, Cd, Ce, Ni, and Fe, and in one example, Li x Fe2O3(0 <x≤1) 또는 Li x WO2(0 <x≤1)일 수 있다. 음극활물질은 또한 예를 들어 Sn x Me 1-x Me y O z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, Group 1, 2, and 3 elements of the periodic table, halogens; 0 <x≤1; 1≤y≤3; 1≤z≤8) 등의 금속 복합 산화물; SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4및 Bi2O5등의 산화물 등을 포함할 수 있고, 결정질 탄소, 비정질 탄소 또는 탄소 복합체와 같은 탄소계 음극활물질이 단독으로 또는 2종 이상이 포함될 수 있다.

[0096] Examples of the above conductive materials include nickel powder, cobalt oxide, titanium oxide, carbon, etc. As for carbon, any one selected from the group consisting of Ketjen black, acetylene black, furnace black, graphite, carbon fiber, and fullerene, or one or more of these may be cited.

[0097] The above-mentioned cathode binder is, for example, any one selected from the group consisting of N,N-bis[3-(triethoxysilyl)propyl]urea, polyethylene oxide (PEO), poly(vinylidene fluoride) (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP), conjugated diene rubber latex such as styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), methyl butadiene methacrylate rubber (MBR), and butadiene rubber (BR), carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, and various copolymers, or a mixture of two or more of these. It is possible.

[0098] The solid electrolyte included in the negative electrode active material layer may be the same as or different from the solid electrolyte included in the aforementioned positive electrode active material layer and / or solid electrolyte layer, etc.

[0099] In this specification, the term "non-cathode coating layer" refers to a coating layer formed between a negative electrode current collector and a solid electrolyte layer in an all-solid-state secondary battery in which lithium is adsorbed in the non-cathode coating layer during charging and, after the charging capacity of the non-cathode coating layer is exceeded, lithium is precipitated between the negative electrode current collector and the non-cathode coating layer to form a metal layer, and during discharge, lithium in the non-cathode coating layer and the lithium metal layer is ionized and moves toward the positive electrode. The composition and operating mechanism may differ from the aforementioned negative electrode active material layer. The non-cathode coating layer can cover the lithium metal layer during the charging process and / or immediately after battery manufacturing to serve as a protective layer for the lithium metal layer and can suppress the precipitation growth of lithium dendrites. Through this, short circuits and capacity degradation of the all-solid-state secondary battery can be suppressed and performance, etc., improved.

[0100] The above-mentioned anode coating layer may include, for example, amorphous carbon. The amorphous carbon included in the above-mentioned anode coating layer may be, for example, one or more types selected independently from the group consisting of carbon black, acetylene black, furnace black, Ketjen black, and graphene, but is not limited thereto, and any amorphous carbon that can be used in an anode all-solid-state secondary battery may be used without limitation.

[0101] The above-mentioned non-cathode coating layer may further include, for example, a lithium-affinity element that forms an alloy or compound with lithium. The lithium-affinity element may be, for example, one or more metals, metalloids, or combinations thereof selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn).

[0102] The particle size of the above lithium-affinity element may be, for example, within a range of 10 to 1000 nm. The above particle size may refer to a maximum particle size, a minimum particle size, or an average particle size. In other examples, the particle size of the above lithium-affinity element may be 20 nm or more, 30 nm or more, 40 nm or more, or 50 nm or more, or 500 nm or less, 400 nm or less, 300 nm or less, 200 nm or less, or 100 nm or less.

[0103] The above-mentioned non-cathode coating layer may also further include, for example, a binder. The binder for the above-mentioned non-cathode coating layer may be selected from the binders mentioned as being included in the aforementioned anode composite layer, cathode active material layer, and solid electrolyte layer, etc., or any known binder may be used without limitation without being limited thereto.

[0104] When an all-solid-state secondary battery includes a negative electrode coating layer, the all-solid-state secondary battery may further include a thin film containing an element capable of forming an alloy with lithium, for example. The thin film may be included between the negative electrode current collector and the negative electrode coating layer. The element capable of forming an alloy with lithium may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., but is not limited thereto; any element capable of forming an alloy with lithium in the relevant technical field may be used. The thin film may be composed of one of the above examples or may be composed of various types of alloys. As the all-solid-state secondary battery of the present invention further includes such a thin film, the cycle characteristics of the all-solid-state secondary battery may be further improved.

[0105] The thickness of the thin film may be, for example, 1 to 800 nm, 10 to 700 nm, 50 to 600 nm, or 100 to 500 nm. The thin film may be formed by, for example, vacuum deposition, sputtering, plating, etc., but is not limited thereto, and any method capable of forming a thin film in the relevant technical field is possible.

[0106] When including the above-mentioned anode coating layer, the all-solid-state secondary battery may further include, for example, a metal comprising lithium or a lithium alloy and / or a metal layer thereof between the negative electrode current collector and the anode coating layer, on the side of the anode coating layer opposite to the solid electrolyte layer, and / or within the anode coating layer. The lithium alloy may be, for example, Li-Al alloy, Li-Sn alloy, Li-In alloy, Li-Ag alloy, Li-Au alloy, Li-Zn alloy, Li-Ge alloy, Li-Si alloy, etc., but is not limited thereto; any alloy used as a lithium alloy in the relevant technical field is acceptable. The metal or metal layer included between the negative electrode current collector and the anode coating layer and / or within the anode coating layer may be composed of one of these alloys or lithium, or may be composed of various types of alloys.

[0107] The thickness of the metal layer containing the lithium or lithium alloy may be, for example, within a range of 1 to 1000 μm, 1 to 500 μm, 1 to 200 μm, 1 to 150 μm, 1 to 100 μm, or 1 to 50 μm. It is necessary to control the thickness as above so that the metal layer can perform its role as a lithium reservoir effectively and improve cycle characteristics.

[0108] The above metal layer may be formed, for example, by precipitation between the negative electrode current collector and the non-negative electrode coating layer, or on the side of the non-negative electrode coating layer opposite to the solid electrolyte layer, through charging after assembly of the all-solid-state secondary battery. When the metal layer is formed by charging after assembly of the all-solid-state secondary battery, the region between the negative electrode current collector and the non-negative electrode coating layer, or on the side of the non-negative electrode coating layer opposite to the solid electrolyte layer, may, for example, be a lithium-free region that does not contain lithium in the initial state or after discharge of the all-solid-state secondary battery. In another example, the above metal layer may be placed between the non-negative electrode coating layer and the negative electrode current collector during battery manufacturing, where lithium in the non-negative electrode coating layer and the lithium metal layer is ionized and moves toward the positive electrode during discharge, and is formed by lithium being precipitated again between the negative electrode current collector and the non-negative electrode coating layer after the charging capacity of the non-negative electrode coating layer is exceeded during charging.

[0109] Examples of additives that may be included in the above-mentioned cathode composite layer include fillers, coating agents, dispersants, and ion conductivity aids. Known materials generally used in electrodes of all-solid-state secondary batteries may be used as fillers, coating agents, dispersants, and ion conductivity aids that may be included in the cathode composite layer.

[0110] The above-mentioned negative current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and may include, for example, stainless steel, copper, nickel, titanium, calcined carbon, or stainless steel surface treated with carbon, nickel, titanium, silver, etc.

[0111] The above-described all-solid-state secondary battery may further include, for example, a buffer layer. The buffer layer may further include, for example, at least one of the upper and / or lower portions in the stacking direction of the aforementioned monocell, bicell, and / or multi-stack cell. In another example, when the all-solid-state secondary battery comprises a plurality of monocells, bicells, and / or multi-stack cells, the buffer layer may include at least one portion between adjacent cells, etc.

[0112] The above buffer layer may include, for example, an elastic material.

[0113] The above elastic material may include, but is not limited to, polyurethane, polyacrylate, fluorinated polymer, natural rubber, spandex, butyl rubber (or halogenated butyl rubber), fluoroelastomer, elastomer, ethylene-propylene rubber (EPR), styrene-butadiene rubber (SBR), isoprene rubber, polybutadiene, nitrile rubber, thermoplastic elastomer, silicone rubber, ethylene-propylene-diene rubber (EPDM), ethylene vinyl acetate (EVA), neoprene (or chloroprene), acrylic, copolymers thereof, or combinations thereof, and may be used without limitation as long as it is an elastic material that does not impede the purpose of the present invention.

[0114] The above buffer layer may be in the shape of a sheet or a plate, or a rectangular shape when viewed from a planar perspective. The thickness direction of the buffer layer may coincide with the stacking direction of the unit cell.

[0115] The above buffer layer may be, for example, a porous polymer foam, a porous polymer sponge, or rubber, but is not limited thereto. Any material having elasticity and resilience that is used in the industry as long as it does not impede the purpose of the present invention may be used without limitation.

[0116] The second aspect of the present invention relates to a method for manufacturing an all-solid-state secondary battery. The details regarding the first aspect of the present invention may be applied in the same way to the details regarding the second aspect unless specifically described otherwise.

[0117] The present invention relates to a method for manufacturing an all-solid-state secondary battery having a battery stack having one or more all-solid-state battery cells stacked therein, wherein the all-solid-state battery cell comprises one or more positive electrode layers, a solid electrolyte layer, and a negative electrode layer, and may include the step of introducing a frame structure on the side of the positive electrode layer (step S1); and / or the step of pressing the all-solid-state battery cell (step S2), and the gap in a planar direction perpendicular to the stacking direction between the positive electrode layer and the frame structure may be 50 μm or less.

[0118] The above S1 step can be performed, for example, before the S2 step.

[0119] The glass transition temperature (T) of the above polymer resin g The glass transition temperature (T) or softening point may preferably be below the pressurization temperature in that it can substantially eliminate or reduce the gap between the frame structure and the anode layer or the gap between the frame structure and the solid electrolyte layer existing prior to the pressurization process. g ) or if the softening point is below the pressurization temperature, the polymer resin for the frame structure changes into a viscous, soft state during the pressurization process, and thus the empty space between the frame structure and the anode layer or solid electrolyte layer can be substantially eliminated or reduced by the pressurization process.

[0120] In the above pressurization step (step S2), the pressurization pressure and pressurization time may each be the pressurization pressure and pressurization time typically used in the manufacture of all-solid-state batteries. In the above pressurization step (step S2), the pressurization pressure may be, for example, 300 to 700 MPa. The pressurization pressure may be the same or different throughout the pressurization process, for example. In the above pressurization step (step S2), the pressurization time may be, for example, 1 minute to 30 minutes.

[0121] The step of introducing the above-mentioned frame structure (step S1) may, for example, involve introducing and curing a polymer resin composition to form the frame structure. When forming the frame structure by introducing and curing a polymer resin composition, for example, a dispenser may be used to melt the polymer resin composition and form a desired shape. The above-mentioned polymer resin composition may include, for example, the aforementioned polymer resin and / or the curable resin described below. The curable resin may be, for example, a thermosetting resin or a photocurable resin. The above-mentioned thermosetting resin may include, for example, one or more selected from the group comprising epoxy resin, phenolic resin, melamine resin, urea-formaldehyde resin, polyester resin, silicone resin, polyurethane resin, vinyl ester resin, polyimide resin, and novolak resin. The above-mentioned photocurable resin may be, for example, an acrylate-based resin, such as epoxy acrylate resin, urethane acrylate resin, polyester acrylate resin, silicone acrylate resin; cationic epoxy resin; diolefin-based resin; It may include one or more selected from the group comprising photoresist and bio-based photocurable resin. In other examples, the step of introducing the frame structure (step S1) may be to form the frame structure and then introduce it to the side of the anode layer. The frame structure may be, for example, in the form of a film, sheet, or gasket. The frame structure may be, for example, a structure that surrounds at least a portion of the perimeter of the side of the anode layer.

[0122] In the present invention, the gap in the planar direction perpendicular to the stacking direction between the anode layer and the frame structure may be smaller after the step of pressurizing the all-solid-state battery cell than before the step of pressurizing the all-solid-state battery cell. As the frame structure becomes fluid due to the pressurization process, the gap in the planar direction perpendicular to the stacking direction between the anode layer and the frame structure and / or the gap in the stacking direction between the solid electrolyte layer and the frame structure may be substantially eliminated or reduced.

[0123] In the present invention, after the step of pressurizing the all-solid-state battery cell, the upper end of the positive layer may be located on the same line in the horizontal direction as the upper end of the frame structure, and the lower end of the positive layer may be located on the same line in the horizontal direction as the lower end of the frame structure.

[0124] Even if not specifically described in this specification, methods for manufacturing all-solid-state secondary batteries widely known in the art may be applied without limitation as long as they do not impede the purpose of the present invention.

[0125] In the following, the present invention is described in detail with reference to examples to specifically explain the disclosure of the present invention as described above and the intended functions and effects of the present invention. However, the examples may be modified in various different forms, and the scope of this specification is not to be interpreted as being limited only to these examples. It is emphasized that the examples are provided to represent the present invention and to explain it more specifically to those skilled in the art.

[0126] Example.

[0127] Manufacturing of all-solid-state battery cells

[0128] (Cathode layer)

[0129] 6 g of carbon black (average particle size 41 nm), 2 g of silver (Ag) nanoparticles (average particle size 60 nm), 9.33 g of PVdF solution (solid content 6%), and 7.19 g of NMP solution were placed in a Thinky mixer container and mixed 12 times for 3 minutes at 2000 rpm. Subsequently, 5 g of NMP solution was added, and mixing was performed 5 times for 3 minutes at 2000 rpm to prepare a cathode-free coating layer slurry. Next, the slurry was coated onto a 10 μm thick SUS foil using a bar coater, dried in air at 80°C for 20 minutes, and then vacuum dried at 100°C for 12 hours. Through this process, a cathode layer was obtained in which a cathode-free coating layer with a thickness of 14.0 μm and a porosity of 67.1% was formed on the SUS foil.

[0130] (Bipolar layer)

[0131] LiNi as the positive active material 0.8 Co 0.15 Mn 0.05 O2 (NCM), Li6PS5Cl, an Argyrodite-type crystal, as the solid electrolyte, polytetrafluoroethylene (Teflon binder, DuPont) as the binder, and carbon nanofiber (CNF) as the conductive material were prepared. Then, these materials were mixed in a weight ratio of positive active material : solid electrolyte : conductive material : binder = 83.8 : 14.8 : 0.2 : 1.2, and the mixture was formed into a large sheet to produce a positive composite layer. Subsequently, this positive composite layer was pressed onto both sides of a 10 μm thick aluminum foil positive current collector to produce a positive layer.

[0132] (Solid electrolyte layer)

[0133] The solid electrolyte layer used contained Li6PS5Cl solid electrolyte.

[0134] (All-solid-state battery cell)

[0135] A cathode layer (2), a solid electrolyte layer (3), an anode layer (1), a solid electrolyte layer (3), and a cathode layer (2) were sequentially stacked, and a frame structure (4) was introduced to surround the anode layer. As the frame structure, polypropylene (PP) with a softening point of 78°C was used, formed into a '□' shape when viewed from the stacking direction. The anode layer was placed in the center of the solid electrolyte layer, and the frame structure was placed to surround the anode layer and extend to the end portion of the solid electrolyte layer. The area of ​​the anode layer was approximately 90% of the area of ​​the solid electrolyte layer, and the frame structure was placed in the remaining 10% of the area of ​​the solid electrolyte layer where the anode layer was not placed. Before isotropic pressurization treatment, the gap (5) in the planar direction perpendicular to the stacking direction between the anode layer and the frame structure was approximately 80 μm (see FIG. 3).

[0136] After sealing the prepared all-solid unit cell in a pouch under vacuum, it was subjected to isotropic pressurization at 500 MPa at approximately 80°C for 30 minutes. Since polypropylene (PP) with a softening point of 78°C was used as the frame structure, the frame structure could have fluidity at the isotropic pressurization temperature. Accordingly, it was possible to manufacture an all-solid battery cell in which the gap (5) in the plane direction perpendicular to the stacking direction between the anode layer and the frame structure was zero (see FIG. 3). Meanwhile, the solid electrolyte layer was sintered by the isotropic pressurization treatment, and the battery characteristics were also improved, and the thickness of the sintered solid electrolyte layer was approximately 50 μm. The area of ​​the solid electrolyte layer was the same as the area of ​​the negative electrode layer.

[0137] Manufacturing of all-solid-state secondary batteries

[0138] After completing the isotropic pressurization treatment, one all-solid-state unit cell was prepared by removing the pouch. The all-solid-state unit cell was placed in a pouch and vacuum-sealed to manufacture an all-solid-state secondary battery. Parts of the positive electrode current collector and the negative electrode current collector were protruded outside the sealed battery and used as positive layer terminals and negative layer terminals.

[0139] Comparative example.

[0140] A solid-state secondary battery was manufactured in the same manner as in the example, except that polypropylene (PP) with a softening point of 90°C was used as the frame structure. Before isotropic pressurization treatment, the gap (5) in the planar direction perpendicular to the stacking direction between the anode layer and the frame structure was approximately 73 μm.

[0141] The prepared all-solid unit cell was sealed in a pouch under vacuum and then subjected to isotropic pressurization at 500 MPa at approximately 80°C for 30 minutes. In the comparative example, unlike the example, the gap (5) in the plane direction perpendicular to the stacking direction between the anode layer and the frame structure was approximately 55 μm even after isotropic pressurization. Therefore, in the comparative example, unlike the example, it was confirmed that a gap still existed between the anode layer and the frame structure after isotropic pressurization (see FIG. 4).

[0142] Evaluation example. Measurement of the gap (5) in a plane direction perpendicular to the stacking direction between the anode layer and the frame structure.

[0143] After attaching the anode layer-frame structure portion of the all-solid unit cell of the example and comparative example onto a slide glass, the gap (5) in the plane direction perpendicular to the stacking direction between the anode layer and the frame structure was measured using an illuminance meter (Keyence VK-X160K). The illuminance measurement results of the example and comparative example are shown in FIGS. 3 and FIGS. 4, respectively. In FIGS. 3 and FIGS. 4, the results of measuring illuminance along the arrow in the left image are shown in the graph on the right. As a result, unlike the comparative example, in the example, the gap (5) in the plane direction perpendicular to the stacking direction between the anode layer and the frame structure was about 80 μm before isotropic pressing, but became 0 μm after isotropic pressing, so the gap between the anode layer and the frame structure was eliminated.

[0144] [Explanation of the symbol]

[0145] 1: Anode layer

[0146] 2: Cathode layer

[0147] 3: Solid electrolyte layer

[0148] 4: Frame structure

[0149] 5: Gap in the planar direction perpendicular to the stacking direction between the anode layer and the frame structure

[0150] 6: Gap in the stacking direction between the solid electrolyte layer and the frame structure

Claims

1. An all-solid-state secondary battery comprising a battery stack having one or more all-solid-state battery cells stacked therein, The above-described all-solid-state battery cell comprises one or more each of a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, and It includes a frame structure that surrounds at least a portion of the lateral perimeter of the anode layer, and All-solid-state secondary battery having a gap of 50 μm or less in a planar direction perpendicular to the stacking direction between the anode layer and the frame structure.

2. In Paragraph 1, The above-described frame structure comprises a polymer resin satisfying the following condition 1, an all-solid-state secondary battery: [Condition 1] Glass transition temperature (T) of polymer resin g ) or softening point ≤ pressurized temperature.

3. In Paragraph 2, The above-mentioned pressurization temperature is an isotropic pressurization temperature, for an all-solid-state secondary battery.

4. In Paragraph 1, The above frame structure has a glass transition temperature (T g An all-solid-state secondary battery comprising a polymer resin having a softening point of 200°C or lower.

5. In Paragraph 1, The above frame structure has a crystallization temperature (T c All-solid-state secondary battery comprising a polymer resin with a pressure temperature greater than the pressure temperature.

6. In Paragraph 1, The above frame structure comprises a polymer resin, and The above polymer resin comprises one or more types selected from the group consisting of polyolefin resin, fluorine resin, cellulose resin, epoxy resin, vinyl resin, acrylic resin, and polystyrene resin, an all-solid-state secondary battery.

7. In Paragraph 1, An all-solid-state secondary battery in which the above-described frame structure surrounds at least 80% of the entire perimeter of the side of the anode layer.

8. In Paragraph 1, A solid-state secondary battery in which the upper portion of the anode layer is located on the same plane as the upper portion of the frame structure and the lower portion of the anode layer is located on the same plane as the lower portion of the frame structure.

9. In Paragraph 1, All-solid-state secondary battery in which the above-mentioned frame structure is a single-layer or multi-layer structure.

10. In Paragraph 1, When viewed from the stacking direction, All-solid-state secondary battery in which the area of ​​the anode layer is smaller than the area of ​​the solid electrolyte layer.

11. In Paragraph 1, When viewed from the stacking direction, All-solid-state secondary battery in which the sum of the areas of the anode layer and the frame structure is equal to or greater than the area of ​​the solid electrolyte layer.

12. In Paragraph 1, The above-mentioned all-solid-state battery cell is an all-solid-state secondary battery that is a monocell, bicell, or multistack cell.

13. A method for manufacturing an all-solid-state secondary battery comprising a battery stack having one or more all-solid-state battery cells stacked therein, The above-described all-solid-state battery cell comprises one or more each of a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, and A step of introducing a frame structure on the side of the anode layer; and The method includes the step of pressurizing the above-mentioned all-solid-state battery cell, A method for manufacturing an all-solid-state secondary battery, wherein the gap in a plane direction perpendicular to the stacking direction between the anode layer and the frame structure is 50 μm or less.

14. In Paragraph 13, A method for manufacturing an all-solid-state secondary battery, wherein the above-described frame structure comprises a polymer resin satisfying the following condition 1: [Condition 1] Glass transition temperature (T) of polymer resin g ) or softening point ≤ pressurized temperature.

15. In Paragraph 13, The step of introducing a frame structure to the side of the anode layer is, A frame structure is formed by introducing and curing a polymer resin composition, or A method for manufacturing an all-solid-state secondary battery, wherein a frame structure is formed and then introduced to the side of the anode layer.

16. In Paragraph 13, A method for manufacturing an all-solid-state secondary battery, wherein the gap in a plane direction perpendicular to the stacking direction between the anode layer and the frame structure is smaller after the step of pressurizing the all-solid-state battery cell than before the step of pressurizing the all-solid-state battery cell.

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