All-solid-state battery

Abstract

An all-solid-state battery disclosed includes: a laminate including a solid electrolyte layer, an electrode layer stacked in a first direction with the solid electrolyte layer interposed therebetween, and a margin layer in contact with the electrode layer in a second direction intersecting the first direction; and an external electrode disposed outside of the laminate and electrically connected to the electrode layer, in which the electrode layer may include a current collector having a first surface and a second surface opposing the first surface, a first active material layer disposed on the first surface of the current collector, and a second active material layer disposed on the second surface of the current collector, and outermost points in the second direction where the first active material layer, the current collector, and the second active material layer are in contact with the margin layer may be, in a listed order, farther from the external electrode.

Description

ALL-SOLID-STATE BATTERY

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

[0002] Recently, as portable electronic devices are required to be miniaturized and used for long periods of time, high-capacity batteries are required, and as wearable electronic devices become widespread, the safety of batteries is required to be secured.

[0003] Lithium-ion batteries currently on the market use an electrolyte solution containing a flammable organic solvent, so there is a possibility of overheating and fire when a short circuit occurs. Accordingly, an all-solid-state battery using a solid electrolyte instead of the electrolyte solution has been proposed.

[0004] If electrode layers of the all-solid-state battery, that is, a positive electrode layer and a negative electrode layer come into contact, a defect may occur due to a short circuit, and if there is a portion where the positive electrode layer and the negative electrode layer are locally very close to each other, defects may occur due to current leakage or micro short. An electrode margin portion, which is a portion where the positive electrode layer and the negative electrode layer do not overlap, is a portion where electrode short circuits easily occur, so a method for suppressing electrode short circuits in this portion is required.

[0005] The present disclosure attempts to provide an all-solid-state battery capable of preventing an electrode short circuit at an electrode margin portion.

[0006] However, problems to be solved by the embodiments of the present disclosure are not limited to the abovementioned problems, and can be variously expanded within the scope of the technical idea of the present disclosure.

[0007] According to an embodiment, an all-solid-state battery includes: a laminate including a solid electrolyte layer, an electrode layer stacked in a first direction with the solid electrolyte layer interposed therebetween, and a margin layer in contact with the electrode layer in a second direction intersecting the first direction; and an external electrode disposed outside of the laminate and electrically connected to the electrode layer, in which the electrode layer may include a current collector having a first surface and a second surface opposing the first side, a first active material layer disposed on the first surface of the current collector, and a second active material layer disposed on the second surface of the current collector, and outermost points in the second direction where the first active material layer, the current collector, and the second active material layer are in contact with the margin layer may be, in a listed order, farther from the external electrode.

[0008] The first active material layer may comprise a first interface with the margin layer.

[0009] The first interface may comprise an acute angle with the solid electrolyte layer in contact with the first active material layer.

[0010] The first interface may connect a first point where the first active material layer, the margin layer, and the solid electrolyte layer meet, and a second point where the first active material layer, the current collector, and the margin layer meet.

[0011] The current collector may comprise a second interface with the margin layer.

[0012] The second interface may comprise an acute angle with the solid electrolyte layer in contact with the first active material layer.

[0013] The second interface may connect the second point and a third point which is an outermost point in the second direction where the current collector is in contact with the margin layer.

[0014] The current collector may further comprise a third interface with the margin layer and the third interface may comprise an acute angle with the second interface.

[0015] The third interface may connect the third point and a fourth point where the second active material layer, the current collector, and the margin layer meet.

[0016] The second active material layer may comprise a fourth interface with the margin layer.

[0017] The fourth interface may comprise an acute angle with the solid electrolyte layer in contact with the first active material layer.

[0018] The fourth interface may connect the fourth point and a fifth point where the second active material layer, the solid electrolyte layer, and the margin layer meet.

[0019] The first active material layer may comprise a first interface with the margin layer, the current collector may comprise a second interface with the margin layer and a third interface comprising an acute angle with the second interface, respectively, the second active material layer may comprise a fourth interface with the margin layer, satisfying Formula 1.

[0020] [Formula 1]

[0021] 0.5 ≤ w1 / (w1 + w2) ≤ 0.85

[0022] where,

[0023] w1: width of the first interface

[0024] w2: width of the second interface

[0025] The second interface may connect a second point where the first active material layer, the current collector, and the margin layer meet, and a third point which is the outermost point in the second direction where the current collector is in contact with the margin layer, the third interface may connect the third point and a fourth point where the second active material layer, the current collector, and the margin layer meet, further satisfying Formula 2.

[0026] [Formula 2]

[0027] 0.15 ≤ (w3 + d1) / (w1 + w2) ≤ 0.5

[0028] where,

[0029] w3: width of the third interface

[0030] d1: gap between the second and fourth points

[0031] The all-solid-state battery may further satisfy Formula 3.

[0032] [Formula 3]

[0033] 0.5 ≤ w3 / d1 ≤ 1

[0034] The margin layer may include a first margin layer in contact with the first active material layer and the current collector, and a second margin layer in contact with the first margin layer, the current collector, and the second active material layer.

[0035] An ion conductivity of the solid electrolyte included in the solid electrolyte layer may be 10-6S / cm or more.

[0036] The margin layer may include an insulating material.

[0037] The ion conductivity of the insulating material may be 10-6S / cm or less.

[0038] According to an embodiment, an electrode for an all-solid-state battery, includes: an electrode layer including: a current collector having a first surface and a second surface opposing the first surface in a thickness direction, a first active material layer disposed on the first surface, and a second active material layer disposed on the second surface; and a margin portion disposed between a first of a pair of longitudinally opposing edges of the electrode layer and a first external electrode of the all-solid-state battery, in which a second of the pair of longitudinally opposing edges of the electrode layer contacts a second external electrode of the all-solid-state battery, and a distance, in the longitudinal direction, between the first external electrode and points at which the first active material layer, the current collector, and the second active material layer contact the margin portion is sequentially greater.

[0039] According to the all-solid-state battery according to the embodiment, it is possible to prevent electrode short circuits at electrode margin portions.

[0040] FIG. 1 is a perspective view schematically illustrating an all-solid-state battery according to an embodiment.

[0041] FIG. 2 is a perspective view schematically illustrating a laminate of the all-solid-state battery of FIG. 1.

[0042] FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1.

[0043] FIG. 4 is an enlarged view of area S in FIG. 3.

[0044] FIG. 5A is an enlarged view of area A of FIG. 3.

[0045] FIG. 5B is a diagram schematically illustrating a case where a positive electrode margin portion of FIG. 5A is curved.

[0046] FIG. 6A is an enlarged view of area B of FIG. 3.

[0047] FIG. 6B is a diagram schematically illustrating the case where a negative electrode margin portion of FIG. 6A is curved.

[0048] FIG. 7 is a schematic cross-sectional view for describing a structure of a positive electrode layer and a margin layer of the all-solid-state battery of FIG. 1.

[0049] FIG. 8 is a schematic diagram for describing a method for forming a positive electrode layer and a margin layer of an all-solid-state battery according to an embodiment.

[0050] FIG. 9 is a schematic cross-sectional view for describing a structure formed by a positive electrode layer and a margin layer of an all-solid-state battery according to Comparative Example.

[0051] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present disclosure pertains may easily practice the present disclosure. The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification. In addition, it is to be noted that some components shown in the drawings are exaggerated, omitted or schematically illustrated, and the size of each component does not exactly reflect its real size.

[0052] It should be understood that the accompanying drawings are provided only in order to allow embodiments of the present disclosure to be easily understood, and the spirit of the present disclosure is not limited by the accompanying drawings, but includes all the modifications, equivalents, and substitutions included in the spirit and the scope of the present disclosure.

[0053] Terms including an ordinal number such as first, second, etc., may be used to describe various components, but the components are not limited to these terms. The above terms are used solely for the purpose of distinguishing one component from another.

[0054] In addition, it will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. In addition, when an element is referred to as being "on" a reference element, it can be positioned on or beneath the reference element, and is not necessarily positioned on the reference element in an opposite direction to gravity.

[0055] Throughout the specification, it will be further understood that terms "include" or "have" used in the present specification specify the presence of features, numerals, steps, operations, components, parts mentioned in the present specification, or combinations thereof, but do not preclude the presence or addition of one or more other features, numerals, steps, operations, components, parts, or combinations thereof. Accordingly, unless explicitly described to the contrary, "comprising" any components will be understood to imply the inclusion of other components rather than the exclusion of any other components.

[0056] Further, throughout the specification, the word "plan view" refers to a view when a target is viewed from the top, and the word "cross-sectional view" refers to a view when a cross section of a target taken along a vertical direction is viewed from the side.

[0057] In addition, throughout the specification, when it is said to be "connected", this does not only mean that two or more components are directly connected, but may mean that two or more components are indirectly connected through another component, that two or more components are physically connected as well as electrically connected, or that two or more components are referred to by different names depending on their location or function, but are integral.

[0058] FIG. 1 is a perspective view schematically illustrating an all-solid-state battery according to an embodiment. FIG. 2 is a perspective view schematically illustrating a laminate of the all-solid-state battery of FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1.

[0059] Referring to FIGS. 1, 2, and 3, an all-solid-state battery 1000 according to the present embodiment includes a laminate 100, a first external electrode 300, and a second external electrode 400.

[0060] First, when defining directions to clearly describe the present embodiment, an L-axis, a W-axis, and a T-axis illustrated in the drawings represent axes representing a length direction, a width direction, and a thickness direction of the all-solid-state battery 1000, respectively.

[0061] The thickness direction (T-axis direction) may be a direction perpendicular to a wide surface (main surface) of sheet-shaped components. For example, the thickness direction (T-axis direction) may be used as the same concept as a direction in which components of the laminate 100 are stacked.

[0062] The length direction (L-axis direction) is a direction parallel to the wide surface (main surface) of the sheet-shaped components and may be a direction that intersects (or is perpendicular to) the thickness direction (T-axis direction). For example, the length direction (L-axis direction) may be a direction in which a first external electrode 300 and a second external electrode 400 oppose each other.

[0063] The width direction (W-axis direction) is a direction parallel to the wide surface (main surface) of the sheet-shaped components and may be a direction that simultaneously intersects (or is orthogonal to) the thickness direction (T-axis direction) and the length direction (L-axis direction).

[0064] The laminate 100 may have a substantially hexahedral shape, but the present embodiment is not limited thereto. Due to shrinkage during sintering, the laminate 100 may not have a completely hexahedral shape, but have a substantially hexahedral shape. For example, the laminate 100 has a substantially rectangular shape, but a portion corresponding to a corner or vertex may have a rounded shape.

[0065] In the present embodiment, for convenience of description, surfaces opposing each other in the length direction (L-axis direction) are defined as a first surface S1 and a second surface S2, surfaces opposing each other in the width direction (W-axis direction) and connecting the first surface S1 and the second surface S2 are defined as a third surface S3 and a fourth surface S4, and surfaces opposing each other in the thickness direction (T-axis direction) and connecting the first surface S1 and the second surface S2 are defined as a fifth surface S5 and a sixth surface S6.

[0066] Accordingly, a first direction in which the first surface S1 and the second surface S2 oppose each other may be the length direction (L-axis direction), and the second and third directions perpendicular to the first direction and perpendicular to each other may be the thickness direction (T-axis direction) and the width direction (W-axis direction), or the width direction (W-axis direction) and the thickness direction (T-axis direction), respectively.

[0067] A length of the laminate 100 may refer to, based on an optical microscope photograph or scanning electron microscope (SEM) photograph of a cross-section taken along the length direction (L-axis direction)-thickness direction (T-axis direction) at a central portion of the laminate 100 in the width direction (W-axis direction), a maximum value among lengths of a plurality of line segments that respectively connect two opposing outermost boundary lines in the length direction (L-axis direction) of the laminate 100 shown in the above-described cross-sectional photograph and are parallel to the length direction (L-axis direction). Meanwhile, the length of the laminate 100 may refer to a minimum value among the plurality of line segments that respectively connect the two opposing outermost boundary lines in the length direction (L-axis direction) of the laminate 100 shown in the above-described cross-sectional photograph and are parallel to the length direction (L-axis direction). On the other hand, the length of the laminate 100 may refer to an arithmetic average value of at least two of the plurality of line segments that respectively connect the two opposing outermost boundary lines in the length direction (L-axis direction) of the laminate 100 shown in the above-described cross-sectional photograph and are parallel to the length direction (L-axis direction).

[0068] A thickness of the laminate 100 may refer to, based on an optical microscope photograph or scanning electron microscope (SEM) photograph of a cross-section taken along the length direction (L-axis direction)-thickness direction (T-axis direction) at a central portion of the laminate 100 in the width direction (W-axis direction), a maximum value among lengths of a plurality of line segments that respectively connect two outermost boundary lines opposing in the thickness direction (T-axis direction) of the laminate 100 shown in the above-described cross-sectional photograph and are parallel to the thickness direction (T-axis direction). Meanwhile, the thickness of the laminate 100 may refer to a minimum value among a plurality of line segments that respectively connect the two outermost boundary lines opposing in the thickness direction (T-axis direction) of the laminate 100 shown in the above-described cross-sectional photograph and are parallel to the thickness direction (T-axis direction). On the other hand, the thickness of the laminate 100 may refer to an arithmetic average value of lengths of at least two of a plurality of line segments that respectively connect the two outermost boundary lines opposing in the thickness direction (T-axis direction) of the laminate 100 shown in the above-described cross-sectional photograph and are parallel to the thickness direction (T-axis direction).

[0069] A width of the laminate 100 may refer to, based on an optical microscope photograph or scanning electron microscope (SEM) photograph of a cross-section taken along the length direction (L-axis direction)-width direction (W-axis direction) at a central portion of the laminate 100 in the thickness direction (T-axis direction), a maximum value among lengths of a plurality of line segments that respectively connect two outermost boundary lines opposing in the width direction (W-axis direction) of the laminate 100 shown in the above-described cross-sectional photograph and are parallel to the width direction (W-axis direction). Meanwhile, the width of the laminate 100 may refer to a minimum value among a plurality of line segments that respectively connect the two outermost boundary lines opposing in the width direction (W-axis direction) of the laminate 100 shown in the above-described cross-sectional photograph and are parallel to the width direction (W-axis direction). On the other hand, the width of the laminate 100 may refer to an arithmetic average value of lengths of at least two of a plurality of line segments that respectively connect the two outermost boundary lines opposing in the width direction (W-axis direction) of the laminate 100 shown in the above-described cross-sectional photograph and are parallel to the width direction (W-axis direction).

[0070] The laminate 100 may include a solid electrolyte layer 110, a positive electrode layer 130, a negative electrode layer 150, an upper protective layer 160, a lower protective layer 170, and a margin layer 180.

[0071] The solid electrolyte layer 110, the positive electrode layer 130, and the negative electrode layer 150 each be plural, and the positive electrode layer 130 and the negative electrode layer 150 may be alternately stacked in the thickness direction (T-axis direction) with the solid electrolyte layer 110 interposed therebetween.

[0072] The positive electrode layer 130 may be disposed on one surface of the solid electrolyte layer 110, and the negative electrode layer 150 may be disposed on the other surface of the solid electrolyte layer 110.

[0073] The solid electrolyte layer 110 includes the solid electrolyte. The solid electrolyte may serve as a passageway for lithium (Li) ions.

[0074] For example, the ionic conductivity of the solid electrolyte may be 10-6S / cm or more.

[0075] The solid electrolyte included in the solid electrolyte layer 110 may include a glass-ceramic-based electrolyte containing lithium halide (LiX, wherein X is a halogen element such as F, Br, Cl, I, etc.). The glass-ceramic (or crystallization glass) refers to that a crystallographic mixture of amorphous and crystalline materials from which peaks and halos are observed in X-ray diffraction, electron beam diffraction, etc.. Therefore, the glass-ceramic-based electrolyte is an electrolyte that has undergone partial crystallization through sintering and in which amorphous and crystalline materials are mixed.

[0076] The glass-ceramic-based electrolyte may include a mixture of an amorphous material and two or more types of crystalline materials. In addition, the crystalline material included in the glass-ceramic-based electrolyte may include a lithium compound crystalline phase containing lithium.

[0077] When the glass-ceramic-based electrolyte is included in the solid electrolyte layer 110, sufficient densification is achieved after sintering, whereby it is possible to realize high ionic conductivity.

[0078] As an example, the glass-ceramic-based electrolyte may include a lithium-chloroboracite-based electrolyte. As a specific example, the glass-ceramic-based electrolyte may contain Li2O-B2O3-LiCl-Al2O3.

[0079] As another example, the solid electrolyte included in the solid electrolyte layer 110 may contain a lithium-borosilicate-based electrolyte (hereinafter, referred to as LBSO-based electrolyte). The LBSO-based electrolyte is a glass-state electrolyte, and glass refers to a crystallographically amorphous material, from which halos are observed in the X-ray diffraction or electron beam diffraction.

[0080] When the LBSO-based electrolyte is included in the solid electrolyte layer 110, it is possible to keep the amorphous state during sintering while lowering the sintering temperature.　 Therefore, there is an advantage that it is possible to realize high ionic conductivity, and reactivity with the electrode is not high. The LBSO-based electrolyte may include lithium (Li), boron (B), silicon (Si), aluminum (Al), phosphorus (P), germanium (Ge), and sulfur (S).

[0081] Alternatively, the solid electrolyte included in the solid electrolyte layer 110 may be one or more types selected from the group consisting of a Garnet-type, a Na super ionic conductor (NASICON)-type, a lithium super ionic conductor (LISICON)-type, a Perovskite-type, and a lithium phosphorus oxynitride (LiPON)-type.

[0082] In region where the positive electrode margin portion 132 and negative electrode margin portion 152 are disposed, which will be described later, a material having low ionic conductivity and low electrical conductivity, that is, an insulating material, may be present, or a material having ionic conductivity (or electrical conductivity) similar to the ionic conductivity (or electrical conductivity) of the solid electrolytes may be present. For example, when the material having ionic conductivity (or electrical conductivity) similar to the ionic conductivity (or electrical conductivity) of the solid electrolyte is present in this region, the material may be a material identical to or different from the solid electrolyte in other regions. In another example, a material having ionic conductivity (or electrical conductivity) similar to the ionic conductivity (or electrical conductivity) of the solid electrolyte and an insulating material may coexist together in the region.

[0083] The Garnet-type solid electrolyte may refer to lithium lanthanum zirconium oxide (LLZO) represented by LiaLabZrcO12such as Li7La3Zr2O12, and the NASICON-type solid electrolyte may include lithium-aluminum-titanium-phosphate (LATP) of Li1+xAlxTi2-x(PO4)3(wherein 0<x<1) produced by introducing Ti to Li1+xAlxM2-x(PO4)3(LAMP) (wherein 0<x<2, M is Zr, Ti, or Ge)-type compound, lithium-aluminum-germanium-phosphate (LAGP) represented by Li1+xAlxGe2-x(PO4)3(wherein 0<x<1), such as Li1.3Al0.3Ge1.7(PO4)3containing an excessive amount of lithium, and / or lithium-zirconium-phosphate (LZP) of LiZr2(PO4)3.

[0084] In addition, the LISICON-based solid electrolyte may include solid solution oxide represented by xLi3AO4-(1-x)Li4BO4(wherein A is P, As, V, etc., and B is Si, Ge, Ti, etc.), such as Li4Zn(GeO4)4, Li10GeP2O12(LGPO), Li3.5Si0.5P0.5O4, and Li10.42Si(Ge)1.5P1.5Cl0.08O11.92, etc., and solid solution sulfide represented by Li4-xM1-yM'yS4(wherein M is Si or Ge and M' is P, Al, Zn, or Ga), such as Li2S-P2S5, Li2S-SiS2, Li2S-SiS2-P2S5, or Li2S-GeS2.

[0085] Further, the Perovskite-type solid electrolyte may include lithium lanthanum titanate (LLTO) represented by Li3xLa2 / 3-x□1 / 3-2xTiO3(wherein 0<x<0.16, and □ is vacancy), such as Li1 / 8La5 / 8TiO3, and the LiPON-type solid electrolyte may include nitride such as lithium phosphorous oxynitride of Li2.8PO3.3N0.46.

[0086] The positive electrode layer 130 may be exposed outside of the laminate 100 from the first surface S1 of the laminate 100, and may be connected to the first external electrode 300.

[0087] Referring to FIG. 4, the positive electrode layer 130 may include a positive electrode current collector 133, a first positive electrode active material layer 135, and a second positive electrode active material layer 136.

[0088] For example, the positive electrode current collector 133 may be made of a plate-shape member or a thin member. As another example, the positive electrode current collector 133 may be a porous body having a reticulate shape, a mesh shape, or the like.

[0089] The positive electrode current collector 133 may include a first surface 133a and a second surface 133b. The first surface 133a and the second surface 133b oppose each other in the thickness direction (T-axis direction).

[0090] The positive electrode current collector 133 may include, but not limited to, a porous metal plate made of stainless steel, nickel (Ni), copper (Cu), tin (Sn), aluminum (Al), or an alloy thereof.

[0091] In addition, the positive electrode current collector 133 may be coated with an oxidation-resistant metal or alloy film to prevent oxidation.

[0092] The positive electrode current collector 133 may include a carbon-based plate-shaped, thin, or linear member. The positive electrode current collector 133 may include a conductive carbon material. The conductive carbon material may include graphite, conductive fiber such as carbon nanotube (CNT) or vapor grown carbon fiber (VGCF), or conductive carbon such as carbon black.

[0093] Meanwhile, the positive electrode current collector may also include one or more types of solid electrolyte.

[0094] The first positive electrode active material layer 135 and the second positive electrode active material layer 136 may include positive electrode active materials, and may be disposed on a surface of the positive electrode current collector 133. The first positive electrode active material layer 135 may be in contact with the first surface 133a of the positive electrode current collector 133, and the second positive electrode active material layer 136 may be in contact with the second surface 133b of the positive electrode current collector 133. The positive electrode active material layer 135 may be formed by printing a positive electrode active material on one or both sides of the positive electrode current collector 133, but the method for forming the positive electrode active material layer is not limited thereto.

[0095] The positive electrode active material included in the positive electrode active material layer 135 may comprise a material containing lithium (Li) ions. The positive electrode active material may reversibly intercalate and deintercalate lithium ions. In other words, the positive electrode active material may contain lithium ions and serve to provide the lithium ions to the negative electrode when the all-solid-state battery is being charged. The positive electrode active material may affect the capacity and output of the all-solid-state battery

[0096] For example, the positive electrode active material may include at least one selected from the group consisting of compounds represented by the following formula: LiaAl-bMbD2(where, 0.90≤a≤1.8, 0≤b≤0.5); LiaEl-bMbO2-cDc(where, 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiE2-bMbO4-cDc(where, 0≤b≤0.5, 0≤c≤0.05); LiaNi1-b-cCobMcDα(where, 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2); LiaNi1-b-cCobMcO2-αXα(where, 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); LiaNi1-b-cCobMcO2-αX2(where, 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05,0<α<2); LiaNi1-b-cMnbMcDα(where, 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2); LiaNi1-b-cMnbMcO2-αXα(where,0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); LiaNi1-b-cMnbMcO2-αX2(where, 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); LiaNibEcGdO2(where, 0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1); LiaNibCocMndGeO2(where,0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0.001≤e≤0.1); LiaNiGbO2(where, 0.90≤a≤1.8, 0.001≤b≤0.1); LiaCoGbO2(where, 0.90≤a≤1.8, 0.001≤b≤0.1); LiaMnGbO2 (where, 0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn2GbO4(where, 0.90≤a≤1.8, 0.001≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O2; LiRO2; LiNiVO4; Li(3-f)J2(PO4)3(0≤f≤2); Li(3-f)Fe2(PO4)3(where, 0≤f≤2); and LiFePO4. In the above chemical formulas, A represents Ni, Co, or Mn; M represents Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, Nb, Ti or a rare-earth element; D represents O, F, S, or P; E represents Co or Mn; X represents F, S, or P; G represents Al, Cr, Mn, Fe, Mg, La, Ce, Sr, or V; Q represents Ti, Mo or Mn; R represents Cr, V, Fe, Sc, or Y; and J represents V, Cr, Mn, Co, Ni, or Cu.

[0097] The positive electrode active material may also include LiCoO2, LiMnxO2x(where, x is 1 or 2), LiNi1-xMnxO2x(where, 0<x<1), LiNi1-x-yCoxMnyO2(where, 0≤x≤0.5 and 0≤y≤0.5), LiFePO4, TiS2, FeS2, TiS3, or FeS3, but is not limited thereto.

[0098] The positive electrode active material may optionally include a conductive material and a binder. However, because an organic substance such as a binder decomposes during sintering process, the organic material may not remain on the positive electrode active material layer of the obtained positive electrode current collector.

[0099] The conductive material is not particularly limited as long as it has conductivity without causing chemical changes in the all-solid-state battery 1000. For example, graphite such as natural graphite and artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjenblack®, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers, metal fibers, etc.; carbon fluoride; metal components such as lithium (Li), tin (Sn), aluminum (Al), nickel (Ni), copper (Cu), etc., oxides thereof, nitrides thereof, or fluorides thereof; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives, etc., may be used.

[0100] The binder may be used to improve the bonding strength of the active material, the conductive material, or the like. The binder may include, but not limited to, at least one selected from the group consisting of polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber (SBR), fluorine rubber, various copolymers, etc..

[0101] Meanwhile, the positive electrode layer 130 may further contain a solid electrolyte component. The solid electrolyte component may contain one or more of the above-described components, and may serve as an ionic conduction channel in the positive electrode layer. Therefore, it is possible to reduce interface resistance.

[0102] The negative electrode layer 150 may be exposed outside of the laminate 100 from the second surface S2 of the laminate 100, and may be connected to the second external electrode 400.

[0103] Referring to FIG. 4, the negative electrode layer 150 may include a negative electrode current collector 153, a first negative electrode active material layer 155, and a second negative electrode active material layer 156.

[0104] For example, the negative electrode current collector 153 may include a plate-shaped member or a thin member. As another example, the negative electrode current collector 153 may include a porous body having a reticulate shape, a mesh shape, or the like.

[0105] The negative electrode current collector 153 may include a first surface 153a and a second surface 153b. The first surface 153a and the second surface 153b oppose each other in the thickness direction (T-axis direction).

[0106] For example, the negative electrode current collector 153 may include, but not limited to, a porous metal plate made of stainless steel, nickel (Ni), copper (Cu), tin (Sn), aluminum (Al), or an alloy thereof.

[0107] In addition, the negative electrode current collector 153 may be coated with an oxidation-resistant metal or alloy film to prevent oxidation.

[0108] The negative electrode current collector 153, like the positive electrode current collector 133, may include a conductive carbon-based material, and may include one or more types of solid electrolytes. The negative electrode current collector 153 may be identical to the negative electrode active material layers 155 and 156.

[0109] The first negative electrode active material layer 155 and the second negative electrode active material layer 156 may include negative electrode active materials and be disposed on a surface of the negative electrode current collector 153. The first negative electrode active material layer 155 may be in contact with the first surface 153a of the negative electrode current collector 153, and the second negative electrode active material layer 156 may be in contact with the second surface 153b of the negative electrode current collector 153. The negative electrode active material layer 155 may be formed by printing a negative electrode active material on one or both surfaces of the negative electrode current collector 153. However, the method for forming an negative electrode active material layer is not limited thereto.

[0110] The negative electrode active material in the negative electrode active material layer 155 may store the lithium ions that have moved from the positive electrode and release the lithium ions when the all-solid-state battery is discharged, thereby generating electrical energy. A carbon-based material, silicon, a silicon oxide, a silicon-based alloy, a silicon-carbon-based material composite, tin, a tin-based alloy, a tin-carbon composite, a metal oxide, or a combination thereof may be used as the negative electrode active material. The negative electrode active material may contain a lithium metal and / or a lithium metal alloy.

[0111] The lithium metal alloy may contain lithium, and a metal / metalloid capable of making an alloy with lithium. For example, the metal / metalloid capable of making an alloy with lithium may include Si, Sn, Al, Ge, Pb, Bi, Sb, and Si-AM alloy (wherein AM is an alkali metal, an alkaline earth metal, an element in group 13 to 16, a transition metal, a rare-earth element, or a combination thereof, and does not include Si), Sn-AM alloys (wherein AM is an alkali metal, an alkaline earth metal, an element in group 13 to 16, a transition metal, a transition metal oxide such as lithium titanium oxide (Li4Ti5O12), a rare-earth element, or combinations thereof, and does not include Sn), MnOx(wherein 0<x≤2), and the like.

[0112] The element AM may include Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, or combinations thereof.

[0113] In addition, the oxide of the metal / metalloid capable of making an alloy with lithium may include lithium titanium oxide, vanadium oxide, lithium vanadium oxide, SnO2, SiOx(wherein 0<x<2), or the like. For example, the negative electrode active material may include one or more elements selected from the group consisting of the elements in group 13 to 16 of the periodic table of elements. For example, the negative electrode active material may contain one or more elements selected from the group consisting of Si, Ge, and Sn.

[0114] The carbon-based material may include crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon may be graphite such as natural graphite or artificial graphite that is in a shapeless, disc-shaped, flake-shaped, globular, or fibrous form. In addition, the amorphous carbon may include, but not limited to, soft carbon (low-temperature calcined carbon), hard carbon, mesophase pitch carbide, calcined cokes, graphene, carbon black, fullerene soot, carbon nanotube, carbon fiber, etc..

[0115] The silicon may include at least one selected from the group consisting of Si, SiOx(wherein 0<x<2, for example, 0.5 to 1.5), Sn, SnO2, or silicon-containing metal alloy, and mixtures thereof. For example, the silicon-containing metal alloy may include silicon, and one or more of Al, Sn, Ag, Fe, Bi, Mg, Zn, in, Ge, Pb, or Ti.

[0116] The negative electrode active material may optionally include a conductive material and a binder.

[0117] The conductive material is not particularly limited as long as it has conductivity without causing chemical changes in the all-solid-state battery 1000. For example, graphite such as natural graphite and artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjenblack®, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers, metal fibers, etc.; carbon fluoride; metal components such as lithium (Li), tin (Sn), aluminum (Al), nickel (Ni), copper (Cu), etc., oxides thereof, nitrides thereof, or fluorides thereof; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives, etc., may be used.

[0118] The binder may be used to improve the bonding strength of the active material, the conductive material, or the like. The binder may include, but not limited to, at least one selected from the group consisting of polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber (SBR), fluorine rubber, various copolymers, etc..

[0119] Hereinafter, the positive electrode layer and the negative electrode layer will be further described with reference to FIGS. 5A, 5B, 6A, and 6B. FIG. 5A is an enlarged view of area A of FIG. 3. FIG. 5B is a diagram schematically illustrating a case where a positive electrode margin portion of FIG. 5A is curved. FIG. 6A is an enlarged view of area B of FIG. 3. FIG. 6B is a diagram schematically illustrating the case where an negative electrode margin portion of FIG. 6A is curved.

[0120] Referring to FIGS. 3 and 5A, the positive electrode layer 130 includes a positive electrode body 131 and a positive electrode margin portion 132.

[0121] The positive electrode body 131 is a portion where the positive electrode layer 130 overlaps with the negative electrode layer 150 in the thickness direction (T-axis direction). A first end 137 of the positive electrode body 131 in the length direction (L-axis direction) is in contact with the margin layer 180.

[0122] The positive electrode margin portion 132 is a portion that extends from the positive electrode body 131 but does not overlap with the negative electrode layer 150. A second end 139 of the positive electrode margin portion 132 in the length direction (L-axis direction) is in contact with the first external electrode 300.

[0123] The positive electrode margin portion 132 may be deformed and inclined relative to the positive electrode body 131 by the pressure applied during the process of forming the laminate 100. That is, the positive electrode margin portion 132 may be disposed to intersect an imaginary extension line E1 of the positive electrode body 131. An outer angle θ1, i.e., an angle formed by the positive electrode margin portion 132 with the imaginary extension line E1 of the positive electrode body 131 may be an acute angle. Here, the outer angle θ1 is an absolute value. That is, the positive electrode margin portion 132 may be inclined toward the fifth surface S5 or the sixth surface S6 of the laminate 100, with respect to the imaginary extension line E1 of the positive electrode body 131.

[0124] In addition, the positive electrode layers 130 may be plural, and the size of the outer angle θ1 formed by the positive electrode margin portion 132 and the positive electrode body 131 may be different for each positive electrode layer 130.

[0125] Meanwhile, referring to FIG. 5B, the shape of the positive electrode margin portion 132 may not be a straight line and may be a curved line. In this case, the outer angle θ1 means, when a point where the positive electrode margin portion 132 is connected to the positive electrode body 131 and a point where the positive electrode margin portion 132 is connected to the first external electrode 300 are connected by an imaginary straight line F1, an angle formed between the imaginary straight line F1 and the imaginary extension line E1. The point where the positive electrode margin portion 132 is connected to the first external electrode 300 may be, for example, a point where, among two surfaces opposing each other in the thickness direction (T-axis direction) of the positive electrode margin portion 132, a surface closer to the imaginary extension line E1 is in contact with the first external electrode 300.

[0126] Referring to FIGS. 3 and 6A, the negative electrode layer 150 includes a negative electrode body 151 and a negative electrode margin portion 152.

[0127] The negative electrode body 151 is a portion where the negative electrode layer 150 overlaps with the positive electrode layer 130 in the thickness direction (T-axis direction). A first end 157 of the negative electrode body 151 in the length direction (L-axis direction) is in contact with the margin layer 180.

[0128] The negative electrode margin portion 152 is a portion that extends from the negative electrode body 151 but does not overlap with the positive electrode layer 130. A second end 159 of the negative electrode margin portion 152 in the length direction (L-axis direction) is in contact with the second external electrode 400.

[0129] The negative electrode margin portion 152 may be deformed and inclined relative to the negative electrode body 151 by the pressure applied during the process of forming the laminate 100. That is, the negative electrode margin portion 152 may be disposed to intersect an imaginary extension line E2 of the negative electrode body 151. For example, an outer angle θ2, i.e., an angle formed by the negative electrode margin portion 152 with the imaginary extension line E2 of the negative electrode body 151 may be an acute angle. Here, the outer angle θ2 is an absolute value. That is, the negative electrode margin portion 152 may be inclined toward the fifth surface S5 or the sixth surface S6 of the laminate 100, with respect to the imaginary extension line E2 of the negative electrode body 151.

[0130] In addition, the negative electrode layers 150 may be plural, and the size of the outer angle θ2 formed by the negative electrode margin portion 152 and the negative electrode body 151 may be different for each negative electrode layer 150.

[0131] Meanwhile, referring to FIG. 6B, the shape of the negative electrode margin portion 152 may not be a straight line and may be a curved line. In this case, the outer angle θ2 means, when a point where the negative electrode margin portion 152 is connected to the negative electrode body 151 and a point where the negative electrode margin portion 152 is connected to the second external electrode 400 are connected by an imaginary straight line F2, an angle formed by the imaginary straight line F2 and the imaginary extension line E2. The point where the negative electrode margin portion 152 is connected to the second external electrode 400 may be, for example, a point where, among two surfaces opposing each other in the thickness direction (T-axis direction) of the negative electrode margin portion 152, a surface closer to the imaginary extension line E2 is in contact with the second external electrode 400.

[0132] Referring back to FIG. 3, the positive electrode margin portion 132 is inclined with respect to the positive electrode body 131, and the negative electrode margin portion 152 is inclined with respect to the negative electrode body 151. That is, the outer angle θ1 formed between the positive electrode margin portion 132 and the positive electrode body 131 and the outer angle θ2 formed between the negative electrode margin portion 152 and the negative electrode body 151 may be acute angles.

[0133] Meanwhile, the outer angle θ1 formed between the positive electrode margin portion 132 and the positive electrode body 131 may be the same as or different from the outer angle θ2 formed between the negative electrode margin portion 152 and the negative electrode body 151.

[0134] As described above, since the positive electrode margin portion 132 is inclined with respect to the positive electrode body 131, the positive electrode margin portion 132 may be close to the first end 157 of the negative electrode layer 150. If the first end 157 of the negative electrode layer 150 is deformed and inclined toward the positive electrode margin portion 132 during the process of forming the laminate 100, a short circuit may occur between the positive electrode layer 130 and the negative electrode layer 150. Likewise, since the negative electrode margin portion 152 is inclined with respect to the negative electrode body 151, the negative electrode margin portion 152 may be close to the first end 137 of the positive electrode layer 130. If the first end 137 of the positive electrode layer 130 is deformed and inclined toward the negative electrode margin portion 152 during the process of forming the laminate 100, a short circuit may occur between the negative electrode layer 150 and the positive electrode layer 130. The present embodiment is intended to solve this problem, and a detailed description thereof will be provided later.

[0135] The upper protective layer 160 and the lower protective layer 170 may be outermost layers disposed on the fifth surface S5 and the sixth surface S6 of the laminate 100, respectively. That is, the upper protective layer 160 may be an outermost layer toward the fifth surface S5 of the laminate 100, and the lower protective layer 170 may be an outermost layer toward the sixth surface S6 of the laminate 100. The upper protective layer 160 and the lower protective layer 170 may improve moisture resistance by preventing moisture penetration, and prevent damage from physical and chemical impacts.

[0136] The upper protective layer 160 and the lower protective layer 170 may be an insulation layer made of an insulating material, that is, a material that does not have electrical conductivity (ionic conductivity).

[0137] The upper protective layer 160 and the lower protective layer 170 may include a ceramic material, for example, alumina (Al2O3), aluminum nitride (AlN), beryllium oxide (BeO), boron nitride (BN), silicon (Si), silicon carbide (SiC), silica (SiO2), silicon nitride (Si3N4), gallium arsenide (GaAs), gallium nitride (GaN), barium titanate (BaTiO3), zirconium dioxide (ZrO2), mixtures thereof, oxides and / or nitrides of such materials, or any other suitable ceramic materials, but is not limited thereto. In addition, the upper protective layer 160 and the lower protective layer 170 may selectively include the above-described solid electrolytes, and may include one or more types of solid electrolytes, but are not limited thereto.

[0138] The margin layer 180 may be disposed on the solid electrolyte layer 110 in a region excluding the region where the positive electrode layer 130 and the negative electrode layer 150 is disposed.

[0139] Referring to FIG. 3, the margin layer 180 may comprise a portion of the first surface S1 and a portion of the second surface S2 of the laminate 100. Meanwhile, although not shown, the margin layer 180 may comprise a portion of the third surface S3 and a portion of the fourth surface S4 of the laminate 100.

[0140] The margin layer 180 may be disposed to compensate for a level difference between the solid electrolyte layer 110 and the positive electrode layer 130 and a level difference between the solid electrolyte layer 110 and the negative electrode layer 150. For example, the margin layer 180 may be disposed on the same surface as the positive electrode layer 130 and the negative electrode layer 150. The margin layer 180 may compensate for a level difference between the solid electrolyte layer 110 and the positive electrode layer 130 or a level difference between the solid electrolyte layer 110 and the negative electrode layer 150. This increases the density between the solid electrolyte layer 110 and the electrode layers, which may prevent interlayer delamination or warping caused by sintering during a process of manufacturing the all-solid-state battery.

[0141] The margin layer 180 may include an insulating material, i.e., a material that is not electrically (ionically) conductive. For example, the ionic conductivity of the insulating material may be 10-6S / cm or less.

[0142] The margin layer may include, but not limited to, at least one selected from the group consisting of ceramic materials, e.g., alumina (Al2O3), aluminum nitride (AlN), beryllium oxide (BeO), boron nitride (BN), silicon (Si), silicon carbide (SiC), silica (SiO2), silicon nitride (Si3N4), gallium arsenide (GaAs), gallium nitride (GaN), barium titanate (BaTiO3), zirconium dioxide (ZrO2), mixtures thereof, oxides thereof and / or nitrides thereof, or any other suitable ceramic materials.

[0143] Meanwhile, the margin layer 180 may optionally include the above-described solid electrolyte, and may include one or more types of solid electrolytes, but is not limited thereto.

[0144] In addition, in the margin layer 180, a material having low ionic conductivity and low electrical conductivity, that is, an insulating material, may be present, or a material having ionic conductivity (or electrical conductivity) similar to the ionic conductivity (or electrical conductivity) of the solid electrolyte may be present. For example, when a material having ionic conductivity (or electrical conductivity) similar to the ionic conductivity (or electrical conductivity) of the solid electrolyte is present in the margin layer, the material may be a material that is identical to or different from the solid electrolyte in other regions. In another example, a material having ionic conductivity (or electrical conductivity) similar to the ionic conductivity (or electrical conductivity) of the solid electrolyte and an insulating material may coexist in the margin layer.

[0145] The first external electrode 300 and the second external electrode 400 are disposed outside the laminate 100.

[0146] The first external electrode 300 is connected to the positive electrode layer 130, on the first surface S1 of the laminate 100.

[0147] For example, the first external electrode 300 may extend onto the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the laminate 100 to partially cover the respective surfaces.

[0148] The second external electrode 400 is connected to the negative electrode layer 150, on the second surface S2 of the laminate 100. The second external electrode 400 may extend onto the third surface S3, the fourth surface S4, the fifth surface S5, and the sixth surface S6 of the laminate 100 to partially cover the respective surfaces.

[0149] Meanwhile, in another embodiment, the first external electrode 300 and the second external electrode 400 may extend onto one of the fifth surface S5 and the sixth surface S6, to partially cover the corresponding surface.

[0150] The first external electrode 300 may include a base layer 310 and a plating layer 320, and the second external electrode 400 may include a base layer 410 and a plating layer 420

[0151] The base layer 310 of the first external electrode 300 may be electrically connected to the positive electrode layer 130, and the base layer 410 of the second external electrode 400 may be electrically connected to the negative electrode layer 150.

[0152] For example, the base layer 310 of the first external electrode 300 and the base layer 410 of the second external electrode 400 may be a fired electrode containing a conductive metal and glass, or a resin-based electrode containing a conductive metal and a resin.

[0153] The base layer 310 of the first external electrode 300 and the base layer 410 of the second external electrode 400 may be formed, for example, by applying a paste containing a conductive metal to the first surface S1 and the second surface S2 of the laminate 100, respectively, and may be formed by transferring a dry film made of a dried conductive paste to the laminate 100 and then firing the dry film, but the method for forming the base layers 310 and 410 is not limited thereto. Meanwhile, the conductive metal may include one or more of, for example, copper (Cu), nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), and alloys thereof, but is not limited thereto.

[0154] The plating layer 320 of the first external electrode 300 covers the base layer 310, and the plating layer 420 of the second external electrode 400 covers the base layer 410, such that the plating layers 320 and 420 may serve to enhance mounting characteristics of the external electrodes. The plating layers 320 and 420 may include one or more selected from the group consisting of copper (Cu), nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), and alloys thereof, but are not limited thereto. The plating layers may comprise one or more layers.

[0155] FIG. 7 is a schematic cross-sectional view for describing a structure formed by a positive electrode layer and a margin layer of the all-solid-state battery of FIG. 1. Below, the specific structure formed by the positive electrode layer and the margin layer will be described with reference to FIG. 7.

[0156] The positive electrode layer 130 and the margin layer 180 are disposed on the solid electrolyte layer 110, and the first end 137 of the positive electrode layer 130 (see FIGS. 3 and 6A) in the length direction (L-axis direction) is in contact with the margin layer 180.

[0157] The first positive electrode active material layer 135 is disposed on the solid electrolyte layer 110, the positive electrode current collector 133 is disposed on the first positive electrode active material layer 135, and the second positive electrode active material layer 136 is disposed on the positive electrode current collector 133. In addition, another solid electrolyte layer 110 is disposed on the second positive electrode active material layer 136.

[0158] The margin layer 180 may include a structure in which a first margin layer 181 and a second margin layer 182 are stacked.

[0159] The first margin layer 181 may be disposed on the solid electrolyte layer 110, and the first margin layer 181 may comprise a first interface C1 with the first positive electrode active material layer 135 and a second interface C2 with a positive electrode current collector 133.

[0160] The second margin layer 182 may be disposed on the first margin layer 181, and the second margin layer 182 may comprise a third interface C3 with the positive electrode current collector 133 and a fourth interface C4 with the second positive electrode active material layer 136.

[0161] The shape of the portion where the first positive electrode active material layer 135 is in contact with the margin layer 180, the shape of the portion where the positive electrode current collector 133 is in contact with the margin layer 180, and the shape of the portion where the second positive electrode active material layer 136 is in contact with the margin layer 180 may be different. This will be described below.

[0162] The first positive electrode active material layer 135 may comprise the first interface C1 with the margin layer 180. That is, the first positive electrode active material layer 135 is in contact with the first margin layer 181, and the boundary of which may be the first interface C1.

[0163] The first interface C1 may be a portion connecting a first point P1 and a second point P2.

[0164] The first point P1 may be a point where the first positive electrode active material layer 135, the first margin layer 181, and the solid electrolyte layer 110 meet. The second point P2 may be a point where the first positive electrode active material layer 135, the positive electrode current collector 133, and the first margin layer 181 meet.

[0165] In the length direction (L-axis direction), the second point P2 is closer to the second surface S2 of the laminate 100 than the first point P1. That is, the distance between the second surface S2 of the laminate 100 and the first point P1 may be greater than the distance between the second surface S2 of the laminate 100 and the second point P2. Therefore, the second point P2 may be the outermost point of the first positive electrode active material layer 135 in the length direction (L-axis direction). Since the first interface C1 connects the first point P1 and the second point P2, the first interface C1 may have a structure inclined with respect to the length direction (L-axis direction). For example, the first interface C1 may form an acute angle with the interface formed by the first positive electrode active material layer 135 and the solid electrolyte layer 110. Meanwhile, the shape of the first interface C1 may be a straight line, a curve, or an uneven surface, but the present embodiment is not limited thereto.

[0166] The positive electrode current collector 133 is disposed on the first positive electrode active material layer 135, and may comprise a second interface C2 and a third interface C3 with the margin layer 180.

[0167] The second interface C2 may be a portion connecting the second point P2 and a third point P3.

[0168] The third point P3 may be a point where the positive electrode current collector 133, the first margin layer 181, and the second margin layer 182 meet.

[0169] In the length direction (L-axis direction), the third point P3 is closer to the second surface S2 of the laminate 100 than the second point P2. That is, the distance between the second surface S2 of the laminate 100 and the second point P2 may be greater than the distance between the second surface S2 of the laminate 100 and the third point P3. Therefore, the third point P3 may be the outermost point of the positive electrode current collector 133 in the length direction (L-axis direction). Since the second interface C2 connects the second point P2 and the third point P3, the second interface C2 may have a structure inclined with respect to the length direction (L-axis direction). For example, the second interface C2 may form an acute angle with an imaginary extension surface of the first surface 133a of the positive electrode current collector 133. In another example, the second interface C2 may form an acute angle with the interface formed by the first positive electrode active material layer 135 and the solid electrolyte layer 110. Meanwhile, the shape of the second interface C2 may be a straight line, a curve, or an uneven surface, but the present embodiment is not limited thereto.

[0170] The third interface C3 may be a portion connecting the third point P3 and a fourth point P4.

[0171] The fourth point P4 may be a point where the positive electrode current collector 133, the second positive electrode active material layer 136, and the second margin layer 182 meet.

[0172] In the length direction (L-axis direction), the fourth point P4 is farther from the second surface S2 of the laminate 100 than the third point P3. That is, the distance between the second surface S2 of the laminate 100 and the fourth point P4 may be greater than the distance between the second surface S2 of the laminate 100 and the third point P3. In other words, the fourth point P4 may be disposed between the second point P2 and the third point P3 in the length direction (L-axis direction). Since the third interface C3 connects the third point P3 and the fourth point P4, the third interface C3 may have a structure inclined with respect to the length direction (L-axis direction). For example, the third interface C3 may form an acute angle with the second interface C2. Meanwhile, the shape of the third interface C3 may be a straight line, a curve, or an uneven surface, but the present embodiment is not limited thereto.

[0173] The second positive electrode active material layer 136 may comprise a fourth interface C4 with the margin layer 180. That is, the second positive electrode active material layer 136 is in contact with the second margin layer 182, and the boundary of which may be the fourth interface C4.

[0174] The fourth interface C4 may be a portion connecting the fourth point P4 and the fifth point P5.

[0175] The fifth point P5 may be a point where the second positive electrode active material layer 136, the second margin layer 182, and the solid electrolyte layer 110 meet.

[0176] In the length direction (L-axis direction), the fifth point P5 is closer to the second surface S2 of the laminate 100 than the fourth point P4. That is, the distance between the second surface S2 of the laminate 100 and the fourth point P4 may be greater than the distance between the second surface S2 of the laminate 100 and the fifth point P5. Therefore, the fifth point P5 may be the outermost point of the second positive electrode active material layer 136 in the length direction (L-axis direction). Since the fourth interface C4 connects the fourth point P4 and the fifth point P5, the fourth interface C4 may have a structure inclined with respect to the length direction (L-axis direction). For example, the fourth interface C4 may form an acute angle with the interface formed by the second positive electrode active material layer 136 and the solid electrolyte layer 110. Meanwhile, the shape of the fourth interface C4 may be a straight line, a curve, or an uneven surface, but the present embodiment is not limited thereto.

[0177] A width w1 of the first interface C1 and a width w2 of the second interface C2 may satisfy Formula 1.

[0178] [Formula 1]

[0179] 0.5 ≤ w1 / (w1 + w2) ≤ 0.85

[0180] If the value of w1 / (w1 + w2) is less than 0.5, the thickness of the first positive electrode active material layer 135 is thin and the positive electrode current collector 133 is thick, which may lead to a decrease in battery capacity, and if it is greater than 0.85, the length of the margin layer 180 becomes longer, increasing the risk of shorting.

[0181] Meanwhile, the width w1 of the first interface C1, the width w2 of the second interface, the width w3 of the third interface C3, and an gap d1 of the second point P2 and the fourth point P4 may satisfy Formula 2.

[0182] [Formula 2]

[0183] 0.15 ≤ (w3 + d1) / (w1 + w2) ≤ 0.5

[0184] If the value of (w3 + d1) / (w1 + w2) is less than 0.15, the positive electrode current collector 133 may be too thin and the electron transport may not be smooth, and if it is greater than 0.5, the positive electrode current collector 133 may be thick and the energy density of the all-solid-state-battery may decrease or the length of the margin layer 180 may become longer, thereby increasing the risk of shorting.

[0185] In addition, the width w3 of the third interface C3 and the gap d1 between the second point P2 and the fourth point P4 may satisfy Formula 3.

[0186] [Formula 3]

[0187] 0.5 ≤ w3 / d1 ≤ 1

[0188] If the value of w3 / d1 is less than 0.5, the positive electrode current collector 133 may be too thin and the electron transport may not be smooth, and if it is greater than 1, the positive electrode current collector 133 may be thick and the energy density of the all-solid-state-battery may decrease or the length of the margin layer 180 may become longer, thereby increasing the risk of shorting.

[0189] Here, the width w1 of the first interface C1 may refer to, based on an of the optical microscope photograph or scanning electron microscope (SEM) photograph of a cross-section taken along the length direction (L-axis direction)-thickness direction (T-axis direction) at a central portion of the laminate 100 in the width direction (W-axis direction), the shortest distance between two straight lines that pass through the first point P1 and the second point P2 shown in the above-described cross-sectional photograph and are respectively parallel to the thickness direction (T-axis direction).

[0190] The width w2 of the second interface C2 may be the shortest distance between two straight lines that pass through the second point P2 and the third point P3 shown in the above-described cross-sectional photograph and are respectively parallel to the thickness direction (T-axis direction).

[0191] The width w3 of the third interface C3 may be the shortest distance between the two straight lines that pass through the third point P3 and the fourth point P4 shown in the above-described cross-sectional photograph and are respectively parallel to the thickness direction (T-axis direction).

[0192] The gap d1 between the second point P2 and the fourth point P4 may be the shortest distance between the two straight lines that pass through the second point P2 and the fourth point P4 shown in the above-described cross-sectional photograph and are respectively parallel to the thickness direction (T-axis direction).

[0193] Meanwhile, the thickness t1 of the first positive electrode active material layer 135, the thickness t2 of the positive electrode current collector 133, and the thickness t3 of the second positive electrode active material layer 136 may satisfy Formula 4.

[0194] [Formula 4]

[0195] t1 ≥ t3 ≥ t2

[0196] Here, the thickness t1 of the first positive electrode active material layer 135 may refer to, based on an optical microscope photograph or scanning electron microscope (SEM) photograph of a cross-section taken along the length direction (L-axis direction)-thickness direction (T-axis direction) at a central portion of the laminate 100 in the width direction (W-axis direction), an arithmetic average value of the values measured at 10 equally spaced points on the first positive electrode active material layer shown in the above-described cross-sectional photograph. The thickness t2 of the positive electrode current collector 133 may refer to an arithmetic average value of the values measured at 10 equally spaced points on the positive electrode current collector shown in the above-described cross-sectional photograph. The thickness t3 of the second positive electrode active material layer may refer to an arithmetic average value of the values measured at 10 equally spaced points on the second positive electrode active material layer shown in the above-described cross-sectional photograph. However, the above-described measurement point may be a portion excluding the portion where the first positive electrode active material layer, the positive electrode current collector, and the second positive electrode active material layer form an interface with the margin layer, respectively.

[0197] Meanwhile, since the structure formed by the negative electrode layer 150 and the margin layer 180 adjacent to the negative electrode layer 150 corresponds to the structure formed by the positive electrode layer 130 and the margin layer 180 described above, redundant descriptions thereof will be omitted.

[0198] FIG. 8 is a schematic diagram for describing a method for forming a positive electrode layer and a margin layer of an all-solid-state battery according to an embodiment.

[0199] Referring to FIG. 8, the first margin layer 181 is formed on the solid electrolyte layer 110. The first margin layer 181 may be formed in various ways. For example, the first margin layer 181 may be formed by stacking or impregnating the above-described ceramic material on the solid electrolyte layer 110. In another example, a slurry containing the above-described ceramic material may be applied to the solid electrolyte layer 110 to form the first margin layer 181, or a sheet made of the above-described ceramic material may be attached to the solid electrolyte layer 110 to form the first margin layer 181.

[0200] Next, the first positive electrode active material layer 135 is formed to cover the end of the first margin layer 181 and the solid electrolyte layer 110. The first positive electrode active material layer 135 may be formed by printing a positive electrode active material on the surface of the solid electrolyte layer 110, but the method for forming the first positive electrode active material layer is not limited thereto.

[0201] Next, the positive electrode current collector 133 is formed to cover a portion of the first margin layer 181 and the first positive electrode active material layer 135. The positive electrode current collector 133 may be formed by printing a material for positive electrode current collector on the surface of the first positive electrode active material layer 135, but the method for forming the positive electrode current collector is not limited thereto.

[0202] Next, the second margin layer 182 is formed to cover the end of the positive electrode current collector 133. The method for forming the second margin layer 182 may include a variety of methods, similar to the method for forming the first margin layer 181.

[0203] Next, the second positive electrode active material layer 136 is formed to cover the end of the second margin layer 182 and the positive electrode current collector 133. The method for forming the second positive electrode active material layer 136 may include a variety of methods, similar to the method for forming the first positive electrode active material layer 135.

[0204] By adjusting the structure of the interfaces formed between the first positive electrode active material layer 135, the first margin layer 181, the positive electrode current collector 133, the second margin layer 182, and the second positive electrode active material layer 136 during the above process, the positive electrode layer 130 and the margin layer 180 having the structure described above may be formed.

[0205] Meanwhile, the method for forming the negative electrode layer 150 and the margin layer 180 in contact with the negative electrode layer 150 corresponds to the method for forming the positive electrode layer 130 and the margin layer 180 described above, except for the material for the negative electrode layer, and therefore, redundant descriptions thereof will be omitted.

[0206] FIG. 9 is a schematic cross-sectional view for describing a structure formed by a positive electrode layer and a margin layer of an all-solid-state battery according to Comparative Example.

[0207] Referring to FIG. 9, the positive electrode layer 230 and the margin layer 280 are disposed on the solid electrolyte layer 210, and a portion of the outer surface of the positive electrode layer 230 is in contact with the margin layer 280.

[0208] A first positive electrode active material layer 235 is disposed on the solid electrolyte layer 210, a positive electrode current collector 233 is disposed on the first positive electrode active material layer 235, and a second positive electrode active material layer 236 is disposed on the positive electrode current collector 233. However, the end of the positive electrode layer 230 is in contact with only the solid electrolyte layer 210 and does not form an interface with the margin layer 280. That is, the first positive electrode active material layer 235 and the positive electrode current collector 233 do not contact the margin layer 280, and only a portion of the outer surface of the second positive electrode active material layer 236 forms an interface with the margin layer 280.

[0209] The positive electrode layer with such a structure is easy to deform during the formation of the laminate and cause a short circuit with the negative electrode layer.

[0210] Hereinafter, specific examples of the present disclosure are presented. However, the examples described below are only for illustrating or describing the disclosure in detail, and should not limit the scope of the disclosure.

[0211] [Preparing Example: Manufacture of all-solid-state battery]

[0212] (Example)

[0213] A positive electrode sheet was prepared by forming, in order, a first margin layer, a first positive electrode active material layer, a positive electrode current collector, a second margin layer, and a second positive electrode active material layer on a solid electrolyte layer.

[0214] A negative electrode sheet was prepared by forming, in order, a first margin layer, a first negative electrode active material layer, a negative electrode current collector, a second margin layer, and a second negative electrode active material layer on a solid electrolyte layer.

[0215] A green chip was formed by alternately stacking the positive electrode sheet and negative electrode sheet.

[0216] The green chip was cut to form a laminate.

[0217] The laminate was calcined at a temperature of 300 °C or more and 400 °C or less in an air or nitrogen atmosphere.

[0218] After the calcination, the laminate was sintered at a temperature of 400 °C or more and 550 °C or less in an air or nitrogen atmosphere.

[0219] A conductive paste for an external electrode was applied onto a surface of the sintered laminate, and then external electrodes were formed by maintaining the laminate in a curing oven sequentially at 50 °C, 80 °C, and 200 °C for 30 minutes for each temperature and then cooling the laminate. In this way, an all-solid-state battery was manufactured.

[0220] In the manufactured all-solid-state battery, a width w1 of a first interface C1 was 35 um, a sum of the width w1 of the first interface C1 and a width w2 of a second interface C2 was 60 um, a width w3 of a third interface C3 was 10 um, a width w4 of a fourth interface C4 was 50 um, a gap d1 between a second point P2 and a fourth point P4 was 15 um, a thickness t1 of a first positive electrode active material layer was 70 um, a thickness t2 of a positive electrode current collector was 10 um, and a thickness t3 of a second positive electrode active material layer was 70 um. (see FIG. 7)

[0221] (Comparative Example 1)

[0222] The manufactured all-solid-state battery according to Comparative Example 1 was the same as Example except that a width w1 of a first interface C1 was 70 um, a sum of the width w1 of the first interface C1 and a width w2 of a second interface C2 was 150 um, a width w3 of a third interface C3 was 15 um, a width w4 of a fourth interface C4 was 70 um, a gap d1 between a second point P2 and a fourth point P4 was 65 um.

[0223] (Comparative Example 2)

[0224] A positive electrode sheet was manufactured by forming, in order, a first positive electrode active material layer, a positive electrode current collector, a second positive electrode active material layer, and a margin layer on a solid electrolyte layer.

[0225] A negative electrode sheet was manufactured by forming, in order, a first negative electrode active material layer, a negative electrode current collector, a second negative electrode active material layer, and a margin layer on a solid electrolyte layer.

[0226] A green chip was formed by alternately stacking the positive electrode sheet and negative electrode sheet.

[0227] The green chip was cut to form a laminate.

[0228] The laminate was calcined at a temperature of 300 °C or more and 400 °C or less in an air or nitrogen atmosphere.

[0229] After the calcination, the laminate was sintered at a temperature of 400 °C or more and 550 °C or less in an air or nitrogen atmosphere.

[0230] A conductive paste for an external electrode was applied onto a surface of the sintered laminate, and then external electrodes were formed by maintaining the laminate in a curing oven sequentially at 50 °C, 80 °C, and 200 °C for 30 minutes for each temperature and then cooling the laminate. In this way, an all-solid-state battery was manufactured.

[0231] The manufactured all-solid-state battery according to Comparative Example 2 was the same as Example except that a gap d2 between both end points of an interface formed by a second positive electrode active material layer and a margin layer was 150 um, a gap d3 between two end points of an interface formed by a positive electrode current collector and a solid electrolyte was 50 um, and a gap d4 between both end points of an interface formed by the second positive electrode active material layer and the solid electrolyte was 25 um. (see FIG. 9)

[0232] [Experimental Example: Performance of all-solid-state battery]

[0233] Thirty (30) pieces of all-solid-state batteries according to Example and Comparative Examples 1 and 2 were manufactured, respectively, and subjected to repeated charge / discharge cycles tests. The results are summarized in Table 1.

[0234] w1 / (w1 + w2)(w3 + d1) / (w1 + w2)w3 / d1Whether charge / discharge are performed normallyExample0.580.420.67NormalComparative Example 10.470.530.23Not normalComparative Example 2---Not normal

[0235] Referring to Table 1, the all-solid-state batteries manufactured according to Example were charged and discharged normally. In other words, it can be seen that even if the positive electrode layer and / or negative electrode layer deformed during the sintering process of the all-solid-state battery, no micro-short circuits occurred. On the other hand, the all-solid-state batteries manufactured according to Comparative Examples 1 and 2 were not sufficiently charged and discharged. This is because the positive electrode layer and / or negative electrode layer deformed and came into close proximity or contact with each other, causing micro-short circuits.

[0236] While the embodiments of the present disclosure have been described above, the present disclosure is not limited thereto, and various modifications can be made and carried out within the scope of the claims, the detailed description of the present disclosure, and the accompanying drawings, and also fall within the scope of the present disclosure.

[0237] <Description of symbols>

[0238] 1000: All-solid-state battery

[0239] 100: Laminate

[0240] 110: Solid electrolyte layer

[0241] 130: Positive electrode layer

[0242] 131: Positive electrode body

[0243] 132: Positive electrode margin portion

[0244] 133: Positive electrode current collector

[0245] 135: First positive electrode material layer

[0246] 136: Second positive electrode material layer

[0247] 150: Negative electrode layer

[0248] 151: Negative electrode body

[0249] 152: Negative electrode margin portion

[0250] 153: Negative electrode current collector

[0251] 155: First negative electrode active material layer

[0252] 156: Second negative electrode active material layer

[0253] 160: Upper protective layer

[0254] 170: Lower protective layer

[0255] 180: Margin layer

[0256] 181: First margin layer

[0257] 182: Second margin layer

[0258] 300: First external electrode

[0259] 310: Base layer

[0260] 320: Plating layer

[0261] 400: Second external electrode

[0262] 410: Base layer

[0263] 420: Plating layer

[0264] C1: First interface

[0265] C2: Second interface

[0266] C3: Third interface

[0267] C4: Fourth interface

[0268] P1: First point

[0269] P2: Second point

[0270] P3: Third point

[0271] P4: Fourth point

[0272] P5: Fifth point

[0273] E1, E2: Imaginary extension line

[0274] θ1, θ2: Outer angle

Claims

1.An all-solid-state battery, comprising:a laminate including a solid electrolyte layer, an electrode layer stacked in a first direction with the solid electrolyte layer interposed therebetween, and a margin layer in contact with the electrode layer in a second direction intersecting the first direction; andan external electrode disposed outside of the laminate and electrically connected to the electrode layer,wherein the electrode layer includes: a current collector having a first surface and a second surface opposing the first surface, a first active material layer disposed on the first surface of the current collector, and a second active material layer disposed on the second surface of the current collector, andwherein outermost points in the second direction where the first active material layer, the current collector, and the second active material layer are in contact with the margin layer are, in a listed order, farther from the external electrode.2.The all-solid-state battery of claim 1, wherein:the first active material layer comprises a first interface with the margin layer.3.The all-solid-state battery of claim 2, wherein:the first interface comprises an acute angle with the solid electrolyte layer in contact with the first active material layer.4.The all-solid-state battery of claim 3, wherein:the first interface connects a first point where the first active material layer, the margin layer, and the solid electrolyte layer meet, and a second point where the first active material layer, the current collector, and the margin layer meet.5.The all-solid-state battery of claim 4, wherein:the current collector comprises a second interface with the margin layer.6.The all-solid-state battery of claim 5, wherein:the second interface comprises an acute angle with the solid electrolyte layer in contact with the first active material layer.7.The all-solid-state battery of claim 5, wherein:the second interface connects the second point and a third point which is an outermost point, among the outermost points in the second direction, where the current collector is in contact with the margin layer.8.The all-solid-state battery of claim 7, wherein:the current collector further comprises a third interface with the margin layer, andthe third interface comprises an acute angle with the second interface.9.The all-solid-state battery of claim 8, wherein:the third interface connects the third point and a fourth point where the second active material layer, the current collector, and the margin layer meet.10.The all-solid-state battery of claim 9, wherein:the second active material layer comprises a fourth interface with the margin layer.11.The all-solid-state battery of claim 10, wherein:the fourth interface comprises an acute angle with the solid electrolyte layer in contact with the first active material layer.12.The all-solid-state battery of claim 10, wherein:the fourth interface connects the fourth point and a fifth point where the second active material layer, the solid electrolyte layer, and the margin layer meet.13.The all-solid-state battery of claim 1, wherein:the first active material layer comprises a first interface with the margin layer,the current collector comprises a second interface with the margin layer and a third interface comprising an acute angle with the second interface, respectively,the second active material layer comprises a fourth interface with the margin layer, andsatisfying Formula 1:[Formula 1]0.5 ≤ w1 / (w1 + w2) ≤ 0.85where,w1: width of the first interfacew2: width of the second interface.14.The all-solid-state battery of claim 13, wherein:the second interface connects a second point where the first active material layer, the current collector, and the margin layer meet, and a third point which is an outermost point, among the outermost points in the second direction, where the current collector is in contact with the margin layer,the third interface connects the third point and a fourth point where the second active material layer, the current collector, and the margin layer meet, andfurther satisfying Formula 2:[Formula 2]0.15 ≤ (w3 + d1) / (w1 + w2) ≤ 0.5where,w3: width of the third interfaced1: gap between the second and fourth points.15.The all-solid-state battery of claim 14, further satisfying Formula 3:[Formula 3]0.5 ≤ w3 / d1 ≤ 116.The all-solid-state battery of claim 1, wherein:the margin layer includesa first margin layer in contact with the first active material layer and the current collector, anda second margin layer in contact with the first margin layer, the current collector, and the second active material layer.17.The all-solid-state battery of claim 1, wherein:an ionic conductivity of solid electrolyte included in the solid electrolyte layer is 10-6S / cm or more.18.The all-solid-state battery of claim 1, wherein:the margin layer includes an insulating material.19.The all-solid-state battery of claim 18, wherein:an ionic conductivity of the insulating material is 10-6S / cm or less.20.An electrode for an all-solid-state battery, comprising:an electrode layer comprising:a current collector having a first surface and a second surface opposing the first surface in a thickness direction,a first active material layer disposed on the first surface, anda second active material layer disposed on the second surface; anda margin portion disposed between a first of a pair of longitudinally opposing edges of the electrode layer and a first external electrode of the all-solid-state battery,wherein a second of the pair of longitudinally opposing edges of the electrode layer contacts a second external electrode of the all-solid-state battery, andwherein a distance, in the longitudinal direction, between the first external electrode and points at which the first active material layer, the current collector, and the second active material layer contact the margin portion is sequentially greater.

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