Solid Electrolyte for Solid-State Batteries, Solid-State Batteries, and Battery Packages

Abstract

Provided is a solid-state battery electrolyte for use in solid-state batteries that has better performance. The solid-state electrolyte for solid-state batteries has a lithium salt solid-state electrolyte portion and a non-lithium compound portion embedded in the lithium salt solid-state electrolyte portion.

Description

Technical Field

[0001] The present disclosure relates to a solid electrolyte for a solid-state battery, a solid-state battery including the same, and a battery package.

Background Art

[0002] Due to the widespread use of various electronic devices such as mobile phones, the development of secondary batteries is underway as a power source that is small and lightweight and can obtain a high energy density. This secondary battery includes a positive electrode, a negative electrode, and an electrolyte housed inside an exterior member. In recent years, instead of a liquid or gel electrolyte containing an organic solvent or the like, the development of a solid-state battery, which is a secondary battery including a solid electrolyte, has been made (see, for example, Patent Documents 1 and 2 and Non-Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0004]

Non-Patent Document Ⅰ

Summary of the Invention

[0005] As described in the above prior art documents, various studies have been made to improve the performance of solid-state batteries. However, there is still room for improvement in the performance of solid-state batteries.

[0006] Therefore, a solid electrolyte for a solid-state battery having excellent performance is desired.

[0007] The solid electrolyte for a solid-state battery according to one embodiment of the present disclosure has a lithium salt solid electrolyte portion and a non-lithium compound portion embedded in the lithium salt solid electrolyte portion.

[0008] According to the solid electrolyte for a solid-state battery of one embodiment of the present disclosure, since the lithium salt solid electrolyte portion and the non-lithium compound portion containing no lithium are combined, excellent performance such as having good ionic conductivity and obtaining chemical stability can be exhibited.

[0009] Note that the effects of the present disclosure are not necessarily limited to the effects described here, and may be any of a series of effects related to the present disclosure described later.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0011] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The order of description is as follows. 0. Outline of the Present Disclosure 1. First Embodiment 1.1 Configuration of the Solid Electrolyte for a Solid-State Battery 1.2 Manufacturing Method of the Solid Electrolyte for a Solid-State Battery 1.3 Action and Effects of the Solid Electrolyte for a Solid-State Battery 2. Second Embodiment 2.1 Battery Package 2.2 Solid battery 2.3 Coating part 2.4 Method for manufacturing battery package 2.5 Function and effect 3. Applications of battery package 4. Examples The "solid battery" of the present disclosure refers to a battery whose components are solid. For example, the "solid battery" of the present disclosure is a laminated solid battery formed by laminating a plurality of layers. The plurality of layers are made of, for example, a sintered body. The "solid battery" of the present disclosure includes not only secondary batteries that can repeatedly charge and discharge, but also primary batteries that can only discharge.

[0012] [0. Summary of the present disclosure] First, the summary of the present disclosure will be described. So far, various studies have been made on improving the performance of solid batteries. Since solid batteries are equipped with solid electrolytes, generally, they are superior in high-temperature resistance and have high safety compared to batteries using liquid electrolytes.

[0013] However, inorganic solid electrolytes are generally in particle form, and lithium has to move across the interfaces between solid electrolyte particles. Even if the material has a high lithium ion conductivity (bulk conductivity) inside the particles, the lithium ion conductivity (grain boundary conductivity) at the particle interfaces is likely to decrease.

[0014] In Patent Document 1 mentioned above, by mixing Li-oxide solid electrolyte particles (Li7La3Zr2O 12 ) having a garnet structure with an ionic liquid, the interfaces between solid electrolyte particles are formed via the ionic liquid to constitute a solid-liquid mixed electrolyte with high lithium ion conductivity. However, since it is a liquid-containing cell, there is a concern about the leakage of the ionic liquid, so sealing measures different from those of all-solid batteries are required.

[0015] Also, in Non-Patent Document 1 mentioned above, solid electrolyte particles (Li7La3Zr2O 12) and a solid electrolyte (Li3OCl) having a low melting point antiperovskite structure are mixed, the antiperovskite type solid electrolyte is melted and brought into contact with the garnet type solid electrolyte to form a mixed solid electrolyte layer with small voids. In the solid electrolyte of Non-Patent Document 2, an ionic conductivity of 1×10 -4 S / cm is obtained. However, in addition to being expensive, Li oxide solid electrolytes having a garnet structure or a perovskite structure are liable to have the Li state on the surface of the substance altered. Specifically, changes such as a change to a state where Li is excessive, a change to a state where Li is deficient, or the formation of heterogeneous phases such as Li2O, Li2CO3, and LiOH are likely to occur. Such alteration of the Li state on the substance surface is accompanied by a large change in the interfacial resistance. Therefore, even in the case of a mixed solid electrolyte, the high lithium ion conductivity of the Li oxide solid electrolyte may not be utilized.

[0016] Also, in Non-Patent Document 2, a mixed solid electrolyte layer of Li oxide solid electrolyte particles (Li7La3Zr2O 12 ) and lithium halide hydrate (LiI·3H2O) in which an ionic conductivity of 6.2×10 -3 S / cm is obtained is disclosed. However, Li oxide solid electrolytes have a property of being liable to cause a deterioration reaction due to moisture. There is a possibility that a deterioration reaction of the Li oxide solid electrolyte particles may occur due to the moisture derived from the hydrate of LiI·3H2O contained in the mixed solid electrolyte layer. In that case, the ionic conductivity decreases during long-term use. For example, the dehydration start temperature of LiCl·3H2O is about 50°C, and stable operation at a high temperature of 50°C or higher is difficult. Furthermore, since almost all dehydration occurs at 100°C, various side reactions due to the generated moisture at 100°C will cause deterioration of the battery characteristics.

[0017] In view of the above circumstances, the present applicant proposes below a solid electrolyte for a solid battery having excellent performance such as being less liable to cause a deterioration reaction due to moisture and having higher ionic conductivity, and a solid battery using the same.

[0018] [1. First Embodiment] <1.1 Configuration of Solid Electrolyte for Solid-State Batteries> Referring to FIG. 1, the solid electrolyte for a solid-state battery according to the first embodiment of the present disclosure will be described. FIG. 1 is a schematic cross-sectional view schematically showing a configuration example of the solid electrolyte for a solid-state battery. The solid electrolyte for a solid-state battery in FIG. 1 is a mixture including a first portion 31 and a second portion 32.

[0019] The first portion 31 is a portion containing a lithium salt solid electrolyte. The first portion 31 has an inverse perovskite structure. The first portion 31 preferably has a melting point of 400 °C or lower. Specifically, the first portion 31 is Li3OCl, Li2(OH)Cl, and Li2(OH)Cl 0.9 F 0.1 and preferably contains at least one of them. The lattice constant of Li3OCl, the lattice constant of Li2(OH)Cl, and Li2(OH)Cl 0.9 F 0.1 are all 3.91 Å. Further, the first portion 31 may be at least one of those in which all or part of Cl in Li3OCl and Li2(OH)Cl is substituted with F (fluorine), Br (bromine), or I (iodine).

[0020] The second portion 32 is embedded in the first portion 31 and is a portion containing a non-lithium compound. The non-lithium compound does not have to be an electrolyte. The non-lithium compound portion is made of an inorganic insulating material. The inorganic insulating material is, for example, a metal oxide or a metal nitride. Specifically, as the inorganic insulating material, at least one of Al2O3, ZrO2, and TiO2 can be used. Further, Nb2O5 or BaTiO3 may be used as the inorganic insulating material for the non-lithium compound portion. Note that the insulating material referred to in the present disclosure means, for example, a material having a band gap of 3.5 eV or more.

[0021] A plurality of second portions 32 are discretely provided in the first portion 31. The first portion 31 is provided so as to fill the gaps between the plurality of second portions 32. Also, the median diameter D50 of the plurality of second portions 32 is preferably 5 nm or more and 5 μm or less. The first portion 31 is obtained by allowing a lithium molten salt obtained by melting a lithium salt solid electrolyte to penetrate into the gaps between the plurality of second portions 32 and then crystallizing it. The first portion 31 is preferably meltable at a temperature of less than 400°C.

[0022] <1.2 Method for manufacturing a solid electrolyte for a solid-state battery> Next, an example of a method for manufacturing a solid electrolyte for a solid-state battery will be described. First, a solid electrolyte powder that will become the first portion 31, a non-lithium compound powder that will become the second portion 32, and an organic binder are kneaded to produce a kneaded powder. Next, a compression molded body is produced by heating and compression molding the kneaded powder by a hot isostatic pressing (HIP) method or the like. At that time, it is desirable to perform compression molding while heating at a temperature at which the solid electrolyte powder melts (for example, a temperature of 200°C or more and less than 400°C). By such heat compression molding, dehydration from the kneaded powder is performed, and the first portion 31 and the second portion 32 are ionically bonded. Thus, the solid electrolyte for a solid-state battery of the present embodiment is obtained.

[0023] <1.3 Action and effect of the solid electrolyte for a solid-state battery> In this solid electrolyte for a solid-state battery, a plurality of second portions 32 containing a non-lithium compound are embedded in the first portion 31 containing a lithium salt solid electrolyte. By combining the lithium salt solid electrolyte portion and the non-lithium compound portion that does not contain lithium in this way, the solid electrolyte for a solid-state battery of the present embodiment can exhibit excellent performance such as having good ionic conductivity. Therefore, according to this solid electrolyte for a solid-state battery, a high ionic conductivity can be obtained, and rapid charging and high output are possible when used in a solid-state battery.

[0024] In addition, since the solid electrolyte for this solid-state battery can be made to not contain a Li-oxide solid electrolyte, it is excellent in chemical stability as compared with the case of containing a Li-oxide solid electrolyte. As described above, a Li-oxide solid electrolyte easily reacts with water and has a property of being easily deteriorated. For this reason, a Li-oxide solid electrolyte is easily affected by humidity changes (humidity environment) and is difficult to handle. In that regard, since the solid electrolyte for the solid-state battery of the present embodiment can be made to not contain a Li-oxide solid electrolyte, high chemical stability can be obtained.

[0025] [2. Second Embodiment] <2.1 Battery Package 100> Next, the battery package 100 of the second embodiment of the present disclosure will be described. FIG. 2 is a schematic cross-sectional view schematically showing the overall configuration of the battery package 100. The battery package 100 includes a solid-state battery 101 and a covering portion 102 that covers the solid-state battery 101. The solid-state battery 101 is protected from the external environment by the covering portion 102. The covering portion 102 suppresses, for example, the intrusion of water vapor into the solid-state battery 101. Hereinafter, the solid-state battery 101 will be described, and then the covering portion 102 will be described. The "water vapor" referred to here refers to moisture typified by water vapor in the atmosphere, and in a preferred embodiment, it means moisture including not only water vapor having a gas form but also liquid water. Preferably, the solid-state battery 101 with such moisture permeation prevented is packaged so as to be suitable for board mounting, and in particular, is packaged so as to be suitable for surface mounting.

[0026] <2.2 Solid-State Battery 101> FIG. 3 is a schematic cross-sectional view schematically showing the configuration of the solid-state battery 101. As shown in FIGS. 2 and 3, the solid-state battery 101 has a laminate 5, a positive electrode terminal 6, and a negative electrode terminal 7. The positive electrode terminal 6 and the negative electrode terminal 7 are provided so as to face each other with the laminate 5 interposed therebetween. As shown in FIG. 4, the laminate 5 is formed by laminating a positive electrode layer 10, a negative electrode layer 20, and a solid electrolyte layer 30 in the Z-axis direction. The solid electrolyte layer 30 is interposed between the positive electrode layer 10 and the negative electrode layer 20 in the Z-axis direction, which is the lamination direction. Specifically, the solid-state battery 101 has a structure in which a unit U in which a negative electrode layer 20, a solid electrolyte layer 30, a positive electrode layer 10, and a solid electrolyte layer 30 are laminated in this order is repeatedly laminated in the Z-axis direction. In FIG. 3, a solid-state battery 101 including two units U is illustrated, but the solid-state battery 101 is not limited to this embodiment and may include three or more units U. The solid-state battery 101 may further have blank layers 41 and 42 which are electron insulating layers. The blank layer 41 is provided in the same layer as a part of the positive electrode layer 10. The blank layer 42 is provided in the same layer as a part of the negative electrode layer 20.

[0027] The positive electrode layer 10 and the negative electrode layer 20 may contain a conductive auxiliary agent. Examples of the conductive auxiliary agent that can be included in the positive electrode layer 10 and the negative electrode layer 20 include at least one selected from metal materials such as silver, palladium, gold, platinum, copper, and nickel, and carbon. The conductive auxiliary agent contained in the positive electrode layer 10 and the conductive auxiliary agent contained in the negative electrode layer 20 may be of the same type or different types.

[0028] (Positive Electrode Layer 10) The positive electrode layer 10 is an electrode layer containing at least a positive electrode active material. In the solid-state battery 101 shown in FIG. 3, the positive electrode layer 10 has a laminated structure including a positive electrode current collector 11 and a pair of positive electrode active material layers 12 and 13.

[0029] The positive electrode current collector 11 is a metal foil such as aluminum foil, for example. In FIG. 3, a form in which the positive electrode layer 10 includes the positive electrode current collector 11 is illustrated, but the positive electrode current collector 11 is not an essential component. The positive electrode layer 10 may be in a form that includes either the positive electrode active material layer 12 or the positive electrode active material layer 13 without including the positive electrode current collector 11.

[0030] (Positive electrode active material layers 12, 13) The positive electrode active material layers 12, 13 contain a positive electrode active material as a main component. The positive electrode active material layer 12 is provided on the upper surface of the positive electrode current collector 11, and the positive electrode active material layer 13 is provided on the lower surface of the positive electrode current collector 11.

[0031] The positive electrode active material contained in the positive electrode active material layers 12, 13 is a material that is involved in the insertion and extraction of ions in the solid battery 101 and is also involved in the transfer of electrons with an external circuit. Through the solid electrolyte, ions move (i.e., ion-conduct) between the positive electrode layer 10 and the negative electrode layer 20. The insertion and extraction of ions into and from the positive electrode active material involve the oxidation or reduction of the positive electrode active material. Electrons or holes for such redox reactions are transferred from the external circuit to the positive electrode terminal 6 or the negative electrode terminal 7, and further transferred to the positive electrode layer 10 or the negative electrode layer 20 so that charge and discharge proceed. The positive electrode active material layers 12, 13 are layers capable of inserting and extracting, for example, lithium ions, sodium ions, protons (H + ), potassium ions (K + ), magnesium ions (Mg 2+ ), aluminum ions (Al 3+ ), silver ions (Ag + ), fluoride ions (F - ) or chloride ions (Cl - ). That is, it is preferable that the solid battery 101 is an all-solid-state secondary battery in which the above ions move between the positive electrode layer 10 and the negative electrode layer 20 through the solid electrolyte to perform charge and discharge.

[0032] (Positive electrode active material) Examples of the positive electrode active material contained in the positive electrode layer 10 include at least one selected from the group consisting of a lithium-containing phosphate compound having a NASICON-type structure, a lithium-containing phosphate compound having an olivine-type structure, a lithium-containing layered oxide, and a lithium-containing oxide having a spinel-type structure. An example of the lithium-containing phosphate compound having a NASICON-type structure is Li3V2(PO4)3. An example of the lithium-containing phosphate compound having an olivine-type structure is Li3Fe2(PO4)3, LiFePO4, LiMnPO4, LiFe 0.6 Mn 0.4 PO4, etc. An example of the lithium-containing layered oxide is LiCoO2, LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O2, LiCo 0.8 Ni 0.15 Al 0.05 O2, etc. An example of the lithium-containing oxide having a spinel-type structure is LiMn2O4, LiNi 0.5 Mn 1.5 O4, etc.

[0033] In addition, examples of the positive electrode active material capable of occluding and releasing sodium ions include at least one selected from the group consisting of a sodium-containing phosphate compound having a NASICON-type structure, a sodium-containing phosphate compound having an olivine-type structure, a sodium-containing layered oxide, and a sodium-containing oxide having a spinel-type structure.

[0034] (Negative electrode layer 20) The negative electrode layer 20 is an electrode layer containing at least a negative electrode active material. The negative electrode layer 20 may have a negative electrode current collector. The negative electrode current collector is, for example, a metal foil such as a copper foil.

[0035] (Negative electrode active material) The negative electrode active material contained in the negative electrode layer 20, similar to the positive electrode active material contained in the positive electrode layer 10, is a material that participates in the insertion and extraction of ions in the solid battery 101 and also participates in the transfer of electrons with the external circuit. Through the solid electrolyte layer 30, ions move (i.e., ion-conduct) between the positive electrode layer 10 and the negative electrode layer 20. The insertion and extraction of ions into and from the negative electrode active material involve oxidation or reduction of the negative electrode active material. Electrons or holes for such redox reactions are transferred from the external circuit to the positive electrode terminal 6 or the negative electrode terminal 7, and further transferred to the positive electrode layer 10 or the negative electrode layer 20, so that charge and discharge proceed. The negative electrode active material can insert and extract, for example, lithium ions, sodium ions, protons (H + ), potassium ions (K + ), magnesium ions (Mg 2+ ), aluminum ions (Al 3+ ), silver ions (Ag + ), fluoride ions (F - ) or chloride ions (Cl - ). Examples of the negative electrode active material contained in the negative electrode layer 20 include at least one oxide containing at least one element selected from the group consisting of Ti, Si, Sn, Cr, Fe, Nb, and Mo, graphite-lithium compounds, lithium alloys, lithium-containing phosphate compounds having a NASICON-type structure, lithium-containing phosphate compounds having an olivine-type structure, and lithium-containing oxides having a spinel-type structure, etc. At least one selected from the group consisting thereof. An example of the lithium alloy is Li-Al, etc. Examples of the lithium-containing phosphate compound having a NASICON-type structure include Li3V2(PO4)3, LiTi2(PO4)3, etc. Examples of the lithium-containing phosphate compound having an olivine-type structure include Li3Fe2(PO4)3, LiCuPO4, etc. An example of the lithium-containing oxide having a spinel-type structure is Li4Ti5O 12 , etc.

[0036] In addition, examples of the negative electrode active material capable of occluding and releasing sodium ions include at least one selected from the group consisting of sodium-containing phosphate compounds having a NASICON-type structure, sodium-containing phosphate compounds having an olivine-type structure, and sodium-containing oxides having a spinel-type structure.

[0037] (Solid electrolyte layer 30) The solid electrolyte layer 30 forms a layer through which, for example, lithium ions can be conducted between the positive electrode layer 10 and the negative electrode layer 20. As the solid electrolyte layer 30, the solid electrolyte for a solid battery described in the first embodiment can be employed.

[0038] (Positive electrode terminal 6 and negative electrode terminal 7) The positive electrode terminal 6 and the negative electrode terminal 7 are external connection terminals for connecting the laminate 5 to an external device. The positive electrode terminal 6 and the negative electrode terminal 7 are preferably provided as end face electrodes on the side surface of the laminate 5. That is, the positive electrode terminal 6 and the negative electrode terminal 7 extend along the Z-axis direction which is the stacking direction of the laminate 5. In FIG. 3, the positive electrode terminal 6 and the negative electrode terminal 7 are arranged to face each other in the X-axis direction. As shown in FIG. 3, the positive electrode terminal 6 is electrically connected to the end face of the positive electrode current collector 11 of the positive electrode layer 10. The negative electrode terminal 7 is electrically connected to the end face of the negative electrode layer 20. The positive electrode terminal 6 and the negative electrode terminal 7 are preferably made of a material having a high conductivity. Examples of the constituent material of the positive electrode terminal 6 and the constituent material of the negative electrode terminal 7 include at least one selected from the group consisting of gold, silver, platinum, aluminum, tin, nickel, copper, manganese, cobalt, iron, titanium, and chromium. However, the constituent materials of the positive electrode terminal 6 and the negative electrode terminal 7 are not limited to the above.

[0039] (Margin layers 41, 42) The margin layer 41 has margin portions 411 to 413. The margin portion 411 is in the same layer as the positive electrode current collector 11 and is provided between the positive electrode current collector 11 and the negative electrode terminal 7. The margin portion 412 is in the same layer as the positive electrode active material layer 12 and is provided between the positive electrode active material layer 12 and the positive electrode terminal 6 and between the positive electrode active material layer 12 and the negative electrode terminal 7, respectively. The margin portion 413 is in the same layer as the positive electrode active material layer 13 and is provided between the positive electrode active material layer 13 and the positive electrode terminal 6 and between the positive electrode active material layer 13 and the negative electrode terminal 7, respectively. The margin layer 42 is in the same layer as the negative electrode layer 20 and is provided between the negative electrode layer 20 and the positive electrode terminal 6.

[0040] Examples of the constituent materials of the margin portions 411 to 413 of the margin layer 41 and the margin layer 42 include materials having electron insulation properties (hereinafter simply referred to as insulating materials).

[0041] Examples of the insulating material include glass materials and ceramic materials. The glass materials include, but are not limited to, the following: for example, soda lime glass, potassium glass, borate glass, borosilicate glass, barium borosilicate glass, boric acid salt glass, barium borate glass, bismuth borosilicate salt glass, bismuth zinc borate glass, bismuth silicate glass, phosphate glass, aluminophosphate glass, and at least one selected from the group consisting of phosphite glass. Further, examples of the ceramic material include, but are not limited to, the following: for example, aluminum oxide (Al2O3), boron nitride (BN), silicon dioxide (SiO2), silicon nitride (Si3N4), zirconium dioxide (ZrO2), aluminum nitride (AlN), silicon carbide (SiC), and barium titanate (BaTiO3).

[0042] The insulating materials forming the blank layers 41 and 42 may contain a solid electrolyte. In that case, the solid electrolyte contained in the insulating material is preferably the same material as the solid electrolyte contained in the solid electrolyte layer 30. By adopting such a configuration, the bonding property between the blank layers 41 and 42 and the solid electrolyte layer 30 can be further improved.

[0043] <2.3 Coating portion 102> As shown in FIG. 2, the coating portion 102 of the battery package 100 includes a support substrate 102A, a coating insulating film 102B, and a coating inorganic film 102C. In the battery package 100, the entire solid battery 101 is surrounded by the coating portion 102. That is, the coating portion 102 is provided so that the solid battery 101 is not exposed to the outside.

[0044] (Support substrate 102A) The support substrate 102A is a plate-like member that supports the solid battery 101. The support substrate 102A has a surface 102S that faces the bottom surface 101B, which is the main surface of the solid battery 101. The support substrate 102A may be a resin substrate or a ceramic substrate. In a preferred embodiment, the support substrate 102A is a ceramic substrate. The support substrate 102A contains ceramic as a main component. If the support substrate 102A is a ceramic substrate, it is preferable because it is excellent in preventing the permeation of water vapor and also has excellent heat resistance. The ceramic substrate can be obtained, for example, by firing a green sheet laminate. Specifically, the ceramic substrate may be, for example, an LTCC (Low Temperature Co-fired Ceramics) substrate or an HTCC (High Temperature Co-fired Ceramic) substrate. However, this is only an example. The thickness of the support substrate 102A is 20 μm or more and 1000 μm or less, and may be, for example, 100 μm or more and 300 μm or less.

[0045] (Coating insulating film 102B) The coating insulating film 102B is a layer provided so as to cover at least the upper surface 101A and the side surface 101C of the solid battery 101. As shown in FIG. 2, the solid battery 101 provided on the support substrate 102A is entirely wrapped by the coating insulating film 102B. In a preferred embodiment, the coating insulating film 102B is provided so as to cover all of the upper surface 101A and the side surface 101C of the solid battery 101. It means the surface that is positioned relatively upward among the two main surfaces constituting the solid battery 101. Among the two main surfaces constituting the solid battery 101, the surface positioned relatively downward is the bottom surface 101B. Therefore, the upper surface 101A is the main surface located on the side opposite to the support substrate 102A. Therefore, the coating insulating film 102B preferably covers all of the surfaces of the solid battery 101 other than the bottom surface 101B. The coating insulating film 102B is made of, for example, a resin material capable of blocking water vapor. The coating insulating film 102B forms a suitable water vapor barrier in combination with the coating inorganic film 102C. Examples of the material used for the coating insulating film 102B include epoxy resins, silicone resins, and liquid crystal polymers. However, it is merely an example, and the thickness of the coating insulating film 102B is 30 μm or more and 1000 μm or less, and may be, for example, 50 μm or more and 300 μm or less.

[0046] (Coating inorganic film 102C) The coated inorganic film 102C is provided so as to cover the coated insulating film 102B. Since the coated inorganic film 102C is positioned on the coated insulating film 102B, together with the coated insulating film 102B, it has a form that largely wraps the entire solid-state battery 101 on the support substrate 102A. The material of the coated inorganic film 102C is not particularly limited as long as it is an inorganic material. The coated inorganic film 102C may be a metal, glass, oxide ceramics, or a mixture thereof. In a certain preferred embodiment, the coated inorganic film 102C contains a metal component. That is, the coated inorganic film 102C may be a metal thin film. Merely by way of example, the thickness of the coated inorganic film 102C is 0.1 μm or more and 100 μm or less, and may be, for example, 1 μm or more and 50 μm or less. The coated inorganic film 102C may be a dry plating film. The dry plating film referred to here is a film obtained by a vapor phase method such as physical vapor deposition (PVD) or chemical vapor deposition (CVD), and is a thin film having a very thin thickness on the nano-order or micron-order. The dry plating film, which is a thin film, contributes to the miniaturization and thinning of the battery package 100. The dry plating film preferably contains at least one selected from the group consisting of, for example, aluminum (Al), nickel (Ni), palladium (Pd), silver (Ag), tin (Sn), gold (Au), copper (Cu), titanium (Ti), platinum (Pt), silicon (Si), and stainless steel. A dry plating film composed of such components is chemically and thermally stable, so it is excellent in chemical resistance, weather resistance, heat resistance, etc., and a solid-state battery 101 with improved long-term reliability is provided.

[0047] In the battery package 100 shown in FIG. 3, the support substrate 102A is a terminal substrate provided with a substrate wiring 8 including external terminals for connecting the solid-state battery 101 and an external device. The substrate wiring 8 in the support substrate 102A serving as the terminal substrate is not particularly limited as long as it enables electrical connection between the upper surface and the lower surface of the support substrate 102A. In FIG. 2, a substrate wiring 8 including vias 8A and a pair of lands 8B and 8C is provided on the support substrate 102A. The land 8B is exposed on the upper surface of the support substrate 102A and is electrically connected to the positive electrode terminal 6 or the negative electrode terminal 7. The land 8C is exposed on the lower surface of the support substrate 102A. The via 8A penetrates the support substrate 102A so as to connect the land 8B and the land 8C.

[0048] <2.4 Manufacturing Method> Subsequently, a manufacturing method of the battery package 100 of the present disclosure will be briefly described. The battery package 100 can be manufactured, for example, by a process of manufacturing the solid-state battery 101 and a process of packaging the solid-state battery 101.

[0049] (Process of manufacturing the solid-state battery 101) In manufacturing the laminate 5 of the solid-state battery 101, a printing method such as a screen printing method, a green sheet method using a green sheet, or a composite method thereof can be used.

[0050] Hereinafter, one manufacturing method will be exemplified and described, but the present disclosure is not limited to the following manufacturing method. Also, matters over time such as the following description order are merely for convenience of explanation and the present disclosure is not limited to those matters.

[0051] First, a positive electrode layer 10 is fabricated. Specifically, after preparing a positive electrode current collector 11, a positive electrode active material particle, a resin, and a solvent are mixed to form a positive electrode slurry. Next, the positive electrode slurry is applied to both sides of the positive electrode current collector 11, and then the applied positive electrode slurry is dried to form a green sheet for the positive electrode. Further, the fabricated green sheet for the positive electrode is impregnated by dropping a molten solid electrolyte for the positive electrode or the like. As the molten solid electrolyte for the positive electrode, Li2CO3, Li2SO4, Li3BO3, Li3OCl, Li2OHCl, Li2(OH)Cl 0.9 F 0.1 , Li2(OH)Cl 0.9 Br 0.1 and Li2(OH)Cl 0.9 I 0.1 at least one of which may be used. Thus, the positive electrode layer 10 is obtained.

[0052] Next, a negative electrode layer 20 is fabricated. Specifically, a negative electrode active material particle, a resin, and a solvent are mixed to form a negative electrode slurry. Subsequently, the negative electrode slurry is applied onto a film, and then the applied negative electrode slurry is dried to form a green sheet for the negative electrode. Further, the fabricated green sheet for the negative electrode is impregnated by dropping a molten solid electrolyte for the negative electrode or the like. As the molten solid electrolyte for the negative electrode, Li2CO3, Li2SO4, Li3BO3, Li3OCl, Li2OHCl, Li2(OH)Cl 0.9 F 0.1 , Li2(OH)Cl 0.9 Br 0.1 and Li2(OH)Cl 0.9 I 0.1 at least one of which may be used. Thus, the negative electrode layer 20 is obtained.

[0053] Next, a solid electrolyte layer 30 is fabricated according to the procedure described in the first embodiment above.

[0054] Furthermore, an insulating paste is fabricated by mixing an insulating material, a binder, an organic binder, a solvent, and an optional additive, etc.

[0055] Subsequently, a positive electrode layer 10, a solid electrolyte layer 30, a negative electrode layer 20, and a solid electrolyte layer 30 are laminated in this order to produce a laminated structure. This laminated structure corresponds to one unit U shown in FIG. 4. When producing this laminated structure, an insulating paste is applied to the locations where the blank layers 41 and 42 should be formed. After impregnating the laminated structure by dripping a molten solid electrolyte for the solid electrolyte layer or the like, it is dried. As a result, the solid electrolyte layer 30 is obtained by impregnating the solid electrolyte sintered body with the solid electrolyte. As the molten solid electrolyte for the solid electrolyte layer, a lithium molten salt containing at least one of Li2CO3, Li2SO4, Li3BO3, Li3OCl, and Li2OHCl may be used. The dried laminated structure is compressed by a cold isostatic pressing (CIP) method or the like to crimp the positive electrode layer 10, the solid electrolyte layer 30, the negative electrode layer 20, and the solid electrolyte layer 30. Finally, the laminate 5 is obtained by firing at a temperature below 800°C in a nitrogen atmosphere.

[0056] Next, a conductive paste is applied to the side surface of the sintered laminate 5 where a part of the positive electrode layer 10 is exposed. Thereby, the positive electrode terminal 6 can be formed. Similarly, a conductive paste is applied to the side surface of the sintered laminate 5 where a part of the negative electrode layer 20 is exposed. Thereby, the negative electrode terminal 7 can be formed. Note that the positive electrode terminal 6 and the negative electrode terminal 7 are not limited to being formed on the sintered laminate 5, and may be formed on the laminated structure before firing and sintered simultaneously with the laminated structure.

[0057] Thus, the solid battery 101 can be obtained.

[0058] (Step of packaging the solid battery 101) First, prepare a support substrate 102A. The support substrate 102A can be obtained, for example, by laminating and firing a plurality of green sheets. The preparation of the support substrate 102A can be performed, for example, in accordance with the production of an LTCC substrate. On the support substrate 102A, form a substrate wiring 8 including vias 8A and lands 8B, 8C. Specifically, for example, after forming holes in the green sheet by punch pressing or carbon dioxide laser or the like, fill the holes with a conductive paste material or perform a printing method or the like to form the vias 8A and lands 8B, 8C. Next, stack a predetermined number of such green sheets and thermocompression bond them to form a green sheet laminate, and by subjecting the green sheet laminate to firing, a support substrate 102A with the substrate wiring 8 formed thereon can be obtained. Note that the substrate wiring 8 can also be formed after firing the green sheet laminate.

[0059] After preparing the support substrate 102A as described above, dispose a solid-state battery 101 on the support substrate 102A. At this time, dispose the solid-state battery 101 on the support substrate 102A such that the substrate wiring 8 of the support substrate 102A and the positive electrode terminal 6 and negative electrode terminal 7 of the solid-state battery 101 are electrically connected to each other. Note that a conductive paste containing silver or the like may be applied on the substrate wiring 8 of the support substrate 102A, and the conductive paste may be electrically connected to the positive electrode terminal 6 and negative electrode terminal 7, respectively.

[0060] Next, form a coating insulating film 102B so as to entirely cover the solid-state battery 101 on the support substrate 102A. When the coating insulating film 102B is made of a resin material, apply the resin material so as to cover the side surface 101C and upper surface 101A of the solid-state battery 101, and then cure the resin material to form the coating insulating film 102B. For example, the coating insulating film 102B may be molded by pressing the resin material using a mold having a predetermined shape. Note that the molding of the coating insulating film 102B is not limited to mold molding, and may be performed using polishing, laser processing, chemical treatment, or the like.

[0061] [[ID=!1]] Next, a coating inorganic film 102C is formed so as to entirely cover the coating insulating film 102B. Specifically, for example, the coating inorganic film 102C may be formed by performing dry plating.

[0062] Through the above-described steps, a battery package 100 can be obtained in which the solid battery 101 placed on the support substrate 102A is entirely covered by the coating insulating film 102B and the coating inorganic film 102C.

[0063] <2.5 Operational Effects> According to the battery package 100 including the solid battery 101 of the present embodiment, the laminate 5 of the solid battery 101 has the solid electrolyte layer 30 made of the solid electrolyte for the solid battery described in the first embodiment. Therefore, since a high ionic conductivity can be obtained in the solid electrolyte layer 30, the solid battery 101 and the battery package 100 having this can achieve more excellent performance such as being capable of coping with rapid charging and obtaining a high output.

[0064] [3. Applications of the Battery Package] Next, the applications (application examples) of the battery package including the above-described solid battery will be described.

[0065] The applications of the battery package are not particularly limited as long as they are mainly machines, devices, instruments, apparatuses, and systems (aggregates of a plurality of devices, etc.) in which the solid battery can be used as a driving power source or a power storage source for power storage. The battery package used as a power source may be a main power source or an auxiliary power source. The main power source is a power source that is preferentially used regardless of the presence or absence of other power sources. The auxiliary power source may be a power source used in place of the main power source or a power source that can be switched from the main power source as necessary. When the battery package is used as an auxiliary power source, the type of the main power source is not limited to those including the solid battery.

[0066] Specific examples of the uses of the battery package are as follows. Electronic devices such as video cameras, digital still cameras, mobile phones, notebook personal computers, cordless telephones, headphone stereos, portable radios, portable TVs, and portable information terminals (including portable electronic devices). Portable household appliances such as electric shavers. Storage devices such as backup power supplies and memory cards. Electric tools such as electric drills and electric saws. A battery pack mounted on a notebook personal computer or the like as a detachable power source. Medical electronic devices such as pacemakers and hearing aids. Electric vehicles such as electric cars (including hybrid cars). A power storage system such as a household battery system that stores power for emergencies. Note that it may be used as a battery module in which a plurality of battery packages are used.

[0067] The battery module is effectively applied to relatively large devices such as electric vehicles, power storage systems, and electric tools. An electric vehicle is a vehicle that operates (runs) using the battery module as a driving power source, and may be an automobile (such as a hybrid car) that also has a driving source other than a battery package equipped with a solid-state battery. A power storage system is a system that uses a battery package as a power storage source. In a household power storage system, since power is stored in a secondary battery that is a power storage source, household electrical appliances and the like can be used using that power.

[0068] [4. Example] The examples of the present disclosure will be described.

[0069] <Example 1> As described below, after manufacturing the solid-state battery 101 shown in FIG. 3, its battery characteristics were evaluated.

[0070] (Fabrication of the positive electrode layer 10) First, an aluminum foil with a thickness of 15 μm was prepared as the positive electrode current collector 11. Next, a positive electrode mixture was obtained by mixing lithium nickel cobalt aluminum oxide (LiNiCoAlO2) as the positive electrode active material, PVDF (polyvinylidene fluoride) as the positive electrode binder, and a conductive aid in which carbon black, acetylene black, and ketjen black were mixed. The mixing ratio of the positive electrode active material, the positive electrode binder, and the conductive aid was set to 95:3:2. Subsequently, the positive electrode mixture was put into NMP (N-methyl-2-pyrrolidone) as an organic solvent, and then the organic solvent into which the positive electrode mixture was put was stirred to prepare a paste-like positive electrode slurry. The stirring was carried out at a rotational speed of 2000 rpm for 3 minutes using a hybrid mixer. Subsequently, after applying the positive electrode slurry to a predetermined region on both sides of the positive electrode current collector 11 using a coating device, the positive electrode slurry was dried to form positive electrode green sheets on both sides of the positive electrode current collector 11. Further, molten Li2(OH)Cl was dropped and impregnated into the prepared positive electrode green sheet as a lithium molten salt. Thus, the positive electrode layer 10 was obtained. 0.9 F 0.1 was dropped and impregnated. Thus, the positive electrode layer 10 was obtained.

[0071] (Fabrication of the negative electrode layer 20) Lithium titanate (Li4Ti5O 12) and a negative electrode binder polyimide were mixed with a conductive aid in which carbon black, acetylene black, and ketjen black were mixed to obtain a negative electrode mixture. The mixing ratio of the negative electrode active material, the negative electrode binder, and the conductive aid was set to 90:5:5. Subsequently, after introducing the negative electrode mixture into NMP (N-methyl-2-pyrrolidone) as an organic solvent, the organic solvent into which the negative electrode mixture was introduced was stirred to prepare a paste-like negative electrode slurry. Stirring was carried out for 3 minutes at a rotational speed of 2000 rpm using a hybrid mixer. Subsequently, using a coating device, after applying the negative electrode slurry onto a release film made of polyethylene terephthalate (PET), the negative electrode slurry was dried to form a green sheet for the negative electrode on the release film. Furthermore, molten Li2(OH)Cl as a lithium molten salt was dropped and impregnated into the prepared green sheet for the negative electrode. Thus, the negative electrode layer 20 was obtained. 0.9 F 0.1 was dropped and impregnated. Thus, the negative electrode layer 20 was obtained.

[0072] (Fabrication of the solid electrolyte layer 30) As the solid electrolyte powder, Li2(OH)Cl having an inverse perovskite structure with a lattice constant of 3.91 Å, as the non-lithium compound powder, Al2O3, and an organic binder were kneaded to prepare a kneaded powder. Next, by the hot isostatic pressing (HIP) method, while heating the kneaded powder, it was compression-molded to produce a compression-molded body. At that time, it was compression-molded while heating at 270 °C which is lower than 292 °C at which Li2(OH)Cl melts. Thus, the solid electrolyte layer 30 was obtained.

[0073] (Fabrication of the laminate 5) Subsequently, the positive electrode layer 10, the solid electrolyte layer 30, the negative electrode layer 20, and the solid electrolyte layer 30, which were each fabricated as described above, were laminated in order to form a laminated structure. The laminated structure was fired at a temperature of 270 °C for 1 hour in a nitrogen atmosphere while being fixed under pressure at 0.5 MPa using a jig to obtain the laminate 5.

[0074] Next, a positive electrode terminal 6 was formed by applying a conductive paste to the side surface of the laminate 5 where a part of the positive electrode layer 10 was exposed. A negative electrode terminal 7 was formed by applying a conductive paste to the side surface of the laminate 5 where a part of the negative electrode layer 20 was exposed.

[0075] Thus, the solid-state battery 101 was obtained.

[0076] (Evaluation of Battery Characteristics) When the battery characteristics of the solid-state battery 101 were evaluated, the results shown in Table 1 were obtained. Here, the ionic conductivity [S / cm] of the solid electrolyte layer 30 at 90 °C was evaluated. Specifically, using an alternating current impedance measuring device (manufactured by Solartron, 1260A), the ionic conductivity [S / cm] was measured at a frequency range of 100 mHz to 1 MHz and an alternating current amplitude voltage of 100 mV.

[0077]

Table 1

[0078] <Example 2> As shown in Table 1, a solid-state battery 101 was fabricated in the same manner as in Example 1, except that ZrO2 was used as the non-lithium compound powder when fabricating the solid electrolyte layer 30. Then, the battery characteristics were evaluated in the same manner as in Example 1. The results are shown together in Table 1.

[0079] = <Example 3> As shown in Table 1, a solid-state battery 101 was fabricated in the same manner as in Example 1, except that TiO2 was used as the non-lithium compound powder when fabricating the solid electrolyte layer 30. Then, the battery characteristics were evaluated in the same manner as in Example 1. The results are shown together in Table 1.

[0080] <Example 4> As shown in Table 1, when fabricating the solid electrolyte layer 30, Li2(OH)Cl was used as the solid electrolyte powder 0.9 F 0.1A solid battery 101 was fabricated in the same manner as in Example 1, except that [the method] was changed to use [a certain material], and then the battery characteristics were evaluated in the same manner as in Example 1. The results are shown together with those in Table 1.

[0081] <Example 5> As shown in Table 1, a solid battery 101 was fabricated in the same manner as in Example 1, except that Li3OCl was used as the solid electrolyte powder when fabricating the solid electrolyte layer 30, and then the battery characteristics were evaluated in the same manner as in Example 1. The results are shown together with those in Table 1.

[0082] <Example 6> As shown in Table 1, when fabricating the solid electrolyte layer 30, Li2(OH)Cl 0.9 F 0.1 was used and MgO was used as the non-lithium compound powder. A solid battery 101 was fabricated in the same manner as in Example 1, except for this, and then the battery characteristics were evaluated in the same manner as in Example 1. The results are shown together with those in Table 1.

[0083] <Example 7> As shown in Table 1, when fabricating the solid electrolyte layer 30, Li2(OH)Cl 0.9 F 0.1 was used and AlN was used as the non-lithium compound powder. A solid battery 101 was fabricated in the same manner as in Example 1, except for this, and then the battery characteristics were evaluated in the same manner as in Example 1. The results are shown together with those in Table 1.

[0084] <Comparative Example 1> As shown in Table 1, a solid battery 101 was fabricated in the same manner as in Example 1, except that the non-lithium compound powder was not kneaded when fabricating the solid electrolyte layer 30, and then the battery characteristics were evaluated in the same manner as in Example 1. The results are shown together with those in Table 1. shown as follows.

[0085] <Comparative Example 2> As shown in Table 1, when fabricating the solid electrolyte layer 30, Li2(OH)Cl was used as the solid electrolyte powder and non-lithium compound powder was not kneaded. Except for these matters, after fabricating the solid-state battery 101 in the same manner as in Example 1, the battery characteristics were evaluated in the same manner as in Example 1. The results are shown together with Table 1. 0.9 F 0.1 Using this, and not kneading non-lithium compound powder, a solid-state battery 101 was fabricated in the same manner as in Example 1, except for these matters. Then, the battery characteristics were evaluated in the same manner as in Example 1. The results are shown together with Table 1.

[0086] <Comparative Example 3> As shown in Table 1, when fabricating the solid electrolyte layer 30, LiOCl was used as the solid electrolyte powder and non-lithium compound powder was not kneaded. Except for these matters, after fabricating the solid-state battery 101 in the same manner as in Example 1, the battery characteristics were evaluated in the same manner as in Example 1. The results are shown together with Table 1.

[0087] <Comparative Example 4> As shown in Table 1, when fabricating the solid electrolyte layer 30, instead of non-lithium compound powder, Li 1.07 Al 0.69 Ti 1.46 (PO4)3 was kneaded. Except for this, after fabricating the solid-state battery 101 in the same manner as in Example 1, the battery characteristics were evaluated in the same manner as in Example 1. The results are shown together with Table 1.

[0088] <Comparative Example 5> As shown in Table 1, when fabricating the solid electrolyte layer 30, instead of non-lithium compound powder, Li3PO4, a lithium compound, was kneaded. Except for this, after fabricating the solid-state battery 101 in the same manner as in Example 1, the battery characteristics were evaluated in the same manner as in Example 1. The results are shown together with Table 1.

[0089] [Discussion] As shown in Table 1, in Examples 1 to 3 using a solid electrolyte layer having Li2(OH)Cl as a solid electrolyte and a non-Li compound, the ionic conductivity at 90 °C showed a higher value than that in Comparative Example 1 using a solid electrolyte layer having only Li2(OH)Cl as a solid electrolyte. Also, in Examples 1 to 3, the ionic conductivity at 90 °C showed a higher value than that in Comparative Examples 4 and 5 using a solid electrolyte layer having Li2(OH)Cl as a solid electrolyte and a Li compound. Also, Li2(OH)Cl 0.9 F 0.1 In Examples 4, 6, and 7 using a solid electrolyte layer having Li2(OH)Cl 0.9 F 0.1 and a non-Li compound, the ionic conductivity at 90 °C showed a higher value than that in Comparative Example 2 using a solid electrolyte layer having only Li2(OH)Cl as a solid electrolyte. Further, in Example 5 using a solid electrolyte layer having Li3OCl as a solid electrolyte and a non-Li compound, the ionic conductivity at 90 °C showed a higher value than that in Comparative Example 3 using a solid electrolyte layer having only Li3OCl as a solid electrolyte.

[0090] From the above results, it was confirmed that in the solid electrolyte for a solid battery of the present disclosure, good ionic conductivity can be obtained by combining a lithium salt solid electrolyte portion and a non-lithium compound portion containing no lithium.

[0091] As described above, the present disclosure has been described with some embodiments, modifications, and examples, but the configuration of the present disclosure is not limited to the configuration of the above description and can be variously modified.

[0092] Specifically, for example, in the first embodiment, the battery package 100 in which the solid battery 101 is placed on the support substrate 102A and packaged was described, but the battery package of the present disclosure is not limited to this mode. For example, it may be a mode in which there is no support substrate and it is sealed only by a coating insulating film, a coating inorganic film, or the like.

[0093] In addition, in the above-described first embodiment, the case where the electrode reactant is lithium has been described. However, the electrode reactant is not particularly limited. Therefore, as described above, the electrode reactant may be another alkali metal such as sodium and potassium, or an alkaline earth metal such as beryllium, magnesium, and calcium. In addition, the electrode reactant may be another light metal such as aluminum.

[0094] The effects described in this specification are merely examples, and the effects of the present disclosure are not limited to the effects described in this specification. Therefore, other effects may be obtained with respect to the present disclosure.

Claims

1. A lithium salt solid electrolyte portion, and a non-lithium compound portion embedded in the lithium salt solid electrolyte portion are provided, wherein the lithium salt solid electrolyte portion contains at least one of Li₂(OH)Cl and Li₂(OH)Cl₀.₉F₀.₁ A solid electrolyte for a solid battery.

2. The lithium salt solid electrolyte portion has a melting point of 400 °C or lower The solid electrolyte for a solid battery according to Claim 1.

3. The lithium salt solid electrolyte portion has an inverse perovskite structure The solid electrolyte for a solid battery according to Claim 1 or Claim 2.

4. The non-lithium compound portion is made of an inorganic insulating material The solid electrolyte for a solid battery according to Claim 1 or Claim 2.

5. The inorganic insulating material is a metal oxide or a metal nitride The solid electrolyte for a solid battery according to Claim 4.

6. The inorganic insulating material is Al ２ O ３ , ZrO ２ , or TiO ２ is. The solid electrolyte for a solid battery according to Claim 4.

7. The median diameter D50 of the non-lithium compound portion is 5 nm or more and 5 μm or less The solid electrolyte for a solid battery according to Claim 1 or Claim 2.

8. A positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode are provided, wherein the solid electrolyte layer has a lithium salt solid electrolyte portion, and a non-lithium compound portion embedded in the lithium salt solid electrolyte portion and, the lithium salt solid electrolyte portion contains at least one of Li₂(OH)Cl and Li₂(OH)Cl₀.₉F₀.₁ A solid battery.

9. A solid battery, and a covering portion covering the solid battery are provided, wherein the solid battery has a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode and, the solid electrolyte layer has a lithium salt solid electrolyte portion, and a non-lithium compound portion embedded in the lithium salt solid electrolyte portion and, the lithium salt solid electrolyte portion contains at least one of Li₂(OH)Cl and Li₂(OH)Cl₀.₉F₀.₁ A battery package.

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