Solid-state batteries and electronic devices

Abstract

The present invention provides a solid-state battery and an electronic device, each of which is capable of relaxing a stress based on a volume change. This solid-state battery is provided with: a plurality of solid-state battery elements 141, each of which is obtained by stacking a positive electrode layer 110, a negative electrode layer 120, and a solid electrolyte layer 130 that is interposed between the positive electrode layer 110 and the negative electrode layer 120; and an interlayer conduction layer 170 which is positioned between the solid-state battery elements 141. The interlayer conduction layer 170 is sandwiched between the positive electrode layer 110 or the negative electrode layer 120 of one solid-state battery element 141 and the positive electrode layer 110 or the negative electrode layer 120 of another solid-state battery element 141; the positive electrode layer 110 or the negative electrode layer 120 with which the interlayer conduction layer 170 is sandwiched contains a solid electrolyte; the solid electrolyte ratio of the positive electrode layer 110 or the negative electrode layer 120 with which the interlayer conduction layer 170 is sandwiched is 40% by weight to 60% by weight based on the total weight of the positive electrode layer 110 or the negative electrode layer 120; and the solid electrolyte ratio of the interlayer conduction layer 170 is 10% by weight to 35% by weight based on the total weight of the interlayer conduction layer 170.

Description

[Technical Field]

[0001] The present disclosure relates to solid-state batteries and electronic devices. [Background technology]

[0002] Secondary batteries, which can be repeatedly charged and discharged, have been used for a variety of purposes. For example, secondary batteries are used as power sources for electronic devices such as smartphones and laptop computers.

[0003] In secondary batteries, a liquid electrolyte is generally used as a medium for ion migration that contributes to charging and discharging. In other words, a so-called electrolytic solution is used in secondary batteries. However, in such secondary batteries, safety is generally required to prevent leakage of the electrolytic solution. In addition, organic solvents and the like used in the electrolytic solution are flammable, so safety is also required in this respect.

[0004] Therefore, research is being conducted on solid-state batteries that use solid electrolytes instead of liquid electrolytes. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-166020 Summary of the Invention [Problem to be solved by the invention]

[0006] It is generally known that a volume change occurs in the positive or negative electrode during charging and discharging of a battery, and the stress caused by the volume change may cause the battery to break. Various countermeasures against the battery breakage have been investigated.

[0007] For example, Patent Document 1 discloses a configuration in which the interfaces between the positive electrode layer and the solid electrolyte layer, and between the negative electrode layer and the solid electrolyte, are intertwined with each other, as an all-solid-state battery that is free from cracks, warping, or cracks or peeling between layers. According to Patent Document 1, by increasing the adhesive strength between each layer, cracks, warping, and cracks or peeling between each layer are less likely to occur (see paragraph

[0022] of Patent Document 1).

[0008] However, the all-solid-state battery described in Patent Document 1 does not have a structure that releases (mitigates) stress caused by volume changes, and there is a risk that the battery may break due to accumulated stress.

[0009] The present disclosure has been made in view of the above-mentioned problems. That is, a main object of the present disclosure is to provide a solid-state battery and an electronic device that can relieve stress caused by volume change. [Means for solving the problem]

[0010] The inventors of the present invention attempted to solve the above problems by taking a new approach rather than simply extending the conventional technology, and as a result, they have developed a solid-state battery that achieves the above-mentioned main objective.

[0011] The solid-state battery according to the present disclosure comprises: a plurality of solid-state battery elements each including a stack of a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer; an interlayer conductive layer located between each of the solid-state battery elements; the interlayer conductive layer is sandwiched between a positive electrode layer or a negative electrode layer of one solid-state battery element and a positive electrode layer or a negative electrode layer of the other solid-state battery element, the positive electrode layer or the negative electrode layer sandwiching the interlayer conductive layer contains a solid electrolyte, The solid electrolyte ratio of the positive electrode layer or the negative electrode layer sandwiching the interlayer conductive layer is 40 wt % or more and 60 wt % or less based on the total weight of the positive electrode layer or the negative electrode layer, The solid electrolyte ratio in the interlayer conductive layer is 10% by weight or more and 35% by weight or less based on the entire interlayer conductive layer.

[0012] Furthermore, the electronic device according to the present disclosure has the above-described solid-state battery surface-mounted. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to provide a solid-state battery and an electronic device that can relieve stress caused by volume change. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view of a main portion of a solid-state battery according to the present disclosure. [Figure 2] FIG. 10 is a cross-sectional view of a main part of a modified example of the solid state battery of the present disclosure. [Figure 3] FIG. 10 is a cross-sectional view of a main part of a modified example of the solid state battery of the present disclosure. [Figure 4] FIG. 1 is a cross-sectional view of a solid-state battery according to the present disclosure. [Figure 5] 1A to 1C are cross-sectional views illustrating steps in the manufacturing process of a solid-state battery according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] The "solid-state battery" and the "electronic device" having the surface-mounted solid-state battery of the present disclosure will be described in detail below. While the description will be made with reference to the drawings as needed, the contents shown in the drawings are merely shown as schematic examples for the purpose of understanding the present disclosure, and the appearance and dimensional ratios may differ from the actual product.

[0016] First, a "solid-state battery" according to an embodiment of the present disclosure will be described. In the present disclosure, the term "solid-state battery" broadly refers to a battery whose components are made of solids, and in the narrow sense refers to an all-solid-state battery whose battery components (particularly preferably all battery components) are made of solids. In a preferred embodiment, the solid-state battery according to the present disclosure is a stacked solid-state battery in which each layer constituting a battery unit is stacked on top of each other, and preferably each such layer may be a fired body. Note that the term "solid-state battery" encompasses not only so-called "secondary batteries" that can be repeatedly charged and discharged, but also "primary batteries" that can only be discharged. According to a preferred embodiment of the present disclosure, the "solid-state battery" is a secondary battery. The term "secondary battery" should not be overly constrained by its name, and may also encompass, for example, an electricity storage device.

[0017] As used herein, a "planar view" refers to a view of an object viewed from above or below along the thickness direction of the layers constituting the solid-state battery. Furthermore, a "cross-sectional view" refers to a view of an object viewed from a direction substantially perpendicular to the thickness direction of the layers constituting the solid-state battery (in other words, a view of an object cut along a plane parallel to the thickness direction). The terms "vertical direction" and "horizontal direction" used directly or indirectly in this specification correspond to the vertical direction and horizontal direction in the drawings, respectively. Unless otherwise specified, the same reference numerals or symbols refer to the same components or parts or have the same meaning. In a preferred embodiment, the vertical downward direction (i.e., the direction in which gravity acts) can be considered to correspond to the "downward direction," and the opposite direction can be considered to correspond to the "upward direction." Furthermore, references to directions or orientations in this specification are provided solely for convenience and are not intended to limit the scope of the present disclosure unless otherwise explicitly stated. For example, relative terms such as "outside" and "inside" and their derivatives should be understood to refer to the direction as described or illustrated. In other words, unless otherwise explicitly stated, the invention is not necessarily limited to a specific direction, orientation, or form. Similarly, terms such as "provided" and "disposed" and their derivatives may refer to a form in which other elements, such as intervening elements, are present, rather than a direct form, unless otherwise explicitly stated.

[0018] [Solid-state battery configuration] The solid-state battery 100 (see FIGS. 1 to 4) has a laminate 140 including solid-state battery elements 141 each including a battery constituent unit made up of a positive electrode layer 110, a negative electrode layer 120, and at least a solid electrolyte layer 130 interposed therebetween, and an interlayer conductive layer 170 located between each solid-state battery element 141. The interlayer conductive layer 170 is sandwiched between the positive electrode layer 110 or the negative electrode layer 120 of one solid-state battery element 141 and the positive electrode layer 110 or the negative electrode layer 120 of the other solid-state battery element 141. The positive electrode layer 110 or the negative electrode layer 120 sandwiching the interlayer conductive layer 170 contains a solid electrolyte, and the solid electrolyte ratio of the positive electrode layer 110 or the negative electrode layer 120 sandwiching the interlayer conductive layer 170 is 40% by weight or more and 60% by weight or less based on the layer containing the solid electrolyte, and the solid electrolyte ratio of the interlayer conductive layer 170 is 10% by weight or more and 35% by weight or less based on the layer containing the solid electrolyte.

[0019] According to the solid-state battery 100 of the present disclosure, the solid electrolyte ratio of the interlayer conductive layer 170 is smaller than the solid electrolyte ratio of the positive electrode layer 110 or the negative electrode layer 120 that sandwiches the interlayer conductive layer 170. Here, a small solid electrolyte ratio reduces the strength of the layer structure. Therefore, the strength of the interlayer conductive layer 170 is relatively lower than the strength of the positive electrode layer 110 or the negative electrode layer 120 that sandwiches the interlayer conductive layer 170. Therefore, when stress accumulates inside the solid-state battery, the stress can be concentrated in the interlayer conductive layer 170, which has low strength. As an example, stress can be relieved by generating cracks in the interlayer conductive layer 170.

[0020] Furthermore, the interlayer conductive layer 170 contributes less to the solid-state battery characteristics than the solid-state battery element 141. Therefore, even if stress is concentrated on the interlayer conductive layer 170 and a load is applied, causing a crack, the effect on the solid-state battery characteristics is small. In other words, by applying a load to the interlayer conductive layer 170 side, it is possible to reduce the load on the solid-state battery element 141 side, thereby preventing the deterioration of the solid-state battery characteristics.

[0021] Furthermore, by setting the solid electrolyte ratio of the positive electrode layer 110 or the negative electrode layer 120 sandwiching the interlayer conductive layer 170 and the solid electrolyte ratio of the interlayer conductive layer 170 within the above numerical range, it is possible to maintain the productivity of the solid battery. The solid battery of the present disclosure will be described in detail below.

[0022] 1. Solid-state battery elements The solid-state battery element 141 is a battery structural unit composed of a positive electrode layer 110, a negative electrode layer 120, and at least a solid electrolyte layer 130 interposed therebetween. A plurality of these solid-state battery elements 141 may be stacked with an interlayer conductive layer 170 interposed therebetween. As an example, in FIG. 1, two solid-state battery elements 141 may be stacked with an interlayer conductive layer 170 interposed therebetween. As another example, in FIG. 3, four solid-state battery elements 141 may be stacked with an interlayer conductive layer 170 interposed therebetween. More specifically, the plurality of solid-state battery elements 141 may be electrically connected in parallel with each other. Desired battery characteristics can be obtained by electrically connecting the plurality of solid-state battery elements in parallel.

[0023] Each layer of the solid-state battery element 141 may be formed by firing. That is, the positive electrode layer 110, the negative electrode layer 120, the solid electrolyte layer 130, etc. may form a sintered layer. Preferably, the positive electrode layer 110, the negative electrode layer 120, and the solid electrolyte layer 130 may be integrally fired together to form a sintered body. More preferably, a laminate 140 in which interlayer conductive layers 170 are interposed between a plurality of solid-state battery elements 141 may be integrally sintered to form an integral sintered body. In this specification, the direction in which the positive electrode layers and the negative electrode layers are stacked (vertical direction) is referred to as the "stacking direction," and the direction intersecting with the stacking direction is the horizontal direction in which the positive electrode layers and the negative electrode layers extend.

[0024] 1-1. Positive electrode layer and negative electrode layer The positive electrode layer 110 may be an electrode layer including at least a positive electrode active material layer 111 and a positive electrode current collector layer 112. In a preferred embodiment, the positive electrode active material layer 111 may be composed of a sintered body including at least positive electrode active material particles and solid electrolyte particles. The positive electrode current collector layer 112 may further include a solid electrolyte. On the other hand, the negative electrode layer 120 may be an electrode layer including at least a negative electrode active material layer 121 and a negative electrode current collector layer 122. In a preferred embodiment, the negative electrode active material layer 121 may be composed of a sintered body including at least negative electrode active material particles and solid electrolyte particles. The negative electrode current collector layer 122 may further include a solid electrolyte.

[0025] Here, the positive electrode active material and the negative electrode active material are substances involved in the exchange of electrons in a solid-state battery. Charging and discharging are performed by the movement (or conduction) of ions between the positive electrode layer and the negative electrode layer via the solid electrolyte, and the exchange of electrons between the positive electrode layer and the negative electrode layer via external terminals.

[0026] The illustrated examples (FIGS. 1 to 3) illustrate a configuration in which a positive electrode layer 110 is formed by laminating one positive electrode active material layer 111 and one positive electrode current collector layer 112, and a negative electrode layer 120 is formed by laminating one negative electrode active material layer 121 and one negative electrode current collector layer 122, per solid-state battery element 141. However, the number of layers is not limited to this example, and two or more active material layers and current collector layers may be used. The film thickness of the positive electrode layer 110 or the negative electrode layer 120 may be 5 μm or more and 60 μm or less, preferably 8 μm or more and 50 μm or less. Alternatively, it may be 5 μm or more and 30 μm or less.

[0027] (Cathode active material layer) The positive electrode active material contained in the positive electrode active material layer 111 may be, for example, a lithium-containing compound or a sodium-containing compound. In other words, it may be capable of absorbing and releasing lithium ions or sodium ions. The type of lithium-containing compound is not particularly limited, and may be, for example, a lithium transition metal composite oxide and / or a lithium transition metal phosphate compound. Lithium transition metal composite oxide is a general term for oxides containing lithium and one or more transition metal elements as constituent elements. Lithium transition metal phosphate compound is a general term for phosphate compounds containing lithium and one or more transition metal elements as constituent elements. The type of transition metal element is not particularly limited, and may be, for example, cobalt (Co), nickel (Ni), manganese (Mn), and / or iron (Fe).

[0028] The lithium transition metal composite oxide is, for example, Li x M1O2 and Li y Lithium transition metal phosphate compounds include compounds represented by the formula: Li z The compounds are represented by the formula M3PO4, where M1, M2, and M3 each represent one or more transition metal elements, and the values ​​of x, y, and z are arbitrary.

[0029] Specifically, the lithium transition metal composite oxide is, for example, LiCoO2, LiNiO2, LiVO2, LiCrO2, LiMn2O4, LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O2, and LiNi 0.5 Mn 1.5O4, etc. Examples of lithium transition metal phosphate compounds include LiFePO4, LiCoPO4, and LiMnPO4. Lithium transition metal composite oxides (particularly LiCoO2) may contain trace amounts (of the order of a few percent) of additive elements. Examples of additive elements include one or more elements selected from the group consisting of aluminum (Al), magnesium (Mg), nickel (Ni), manganese (Mn), titanium (Ti), boron (B), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), tungsten (W), zirconium (Zr), yttrium (Y), niobium (Nb), calcium (Ca), strontium (Sr), bismuth (Bi), sodium (Na), potassium (K), and silicon (Si).

[0030] In addition, the positive electrode active material capable of absorbing and releasing sodium ions may be at least one selected from the group consisting of sodium-containing phosphate compounds having a Nasicon structure, sodium-containing phosphate compounds having an olivine structure, sodium-containing layered oxides, and sodium-containing oxides having a spinel structure. For example, in the case of sodium-containing phosphate compounds, at least one selected from the group consisting of Na3V2(PO4)3, NaCoFe2(PO4)3, Na2Ni2Fe(PO4)3, Na3Fe2(PO4)3, Na2FeP2O7, Na4Fe3(PO4)2(PO2O7), and as a sodium-containing layered oxide, NaFeO2 may be used.

[0031] Alternatively, the positive electrode active material may be, for example, an oxide, a disulfide, a chalcogenide, or a conductive polymer. The oxide may be, for example, titanium oxide, vanadium oxide, or manganese dioxide. The disulfide may be, for example, titanium disulfide or molybdenum sulfide. The chalcogenide may be, for example, niobium selenide. The conductive polymer may be, for example, a disulfide, polypyrrole, polyaniline, polythiophene, polyparastyrene, polyacetylene, or polyacene.

[0032] The content of the positive electrode active material in the positive electrode active material layer 111 is usually 50% by weight or more, for example 60% by weight or more, relative to the total amount of the positive electrode active material layer 111. The positive electrode active material layer 111 may contain two or more types of positive electrode active materials, in which case the total content thereof may be within the above range. When the content of the active material is 50% by weight or more, the energy density of the battery can be particularly increased.

[0033] (Negative electrode active material layer) The negative electrode active material contained in the negative electrode active material layer 121 is, for example, a carbon material, a metal-based material, a lithium alloy and / or a lithium-containing compound.

[0034] Specifically, the carbon material is, for example, graphite, graphitizable carbon, non-graphitizable carbon, mesocarbon microbeads (MCMB) and / or highly oriented graphite (HOPG).

[0035] Metallic materials are a general term for materials containing, as constituent elements, one or more of metal elements and semimetal elements that can form an alloy with lithium. This metallic material may be a simple substance, an alloy, or a compound. The purity of the simple substance described here is not necessarily limited to 100%, and the simple substance may contain trace amounts of impurities.

[0036] Metal elements and metalloid elements include, for example, silicon (Si), tin (Sn), aluminum (Al), indium (In), magnesium (Mg), boron (B), gallium (Ga), germanium (Ge), lead (Pb), bismuth (Bi), cadmium (Cd), titanium (Ti), chromium (Cr), iron (Fe), niobium (Nb), molybdenum (Mo), silver (Ag), zinc (Zn), hafnium (Hf), zirconium (Zr), yttrium (Y), palladium (Pd) and / or platinum (Pt).

[0037] Specifically, the metal-based material may be, for example, Si, Sn, SiB4, TiSi2, SiC, Si3N4, or SiO v (0 <v≦2)、LiSiO、SnOw (0 <w≦2)、SnSiO3、LiSnOおよび / またはMg2Snなどである。

[0038] The lithium-containing compound is, for example, a lithium transition metal composite oxide. The definition of the lithium transition metal composite oxide is as described above. Specifically, the lithium transition metal composite oxide is, for example, Li3V2(PO4)3, Li3Fe2(PO4)3, Li4Ti5O 12 , LiTi2(PO4)3, and / or LiCuPO4.

[0039] In addition, the negative electrode active material capable of absorbing and releasing sodium ions may be at least one selected from the group consisting of sodium-containing phosphate compounds having a Nasicon structure, sodium-containing phosphate compounds having an olivine structure, and sodium-containing oxides having a spinel structure.

[0040] The content of the negative electrode active material in the negative electrode active material layer 121 is usually 50% by weight or more, for example 60% by weight or more, relative to the total amount of the negative electrode active material portion. The negative electrode active material portion may contain two or more types of negative electrode active materials, in which case the total content thereof may be within the above range. By making the content of the active material 50% by weight or more, the energy density of the battery can be particularly increased.

[0041] In a preferred embodiment of the active material layer, the positive electrode active material layer 111 and / or the negative electrode active material layer 121 may contain a conductive material. Examples of the conductive material contained in the positive electrode active material layer 111 and / or the negative electrode active material layer 121 include carbon materials and metal materials. Specific examples of the carbon materials include graphite and carbon nanotubes. Examples of the metal materials include copper (Cu), magnesium (Mg), titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), indium (In), gold (Au), platinum (Pt), silver (Ag), and / or palladium (Pd), and may also be alloys of two or more of these metals.

[0042] The positive electrode active material layer 111 and / or the negative electrode active material layer 121 may contain a binder. The binder may be, for example, one or more of synthetic rubber and polymeric materials. Specifically, the synthetic rubber may be, for example, styrene-butadiene rubber, fluorine-containing rubber, and / or ethylene propylene diene. The polymeric material may be, for example, at least one selected from the group consisting of polyvinylidene fluoride, polyimide, and acrylic resin.

[0043] The positive electrode active material layer 111 and / or the negative electrode active material layer 121 may contain a sintering aid, which may be at least one selected from the group consisting of lithium oxide, sodium oxide, potassium oxide, boron oxide, silicon oxide, bismuth oxide, and phosphorus oxide.

[0044] The thickness of each of the positive electrode active material layer 111 and the negative electrode active material layer 121 is not particularly limited, and may be, for example, independently 2 μm or more and 100 μm or less, and particularly 5 μm or more and 50 μm or less.

[0045] Furthermore, the positive electrode active material layer 111 or the negative electrode active material layer 121 located on both sides of the interlayer conductive layer 170 (described later) may be arranged more inward than the opposing active material layer of the counter electrode. Specifically, in the illustrated example ( FIG. 1 ), the positive electrode active material layer 111 may be arranged more inward than the opposing negative electrode active material layer 121. This arrangement is due to the fact that if there is a positive electrode portion that does not face the negative electrode, dendrites may form on the negative electrode side, causing a short circuit. Furthermore, in the solid-state battery of the present disclosure, compressive stress is applied during charge and discharge in region A where the opposing active material layers face each other, and tensile stress is applied during charge and discharge in region B where the opposing active material layers do not face each other. However, the stress can be appropriately alleviated by the interlayer conductive layer 170 (described later).

[0046] (Positive electrode current collector layer and negative electrode current collector layer) The positive electrode current collector layer 112 and the negative electrode current collector layer 122 preferably have higher electronic conductivity than the positive electrode active material layer 111 and the negative electrode active material layer 121. In other words, the positive electrode current collector layer 112 and the negative electrode current collector layer 122 are used to collect current between the positive electrode layers 110 or between the negative electrode layers 120. As specific constituent materials, the positive electrode current collector layer 112 and the negative electrode current collector layer 122 may contain a conductive material and a solid electrolyte.

[0047] The conductive material used for the positive electrode current collector layer 112 may be, for example, at least one selected from the group consisting of carbon materials, silver, palladium, gold, platinum, aluminum, copper, nickel-lithium transition metal composite oxides, and lithium-transition metal phosphate compounds.

[0048] The conductive material used for the negative electrode current collector layer 122 may be at least one selected from the group consisting of carbon materials, silver, palladium, gold, platinum, aluminum, copper, and nickel.

[0049] Specific materials for the solid electrolyte will be described in detail in "1-2. Solid electrolyte layer" below.

[0050] The solid electrolyte ratio is 40% by weight or more and 60% by weight or less based on the total weight of the positive electrode current collector layer 112 or the negative electrode current collector layer 122. In the present disclosure, the positive electrode current collector layer 112 and the negative electrode current collector layer 122 are composed of a conductive material and a solid electrolyte. Therefore, if the solid electrolyte ratio in the current collector layer is 40% by weight based on the total weight, the conductive material is 60% by weight. If the solid electrolyte ratio in the current collector layer is 60% by weight based on the total weight, the conductive material is 40% by weight. Satisfying this numerical range can increase the strength of the positive electrode current collector layer 112 and the negative electrode current collector layer 122. Therefore, even if stress accumulates inside the solid-state battery, breakage of the positive electrode current collector layer 112 and the negative electrode current collector layer 122 can be reduced. Details of the numerical range of the solid electrolyte ratio will be described in detail in the "Examples" section below.

[0051] The positive electrode current collector layer 112 and / or the negative electrode current collector layer 122 may be in the form of a sintered body. That is, they may be composed of a sintered body containing an active material, a binder, and / or a sintering aid in addition to the conductive material and solid electrolyte described above. Furthermore, the positive electrode current collector layer 112 and / or the negative electrode current collector layer 122 may contain a heat-resistant resin. When the current collector layer contains a heat-resistant resin, cracks caused by expansion of the current collector layer can be suppressed.

[0052] There are no particular limitations on the thickness of each of the positive electrode current collector layer 112 and the negative electrode current collector layer 122, and for example, each may independently be 1 μm or more and 100 μm or less, and particularly 1 μm or more and 50 μm or less.

[0053] In a preferred embodiment of the positive electrode current collector layer 112 and the negative electrode current collector layer 122, the positive electrode current collector layer 112 or the negative electrode current collector layer 122 sandwiching the interlayer conductive layer 170 may be exposed from the positive electrode active material layer 111 or the negative electrode active material layer 121 located on both sides of the interlayer conductive layer 170. As used herein, the phrase "an embodiment in which the current collector layers sandwiching the interlayer conductive layer are exposed from the active material layers located on both sides of the interlayer conductive layer" refers to an embodiment in which the current collector layers sandwiching the interlayer conductive layer are exposed to the active material layers located on both sides of the interlayer conductive layer. In other words, this refers to an embodiment in which the current collector layers sandwiching the interlayer conductive layer are exposed because the length of the current collector layers sandwiching the interlayer conductive layer is longer than the active material layers located on both sides of the interlayer conductive layer. In the illustrated example (FIG. 1), the positive electrode current collector layer 112 extends so as to be exposed from the solid battery element 141, but the positive electrode active material layer 111 does not have to extend so as to be exposed from the solid battery element 141. With this configuration, the positive electrode current collector layer 112 and the negative electrode current collector layer 122 exposed from the solid battery element 141 can be appropriately wired to the terminal electrodes 151, 152. In addition, the positive electrode active material layer 111 or the negative electrode active material layer 121 involved in the exchange of electrons can be appropriately protected without being exposed.

[0054] 1-2.Solid electrolyte layer The solid electrolyte constituting the solid electrolyte layer 130 is a material capable of conducting lithium ions or sodium ions. In particular, the solid electrolyte constituting the battery constituent unit in a solid-state battery forms a layer capable of conducting lithium ions or sodium ions between the positive electrode layer 110 and the negative electrode layer 120. It is sufficient that the solid electrolyte layer is provided at least between the positive electrode layer 110 and the negative electrode layer 120. Specific examples of the solid electrolyte contained in the solid electrolyte layer include one or more of a crystalline solid electrolyte, a glass-based solid electrolyte, and a glass-ceramic-based solid electrolyte.

[0055] Crystalline solid electrolytes include, for example, oxide-based crystalline materials and sulfide-based crystalline materials. Examples of oxide-based crystalline materials include lithium-containing phosphate compounds having a Nasicon structure, oxides having a perovskite structure, oxides having a garnet or garnet-like structure, and oxide glass ceramic-based lithium ion conductors. Examples of lithium-containing phosphate compounds having a Nasicon structure include Li x M y (PO4)3 (1≦x≦2, 1≦y≦2, M is at least one selected from the group consisting of titanium (Ti), germanium (Ge), aluminum (Al), gallium (Ga) and zirconium (Zr)). An example of a lithium-containing phosphate compound having a Nasicon structure is, for example, Li 1.2 Al 0.2 Ti 1.8 (PO4)3, etc. An example of an oxide with a perovskite structure is La 0.55 Li 0.35 Examples of oxides with garnet or garnet-like structures include Li7La3Zr2O 12 Examples of sulfide-based crystal materials include thio-LISICON, for example, Li 3.25 Ge 0.25 P 0.75 S4 and Li 10 GeP2S 12 The crystalline solid electrolyte may include a polymer material (for example, polyethylene oxide (PEO)).

[0056] Examples of glass-based solid electrolytes include oxide-based glass materials and sulfide-based glass materials, such as Li2O-SiO2, Li2O-Al2O3-TiO2-P2O5, 54Li2O·11SiO2·35B2O3, 50Li4SiO4·50Li3BO3, 23.3Li2O-76.7GeO2, and / or 60Li2O-40P2O. 5、 In other words, the oxide-based glass material may contain at least one element selected from the group consisting of lithium, silicon, and boron. The oxide-based glass material essentially contains lithium oxide and may contain at least one element selected from the group consisting of germanium oxide, silicon oxide, boron oxide, and phosphorus oxide. Examples of sulfide-based glass materials include 30Li2S·26B2S3·44LiI, 63Li2S·36SiS2·1Li3PO4, 57Li2S·38SiS2·5Li4SiO4, 70Li2S·30P2S5, and / or 50Li2S·50GeS2.

[0057] The glass ceramic solid electrolyte is, for example, an oxide-based glass ceramic material or a sulfide-based glass ceramic material. As the oxide-based glass ceramic material, for example, a phosphate compound containing lithium, aluminum, and titanium as constituent elements (LATP) or a phosphate compound containing lithium, aluminum, and germanium as constituent elements (LAGP) can be used. LATP is, for example, Li 1.07 Al 0.69 Ti 1.46 (PO4)3, etc. Also, LAGP is, for example, Li 1.5 Al 0.5 Ge 1.5(PO4), etc. In other words, the oxide-based glass ceramic material may contain at least one selected from the group consisting of lithium, silicon, and boron. For example, 90Li3BO3-10Li2SO4 may be mentioned. Furthermore, the oxide-based glass ceramic material essentially contains lithium oxide, and may contain at least one selected from the group consisting of germanium oxide, silicon oxide, boron oxide, and phosphorus oxide. Furthermore, the sulfide-based glass ceramic material may be, for example, Li7P3S 11 and Li 3.25 P 0.95 Examples include S4.

[0058] When emphasis is placed on the viewpoint of excellent atmospheric stability and ease of integral sintering, the solid electrolyte may contain at least one material selected from the group consisting of an oxide-based crystalline material, an oxide-based glass material, and an oxide-based glass ceramic material.

[0059] In addition, examples of solid electrolytes capable of conducting sodium ions include sodium-containing phosphate compounds having a Nasicon structure, oxides having a perovskite structure, and oxides having a garnet or garnet-like structure. Examples of sodium-containing phosphate compounds having a Nasicon structure include Na x M y (PO4)3 (1≦x≦2, 1≦y≦2, M is at least one selected from the group consisting of Ti, Ge, Al, Ga and Zr).

[0060] The solid electrolyte layer may contain a binder and / or a sintering aid. The binder and / or sintering aid contained in the solid electrolyte layer may be selected from, for example, materials similar to the binder and / or sintering aid that may be contained in the positive electrode active material portion and / or the negative electrode active material portion.

[0061] The thickness of the solid electrolyte layer is not particularly limited, and may be, for example, 1 μm or more and 15 μm or less, and particularly 1 μm or more and 5 μm or less.

[0062] In a preferred embodiment of the solid electrolyte layer 130, the solid electrolyte layer 130 may cover one side surface of the interlayer conductive layer 170 and one side surface of the positive electrode layer 110 or the negative electrode layer 120 that sandwich the interlayer conductive layer 170. In the illustrated example ( FIG. 1 ), the solid electrolyte layer 130 may cover one side surface of the positive electrode active material layer 111 and the positive electrode current collector layer 112 that sandwich the interlayer conductive layer 170, and one side surface of the interlayer conductive layer 170. According to this coating embodiment, since one side surface of the positive electrode layer 110 or the negative electrode layer 120 is coated with the solid electrolyte layer, unintended short-circuiting of the electrode layers can be prevented.

[0063] In a more preferable coating mode of the solid electrolyte layer 130, the solid electrolyte layer 130 may be coated so as to straddle the current collecting layer and the active material layer that sandwich the interlayer conductive layer 170. In other words, the outer surfaces of the current collecting layer and the active material layer, excluding the side surfaces of the current collecting layer exposed from the solid battery element, may be coated with the solid electrolyte layer 130. According to the above coating mode, unintended short-circuiting of the electrode layers can be effectively prevented.

[0064] 2.Interlayer conductive layer The interlayer conductive layer 170 is located between the solid-state battery elements 141. More specifically, the interlayer conductive layer 170 is sandwiched between the positive electrode layer 110 or the negative electrode layer 120 of one solid-state battery element 141 and the positive electrode layer 110 or the negative electrode layer 120 of the other solid-state battery element 141.

[0065] In FIG. 1 showing an example, the interlayer conductive layer 170 may be sandwiched between positive electrode layers 110. However, this is not limiting, and the interlayer conductive layer 170 may also be sandwiched between negative electrode layers 120 (see FIG. 2). In other words, the interlayer conductive layer 170 may be sandwiched between electrode layers of the same polarity. This allows the electrode layers of the same polarity to be electrically connected to each other.

[0066] The interlayer conductive layer 170 is conductive, and therefore can provide electrical conduction between the positive electrode layers 110 or the negative electrode layers 120 that are in contact with the interlayer conductive layer 170 on both sides in the stacking direction.

[0067] The constituent material used for the interlayer conductive layer 170 may contain a conductive material and a solid electrolyte.

[0068] The conductive material used for the interlayer conductive layer 170 that electrically connects the positive electrode current collector layers 112 to each other may be, for example, at least one selected from the group consisting of carbon materials, silver, palladium, gold, platinum, aluminum, copper, nickel-lithium transition metal composite oxides, and lithium-transition metal phosphate compounds.

[0069] The conductive material used for the interlayer conductive layer 170 that electrically connects the negative electrode current collector layers 122 to each other may be at least one selected from the group consisting of carbon materials, silver, palladium, gold, platinum, aluminum, copper, and nickel.

[0070] Specific materials for the solid electrolyte may be those described in detail in "1-2. Solid Electrolyte Layer." Furthermore, the solid electrolyte ratio is 10% by weight or more and 35% by weight or less based on the entire interlayer conductive layer 170. In the present disclosure, the interlayer conductive layer is composed of a conductive material and a solid electrolyte. Therefore, if the solid electrolyte ratio in the interlayer conductive layer is 10% by weight based on the entire interlayer conductive layer, the conductive material is 90% by weight. If the solid electrolyte ratio in the interlayer conductive layer is 35% by weight based on the entire interlayer conductive layer, the conductive material is 65% by weight. Within this numerical range, the strength of the interlayer conductive layer 170 can be made lower than the strength of the positive electrode layer 110 or the negative electrode layer 120 that sandwiches the interlayer conductive layer 170. Therefore, when stress accumulates inside the solid-state battery, the stress can be concentrated in the interlayer conductive layer 170, which has low strength. For example, the stress can be relieved by cracking the interlayer conductive layer 170. If the solid electrolyte content of the interlayer conductive layer 170 is 10% by weight or less, it is difficult to maintain the shape of the sintered body. Therefore, the solid electrolyte content of at least the interlayer conductive layer 170 is set to 10% by weight or more. The detailed numerical range of the solid electrolyte content will be described in detail in the "Examples" section below.

[0071] Next, the terminal electrodes, the insulating outer layer, the insulating coating film, the inorganic film, and the supporting substrate will be described as additional components of the solid state battery of the present disclosure.

[0072] 3.Terminal electrode The terminal electrodes are provided on the end faces of the laminate 140. As an example, in Fig. 4, terminal electrodes 151 and 152 may be provided on each of the side faces of the laminate 140 that are positioned in a direction intersecting the stacking direction of the laminate 140.

[0073] More specifically, the terminal electrodes include a positive electrode side terminal electrode 151 connected to the positive electrode layer 110 and a negative electrode side terminal electrode 152 connected to the negative electrode layer 120, and the positive electrode side terminal electrode 151 may be formed on one side surface (the right side in FIG. 4), and the negative electrode side terminal electrode 152 may be provided so as to face the positive electrode side terminal electrode 151 (the left side in FIG. 4).

[0074] The terminal electrodes 151 and 152 may contain a conductive material. The conductive material is a material having electrical conductivity, and specific examples thereof include carbon materials and metal materials. Note that, in this specification, "conductive" means a material having a volume resistivity of 10 7 This means that the resistance is Ω·cm or less.

[0075] The metal material is not particularly limited as long as it is conductive, but examples thereof include at least one selected from the group consisting of silver, gold, platinum, aluminum, copper, palladium, zinc, tin, and nickel. Composite metals such as Ag-coated Cu and / or Ag-coated CuNi are also acceptable. Silver is a preferred metal material because it has high conductivity and exhibits minimal change in conductivity even in high-temperature, high-humidity environments.

[0076] 4. Insulating outer layer The solid-state battery of the present disclosure may include an insulating outer layer 160 as an additional component. Specifically, the insulating outer layer 160 may be provided on the outside of the laminate 140 (see FIGS. 1 to 3). The insulating outer layer 160 is generally formed on the outermost surface of the laminate 140 to electrically, physically, and / or chemically protect the laminate 140. In particular, the insulating outer layer 160 includes an insulating outer layer 160 on the top surface side of the solid-state battery 100 and an insulating outer layer 160 on the bottom surface side. The insulating outer layer 160 may also be provided on the side of the laminate 140 on which the terminal electrodes 151 and 152 are not provided (the side of the solid-state battery element 141 in the direction perpendicular to the paper surface in FIG. 4). The material constituting the insulating outer layer preferably has excellent insulation properties, durability, and / or moisture resistance, and is environmentally safe, and may include, for example, a resin material, a glass material, and / or a ceramic material. Furthermore, the insulating outer layer may have the form of a fired body because it is manufactured by integral firing. Alternatively, the insulating outer layer 160 may not be provided and the device may be enclosed in a resin or ceramic package.

[0077] 5.Coating insulation film The solid-state battery of the present disclosure may include an insulating coating film 200 as an additional configuration. The insulating coating film 200 may be provided so as to cover the terminal electrodes 151, 152 and the laminate 140 (see FIG. 4). The insulating coating film 200 preferably corresponds to a resin. In other words, the insulating coating film 200 preferably includes a resin material. As can be seen from the embodiment shown in FIG. 4, this means that the laminate 140 provided on the support substrate 400 is sealed with the resin material of the insulating coating film 200. The insulating coating film 200 made of such a resin material, in combination with the inorganic film 300 described below, effectively contributes to reducing moisture penetration.

[0078] The insulating coating material may be any material that exhibits insulating properties. For example, if the insulating coating material contains a resin, the resin may be either a thermosetting resin or a thermoplastic resin. Specific examples of the resin material for the insulating coating material include, but are not limited to, epoxy resins, silicone resins, and / or liquid crystal polymers. By way of example only, the thickness of the insulating coating material may be 30 μm or more and 1000 μm or less, for example, 50 μm or more and 300 μm or less.

[0079] In addition, the insulating coating film is not essential for the solid-state battery, and a solid-state battery that does not have the insulating coating film may also be considered.

[0080] 6. Inorganic membrane As an additional configuration of the solid-state battery of the present disclosure, an inorganic film 300 may be provided to cover the coated insulating film 200. As shown in Fig. 4, the inorganic film 300 is positioned on the coated insulating film 200, and therefore has a form that, together with the coated insulating film 200, largely envelops the stack 140 on the support substrate 400 as a whole.

[0081] The inorganic film 300 preferably has a thin film form. The material of the inorganic film is not particularly limited as long as it contributes to the formation of an inorganic film having a thin film form, and may be metal, glass, oxide ceramics, or a mixture thereof. In a preferred embodiment, the inorganic film may contain a metal component. That is, the inorganic film may preferably be a metal thin film. By way of example only, the thickness of such an inorganic film may be 0.1 μm or more and 100 μm or less, for example, 1 μm or more and 50 μm or less.

[0082] In particular, depending on the manufacturing method, the inorganic film 300 may be a dry-plated film. Such a dry-plated film is obtained by a vapor-phase method such as physical vapor deposition (PVD) or chemical vapor deposition (CVD), and has an extremely small thickness on the order of nanometers or microns. Such a thin dry-plated film contributes to more compact packaging.

[0083] The dry-plated film may be composed of, for example, at least one metal component or semimetal component selected from the group consisting of aluminum (Al), nickel (Ni), palladium (Pd), silver (Ag), tin (Sn), gold (Au), copper (Cu), titanium (Ti), platinum (Pt), silicon (Si), and stainless steel, an inorganic oxide, and / or a glass component. Dry-plated films composed of such components are chemically and / or thermally stable, and therefore may result in solid-state batteries with excellent chemical resistance, weather resistance, and / or heat resistance, and improved long-term reliability.

[0084] In addition, an inorganic film is not necessarily essential for a solid-state battery, and a solid-state battery without an inorganic film is also conceivable.

[0085] 7. Support substrate The solid-state battery of the present disclosure may include a support substrate 400 as an additional configuration. The support substrate 400 is a substrate provided to support the stack 140. The support substrate is positioned on one side of the solid-state battery that forms a main surface to provide support. As a "substrate," the support substrate preferably has a thin plate-like shape as a whole.

[0086] The support substrate 400 may be, for example, a resin substrate or a ceramic substrate, with a water-resistant substrate being preferable. In a preferred embodiment, the support substrate 400 may be a ceramic substrate. That is, the support substrate 400 may contain ceramic, which may constitute the base material of the substrate. A support substrate made of ceramic contributes to preventing water vapor transmission and is also preferable in terms of heat resistance during substrate mounting. Such a ceramic substrate can be obtained through firing, for example, by firing a green sheet laminate. In this regard, the ceramic substrate may be, for example, an LTCC substrate (Low Temperature Co-fired Ceramics) or an HTCC substrate (High Temperature Co-fired Ceramics). By way of example only, the thickness of the support substrate may be 20 μm or more and 1000 μm or less, for example, 100 μm or more and 300 μm or less.

[0087] The support substrate 400 may also function as a terminal substrate for the laminate 140. That is, a packaged solid-state battery with a substrate interposed therebetween may be mounted on another secondary substrate such as a printed wiring board. For example, the solid-state battery may be surface-mounted via the support substrate through solder reflow or the like. For this reason, the packaged solid-state battery may be an SMD-type battery. In particular, when the terminal substrate is made of a ceramic substrate, the solid-state battery may be an SMD-type battery that has high heat resistance and can be solder-mounted.

[0088] Since it is a terminal substrate, it preferably has wiring, and in particular, it preferably has wiring 410 (see FIG. 4) that electrically connects the upper and lower surfaces or the upper and lower surface layers. That is, a preferred embodiment of the support substrate has wiring that electrically connects the upper and lower surfaces of the substrate, and may be a terminal substrate for the external terminals of a packaged solid-state battery.

[0089] The wiring 410 in the terminal substrate is not particularly limited and may have any form as long as it contributes to electrical connection between the upper and lower surfaces of the substrate. Because it contributes to electrical connection, the wiring 410 in the terminal substrate can also be considered a conductive portion of the substrate. Such a conductive portion of the substrate may have the form of a wiring layer, a via, and / or a land. For example, in the embodiment shown in FIG. 4, vias 412 and / or lands 411 are provided in the support substrate 400. The term "via" here refers to a member for electrically connecting the support substrate in the vertical direction, i.e., the thickness direction of the substrate. For example, a filled via is preferred, and it may also take the form of an inner via. Furthermore, the term "land" in this specification refers to a terminal portion / connection portion for electrical connection (preferably a terminal portion / connection portion connected to a via) provided on the upper and / or lower main surface of the support substrate. For example, it may be a square land or a round land.

[0090] [Electronic device configuration] The electronic device of the present disclosure is one in which the above-described solid-state battery is surface-mounted. Specifically, the wiring of the support substrate 400 enables the surface mounting of the solid-state battery. In this specification, "surface mounting" refers to a technique in which a solid-state battery is directly fixed to a pattern formed on a substrate. As an example, the above-described solid-state battery 1 may be mounted on a printed circuit board or the like and packaged. Furthermore, electronic components other than the solid-state battery may be mounted on the electronic device.

[0091] [Solid-state battery manufacturing method] The solid-state battery of the present disclosure is manufactured through processes including (1) preparation of a laminate, (2) preparation of a terminal electrode material, (3) firing of the laminate, (4) application of the terminal electrode material, (5) curing of the terminal electrode material, (6) fixing to a support substrate, and (7) formation of a covering insulating film and an inorganic film. These processes are explained in order below.

[0092] (1) Preparation of the laminate (see Figures 5(a) and (b)) In producing the laminate, a sheet containing a solid electrolyte, a paste for a positive electrode active material layer, a paste for a positive electrode current collector layer, a paste for a negative electrode active material layer, a paste for a negative electrode current collector layer, and a paste for an interlayer conductive layer are prepared.

[0093] The sheet containing the solid electrolyte is formed by mixing the solid electrolyte, an organic binder, a solvent, and any additives to prepare a slurry, and then firing the prepared slurry to form a sheet.

[0094] The paste for the positive electrode active material is prepared by mixing a positive electrode active material, a solid electrolyte, a conductive material, an organic binder, a solvent, and any additives. The paste for the positive electrode current collector layer is prepared by mixing a solid electrolyte, a conductive material, an organic binder, a solvent, and any additives. The proportion of the solid electrolyte in the paste for the positive electrode current collector layer is 40% by weight or more and 60% by weight or less based on the total weight.

[0095] The negative electrode active material paste is prepared by mixing a negative electrode active material, a solid electrolyte, a conductive material, an organic binder, a solvent, and any additives. The negative electrode current collector layer paste is prepared by mixing a solid electrolyte, a conductive material, an organic binder, a solvent, and any additives. The solid electrolyte ratio in the negative electrode current collector layer paste is 40% by weight or more and 60% by weight or less based on the total weight.

[0096] The paste for the interlayer conductive layer is prepared by mixing a solid electrolyte, a conductive material, an organic binder, a solvent, and optional additives. The solid electrolyte ratio in the paste for the interlayer conductive layer is 10% by weight or more and 35% by weight or less of the total.

[0097] After preparing the above pastes, the process moves on to preparing the laminate. A paste P22 for the negative electrode current collector layer is printed on a sheet S containing a solid electrolyte, and a paste P21 for the negative electrode active material is printed on the paste P22 for the negative electrode current collector layer. If necessary, a solid electrolyte part N that acts as a solid electrolyte may also be printed (see FIG. 5(b)). The solid electrolyte part N is intended to be a slurry made by mixing a solid electrolyte, an organic binder, a solvent, and optional additives.

[0098] Furthermore, a positive electrode active material paste P11 is printed on another sheet S containing a solid electrolyte, and a positive electrode current collector layer paste P12 is printed on the positive electrode active material paste P11. A solid electrolyte portion N acting as a solid electrolyte may be printed as needed (see FIG. 5(a)). An interlayer conductive layer paste P30 is printed on the positive electrode current collector layer paste. A positive electrode current collector layer paste P12 and a positive electrode active material paste P11 are printed, in that order, on the interlayer conductive layer paste P30. A solid electrolyte portion N acting as a solid electrolyte may be printed as needed. These sheets printed with the negative electrode paste and sheets printed with the positive electrode paste are alternately stacked to obtain a laminate. The outermost layer (top and / or bottom layer) of the laminate may be an electrolyte layer, an insulating layer, or an electrode layer.

[0099] (2) Preparation of terminal electrode material First, a terminal electrode material (for example, a conductive paste) is prepared as the material for the terminal electrodes 151 and 152. Ag is prepared as the conductive material. Here, the terminal electrode material may further contain resin and solvent as additional elements. Note that the term "terminal electrode material" as used herein refers to a material that can form a flow in the hydrodynamic sense or a material that can maintain such a flow. Examples of such materials include liquids such as pastes, solutions, and suspensions.

[0100] The solvent dissolves the resin binder, and for example, an organic solvent may be used. The organic solvent is not particularly limited, but includes alcohols including methanol, ethanol, 1-propanol, 2-propanol, hexanol, and cyclohexanol, glycols including ethylene glycol and propylene glycol, ketones including methyl ethyl ketone, diethyl ketone, and methyl isobutyl ketone, terpenes including α-terpineol, β-terpineol, and γ-terpineol, ethylene glycol monoalkyl ethers, ethylene glycol dialkyl ethers, diethylene glycol monoalkyl ethers, diethylene glycol dialkyl ethers, and ethylene glycol Cholesterol monoalkyl ether acetates, ethylene glycol dialkyl ether acetates, diethylene glycol monoalkyl ether acetates, diethylene glycol dialkyl ether acetates, propylene glycol monoalkyl ethers, propylene glycol dialkyl ethers, propylene glycol monoalkyl ether acetates, propylene glycol dialkyl ether acetates, and / or monoalkyl cellosolves can be used alone, or a mixture of at least one or two or more solvents selected from these solvents can also be used. As an example of an organic solvent, an alcohol-based solvent such as terpineol is preferably used. Furthermore, a dispersant may be added to the solvent.

[0101] After the terminal electrode material is prepared, the terminal electrode material is applied to the exposed positive electrode side and the exposed negative electrode side of the battery body.

[0102] (3) Firing of the laminate The firing of the laminate is carried out by heating in a nitrogen gas atmosphere containing oxygen gas or in the air at a desired firing temperature (for example, a firing peak temperature in the range of 300°C to 600°C), which is merely an example. The firing may be carried out while applying pressure to the laminate precursor in the stacking direction (and in some cases in the stacking direction and a direction perpendicular to the stacking direction).

[0103] (4) Applying terminal electrode material After the terminal electrode material is prepared, the terminal electrode material is applied to the exposed positive electrode side and the exposed negative electrode side of the laminate.

[0104] (5) Hardening of terminal electrode material The laminate applied to the exposed positive electrode side surface and the exposed negative electrode side surface is cured at a desired curing temperature (for example, in the range of 100°C to 300°C).

[0105] (6) Fixing to a supporting substrate The support substrate has vias and / or lands to allow surface mounting to a secondary substrate. For example, it can be obtained by stacking and firing multiple green sheets. This is especially true when the support substrate is a ceramic substrate. The support substrate can be prepared, for example, in accordance with the preparation of an LTCC substrate.

[0106] The vias and / or lands in the support substrate are manufactured by, for example, forming holes (diameter size: approximately 50 μm or more and 200 μm or less) using a punch press or a carbon dioxide laser, and filling the holes with a conductive paste material, or by using a printing method.

[0107] After manufacturing the support substrate, the conductive portion of the support substrate and the terminal electrode of the laminate are arranged so as to be electrically connected to each other. Then, a conductive paste may be applied to the support substrate, thereby electrically connecting the conductive portion of the support substrate and the terminal electrode to each other. As the conductive paste, in addition to Ag conductive paste, a nanopaste, an alloy paste, a brazing material, or other conductive paste that does not require cleaning with flux or the like after formation can be used.

[0108] (7) Formation of insulating and inorganic coating films Next, a coating insulating film is formed so as to cover the laminate on the support substrate. Therefore, raw materials for the coating insulating film are provided so as to completely cover the battery element on the support substrate. When the coating insulating film is made of a resin material, a resin precursor is provided on the support substrate and cured to form the coating insulating film.

[0109] In a preferred embodiment, the insulating coating film may be molded by applying pressure in a mold. By way of example only, the insulating coating film that seals the battery element on the support substrate may be molded using a compression mold. If the insulating coating film is made of a resin material typically used in molding, the raw material may be granular or thermoplastic. Such molding is not limited to mold molding, and may also be performed through polishing, laser processing, and / or chemical treatment.

[0110] Next, an inorganic film is formed. The inorganic film may be formed by, for example, dry plating, to form a dry-plated film. More specifically, dry plating is performed to form an inorganic film on the exposed surface other than the bottom surface of the coating precursor (i.e., other than the bottom surface of the support substrate). In a preferred embodiment, sputtering is performed to form a sputtered film on the exposed outer surface other than the bottom surface of the coating precursor.

[0111] By going through the steps described above, the solid state battery of the present disclosure can finally be obtained. [Example]

[0112] A demonstration test was carried out on the solid state battery of the present disclosure. Specifically, the solid state batteries of Examples 1 to 5 and Comparative Examples 1 to 5 shown below were manufactured.

[0113] <Common configuration in the examples> 1, the solid state batteries of Examples 1 to 5 had a structure in which two solid state battery elements 141 were stacked with an interlayer conductive layer 170 interposed therebetween, and the interlayer conductive layer 170 was sandwiched between positive electrode layers 110. As an example of the material of each layer, the positive electrode active material layer 111 was LiCoO2, and the positive electrode current collector layer 112, the negative electrode active material layer 121, the negative electrode current collector layer 122, and the interlayer conductive layer 170 were made of a carbon material. Note that the material of each layer, the number of layers, etc. are not limited to this example.

[0114] <Configuration specific to Example 1> For the solid state battery of Example 1, the solid electrolyte ratios in the positive electrode current collector layer and the interlayer conductive layer were set as follows: Positive electrode current collector layer: conductive material (50% by weight), solid electrolyte (50% by weight) Interlayer conductive layer: conductive material (80% by weight), solid electrolyte (20% by weight)

[0115] <Configuration specific to Example 2> For the solid state battery of Example 2, the solid electrolyte ratios in the positive electrode current collector layer and the interlayer conductive layer were set as follows: Positive electrode current collector layer: conductive material (50% by weight), solid electrolyte (50% by weight) Interlayer conductive layer: conductive material (90% by weight), solid electrolyte (10% by weight)

[0116] <Configuration specific to Example 3> For the solid state battery of Example 3, the solid electrolyte ratios in the positive electrode current collector layer and the interlayer conductive layer were set as follows: Positive electrode current collector layer: conductive material (50% by weight), solid electrolyte (50% by weight) Interlayer conductive layer: conductive material (65% by weight), solid electrolyte (35% by weight)

[0117] <Configuration specific to Example 4> For the solid state battery of Example 4, the solid electrolyte ratios in the positive electrode current collector layer and the interlayer conductive layer were set as follows: Positive electrode current collector layer: conductive material (60% by weight), solid electrolyte (40% by weight) Interlayer conductive layer: conductive material (80% by weight), solid electrolyte (20% by weight)

[0118] <Configuration specific to Example 5> For the solid state battery of Example 5, the solid electrolyte ratios in the positive electrode current collector layer and the interlayer conductive layer were set as follows: Positive electrode current collector layer: conductive material (40% by weight), solid electrolyte (60% by weight) Interlayer conductive layer: conductive material (80% by weight), solid electrolyte (20% by weight)

[0119] <Configuration of Comparative Example 1> A solid state battery without an interlayer conductive layer was manufactured as the solid state battery of Comparative Example 1. The positive electrode current collector layer was set as follows. Positive electrode current collector layer: conductive material (80% by weight), solid electrolyte (20% by weight)

[0120] <Configuration of Comparative Example 2> For the solid state battery of Comparative Example 2, the solid electrolyte ratio was set as follows instead of that of the solid state battery of Example 1. Positive electrode current collector layer: conductive material (50% by weight), solid electrolyte (50% by weight) Interlayer conductive layer: conductive material (95% by weight), solid electrolyte (5% by weight)

[0121] <Configuration of Comparative Example 3> For the solid state battery of Comparative Example 3, the solid electrolyte ratio was set as follows instead of that of the solid state battery of Example 1. Positive electrode current collector layer: conductive material (50% by weight), solid electrolyte (50% by weight) Interlayer conductive layer: conductive material (60% by weight), solid electrolyte (40% by weight)

[0122] <Configuration of Comparative Example 4> For the solid state battery of Comparative Example 4, the solid electrolyte ratio was set as follows instead of that of the solid state battery of Example 1. Positive electrode current collector layer: conductive material (30% by weight), solid electrolyte (70% by weight) Interlayer conductive layer: conductive material (80% by weight), solid electrolyte (20% by weight)

[0123] <Configuration of Comparative Example 5> For the solid state battery of Comparative Example 5, the solid electrolyte ratio was set as follows instead of that of the solid state battery of Example 1. Positive electrode current collector layer: conductive material (70% by weight), solid electrolyte (30% by weight) Interlayer conductive layer: conductive material (80% by weight), solid electrolyte (20% by weight)

[0124] A high-temperature charge-discharge cycle short-circuit test and a production suitability test were carried out on the solid-state batteries of Examples 1 to 5 and Comparative Examples 1 to 5. The details of each test are shown below.

[0125] -High temperature charge / discharge cycle short circuit test- A charge-discharge cycle test was conducted at the design voltage and design current using a charge-discharge tester (TOSCAT-3100) manufactured by Toyo Systems, and the short circuit occurrence rate of the solid-state battery was confirmed. The indicators for the short circuit occurrence rate in this test are as follows: ◎: Short circuit occurrence rate 20% or less ○: Short circuit occurrence rate is greater than 20% and less than 60% ×: Short circuit occurrence rate is greater than 60%

[0126] -Production aptitude test- The production suitability test involved visually inspecting the solid-state batteries for shape abnormalities when they were produced. The index of the occurrence rate of shape abnormalities is as follows: ◎: Shape abnormality rate 10% or less ○: Shape abnormality rate is greater than 10% and less than 30% ×: Shape abnormality rate is greater than 30%

[0127] The test results are shown in the table below.

[0128] [Table 1]

[0129] According to the above test results, the solid state batteries of Examples 1 to 5 showed good results in the high-temperature charge-discharge test and the production suitability test because the solid state electrolyte ratio in the positive electrode layer sandwiching the interlayer conductive layer was in the range of 40% by weight to 60% by weight, and the solid state electrolyte ratio in the interlayer conductive layer was in the range of 10% by weight to 35% by weight based on the layer containing the solid electrolyte. In particular, the solid state battery of Example 1 showed better results than the solid state batteries of Examples 2 to 5 in the demonstration test.

[0130] On the other hand, the solid-state battery of Comparative Example 1 did not have an interlayer conductive layer, and therefore a short circuit occurred due to the stress of the solid-state battery. The solid-state battery of Comparative Example 2 could not maintain the shape of the sintered body due to the low solid electrolyte ratio in the interlayer conductive layer, and therefore a solid-state battery could not be manufactured in the first place. The solid-state batteries of Comparative Examples 3 and 5 did not achieve a stress relaxation effect due to the strength difference because the difference between the solid electrolyte ratio in the interlayer conductive layer and the solid electrolyte ratio in the positive electrode current collector layer was small. The solid-state battery of Comparative Example 4 did not function as a solid-state battery due to the relatively high solid electrolyte ratio in the positive electrode current collector layer, resulting in high resistance, and therefore a high-temperature charge / discharge test could not be performed.

[0131] According to the above-mentioned demonstration tests (high-temperature charge / discharge tests and production suitability tests), it was found that stress due to volume change can be alleviated if the solid electrolyte ratio in the positive electrode layer or negative electrode layer sandwiching the interlayer conductive layer is in the range of 40% by weight or more and 60% by weight or less, and if the solid electrolyte ratio in the interlayer conductive layer is in the range of 10% by weight or more and 35% by weight or less based on the layer containing the solid electrolyte.

[0132] Aspects of the solid-state battery and electronic device of the present disclosure are as follows. <1> a plurality of solid-state battery elements each including a stack of a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer; an interlayer conductive layer located between each of the solid-state battery elements; the interlayer conductive layer is sandwiched between a positive electrode layer or a negative electrode layer of one solid-state battery element and a positive electrode layer or a negative electrode layer of the other solid-state battery element, the positive electrode layer or the negative electrode layer sandwiching the interlayer conductive layer contains a solid electrolyte, a solid electrolyte ratio of the positive electrode layer or the negative electrode layer sandwiching the interlayer conductive layer is 40% by weight or more and 60% by weight or less based on the layer containing the solid electrolyte; A solid-state battery, wherein the solid electrolyte ratio of the interlayer conductive layer is 10% by weight or more and 35% by weight or less based on the layer containing the solid electrolyte. <2> the positive electrode layer or the negative electrode layer includes an active material layer containing an electrode active material and a current collector layer in contact with the interlayer conductive layer, The current collector layer contains the solid electrolyte. <1> The solid-state battery according to claim 1. <3> In a cross-sectional view, the current collector layer is provided up to an end of the solid-state battery element, and the active material layer is located inside the end. <2> The solid-state battery according to claim 1. <4> the active material layers of the electrode layers located on both sides of the interlayer conductive layer are disposed on the inner side of the counter electrode layer facing the electrode layer; <2> or <3> The solid-state battery according to claim 1. <5> a counter electrode layer facing the electrode layer includes an active material layer containing an electrode active material and a current collector layer in contact with the interlayer conductive layer, the active material layers of the electrode layers located on both sides of the interlayer conductive layer are disposed on the inner side of the active material layers; <4> The solid-state battery according to claim 1. <6> The interlayer conductive layer is sandwiched between electrode layers of the same polarity. <1> ~ <5> 10. The solid-state battery according to claim 9, wherein the solid-state battery is a <7> The plurality of solid-state battery elements are electrically connected in parallel to each other. <1> ~ <6> 10. The solid-state battery according to claim 9, wherein the solid-state battery is a <8> one side surface of the interlayer conductive layer and one side surface of the positive electrode layer or the negative electrode layer sandwiching the interlayer conductive layer are covered with the solid electrolyte layer; <1> ~ <7> 10. The solid-state battery according to claim 9, wherein the solid-state battery is a <9> the solid electrolyte layer is coated across the current collector layer and the active material layer, which sandwich the interlayer conductive layer; <1> ~ <8> 10. The solid-state battery according to claim 9, wherein the solid-state battery is a <10> The solid-state battery element is made of a sintered body. <1> ~ <9> 10. The solid-state battery according to claim 9, wherein the solid-state battery is a <11> The solid-state battery is packaged for surface mounting. <1> ~ <10> 10. The solid-state battery according to claim 9, wherein the solid-state battery is a <12> the positive electrode layer and the negative electrode layer are layers capable of absorbing and releasing lithium ions; <1> ~ <11> 10. The solid-state battery according to claim 9, wherein the solid-state battery is a <13> <1> ~ <12> 1. An electronic device in which the solid-state battery according to any one of claims 1 to 9 is surface-mounted.

[0133] It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments, but should be defined based on the claims. The technical scope of the present disclosure also includes all modifications within the meaning and scope of the claims. For example, the solid-state battery is not limited to a substantially hexahedral shape, but may also be a polyhedral, cylindrical, or spherical shape. [Industrial Applicability]

[0134] The packaged solid-state batteries of the present disclosure can be used in a variety of fields where battery use or storage is envisioned. By way of example only, the packaged solid-state batteries of the present disclosure can be used in electronic packaging. The present disclosure can also be used in the electrical, information, and communications fields where mobile devices and the like are used (for example, the electrical and electronic equipment fields or mobile device fields including small electronic devices such as mobile phones, smartphones, laptops and digital cameras, activity monitors, arm computers, electronic paper, RFID tags, card-type electronic money, and smart watches), home and small industrial applications (for example, power tools, golf carts, and home, nursing care, and industrial robots), large industrial applications (for example, forklifts, elevators, and port cranes), transportation systems (for example, hybrid cars, electric cars, buses, trains, electrically assisted bicycles, and electric motorcycles), power system applications (for example, various types of power generation, road conditioners, smart grids, and general home-installed energy storage systems), medical applications (for medical devices such as earphones and hearing aids), pharmaceutical applications (for example, medication management systems), the IoT field, and space and deep-sea applications (for example, space probes, submersible research vessels, and the like). [Explanation of symbols]

[0135] 100 solid state battery 110 Positive electrode layer 111 Cathode active material layer 112 Positive electrode current collector layer 120 negative electrode layer 121 Negative electrode active material layer 122 Negative electrode current collector layer 130 Solid electrolyte layer 140 laminate 141 Solid-state battery elements 151 Positive electrode layer side terminal electrode 152 Negative layer side terminal electrode 160 Insulating outer layer 170 Interlayer Conductive Layer 200 Coated insulation film 300 Inorganic membrane 400 Support substrate 410 Wiring 411 rand 412 Beer S seat P11 Positive electrode active material paste P12 Positive electrode current collector layer paste P21 Negative electrode active material paste P22 Negative electrode current collector layer paste P30 Interlayer Conductive Layer Paste N Solid electrolyte section

Claims

1. a plurality of solid-state battery elements each including a stack of a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer; an interlayer conductive layer located between each of the solid-state battery elements; the interlayer conductive layer is sandwiched between a positive electrode layer or a negative electrode layer of one solid-state battery element and a positive electrode layer or a negative electrode layer of the other solid-state battery element, and the positive electrode layer or the negative electrode layer sandwiching the interlayer conductive layer contains a solid electrolyte, a solid electrolyte ratio in a current collector layer that is included in the positive electrode layer and in contact with the interlayer conductive layer, or in a current collector layer that is included in the negative electrode layer and in contact with the interlayer conductive layer, is 40 wt % or more and 60 wt % or less based on the layer containing the solid electrolyte, A solid-state battery, wherein the solid electrolyte ratio of the interlayer conductive layer is 10% by weight or more and 35% by weight or less based on the layer including the solid electrolyte.

2. The solid-state battery according to claim 1 , wherein, in a cross-sectional view, the current collector layer is provided up to an end of the solid-state battery element, and the active material layer is located inside the end.

3. The solid-state battery according to claim 1 , wherein the active material layers of the electrode layers located on both sides of the interlayer conductive layer are disposed more inward than the counter electrode layer facing the electrode layer.

4. a counter electrode layer facing the electrode layer includes an active material layer containing an electrode active material and a current collector layer in contact with the interlayer conductive layer, The solid-state battery according to claim 3 , wherein the active material layers of the electrode layers located on both sides of the interlayer conductive layer are disposed more inward than the active material layers.

5. The solid-state battery according to claim 1 , wherein the interlayer conductive layer is sandwiched between electrode layers of the same polarity.

6. The solid-state battery according to claim 1 , wherein the plurality of solid-state battery elements are electrically connected in parallel with each other.

7. 2. The solid-state battery according to claim 1, wherein one side surface of the interlayer conductive layer and one side surface of the positive electrode layer or the negative electrode layer sandwiching the interlayer conductive layer are covered with the solid electrolyte layer.

8. The solid-state battery according to claim 1 , wherein the solid electrolyte layer covers the current collecting layer and the active material layer, the current collecting layer sandwiching the interlayer conductive layer, so as to straddle the active material layer.

9. The solid-state battery according to claim 1 , wherein the solid-state battery element is made of a sintered body.

10. The solid-state battery of claim 1 , wherein the solid-state battery is packaged for surface mounting.

11. The solid-state battery according to claim 1 , wherein the positive electrode layer and the negative electrode layer are layers capable of absorbing and releasing lithium ions.

12. An electronic device having the solid-state battery according to claim 1 surface-mounted thereon.

Images