All-solid-state battery and method for manufacturing same

Abstract

The present invention relates to a positive electrode mixture layer for an all-solid-state battery. More specifically, the positive electrode mixture layer includes: a positive electrode current collector; a positive electrode active material layer on the positive electrode current collector; and a first solid electrolyte layer on the positive electrode active material layer, wherein the positive electrode current collector includes a main body and a positive electrode tab protruding in one direction from the main body, and the first solid electrolyte layer may include a first region adjacent to the positive electrode tab and a second region excluding the first region. The first region includes first solid electrolyte particles, and the second region includes second solid electrolyte particles, wherein the average particle size of the first solid electrolyte particles is larger than the average particle size of the second solid electrolyte particles, and the ratio of the area of the first region to the area of the second region may be 2:8 to 5:5.

Description

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

[0001] This is about all-solid-state batteries.

[0002] Recently, driven by industrial demands, the development of batteries with high energy density and stability is actively underway. For example, lithium-ion batteries are being commercialized not only in the fields of information and communication devices but also in the automotive sector. In the automotive sector, safety is considered particularly important because it is directly related to human life.

[0003] Recently, all-solid-state batteries in which liquid electrolytes are replaced with solid electrolytes have been proposed. By not using flammable organic dispersion media, all-solid-state batteries can significantly reduce the likelihood of fire or explosion in the event of a short circuit. Therefore, these all-solid-state batteries can offer significantly higher safety compared to lithium-ion batteries that use liquid electrolytes.

[0004] The problem that the present invention aims to solve is to improve the ion conductivity, rate characteristics, and output characteristics of an all-solid-state battery by controlling the average particle size of solid electrolyte particles within the solid electrolyte layer.

[0005] A positive electrode composite layer according to the concept of the present invention comprises a positive electrode current collector; a positive electrode active material layer on the positive electrode current collector; and a first solid electrolyte layer on the positive electrode active material layer, wherein the positive electrode current collector comprises a main body portion and a positive electrode tab protruding in one direction from the main body portion, and the first solid electrolyte layer may comprise a first region adjacent to the positive electrode tab and a second region excluding the first region. The first region comprises a first solid electrolyte particle, and the second region comprises a second solid electrolyte particle, wherein the average particle size of the first solid electrolyte particle is larger than the average particle size of the second solid electrolyte particle, and the ratio of the area of ​​the first region to the area of ​​the second region may be 2:8 to 5:5.

[0006] A solid-state battery according to another concept of the present invention comprises a negative electrode composite layer, said negative electrode composite layer comprises a negative electrode current collector and a negative electrode coating layer on said negative electrode current collector; and said positive electrode composite layer.

[0007] A method for manufacturing an all-solid-state battery according to another concept of the present invention may include forming a positive electrode by forming a positive active material layer on a positive current collector; forming a negative electrode by forming a negative coating layer on a negative current collector; and forming a solid electrolyte layer. Forming the solid electrolyte layer may include forming a first composition comprising a first solid electrolyte; forming a second composition comprising a second solid electrolyte; coating the first composition in a first direction to form a first region having a first width; and coating the second composition in the first direction to form a second region having a second width parallel to the first region, wherein the positive current collector includes a positive tab protruding in a second direction, and the solid electrolyte layer is arranged such that the first region is adjacent to the positive tab in the second direction, and the average particle size of the first solid electrolyte may be larger than the average particle size of the second solid electrolyte.

[0008] According to one aspect, an all-solid-state battery with high power and high rate characteristics can be provided. According to another aspect, a method for manufacturing an all-solid-state battery with high power and high rate characteristics can be provided. In addition, the mass producibility of the all-solid-state battery can be improved.

[0009] FIG. 1 is a schematic cross-sectional view of an all-solid-state battery unit cell according to an embodiment of the present invention.

[0010] FIG. 2 is a plan view of an anode composite layer according to an embodiment of the present invention.

[0011] Figure 3 is a cross-sectional view along the line A-A' of Figure 2.

[0012] Figure 4 is an enlarged view of the M region of Figure 3.

[0013] FIG. 5 is a cross-sectional view of an anode composite layer according to one embodiment.

[0014] FIGS. 6 and FIGS. 7 are cross-sectional views of an all-solid-state battery unit cell according to one embodiment.

[0015] FIGS. 8 to 10 are cross-sectional views of an all-solid-state battery unit cell according to one embodiment.

[0016] FIGS. 11 to 17 illustrate a method for manufacturing an all-solid-state battery according to an embodiment of the present invention.

[0017]

[0018] In order to fully understand the structure and effects of the present invention, preferred embodiments of the present invention are described with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and various modifications can be made. The description of these embodiments is provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention.

[0019] In this specification, when a component is described as being on another component, it means that it may be formed directly on the other component or that a third component may be interposed between them. Additionally, in the drawings, the thicknesses of the components are exaggerated for the effective description of the technical content. Throughout the specification, parts indicated by the same reference numeral represent the same components.

[0020] The embodiments described herein will be described with reference to cross-sectional and / or plan views, which are exemplary illustrations of the invention. In the drawings, the thicknesses of films and regions are exaggerated for effective description of the technical content. Accordingly, the regions illustrated in the drawings are schematic in nature, and the shapes of the regions illustrated in the drawings are intended to illustrate specific forms of regions of the device and are not intended to limit the scope of the invention. Although terms such as first, second, third, etc., have been used to describe various components in the various embodiments of this specification, these components should not be limited by such terms. These terms are used merely to distinguish one component from another. The embodiments described and illustrated herein also include their complementary embodiments.

[0021] The terms used herein are for describing the embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used herein, 'comprises' and / or 'comprising' do not exclude the presence or addition of one or more other components to the mentioned components.

[0022] In this specification, "combination of these" may mean a mixture of components, a laminate, a composite, a copolymer, an alloy, a blend, and a reaction product, etc.

[0023] Unless otherwise defined in this specification, the particle size may be the average particle size. Additionally, the particle size refers to the average particle size (D50), which means the diameter of the particle whose cumulative volume in the particle size distribution is 50% by volume. The average particle size (D50) may be measured by methods widely known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope (TEM) image or a scanning electron microscope (SEM) image. Alternatively, the average particle size (D50) value may be obtained by measuring using a measuring device utilizing dynamic light-scattering, performing data analysis to count the number of particles for each particle size range, and then calculating from this. Alternatively, it may be measured using a laser diffraction method. When measuring by laser diffraction, more specifically, after dispersing the particles to be measured in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasound of about 28 kHz at an output of 60 W, and then the average particle size (D50) at 50% of the particle size distribution in the measuring device can be calculated.

[0024] In this specification, each of the phrases such as “A or B”, “at least one of A and B”, “at least one of A or B”, “A, B or C”, “at least one of A, B and C”, and “at least one of A, B, or C” may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0025]

[0026] All-solid-state battery

[0027] An all-solid-state battery according to an embodiment of the present invention may include a unit cell (CEL). A unit cell may refer to a minimum unit for operating a battery. A unit cell (CEL) may include a minimum component of an all-solid-state battery. Referring to FIG. 1, a unit cell (CEL) may include a positive electrode (CTH), a negative electrode (ANO), and a solid electrolyte layer (SEL) between the positive electrode (CTH) and the negative electrode (ANO). In some cases, the unit cell (CEL) may further include an additional functional layer, such as an adhesion-enhancing layer, disposed between the positive electrode (CTH) and the solid electrolyte layer (SEL) or between the negative electrode (ANO) and the solid electrolyte layer (SEL). An all-solid-state battery may include a plurality of unit cells (CEL).

[0028] A unit cell (CEL) may include an anode composite layer and a cathode composite layer. The unit cell (CEL) may be a stack of an anode composite layer and a cathode composite layer. The anode composite layer may include an anode current collector, an anode active material layer, and a first solid electrolyte layer. The cathode composite layer may include a cathode current collector and a cathode coating layer. In some cases, the cathode composite layer may further include a second solid electrolyte layer. Hereinafter, an all-solid-state battery according to an embodiment of the present invention will be described with a focus on the anode composite layer.

[0029] Cathode composite layer (CSH)

[0030] FIG. 2 is a plan view of an anode composite layer (CSH) according to an embodiment of the present invention. FIG. 3 is a cross-sectional view along line A-A' of FIG. 2. FIG. 4 is an enlarged view of region M of FIG. 3. The anode composite layer (CSH) according to an embodiment of the present invention may include an anode current collector (COL1) and an anode active material layer (CML) disposed on the anode current collector (COL1). The anode composite layer (CSH) may include a first solid electrolyte layer (SEL1) on the anode active material layer (CML). The anode active material layer (CML) may include an anode active material and a solid electrolyte.

[0031] The positive current collector (COL1) can provide a reference surface on which the positive active material layer (CML) is placed. The positive current collector (COL1) may include, for example, a plate or foil comprising 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.

[0032] To increase the bonding strength between the positive current collector (COL1) and the positive active material layer (CML), a carbon-containing layer with a thickness of 0.1 μm to 4 μm, or 1 μm to 3 μm, may be further disposed between the positive current collector (COL1) and the positive active material layer (CML). As an example, the carbon-containing layer may contain a relatively large amount of binder. The carbon-containing layer can improve the adhesion strength between the positive current collector (COL1) and the positive active material layer (CML) while simultaneously improving the conductivity of the positive (CTH).

[0033] The positive active material of the positive active material layer (CML) may include a material capable of reversibly absorbing and desorbing lithium ions. The positive active material may include a plurality of particles. The positive active material may include, for example, 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, but is not necessarily limited to these. Each positive active material may be a single material or a mixture of two or more materials.

[0034] Lithium transition metal oxides are, for example, Lia A 1-b B b D2(0.90≤a≤1, 0≤b≤0.5), Li a HAVE BEEN 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 Mr 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 Mr 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 b HAVE BEEN c G d O2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1), Li a Ni b Co c Mr 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), Lia 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-f It is a compound represented by any one of Fe2(PO4)3 (0≤f≤2) or LiFePO4. In such compounds, the uppercase “A” is Ni, Co, Mn, or a combination thereof; the uppercase “B” is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; the uppercase “D” is O, F, S, P, or a combination thereof; the uppercase “E” is Co, Mn, or a combination thereof; the uppercase “F” is F, S, P, or a combination thereof; the uppercase “G” is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; the uppercase “Q” is Ti, Mo, Mn, or a combination thereof; the uppercase “I” is Cr, V, Fe, Sc, Y, or a combination thereof; and the uppercase “J” is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0035] The positive electrode 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 and metal atomic layers are alternately and regularly arranged in a specific direction, thereby forming a two-dimensional plane for each atomic layer. The "cubic rock salt type structure" represents a sodium chloride (NaCl type) structure, which is a type of crystal structure; specifically, it exhibits a structure in which face-centered cubic lattices (fcc) formed by cations and anions, respectively, are offset from each other by half the ridge of the unit lattice. Lithium transition metal oxides having such a layered rock salt type structure are, for example, LiNi x Co y Al z O2(NCA) or LiNi x Co y Mn z O2(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, 단위셀의 에너지 밀도가 커지고 열안정성이 향상될 수 있다.

[0036] The aforementioned compound contained 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 aforementioned compound and the compound to which the coating layer is added. Meanwhile, the coating layer added to the surface of the positive electrode active material may include, for example, oxides, hydroxides, oxyhydroxides, oxycarbonates, or hydroxycarbonates of the following coating elements. The compounds forming this coating layer are 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 is, for example, spray coating or immersion.

[0037] When the cathode active material is a ternary lithium transition metal oxide, such as NCA or NCM, containing nickel (Ni), it is possible to increase the capacity density of the unit cell and reduce the metal leaching of the cathode active material in the charged state. Consequently, the cycle characteristics of the unit cell in the charged state are improved. Meanwhile, "cycle characteristics" refers to the degree of degradation of the unit cell due to charging and discharging; unit cells with high cycle characteristics experience less degradation due to charging and discharging, while unit cells with low cycle characteristics may experience greater degradation.

[0038] The positive active material may have particle shapes such as spheres or ellipsoids. The particle size and content of the positive active material are not particularly limited. For example, the average particle size of the positive active material analyzed by scanning electron microscope (SEM) images may be 200 nm to 25 µm.

[0039] The solid electrolyte of the positive active material layer (CML) may have a particle shape. The solid electrolyte may be dispersed among the positive active materials (CAC). The solid electrolyte may include a sulfide-based solid electrolyte with excellent lithium ion conductivity characteristics. Sulfide-based solid electrolytes are, for example, Li2S-P2S5, Li2S-P2S5-LiX (where 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, uppercase “Z” is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are positive numbers, uppercase “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), or Li 7-x PS 6-x I x It may include at least one of (0≤x≤2).

[0040] Sulfide-based solid electrolytes are, for example, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), or Li 7-x PS 6-x I xIt may be an argyrodite-type compound containing at least one of (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound containing at least one of Li6PS5Cl, Li6PS5Br, or Li6PS5I.

[0041] Alternatively, sulfide-based solid electrolytes are Li 7-a-c M a PS 6-c X c It may be an argyrodite-type compound containing (0≤a≤2, 0≤c≤2). Here, X may be F, Br, Cl, I, or a combination thereof. M can be scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof. there is.

[0042] The density of the azyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. By having a density of 1.5 g / cc or higher for the azyrodite-type solid electrolyte, the internal resistance of the all-solid-state battery is reduced, and defects such as penetration and short circuit of the solid electrolyte film due to lithium dendrite formation can be prevented. The elastic modulus of the solid electrolyte may be, for example, 15 GPa to 35 GPa.

[0043] The solid electrolyte in the positive active material layer (CML) may have a smaller average particle size compared to the solid electrolyte in the solid electrolyte layer described later. For example, the average particle size of the solid electrolyte in the positive active material layer (CML) may be 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, or 20% or less of the average particle size of the solid electrolyte in the solid electrolyte layer. Meanwhile, the average particle size may be the median diameter measured using a laser particle size distribution meter.

[0044] The positive active material layer (CML) may further include a binder. The binder may bind the positive active material, solid electrolyte, and conductive material within the positive active material layer (CML) together. The binder may include a material to improve the bonding strength between the positive active material layer (CML) and the positive current collector (COL1). The binder (BID) may include, for example, at least one of polyvinylidene fluoride, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, or polymethyl methacrylate.

[0045] The positive active material layer (CML) may further include a conductive material. The conductive material may provide conductivity without causing chemical changes in the unit cell, thereby increasing the conductivity of the positive active material (CAC) and the solid electrolyte (SEP). The conductive material may include a carbon-based material. The conductive material may include, for example, at least one of graphite, carbon black, acetylene black, carbon nanofibers, or carbon nanotubes.

[0046] In one embodiment, the content of the positive active material with respect to the total weight of the positive active material layer (CML) may be 10% to 99% by weight, 30% to 80% by weight, 40% to 70% by weight, 40% to 50% by weight, 60% to 90% by weight, or 70% to 90% by weight.

[0047] In one embodiment, the content of the solid electrolyte in the positive active material layer (CML) may be 10% to 70% by weight, 10% to 60% by weight, 5% to 30% by weight, 5% to 25% by weight, or 10% to 40% by weight of the total weight of the positive active material layer (CML).

[0048] The positive active material layer (CML) may further include additives such as fillers, coating agents, dispersants, and ion conductivity aids in addition to the aforementioned positive active material (CAC), solid electrolyte (SEP), conductive material, and binder.

[0049] Hereinafter, an anode composite layer according to an embodiment of the present invention will be described in more detail with reference to the drawings. Referring to FIG. 2, the anode current collector (COL1) may include a main body portion (MBD) and an anode tab (CTB). The main body portion (MBD) may provide an area where an anode active material layer (CML) is disposed. The anode tab (CTB) may refer to an unprotected area protruding in one direction from the main body portion (MBD). That is, the anode active material layer (CML) may be provided on the main body portion (MBD) but may not be provided on the anode tab (CTB).

[0050] As shown in FIG. 2, when describing an embodiment in which the positive tab (CTB) protrudes in a second direction, the main body (MBD) may include a first end (ED1) and a second end (ED2) facing each other in a second direction (D2). Each of the first end (ED1) and the second end (ED2) may represent one end of the main body (MBD). The first end (ED1) may cross the boundary between the positive tab (CTB) and the main body (MBD). That is, the positive current collector (COL1) may be divided into the main body (MBD) and the positive tab (CTB) based on the first end (ED1).

[0051] The main body may include a tab adjacent portion. The tab adjacent portion may be an area extending from the first end toward the second end. For example, the tab adjacent portion may be an area extending from the first end toward the second end and occupying 20% ​​to 30% of the total area of ​​the main body.

[0052] The positive tab (CTB) is electrically connected to the lead tab and can be connected to the outside of the unit cell. The positive tab (CTB) can transmit the current generated at the positive electrode to an external circuit. The positive tab (CTB) can serve to provide a stable flow of current between the inside and outside of the unit cell. However, a problem may arise where the local current density increases in the region adjacent to the positive tab (CTB) within the positive electrode composite layer (CSH). This imbalance in current density may cause electrical and chemical reactions to be biased in the region surrounding the positive tab (CTB), leading to performance degradation phenomena such as overheating or excessive lithium consumption in that area.

[0053] This degrades the structural stability of the positive composite layer (CSH) and can cause short circuits. Furthermore, this problem can be exacerbated if the electrode loading amount or thickness is increased to improve the capacity of the all-solid-state battery.

[0054] To solve these problems, an embodiment of the present invention aims to improve the uniformity of current density through the structural design of the anode composite layer (CSH). Referring to FIG. 3, the anode composite layer (CSH) according to an embodiment of the present invention may include an anode current collector (COL1), an anode active material layer (CML) on the anode current collector (COL1), and a first solid electrolyte layer (SEL1) on the anode active material layer (CML).

[0055] The first solid electrolyte layer (SEL1) may include a first region (AR1) and a second region (AR2). The first region (AR1) is defined as a region adjacent to the anode tab (CTB), and the second region (AR2) may be a region excluding the first region (AR1). In this case, each of the first region (AR1) and the second region (AR2) may include solid electrolyte particles.

[0056] In one embodiment, as shown in FIG. 3, the area of ​​the first solid electrolyte layer (SEL1) and the area of ​​the positive active material layer (CML) may be substantially the same. In this case, the area may be defined based on a plane (D1D2, see FIG. 2) formed in the first direction and the second direction.

[0057] The first region (AR1) may be located on the tap adjacent region (ADJ). The area of ​​the first region (AR1) may coincide with the area of ​​the tap adjacent region (ADJ), but may differ. For example, part or all of the first region (AR1) may be included within a virtual cross-sectional area parallel to the tap adjacent region (ADJ). In one embodiment, the first region (AR1) may be vertically overlapped with the tap adjacent region (ADJ).

[0058] The areas of the first region (AR1) and the second region (AR2) in the first solid electrolyte layer (SEL1) may differ from each other. The areas of the first region (AR1) and the second region (AR2) may each be defined as areas based on a plane (D1D2, see FIG. 2) formed in the first direction and the second direction.

[0059] Referring to FIG. 4, the first region (AR1) may include first solid electrolyte particles (SEP1), and the second region (AR2) may include second solid electrolyte particles (SEP2). Each of the first solid electrolyte particles (SEP1) and the second solid electrolyte particles (SEP2) may include a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics. Each of the first solid electrolyte particles (SEP1) and the second solid electrolyte particles (SEP2) may be identical to or different from any one of the materials included in the solid electrolyte within the aforementioned positive electrode active material layer (CML).

[0060] Each of the first and second solid electrolyte particles (SEP1, SEP2) may be amorphous, crystalline, or a mixture thereof. Additionally, the solid electrolyte may include sulfur (S), phosphorus (P), and lithium (Li) as constituent elements, for example, among the sulfide-based solid electrolyte materials described above. For example, the solid electrolyte may be a material containing Li2S-P2S5. When using a sulfide-based solid electrolyte material containing Li2S-P2S5 to form the solid electrolyte, the molar ratio of Li2S and P2S5 is, for example, in the range of Li2S : P2S5 = 50 : 50 to 90 : 10.

[0061] In one embodiment, the first and second solid electrolyte particles (SEP1, SEP2) each have Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), or Li 7-x PS 6-x I xIt may include an argyrodite-type compound comprising at least one of (0≤x≤2). The solid electrolyte may include an argyrodite-type compound comprising at least one of Li6PS5Cl, Li6PS5Br, or Li6PS5I.

[0062] In another embodiment, the first and second solid electrolyte particles (SEP1, SEP2) each have Li 7-a-c M a PS 6-c X c It may include an argyrodite-type sulfide-based solid electrolyte represented by (0≤a≤2, 0≤c≤2). In this case, X may include F, Br, Cl, or a combination thereof, and M is scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), It may be antimony (Sb), bismuth (Bi), or a combination thereof.

[0063] The density of the azyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. Since the azyrodite-type solid electrolyte has a density of 1.5 g / cc or higher, the internal resistance of the all-solid-state battery is reduced, and defects such as penetration and short circuit of the solid electrolyte film due to lithium dendrite formation can be prevented. The elastic modulus of the solid electrolyte is, for example, 15 GPa to 35 GPa.

[0064] Each of the first solid electrolyte particle (SEP1) and the second solid electrolyte particle (SEP2) may have a particle shape such as a sphere or an ellipsoid. The average particle size (D50) of the first solid electrolyte particle (SEP) may be larger than the average particle size of the second solid electrolyte particle (SEP2). The ratio of the average particle size of the first solid electrolyte particle to the average particle size of the second solid electrolyte particle may be 2.0 to 5.0.

[0065] In one embodiment, the average particle size of the first solid electrolyte particle (SEP1) may be 2 μm to 5 μm. In one embodiment, the average particle size of the second solid electrolyte particle (SEP2) may be 0.5 μm to 2 μm.

[0066] By increasing the size of the first solid electrolyte particle (SEP1) in the first region (AR1), the resistance of the first region (AR1) can be intentionally increased. By increasing the resistance of the first region (AR1), the increase in local current density in the region adjacent to the anode tab (CTB) can be suppressed. That is, by increasing the resistance of the region where electrical and chemical flow is concentrated, some of it can be dispersed to other regions and overall uniformity can be improved. As a result, the region on the tab adjacent (ADJ) in the anode composite layer (CSH) can be prevented from overheating and being consumed, and the anode composite layer (CSH) can be induced to operate uniformly overall.

[0067] Referring again to FIG. 3, the first solid electrolyte layer (SEL1) may include a first surface (SF1) in which a first region (AR1) faces the positive active material layer (CML) and a second surface (SF2) in which a second region (AR2) faces the positive active material layer (CML). That is, the area of ​​the first region (AR1) may be the area of ​​the first surface (SF1), and the area of ​​the second region (AR2) may be the area of ​​the second surface (SF2).

[0068] In one embodiment, the area ratio of the first region (AR1) and the second region (AR2) with respect to the total area of ​​the first solid electrolyte layer (SEL1) may be in the range of 2:8 to 4:6. That is, the area of ​​the first region (AR1) may be 20% to 40% of the total area of ​​the first solid electrolyte layer (SEL1). If the area ratio of the first region (AR1) exceeds 40%, the first solid electrolyte layer (SEL1) contains an excessive amount of solid electrolyte particles of opposite diameters, which may cause the resistance of the entire anode composite layer (CSH) to become excessively high and, conversely, lead to a decrease in performance. If the area ratio of the first region (AR1) is less than 20%, the anode composite layer (CSH) cannot substantially produce the effects described above. By satisfying the above range, the anode composite layer (CSH) can improve overall electrical and chemical uniformity.

[0069] In another embodiment, referring to FIG. 5, the areas of the positive active material layer (CML) and the first solid electrolyte layer (SEL1) may differ from each other. For example, the area of ​​the positive active material layer (CML) may be smaller than the area of ​​the first solid electrolyte layer (SEL1). The width in the second direction (D2) of the positive active material layer (CML) and the first solid electrolyte layer (SEL1) may be the same, but the width in the first direction (D1) may differ. The positive composite layer (CSH) may further include an inert member (GSK) to compensate for the difference in area between the first solid electrolyte layer (SEL1) and the positive active material layer (CML). The inert member (GSK) may provide structural stability to the positive composite layer (CSH).

[0070] Cathode composite layer (ASH)

[0071] Hereinafter, with reference to FIGS. 6 to 10, other components of the unit cell (CEL) will be described with a focus on the negative electrode composite layer (ASH). Referring to FIG. 6, the unit cell (CEL) of the all-solid-state battery may include the positive electrode composite layer (CSH) and the negative electrode composite layer (ASH) described above. The unit cell (CEL) may be a stack of a positive electrode (CTH), a solid electrolyte layer (SEL), and a negative electrode (ANO), but may be a stack of a positive electrode composite layer (CSH) and a negative electrode composite layer (ASH).

[0072] The negative current collector (COL2) can provide a reference surface on which the negative coating layer (AML) is placed. The negative current collector (COL2) may comprise, for example, a material that does not react with lithium, that is, does not form either an alloy or a compound with lithium. For example, the negative current collector (COL2) may comprise 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 current collector (COL2) may be 1 μm to 20 μm, more specifically 5 μm to 15 μm, and more specifically 7 μm to 10 μm.

[0073] The negative current collector (COL2) may be composed of one of the metals described above, or may include an alloy of two or more metals or a coating material. The negative current collector (COL2) may, for example, have a plate-like or foil-like shape. Meanwhile, in one embodiment, the negative current collector (COL2) may be omitted.

[0074] Although not illustrated, the negative current collector (COL2) according to the embodiment may include a base film and a metal layer disposed on one or both sides of the base film. The base film may include, for example, a polymer. The polymer may be, for example, a thermoplastic polymer. The polymer may include, for example, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), or a combination thereof. The polymer may be an insulating polymer. By including an insulating thermoplastic polymer in the base film, the base film may soften or liquefy upon the occurrence of a short circuit, thereby interrupting battery operation and suppressing a sudden increase in current. The metal layer may include, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), or an alloy thereof. The negative current collector (COL2) may additionally include a metal piece and / or a lead tab. For more specific details regarding the base film, metal layer, metal chip, and lead tab of the negative current collector (COL2), refer to the anode current collector (110) described above. By having this structure, the negative current collector (COL2) can reduce the weight of the negative electrode (ASH) and, consequently, improve the energy density of the unit cell (CEL).

[0075] The negative electrode coating layer (AML) can be configured to allow lithium metal to grow between the unit cell (CEL) and the negative current collector (COL2) during charging. The negative electrode coating layer (AML) can serve as a protective layer for the lithium metal and simultaneously suppress the precipitation and growth of lithium dendrites.

[0076] The cathode coating layer (AML) may include metal particles and carbon. For example, the cathode coating layer (AML) 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 metal of the cathode coating layer (AML) can help lithium ions move toward the cathode current collector during charging and discharging of the all-solid-state battery.

[0077] The cathode coating layer (AML) may include at least one of amorphous carbon, crystalline carbon, or porous carbon. The cathode coating layer (AML) may include at least one carbon selected from the group consisting of carbon black, acetylene black, furnace black, ketjen black, and graphene. The carbon of the cathode coating layer (AML) can minimize volume change of the all-solid-state battery during charging and discharging and can provide structural stability of the cathode coating layer.

[0078] In one embodiment, the cathode coating layer (AML) may include a mixture (or composite) of carbon black and silver (Ag).

[0079] The thickness of the negative electrode coating layer (AML) may be smaller than that of the positive electrode active material layer (CML). The thickness of the negative electrode coating layer (AML) 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 (CML). The thickness of the negative electrode coating layer (AML) may be, for example, 1 µm to 20 µm, 2 µm to 10 µm, or 3 µm to 7 µm. If the thickness of the negative electrode coating layer (AML) is excessively thin, lithium dendrites formed between the negative electrode coating layer (AML) and the negative electrode current collector (COL2) may cause the negative electrode coating layer (AML) to collapse, thereby degrading the cycle characteristics of the unit cell (CEL). If the thickness of the cathode coating layer (AML) increases excessively, the energy density of the unit cell (CEL) decreases, and the internal resistance of the unit cell (CEL) caused by the cathode coating layer (AML) increases, which may degrade the cycle characteristics of the cell.

[0080] The cathode coating layer (AML) may further include other additives in addition to metal and carbon. The cathode coating layer (AML) may further include at least one additive selected from the group consisting of, for example, binders, fillers, coating agents, dispersants, and ion-conducting aids.

[0081] Meanwhile, although not illustrated, a carbon layer may be further included to improve adhesion between the cathode coating layer (AML) and the solid electrolyte layer (SEL).

[0082] In another embodiment, the negative electrode (ASH) of the unit cell (CEL) may further include a lithium metal layer (not shown) between the negative current collector (COL2) and the negative coating layer (AML). The thickness of the lithium metal layer may increase further during charging of the all-solid-state battery. The negative coating layer (AML) acts as a protective layer for the lithium metal layer and, at the same time, can suppress the growth of lithium dendrites from the lithium metal layer.

[0083] The lithium metal layer may be a thin metal film containing lithium or a lithium alloy. The lithium alloy is, for example, Li-Al alloy, Li-Sn alloy, Li-In alloy, Li-Ag alloy, Li-Au alloy, Li-Zn alloy, Li-Ge alloy, Li-Si alloy, etc., but is not limited to these; any alloy used as a lithium alloy is possible. The lithium metal layer may contain one of these alloys or lithium. Alternatively, the lithium metal layer may contain various types of alloys.

[0084] The lithium metal layer can serve as the negative electrode active material layer. That is, the negative electrode according to an embodiment of the present invention may use lithium or a lithium alloy as the negative electrode active material. The negative electrode active material may form a lithium metal layer or exist in a dispersed form within the negative electrode coating layer (AML). The negative electrode active material may exist within the lithium metal layer or the negative electrode coating layer (AML).

[0085] The cathode composite layer (ASH) may include a cathode current collector (COL2) and a cathode coating layer (AML) on the cathode current collector (COL2). As shown in FIG. 7, the cathode composite layer (ASH) may further include a second solid electrolyte layer (SEL2) on the cathode coating layer (AML). In this case, the second solid electrolyte layer (SEL2) may include a sulfide-based solid electrolyte, similar to the first solid electrolyte layer (SEL1).

[0086] Referring to FIG. 8, the area of ​​the positive active material layer (CML) of the positive composite layer (CSH) and the area of ​​the negative coating layer (AML) of the negative composite layer (ASH) may be substantially the same. The areas of the positive active material layer (CML), the first solid electrolyte layer (SEL1), and the negative coating layer (AML) may be substantially the same.

[0087] Referring to FIG. 9, the areas of the positive active material layer (CML) of the positive composite layer (CSH) and the negative coating layer (AML) of the negative composite layer (ASH) may differ from each other. For example, the area of ​​the positive active material layer (CML) may be smaller than the area of ​​the negative coating layer (AML). As another example, the areas of the positive active material layer (CML) and the first solid electrolyte layer (SEL1) on the positive active material layer (CML) may be the same, but the areas of the positive active material layer (CML) and the negative coating layer (AML) may differ.

[0088] Referring to FIG. 10, the unit cell (CEL) may further include an inert member (GSK). The inert member (GSK) can compensate for the area difference between the positive composite layer (CSH) and the negative composite layer (ASH) and provide structural stability to the unit cell (CEL). Specifically, the inert member (GSK) may be positioned on the positive current collector (COL1) and provided to surround at least one side of the positive active material layer (CML). The inert member (GSK) can compensate for the area difference between the positive active material layer (CML) and the negative coating layer (AML).

[0089] The inert member (GSK) may include, for example, a flame-retardant inert member. By providing flame retardancy, the inert member (GSK) can prevent thermal runaway and the possibility of ignition of the all-solid-state battery. Consequently, the inert member (GSK) can further enhance the safety of the all-solid-state battery. By the flame-retardant inert member absorbing residual moisture within the all-solid-state battery (10), the degradation of the all-solid-state battery can be prevented, thereby improving the lifespan characteristics of the all-solid-state battery.

[0090]

[0091] Method for manufacturing an all-solid-state battery

[0092] Hereinafter, a method for manufacturing an all-solid-state battery according to an embodiment of the present invention will be described with reference to FIGS. 11 to 16. The method for manufacturing an all-solid-state battery may include forming a positive electrode; forming a negative electrode; and forming a solid electrolyte layer. Specifically, the method for manufacturing an all-solid-state battery according to the present embodiment may include forming a positive electrode by forming a positive active material layer on a positive electrode current collector; forming a negative electrode by forming a negative electrode coating layer on a negative electrode current collector; and forming a solid electrolyte layer.

[0093] Forming the positive electrode may include preparing a positive electrode composition for forming a positive electrode active material layer and coating the positive electrode composition onto a positive electrode current collector. The positive electrode composition is composed of a positive electrode active material, a solid electrolyte, and a binder, and can be prepared by mixing these materials. Mixing the positive electrode composition may be selected from dry mixing or wet mixing and is not limited to a specific method. The same provisions previously described for all-solid-state batteries may apply to the positive electrode active material, solid electrolyte, and binder, which are components of the positive electrode composition.

[0094] Forming the cathode may include preparing a cathode composition for forming a cathode coating layer and coating the cathode composition onto a cathode current collector. The cathode composition is composed of metal particles, carbon-based materials, and binders, and may be prepared by mixing said materials. Likewise, the foregoing may apply equally to the components such as metal particles, carbon-based materials, and binders. Regarding the formation of the anode and cathode, the foregoing may be appropriately applied to embodiments of the present invention within the scope obvious to a person skilled in the art.

[0095] Hereinafter, a method for manufacturing an all-solid-state battery according to an embodiment of the present invention will be described in detail, focusing on forming a solid electrolyte layer. Forming the solid electrolyte layer may include forming a first composition; forming a second composition; forming a first region by coating the first composition; and forming a second region by coating the second composition.

[0096] Referring to FIG. 11, the first composition (ES1) can be formed by mixing the first precursor (PRE1). Additionally, the second composition (ES2) can be formed by mixing the second precursor (PRE2). More specifically, each of the first precursor (PRE1) and the second precursor (PRE2) may include various raw materials. That is, the first precursor (PRE1) and the second precursor (PRE2) can be defined as encompassing the raw materials described below.

[0097] For example, each of the first and second precursors (PRE1, PRE2) may include a sulfur (S) raw material, a phosphorus (P) raw material, and a halogen raw material. For example, the raw materials may include Li2S, P2S5, etc. Additionally, each of the first and second precursors (PRE1, PRE2) may further include a metal raw material. The halogen raw material may include at least one of a fluorine (F) raw material, a chlorine (Cl) raw material, a bromine (Br) raw material, or an iodine (I) raw material. The metal raw material may include a magnesium (Mg) raw material, a silver (Ag) raw material, a copper (Cu) raw material, etc. To obtain the desired solid electrolyte, the stoichiometric molar ratio of the raw materials may be varied, and the content of each of the raw materials may be varied.

[0098] The above-described raw materials may be mixed. For example, the raw materials may be processed by melt quenching or mechanical milling. In melt quenching, the starting materials may be mixed and formed into pellets. The pellets may be reacted under a predetermined reaction temperature and vacuum conditions. For example, the reaction temperature may be 400°C to 1000°C, preferably 800°C to 900°C. For example, the reaction time may be 0.1 hours to 12 hours, preferably 1 hour to 12 hours. Afterward, the pellets may be quenched. For example, the quenching temperature may be 10°C or lower, preferably 0°C or lower. For example, the quenching rate may be 1°C / sec to 10000°C / sec, preferably 1°C / sec to 1000°C / sec.

[0099] In the mechanical milling method, the raw materials may be stirred using a ball mill or the like. For example, the stirring speed may be 300 rpm to 10,000 rpm, 350 rpm to 5,000 rpm, or 370 rpm to 1,000 rpm. For example, the stirring time may be 10 to 1,000 hours, 10 to 100 hours, or 10 to 30 hours. The stirring speed and stirring time are not particularly limited, but a faster stirring speed can increase the rate of solid electrolyte production, and a longer stirring time can increase the solid electrolyte production rate. Stirring may be carried out under an inert atmosphere. The inert atmosphere may be, for example, an atmosphere containing nitrogen, argon, neon, helium, or a combination thereof.

[0100] The mixed mixture may be calcined under an inert atmosphere. For example, the inert atmosphere may be an atmosphere containing nitrogen, argon, neon, helium, or a combination thereof. Calcination may be carried out within a predetermined temperature range. For example, the calcination temperature may be from 0°C to 1000°C. For example, the calcination time may be from 1 hour to 48 hours.

[0101] The calcined mixture can be ground. The grinding method is not particularly limited, and a dry grinding or wet grinding process under a solvent can be performed. Grinding equipment such as a planetary mill, ball mill, jet mill, hammer mill, rotary mill, etc., can be used, and the calcined mixture can be ground using two or more grinding methods.

[0102] For example, a jet mill may be used for dry milling, and the milling speed of the jet mill may be about 100 rpm to 10,000 rpm, 500 rpm to 10,000 rpm, or 1,000 rpm to 10,000 rpm. The milling time of the jet mill may be 0.5 hours to 50 hours, 1 hour to 30 hours, or 1 hour to 24 hours. Dry grinding may be carried out at 0.1 MPa to 10 MPa, 1 MPa to 5 MPa, or 1 MPa to 3 MPa.

[0103] For example, a planetary mill containing zirconia balls may be used for wet milling. The stirring speed of wet milling may be 300 rpm to 10,000 rpm, 350 rpm to 5,000 rpm, or 370 rpm to 1,000 rpm. The time of wet milling may be 3 to 10 hours, 4 to 20 hours, or 5 to 10 hours. Wet milling may be carried out under a solvent, and the solvent may be a nonpolar solvent such as xylene or toluene.

[0104] As described above, the average particle size of the solid electrolyte particles produced can be controlled by controlling the type of grinding process and process conditions. The produced solid electrolyte particles may include an argyrodite-type sulfide-based solid electrolyte.

[0105] In one embodiment, the first composition (ES1) may include first solid electrolyte particles, and the second composition (ES2) may include second solid electrolyte particles. In this case, the average particle size of the first solid electrolyte particles may be larger than the average particle size of the second solid electrolyte particles. That is, by controlling process conditions, compositions having solid electrolyte particles of different particle sizes can be formed.

[0106] FIG. 12 illustrates the formation of a solid electrolyte layer (SEL) by coating a manufactured composition. A first region (AER1) may be formed by coating a first composition (ES1), and a second region (AER2) may be formed by coating a second composition (ES2). The first region (AER1) may include a first solid electrolyte particle, and the second region (AER2) may include a second solid electrolyte particle.

[0107] More specifically, a first region (AER1) having a first width (W1) can be formed by coating a first composition (ES1) in a first direction (D1). A second region (AER2) having a second width (W2) can be formed by coating a second composition (ES2) in a first direction (D1). The second region (AER2) can be formed parallel to the first region (AER1) with respect to the second direction (D2).

[0108] The first width (W1) and the second width (W2) may be different from each other. For example, the first width (W1) may be smaller than the second width (W2). By adjusting the first width (W1) and the second width (W2) during the process of coating the first and second compositions (ES1, ES2), the area ratio of the first region (AER1) and the second region (AER2) can be adjusted.

[0109] As shown in FIG. 12, the first and second compositions (ES1, ES2) can be coated on a substrate (SUB). The solid electrolyte layer (SEL) comprising the formed first and second regions (AER1, AER2) can be separated from the substrate (SUB) after drying and manufactured in the form of a self-supporting film.

[0110] Referring to FIG. 13, the first and second compositions (ES1, ES2) can be coated on an electrode (ESH). That is, the first and second compositions (ES1, ES2) can form first and second regions (AER1, AER2) on the electrode (ESH). At this time, the electrode (ESH) may be an anode or a cathode. Specifically, the first and second compositions (ES1, ES2) can be coated on the positive active material layer (CML) of the anode. Additionally, the first and second compositions (ES1, ES2) can be coated on the negative coating layer of the cathode. The first and second compositions (ES1, ES2) can be coated on the electrode (ESH) to form an electrode composite layer. For example, the first and second compositions (ES1, ES2) can be coated on the anode to form an anode composite layer.

[0111] In one embodiment, the electrode (ESH) may include a positive active material layer (CML) and may include an uncoated area, which is an uncoated region (NCA). A first composition (ES1) and a second composition (ES2) may be coated on the positive active material layer (CML). A first region (AER1) having a first width (W1) may be formed by coating the first composition (ES1) on the positive active material layer (CML) in a first direction (D1). A second region (AER2) having a second width (W2) may be formed by coating the second composition (ES2) on the positive active material layer (CML) in a first direction (D1). The second region (AER2) may be formed parallel to the first region (AER1) with respect to the second direction (D2). The formed first region (AER1) and second region (AER2) may constitute a first solid electrolyte layer (SEL1). As a result, an anode composite sheet (CST) including a first solid electrolyte layer (SEL1) formed on an anode active material layer (CML) can be formed. The thickness of the formed first solid electrolyte layer (SEL1) may be 10 μm to 200 μm.

[0112] In the anode composite sheet (CST), the first region (AER1) can be formed adjacent to the non-absorbent region (NCA). As shown in FIG. 13, the non-absorbent region (NCA), the first region (AER1), and the second region (AER2) can be arranged side by side with respect to the second direction (D2). The anode composite sheet (CST) can be cut into a predetermined size and shape. By cutting the anode composite sheet (CST), an anode composite layer (CSH) can be formed.

[0113] Referring to FIG. 14, the anode composite layer (CSH) may include an anode tab (CTB) formed by cutting a non-negative region (NCA). Specifically, the anode composite layer (CSH) may include an anode tab (CTB) protruding in a second direction (D2). In the anode composite layer (CSH), the direction of protrusion of the anode tab (CTB) and the direction of formation of the first and second regions (AER1, AER2) may be perpendicular to each other. Consequently, in the anode composite layer (CSH), the first region (AER1) of the first solid electrolyte layer (SEL1) may be adjacent to the anode tab (CTB).

[0114] Although the description is based on FIGS. 13 and 14, in the case of a solid electrolyte layer (SEL) formed on a separate substrate (SUB) as in FIG. 12, an anode composite layer can be formed by separately stacking it on the anode. In this case as well, an anode composite layer having the same structure can be formed by placing the first region (AER1) adjacent to the anode tab (CTB).

[0115] In one embodiment, the average particle size of the first solid electrolyte particles in the first region (AER1) and the second solid electrolyte particles in the second region (AER2) may be different from each other. The average particle size of the first solid electrolyte particles may be larger than the average particle size of the second solid electrolyte particles. Specifically, the average particle size of the first solid electrolyte particles may be 2 μm to 5 μm. The average particle size of the second solid electrolyte particles may be 0.5 μm to 2 μm.

[0116] By setting the average particle size of the first solid electrolyte particles to be relatively large, the average particle size of the solid electrolyte particles included in the region adjacent to the anode tab (CTB) in the first solid electrolyte layer (SEL1) increases. As the average particle size of the solid electrolyte particles increases, the resistance of the region adjacent to the anode tab (CTB) may increase. By intentionally increasing the resistance of the region adjacent to the anode tab (CTB), the flow of current within the unit cell can be distributed more uniformly.

[0117] The areas of the first region (AER1) and the second region (AER2) in the first solid electrolyte layer (SEL1) may differ from each other. In one embodiment, the area ratio of the first region (AER1) and the second region (AER2) may be 2:8 to 4:6. That is, the area of ​​the first region (AER1) may be 20% to 40% of the total area of ​​the first solid electrolyte layer (SEL1). If the area ratio of the first region (AER1) exceeds 40%, the first solid electrolyte layer (SEL1) contains an excessive amount of solid electrolyte particles of opposite diameter, which may cause the resistance of the entire anode composite layer (CSH) to become excessively high and, conversely, lead to a decrease in performance. If the area ratio of the first region (AER1) is less than 20%, the anode composite layer (CSH) cannot substantially produce the effects described above. By satisfying the above range, the anode composite layer (CSH) can improve overall electrical and chemical uniformity.

[0118] In this way, the electrical and chemical uniformity throughout the unit cell can be improved through the structural design of the solid electrolyte layer during the manufacturing stage of the all-solid-state battery. For example, problems caused by current concentration near the tab can be resolved by indirectly controlling the resistance of the solid electrolyte layer.

[0119] Referring to FIGS. 15 to 17, it can be seen that the components of the manufactured unit cell are stacked to form an all-solid-state battery unit cell. As shown in FIG. 14, one embodiment may include a positive electrode (CTH), a negative electrode (ANO), and a solid electrolyte layer (SEL) being manufactured separately and then stacked sequentially. As shown in FIGS. 15 and 16, another embodiment may include a positive electrode composite layer (CSH) and a negative electrode composite layer (ASH) being manufactured in the form of a positive electrode composite layer and then stacked. In this case, the positive electrode composite layer (CSH) may include a first solid electrolyte layer (SEL1), and in some cases, the negative electrode composite layer (ASH) may further include a second solid electrolyte layer (SEL2).

[0120] The stacked unit cells can undergo a formation process. The electrical and chemical stability of the manufactured unit cells can be improved through the formation process. Additionally, a lithium metal layer is formed on the anode through the formation process, allowing it to be used as an energy source. In other words, by manufacturing a unit cell with a cathode-free structure that does not contain anode active material during anode manufacturing, and then forming a lithium metal layer through the formation process, the energy density per unit volume can be improved.

[0121]

[0122] Hereinafter, embodiments of the present invention will be described in more detail through specific examples. However, these embodiments are intended to illustrate the present invention and the scope of the present invention is not limited to these embodiments.

[0123] (Preparation Example 1: Preparation of Anode)

[0124] LiNi as the positive active material 0.94 Co 0.04 Mn 0.02Particles of O2 with an average particle size of about 5 μm were prepared. As a solid electrolyte, an argyrodite-type crystal Li6PS5Cl with an average particle size of about 2 μm was prepared. PVdF-HFP was prepared as a binder. As a cathode slurry composition, a mixture of the aforementioned cathode active material, solid electrolyte, and binder was used.

[0125] (Preparation Example 2: Preparation of Cathode)

[0126] Carbon black (CB) was prepared as a carbon-based material and silver (Ag) particles were prepared as a metal particle. After mixing the carbon black and silver particles in a weight ratio of 3:1, 4 g of the mixed powder was placed in a container, and a mixed solution was prepared by adding 4 g of a methylpyrrolidone (NMP) solution containing 7 wt% of a polyvinylidene fluoride (PVDF) binder (Kureha # 9300).

[0127] A slurry was prepared by stirring the mixed solution while adding NMP little by little to the prepared mixed solution. The prepared slurry was applied to a SUS sheet using a bar coater, dried at 80°C in air for 10 minutes, and then vacuum dried at 40°C for 10 hours to produce a laminate. The surface of the prepared laminate was flattened by cold roll pressing to produce a cathode having a cathode coating layer / cathode current collector structure. At this time, the thickness of the cathode coating layer was approximately 15 μm, and the area of ​​the cathode coating layer and the cathode current collector were the same.

[0128] (Preparation of solid electrolyte layer)

[0129] A mixture was prepared by mixing 98.5 parts by weight of solid electrolyte particles and 1.5 parts by weight of an acrylic binder. A slurry was prepared by adding octyl acetate to the prepared mixture while stirring. The prepared slurry was applied using a bar coater onto a 15 μm thick nonwoven fabric placed on a 75 μm thick PET substrate, and a laminate was prepared by drying in air at 80°C for 10 minutes. A solid electrolyte layer was prepared by vacuum drying the prepared laminate at 80°C for 2 hours. The solid electrolyte layer is prepared in the manner described above, and its specific composition and form will be described later.

[0130] Preparation Example 3-1: First solid electrolyte particle (opposite)

[0131] A first solid electrolyte particle was prepared having the composition of Li6PS5Cl, an argyrodite-type crystal. The average particle size of the first solid electrolyte particle was approximately 3 μm.

[0132] Preparation Example 3-2: Second solid electrolyte particles (small particles)

[0133] A second solid electrolyte particle was prepared having the composition of Li6PS5Cl, an argyrodite-type crystal. The average particle size of the second solid electrolyte particle was about 1 μm.

[0134]

[0135] Example 1

[0136] An all-solid-state battery was prepared including the anode of Preparation Example 1 and the cathode of Preparation Example 2. A solid electrolyte layer was prepared including the first solid electrolyte particles of Preparation Example 3-1 and the second solid electrolyte particles of Preparation Example 3-2.

[0137] The solid electrolyte layer was prepared by dividing it into a first region and a second region. The first region contains the first solid electrolyte particles of Preparation Example 3-1, and the second region contains the second solid electrolyte particles of Preparation Example 3-2. The anode tab of the anode protrudes in a first direction, and the first region is positioned adjacent to the anode tab.

[0138] Specifically, the solid electrolyte layer was formed such that a first region had a constant width in the first direction, and a second region had a constant width in the first direction and was formed parallel to the first region. In the solid electrolyte layer, the area of ​​the first region was about 30%, and the area of ​​the second region was about 70%.

[0139] An all-solid-state battery was fabricated by stacking and pressurizing a positive electrode, a negative electrode, and a solid electrolyte layer. This pressurization process sinters the solid electrolyte layer, thereby improving battery characteristics. The thickness of the formed solid electrolyte layer was approximately 45 μm.

[0140]

[0141] Example 2

[0142] An all-solid-state battery was manufactured in the same manner as in Example 1, except that the area of ​​the first region was about 40% and the area of ​​the second region was about 60%.

[0143]

[0144] Comparative Example 1

[0145] An all-solid-state battery was prepared comprising the anode of Preparation Example 1 and the cathode of Preparation Example 2. A solid electrolyte layer comprising the first solid electrolyte particles of Preparation Example 3-1 was prepared. An all-solid-state battery was prepared by stacking and pressurizing the anode, cathode, and solid electrolyte layer. Through this pressurization process, the solid electrolyte layer is sintered, thereby improving battery characteristics. The thickness of the formed solid electrolyte layer was approximately 45 μm.

[0146] Comparative Example 2

[0147] An all-solid-state battery was manufactured in the same manner as in Example 1, except that the area of ​​the first region was about 10% and the area of ​​the second region was about 90%.

[0148] Comparative Example 3

[0149] An all-solid-state battery was manufactured in the same manner as in Example 1, except that the area of ​​the first region was about 60% and the area of ​​the second region was about 40%.

[0150] All-solid-state batteries according to the aforementioned examples and comparative examples are shown in Table 1 below.

[0151] Region 1 Region 2 Example 1 30% 70% Example 2 40% 60% Comparative Example 1 100% - Comparative Example 2 10% 90% Comparative Example 3 60% 40%

[0152] Evaluation Example 1: Battery Performance Evaluation

[0153] The performance of the all-solid-state battery according to the above-described examples and comparative examples was evaluated. Specifically, the first cycle was charged for 20 hours at a constant current of 0.05C until the battery voltage reached 4.2 V. Subsequently, discharge was performed for 20 hours at a current of 0.05C until the battery voltage reached 3.0 V.

[0154] The second cycle involved charging at a constant current of 0.33 C for about 3 hours until the battery voltage reached 4.2 V. Subsequently, discharging was performed at a constant current of 0.33 C for about 3 hours until the battery voltage reached 3.0 V.

[0155] Subsequently, the capacity retention rate was evaluated by repeating charging and discharging for 100 cycles under the same conditions as the second cycle. The capacity retention rate was evaluated as shown in Equation 1 below.

[0156] [Mathematical Formula 1]

[0157] Capacity Retention Rate[%] = [n-th cycle discharge capacity / 1st cycle discharge capacity] × 100

[0158] The capacity retention rate evaluated in this way was used as an indicator of life characteristics.

[0159] In addition, the capacity for each rate was evaluated by changing the rate (c-rate) during discharge. The capacity for each rate was measured by calculating the capacity measured at the initial rate (0.1C) and the capacity measured at the changed rate.

[0160] Specifically, the charging rate was fixed at 0.1C, while the discharging rate was changed to 0.5C and 1.0C and evaluated, respectively. The capacity of each at 0.5C and 1.0C was evaluated as a ratio to the capacity at 0.1C.

[0161] The results are shown in Table 2 below.

[0162] Capacity by Rate Limit (%) 0.5C / 0.1C Capacity by Rate Limit (%) 1.0C / 0.1C Life (%) @ 100 cycles Example 183.260.190.1 Example 281.259.290.1 ​​Comparative Example 19.33.090.0 Comparative Example 284.561.261.2 Comparative Example 322.09.190.2

[0163] Referring to the evaluation results above, it can be seen that the capacity and lifespan characteristics of the all-solid-state batteries according to the embodiments of the present invention are both excellent. Furthermore, referring to the capacity evaluation results by rate, it can be seen that while the decrease in capacity value as the rate increases is consistent across all examples, the decrease in the examples is relatively smaller. This implies that the overall electrochemical balance is optimized through compositional design, such as controlling the size of particles within the solid electrolyte layer and dividing regions within the electrolyte layer, and consequently, the performance of the battery is improved.

Claims

1. Positive current collector; A positive active material layer on the positive current collector above; and The above-mentioned positive active material layer includes a first solid electrolyte layer, wherein The above positive current collector includes a main body and a positive tab protruding in one direction from the main body, and The first solid electrolyte layer comprises a first region adjacent to the anode tab and a second region excluding the first region, and The first region comprises a first solid electrolyte particle, and the second region comprises a second solid electrolyte particle, wherein the average particle size of the first solid electrolyte particle is larger than the average particle size of the second solid electrolyte particle. The ratio of the area of ​​the first region to the area of ​​the second region is 2:8 to 4:6, Anode composite layer.

2. In Paragraph 1, The ratio of the average particle size of the first solid electrolyte particle to the average particle size of the second solid electrolyte particle is 2.0 to 5.0, Anode composite layer.

3. In Paragraph 1, The average particle size of the first solid electrolyte particles is 2 μm to 5 μm, Anode composite layer.

4. In Paragraph 1, The average particle size of the second solid electrolyte particles is 0.5 μm to 2 μm, Anode composite layer.

5. In Paragraph 1, Each of the above first solid electrolyte particles and second solid electrolyte particles is Li 7-a-c M a PS 6-c X c It comprises an argyrodite-type sulfide-based solid electrolyte represented by (0≤a≤2, 0≤c≤2), wherein X is F, Br, Cl, or a combination thereof, and The above M is scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof, Anode composite layer.

6. In Paragraph 1, A positive composite layer in which the area of ​​the positive active material layer and the area of ​​the first solid electrolyte layer are substantially the same.

7. In Paragraph 6, The main body comprises a first end and a second end facing each other in the one direction, and the first end crosses the boundary between the positive tab and the main body. The above main body part includes a tab adjacent part extending from the first end toward the second end, and The first area above is vertically overlapping with the adjacent tab area, Anode composite layer.

8. A cathode composite layer, wherein the cathode composite layer comprises a cathode current collector and a cathode coating layer on the cathode current collector; and All-solid-state battery comprising an anode composite layer according to claim 1.

9. In Paragraph 8, The above-mentioned all-solid-state battery further includes an inert member, and The areas of the positive active material layer of the positive composite layer and the negative coating layer of the negative composite layer are different from each other, The above-described inert member compensates for the difference in area between the positive electrode active material layer and the negative electrode coating layer, in an all-solid-state battery.

10. In Paragraph 8, The above cathode coating layer comprises metal particles and carbon-based materials, and The metal particles comprise at least one of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), or zinc (Zn), and The above carbon-based material comprises at least one of amorphous carbon, crystalline carbon, or porous carbon, in an all-solid-state battery.

11. In Paragraph 8, The above-described negative electrode composite layer further comprises a lithium metal layer between the negative electrode current collector and the negative electrode coating layer, and the lithium metal layer comprises lithium metal or an alloy of lithium metal, in an all-solid-state battery.

12. Forming a positive electrode by forming a positive electrode active material layer on a positive electrode current collector; Forming a cathode by forming a cathode coating layer on a cathode current collector; and Including forming a solid electrolyte layer, Forming the above solid electrolyte layer is: Forming a first composition comprising a first solid electrolyte; Forming a second composition comprising a second solid electrolyte; Coating the above-mentioned first composition in a first direction to form a first region having a first width; and The method includes coating the second composition in the first direction to form a second region having a second width parallel to the first region. The above positive current collector includes a positive tab protruding in a second direction, and The above solid electrolyte layer is arranged such that the first region is adjacent to the anode tab and the second direction, and A method for manufacturing an all-solid-state battery in which the average particle size of the first solid electrolyte is larger than the average particle size of the second solid electrolyte.

13. In Paragraph 12, Each of the first and second regions of the solid electrolyte layer is in contact with the positive active material layer, and the ratio of the area of ​​the first region to the area of ​​the second region is 2:8 to 4:6, Method for manufacturing an all-solid-state battery.

14. In Paragraph 12, The average particle size of the first solid electrolyte is 2 μm to 5 μm, Method for manufacturing an all-solid-state battery.

15. In Paragraph 12, The average particle size of the second solid electrolyte is 0.5 μm to 2 μm, Method for manufacturing an all-solid-state battery.

16. In Paragraph 12, The thickness of the solid electrolyte layer is 10 μm to 200 μm, Method for manufacturing an all-solid-state battery.

17. In Paragraph 12, A method for manufacturing an all-solid-state battery, wherein the first and second regions are formed by coating the first and second compositions on the positive active material layer.

18. In Paragraph 12, Each of the first and second solid electrolytes above is Li 7-a-c M a PS 6-c X c It comprises an argyrodite-type sulfide-based solid electrolyte represented by (0≤a≤2, 0≤c≤2), wherein X is F, Br, Cl, or a combination thereof, and The above M is scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof, Method for manufacturing an all-solid-state battery.

19. In Paragraph 12, The above cathode coating layer comprises metal particles and carbon-based materials, and The metal particles comprise at least one of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), or zinc (Zn), and A method for manufacturing an all-solid-state battery, wherein the carbon-based material comprises at least one of amorphous carbon, crystalline carbon, or porous carbon.

20. In Paragraph 12, It further includes forming the above-mentioned all-solid-state battery, A method for manufacturing an all-solid-state battery, wherein a lithium metal layer is formed between the negative electrode current collector and the negative electrode coating layer by forming the all-solid-state battery.

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