All-solid-state battery and method for producing same

Abstract

The present invention relates to an all-solid-state battery, more specifically to an all-solid-state battery comprising: a positive electrode layer; a negative electrode layer; a solid electrolyte layer disposed between the positive and negative electrode layers, and comprising a first solid electrolyte layer adjacent to the former and a second solid electrolyte layer adjacent to the latter; and an inert member on the second solid electrolyte layer, the inert member surrounding the sides of the positive electrode layer and first solid electrolyte layer.

Description

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

[0001] The present invention relates to an all-solid-state battery.

[0002]

[0003] Recent industrial demands have led to the active development of batteries with high energy density and safety. For example, lithium-ion batteries are being used not only in information and communication devices, but also in the automotive sector. Safety is particularly important in the automotive sector, as it is directly related to life.

[0004] Recently, all-solid-state batteries have been proposed, replacing the electrolyte in lithium-ion batteries with a solid electrolyte. By eliminating the use of flammable organic dispersion media, all-solid-state batteries significantly reduce the risk of fire or explosion in the event of a short circuit. Therefore, these all-solid-state batteries can offer superior safety.

[0005]

[0006] The problem to be solved by the present invention is to provide an all-solid-state battery.

[0007] Another problem that the present invention seeks to solve is to provide a method for manufacturing an all-solid-state battery.

[0008]

[0009] According to the concept of the present invention, an all-solid-state battery may include: a cathode layer; a solid electrolyte layer disposed between the cathode layer and the anode layer and including a first solid electrolyte layer adjacent to the cathode layer and a second solid electrolyte layer adjacent to the cathode layer; and an inert member on the second solid electrolyte layer.

[0010] The above inert member may surround a side surface of the positive electrode layer and a side surface of the first solid electrolyte layer.

[0011] According to another concept of the present invention, an all-solid-state battery may include a first monocell; a second monocell on the first monocell; and an inert member.

[0012] The second monocell can be arranged symmetrically vertically with respect to the first monocell.

[0013] Each of the first and second monocells may include a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer.

[0014] The positive electrode layer of the first monocell and the positive electrode layer of the second monocell may face each other.

[0015] The solid electrolyte layer of each of the first and second monocells may include a first solid electrolyte layer adjacent to the positive electrode layer and a second solid electrolyte layer adjacent to the negative electrode layer.

[0016] The above inert member may be disposed between the second solid electrolyte layer of the first monocell and the second solid electrolyte layer of the second monocell.

[0017] The inert member may surround a side of the positive electrode layer of each of the first and second monocells and a side of the first solid electrolyte layer of each of the first and second monocells.

[0018] According to another concept of the present invention, a method for manufacturing an all-solid-state battery comprises: laminating a first solid electrolyte layer on a cathode layer and then applying a first pressure to form a cathode laminate;

[0019] Laminating a second solid electrolyte layer on a cathode layer and then applying a second pressure to form a cathode laminate;

[0020] Combining the positive electrode laminate and the negative electrode laminate so that the first solid electrolyte layer and the second solid electrolyte layer are in contact with each other; and

[0021] It may include forming an inert member surrounding the side surface of the positive electrode layer and the side surface of the first solid electrolyte layer on the second solid electrolyte layer.

[0022] The first pressure may be greater than the second pressure.

[0023]

[0024] According to embodiments of the present invention, it is possible to provide an all-solid-state battery that is short-circuit-proof and has excellent cycle characteristics.

[0025]

[0026] Figure 1 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0027] Figure 2 is a plan view of an all-solid-state battery according to one embodiment of the present invention.

[0028] Figure 3 is a cross-sectional view of an all-solid-state battery according to another embodiment of the present invention.

[0029] Figure 4 is a cross-sectional view of an all-solid-state battery according to another embodiment of the present invention.

[0030] Figure 5 is a cross-sectional view of an all-solid-state battery according to another embodiment of the present invention.

[0031] Figure 6 is a conceptual diagram illustrating a method for manufacturing an all-solid-state battery according to one embodiment of the present invention.

[0032] Figure 7 is a conceptual diagram illustrating a method for manufacturing an all-solid-state battery according to one embodiment of the present invention.

[0033]

[0034] To fully understand the structure and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and subject to various modifications. However, the description of these embodiments is provided solely to ensure a complete disclosure of the present invention and to fully inform those skilled in the art of the invention of the scope of the invention.

[0035] In this specification, when a component is referred to as being on another component, it means that it can be formed directly on the other component, or a third component may be interposed between them. Furthermore, in the drawings, the thicknesses of the components are exaggerated for the sake of clarity. Parts designated by the same reference numerals throughout the specification represent the same components.

[0036] Embodiments described herein will be described with reference to cross-sectional and / or plan views, which are ideal illustrations of the present invention. In the drawings, the thicknesses of films and regions are exaggerated for the purpose of effectively explaining the technical contents. Accordingly, the regions illustrated in the drawings have a schematic nature, and the shapes of the regions illustrated in the drawings are intended to illustrate specific shapes of regions of the device and are not intended to limit the scope of the invention. Although terms such as first, second, and third are used to describe various components in various embodiments of the present specification, these components should not be limited by such terms. These terms are used only to distinguish one component from another. The embodiments described and illustrated herein also include complementary embodiments thereof.

[0037] The terminology used herein is for the purpose of describing embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise. As used herein, the words "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components.

[0038]

[0039] Fig. 1 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention. Fig. 2 is a plan view of an all-solid-state battery according to one embodiment of the present invention.

[0040] Referring to FIG. 1, an all-solid-state battery (10) according to one embodiment may include a positive electrode layer (100), a negative electrode layer (200) facing the positive electrode layer (100), a solid electrolyte layer (300) disposed between the positive electrode layer (100) and the negative electrode layer (200), and an inert member (INM). However, the present invention is not limited thereto, and the all-solid-state battery (10) may further include an additional functional layer, such as an adhesion enhancing layer, disposed between the positive electrode layer (100) and the solid electrolyte layer (300) or between the negative electrode layer (200) and the solid electrolyte layer (300).

[0041] The positive electrode layer (100) of one embodiment may include a positive electrode current collector (110) and a positive electrode active material layer (120) disposed on the positive electrode current collector (110). Although not shown, the positive electrode active material layer (120) may include a positive electrode active material, a solid electrolyte, a conductive material, and a binder.

[0042] The positive electrode current collector (110) can provide a reference surface on which the positive electrode active material layer (120) is arranged. The positive electrode current collector (110) can include a plate or foil including, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof.

[0043] Meanwhile, unlike that illustrated in FIG. 1, in one embodiment of the present invention, the positive electrode current collector (110) may be omitted. Although not illustrated, a carbon layer having a thickness of 0.1 μm to 4 μm may be additionally disposed between the positive electrode current collector (110) and the positive electrode active material layer (120) to increase the bonding strength between the positive electrode current collector (110) and the positive electrode active material layer (120).

[0044] The cathode active material may include a material that can reversibly absorb and desorb lithium ions. The cathode active material may include a plurality of particles. The cathode active material may include, but is not necessarily limited to, lithium transition metal oxides such as lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganate, and lithium iron phosphate, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide. The cathode active materials may be used alone or as a mixture of two or more.

[0045] Lithium transition metal oxides include, for example, Li a A 1-b B b D2(0.90≤a≤1, 0≤b≤0.5), Li a E 1-b B b O 2-c D c (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05), LiE 2-b B b O 4-c D c (0≤b≤0.5, 0≤c≤0.05), Li a Ni 1-b-c Co b B c D α (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 O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Mn bB c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2), Li a Nor 1-b-c Mn b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Nor b E c G d O2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1), Li a Nor b Co c Mn d GeO2(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(0.9≤a≤1, 0.001≤b≤0.1), Li a CoG b O2(0.90≤a≤1, 0.001≤b≤0.1), Li a MnG b O2(0.90≤a≤1, 0.001≤b≤0.1), Li a Mn2GbO4(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-fA compound represented by any one of Fe2(PO4)3(0≤f≤2), LiFePO4. In these compounds, the capital letter “A” is Ni, Co, Mn, or a combination thereof, the capital letter “B” is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof, the capital letter “D” is O, F, S, P, or a combination thereof, the capital letter “E” is Co, Mn, or a combination thereof, the capital letter “F” is F, S, P, or a combination thereof, the capital letter “G” is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof, the capital letter “Q” is Ti, Mo, Mn, or a combination thereof, the capital letter “I” is Cr, V, Fe, Sc, Y, or a combination thereof, and the capital letter “J” is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0046] The cathode active material may include, for example, a lithium salt of a transition metal oxide having a layered rock salt type structure among the lithium transition metal oxides described above. The "layered rock salt type structure" is, for example, a cubic rock salt type structure. <111> It is a structure in which oxygen atomic layers and metal atomic layers are alternately and regularly arranged in a direction, and thereby each atomic layer forms a two-dimensional plane. The "cubic rock salt structure" refers to the sodium chloride type (NaCl type) structure, which is a type of crystal structure, and specifically refers to a structure in which the face-centered cubic lattice (fcc) formed by each cation and anion is arranged with a displacement of half of the ridge of the unit lattice. Lithium transition metal oxides having this layered rock salt structure include, for example, LiNi x Co y Al z O2(NCA) or LiNi x Co y Mn zO2(NCM) (0 <x<1,0<y<1, 0<z<1, x+y+z=1) 등의 삼원계 리튬전이금속산화물일 수 있다. 양극 활물질이 층상암염형 구조를 갖는 삼원계 리튬전이금속산화물을 포함하는 경우, 전고체 전지(10)의 에너지 밀도가 커지고 열안정성이 향상될 수 있다.

[0047] The above-described compound included in the positive electrode active material may be covered by a coating layer (not shown). The positive electrode active material may also be a mixture of the above-described compound and a compound to which a coating layer is added. Meanwhile, the coating layer added to the surface of the positive electrode active material may include, for example, an oxide, a hydroxide, an oxyhydroxide, an oxycarbonate, or a hydroxycarbonate of the coating elements below. The compound forming the coating layer is amorphous or crystalline. The coating elements included in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The coating layer may include, for example, Li2O-ZrO2 (LZO). The method for forming the coating layer is selected within a range that does not adversely affect the physical properties of the positive electrode active material. The method for forming the coating layer includes, for example, spray coating, dipping, etc.

[0048] When the positive electrode active material includes nickel (Ni) as a ternary lithium transition metal oxide such as NCA or NCM, for example, the capacity density of the all-solid-state battery (10) can be increased, thereby reducing metal dissolution of the positive electrode active material in a charged state. As a result, the cycle characteristics of the all-solid-state battery (10) in a charged state are improved. Meanwhile, the "cycle characteristics" are characteristics indicating the degree to which the all-solid-state battery (10) is deteriorated by charge / discharge of the all-solid-state battery (10). An all-solid-state battery (10) with high cycle characteristics may have a small degree of deterioration of the all-solid-state battery (10) due to charge / discharge, and an all-solid-state battery (10) with low cycle characteristics may have a large degree of deterioration of the all-solid-state battery (10) due to charge / discharge.

[0049] The positive electrode active material may have a particle shape such as a sphere or an ellipsoid, for example. The particle size and content of the positive electrode active material are not particularly limited.

[0050] A solid electrolyte may be dispersed between the positive electrode active materials. The solid electrolyte dispersed between the positive electrode active materials may have a particle shape. The solid electrolyte dispersed between the positive electrode active materials may include a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics. Examples of the sulfide-based solid electrolyte include Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m, n are positive numbers, capital letter “Z” represents Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are positive numbers, capital letter “M” is one of P, Si, Ge, B, Al, Ga In), 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 include at least one selected from (0≤x≤2).

[0051] Sulfide-based solid electrolytes include, 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 (0≤x≤2) may be an argyrodite-type compound including at least one selected from. In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I. The density of the argyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state battery is reduced, and the defect of the solid electrolyte membrane being penetrated and short-circuited due to the formation of lithium dendrites can be prevented. The elastic modulus of the solid electrolyte may be, for example, 15 GPa to 35 GPa.

[0052] The solid electrolyte in the positive active material layer (120) may have a smaller median particle size (D50) than the solid electrolyte in the solid electrolyte layer (300) described later. For example, the median particle size (D50) of the solid electrolyte included in the positive active material layer (120) 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 median particle size (D50) of the solid electrolyte included in the solid electrolyte layer (300). Meanwhile, the median particle size (D50) may be a median diameter measured using a laser particle size distribution meter.

[0053] The positive electrode active material layer (120) may include a conductive material. The conductive material may have conductivity without causing a chemical change in the all-solid-state battery (10), thereby increasing the conductivity of the positive electrode active material and the solid electrolyte. The conductive material may include a carbon-based material. The conductive material may include, for example, one or more selected from graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0054] The positive electrode active material layer (120) may further include a binder. The binder may bind the positive electrode active material, the solid electrolyte, and the conductive material within the positive electrode active material layer (120) to each other. The binder may include a material for improving the bonding strength between the positive electrode active material layer (120) and the positive electrode current collector (110). The binder may include, for example, polyvinylidene fluoride, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0055] Based on 100 parts by weight of the total of the positive electrode active material, the solid electrolyte, the conductive material, and the binder, the positive electrode active material layer (120) may include 85 parts by weight or more and 92 parts by weight or less of the positive electrode active material. Based on 100 parts by weight of the total of the positive electrode active material, the solid electrolyte, the conductive material, and the binder, the positive electrode active material layer (120) may include 0.5 parts by weight or more and 1.5 parts by weight or less of the binder.

[0056] Based on 100 parts by weight of the solid electrolyte in the positive electrode active material layer (120), the positive electrode active material layer (120) may include 1 part by weight or more and 50 parts by weight or less of a conductive material. When the conductive material is included in the positive electrode active material layer (120) in an amount of less than 1 part by weight based on 100 parts by weight of the solid electrolyte in the positive electrode active material layer (120), the proportion of the conductive material may decrease, thereby lowering the electrical conductivity of the positive electrode active material layer (120). When the conductive material is included in the positive electrode active material layer (120) in an amount of more than 50 parts by weight based on 100 parts by weight of the solid electrolyte in the positive electrode active material layer (120), the proportion of the conductive material may be excessively high, so that a coating layer covering the surface of the solid electrolyte may not be properly formed.

[0057] The positive electrode active material layer (120) may further include additives such as fillers, coating agents, dispersants, and ion conductive aids in addition to the above-described positive electrode active material, solid electrolyte, conductive agent, and binder.

[0058] The negative electrode layer (200) may include a negative electrode current collector (210) and a negative electrode coating layer (220) on the negative electrode current collector (210). The negative electrode current collector (210) may provide a reference surface on which the negative electrode coating layer (220) is disposed. The negative electrode current collector (210) may include, for example, a material that does not react with lithium, i.e., does not form an alloy or a compound with lithium. For example, the negative electrode current collector (210) may include at least one metal selected from the group consisting of copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni). The thickness of the negative electrode current collector (210) may be 1 μm to 20 μm, more specifically 5 μm to 15 μm, and more specifically 7 μm to 10 μm.

[0059] The negative electrode current collector (210) may be composed of one of the above-described metals, or may include an alloy or coating material of two or more metals. The negative electrode current collector (210) may have, for example, a plate shape or a foil shape. Meanwhile, in one embodiment, the negative electrode current collector (210) may be omitted.

[0060] The negative electrode coating layer (220) can allow lithium metal to grow between it and the negative electrode current collector (210) when the all-solid-state battery (10) is charged. The negative electrode coating layer (220) can act as a protective layer for the lithium metal and simultaneously suppress the precipitation and growth of lithium dendrites.

[0061] The cathode coating layer (220) may include a metal and carbon. For example, the cathode coating layer (220) may include at least one metal 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). The cathode coating layer (220) may include at least one carbon selected from the group consisting of carbon black, acetylene black, furnace black, ketjen black, and graphene. In one embodiment, the cathode coating layer (220) may include a mixture of carbon black and silver (Ag).

[0062] The cathode coating layer (220) may further include additives other than metal and carbon. The cathode coating layer (220) may further include, for example, at least one additive selected from the group consisting of a binder, a filler, a coating agent, a dispersant, and an ion conductive additive.

[0063] The negative electrode coating layer (220) may have a smaller thickness than the positive electrode active material layer (120). The thickness of the negative electrode coating layer (220) may be, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive electrode active material layer (120). The thickness of the negative electrode coating layer (220) may be, for example, 1 um to 20 um, 2 um to 10 um, or 3 um to 7 um. If the thickness of the negative electrode coating layer (220) is too thin, lithium dendrites formed between the negative electrode coating layer (220) and the negative electrode current collector (210) may cause the negative electrode coating layer (220) to collapse, thereby deteriorating the cycle characteristics of the all-solid-state battery (10). If the thickness of the cathode coating layer (220) increases excessively, the energy density of the all-solid-state battery (10) may decrease and the internal resistance of the all-solid-state battery (10) due to the cathode coating layer (220) may increase, thereby deteriorating the cycle characteristics of the all-solid-state battery (10).

[0064] Meanwhile, although not shown, a carbon layer may be further included to improve adhesion between the cathode coating layer (220) and the solid electrolyte layer (300).

[0065] A solid electrolyte layer (300) may be provided between the positive electrode layer (100) and the negative electrode layer (200). The solid electrolyte layer (300) may include a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics. The solid electrolyte in the solid electrolyte layer (300) may be the same as or different from any one of the materials included in the solid electrolyte in the positive electrode active material layer (120) described above.

[0066] The solid electrolyte layer (300) may include a first solid electrolyte layer (310) and a second solid electrolyte layer (320). The first solid electrolyte layer (310) may be adjacent to the positive electrode layer (100), and the second solid electrolyte layer (320) may be adjacent to the negative electrode layer (200).

[0067] The second solid electrolyte layer (320) can be in direct contact with the negative electrode coating layer (220). As a result, the second solid electrolyte layer (320) can suppress lithium dendrites formed between the negative electrode coating layer (220) and the negative electrode current collector (210). The second solid electrolyte layer (320) can effectively suppress negative electrode side reactions. As a result, the cell performance of the all-solid-state battery (10) according to the present invention can be improved.

[0068] The solid electrolyte in the solid electrolyte layer (300) may have a particle shape such as a sphere or ellipsoid.

[0069] The solid electrolyte in the solid electrolyte layer (300) may include a sulfide-based solid electrolyte. The solid electrolyte in the solid electrolyte layer (300) may be amorphous, crystalline, or a mixture thereof. In addition, the solid electrolyte may include, for example, at least sulfur (S), phosphorus (P), and lithium (Li) as constituent elements among the above-described sulfide-based solid electrolyte materials. For example, the solid electrolyte may be a material including Li2S-P2S5. When using a sulfide-based solid electrolyte material including Li2S-P2S5 to form the solid electrolyte, the mixing molar ratio of Li2S and P2S5 is, for example, in the range of Li2S:P2S5=50:50 to 90:10.

[0070] In one embodiment, the solid electrolyte in the solid electrolyte layer (300) is Li 7-a M a PS 6-c X c It may be an argyrodite-type compound containing, where X may be Cl, Br, or a combination thereof. M may be Na, K, Fe, Mg, Ca, Ag, Cu, Zr, Zn, or a combination thereof. Each of a and c may be a real number between 0 and 2.

[0071] The density of the argyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state battery is reduced, and the defect of the solid electrolyte membrane being penetrated and short-circuited due to the formation of lithium dendrites can be prevented. The elastic modulus of the solid electrolyte in the solid electrolyte layer (300) is, for example, 15 GPa to 35 GPa.

[0072] The solid electrolyte layer (300) may further include a binder. The binder included in the solid electrolyte layer (300) may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited thereto. The binder of the solid electrolyte layer (300) may be the same as or different from the binder included in the positive electrode active material layer (120) or the binder included in the negative electrode coating layer (220).

[0073] Referring back to FIG. 1, the first solid electrolyte layer (310) may have a first thickness (t1), and the second solid electrolyte layer (320) may have a second thickness (t2). The solid electrolyte layer (300) may have a third thickness (T). The first thickness (t1) And the second thickness (t2) may have different thicknesses. The second thickness (t2) may be greater than the first thickness (t1).

[0074] The thinner the solid electrolyte layer (300), the higher the energy density, but on the other hand, it is difficult to suppress the formation of lithium dendrites in the negative electrode, which may cause a short circuit.

[0075] Solid electrolytes may create voids at the interface between the electrode and the electrolyte, which may act as interfacial resistance and lead to deterioration of battery performance.

[0076] Interfacial resistance can be reduced by simultaneously pressurizing the electrode and solid electrolyte layer. In one embodiment, since a sulfide-based solid electrolyte possesses both high ionic conductivity and mechanical softness, an all-solid-state battery with improved interfacial resistance can be manufactured through pressurization.

[0077] In one embodiment of the present invention, the positive electrode layer (120) and the negative electrode layer (220) may include a pressurizing process in the manufacturing process. In one embodiment of the present invention, the pressurizing process may be performed by applying different pressures to each of the positive electrode layer (120) and the negative electrode layer (220). In one embodiment of the present invention, the positive electrode layer (120) may be manufactured by applying a relatively high pressure compared to the negative electrode layer (220). For example, applying nano-scale particles to the positive and negative electrode active materials may increase the contact area with the solid electrolyte, thereby improving the interfacial resistance. In one embodiment, the positive electrode active material may include secondary particles in which at least two or more primary particles are aggregated in a polycrystal form for reasons such as improved adhesion to the electrode plate, capacity characteristics, and lifespan characteristics. In this case, the interfacial resistance between the positive electrode layer (120) and the first solid electrolyte layer (310) is observed to be greater than the interfacial resistance between the negative electrode layer (220) and the second solid electrolyte layer (320), so that the positive electrode laminate can be manufactured by applying a relatively high pressure compared to the negative electrode laminate. However, this is not limited thereto, and the positive electrode layer (120) and the negative electrode layer (220) can be manufactured through a pressurizing process that applies different pressures to each for various reasons.

[0078] One embodiment of the present invention can solve a process problem that may occur due to differences in interfacial resistance between the positive electrode layer (120) and the first solid electrolyte layer (310) and the negative electrode layer (220) and the second solid electrolyte layer (320) by dividing the solid electrolyte (300) into a first solid electrolyte layer (310) and a second solid electrolyte layer (320). For example, an all-solid-state battery manufactured according to the all-solid-state battery manufacturing method described below can provide an all-solid-state battery manufactured by applying different pressures to each of the positive electrode laminate and the negative electrode laminate.

[0079] One embodiment of the present invention divides a solid electrolyte layer (300) into a first solid electrolyte layer (310) and a second solid electrolyte layer (320) and adjusts the thickness of each layer differently, thereby increasing energy density while suppressing the formation of lithium dendrites within the negative electrode. This improves stability against short-circuit risk and impact and provides an all-solid-state battery (10) with high energy density.

[0080] The ratio of the second thickness t2 to the first thickness t1 (t2 / t1) may be 1 to 20. Specifically, the ratio of the second thickness t2 to the first thickness t1 (t2 / t1) may be 2 to 15, 4 to 11, or 4.5 to 5.5. When the ratio of the second thickness t2 to the first thickness t1 (t2 / t1) is within the above-mentioned numerical range, the formation of lithium dendrites in the negative electrode can be suppressed while increasing the energy density, thereby improving the stability against short-circuit risk and impact and providing an all-solid-state battery (10) with high energy density.

[0081] The first thickness (t1) may be 30 μm or less. Specifically, the first thickness (t1) may be 25 μm or less, 20 μm or less, 14 μm or less, or 10 μm or less. The first thickness (t1) may be 0.1 μm or more. Specifically, the first thickness (t1) may be 1 μm or more, 2 μm or more, 4 μm or more, or 5 μm or more. When the first thickness (t1) exceeds the above-mentioned numerical range, the energy density of the all-solid-state battery (10) may decrease. When the first thickness (t1) does not reach the above-mentioned numerical range, the first thickness (t1) may not reach the diameter of the active material powder in the positive electrode, making it difficult to form an interface.

[0082] The second thickness (t2) may be 30 μm or more. Specifically, it may be 35 μm or more, 40 μm or more, 45 μm or more, 50 μm or more, 55 μm or more, or 60 μm or more. The second thickness (t2) may be 120 μm or less. Specifically, the second thickness (t2) may be 90 μm or less, or 60 μm or less. When the second thickness (t2) is less than the above-mentioned numerical range, it may be difficult to suppress the formation of lithium dendrites in the negative electrode, which may cause a short circuit. When the second thickness (t2) exceeds the above-mentioned numerical range, the energy density of the all-solid-state battery (10) may decrease.

[0083] The third thickness (T) may be 120 μm or less. Specifically, the third thickness (T) may be 90 μm or less, or 60 μm or less. The third thickness (T) may be 10 μm or more. Specifically, the third thickness (T) may be 30 μm or more, or 50 μm or more. If the third thickness (T) exceeds the above numerical range, the energy density of the all-solid-state battery (10) may decrease.

[0084] Referring to FIGS. 1 and 2, the area of ​​the anode layer (100) and the area of ​​the cathode layer (200) may be different from each other. Specifically, the area of ​​the cathode layer (200) may be larger than the area of ​​the anode layer (100). The anode layer (100) may be completely overlapped within the cathode layer (200).

[0085]

[0086] In one embodiment of the present invention, the first solid electrolyte layer (310) may have substantially the same area as the positive electrode layer (100). The second solid electrolyte layer (320) may have substantially the same area as the negative electrode layer (200).

[0087] Referring to FIGS. 1 and 2, the first solid electrolyte layer (310) may have a first width (W1) in the first direction (D1). The second solid electrolyte layer (320) may have a second width (W2) in the first direction (D1). The first width (W1) may be smaller than the second width (W2).

[0088] The difference between the second width (W2) and the first width (W1) may be 10 mm or less. Specifically, the difference between the second width (W2) and the first width (W1) may be 8 mm or less, 5 mm or less, or 3 mm or less. The difference between the second width (W2) and the first width (W1) may be 0.1 mm or more, 0.5 mm or more, or 1 mm or more. If the numerical range is exceeded, the size of the positive electrode layer (100) becomes relatively small, so the discharge capacity may be lowered, and the energy density of the all-solid-state battery (10) may be reduced. If the numerical range is not reached, it may be difficult to suppress the formation of lithium dendrites in the negative electrode, which may cause a short circuit.

[0089] The ratio (W2 / W1) of the second width (W2) to the first width (W1) may be 1 to 1.6. Specifically, the ratio (W2 / W1) of the second width (W2) to the first width (W1) may be 1 to 1.5, 1 to 1.4, 1 to 1.3, 1 to 1.2, or 1 to 1.1.

[0090] When the ratio (W2 / W1) of the second width (W2) to the first width (W1) exceeds the above numerical range, the energy density of the all-solid-state battery (10) is reduced.

[0091] Referring to FIGS. 1 and 2, the first solid electrolyte layer (310) may have a third width (W3) in the second direction (D2). The second solid electrolyte layer (320) may have a fourth width (W4) in the second direction (D2). The third width (W3) may be smaller than the fourth width (W4).

[0092] The difference between the third width (W3) and the fourth width (W4) may be 10 mm or less. Specifically, the difference between the third width (W3) and the fourth width (W4) may be 8 mm or less, 5 mm or less, or 3 mm or less. The difference between the fourth width (W4) and the third width (W3) may be 0.1 mm or more, 0.5 mm or more, or 1 mm or more. If the numerical range is exceeded, the size of the positive electrode layer (100) becomes relatively small, so the discharge capacity may be lowered and the energy density of the all-solid-state battery (10) may be reduced. If the numerical range is not reached, it may be difficult to suppress the formation of lithium dendrites in the negative electrode, which may cause a short circuit.

[0093] The ratio (W4 / W3) of the fourth width (W4) to the third width (W3) may be 1 to 1.6. Specifically, the ratio (W4 / W3) of the fourth width (W4) to the third width (W3) may be 1 to 1.5, 1 to 1.4, 1 to 1.3, 1 to 1.2, or 1 to 1.1.

[0094] When the ratio (W4 / W3) of the fourth width (W4) to the third width (W3) exceeds the above numerical range, the energy density of the all-solid-state battery (10) is reduced.

[0095] Referring to FIG. 1, an inert member (INM) may be disposed on the second solid electrolyte layer (320). The inert member (INM) may be disposed to surround the side of the positive electrode layer (100) and the side of the first solid electrolyte layer (310). By including the inert member (INM), uniform pressurization is enabled during manufacturing and / or charging / discharging of the all-solid-state battery (10), thereby preventing cracking of the solid electrolyte layer (300) and consequently improving the cycle characteristics of the all-solid-state battery (10).

[0096] Referring to FIG. 1, the thickness t3 of the inert member (INM) may be less than or equal to the sum of the thickness t4 of the positive electrode layer (100) and the thickness t1 of the first solid electrolyte layer (310).

[0097] When the thickness of the above-mentioned inert member (INM) is greater than the sum of the thickness (t1) of the first solid electrolyte layer (310) and the thickness (t4) of the positive electrode layer (100), the positive electrode layer (100) and the first solid electrolyte layer (310) may not be sufficiently pressurized during the manufacture of the all-solid-state battery (10).

[0098] The above-mentioned inert member (INM) may be a flame-retardant inert member. The flame-retardant inert member prevents thermal runaway and ignition of the all-solid-state battery (10) by providing flame retardancy, thereby improving the safety of the all-solid-state battery (10). In addition, the flame-retardant inert member prevents deterioration of the all-solid-state battery (10) by absorbing residual moisture within the all-solid-state battery (10), thereby improving the lifespan characteristics of the all-solid-state battery (10).

[0099] The flame-retardant inert member includes a matrix and a filler. The matrix includes, for example, a substrate and a reinforcing material. The matrix includes, for example, a fibrous substrate and a fibrous reinforcing material. Since the matrix includes the substrate, the matrix can have elasticity. Therefore, the matrix can effectively accommodate volume changes during charging and discharging of the all-solid-state battery (10) and can be arranged at various positions. The substrate included in the matrix includes, for example, a first fibrous material. Since the substrate includes the first fibrous material, the volume changes of the positive electrode layer (100) occurring during the charging and discharging of the all-solid-state battery (10) can be effectively accommodated and deformation of the flame-retardant inert member (INM) due to the volume changes of the positive electrode layer (100) can be effectively suppressed. The first fibrous material is, for example, a material having an aspect ratio of 5 or more, 20 or more, or 50 or more. The first fibrous material is, for example, a material having an aspect ratio of 5 to 1000, 20 to 1000, or 50 to 1000. The first fibrous material is, for example, an insulating material. Since the first fibrous material is an insulating material, a short circuit between the positive electrode layer (100) and the negative electrode layer (200) caused by lithium dendrites, etc., generated during the charge and discharge process of the all-solid-state battery (10) can be effectively prevented. The first fibrous material includes, for example, at least one selected from pulp fibers, insulating polymer fibers, and ion-conductive polymer fibers. The strength of the matrix is ​​improved by the inclusion of a reinforcing material in the matrix. Therefore, the matrix can prevent excessive volume change during charge and discharge of the all-solid-state battery (10) and deformation of the all-solid-state battery (10). The reinforcing material included in the matrix includes, for example, a second fibrous material. Since the reinforcing material includes the second fibrous material, the strength of the matrix can be increased more uniformly. The second fibrous material is, for example, a material having an aspect ratio of 3 or more, 5 or more, or 10 or more.The first fibrous material is, for example, a material having an aspect ratio of 3 to 100, 5 to 100, or 10 to 100. The second fibrous material is, for example, a flame-retardant material. Since the second fibrous material is a flame-retardant material, it can effectively suppress ignition due to thermal runaway that occurs during the charge / discharge process of the all-solid-state battery (10) or due to external impact. The second fibrous material is, for example, a glass fiber, a metal oxide fiber, a ceramic fiber, or the like. The glass fiber is determined according to the composition of the metal oxide constituting the glass. The glass fiber is, for example, a silicate glass fiber. The metal oxide fiber is, for example, a silica (SiO2) fiber, an alumina (Al2O3) fiber, a bohemite fiber, or the like. The ceramic fiber is, for example, a silicon carbide fiber, or the like. The flame-retardant inert member includes a filler in addition to the matrix. The filler may be disposed within the matrix, on the surface of the matrix, or on both the inside and the surface. The filler is, for example, an inorganic material. The filler included in the flame-retardant inert member is, for example, a moisture getter. The filler removes moisture remaining in the all-solid-state battery (10) by adsorbing moisture, for example, at a temperature below 100°C, thereby preventing deterioration of the all-solid-state battery (10). In addition, when the temperature of the all-solid-state battery (10) increases to 150°C or more due to thermal runaway occurring during the charge / discharge process of the all-solid-state battery (10) or an external impact, the filler can release the adsorbed moisture, thereby effectively suppressing ignition of the all-solid-state battery (10). That is, the filler is, for example, a flame retardant. The filler is, for example, a metal hydroxide having moisture adsorption properties. The metal hydroxide contained in the filler is, for example, 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 content of the filler included in the flame-retardant inert member is, for example, 10 to 80 parts by weight, 20 to 80 parts by weight, 30 to 80 parts by weight, 40 to 80 parts by weight, 50 to 80 parts by weight, 60 to 80 parts by weight, or 65 to 80 parts by weight, based on 100 parts by weight of the flame-retardant inert member. The flame-retardant inert member may include, for example, a binder. The binder may include, for example, a curable polymer. The curable polymer is a polymer that is cured by heat and / or pressure. The curable polymer is, for example, a solid at room temperature. The flame-retardant inert member includes, for example, a thermo-pressure curable film and / or a cured product thereof. The thermo-pressure curable polymer is, for example, TSA-66 from Toray. Alternatively, the binder may include a general binder used in the art. The binder may be, for example, a fluorine-based binder such as polyvinylidene fluoride or an acrylic binder such as polyacrylate. The content of the binder included in the flame-retardant inert member is, for example, 1 to 10 parts by weight, 1 to 5 parts by weight, or 1 to 3 parts by weight based on 100 parts by weight of the flame-retardant inert member. The density of the substrate included in the flame-retardant inert member or the density of the reinforcing material may be, for example, 10% to 300%, 10% to 150%, 10% to 140%, 10% to 130%, or 10% to 120% of the density of the positive electrode active material included in the positive electrode active material layer (120). The flame-retardant inert member is a member that does not include an electrochemically active material, for example, an electrode active material. The electrode active material is a material that absorbs / releases lithium. A flame-retardant inert material is a material other than an electrode active material and is made of a material used in the relevant technical field.

[0100] The inert member (INM) may be, for example, a gasket. By using a gasket as the inert member (INM), cracks in the solid electrolyte layer (300) caused by a pressure difference during the pressing process can be effectively suppressed.

[0101] Figure 3 is a cross-sectional view illustrating an all-solid-state battery according to another embodiment of the present invention. In this embodiment, detailed descriptions of technical features that overlap with those previously described with reference to Figures 1 and 2 will be omitted, and differences will be described in detail.

[0102] Referring to FIG. 3, the negative electrode layer (200) of the all-solid-state battery (10) may further include a lithium metal layer (400) between the negative electrode current collector (210) and the negative electrode coating layer (220). The thickness of the lithium metal layer (400) may further increase when the all-solid-state battery (10) is charged. The negative electrode coating layer (220) serves as a protective layer for the lithium metal layer (400), and at the same time, may suppress the growth of lithium dendrites from the lithium metal layer (400).

[0103] The lithium metal layer (400) may be a metal thin film containing lithium or a lithium alloy. The lithium alloy may include, but is not limited to, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, etc., and any lithium alloy may be used. The lithium metal layer (400) may contain one of these alloys or lithium. Alternatively, the lithium metal layer (400) may contain various types of alloys.

[0104] The lithium metal layer (400) may have a fifth width (W5) in the first direction (D1). The fifth width (W5) may be equal to or greater than the first width (W1). The fifth width (W5) may be equal to or less than the second width (W2). For example, the fifth width (W5) may be greater than the first width (W1) and less than the second width (W2).

[0105] Figure 4 is a cross-sectional view illustrating an all-solid-state battery according to another embodiment of the present invention. In this embodiment, detailed descriptions of technical features that overlap with those previously described with reference to Figures 1 to 3 will be omitted, and differences will be described in detail.

[0106] Referring to FIG. 4, a bi-cell all-solid-state battery (20) may include a first mono-cell (510), a second mono-cell (520), and an inert member (INM).

[0107] Each of the first and second monocells (510, 520) may include a positive electrode layer (100, 100'), a negative electrode layer (200, 200'), and a solid electrolyte layer (300, 300') disposed between the positive electrode layer (100, 100') and the negative electrode layer (200, 200'). The solid electrolyte layers (300, 300') of each of the first and second monocells (510, 520) may include a first solid electrolyte layer (310, 310') adjacent to the positive electrode layer (100, 100') and having a first width (W1) and a first thickness (t1), and a second solid electrolyte layer (320, 320') adjacent to the negative electrode layer (200, 200') and having a second width (W2) and a second thickness (t2). The second monocell (520) may be arranged symmetrically vertically with respect to the first monocell (510). The positive electrode layer (100) of the first monocell (510) and the positive electrode layer (100') of the second monocell (520) may face each other.

[0108] Referring to FIG. 4, the inert member (INM) may be disposed between the second solid electrolyte layer (320) of the first mono-cell (510) and the second solid electrolyte layer (320') of the second mono-cell (520). The inert member (INM) may surround the side of the positive electrode layer (100, 100') of each of the first and second mono-cells and the side of the first solid electrolyte layer (310, 310') of each of the first and second mono-cells. By including the inert member (INM), uniform pressurization is enabled during manufacturing and / or charging / discharging of the all-solid-state battery (20), thereby preventing cracking of the solid electrolyte layer (300), and consequently improving the cycle characteristics of the all-solid-state battery (20).

[0109] Referring to FIG. 4, the positive electrode layer (100) of the first monocell (510) and the positive electrode layer (100') of the second monocell (520) may have substantially the same thickness. The first solid electrolyte (310) of the first monocell (510) and the first solid electrolyte (310') of the second monocell (520) may have substantially the same thickness.

[0110] The thickness t3 of the above inert member can satisfy the following equation 1.

[0111] [Formula 1]

[0112] t1+t 4 < t 3 ≤ 2 * ( t1+t 4)

[0113] t1 is the thickness of the first solid electrolyte layer (310), t4 is the thickness of the above anode layer (100).

[0114] If the thickness (t3) of the inert member (INM) is smaller than the sum of the thickness (t1) of the first solid electrolyte layer (310) and the thickness (t4) of the anode layer (100), an appropriate pressure may not be applied to the side of the second solid electrolyte layer (320), and thus cracks may occur in the solid electrolyte layer (300). If the thickness (t3) of the inert member (INM) is larger than the sum (2*(t1+t4)) of the thickness (t1) of the first solid electrolyte layer (310) of the first monocell (510) and the thickness (t4) of the anode layer (100), and the thickness (t1) of the first solid electrolyte layer (310') of the second monocell (520) and the thickness (t4) of the anode layer (100'), the anode layer (100) and the first solid electrolyte layer (310) may not be sufficiently pressurized.

[0115] Although not shown in the drawing, the inert member (INM) may have a multi-layer structure. Specifically, the inert member (INM) may include a first inert member adjacent to the second solid electrolyte layer (320) of the first mono-cell (510) and a second inert member adjacent to the second solid electrolyte layer (320') of the second mono-cell (520). When the inert member (INM) has a multi-layer structure, the inert member (INM) may be laminated on each of the first mono-cell (510) and the second mono-cell (520) and then the bi-cell all-solid-state battery (20) may be manufactured, thereby ensuring processability. In addition, it may be easy to form one or more adhesive layers and support layers between the first inert member and the second inert member. The adhesive layer effectively prevents, for example, a gap between the positive electrode layer (100) and the solid electrolyte layer (300) due to a change in the volume of the positive electrode layer (100) that occurs during the charge / discharge process of an all-solid-state battery, and improves the strength of the inert member by providing a bonding force between the support layer and another layer. The support layer provides support to the inert member, prevents unevenness of the pressure applied to the solid electrolyte layer (300) during the pressurizing process or the charge / discharge process, and prevents deformation of the shape of the all-solid-state battery being manufactured.

[0116] Figure 5 is a cross-sectional view illustrating an all-solid-state battery according to another embodiment of the present invention. In this embodiment, detailed descriptions of technical features that overlap with those previously described with reference to Figures 1 to 4 will be omitted, and differences will be described in detail.

[0117] Referring to FIG. 5, the bi-cell all-solid-state battery (20) may further include an elastic member (ELP) disposed on one surface of the negative electrode layer (200). The elastic member (ELP) may be composed of members capable of absorbing volume changes (expansion) of the all-solid-state battery (20) due to charge and discharge and capable of elastic deformation, and more specifically, may be composed of a material having a lower elastic modulus than the positive electrode current collector and the negative electrode current collector. The material constituting the elastic member (ELP) may have a slope of a stress-displacement curve of 200 MPa or less at a displacement of 80% or less. Specifically, the material constituting the elastic member (ELP) may have a slope of a stress-displacement curve of 50 MPa or less at a displacement of 80% or less, and may have a slope of 10 MPa or less at a displacement of 50% or less.

[0118] The material of the above elastic member (ELP) may include, but is not limited to, epoxy resin, acrylic resin, polyimide resin, polyester resin, polypropylene resin, polyamide resin, polystyrene resin, polyvinyl chloride resin, polycarbonate resin, fluororesin such as PTFE, silicone rubber, etc. Each elastic member (ELP) may be composed of a single material, or may be composed of a combination of multiple materials. In addition, each elastic member (ELP) may include the same material, or may include different materials. In addition, the elastic member (ELP) may include an insulating material, and may insulate between each bi-cell all-solid-state battery (20). The insulating material may have a surface resistance of 1.0*10 17 Ω·cm 2It may be an ideal, and specifically, it may be a fluororesin such as PTFE or silicone rubber.

[0119] Since an elastic member (ELP) is arranged between each of the bi-cell all-solid-state batteries (20), the pressure generated when the all-solid-state batteries (20) are charged and expanded can be distributed, thereby reducing the unevenness of the pressure applied to each all-solid-state battery (20) by charging and discharging. In addition, this can suppress cracking or deformation of the electrolyte layer that may occur as charging and discharging are repeated, and can suppress deterioration of battery characteristics such as cycle characteristics.

[0120] Figure 6 is a conceptual diagram illustrating a method for manufacturing an all-solid-state battery according to one embodiment of the present invention. Figure 7 is a conceptual diagram illustrating a method for manufacturing an all-solid-state battery according to one embodiment of the present invention.

[0121] Referring to FIGS. 6 and 7, an all-solid-state battery (10) according to one embodiment of the present invention can be manufactured by stacking a first solid electrolyte layer (310) on a positive electrode layer (100), then applying a first pressure to form a positive electrode laminate, stacking a negative electrode layer (200) and the second solid electrolyte layer (320), then applying a second pressure to form a negative electrode laminate, then combining the positive electrode laminate and the negative electrode laminate so that the first solid electrolyte layer (310) and the second solid electrolyte layer (320) are in contact with each other, and then forming an inert member (INM) on the second solid electrolyte layer (320) to surround a side surface of the positive electrode layer (100) and a side surface of the first solid electrolyte layer (310).

[0122]

[0123] The present invention manufactures a positive electrode laminate and a negative electrode laminate by applying separate pressurization methods, thereby allowing the first pressure and the second pressure to be controlled differently. This allows a relatively lower pressure to be applied to a laminate that has weak mechanical strength or is structurally unbalanced among the positive electrode laminate and the negative electrode laminate, and thus may be damaged when pressurized at high pressure. The first pressure may be greater than the second pressure.

[0124] The formation of the above-described positive and negative electrode laminates may include a pressing process using a roll press. However, this method is not necessarily limited to this method, and any pressing process applicable in the relevant technical field may be applied. For example, pressing processes such as a hydraulic plate press and a warm isostatic press may be applied.

[0125] When roll press is applied during the formation process of the above-mentioned positive electrode laminate, the linear pressure of the first pressure may be 1 ton / cm to 5 ton / cm. Specifically, the linear pressure of the first pressure may be 1 ton / cm to 4 ton / cm, 1 ton / cm to 3 ton / cm, or 1 ton / cm to 2.5 ton / cm.

[0126] When roll press is applied during the formation process of the above-mentioned negative electrode laminate, the linear pressure of the second pressure may be 1 ton / cm to 4 ton / cm. Specifically, the linear pressure of the first pressure may be 1 ton / cm to 3 ton / cm, 1 ton / cm to 2.5 ton / cm, or 1 ton / cm to 2 ton / cm.

[0127] The above pressurization process can be carried out at a relatively high temperature. Specifically, the pressurization process can be carried out at 60 to 150°C, 80 to 130°C, or 100 to 125°C.

[0128] Forming the above positive electrode laminate and negative electrode laminate may include a preheating process prior to the pressurizing process. Specifically, the positive electrode laminate and negative electrode laminate may be preheated to ±10°C and ±5°C, respectively, of the temperature at which the pressurizing process is performed. The preheating process may prevent damage to the positive electrode laminate and negative electrode laminate due to rapid temperature changes during the high-temperature pressurizing process.

[0129] Referring to FIG. 6, in a method for manufacturing an all-solid-state battery according to another embodiment of the present invention, forming a positive electrode laminate includes laminating a first functional layer (FNL1) on a first solid electrolyte layer before applying the first pressure, forming a negative electrode laminate includes laminating a second functional layer (FNL2) on the second solid electrolyte layer before applying the second pressure, and may further include removing the first functional layer (FNL1) and the second functional layer (FNL2) before combining the positive electrode laminate and the negative electrode laminate. The first functional layer (FNL1) and the second functional layer (FNL2) can prevent damage to the solid electrolyte by preventing the solid electrolyte layer from being directly exposed during a high-temperature pressurization process.

[0130] The first functional layer (FNL1) and the second functional layer (FNL2) may include a plate or foil containing indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof. The first functional layer (FNL1) and the second functional layer (FNL2) may include polyethylene terephthalate (PET), polycarbonate (PC), polyimide (PI), or a mixture thereof.

[0131] Referring to FIG. 7, an all-solid-state battery (10) according to one embodiment of the present invention can be manufactured by forming an inert member (INM) on the second solid electrolyte layer (320) so that the first solid electrolyte layer (310) and the second solid electrolyte layer (320) are in contact with each other, surrounding the side surface of the positive electrode layer (100) and the side surface of the first solid electrolyte layer (310) while combining the positive electrode laminate and the negative electrode laminate, and applying a third pressure.

[0132] The formation of the above-described positive and negative electrode laminates may include a pressurizing process using a hydraulic plate press. However, this method is not necessarily limited to this method, and any pressurizing process applicable in the relevant technical field may be applied. For example, pressurizing processes such as roll press and warm isostatic press may be applied.

[0133] When roll press is applied during the forming process of the above-mentioned all-solid-state battery (10), the linear pressure of the third pressure may be 0.1 ton / cm or more. Specifically, the linear pressure of the third pressure may be 0.5 ton / cm or more, and the linear pressure may be 1.0 ton / cm or more. The linear pressure of the third pressure may be 2.0 ton / cm or less. Specifically, the linear pressure of the third pressure may be 1.5 ton / cm or less, 1.0 ton / cm or less, 0.7 ton / cm or less, and 0.5 ton / cm or less.

[0134]

[0135] Hereinafter, the present invention will be described in more detail through examples. However, these examples are intended to exemplify the present invention and the scope of the present invention is not limited to these examples.

[0136]

[0137] Example 1

[0138] (Cathode layer manufacturing)

[0139] A 10 ㎛ thick SUS foil was prepared as a negative electrode current collector. In addition, carbon black (CB) with a primary particle size of approximately 30 nm and silver (Ag) particles with an average particle size (D50) of approximately 60 nm were prepared as negative electrode active materials. 4 g of a mixed powder of carbon black (CB) and silver (Ag) particles in a weight ratio of 3:1 was placed in a container, and 4 g of an NMP solution containing 7 wt% PVDF binder (Kureha #9300) was added thereto to prepare a mixed solution. Subsequently, NMP was gradually added to the mixed solution while stirring the mixed solution to prepare a slurry. The prepared slurry was applied to a Ni sheet using a bar coater and dried in air at 80 ° C. for 10 minutes. The laminate thus obtained was vacuum dried at 40 ° C. for 10 hours. The dried laminate was cold rolled to flatten the surface of the first negative electrode active material layer of the laminate. The negative electrode layer was manufactured through the above process. The thickness of the first negative electrode active material layer included in the negative electrode layer was approximately 7 μm. The areas of the first negative electrode active material layer and the negative electrode current collector were the same.

[0140]

[0141] (Anode layer manufacturing)

[0142] LiNi coated with Li2O-ZrO2 (LZO) as a cathode active material 0.8 Co 0.15 Mn 0.05O2(NCM) was prepared. The LZO-coated cathode active material was prepared according to the method disclosed in Korean Patent Publication No. 10-2016-0064942. Li6PS5Cl (D50 = 0.5 μm, crystalline) in the form of an argyrodite crystal was prepared as a solid electrolyte. Polytetrafluoroethylene (PTFE) binder was prepared as a binder. Carbon nanofibers (CNF) were prepared as a conductive agent. These materials were mixed with a xylene solvent in a weight ratio of cathode active material: solid electrolyte: conductive agent: binder = 84:11.5:3:1.5, and the slurry was molded into a sheet shape, and then vacuum-dried at 40°C for 8 hours to prepare a cathode sheet. The manufactured positive electrode sheets were each placed on the cross-section of a positive electrode current collector made of aluminum foil coated with carbon on the cross-section, and heated roll press was performed at 85°C to manufacture a positive electrode layer. The total thickness of the positive electrode layer was approximately 120 μm. The thickness of the positive electrode active material layer was approximately 107 μm, and the thickness of the carbon-coated (1 mm thick) aluminum foil was approximately 13 μm. The areas of the positive electrode active material layer and the positive electrode current collector were the same.

[0143]

[0144] (Manufacturing of solid electrolyte layer, dry)

[0145] A mixture was prepared by adding 1 part by weight of a first binder of polytetrafluoroethylene (PTFE) and 1 part by weight of a second binder of polyvinylidene fluoride (PVDF) to 98 parts by weight of the solid electrolyte, which is a Li6PS5Cl sulfide-based solid electrolyte (D50 = 10 μm, crystalline), which is an argyrodite crystal, and mixing them in a grind mixer. The prepared mixture was added to a mortar heated to 80°C and stirred to prepare a dough. The prepared dough was passed through a roller and formed into a sheet to prepare a solid electrolyte membrane of a certain thickness. A solid electrolyte layer was manufactured by the above process. The solid electrolyte layers were prepared as a first solid electrolyte layer having substantially the same area as the positive electrode layer, and a second solid electrolyte layer having substantially the same area as the negative electrode layer, respectively. The elastic modulus of the sulfide-based solid electrolyte was about 15 GPa to 30 GPa.

[0146]

[0147] (Manufacturing of all-solid-state batteries)

[0148] The positive electrode layer and the first solid electrolyte layer were laminated and pressed using a roll press method. A positive electrode laminate was manufactured by applying a linear pressure of 2.5 ton / cm at 120°C. The negative electrode layer and the second solid electrolyte layer were laminated and pressed using a roll press method. A negative electrode laminate was manufactured by applying a linear pressure of 2.0 ton / cm at 120°C. The positive electrode laminate and the negative electrode laminate were combined to manufacture an all-solid-state battery.

[0149] Referring to Fig. 1, the second width (W2) of the second solid electrolyte layer was manufactured to be 4 mm larger than the first width (W1) of the first solid electrolyte layer. The thickness (t1) of the first solid electrolyte layer was 10 μm, and the thickness (t2) of the second solid electrolyte layer was manufactured to be 50 μm.

[0150]

[0151] Example 2

[0152] An all-solid-state battery was manufactured in the same manner as Example 1, except that the thickness (t1) of the first solid electrolyte layer was 5 μm and the thickness (t2) of the second solid electrolyte layer was 55 μm.

[0153]

[0154] Example 3

[0155] An all-solid-state battery was manufactured in the same manner as Example 1, except that the thickness (t1) of the first solid electrolyte layer was 10 μm and the thickness (t2) of the second solid electrolyte layer was 40 μm.

[0156]

[0157] Evaluation Example 1: Impact Safety

[0158] The impact stability level of the all-solid-state batteries manufactured by the Examples and Comparative Examples was confirmed by a sine wave vibration test (Sine test: f=55Hz; force=25gf; duration=1hr, 3-axis). Specifically, 10 samples were manufactured for each Example and Comparative Example, and then a sine wave vibration test was performed. The results of the impact stability test were classified into ⊙ (excellent, 0 to 1 broken cell), ○ (good, 2 to 3 broken cells), △ (fair, 4 to 6 broken cells), and X (poor, 7 to 10 broken cells) based on the number of broken cells among the 10 samples. The classification results are shown in Table 1 below.

[0159]

[0160] Evaluation Example 2: Energy Density

[0161] The energy density (Wh / L) of the all-solid-state batteries manufactured by the examples and comparative examples was measured by the standard calculation method (based on an 80Ah stack cell, capacity*standard voltage / volume). The results of the energy density evaluation experiment are shown in Table 1 below, with ⊙ (excellent) if the energy density is 900 Wh / L or higher, ○ (good) if it is 800 Wh / L to 900 Wh / L, △ (fair) if it is 600 Wh / L to 800 Wh / L, and X (poor) if it is 600 Wh / L or less.

[0162]

[0163] Evaluation Example 3: Initial Capacity

[0164] The all-solid-state batteries manufactured by the Examples and Comparative Examples were evaluated by the following charge-discharge tests. The charge-discharge tests were performed by placing the all-solid-state batteries in a thermostatic chamber at 45°C. The first cycle was performed by charging at a constant current of 0.1C until the battery voltage reached 4.25 V, and then charging was performed at a constant voltage of 4.25 V with a 0.05C cut-off condition when 4.25 V was reached. Subsequently, discharging was performed at a constant current of 0.1C until the battery voltage reached 2.5 V. The discharge capacity of the first cycle was taken as the initial capacity. The results are shown in Table 1 below.

[0165]

[0166] Evaluation Example 4: Life Characteristics Evaluation

[0167] The all-solid-state batteries manufactured by the Examples and Comparative Examples were evaluated by the following charge-discharge tests. The charge-discharge tests were performed by placing the all-solid-state batteries in a thermostatic chamber at 45°C. In the first cycle, the batteries were charged at a constant current of 0.33C until the battery voltage reached 4.25 V, and when 4.25 V was reached, constant voltage charging was performed at 4.25 V with a 0.1C cut-off condition. Subsequently, the batteries were discharged at a constant current of 0.33C until the battery voltage reached 2.5 V. From the second cycle onwards, charging and discharging were performed up to 250 cycles under the same conditions as the first cycle. As the number of cycles at which a short circuit occurs increases, this means that the life characteristics improve. The results of the charge-discharge tests are shown in Table 1 below.

[0168] Inert material t1 (㎛) t2 (㎛) Impact stability Energy density evaluation Initial capacity (mAh / g) Short circuit occurrence time (times) Example 1 Application 1055⊙○190>250 * Example 2 Application 555⊙○190>250 Example 3 Application 1040○⊙185>250

[0169] *">250" means that no short circuit occurs after 250 cycles of testing.

[0170] As shown in Table 1 above, the all-solid-state batteries of Examples 1 to 3, in which an inert member was applied to the side of the positive electrode layer, had differences in impact stability and energy density performance depending on the thickness of t1 and t2, but generally had excellent impact stability and energy density. In particular, the all-solid-state batteries of Examples 1 to 3 had excellent initial capacity and lifespan characteristics, such as an initial capacity of 180 mAh / g or more and no short circuit even after a cycle test of 250 or more times.

[0171] While the present invention has been described with reference to the attached drawings, it should be understood that the present invention may be implemented in other specific forms without altering the technical concept or essential features thereof. Therefore, the embodiments described above should be understood to be illustrative in all respects and not restrictive.

Claims

1. Bipolar layer; cathode layer; A solid electrolyte layer disposed between the anode layer and the cathode layer and including a first solid electrolyte layer adjacent to the anode layer and a second solid electrolyte layer adjacent to the cathode layer; and Including an inert member on the second solid electrolyte layer, An all-solid-state battery, wherein the inert member surrounds a side surface of the positive electrode layer and a side surface of the first solid electrolyte layer.

2. In paragraph 1, The first solid electrolyte layer has a first width and a first thickness, The second solid electrolyte layer has a second width and a second thickness, The above second width is larger than the above first width, An all-solid-state battery, wherein the second thickness is greater than the first thickness.

3. In paragraph 1, An all-solid-state battery, wherein the thickness t3 of the inert member is less than or equal to the sum of the thickness t4 of the positive electrode layer and the thickness t1 of the first solid electrolyte layer.

4. In paragraph 1, The above inert member is a flame retardant inert member, The above flame retardant inert member comprises a matrix and a filler, The above matrix includes a substrate and a reinforcing material, An all-solid-state battery, wherein the substrate comprises a first fibrous material, the first fibrous material being an insulating material, and the first fibrous material comprising at least one selected from pulp fibers, insulating polymer fibers, and ion-conducting polymer fibers.

5. In paragraph 4, An all-solid-state battery wherein the reinforcing material comprises a second fibrous material, the second fibrous material being a flame retardant material, and the second fibrous material comprises at least one selected from glass fibers and ceramic fibers.

6. In paragraph 4, The above filler is a moisture getter, The above filler contains a metal hydroxide, An all-solid-state battery, wherein the metal hydroxide comprises at least one selected from Mg(OH)2, Fe(OH)3, Sb(OH)3, Sn(OH)4, TI(OH)3, Zr(OH)4, and Al(OH)3.

7. In paragraph 1, The above solid electrolyte layer includes a sulfide-based solid electrolyte, The above sulfide-based solid electrolyte is an argyrodite-type solid electrolyte containing at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I. An all-solid-state battery wherein the density of the above-mentioned argyrodite-type solid electrolyte is 1.5 g / cc to 2.0 g / cc.

8. In paragraph 1, The above negative electrode layer includes a negative electrode current collector and a negative electrode coating layer on the negative electrode current collector, The second solid electrolyte layer is in direct contact with the cathode coating layer, and is an all-solid-state battery.

9. In paragraph 8, The above cathode coating layer: At least one metal 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); and An all-solid-state battery comprising at least one carbon selected from the group consisting of carbon black, acetylene black, furnace black, ketjen black, and graphene.

10. In paragraph 8, An all-solid-state battery, wherein the negative electrode layer further includes a lithium metal layer between the negative electrode current collector and the negative electrode coating layer.

11. 1st Monocell; A second monocell on the first monocell; and Including inert elements, The second monocell is arranged symmetrically vertically with respect to the first monocell, Each of the first and second monocells includes a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, The positive electrode layer of the first monocell and the positive electrode layer of the second monocell face each other, The solid electrolyte layer of each of the first and second monocells includes a first solid electrolyte layer adjacent to the positive electrode layer and a second solid electrolyte layer adjacent to the negative electrode layer, The inert member is disposed between the second solid electrolyte layer of the first monocell and the second solid electrolyte layer of the second monocell, An all-solid-state battery, wherein the inert member surrounds a side of the positive electrode layer of each of the first and second monocells and a side of the first solid electrolyte layer of each of the first and second monocells.

12. In paragraph 11, The thickness t3 of the above inert member satisfies the following equation 1, an all-solid-state battery: [Formula 1] t1+t 4 < t 3 ≤ 2 * ( t1+t 4) t1 is the thickness of the first solid electrolyte layer, t4 is the thickness of the above anode layer.

13. In paragraph 11, An all-solid-state battery, wherein the inert member comprises a first inert member adjacent to the second solid electrolyte layer of the first monocell and a second inert member adjacent to the second solid electrolyte layer of the second monocell.

14. In paragraph 13, An all-solid-state battery, wherein the thickness t3 of the first inert member is less than or equal to the sum of the thickness t4 of the positive electrode layer and the thickness t1 of the first solid electrolyte layer.

15. In paragraph 11, The first solid electrolyte layer has a first width and a first thickness, The second solid electrolyte layer has a second width and a second thickness, The above second width is larger than the above first width, An all-solid-state battery, wherein the second thickness is greater than the first thickness.

16. In paragraph 11, An all-solid-state battery further comprising an elastic member disposed on at least one surface of the cathode layer.

17. In paragraph 11, The above inert member is a flame retardant inert member, The above flame retardant inert member comprises a matrix and a filler, The above matrix includes a substrate and a reinforcing material, An all-solid-state battery, wherein the substrate comprises a first fibrous material, the first fibrous material being an insulating material, and the first fibrous material comprising at least one selected from pulp fibers, insulating polymer fibers, and ion-conducting polymer fibers.

18. In paragraph 17, The reinforcing material comprises a second fibrous material, wherein the second fibrous material is a flame retardant material, and wherein the second fibrous material comprises at least one selected from glass fibers and ceramic fibers. The above filler is a moisture getter, The above filler contains a metal hydroxide, An all-solid-state battery, wherein the metal hydroxide comprises at least one selected from Mg(OH)2, Fe(OH)3, Sb(OH)3, Sn(OH)4, TI(OH)3, Zr(OH)4, and Al(OH)3.

19. Laminating a first solid electrolyte layer on a positive electrode layer and then applying a first pressure to form a positive electrode laminate; Laminating a second solid electrolyte layer on a cathode layer and then applying a second pressure to form a cathode laminate; Combining the positive electrode laminate and the negative electrode laminate so that the first solid electrolyte layer and the second solid electrolyte layer are in contact with each other; and Including forming an inert member surrounding the side surface of the positive electrode layer and the side surface of the first solid electrolyte layer on the second solid electrolyte layer, A method for manufacturing an all-solid-state battery, wherein the first pressure is greater than the second pressure.

20. In paragraph 19, Forming the above-described bipolar laminate includes laminating a first functional layer on the first solid electrolyte layer before applying the first pressure, Forming the above cathode laminate includes laminating a second functional layer on the second solid electrolyte layer before applying the second pressure, A method for manufacturing an all-solid-state battery, further comprising removing the first functional layer and the second functional layer before combining the positive electrode laminate and the negative electrode laminate.

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