All-solid-state battery structure and manufacturing method therefor

Abstract

The present invention relates to an all-solid-state battery structure and a manufacturing method therefor, the structure comprising: a pressing jig including first and second plates facing each other; an all-solid-state battery interposed between the first and second plates; and a pad positioned between the first plate and the all-solid-state battery and / or between the second plate and the all-solid-state battery, wherein the pad sequentially includes a first pad and a second pad having different hardnesses, the second pad being closer than the first pad to the all-solid-state battery, and the ratio of Shore A hardness of the second pad to Shore A hardness of the first pad is 1.8 to 5. Pressurization can be uniform and all-solid-state battery damage is controlled while interfacial resistance between layers is lowered, and thus an all-solid-state battery structure having excellent discharge capacity characteristics, high-rate discharge efficiency and cycle performance, and a manufacturing method therefor can be provided.

Description

All-solid-state battery structure and method for manufacturing the same

[0001] The present invention relates to an all-solid-state battery structure and a method for manufacturing the same. The present application claims the benefit of priority based on Korean Patent Application No. 2024-0174034 filed on November 28, 2024, and all contents disclosed in the document of said Korean patent application are incorporated herein as part of the specification.

[0002] Unlike conventional rechargeable batteries that use flammable liquid electrolytes, all-solid-state batteries utilize solid electrolytes, resulting in higher safety due to a lower risk of fire or explosion. Furthermore, they offer excellent usability and durability as they are less likely to experience leakage or oxidation caused by temperature changes or external impacts.

[0003] Despite these advantages, due to the characteristics of all-solid-state batteries that use a solid electrolyte instead of a liquid electrolyte, the interfacial resistance between the anode layer, solid electrolyte layer, and cathode layer is high. This prevents metal ions (e.g., lithium ions) from moving effectively along the contact interfaces, resulting in a problem where the battery fails to perform properly.

[0004] To address this, a technology has been proposed in which an all-solid-state battery is secured to a pressure jig and charged / discharged under pressure; however, due to reasons such as uneven pressure or damage to the all-solid-state battery caused by the pressure jig, problems such as short circuits or deterioration of cycle characteristics have occurred.

[0005] The present invention aims to solve the above problem by providing an all-solid-state battery structure and a method for manufacturing the same, which have excellent discharge capacity characteristics as well as high-rate discharge efficiency and cycle performance, by applying pressure to the all-solid-state battery with a pressure jig to lower interlayer interface resistance while applying pressure uniformly without damaging the all-solid-state battery.

[0006] In one embodiment, the present invention may relate to a solid-state battery structure comprising: a pressure jig including first and second plates arranged to face each other; a solid-state battery interposed between the first and second plates; and a pad located at least one of the distance between the first plate and the solid-state battery and the distance between the second plate and the solid-state battery, wherein the pad sequentially includes a first pad and a second pad, the second pad being positioned closer to the solid-state battery than the first pad, and the ratio of the Shore A hardness of the second pad to the Shore A hardness of the first pad being 1.8 to 5.

[0007] In one embodiment, the thickness ratio of the second pad to the first pad may be 2 or more.

[0008] In one embodiment, the thickness of the first pad may be 0.05 mm to 2 mm.

[0009] In one embodiment, the thickness of the second pad may be 0.6 mm to 5 mm.

[0010] In one embodiment, the Shore A hardness of the first pad may be 30 to 50.

[0011] In one embodiment, the Shore D hardness of the second pad may be 50 to 70.

[0012] In one embodiment, the stress measured during a 50% compression force deflection test of the first pad may be 8.0 MPa or less.

[0013] In one embodiment, the first pad may include one or more selected from the group consisting of thermoplastic elastomer (TPE), TPV (thermoplastic unsaturated rubber), silicone, polyurethane (PU), ethylene propylene diene monomer (EPDM), chloroprene rubber (CR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR), fluorinated rubber (FKM), and combinations thereof.

[0014] In one embodiment, the second pad may include one or more selected from the group consisting of polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polyether ether ketone (PEEK), and combinations thereof.

[0015] In one embodiment, a pad may be located between the first plate and the all-solid-state battery and between the second plate and the all-solid-state battery, respectively.

[0016] In one embodiment, the pressure applied to the all-solid-state battery by the pressure jig may be 1 to 50 MPa.

[0017] In one embodiment, the all-solid-state battery includes an electrode assembly and a case housing the electrode assembly, and the electrode assembly may include at least one monocell, bicell, or multistack cell.

[0018] In one embodiment, the case may be a pouch.

[0019] In one embodiment, the pad and the all-solid-state battery can each be positioned at the center of the pressure jig.

[0020] In one embodiment, the present invention may relate to a method for manufacturing a solid-state battery structure comprising the steps of: introducing a solid-state battery and a pad between a first and second plate of a pressure jig; and arranging the pads such that they are positioned between the first plate and the solid-state battery and between the second plate and the solid-state battery, wherein the pads sequentially include a first pad and a second pad, the second pad is positioned closer to the solid-state battery than the first pad, and the ratio of the Shore A hardness of the second pad to the Shore A hardness of the first pad is 1.8 to 5.

[0021] In one embodiment, a solid-state battery can be introduced with a pad provided on at least one of the inner sides of the first and second plates.

[0022] In one embodiment, the all-solid-state battery can be introduced between the first and second plates while at least one of the two sides of the all-solid-state battery is provided with a pad.

[0023] The present invention can provide an all-solid-state battery structure and a method for manufacturing the same, which have excellent discharge capacity characteristics as well as high-rate discharge efficiency and cycle performance, by pressurizing the all-solid-state battery with a pressurizing jig to lower interlayer interface resistance while uniformly pressurizing without damaging the all-solid-state battery.

[0024] 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.

[0025] FIGS. 1 and FIGS. 2 are schematic diagrams of an all-solid-state battery structure according to an example of the present invention.

[0026] Figure 3 is a graph showing the results of the compressive strain evaluation of pads A and B.

[0027] Figure 4 is a graph showing the discharge capacity evaluation results during one charge and discharge cycle of the examples and comparative examples.

[0028] Figure 5 is a graph showing the discharge capacity evaluation results according to the cycles of the examples and comparative examples.

[0029] Figure 6 is a graph showing the high-rate discharge efficiency evaluation results of the examples and comparative examples.

[0030] FIG. 7 is a flowchart of a method for manufacturing an all-solid-state battery structure according to an example of the present invention.

[0031] 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.

[0032] 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.

[0033] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0034] 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,” so, for example, a “composition comprising compound A” may also be (essentially / essentially) composed of compound A.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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”.

[0039] 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.

[0040] In addition, among the physical properties mentioned in this specification, if the measured pressure affects the physical property, unless otherwise specifically defined, the physical property is measured at atmospheric pressure, that is, at about 1 atmosphere.

[0041] The first aspect of the present invention relates to a battery structure.

[0042] The all-solid-state battery structure of the present invention may include, for example, a pressure jig comprising first and second plates arranged to face each other; an all-solid-state battery interposed between the first and second plates; and / or a pad located at least one of the space between the first plate and the all-solid-state battery and the space between the second plate and the all-solid-state battery. The pad may be detachably attached to, for example, each of the first plate and / or the second plate. The pad may be adhered to, for example, each of the first plate and / or the second plate. When the pad is adhered to the first plate and / or the second plate, the surface of the pad adjacent to the first plate and / or the second plate may have adhesive force. At this time, an adhesive may be applied to the surface of the pad adjacent to the first plate and / or the second plate.

[0043] The all-solid-state battery structure of the present invention can provide an all-solid-state battery structure with excellent discharge capacity characteristics, high-rate discharge efficiency, and cycle performance by enabling uniform pressurization while lowering interlayer interface resistance and controlling all-solid-state battery damage through the inclusion of a pad having the features described below in the all-solid-state battery structure.

[0044] The above pad may sequentially include, for example, a first pad and a second pad. In this specification, the first pad and the second pad may be terms used to distinguish pads with different characteristics, such as hardness and / or material. The first pad and the second pad may, for example, be attached to each other to form a single pad via an adhesive layer, or may be introduced between a pressure jig and an all-solid-state battery in a separated state. The adhesive layer may be, for example, an adhesive commonly used in the industry, and may be used without limitation as long as it does not degrade at a temperature of 60°C or lower.

[0045] In the present invention, the second pad may be positioned closer to the all-solid-state battery than, for example, the first pad. By such a position, it may be possible to provide an all-solid-state battery having excellent performance.

[0046] The first pad and the second pad of the present invention may have different hardnesses from each other, for example. The ratio of the Shore A hardness of the second pad to the Shore A hardness of the first pad may be, for example, about 1.8 to about 5. In this specification, the Shore A hardness may be measured by a method according to ISO 7619-1 or ASTM D2240. The ratio of the Shore A hardness of the second pad to the Shore A hardness of the first pad is, in other examples, about 1.9 or more, about 2.0 or more, about 2.1 or more, about 2.2 or more, about 2.3 or more, about 2.4 or more, or about 2.5 or more, or about 4.9 or less, about 4.8 or less, about 4.7 or less, about 4.6 or less, about 4.5 or less, about 4.4 or less, about 4.3 or less, about 4.2 or less, about 4.1 or less, about 4.0 or less, about 3.9 or less, about 3.8 or less, about 3.7 or less, about 3.6 or less, about 3.5 or less, about 3.4 or less, about 3.3 or less, about 3.2 or less, about 3.1 or less, about 3.0 or less, about 2.9 or less, about 2.8 or less, about 2.7 or less, about 2.6 or less, or about It may be 2.5 or less. The present invention sequentially includes a first pad and a second pad having the ratio of Shore A hardness as described above, and by positioning the second pad closer to the solid-state battery than the first pad, it is possible to provide a solid-state battery structure that maintains the shape of the solid-state battery well while applying sufficient pressure during pressurization, thereby providing excellent discharge capacity characteristics as well as high-rate discharge efficiency and cycle performance. These features can be expressed more effectively by controlling the Shore A hardness and Shore D hardness of the first pad and the second pad, respectively, as described below.

[0047] The Shore A hardness of the first pad may be, for example, about 30 to about 50. In other examples, the Shore A hardness of the first pad may be about 32 or more, 34 or more, 36 or more, 38 or more, or 40 or more, or 48 or less, 46 or less, 44 or less, 42 or less, or 40 or less.

[0048] The Shore D hardness of the second pad may be, for example, about 50 to 70. In this specification, the Shore D hardness may be measured, for example, in the manner according to ISO 868. In other examples, the Shore D hardness of the second pad may be about 52 or more, about 54 or more, about 56 or more, about 58 or more, or about 60 or more, or about 68 or less, about 66 or less, about 64 or less, or about 62 or less.

[0049] The thickness ratio of the second pad to the first pad of the present invention may be, for example, about 2 or more, about 2.5 or more, or about 3 or more, and may be about 20 or less, about 15 or less, about 10 or less, about 9 or less, about 8 or less, about 7 or less, about 6 or less, about 5 or less, or about 4 or less. In this specification, the thickness of the pad may refer, for example, to the thickness when no external force is applied to the pad. The present invention sequentially includes a first pad and a second pad having the hardness characteristics and / or thickness ratio as described above, and by positioning the second pad closer to the all-solid-state battery than the first pad, sufficient pressure can be applied while maintaining the shape of the all-solid-state battery well when pressurized, thereby providing an all-solid-state battery structure with superior discharge capacity characteristics, as well as high-rate discharge efficiency and cycle performance. These characteristics can be more effectively manifested by controlling the thickness of each of the first pad and the second pad as described below.

[0050] The thickness of the first pad may be, for example, about 0.05 mm to about 2 mm. In other examples, the thickness of the first pad may be about 0.5 mm or more, about 0.1 mm or more, about 0.15 mm or more, about 0.2 mm or more, or about 0.25 mm or more, or about 1.5 mm or less, about 1 mm or less, about 0.5 mm or less, about 0.45 mm or less, about 0.4 mm or less, or about 0.35 mm or less.

[0051] The thickness of the second pad may be, for example, about 0.6 mm to about 5 mm. The thickness of the second pad may be about 0.7 mm or more, about 0.8 mm or more, or about 0.9 mm or more, or about 4.5 mm or less, about 4 mm or less, about 3.5 mm or less, about 3 mm or less, about 2.5 mm or less, about 2 mm or less, or about 1.5 mm or less.

[0052] The first pad of the present invention may have a stress of about 8.0 MPa or less when measured, for example, during a 50% compression force deflection (CFD) test. In this specification, the stress measured during an X% compression force deflection test may mean the stress (MPa) measured after compressing by X% and holding for 60 seconds for a new thickness measured, for example, in the manner according to the evaluation example described below, and this may be expressed as CFD X% (X is an integer). The compression force deflection (CFD) may be measured in the manner according to the evaluation example described below. In another example, the first pad of the present invention may have a stress measured during a 50% compression strain test of about 7.8 MPa or less, about 7.6 MPa or less, about 7.4 MPa or less, about 7.2 MPa or less, about 7.0 MPa or less, about 6.8 MPa or less, about 6.6 MPa or less, about 6.4 MPa or less, about 6.2 MPa or less, or about 6.0 MPa or less, or about 0.5 MPa or more, about 1.0 MPa or more, about 1.5 MPa or more, about 2.0 MPa or more, about 2.5 MPa or more, about 3.0 MPa or more, about 3.5 MPa or more, about 4.0 MPa or more, about 4.5 MPa or more, about 5.0 MPa or more, or about 5.5 MPa or more. The first pad above may, for example, have a CFD of 40% of 5 MPa or less, a CFD of 30% of 3.5 MPa or less, a CFD of 20% of 2.4 MPa or less, and / or a CFD of 10% of 1.4 MPa or less, but is not limited thereto.

[0053] The first pad of the present invention may comprise, for example, one or more selected from the group consisting of thermoplastic elastomer (TPE), TPV (thermoplastic unsaturated rubber), silicone, polyurethane (PU), ethylene propylene diene monomer (EPDM), chloroprene rubber (CR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR), fluorinated rubber (FKM), and combinations thereof, but may be used without limitation as long as it satisfies the aforementioned characteristics. Preferably, the first pad of the present invention may comprise silicone in order to have excellent resilience despite repeated compression.

[0054] The second pad of the present invention may comprise, for example, one or more selected from the group consisting of polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polyether ether ketone (PEEK), and combinations thereof, but may be used without limitation as long as it satisfies the aforementioned characteristics. Preferably, the second pad of the present invention may comprise polytetrafluoroethylene (PTFE).

[0055] The all-solid-state battery structure of the present invention may preferably include pads between the first plate and the all-solid-state battery and between the second plate and the all-solid-state battery, respectively, in order to further enhance the effects of the present invention.

[0056] Each of the above pads and all-solid-state batteries may be positioned, for example, at the center of a pressure jig. In this specification, the positioning of each pad and all-solid-state battery at the center of a pressure jig may mean that the center of the pad and the center of the all-solid-state battery are arranged to overlap within an error range with a virtual straight line drawn in the stacking direction from the center of the pressure jig. This allows for more uniform pressure to be applied to the all-solid-state battery, which can contribute to an increase in battery performance.

[0057] The pressure applied to the all-solid-state battery by the above-mentioned pressure jig (also referred to as 'driving pressure') may be, for example, about 1 to about 50 MPa. The pressure applied to the all-solid-state battery by the above-mentioned pressure jig may be about 1 MPa or more, about 2 MPa or more, about 3 MPa or more, about 4 MPa or more, about 5 MPa or more, about 6 MPa or more, about 7 MPa or more, about 8 MPa or more, or about 9 MPa or more, and may be about 50 MPa or less, about 40 MPa or less, about 30 MPa or less, about 20 MPa or less, or about 15 MPa or less, but can be appropriately adjusted according to the size, type, etc. of the all-solid-state battery.

[0058] The all-solid-state battery of the present invention may include, for example, an electrode assembly.

[0059] The electrode assembly described above may include, for example, at least one monocell, bicell, or 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 anode layers and one or more cathode layers are stacked with a solid electrolyte layer interposed therebetween. The monocell may have a structure in which, for example, an anode layer, a solid electrolyte layer, and a cathode layer are stacked sequentially. 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 anode layers and one or more cathode layers are stacked with a solid electrolyte layer interposed therebetween. The bicell may have a structure in which, for example, a cathode layer, a solid electrolyte layer, an anode layer, a solid electrolyte layer, and a cathode layer are stacked sequentially, or a structure in which an anode layer, a solid electrolyte layer, a cathode layer, a solid electrolyte layer, and an anode layer are stacked sequentially. 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 an anode layer and a cathode layer is repeated three or more times. Additionally, the electrode assembly of this specification may have a structure such as a wound type, a stacked type, a stack and folding type, or a lamination / stacked type, but is not limited thereto.

[0060] The above anode layer may include, for example, an anode composite layer and / or an anode current collector layer.

[0061] 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.

[0062] 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.

[0063] The above lithium transition metal oxide is, for example, Li a A 1-b B b D2 (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 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 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 NiGb 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.

[0064] When the above-mentioned cathode active material is a ternary lithium transition metal oxide such as NCA or NCM and contains nickel (Ni), 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.

[0065] The shape of the above-mentioned positive electrode active material may be a particle shape, for example, a sphere, an 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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 aluminum or stainless steel surface treated with carbon, nickel, titanium, silver, etc. In some cases, the positive current collector layer may be omitted.

[0071] 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.

[0072] 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 PS6-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.

[0073] 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.

[0074] 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.

[0075] The elastic modulus of the above sulfide-based solid electrolyte may be, for example, 15 to 35 GPa.

[0076] 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.

[0077] 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.

[0078] Non-limiting examples of the above polymer resins 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, the above polymer electrolyte may be a branched copolymer, comb-like polymer, and cross-linked polymer resin, etc., in which an amorphous polymer such as PMMA, polycarbonate, polysiloxane (PDMS), and / or phosphazene is copolymerized as a comonomer to a polyethylene oxide (PEO) main chain, and may include one or more of these.

[0079] 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.

[0080] 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.

[0081] The cathode layer of the present invention may include, for example, a cathode composite layer and / or a cathode current collector layer.

[0082] The above cathode composite layer may be, for example, a cathode active material layer or a non-cathode coating layer.

[0083] 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.

[0084] 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.

[0085] Examples of the above conductive materials include nickel powder, cobalt oxide, titanium oxide, carbon, etc. As for carbon, any one or more selected from the group consisting of Ketjen black, acetylene black, furnace black, graphite, carbon fiber, and fullerene may be cited.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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).

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] The thickness of the metal layer containing the lithium or lithium alloy may be, for example, within the 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.

[0097] 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.

[0098] 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.

[0099] The above 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 with a surface treated with carbon, nickel, titanium, silver, etc. In some cases, the above negative current collector may be omitted.

[0100] 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.

[0101] The above buffer layer may include, for example, an elastic material.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] The above-described all-solid-state secondary battery may further include, for example, a frame. The frame may be introduced to surround, for example, the side of the anode layer in a '□' shape. When the frame is introduced to surround the side of the anode layer, the frame 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 refer, for example, to the outermost portion in contact with the side of the solid electrolyte layer. The frame 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 frame may fill the space extending from one side of the anode layer to the end portion of the solid electrolyte layer. In some cases, the frame may be introduced to surround the side of the all-solid-state unit cell in a '□' shape. In other examples, the frame may be introduced to surround the side of the all-solid-state unit cell in a '□' shape. However, the frame may not be formed, for example, in the portion where the current collector layer protrudes.

[0106] The above frame may be characterized as, for example, a flame-retardant inert member comprising a matrix and a filler; or an insulating layer comprising a polymer, or a composite of a polymer and an inorganic material, but is not limited thereto, and known materials that can prevent cracks in the layers constituting the unit cell and / or all-solid-state secondary battery, etc., which may occur during the pressurization process, while not hindering the purpose of the present invention may be combined and used in appropriate amounts.

[0107] The above frame may be a flame-retardant inert member comprising, for example, a matrix and a filler. The matrix may comprise, for example, a substrate and a reinforcing material. The substrate may comprise, for example, a first fibrous material. The first fibrous material may comprise, for example, an insulating material, one or more selected from pulp fibers, insulating polymer fibers, and ion-conducting polymer fibers. The reinforcing material may comprise, for example, a second fibrous material. The second fibrous material may be, for example, a flame-retardant material, such as glass fibers, metal oxide fibers, ceramic fibers, etc. The filler may be disposed, for example, inside the matrix, on the surface of the matrix, or both inside and on the surface. The filler may be, for example, an inorganic material. The filler may be, for example, a moisture getter. The above filler can effectively suppress ignition of the all-solid-state secondary battery by releasing adsorbed moisture when the temperature of the all-solid-state secondary battery increases excessively due to thermal runaway caused by the charging and discharging process of the all-solid-state secondary battery or external impact. That is, the filler may be, for example, a flame retardant. The above filler may be, for example, a metal hydroxide having moisture adsorption properties, such as Mg(OH)2, Fe(OH)3, Sb(OH)3, Sn(OH)4, TI(OH)3, Zr(OH)4, Al(OH)3, or a combination thereof. The above flame-retardant inert member may further include, for example, a binder. The above binder may be, for example, a curable polymer that hardens by heat and / or pressure. The above binder may be, for example, a fluorine-based binder such as polyvinylidene fluoride, or an acrylic-based binder such as polyacrylate. The flame-retardant inert member may additionally include other materials in addition to the aforementioned substrate, reinforcing material, filler, and / or binder.The flame-retardant inert member may further include one or more selected from, for example, paper, insulating polymers, ion-conducting polymers, insulating inorganic materials, oxide-based solid electrolytes, and sulfide-based solid electrolytes. The flame-retardant inert member may not include, for example, an electrode active material. The flame-retardant inert member may be a member made of a material other than the electrode active material, which is a material used in the relevant technical field.

[0108] The above frame may be an insulating layer comprising a polymer, or a composite of a polymer and an inorganic material, in other examples. The polymer may include, for example, a fluorinated polymer, a cellulose-based polymer, an epoxy resin, or a combination thereof. Examples of the fluorinated polymer may be a homopolymer of vinylidene fluoride monomers, or a copolymer of vinylidene fluoride monomers and one or more fluorine-containing monomers selected from tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, fluorovinyl, and perfluoroalkyl vinyl ethers. Specifically, the vinylidene monomer may be a vinylidene fluoride homopolymer, a vinylidene fluoride-hexafluoropropylene copolymer, a vinylidene fluoride-chlorotrifluoroethylene copolymer, etc. Examples of the above-mentioned cellulose-based polymers may include one or more selected from cellulose, methyl cellulose, ethyl cellulose, butyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate. There are no restrictions on the form of the above-mentioned cellulose-based polymer, but it may be, for example, in the form of nanofibers. The above-mentioned epoxy resin may be one or more selected from 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, urethane modified epoxy resin, and combinations thereof, but is not limited thereto. The above-mentioned inorganic material may include, for example, metal oxides, metal hydroxides, or combinations thereof. Examples of the above-mentioned 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.

[0109] The above frame may have a single-layer structure or a multi-layer structure, for example. A frame having a multi-layer structure may have a two-layer structure, a three-layer structure, a four-layer structure, or a five-layer structure, for example. Each of the above layers may have a different composition.

[0110] The above frame may be used in various forms, such as, for example, film, tape, sheet, polymer resin, or gasket, but is not limited thereto and may be used in any known form used in the industry.

[0111] The all-solid-state battery of the present invention may include, for example, a case that accommodates the electrode assembly. The case may be a pouch.

[0112] The above pouch-type case can be manufactured by molding a pouch film laminate. In this case, the pouch film laminate may include a substrate layer, a gas barrier layer, and a sealant layer. In the pouch film laminate, the substrate layer, the gas barrier layer, and the sealant layer may be laminated sequentially.

[0113] The above substrate layer is formed, for example, on the outermost layer of a pouch film laminate to protect the secondary battery from friction and collision with the outside, and is made of a polymer to electrically insulate the structure from the outside.

[0114] The above substrate layer may be composed of one or more materials selected from the group consisting of, for example, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber. Preferably, the substrate layer may be composed of polyethylene terephthalate (PET), nylon, or a combination thereof having wear resistance and heat resistance.

[0115] The above substrate layer may have a single-film structure composed of, for example, any one material. In another example, the above substrate layer may have a composite-film structure formed by two or more materials forming separate layers.

[0116] The thickness of the substrate layer may be, for example, 5 μm to 50 μm, specifically 7 μm to 40 μm, more specifically 25 μm to 38 μm. When the thickness of the substrate layer satisfies the above range, the external insulation is excellent, and the overall thickness of the pouch is not thick, so the energy density relative to the volume of the secondary battery may be excellent.

[0117] The above gas barrier layer may be laminated between the substrate layer and the sealant layer to secure the mechanical strength of the pouch, block the entry and exit of gases or moisture from outside the secondary battery, and prevent electrolyte leakage from inside the pouch-type case.

[0118] The above gas barrier layer can be formed of, for example, a metal, and specifically, can be formed of an aluminum alloy thin film. When a gas barrier layer is formed using an aluminum alloy thin film, it is possible to secure mechanical strength above a certain level, while also ensuring light weight, complementary electrochemical properties due to the structure, and heat dissipation. The above aluminum alloy thin film may include one or more metal elements other than aluminum (Al), selected from the group consisting of, for example, iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), magnesium (Mg), silicon (Si), and zinc (Zn).

[0119] The thickness of the gas barrier layer may be, for example, 40 μm to 100 μm, specifically 50 μm to 90 μm, more specifically 55 μm to 85 μm. When the thickness of the gas barrier layer satisfies the above range, the moldability and gas barrier performance may be excellent during cup molding.

[0120] The above sealant layer may be intended to completely seal the interior of a pouch-type case by mutually thermally bonding at the sealing portion when, for example, a pouch-type case accommodating a structure on the inside is sealed. To this end, the sealant layer may be formed of a material having excellent thermal bonding strength.

[0121] The sealant layer may be formed from a material having insulating, corrosion-resistant, and sealing properties. Since the sealant layer must completely seal the inside of the pouch-type case to block material transfer between the inside and the outside, it may be formed from a material having high sealing properties (e.g., excellent thermal bonding strength). The sealant layer may be formed from a polymer material, for example. For example, the sealant layer may include polypropylene, but is not limited thereto.

[0122] The sealant layer may be composed of one or more materials selected from the group consisting of, for example, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber, and preferably may be composed of a polyolefin resin such as polypropylene (PP) and / or polyethylene (PE). In this case, the polypropylene may be composed of cast polypropylene (CPP), acid-modified polypropylene (PPA), polypropylene-ethylene copolymer, and / or polypropylene-butylene-ethylene terpolymer.

[0123] The thickness of the sealant layer may be, for example, 30 μm to 130 μm, specifically 50 μm to 120 μm, and more specifically 70 μm to 100 μm. When the thickness of the sealant layer satisfies the above range, it has the effect of ensuring the sealing strength of the sealing portion while also ensuring the moldability of the pouch film laminate.

[0124] The pouch film laminate can be drawn and stretched by means of a punch or the like for the manufacture of a pouch-type case. As a result, the pouch-type case may include a cup portion and a receiving portion. The receiving portion is a place for housing a structure and may refer to a receiving space formed in the shape of a pocket inside the cup portion as the cup portion is formed.

[0125] The above pouch-type case can be sealed while housing a structure such that, for example, a part of the electrode lead, i.e., the terminal portion, is exposed. For example, the electrode lead can be connected to the electrode tab or the electrode-free portion of the structure.

[0126] The thickness of the above-described all-solid-state battery may be, for example, about 0.1 to 1 mm. In this specification, the thickness of the all-solid-state battery may refer to the thickness after isotropic pressurization.

[0127] In the present invention, for example, the ratio of the thickness of the pad to the thickness of the all-solid-state battery may be 0.5 to 10. In another example, the ratio of the thickness of the pad to the thickness of the all-solid-state battery may be 1.0 or more, 1.5 or more, 2.0 or more, or 2.5 or more, or 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, or 3 or less. By controlling the ratio of the thickness of the pad to the thickness of the all-solid-state battery as described above, sufficient pressure can be applied while maintaining the shape of the all-solid-state battery well during pressurization, thereby providing an all-solid-state battery having excellent energy density without an internal short circuit.

[0128] As the above-mentioned pressure jig, any pressure jig widely known in the art may be used without limitation. The pressure jig may include, for example, first and second plates; and n bolt fastening parts (where n is an integer of 2 or more) including bolts and nuts that fasten the first and second plates to press the all-solid-state battery while the all-solid-state battery is interposed between the first and second plates. In this specification, bolt fastening parts refer to bolts and nuts, and in the present invention, n may be included. Here, n may be an integer of 2 or more, and in other examples may be 3 to 12, 4 to 10, or 6 to 8, but is not limited thereto. The pressure jig may further include, for example, a rotating member formed on the opposite side of the surface of the first plate facing the second plate; and a driving unit that transmits the rotational force of the rotating member to each of the n bolt fastening parts. Accordingly, the above-described pressure jig can perform bolt fastening with uniform pressure on n bolt fastening parts regardless of the fastening position of the bolt fastening parts when fixing or pressurizing an all-solid-state battery between the first and second plates, by having the driving part receive the rotational force of the rotating member and transmit it to the n bolt fastening parts. In this specification, the bolt fastening parts may refer to bolts and nuts, and n may be 2 to 12, 4 to 10, or 6 to 8, but is not limited thereto. The above-described rotating member may rotate clockwise or counterclockwise to fasten or unfasten the bolts and nuts to each other.

[0129] The all-solid-state battery structure of the present invention may, for example, have a discharge capacity of about 155 mAh / g or more after 250 charge-discharge cycles. The discharge capacity may be measured in the manner according to the evaluation example described below. In another example, the all-solid-state battery structure of the present invention may have a discharge capacity of about 157 mAh / g or more, 159 mAh / g or more, 161 mAh / g or more, about 162 mAh / g or more, about 163 mAh / g or more, about 164 mAh / g or more, or about 165 mAh / g or more, or about 180 mAh / g or less, about 175 mAh / g or less, or about 170 mAh / g or less after 250 charge-discharge cycles. The all-solid-state battery structure of the present invention may, for example, have a discharge capacity of about 165 mAh / g or more after 200 charge-discharge cycles. In another example, the all-solid-state battery structure of the present invention may have a discharge capacity of about 166 mAh / g or more, about 167 mAh / g or more, about 168 mAh / g or more, about 169 mAh / g or more, or about 170 mAh / g or more, or about 180 mAh / g or less, or about 175 mAh / g or less after 200 charge-discharge cycles. For example, the all-solid-state battery structure of the present invention may have a discharge capacity of about 170 mAh / g or more after 150 charge-discharge cycles. In another example, the all-solid-state battery structure of the present invention may have a discharge capacity of about 171 mAh / g or more, about 172 mAh / g or more, about 173 mAh / g or more, about 174 mAh / g or more, or about 175 mAh / g or more after 150 charge-discharge cycles, or about 180 mAh / g or less, or about 175 mAh / g or less.

[0130] A second aspect of the present invention relates to a method for manufacturing an all-solid-state battery structure. The details of the first aspect of the present invention may be applied in the same way to the details of the second aspect unless specifically described otherwise.

[0131] The method for manufacturing an all-solid-state battery structure of the present invention may include, for example, the step of introducing an all-solid-state battery and a pad between the first and second plates of a pressure jig (step S1); and / or the step of arranging the pad so that it is located between the first plate and the all-solid-state battery and between the second plate and the all-solid-state battery (step S2), wherein the pad may sequentially include a first pad and a second pad, the second pad may be positioned closer to the all-solid-state battery than the first pad, and the ratio of the Shore A hardness of the second pad to the Shore A hardness of the first pad may be 1.8 to 5.

[0132] The above S1 step may be performed, for example, before, after, or simultaneously with the S2 step. Each of the S1 and S2 steps may be characterized by, for example, positioning the pad and the all-solid-state battery, respectively, at the center of the pressure jig. That is, the center of the pad and the center of the all-solid-state battery, respectively, may be positioned so that they overlap within an error range with a virtual straight line drawn in the stacking direction from the center of the pressure jig.

[0133] The method for manufacturing an all-solid-state battery structure of the present invention may, for example, introduce an all-solid-state battery with a pad provided on at least one of the inner sides of the first and second plates. In another example, the method for manufacturing an all-solid-state battery structure of the present invention may introduce an all-solid-state battery between the first and second plates with a pad provided on at least one of the two sides of the all-solid-state battery.

[0134] The method for manufacturing an all-solid-state battery structure of the present invention may further include, for example, a step (step S3) of pressurizing the all-solid-state battery with the pressurizing jig. By performing the step S3 with the pad introduced as described above, the method for manufacturing an all-solid-state battery structure of the present invention can uniformly pressurize without damaging the all-solid-state battery while lowering the interfacial resistance between the positive electrode layer, the solid electrolyte layer, and the negative electrode layer, thereby providing an all-solid-state battery structure with excellent discharge capacity characteristics, as well as high-rate discharge efficiency and cycle performance. The pressurizing step may be performed at a pressure of, for example, 1 to 50 MPa. The pressure of the pressurizing step may be controlled, for example, by controlling the degree of fastening of the bolt fastening part described above, the rotational speed and / or time of the rotating member, but is not limited thereto, and known methods may be used without limitation as long as they do not impede the purpose of the present invention.

[0135] In addition, even if not specifically described in this specification, methods for manufacturing all-solid-state batteries and / or all-solid-state battery structures widely known in the art may be applied without limitation, provided that they do not impede the purpose of the present invention.

[0136] 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.

[0137] Example 1.

[0138] Manufacturing of all-solid-state batteries

[0139] (Cathode layer)

[0140] 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 SUS foil with a thickness of 10 μm 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.

[0141] (Bipolar layer)

[0142] 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.

[0143] (Solid electrolyte layer)

[0144] The solid electrolyte layer used contained Li6PS5Cl solid electrolyte.

[0145] (Solid-state battery)

[0146] A negative electrode layer, a solid electrolyte layer, and a positive electrode layer were sequentially stacked and sealed in a pouch under vacuum conditions, and then subjected to isotropic pressure treatment at 500 MPa at 85°C for 30 minutes to manufacture an all-solid-state battery (3). At this time, a portion of the positive electrode current collector and the negative electrode current collector were protruded outside the sealed pouch and used as positive electrode terminals and negative electrode terminals.

[0147] Manufacturing of all-solid-state battery structures

[0148] The above-mentioned all-solid-state battery (3) is placed between the first plate (4) and the second plate (5) of the pressure jig (6), and a pad is introduced by sequentially stacking the first pad (1) and the second pad (2) between the first plate (4) and the all-solid-state battery (3) and between the second plate (5) and the all-solid-state battery (3), respectively. At this time, Pad A is used as the first pad (1) and Pad C is used as the second pad (2), and the second pad (2) is placed close to the all-solid-state battery (3) (see FIG. 2).

[0149] Comparative Example 1.

[0150] A solid-state battery structure was manufactured in the same manner as in Example 1, except that pad B was used as the first pad (1) and pad D was used as the second pad (2).

[0151] Classification Pad A Pad B Pad C Pad D Material Silicone Pad Silicone Pad PTFE Pad PTFE Pad Hardness 40 Shore A 70 Shore A 61 Shore D 61 Shore D Thickness 0.3 mm 0.3 mm 1.0 mm 0.5 mm

[0152] Evaluation Example 1. Evaluation of Compressive Force and Deformation

[0153] Compression Force Deflection (CFD) was evaluated for Pad A and Pad B according to ASTM D3574 test C, and the results are shown in Table 2 and Figure 3 below. Specifically, the pads were mounted on a Universal Testing Machine (UTM) from Zwick, and after applying a pre-stress, the new thickness was measured by compressing at a stress of 140 Pa at a speed of 0.6 mm / min. Subsequently, the pads were compressed to 10% of this new thickness and held for 60 seconds, after which the stress was measured. Stress was then measured in the same manner for each of the 20%, 30%, 40%, and 50% compressions.

[0154] Measurement Target CFD 10%(MPa) CFD 20%(MPa) CFD 30%(MPa) CFD 40%(MPa) CFD 50%(MPa) Pad A 0.9 0 1.4 3 2.1 9 3.4 5 5.8 9 Pad B 1.5 1 2.5 0 3.8 3 6.0 6 10.4 3

[0155] Evaluation Example 2. Evaluation of Discharge Capacity and Cycle Performance

[0156] Examples and comparative examples were operated under the following charge-discharge conditions at an operating voltage range of 4.25V-3.0V, a driving temperature of 60℃, and a driving pressure of 10 MPa to evaluate the discharge capacity during a single charge-discharge cycle and the discharge capacity according to the cycle, and the results are shown in FIGS. 4 and FIGS. 5, respectively.

[0157] Charging conditions: 0.33C, 4.25V CC / CV, 0.05C cut-off

[0158] Discharge conditions: 0.33C, 3.0V, CC

[0159] Evaluation Example 3. Evaluation of High-Rate Discharge Efficiency

[0160] The high-rate discharge efficiency was evaluated by driving the examples and comparative examples under the following charge-discharge conditions at an operating voltage range of 4.25V-3.0V, a driving temperature of 60℃, and a driving pressure of 10 MPa, and the results are shown in Fig. 6.

[0161] Charging conditions: 0.1C, 4.25V CC / CV, 0.05C cut-off

[0162] Discharge conditions: 0.1C, 0.1C, 0.33C, 0.5C, 1.0C, 0.1C, 3.0V, CC

[0163]

[0164] [Explanation of the symbol]

[0165] 1: First pad

[0166] 2: Second Pad

[0167] 3: All-solid-state battery

[0168] 4: First plate

[0169] 5: Second plate

[0170] 6: Pressure jig

[0171] 7: Battery structure

Claims

1. A pressure jig comprising first and second plates arranged to face each other; A solid-state battery interposed between the first and second plates; and A pad located at least one of the following: between the first plate and the all-solid-state battery and between the second plate and the all-solid-state battery; Includes, The above pad sequentially includes a first pad and a second pad, wherein the second pad is positioned closer to the all-solid-state battery than the first pad, and An all-solid-state battery structure in which the ratio of the Shore A hardness of the second pad to the Shore A hardness of the first pad is 1.8 to 5.

2. In Paragraph 1, A solid-state battery structure having a thickness ratio of the second pad to the first pad of the above-mentioned first pad of 2 or more.

3. In Paragraph 1, All-solid-state battery structure having a thickness of 0.05 mm to 2 mm of the first pad.

4. In Paragraph 1, All-solid-state battery structure having a thickness of 0.6 mm to 5 mm of the second pad.

5. In Paragraph 1, All-solid-state battery structure having a Shore A hardness of 30 to 50 of the first pad.

6. In Paragraph 1, All-solid-state battery structure having a Shore D hardness of 50 to 70 of the second pad.

7. In Paragraph 1, The above-mentioned first pad is an all-solid-state battery structure having a stress of 8.0 MPa or less measured during a 50% compression force deflection test.

8. In Paragraph 1, A solid-state battery structure comprising one or more selected from the group consisting of thermoplastic elastomer (TPE), TPV (thermoplastic unsaturated rubber), silicone, polyurethane (PU), ethylene propylene diene monomer (EPDM), chloroprene rubber (CR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR), fluorinated rubber (FKM), and combinations thereof.

9. In Paragraph 1, An all-solid-state battery structure comprising one or more selected from the group consisting of polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP), ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polyether ether ketone (PEEK), and combinations thereof.

10. In Paragraph 1, A solid-state battery structure having pads located between the first plate and the solid-state battery and between the second plate and the solid-state battery, respectively.

11. In Paragraph 1, A solid-state battery structure in which the pressure applied to the solid-state battery by the above-mentioned pressure jig is 1 to 50 MPa.

12. In Paragraph 1, The above-described all-solid-state battery includes an electrode assembly and a case housing the electrode assembly, and The above electrode assembly is an all-solid-state battery structure comprising at least one monocell, bicell, or multistack cell.

13. In Paragraph 12, The above case is a pouch, an all-solid-state battery structure.

14. In Paragraph 1, A solid-state battery structure in which the above pad and solid-state battery are each positioned at the center of a pressure jig.

15. A step of introducing the all-solid-state battery and the pad between the first and second plates of the pressure jig; and The method includes the step of arranging pads to be located at least one of the positions between the first plate and the all-solid-state battery and between the second plate and the all-solid-state battery, and The above pad sequentially includes a first pad and a second pad, wherein the second pad is positioned closer to the all-solid-state battery than the first pad, and A method for manufacturing an all-solid-state battery structure in which the ratio of the Shore A hardness of the second pad to the Shore A hardness of the first pad is 1.8 to 5.

16. In Paragraph 15, A method for manufacturing an all-solid-state battery structure, wherein an all-solid-state battery is introduced while having a pad provided on at least one of the inner sides of the first and second plates.

17. In Paragraph 15, A method for manufacturing an all-solid-state battery structure, wherein a pad is provided on at least one of the two sides of the all-solid-state battery, and the all-solid-state battery is introduced between a first plate and a second plate.

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